WO2015045386A1 - Nonaqueous secondary battery - Google Patents

Nonaqueous secondary battery Download PDF

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Publication number
WO2015045386A1
WO2015045386A1 PCT/JP2014/004910 JP2014004910W WO2015045386A1 WO 2015045386 A1 WO2015045386 A1 WO 2015045386A1 JP 2014004910 W JP2014004910 W JP 2014004910W WO 2015045386 A1 WO2015045386 A1 WO 2015045386A1
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Prior art keywords
substituent
substituted
group
battery
electrolytic solution
Prior art date
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PCT/JP2014/004910
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French (fr)
Japanese (ja)
Inventor
山田　淳夫
裕貴 山田
智之 河合
佳浩 中垣
浩平 間瀬
雄紀 長谷川
合田　信弘
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国立大学法人東京大学
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Priority claimed from JP2014194343A external-priority patent/JP5817007B1/en
Priority claimed from JP2014194345A external-priority patent/JP5817009B1/en
Priority claimed from JP2014194344A external-priority patent/JP5817008B1/en
Priority claimed from JP2014194342A external-priority patent/JP5817006B1/en
Application filed by 国立大学法人東京大学 filed Critical 国立大学法人東京大学
Priority to US15/024,380 priority Critical patent/US20160218390A1/en
Priority to DE112014004439.3T priority patent/DE112014004439T5/en
Priority to KR1020167010614A priority patent/KR101967677B1/en
Priority to CN201480053186.5A priority patent/CN105594053B/en
Publication of WO2015045386A1 publication Critical patent/WO2015045386A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a non-aqueous secondary battery such as a lithium ion secondary battery.
  • Non-aqueous secondary batteries such as lithium ion secondary batteries are small and have high energy density, and are widely used as power sources for portable electronic devices.
  • the electrolytic solution is produced by dissolving a lithium salt in an organic solvent containing ethylene carbonate.
  • the above lithium metal composite oxide has an unstable structure compared to the discharged state.
  • energy such as heat is applied, it is considered that oxygen (O) is released along with the collapse of the crystal structure, and the released oxygen reacts with the electrolytic solution to generate combustion heat.
  • a mixed organic solvent containing ethylene carbonate which is widely used for an electrolytic solution, is low in viscosity and melting point of the electrolytic solution and becomes an electrolytic solution having a high ionic conductivity, but is easily volatilized. In the unlikely event that there is a gap or damage in the battery, there is a risk that it will be instantaneously released as a gas outside the battery system.
  • the electrolytic solution By using a low volatile liquid such as an ionic liquid as the electrolytic solution, it is conceivable to suppress the volatilization of the electrolytic solution when the battery is damaged.
  • the ionic liquid has a high viscosity and a low ionic conductivity compared to a normal electrolytic solution. For this reason, the input / output characteristics of the battery are deteriorated.
  • the inventor of the present application eagerly searched for an electrolytic solution and developed a new low-volatile electrolytic solution.
  • the inventors of the present application have found that a non-aqueous secondary battery having excellent input / output characteristics can be obtained by combining this new electrolyte with a positive electrode using a lithium metal composite oxide as an active material.
  • a lithium metal composite oxide having a spinel structure such as LiMn 2 O 4 may be mainly used.
  • the electrolytic solution is obtained by dissolving a lithium salt in a solvent containing ethylene carbonate (Patent Documents 1 and 2). In such a secondary battery, both the negative electrode and the positive electrode need to be reversibly charged and discharged.
  • a positive electrode active material of a lithium ion secondary battery a polyanion material having an olivine structure such as LiFePO 4 may be used.
  • a battery using an olivine-based active material is characterized by excellent safety, cycleability, and low cost.
  • the electrolytic solution is obtained by dissolving a metal salt in a solvent containing ethylene carbonate (Patent Documents 3 and 4).
  • both the negative electrode and the positive electrode need to be reversibly charged and discharged.
  • high rate capacity characteristics are desired.
  • the electrolytic solution is obtained by dissolving a lithium salt in a solvent containing ethylene carbonate (Patent Documents 1 and 2).
  • a lithium ion secondary battery performs a charge / discharge reaction reversibly.
  • the electrolytic solution is required to have high reduction resistance and oxidation resistance.
  • the battery body is used. It is necessary to increase the upper limit potential.
  • the electrolytic solution has a high oxidative decomposition potential that exceeds the maximum use potential of the positive electrode.
  • Patent Document 5 proposes to add a compound having a high reaction potential to the electrolytic solution.
  • the present inventor has developed an electrolytic solution having high oxidation resistance by a method different from the conventional technique.
  • the present invention has been made in view of such circumstances, and a first problem is to provide a non-aqueous secondary battery having excellent input / output characteristics.
  • the second problem is to provide a non-aqueous secondary battery that achieves both improved safety and reversible charge / discharge reaction.
  • a third problem is to provide a non-aqueous secondary battery having a novel electrolyte solution and positive electrode combination capable of reversible charge / discharge reaction and improving rate capacity characteristics.
  • the fourth problem is to provide a non-aqueous secondary battery that can be used at a high potential.
  • the non-aqueous secondary battery according to the first aspect of the present invention is a non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolyte solution
  • the positive electrode has a positive electrode active material having a lithium metal composite oxide having a layered rock salt structure
  • the electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element, Regarding the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io.
  • the first aspect of the present invention is that, as a result of earnest search, the inventor can reversibly charge and discharge a non-aqueous secondary battery including a positive electrode having a lithium metal composite oxide having a layered rock salt structure. This is due to the development of a new electrolyte with excellent input / output characteristics.
  • the non-aqueous secondary battery according to the second aspect of the present invention is a non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolytic solution, and the positive electrode has a lithium metal composite oxide having a spinel structure.
  • the electrolyte solution has an active material, and the electrolyte solution includes a metal salt having a cation of alkali metal, alkaline earth metal, or aluminum, and an organic solvent having a hetero element, and is derived from the organic solvent in a vibrational spectrum of the electrolyte solution.
  • the peak intensity when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io.
  • the present inventor is a novel capable of reversibly charging and discharging a non-aqueous secondary battery including a positive electrode having a lithium metal composite oxide having a spinel structure. Because of the development of a new electrolyte.
  • a non-aqueous secondary battery is a non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode has a positive electrode active material having a polyanion material,
  • the electrolytic solution includes a metal salt having an alkali metal, alkaline earth metal, or aluminum as a cation and an organic solvent having a hetero element, and the organic solvent has a peak intensity derived from the organic solvent in a vibrational spectrum of the electrolytic solution.
  • Io the intensity of the original peak of the solvent
  • Is Io.
  • the inventor has developed a novel non-aqueous secondary battery including a positive electrode having a polyanion-based material that can reversibly charge and discharge and improve rate capacity characteristics. This is due to the development of a combination of electrolyte and positive electrode.
  • a non-aqueous secondary battery is a non-aqueous secondary battery having a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and an electrolyte solution
  • the electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element,
  • the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io
  • the non-aqueous secondary battery is characterized in that the maximum usable potential of the positive electrode when Li / Li + is used as a reference potential is 4.5 V or more.
  • a non-aqueous secondary battery that achieves both improvement in safety and reversible charge / discharge reaction since the above-described novel electrolytic solution is used. can do.
  • a non-aqueous system having a combination of a novel electrolyte and a positive electrode that can reversibly charge and discharge and improve rate capacity characteristics.
  • a secondary battery can be provided.
  • non-aqueous secondary battery of the fourth aspect of the present invention since it has the above electrolyte, it can be used at a high potential, and the average voltage and battery capacity increase.
  • IR spectrum of the electrolyte solution of the electrolyte solution E12 It is IR spectrum of the electrolyte solution of the electrolyte solution E13. It is IR spectrum of the electrolyte solution of the electrolyte solution E14. It is IR spectrum of the electrolyte solution of the electrolyte solution E15. It is IR spectrum of the electrolyte solution of the electrolyte solution C6. It is IR spectrum of dimethyl carbonate. It is IR spectrum of the electrolyte solution of the electrolyte solution E16. It is IR spectrum of the electrolyte solution of the electrolyte solution E17. It is IR spectrum of the electrolyte solution of the electrolyte solution E18.
  • FIG. 10 is an XPS analysis result of carbon elements in negative electrode S, O-containing coating films of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16.
  • FIG. 10 is an XPS analysis result of fluorine element in negative electrode S, O-containing coating film of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16.
  • 10 is an XPS analysis result of nitrogen element in negative electrode S, O-containing coating film of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16.
  • 10 is an XPS analysis result of oxygen elements in negative electrode S and O-containing films of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16.
  • 10 is an XPS analysis result of sulfur element in negative electrode S, O-containing coating film of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16.
  • 10 is an XPS analysis result of a negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-16.
  • 20 shows the result of XPS analysis of a negative electrode S, O-containing film of Battery A-9 in Evaluation Example A-19.
  • 19 is a BF-STEM image of a negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-19. 19 shows the STEM analysis result for C of the negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-19. 19 shows the results of STEM analysis on O of the negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-19.
  • 19 shows STEM analysis results on S of negative electrode S and O-containing coating film of Battery A-8 in Evaluation Example A-19.
  • 19 shows the XPS analysis result for O of the positive electrode S, O-containing film of Battery A-8 in Evaluation Example A-19.
  • 19 shows the XPS analysis result for S of the positive electrode S, O-containing film of Battery A-8 in Evaluation Example A-19.
  • 19 shows the XPS analysis result for S of the positive electrode S, O-containing film of battery A-11 in Evaluation Example A-19.
  • 19 shows the XPS analysis result for O of the positive electrode S, O-containing film of battery A-11 in Evaluation Example A-19.
  • 19 shows the XPS analysis results for S of the positive electrode S and O-containing films of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19.
  • 19 shows XPS analysis results for S of positive electrode S and O-containing coatings of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19.
  • 19 shows the XPS analysis result for O of the positive electrode S, O-containing coating film of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19.
  • 19 shows the analysis results on O of the positive electrode S and O-containing coatings of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19.
  • 19 shows the analysis results on S of negative electrode S and O-containing films of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19.
  • 19 shows the analysis results on S of the negative electrode S and O-containing coating film of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19.
  • 19 shows the analysis results on O of the negative electrode S and O-containing films of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19.
  • 19 shows the analysis results on O of the negative electrode S and O-containing films of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19.
  • 7 is a surface analysis result of an aluminum foil after charge / discharge of a lithium ion secondary battery of Battery A-8 in Evaluation Example A-21.
  • 7 is a surface analysis result of an aluminum foil after charge / discharge of a lithium ion secondary battery of Battery A-9 in Evaluation Example A-21.
  • 6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of battery A1 and a response current.
  • 6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of battery A1.
  • 6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of battery A2 and a response current.
  • 6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of battery A2.
  • 6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of a battery A3 and a response current.
  • 6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of a battery A3.
  • 6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of a battery A4 and a response current.
  • 6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of a battery A4.
  • 6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of battery AC1 and a response current.
  • 6 is a graph showing a relationship between a potential (3.0 to 4.5 V) and a response current with respect to a half cell of battery A2.
  • 3 is a graph showing a relationship between a potential (3.0 to 5.0 V) and a response current with respect to a half cell of battery A2.
  • 6 is a graph showing a relationship between a potential (3.0 to 4.5 V) and a response current with respect to a half cell of battery A5.
  • 6 is a graph showing a relationship between a potential (3.0 to 5.0 V) and a response current with respect to a half cell of battery A5.
  • 6 is a graph showing a relationship between a potential (3.0 to 4.5 V) and a response current with respect to a half cell of battery AC2.
  • 3 is a graph showing a relationship between a potential (3.0 to 5.0 V) and a response current with respect to a half cell of battery AC2.
  • the numerical range “a to b” described in this specification includes the lower limit “a” and the upper limit “b”.
  • the numerical range can be configured by arbitrarily combining these upper limit value and lower limit value and the numerical values listed in the examples.
  • numerical values arbitrarily selected from the numerical value range can be used as upper and lower numerical values.
  • the electrolytic solution is an electrolytic solution containing a salt having alkali metal, alkaline earth metal or aluminum as a cation (hereinafter sometimes referred to as “metal salt” or simply “salt”) and an organic solvent having a hetero element.
  • metal salt or simply “salt”
  • organic solvent having a hetero element When the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolytic solution is Io, the peak intensity at the peak wavelength of the organic solvent is Io, and the peak intensity at which the peak of the organic solvent is shifted is Is, Is> Io.
  • the relationship between Is and Io is Is ⁇ Io.
  • an electrolytic solution containing a salt having alkali metal, alkaline earth metal or aluminum as a cation and an organic solvent having a hetero element, the organic solvent having a peak intensity derived from the organic solvent in the vibrational spectrum of the electrolytic solution When the original peak intensity is Io and the peak shifted peak intensity is Is, an electrolyte solution with Is> Io may be referred to as “the electrolyte solution of the present invention”.
  • the metal salt may be a compound that is usually used as an electrolyte, such as LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiAlCl 4 , etc. contained in the battery electrolyte.
  • the cation of the metal salt include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium, and aluminum.
  • the cation of the metal salt is preferably the same metal ion as the charge carrier of the battery using the electrolytic solution.
  • the metal salt cation is preferably lithium.
  • the chemical structure of the anion of the salt may include at least one element selected from halogen, boron, nitrogen, oxygen, sulfur or carbon.
  • Specific examples of the chemical structure of an anion containing halogen or boron include ClO 4 , PF 6 , AsF 6 , SbF 6 , TaF 6 , BF 4 , SiF 6 , B (C 6 H 5 ) 4 , and B (oxalate). 2 , Cl, Br, and I.
  • the chemical structure of the anion of the salt is preferably a chemical structure represented by the following general formula (1), general formula (2), or general formula (3).
  • (R 1 X 1 ) (R 2 X 2 ) N General formula (1) (R 1 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent.
  • An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
  • R 2 represents hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent.
  • the R 1 and R 2 may be bonded to each other to form a ring.
  • X 2 is, SO 2
  • R a , R b , R c , and R d are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a substituent.
  • R a , R b , R c , and R d may be bonded to R 1 or R 2 to form a ring.
  • R 3 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent.
  • An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
  • R e and R f are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a group that may be substituted with a substituent.
  • R e and R f may combine with R 3 to form a ring.
  • Y is selected from O and S.
  • R 4 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent.
  • An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
  • R 5 represents hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent.
  • the R 6 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent.
  • any two or three of R 4 , R 5 and R 6 may be bonded to form a ring.
  • R g , R h , R i , R j , R k , and R l are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, or a cycloalkyl that may be substituted with a substituent.
  • an unsaturated alkyl group that may be substituted with a substituent an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, or a substituent that is substituted with a substituent
  • R g , R h , R i , R j , R k , and R l may combine with R 4 , R 5, or R 6 to form a ring.
  • the term “may be substituted with a substituent” in the chemical structures represented by the general formulas (1) to (3) will be described.
  • an alkyl group that may be substituted with a substituent an alkyl group in which one or more of the hydrogens of the alkyl group are substituted with a substituent, or an alkyl group that does not have a particular substituent Means.
  • substituents in the phrase “may be substituted with a substituent” include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an unsaturated cycloalkyl group, an aromatic group, a heterocyclic group, a halogen, and OH.
  • the chemical structure of the anion of the salt is more preferably a chemical structure represented by the following general formula (4), general formula (5), or general formula (6).
  • R 7 and R 8 are each independently C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h .
  • X 7 is, SO 2
  • C O
  • C S
  • R m P O
  • R n P S
  • S O
  • Si O.
  • R m , R n , R o , and R p are each independently substituted with hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a substituent.
  • R m , R n , R o , and R p may combine with R 7 or R 8 to form a ring.
  • R 9 X 9 Y General formula (5)
  • R 9 is a C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h.
  • R q and R r are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a group that may be substituted with a substituent.
  • R q and R r may combine with R 9 to form a ring.
  • Y is selected from O and S.
  • R 10 , R 11 , and R 12 are each independently C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h .
  • R s , R t , R u , R v , R w , and R x are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, or a cycloalkyl that may be substituted with a substituent.
  • an unsaturated alkyl group that may be substituted with a substituent an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, or a substituent that is substituted with a substituent
  • R s , R t , R u , R v , R w , and R x may combine with R 10 , R 11, or R 12 to form a ring.
  • the meaning of the phrase “may be substituted with a substituent” in the chemical structures represented by the general formulas (4) to (6) has been explained in the general formulas (1) to (3). Is synonymous with In the chemical structures represented by the general formulas (4) to (6), n is preferably an integer of 0 to 6, more preferably an integer of 0 to 4, and particularly preferably an integer of 0 to 2.
  • n is preferably an integer of 1 to 8, more preferably an integer of 1 to 7, and particularly preferably an integer of 1 to 3.
  • n is preferably an integer of 0 to 6, more preferably an integer of 0 to 4, and particularly preferably an integer of 0 to 2.
  • n is preferably an integer of 1 to 8, more preferably an integer of 1 to 7, and particularly preferably an integer of 1 to 3.
  • the metal salt is (CF 3 SO 2 ) 2 NLi (hereinafter sometimes referred to as “LiTFSA”), (FSO 2 ) 2 NLi (hereinafter sometimes referred to as “LiFSA”), (C 2 F 5 SO 2 ) 2 NLi, FSO 2 (CF 3 SO 2 ) NLi, (SO 2 CF 2 CF 2 SO 2 ) NLi, (SO 2 CF 2 CF 2 SO 2 ) NLi, FSO 2 (CH 3 SO 2 ) NLi FSO 2 (C 2 F 5 SO 2 ) NLi or FSO 2 (C 2 H 5 SO 2 ) NLi is particularly preferred.
  • the metal salt of the present invention may be a combination of an appropriate number of cations and anions described above.
  • One kind of metal salt in the electrolytic solution of the present invention may be used, or a plurality of kinds may be used in combination.
  • organic solvent having a hetero element an organic solvent in which the hetero element is at least one selected from nitrogen, oxygen, sulfur and halogen is preferable, and an organic solvent in which the hetero element is at least one selected from nitrogen or oxygen Is more preferable.
  • organic solvent having a hetero element an aprotic solvent having no proton donating group such as NH group, NH 2 group, OH group, and SH group is preferable.
  • organic solvent having a hetero element examples include nitriles such as acetonitrile, propionitrile, acrylonitrile, malononitrile, 1,2-dimethoxyethane, 1, 2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 2,2-dimethyl-1,3-dioxolane, 2-methyltetrahydropyran, 2-methyltetrahydrofuran, crown Ethers such as ether, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolide Amides such as isopropyl isocyanate, n-propyl isocyanate, chloromethyl
  • Esters glycidyl methyl ether, epoxy butane, epoxy such as 2-ethyloxirane, oxazole, 2-ethyloxazole, oxazoline, oxazole such as 2-methyl-2-oxazoline, ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone Acid anhydrides such as acetic anhydride and propionic anhydride, sulfones such as dimethyl sulfone and sulfolane, sulfoxides such as dimethyl sulfoxide, 1-nitropropane and 2-nitrate Nitros such as propane, furans such as furan and furfural, cyclic esters such as ⁇ -butyrolactone, ⁇ -valerolactone and ⁇ -valerolactone, aromatic heterocycles such as thiophene and pyridine, tetrahydro-4-pyrone, Examples thereof include heterocyclic rings such as 1-methylpyr
  • Examples of the organic solvent include chain carbonates represented by the following general formula (10).
  • n is preferably an integer of 1 to 6, more preferably an integer of 1 to 4, and particularly preferably an integer of 1 to 2.
  • m is preferably an integer of 3 to 8, more preferably an integer of 4 to 7, and particularly preferably an integer of 5 to 6.
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • EMC ethylmethyl Carbonate
  • organic solvent a solvent having a relative dielectric constant of 20 or more or a donor ether oxygen is preferable.
  • organic solvent examples include nitriles such as acetonitrile, propionitrile, acrylonitrile, and malononitrile, and 1,2-dimethoxyethane.
  • 1,2-diethoxyethane tetrahydrofuran, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 2,2-dimethyl-1,3-dioxolane, 2-methyltetrahydropyran, 2-methyl Mention may be made of ethers such as tetrahydrofuran and crown ether, N, N-dimethylformamide, acetone, dimethyl sulfoxide and sulfolane, and in particular acetonitrile (hereinafter sometimes referred to as “AN”), 1,2-dimethoxyethane. (Hereafter referred to as “DME”) ) Is preferable. These organic solvents may be used alone in the electrolytic solution, or a plurality of them may be used in combination.
  • the peak intensity derived from the organic solvent contained in the electrolyte solution is denoted by Io, and the peak of the organic solvent inherent peak is shifted (hereinafter, “ If the intensity of “shift peak” is sometimes referred to as “Is”, Is> Io. That is, in the vibrational spectral spectrum chart obtained by subjecting the electrolytic solution of the present invention to vibrational spectral measurement, the relationship between the two peak intensities is Is> Io.
  • the original peak of the organic solvent means a peak observed at the peak position (wave number) when vibration spectroscopy measurement is performed only on the organic solvent.
  • the value of the peak intensity Io inherent in the organic solvent and the value of the shift peak intensity Is are the height or area from the baseline of each peak in the vibrational spectrum.
  • the relationship when there are a plurality of peaks in which the original peak of the organic solvent is shifted, the relationship may be determined based on the peak from which the relationship between Is and Io is most easily determined.
  • an organic solvent that can determine the relationship between Is and Io most easily is selected, an organic solvent that can determine the relationship between Is and Io most easily (the difference between Is and Io is most pronounced) is selected, The relationship between Is and Io may be determined based on the peak intensity. If the peak shift amount is small and the peaks before and after the shift appear to be a gentle mountain, peak separation may be performed using known means to determine the relationship between Is and Io.
  • the peak of an organic solvent that is most easily coordinated with a cation (hereinafter sometimes referred to as “preferred coordination solvent”) is another. Shift in preference to.
  • the mass% of the preferential coordination solvent with respect to the entire organic solvent having a hetero element is preferably 40% or more, more preferably 50% or more, and further preferably 60% or more. 80% or more is particularly preferable.
  • the volume% of the preferential coordination solvent with respect to the entire organic solvent having a hetero element is preferably 40% or more, more preferably 50% or more, and 60% or more. Is more preferable, and 80% or more is particularly preferable.
  • the relationship between the two peak intensities in the vibrational spectrum of the electrolytic solution of the present invention preferably satisfies the condition of Is> 2 ⁇ Io, more preferably satisfies the condition of Is> 3 ⁇ Io, and Is> 5 ⁇ It is more preferable that the condition of Io is satisfied, and it is particularly preferable that the condition of Is> 7 ⁇ Io is satisfied.
  • Most preferred is an electrolytic solution in which the intensity Io of the peak inherent in the organic solvent is not observed and the intensity Is of the shift peak is observed in the vibrational spectrum of the electrolytic solution of the present invention. In the electrolytic solution, it means that all the molecules of the organic solvent contained in the electrolytic solution are completely solvated with the metal salt.
  • the metal salt and the organic solvent (or preferential coordination solvent) having a hetero element have an interaction.
  • a metal salt and a hetero element of an organic solvent (or preferential coordination solvent) having a hetero element form a coordination bond
  • the organic salt (or preferential coordinating solvent) having a metal salt and a hetero element ) Is estimated to form a stable cluster. From the results of evaluation examples described later, this cluster is presumed to be formed by coordination of two molecules of an organic solvent (or preferential coordination solvent) having a hetero element to one molecule of a metal salt.
  • the molar range of the organic solvent having a hetero element (or preferential coordination solvent) with respect to 1 mol of the metal salt in the electrolytic solution of the present invention is preferably 1.4 mol or more and less than 3.5 mol. More preferably, it is 0.5 mol or more and 3.1 mol or less, and 1.6 mol or more and 3 mol or less are still more preferable.
  • the electrolytic solution of the present invention it is presumed that clusters are generally formed by coordination of two molecules of an organic solvent (or preferential coordination solvent) having a hetero element to one molecule of a metal salt.
  • concentration (mol / L) of the electrolytic solution of the invention depends on the molecular weight of each of the metal salt and the organic solvent and the density when the solution is used. Therefore, it is not appropriate to prescribe the concentration of the electrolytic solution of the present invention.
  • the concentration c (mol / L) of the electrolytic solution of the present invention is individually exemplified in Table 1.
  • the organic solvent that forms the cluster and the organic solvent that is not involved in the formation of the cluster have different environments. Therefore, in vibrational spectroscopy measurement, the peak derived from the organic solvent forming the cluster is higher than the observed wave number of the peak derived from the organic solvent not involved in the cluster formation (original peak of the organic solvent). Or it is observed shifted to the low wavenumber side. That is, the shift peak corresponds to the peak of the organic solvent forming the cluster.
  • vibrational spectrum examples include an IR spectrum and a Raman spectrum.
  • measurement method for IR measurement examples include transmission measurement methods such as Nujol method and liquid film method, and reflection measurement methods such as ATR method.
  • transmission measurement methods such as Nujol method and liquid film method
  • reflection measurement methods such as ATR method.
  • IR measurement may be performed under low humidity or no humidity conditions such as a dry room or a glove box, or Raman measurement may be performed with the electrolyte solution in a sealed container.
  • LiTFSA is dissolved in an acetonitrile solvent at a concentration of 1 mol / L to obtain an electrolytic solution according to conventional technical common sense. Since 1 L of acetonitrile corresponds to about 19 mol, 1 L of conventional electrolyte includes 1 mol of LiTFSA and 19 mol of acetonitrile. Then, in the conventional electrolyte, there are many acetonitriles that are not solvated with LiTFSA (not coordinated with Li) simultaneously with acetonitrile that is solvated with LiTFSA (coordinated with Li). .
  • the acetonitrile molecule is different between the LiTFSA solvated acetonitrile molecule and the LiTFSA non-solvated acetonitrile molecule, in the IR spectrum, the acetonitrile peaks of both are distinguished and observed. Is done. More specifically, the peak of acetonitrile that is not solvated with LiTFSA is observed at the same position (wave number) as in the case of IR measurement of only acetonitrile, but the peak of acetonitrile that is solvated with LiTFSA. Is observed with the peak position (wave number) shifted to the high wave number side.
  • the electrolytic solution of the present invention has a higher LiTFSA concentration than the conventional electrolytic solution, and the number of acetonitrile molecules solvated with LiTFSA (forming clusters) in the electrolytic solution is different from that of LiTFSA. More than the number of unsolvated acetonitrile molecules. Then, the relation between the intensity Io of the original peak of the acetonitrile and the intensity Is of the peak obtained by shifting the original peak of acetonitrile in the vibrational spectrum of the electrolytic solution of the present invention is Is> Io.
  • Table 2 exemplifies wave numbers of organic solvents that are considered useful for the calculation of Io and Is in the vibrational spectrum of the electrolytic solution of the present invention, and their attribution. It should be added that the wave number of the observed peak may be different from the following wave numbers depending on the measurement apparatus, measurement environment, and measurement conditions of the vibrational spectrum.
  • the electrolytic solution of the present invention is different from the conventional electrolytic solution in that the presence environment of the metal salt and the organic solvent is different and the concentration of the metal salt is high, so that the metal ion transport rate in the electrolytic solution is improved (especially metal When Li is lithium, the lithium transport number is improved), the reaction rate between the electrode and the electrolyte solution is improved, the uneven distribution of the salt concentration of the electrolyte solution that occurs during high-rate charge / discharge of the battery, and the electric double layer capacity can be expected to increase . Furthermore, in the electrolytic solution of the present invention, since most of the organic solvent having a hetero element forms a cluster with a metal salt, the vapor pressure of the organic solvent contained in the electrolytic solution is lowered. As a result, volatilization of the organic solvent from the electrolytic solution of the present invention can be reduced.
  • the electrolyte of the present invention has a higher viscosity than the conventional battery electrolyte. Therefore, if it is a battery using the electrolyte solution of this invention, even if a battery is damaged, electrolyte solution leakage is suppressed. Moreover, the capacity
  • the capacity of the secondary battery using the electrolytic solution of the present invention is suitably maintained during high-speed charge / discharge. It is considered that the uneven distribution of Li concentration in the electrolytic solution could be suppressed due to the physical properties of the electrolytic solution of the present invention with high viscosity.
  • the high viscosity of the electrolyte solution of the present invention due to the high viscosity of the electrolyte solution of the present invention, the liquid retention of the electrolyte solution at the electrode interface is improved, and the state where the electrolyte solution is insufficient at the electrode interface (so-called liquid withdrawn state) can also be suppressed. This is considered to be one of the reasons that the capacity decrease during the charge / discharge cycle is suppressed.
  • a range of 10 ⁇ ⁇ 500 is preferable, a range of 12 ⁇ ⁇ 400 is more preferable, a range of 15 ⁇ ⁇ 300 is further preferable, and 18 A range of ⁇ ⁇ 150 is particularly preferable, and a range of 20 ⁇ ⁇ 140 is most preferable.
  • the ion conductivity ⁇ (mS / cm) of the electrolytic solution of the present invention is preferably 1 ⁇ ⁇ .
  • a suitable range including the upper limit when a suitable range including the upper limit is shown, a range of 2 ⁇ ⁇ 200 is preferable, and a range of 3 ⁇ ⁇ 100 is more preferable.
  • the range of 4 ⁇ ⁇ 50 is more preferable, and the range of 5 ⁇ ⁇ 35 is particularly preferable.
  • the electrolytic solution of the present invention contains a metal salt cation in a high concentration.
  • the distance between adjacent cations is extremely short.
  • a cation such as lithium ion moves between the positive electrode and the negative electrode during charge / discharge of the secondary battery
  • the cation closest to the destination electrode is first supplied to the electrode.
  • the other cation adjacent to the said cation moves to the place with the said supplied cation.
  • the density d (g / cm 3 ) in the electrolytic solution of the present invention is preferably d ⁇ 1.2 or d ⁇ 2.2, more preferably 1.2 ⁇ d ⁇ 2.2.
  • a range of 24 ⁇ d ⁇ 2.0 is more preferable, a range of 1.26 ⁇ d ⁇ 1.8 is more preferable, and a range of 1.27 ⁇ d ⁇ 1.6 is particularly preferable.
  • the density d (g / cm 3 ) in the electrolytic solution of the present invention means the density at 20 ° C.
  • D / c obtained by dividing the density d (g / cm 3 ) of the electrolytic solution in the electrolytic solution of the present invention by the concentration c (mol / L) of the electrolytic solution is in the range of 0.15 ⁇ d / c ⁇ 0.71.
  • 0.15 ⁇ d / c ⁇ 0.56 more preferably in the range of 0.25 ⁇ d / c ⁇ 0.56, and 0.26 ⁇ d / c ⁇ 0.50.
  • Within the range is more preferable, and within the range of 0.27 ⁇ d / c ⁇ 0.47 is particularly preferable.
  • D / c in the electrolytic solution of the present invention can be defined even when a metal salt and an organic solvent are specified.
  • d / c is preferably within the range of 0.42 ⁇ d / c ⁇ 0.56, and 0.44 ⁇ d / c ⁇ 0.52 The range of is more preferable.
  • d / c is preferably in the range of 0.35 ⁇ d / c ⁇ 0.41, and 0.36 ⁇ d / c ⁇ 0.39. The inside is more preferable.
  • d / c is preferably in the range of 0.32 ⁇ d / c ⁇ 0.46, and in the range of 0.34 ⁇ d / c ⁇ 0.42. The inside is more preferable.
  • d / c is preferably in the range of 0.25 ⁇ d / c ⁇ 0.31, and in the range of 0.26 ⁇ d / c ⁇ 0.29. The inside is more preferable.
  • d / c is preferably in the range of 0.32 ⁇ d / c ⁇ 0.48, and in the range of 0.32 ⁇ d / c ⁇ 0.46.
  • the inside is preferable, and the inside of the range of 0.34 ⁇ d / c ⁇ 0.42 is more preferable.
  • d / c is preferably in the range of 0.34 ⁇ d / c ⁇ 0.50, and in the range of 0.37 ⁇ d / c ⁇ 0.45. The inside is more preferable.
  • d / c is preferably in the range of 0.36 ⁇ d / c ⁇ 0.54, and in the range of 0.39 ⁇ d / c ⁇ 0.48.
  • the inside is more preferable.
  • the method for producing the electrolytic solution of the present invention will be described. Since the electrolytic solution of the present invention has a higher metal salt content than the conventional electrolytic solution, the production method in which an organic solvent is added to a solid (powder) metal salt results in the formation of aggregates. It is difficult to produce an electrolytic solution. Therefore, in the manufacturing method of the electrolyte solution of this invention, it is preferable to manufacture, adding a metal salt gradually with respect to an organic solvent, and maintaining the solution state of electrolyte solution.
  • the electrolytic solution of the present invention includes a liquid in which the metal salt is dissolved in the organic solvent beyond the conventionally considered saturation solubility.
  • a method for producing an electrolytic solution of the present invention includes a first dissolution step of preparing a first electrolytic solution by mixing an organic solvent having a hetero element and a metal salt, dissolving the metal salt, stirring and / or Alternatively, a metal salt is added to the first electrolytic solution under heating conditions to dissolve the metal salt to prepare a supersaturated second electrolytic solution, and a second electrolysis under stirring and / or heating conditions. A metal salt is added to the solution to dissolve the metal salt, and a third dissolution step of preparing a third electrolytic solution is included.
  • the “supersaturated state” means a state in which metal salt crystals are precipitated from the electrolyte when the stirring and / or heating conditions are canceled or when crystal nucleation energy such as vibration is applied. Means.
  • the second electrolytic solution is “supersaturated”, and the first electrolytic solution and the third electrolytic solution are not “supersaturated”.
  • the above-described method for producing the electrolytic solution of the present invention is a thermodynamically stable liquid state, and passes through the first electrolytic solution containing the conventional metal salt concentration, and then the thermodynamically unstable liquid state.
  • the second electrolytic solution passes through the two electrolytic solutions and becomes a thermodynamically stable new electrolytic third solution, that is, the electrolytic solution of the present invention.
  • the third electrolyte solution is composed of, for example, two molecules of an organic solvent for one lithium salt molecule, and a strong distribution between these molecules. It is presumed that the cluster stabilized by the coordinate bond inhibits the crystallization of the lithium salt.
  • the first dissolution step is a step of preparing a first electrolytic solution by mixing an organic solvent having a hetero atom and a metal salt to dissolve the metal salt.
  • a metal salt may be added to the organic solvent having a heteroatom, or an organic solvent having a heteroatom may be added to the metal salt.
  • the first dissolution step is preferably performed under stirring and / or heating conditions. What is necessary is just to set suitably about stirring speed. About heating conditions, it is preferable to control suitably with thermostats, such as a water bath or an oil bath. Since heat of dissolution is generated when the metal salt is dissolved, it is preferable to strictly control the temperature condition when using a metal salt that is unstable to heat. In addition, the organic solvent may be cooled in advance, or the first dissolution step may be performed under cooling conditions.
  • the first dissolution step and the second dissolution step may be performed continuously, or the first electrolytic solution obtained in the first dissolution step is temporarily stored (standing), and after a certain time has passed, You may implement a melt
  • the second dissolution step is a step of preparing a supersaturated second electrolyte solution by adding a metal salt to the first electrolyte solution under stirring and / or heating conditions to dissolve the metal salt.
  • the stirring condition may be achieved, or the second dissolution step is performed using a stirrer and a device (stirrer) that operates the stirrer.
  • the stirring condition may be used.
  • Heating conditions it is preferable to control suitably with thermostats, such as a water bath or an oil bath.
  • thermostats such as a water bath or an oil bath.
  • the warming said by the manufacturing method of electrolyte solution refers to warming a target object to the temperature more than normal temperature (25 degreeC).
  • the heating temperature is more preferably 30 ° C. or higher, and further preferably 35 ° C. or higher. Further, the heating temperature is preferably lower than the boiling point of the organic solvent.
  • the added metal salt is not sufficiently dissolved, increase the stirring speed and / or further heating.
  • a small amount of an organic solvent having a hetero atom may be added to the electrolytic solution in the second dissolution step.
  • the second dissolution step and the third dissolution step are preferably carried out continuously.
  • the third dissolution step is a step of preparing a third electrolyte solution by adding a metal salt to the second electrolyte solution under stirring and / or heating conditions to dissolve the metal salt.
  • it is necessary to add a metal salt to the supersaturated second electrolytic solution and dissolve it. Therefore, it is essential to perform the stirring and / or heating conditions as in the second dissolution step. Specific stirring and / or heating conditions are the same as those in the second dissolution step.
  • the third electrolytic solution (the electrolytic solution of the present invention) can be manufactured. finish. Even when the stirring and / or heating conditions are canceled, the metal salt crystals are not precipitated from the electrolytic solution of the present invention.
  • the electrolytic solution of the present invention is composed of, for example, two molecules of an organic solvent for one molecule of a lithium salt, and is presumed to form a cluster stabilized by a strong coordinate bond between these molecules. Is done.
  • the first to third dissolving steps can be performed even if the supersaturated state is not passed at the treatment temperature in each dissolving step.
  • the electrolytic solution of the present invention can be appropriately produced using the specific dissolution means described in 1.
  • a vibrational spectroscopic measurement step of performing vibrational spectroscopic measurement of the electrolytic solution being manufactured for example, a method of sampling a part of each electrolytic solution in the middle of production and using it for vibration spectroscopic measurement, or a method of performing spectroscopic spectroscopic measurement of each electrolytic solution in situ (situ) But it ’s okay.
  • a method for in-vitro vibrational spectroscopic measurement of an electrolytic solution a method of introducing an electrolytic solution in the middle of production into a transparent flow cell and performing vibrational spectroscopic measurement, or a method of performing Raman measurement from outside the container using a transparent production vessel can be mentioned. Since the relationship between Is and Io in the electrolytic solution can be confirmed during the production by including the vibrational spectroscopic measurement step in the method for producing the electrolytic solution of the present invention, whether the electrolytic solution during the production reaches the electrolytic solution of the present invention. It is possible to determine whether or not the amount of metal salt added to reach the electrolytic solution of the present invention when the electrolytic solution being manufactured does not reach the electrolytic solution of the present invention. can do.
  • the solvent in addition to the organic solvent having a hetero element, the solvent has a low polarity (low dielectric constant) or a low donor number and does not exhibit a special interaction with the metal salt, that is, the present invention.
  • a solvent that does not affect the formation and maintenance of the clusters in the electrolyte can be added.
  • the solvent that does not exhibit a special interaction with the metal salt include benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, 1-methylnaphthalene, hexane, heptane, and cyclohexane. it can.
  • a flame retardant solvent can be added to the electrolytic solution of the present invention.
  • a flame retardant solvent include halogen solvents such as carbon tetrachloride, tetrachloroethane, and hydrofluoroether, and phosphoric acid derivatives such as trimethyl phosphate and triethyl phosphate.
  • the electrolytic solution of the present invention when the electrolytic solution of the present invention is mixed with a polymer or an inorganic filler to form a mixture, the mixture contains the electrolytic solution and becomes a pseudo solid electrolyte.
  • the pseudo-solid electrolyte As the battery electrolyte, leakage of the electrolyte in the battery can be suppressed.
  • a polymer used for a battery such as a lithium ion secondary battery or a general chemically crosslinked polymer can be employed.
  • a polymer that can absorb an electrolyte such as polyvinylidene fluoride and polyhexafluoropropylene and gel can be used, and a polymer such as polyethylene oxide in which an ion conductive group is introduced.
  • polymers include polymethyl acrylate, polymethyl methacrylate, polyethylene oxide, polypropylene oxide, polyacrylonitrile, polyvinylidene fluoride, polyethylene glycol dimethacrylate, polyethylene glycol acrylate, polyglycidol, polytetrafluoroethylene, polyhexafluoropropylene, Polycarboxylic acid such as polysiloxane, polyvinyl acetate, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyitaconic acid, polyfumaric acid, polycrotonic acid, polyangelic acid, carboxymethylcellulose, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene , Polycarbonate, unsaturated polyester copolymerized with maleic anhydride and glycols, Polyethylene oxide derivative having a group, a copolymer of vinylidene fluoride and hexafluoropropylene can be exempl
  • Polysaccharides are also suitable as the polymer.
  • Specific examples of the polysaccharide include glycogen, cellulose, chitin, agarose, carrageenan, heparin, hyaluronic acid, pectin, amylopectin, xyloglucan, and amylose.
  • adopt the material containing these polysaccharides as said polymer The agar containing polysaccharides, such as agarose, can be illustrated as the said material.
  • the inorganic filler is preferably an inorganic ceramic such as oxide or nitride.
  • Inorganic ceramics have hydrophilic and hydrophobic functional groups on the surface. Therefore, when the functional group attracts the electrolytic solution, a conductive path can be formed in the inorganic ceramic. Furthermore, the inorganic ceramics dispersed in the electrolytic solution can form a network between the inorganic ceramics by the functional groups and serve to contain the electrolytic solution. With such a function of the inorganic ceramics, it is possible to more suitably suppress the leakage of the electrolytic solution in the battery. In order to suitably exhibit the above functions of the inorganic ceramics, the inorganic ceramics preferably have a particle shape, and particularly preferably have a particle size of nano level.
  • the inorganic ceramics include general alumina, silica, titania, zirconia, and lithium phosphate. Further, the inorganic ceramic itself may be lithium conductive, and specifically, Li 3 N, LiI, LiI—Li 3 N—LiOH, LiI—Li 2 S—P 2 O 5 , LiI—Li 2 S —P 2 S 5 , LiI—Li 2 S—B 2 S 3 , Li 2 O—B 2 S 3 , Li 2 O—V 2 O 3 —SiO 2 , Li 2 O—B 2 O 3 —P 2 O 5 , Li 2 O—B 2 O 3 —ZnO, Li 2 O—Al 2 O 3 —TiO 2 —SiO 2 —P 2 O 5 , LiTi 2 (PO 4 ) 3 , Li— ⁇ Al 2 O 3 , LiTaO 3 Can be illustrated.
  • Li 3 N LiI, LiI—Li 3 N—LiOH, LiI—Li 2 S—
  • Glass ceramics may be employed as the inorganic filler. Since glass ceramics can contain an ionic liquid, the same effect can be expected for the electrolytic solution of the present invention. Glass ceramics include a compound represented by xLi 2 S- (1-x) P 2 S 5 , a compound obtained by substituting a part of S of the compound with another element, and a P of the compound. An example in which the part is replaced with germanium can be exemplified.
  • the electrolytic solution of the present invention described above exhibits excellent ionic conductivity, it is suitably used as an electrolytic solution for power storage devices such as batteries.
  • it is preferably used as an electrolyte solution for a secondary battery, and particularly preferably used as an electrolyte solution for a lithium ion secondary battery.
  • an S, O-containing film is formed on the surface of the negative electrode and / or the positive electrode in the nonaqueous electrolyte secondary battery of the present invention.
  • this film contains S and O, and has at least an S ⁇ O structure.
  • the electrolytic solution of the present invention it is considered that the Li cation and the anion are present in the vicinity as compared with a normal electrolytic solution. For this reason, the anion is preferentially reduced and decomposed by being strongly affected by the electrostatic influence from the Li cation.
  • an organic solvent for example, EC: ethylene carbonate
  • an SEI film is formed by a decomposition product of the organic solvent.
  • anions are preferentially reduced and decomposed.
  • the SEI film that is, the S, O-containing film in the non-aqueous electrolyte secondary battery of the present invention contains a lot of S ⁇ O structures derived from anions.
  • an SEI film derived from a decomposition product of an organic solvent such as EC is fixed on the electrode surface.
  • the SEI film mainly derived from the anion of the metal salt is fixed on the electrode surface.
  • the state of the S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention changes with charge / discharge.
  • the S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention is derived from the above-described decomposition product of anions and fixed in the film (hereinafter referred to as a fixing unit as required), It is considered that there is a portion that reversibly increases / decreases with charge / discharge (hereinafter referred to as an adsorption portion as necessary).
  • the adsorption part is presumed to have a structure such as S ⁇ O derived from the anion of the metal salt as in the fixing part.
  • the S, O-containing film is composed of a decomposition product of the electrolytic solution and is thought to contain other adsorbents, most (or all) of the S, O-containing film is the first charge / discharge of the nonaqueous electrolyte secondary battery. It is considered to be generated after the hour. That is, the nonaqueous electrolyte secondary battery of the present invention has an S, O-containing film on the surface of the negative electrode and / or the surface of the positive electrode in use.
  • Other constituent components of the S, O-containing coating are variously different depending on components other than sulfur and oxygen contained in the electrolytic solution, the composition of the negative electrode, and the like.
  • the S, O-containing film may be formed only on the negative electrode surface, or may be formed only on the positive electrode surface. However, as described above, since the S, O-containing film is considered to be derived from the anion of the metal salt contained in the electrolytic solution of the present invention, it contains more components derived from the anion of the metal salt than the other components. preferable.
  • the S, O-containing film is preferably formed on both the negative electrode surface and the positive electrode surface.
  • the S, O-containing film formed on the surface of the negative electrode is referred to as the negative electrode S, O-containing film
  • the S, O-containing film formed on the surface of the positive electrode is referred to as the positive electrode S, O-containing film as necessary.
  • an imide salt can be preferably used as the metal salt in the electrolytic solution of the present invention.
  • a technique for adding an imide salt to an electrolytic solution is known.
  • the coating on the positive electrode and / or the negative electrode is an organic solvent of the electrolytic solution.
  • compounds derived from decomposition products it is known to include compounds derived from imide salts, that is, compounds containing S.
  • a component derived from an imide salt partially contained in this film improves the durability of the nonaqueous electrolyte secondary battery while suppressing an increase in the internal resistance of the nonaqueous electrolyte secondary battery. It has been introduced to get.
  • the conventional electrolyte solution containing an imide salt contains a large amount of cyclic carbonate such as EC as an organic solvent and also contains an imide salt as an additive.
  • the main component of the SEI film is a component derived from an organic solvent, and it is difficult to increase the content of the imide salt of the SEI film.
  • an imide salt is used as a metal salt (that is, an electrolyte salt or a supporting salt) rather than as an additive, it is necessary to consider a combination with a current collector for a positive electrode. That is, imide salts are known to corrode aluminum current collectors that are generally used as current collectors for positive electrodes.
  • the positive electrode which operates at a potential of about 4 V in particular, it is necessary to coexist with an aluminum current collector an electrolytic solution containing LiPF 6 or the like that forms an immobile with aluminum as an electrolyte salt.
  • the total concentration of the electrolyte salt composed of LiPF 6 or imide salt is optimally about 1 mol / L to 2 mol / L from the viewpoint of ionic conductivity and viscosity (Japanese Patent Laid-Open No. 2013-145732). ).
  • the imide salt may be simply abbreviated as a metal salt.
  • the electrolytic solution of the present invention contains a metal salt at a high concentration.
  • the metal salt is present in a state completely different from the conventional one.
  • a problem caused by the high concentration of the metal salt hardly occurs.
  • the electrolytic solution of the present invention it is possible to suppress a decrease in input / output performance of the nonaqueous electrolyte secondary battery due to an increase in the viscosity of the electrolytic solution, and it is also possible to suppress corrosion of the aluminum current collector.
  • the metal salt contained in the electrolytic solution at a high concentration is preferentially reduced and decomposed on the negative electrode.
  • an SEI film having a special structure derived from a metal salt, that is, an S, O-containing film is formed on the negative electrode without using a cyclic carbonate compound such as EC as the organic solvent. Therefore, the nonaqueous electrolyte secondary battery of the present invention can be reversibly charged and discharged without using a cyclic carbonate compound as an organic solvent even when graphite is used as the negative electrode active material.
  • the nonaqueous electrolyte secondary battery of the present invention uses a cyclic carbonate compound as the organic solvent or LiPF as the metal salt even when graphite is used as the negative electrode active material and an aluminum current collector is used as the positive electrode current collector. 6 can be reversibly charged / discharged. Furthermore, most of the SEI film on the negative electrode and / or positive electrode surface can be composed of anion-derived components. As will be described later, the S, O-containing film containing an anion-derived component can improve the battery characteristics of the nonaqueous electrolyte secondary battery.
  • the negative electrode film includes many polymer structures in which carbon derived from the EC solvent is polymerized.
  • the negative electrode S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention contains almost no (or no) polymer structure obtained by polymerizing such carbon, and is derived from an anion of a metal salt. Including many. The same applies to the positive electrode film.
  • the electrolytic solution of the present invention contains a metal salt cation in a high concentration.
  • the distance between adjacent cations is extremely short.
  • cations such as lithium ions move between the positive electrode and the negative electrode during charge / discharge of the nonaqueous electrolyte secondary battery
  • the cations closest to the destination electrode are first supplied to the electrode.
  • the other cation adjacent to the said cation moves to the place with the said supplied cation.
  • the reaction rate of the nonaqueous electrolyte secondary battery of the present invention having the electrolytic solution of the present invention is considered to be high.
  • the nonaqueous electrolyte secondary battery of the present invention has an S, O-containing film on an electrode (that is, a negative electrode and / or a positive electrode), and the S, O-containing film has an S ⁇ O structure and contains many cations. it is conceivable that. It is considered that cations contained in the S, O-containing film are preferentially supplied to the electrode.
  • the cation transport rate is further improved by having an abundant cation source (that is, an S, O-containing film) in the vicinity of the electrode. Therefore, in the nonaqueous electrolyte secondary battery of the present invention, it is considered that excellent battery characteristics are exhibited by the cooperation of the electrolytic solution of the present invention and the S, O-containing film.
  • the SEI film of the negative electrode is constituted by a deposit of the electrolytic solution generated by reductive decomposition of the electrolytic solution at a predetermined voltage or less. That is, in order to efficiently generate the above-described S, O-containing film on the surface of the negative electrode, the non-aqueous electrolyte secondary battery of the present invention should have the minimum value of the negative electrode potential not more than a predetermined value. Specifically, the nonaqueous electrolyte secondary battery of the present invention is suitable as a battery to be used under the condition that the minimum value of the negative electrode potential is 1.3 V or less when the counter electrode is lithium.
  • the maximum use potential of the non-aqueous secondary battery according to the fourth aspect of the present invention is 4.5 V or more when Li / Li + is a reference potential.
  • the “maximum potential used” means the positive electrode potential (Li / Li + reference potential) at the end of charging of the battery controlled within a range that does not cause the collapse of the positive electrode active material. The liquid is not easily decomposed even at a high potential.
  • a lithium metal composite oxide or a polyanionic material that undergoes a charging reaction at a high potential can be used as the positive electrode active material.
  • a lithium metal composite oxide having an average reaction potential of 4.5 V or more can be used as the positive electrode active material.
  • a lithium metal composite oxide having an average reaction potential of less than 4.5V can be charged to a potential of 4.5V or more.
  • the maximum use potential of the positive electrode can be set to 4.5 V or higher, which is higher than the conventional one.
  • the upper limit of the maximum use potential of the positive electrode is described, 6.0 V or 5.7 V can be exemplified.
  • the oxidative decomposition potential of the electrolytic solution is preferably 4.5 V or more on the basis of the Li + / Li electrode. In this case, oxidative decomposition of the electrolytic solution can be suppressed even when the battery is used at a high positive electrode potential of 4.5 V or higher.
  • 6.0 V or 5.7 V can be exemplified.
  • LSV Linear sweep voltammetry
  • the ratio of the increase amount of the current value to the increase amount of the potential is defined as the current increase rate. This increase rate is low immediately after voltage application. When a voltage is applied to a predetermined high potential, the electrolytic solution is oxidatively decomposed, the current increase rate increases rapidly, and current starts to flow.
  • the current-potential curve formed by performing the LSV evaluation has a flat portion from immediately after voltage application until a predetermined potential higher than 4.5 V (vs Li + / Li) is reached.
  • a predetermined potential higher than 4.5 V vs Li + / Li
  • the “rising part” refers to a part of the current-potential curve that has a larger current increase rate than the flat part.
  • the electrolytic solution is oxidatively decomposed and a current flows.
  • the non-aqueous secondary battery of the present invention includes a positive electrode having a positive electrode active material capable of occluding and releasing metal ions such as lithium ions, and a negative electrode having a negative electrode active material capable of occluding and releasing metal ions such as lithium ions, And an electrolytic solution having a metal salt.
  • the positive electrode used for a non-aqueous secondary battery has a positive electrode active material that can occlude and release metal ions.
  • the positive electrode has a current collector and a positive electrode active material layer bound to the surface of the current collector.
  • the positive electrode active material has a lithium metal composite oxide having a layered rock salt structure.
  • a lithium metal composite oxide having a layered rock salt structure is also referred to as a layered compound.
  • the ratio of b: c: d in the general formula is 0.5: 0.2: 0.3, 1/3: 1/3: 1/3, 0.75: 0.10: 0.15. 0: 0: 1, 1: 0: 0, and 0: 1: 0.
  • lithium metal composite oxide having a layered rock salt structure examples include LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , LiNi 0. .5 Mn 0.5 O 2 , LiNi 0.75 Co 0.1 Mn 0.15 O 2 , LiMnO 2 , LiNiO 2 , and LiCoO 2 may be at least one kind.
  • the positive electrode active material may include a solid solution composed of a mixture of a lithium metal composite oxide having a layered rock salt structure and spinel such as LiMn 2 O 4 and Li 2 Mn 2 O 4 . There is Li 2 MnO 3 —LiCoO 2 .
  • Any metal oxide used as the positive electrode active material may have the above composition formula as a basic composition, and a metal element included in the basic composition may be replaced with another metal element, and Mg, etc. Other metal elements may be added to the basic composition to form a metal oxide.
  • the positive electrode active material has a lithium metal composite oxide having a spinel structure.
  • the transition metal element that can constitute A in the general formula is, for example, at least one element selected from Fe, Cr, Cu, Zn, Zr, Ti, V, Mo, Nb, W, La, Ni, and Co. There should be.
  • a specific example of the lithium metal composite oxide is preferably at least one selected from LiMn 2 O 4 and LiNi 0.5 Mn 1.5 O 4 .
  • the lithium metal composite oxide used as the positive electrode active material only needs to have the above composition formula as a basic composition, and can be used in which the metal element contained in the basic composition is replaced with another metal element, such as Mg. Other metal elements may be added to the basic composition to form a metal oxide.
  • the positive electrode active material has a polyanionic material.
  • the polyanion material may be, for example, a polyanion material containing lithium.
  • the polyanionic material containing lithium is a polyanionic compound represented by LiMPO 4 , LiMVO 4 or Li 2 MSiO 4 (wherein M is selected from at least one of Co, Ni, Mn, and Fe). Can be mentioned.
  • polyanion-based material may be at least one selected from LiFePO 4 , Li 2 FeSiO 4 , LiCoPO 4 , Li 2 CoPO 4 , Li 2 MnPO 4 , and Li 2 MnSiO 4 having an olivine structure.
  • the polyanion-based material used as the positive electrode active material may have the above composition formula as a basic composition, and a material obtained by substituting a metal element included in the basic composition with another metal element can be used. These metal elements may be added to the basic composition to form a metal oxide.
  • the positive electrode active material may have a lithium metal composite oxide and / or a polyanion material.
  • the lithium metal composite oxide preferably has a spinel structure.
  • the transition metal element that can constitute A in the general formula is, for example, at least one element selected from Fe, Cr, Cu, Zn, Zr, Ti, V, Mo, Nb, W, La, Ni, and Co. There should be.
  • a specific example of the lithium metal composite oxide is preferably at least one selected from the group consisting of LiMn 2 O 4 and LiNi 0.5 Mn 1.5 O 4 .
  • the lithium metal composite oxide may have a layered rock salt structure together with the spinel structure or instead of the spinel structure.
  • a lithium metal composite oxide having a layered rock salt structure is also referred to as a layered compound.
  • the lithium metal composite oxide may contain a solid solution composed of a mixture of a layered rock salt structure and a spinel such as LiMn 2 O 4 or LiNi 0.5 Mn 1.5 O 4 .
  • the polyanion material may be, for example, a polyanion material containing lithium.
  • the polyanionic material containing lithium is a polyanionic compound represented by LiMPO 4 , LiMVO 4 or Li 2 MSiO 4 (wherein M is selected from at least one of Co, Ni, Mn, and Fe). Can be mentioned.
  • the lithium metal composite oxide and / or the polyanion-based material preferably has a reaction potential of 4.5 V or more on the basis of the Li + / Li electrode.
  • the “reaction potential of the positive electrode active material” refers to a potential at which the positive electrode active material undergoes a reduction reaction upon charging. This reaction potential is based on the Li + / Li electrode.
  • reaction potential may vary somewhat, in this specification, “reaction potential” refers to an average value of reaction potentials having a width. When there are a plurality of reaction potentials, it means an average value among the reaction potentials of the plurality of stages.
  • lithium metal composite oxide and polyanion-based material having a reaction potential of 4.5 V or more on the basis of the Li + / Li electrode examples include LiNi 0.5 Mn 1.5 O 4 (spinel), LiCoPO 4 (polyanion), Li 2 CoPO 4 F (polyanion), Li 2 MnO 3 —LiMO 2 (wherein M is selected from at least one of Co, Ni, Mn, and Fe) (solid solution system having a layered rock salt structure), Li 2 such MnSiO 4 (polyanion) include, but are not limited thereto.
  • the lithium metal composite oxide and the polyanion material may have a reaction potential of less than 4.5 V on the basis of the Li + / Li electrode.
  • a lithium metal complex oxide for example, among those having a layered rock salt structure, LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , at least one selected from LiNi 0.5 Mn 0.5 O 2 , LiNi 0.75 Co 0.1 Mn 0.15 O 2 , LiMnO 2 , LiNiO 2 , and LiCoO 2 .
  • the polyanionic material include at least one selected from LiFePO 4 having an olivine structure and Li 2 FeSiO 4 , but are not limited thereto.
  • FIG. 92 shows a model explanatory diagram of a charging curve of a lithium metal composite oxide and a polyanion material.
  • the lithium metal composite oxide has a solid solution type and a two-phase coexistence type.
  • the solid solution type is a case where the reaction of the active material passes through the solid solution, and as the discharge proceeds, the positive electrode potential gradually decreases, and as the charging proceeds, the potential gradually increases.
  • the two-phase coexistence type when the active material is discharged, the second phase appears, the two phases coexist, there is a region where the positive electrode potential does not decrease even if the discharge proceeds, and there is a region where the potential does not increase even when the charging proceeds. is there.
  • the positive electrode and the electrolytic solution of the present invention may be freely combined.
  • the lithium metal composite oxide used as the positive electrode active material only needs to have the above composition formula as a basic composition, and can be used in which the metal element contained in the basic composition is replaced with another metal element, such as Mg. Other metal elements may be added to the basic composition to form a metal oxide.
  • the non-aqueous secondary battery of the present invention is a non-aqueous battery having a positive electrode having the lithium metal composite oxide or the polyanionic material as a positive electrode active material, a negative electrode having a negative electrode active material, and an electrolyte.
  • the electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal, or aluminum and an organic solvent having a hetero element, and the organic solvent in a vibrational spectrum of the electrolytic solution Assuming that the intensity of the peak derived from the organic solvent is Io and the intensity of the peak shifted from the peak is Is, it is understood that the nonaqueous secondary battery is Is> Io. be able to.
  • the positive electrode current collector is not particularly limited as long as it is a metal that can withstand a voltage suitable for the active material to be used.
  • the current collector refers to a chemically inert electronic high conductor that keeps a current flowing through an electrode during discharging or charging of a non-aqueous secondary battery.
  • As the current collector at least one selected from silver, copper, gold, aluminum, tungsten, cobalt, zinc, nickel, iron, platinum, tin, indium, titanium, ruthenium, tantalum, chromium, molybdenum, and stainless steel, etc. Metal materials can be exemplified.
  • the positive electrode current collector is preferably made of aluminum or an aluminum alloy.
  • aluminum refers to pure aluminum, and aluminum having a purity of 99.0% or more is referred to as pure aluminum.
  • An alloy obtained by adding various elements to pure aluminum is referred to as an aluminum alloy. Examples of the aluminum alloy include Al—Cu, Al—Mn, Al—Fe, Al—Si, Al—Mg, AL—Mg—Si, and Al—Zn—Mg.
  • aluminum or aluminum alloy examples include, for example, A1000 series alloys (pure aluminum series) such as JIS A1085 and A1N30, A3000 series alloys (Al-Mn series) such as JIS A3003 and A3004, JIS A8079, A8021, etc. A8000-based alloy (Al-Fe-based).
  • the current collector When the potential of the positive electrode is 4 V or higher with respect to lithium, it is preferable to employ aluminum as the current collector.
  • the current collector may be covered with a known protective layer. What collected the surface of the electrical power collector by the well-known method may be used as an electrical power collector.
  • the current collector can take the form of a foil, a sheet, a film, a linear shape, a rod shape, a mesh, or the like. Therefore, for example, a metal foil such as a copper foil, a nickel foil, an aluminum foil, and a stainless steel foil can be suitably used as the current collector.
  • a metal foil such as a copper foil, a nickel foil, an aluminum foil, and a stainless steel foil can be suitably used as the current collector.
  • the thickness is preferably in the range of 1 ⁇ m to 100 ⁇ m.
  • the positive electrode active material layer contains a positive electrode active material and, if necessary, a binder and / or a conductive aid.
  • the binder plays a role of connecting the active material and the conductive auxiliary agent to the surface of the current collector.
  • binder examples include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, and alkoxysilyl group-containing resins. be able to.
  • fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber
  • thermoplastic resins such as polypropylene and polyethylene
  • imide resins such as polyimide and polyamideimide
  • alkoxysilyl group-containing resins alkoxysilyl group-containing resins.
  • a polymer having a hydrophilic group may be employed as the binder.
  • the hydrophilic group of the polymer having a hydrophilic group include a phosphate group such as a carboxyl group, a sulfo group, a silanol group, an amino group, a hydroxyl group, and a phosphate group.
  • a polymer containing a carboxyl group in the molecule such as polyacrylic acid (PAA), carboxymethyl cellulose (CMC) and polymethacrylic acid, or a polymer containing a sulfo group such as poly (p-styrenesulfonic acid) is preferable.
  • Polymers containing a large amount of carboxyl groups and / or sulfo groups such as polyacrylic acid or a copolymer of acrylic acid and vinyl sulfonic acid, are water-soluble. Therefore, the polymer having a hydrophilic group is preferably a water-soluble polymer, and a polymer containing a plurality of carboxyl groups and / or sulfo groups in one molecule is preferable.
  • the polymer containing a carboxyl group in the molecule can be produced by, for example, a method of polymerizing an acid monomer or adding a carboxyl group to the polymer.
  • Acid monomers include acrylic acid, methacrylic acid, vinyl benzoic acid, crotonic acid, pentenoic acid, angelic acid, tiglic acid, etc., acid monomers having one carboxyl group in the molecule, itaconic acid, mesaconic acid, citraconic acid, fumaric acid
  • Examples include maleic acid, 2-pentenedioic acid, methylene succinic acid, allyl malonic acid, isopropylidene succinic acid, 2,4-hexadiene diacid, acetylenedicarboxylic acid, and other acid monomers having two or more carboxyl groups in the molecule. Is done. A copolymer obtained by polymerizing two or more kinds of monomers selected from these may be used.
  • a polymer composed of a copolymer of acrylic acid and itaconic acid as described in JP-A-2013-065493, and containing an acid anhydride group formed by condensation of carboxyl groups in the molecule It is also preferable to use as a binder.
  • the structure derived from a highly acidic monomer having two or more carboxyl groups in one molecule is believed to facilitate trapping of metal ions such as lithium ions before the electrolytic solution decomposition reaction occurs during charging.
  • the acidity is not excessively increased because there are more carboxyl groups and the acidity is higher than polyacrylic acid and polymethacrylic acid, and a predetermined amount of the carboxyl groups are changed to acid anhydride groups. Therefore, a secondary battery having a negative electrode formed using this binder has improved initial efficiency and improved input / output characteristics.
  • Conductive aid is added to increase the conductivity of the electrode. Therefore, the conductive auxiliary agent may be added arbitrarily when the electrode conductivity is insufficient, and may not be added when the electrode conductivity is sufficiently excellent.
  • the conductive auxiliary agent may be any chemically inert electronic high conductor, such as carbon black, graphite, acetylene black, ketjen black (registered trademark), or vapor grown carbon fiber (Vapor Grown Carbon). Fiber: VGCF) and various metal particles are exemplified. These conductive assistants can be added to the active material layer alone or in combination of two or more.
  • the negative electrode used in the non-aqueous secondary battery of the present invention has a current collector and a negative electrode active material layer bound to the surface of the current collector.
  • the negative electrode active material layer includes a negative electrode active material and, if necessary, a binder and / or a conductive aid.
  • the binder and conductive additive that may be contained in the negative electrode active material layer may have the same components and composition ratios as the binder and conductive aid that may be contained in the positive electrode active material layer.
  • the negative electrode active material a material that can occlude and release metal ions such as lithium ions can be used. Therefore, there is no particular limitation as long as it is a simple substance, alloy, or compound that can occlude and release metal ions such as lithium ions.
  • a negative electrode active material Li, group 14 elements such as carbon, silicon, germanium and tin, group 13 elements such as aluminum and indium, group 12 elements such as zinc and cadmium, group 15 elements such as antimony and bismuth, magnesium , Alkaline earth metals such as calcium, and group 11 elements such as silver and gold may be employed alone.
  • the negative electrode active material When silicon or the like is used for the negative electrode active material, a silicon atom reacts with a plurality of lithiums, so that it becomes a high-capacity active material. However, there is a problem that volume expansion and contraction due to insertion and extraction of lithium becomes significant. In order to reduce the fear, it is also preferable to employ an alloy or compound in which another element such as a transition metal is combined with a simple substance such as silicon as the negative electrode active material.
  • the alloy or compound include tin-based materials such as Ag—Sn alloy, Cu—Sn alloy and Co—Sn alloy, carbon-based materials such as various graphites, SiO x (disproportionated into silicon simple substance and silicon dioxide).
  • Examples thereof include silicon-based materials such as 0.3 ⁇ x ⁇ 1.6), silicon alone, or composites obtained by combining silicon-based materials and carbon-based materials.
  • a non-aqueous secondary battery using a material capable of inserting and extracting lithium ions as a negative electrode active material and a positive electrode active material is referred to as a lithium ion secondary battery.
  • the negative electrode current collector is not particularly limited as long as it is a metal that can withstand a voltage suitable for the active material to be used, and for example, the one described for the positive electrode current collector can be adopted.
  • the negative electrode binder and the conductive additive those described for the positive electrode can be adopted.
  • an active material layer on the surface of the current collector As a method for forming the active material layer on the surface of the current collector, a conventionally known method such as a roll coating method, a die coating method, a dip coating method, a doctor blade method, a spray coating method, or a curtain coating method is used.
  • An active material may be applied to the surface of the electric body. Specifically, an active material layer-forming composition containing an active material and, if necessary, a binder and a conductive aid is prepared, and an appropriate solvent is added to the composition to make a paste, and then the collection is performed. After applying to the surface of the electric body, it is dried. Examples of the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, and water. In order to increase the electrode density, the dried product may be compressed.
  • a separator is used for non-aqueous secondary batteries as necessary.
  • the separator separates the positive electrode and the negative electrode and allows metal ions such as lithium ions to pass while preventing a short circuit of current due to contact between the two electrodes.
  • natural resins such as polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamide, polyaramid (Aromatic polymer), polyester, polyacrylonitrile, etc., polysaccharides such as cellulose, amylose, fibroin, keratin, lignin, suberin, etc. Examples thereof include porous bodies, nonwoven fabrics, and woven fabrics using one or more electrically insulating materials such as polymers and ceramics.
  • the separator may have a multilayer structure.
  • the electrolytic solution has a slightly high viscosity and a high polarity
  • a membrane in which a polar solvent such as water can easily penetrate is preferable.
  • a film in which a polar solvent such as water soaks into 90% or more of the existing voids is more preferable.
  • a separator is sandwiched between the positive electrode and the negative electrode as necessary to form an electrode body.
  • the electrode body may be either a stacked type in which the positive electrode, the separator and the negative electrode are stacked, or a wound type in which the positive electrode, the separator and the negative electrode are sandwiched.
  • the shape of the non-aqueous secondary battery of the present invention is not particularly limited, and various shapes such as a cylindrical shape, a square shape, a coin shape, and a laminate shape can be adopted.
  • the non-aqueous secondary battery of the present invention may be mounted on a vehicle.
  • the vehicle may be a vehicle that uses electric energy from a non-aqueous secondary battery for all or a part of its power source.
  • the vehicle may be an electric vehicle or a hybrid vehicle.
  • a non-aqueous secondary battery is mounted on a vehicle, a plurality of non-aqueous secondary batteries may be connected in series to form an assembled battery.
  • the non-aqueous secondary battery include various home electric appliances, office equipment, industrial equipment, and the like that are driven by batteries, such as personal computers and portable communication devices, in addition to vehicles.
  • non-aqueous secondary battery of the present invention includes wind power generation, solar power generation, hydroelectric power generation and other power system power storage devices and power smoothing devices, power of ships and / or power supply sources of auxiliary machinery, aircraft, Power supply for spacecraft and / or auxiliary equipment, auxiliary power supply for vehicles that do not use electricity as a power source, power supply for mobile home robots, power supply for system backup, power supply for uninterruptible power supply, You may use for the electrical storage apparatus which stores temporarily the electric power required for charge in the charging station for electric vehicles.
  • Example A-No. Comparative Example A-No.
  • Battery B-No. Comparative Example B-No.
  • the obtained electrolytic solution had a volume of 20 mL, and (CF 3 SO 2 ) 2 NLi contained in this electrolytic solution was 18.38 g.
  • the concentration of (CF 3 SO 2 ) 2 NLi in the electrolytic solution E1 was 3.2 mol / L.
  • the production was performed in a glove box under an inert gas atmosphere.
  • Electrolytic solution E2 Using 16.08 g of (CF 3 SO 2 ) 2 NLi, an electrolytic solution E2 having a concentration of (CF 3 SO 2 ) 2 NLi of 2.8 mol / L was produced in the same manner as the electrolytic solution E1. In the electrolytic solution E2, 2.1 molecules of 1,2-dimethoxyethane are contained per molecule of (CF 3 SO 2 ) 2 NLi.
  • Electrolytic solution E3 About 5 mL of acetonitrile, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (CF 3 SO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in acetonitrile in the flask. When 19.52 g of (CF 3 SO 2 ) 2 NLi was added in total, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and acetonitrile was added until the volume was 20 mL. This was designated as an electrolytic solution E3. The production was performed in a glove box under an inert gas atmosphere.
  • the concentration of (CF 3 SO 2 ) 2 NLi in the electrolytic solution E3 was 3.4 mol / L.
  • 3 molecules of acetonitrile are contained with respect to 1 molecule of (CF 3 SO 2 ) 2 NLi.
  • Electrolytic solution E4 Using 24.11 g of (CF 3 SO 2 ) 2 NLi, an electrolytic solution E4 having a concentration of (CF 3 SO 2 ) 2 NLi of 4.2 mol / L was produced in the same manner as the electrolytic solution E3. In the electrolytic solution E4, 1.9 molecules of acetonitrile are contained with respect to (CF 3 SO 2 ) 2 NLi1 molecules.
  • Electrolytic solution E5 Using (FSO 2) 2 NLi of 13.47g lithium salt, except for using 1,2-dimethoxyethane as the organic solvent, in the same manner as the electrolyte solution E3, (FSO 2) concentration of 2 NLi 3 An electrolytic solution E5 having a concentration of 6 mol / L was produced. In the electrolytic solution E5, 1.9 molecules of 1,2-dimethoxyethane are contained per 1 molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E6 (Electrolytic solution E6) Using 14.97 g of (FSO 2 ) 2 NLi, an electrolytic solution E6 having a concentration of (FSO 2 ) 2 NLi of 4.0 mol / L was produced in the same manner as the electrolytic solution E5. In the electrolytic solution E6, 1.5 molecules of 1,2-dimethoxyethane are contained per 1 molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E7 having a concentration of 4.2 mol / L of (FSO 2 ) 2 NLi was produced in the same manner as the electrolytic solution E3 except that 15.72 g of (FSO 2 ) 2 NLi was used as the lithium salt. .
  • electrolytic solution E7 3 molecules of acetonitrile are contained with respect to 1 molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E8 having a concentration of (FSO 2 ) 2 NLi of 4.5 mol / L was produced in the same manner as the electrolytic solution E7 using 16.83 g of (FSO 2 ) 2 NLi.
  • electrolytic solution E8 2.4 molecules of acetonitrile are contained with respect to (FSO 2 ) 2 NLi1 molecules.
  • Electrolytic solution E9 An electrolyte solution E9 having a concentration of (FSO 2 ) 2 NLi of 5.0 mol / L was produced using 18.71 g of (FSO 2 ) 2 NLi in the same manner as the electrolyte solution E7. In the electrolytic solution E9, 2.1 molecules of acetonitrile are contained with respect to (FSO 2 ) 2 NLi1 molecules.
  • Electrolytic solution E10 (Electrolytic solution E10) Using 20.21 g of (FSO 2 ) 2 NLi, an electrolytic solution E10 having a concentration of (FSO 2 ) 2 NLi of 5.4 mol / L was produced in the same manner as the electrolytic solution E7. In the electrolyte solution E10, 2 molecules of acetonitrile are contained with respect to 1 molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E11 About 5 mL of dimethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to dimethyl carbonate in the flask and dissolved. When (FSO 2 ) 2 NLi was added in a total amount of 14.64 g, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and dimethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution E11. The production was performed in a glove box under an inert gas atmosphere.
  • the concentration of (FSO 2 ) 2 NLi in the electrolytic solution E11 was 3.9 mol / L.
  • two molecules of dimethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E12 Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E12 having a (FSO 2 ) 2 NLi concentration of 3.4 mol / L. In the electrolytic solution E12, 2.5 molecules of dimethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
  • Electrolytic solution E13 Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E13 having a (FSO 2 ) 2 NLi concentration of 2.9 mol / L. In the electrolytic solution E13, three molecules of dimethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E14 Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E14 having a concentration of (FSO 2 ) 2 NLi of 2.6 mol / L. In the electrolytic solution E14, 3.5 molecules of dimethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
  • Electrolytic solution E15 Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E15 having a (FSO 2 ) 2 NLi concentration of 2.0 mol / L. In the electrolytic solution E15, five molecules of dimethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E16 About 5 mL of ethyl methyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in ethyl methyl carbonate in the flask. When 12.81 g of (FSO 2 ) 2 NLi was added in total, the mixture was stirred overnight. The obtained electrolytic solution was transferred to a 20 mL volumetric flask, and ethyl methyl carbonate was added until the volume became 20 mL. This was designated as an electrolytic solution E16. The production was performed in a glove box under an inert gas atmosphere.
  • the concentration of (FSO 2 ) 2 NLi in the electrolytic solution E16 was 3.4 mol / L.
  • two molecules of ethyl methyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E17 The electrolyte solution E16 was diluted by adding ethyl methyl carbonate to obtain an electrolyte solution E17 having a (FSO 2 ) 2 NLi concentration of 2.9 mol / L. In the electrolytic solution E17, 2.5 molecules of ethyl methyl carbonate are contained per 1 molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E18 The electrolyte solution E16 was diluted by adding ethyl methyl carbonate to obtain an electrolyte solution E18 having a concentration of (FSO 2 ) 2 NLi of 2.2 mol / L. In the electrolytic solution E18, 3.5 molecules of ethyl methyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
  • Electrolytic solution E19 About 5 mL of diethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stirring bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in diethyl carbonate in the flask. When 11.37 g of the total amount of (FSO 2 ) 2 NLi was added, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and diethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution E19. The production was performed in a glove box under an inert gas atmosphere.
  • the concentration of (FSO 2 ) 2 NLi in the electrolytic solution E19 was 3.0 mol / L.
  • two molecules of diethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution E20 Diethyl carbonate was added to the electrolytic solution E19 for dilution to obtain an electrolytic solution E20 having a (FSO 2 ) 2 NLi concentration of 2.6 mol / L. In the electrolytic solution E20, 2.5 molecules of diethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
  • Electrolytic solution E21 Diethyl carbonate was added to the electrolytic solution E19 for dilution to obtain an electrolytic solution E21 having a (FSO 2 ) 2 NLi concentration of 2.0 mol / L. In the electrolytic solution E21, 3.5 molecules of diethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
  • Electrolytic solution C1 (Electrolytic solution C1) Using (CF 3 SO 2) 2 NLi of 5.74 g, as except for using 1,2-dimethoxyethane organic solvents, in the same manner as the electrolyte solution E3, is (CF 3 SO 2) concentration of 2 NLi Electrolyte C1 which is 1.0 mol / L was manufactured. In the electrolytic solution C1, 8.3 molecules of 1,2-dimethoxyethane are contained with respect to (CF 3 SO 2 ) 2 NLi1 molecules.
  • Electrolytic solution C2 (Electrolytic solution C2) Using 5.74 g of (CF 3 SO 2 ) 2 NLi, an electrolytic solution C2 having a concentration of (CF 3 SO 2 ) 2 NLi of 1.0 mol / L was produced in the same manner as the electrolytic solution E3. In the electrolytic solution C2, 16 molecules of acetonitrile are contained with respect to (CF 3 SO 2 ) 2 NLi1 molecule.
  • Electrolytic solution C3 Using 3.74 g of (FSO 2 ) 2 NLi, an electrolytic solution C3 having a concentration of (FSO 2 ) 2 NLi of 1.0 mol / L was produced in the same manner as the electrolytic solution E5. In the electrolytic solution C3, 8.8 molecules of 1,2-dimethoxyethane are contained per molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution C4 Using 3.74 g of (FSO 2 ) 2 NLi, an electrolytic solution C4 having a concentration of (FSO 2 ) 2 NLi of 1.0 mol / L was produced in the same manner as the electrolytic solution E7. In the electrolyte solution C4, 17 molecules of acetonitrile are contained with respect to (FSO 2 ) 2 NLi1 molecule.
  • Electrolytic solution C5 (Electrolytic solution C5) Except that a mixed solvent of ethylene carbonate and diethyl carbonate (volume ratio 3: 7, hereinafter referred to as “EC / DEC”) is used as the organic solvent, and 3.04 g of LiPF 6 is used as the lithium salt.
  • Electrolytic solution C6 Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution C6 having a (FSO 2 ) 2 NLi concentration of 1.1 mol / L. In the electrolytic solution C6, 10 molecules of dimethyl carbonate are contained per 1 molecule of (FSO 2 ) 2 NLi.
  • Electrolytic solution C7 The electrolyte solution E16 was diluted by adding ethyl methyl carbonate to obtain an electrolyte solution C7 having a (FSO 2 ) 2 NLi concentration of 1.1 mol / L.
  • electrolytic solution C7 8 molecules of ethyl methyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecule.
  • Electrolytic solution C8 Diethyl carbonate was added to the electrolytic solution E19 for dilution to obtain an electrolytic solution C8 having a (FSO 2 ) 2 NLi concentration of 1.1 mol / L. In the electrolytic solution C8, 7 molecules of diethyl carbonate are contained per 1 molecule of (FSO 2 ) 2 NLi.
  • Table 4 shows a list of the electrolytic solutions E1 to E21 and the electrolytic solutions C1 to C8.
  • Electrolytic solution E3, electrolytic solution E4, electrolytic solution E7, electrolytic solution E8, electrolytic solution E10, electrolytic solution C2, electrolytic solution C4, and acetonitrile, (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi are as follows: The IR measurement was performed under the following conditions. IR spectra in the range of 2100 cm ⁇ 1 to 2400 cm ⁇ 1 are shown in FIGS. 1 to 10, respectively. Further, IR measurement was performed on the electrolytic solutions E11 to E15, C6, dimethyl carbonate, E16-E18, C7, ethyl methyl carbonate, E19-E21, C8, and diethyl carbonate under the following conditions.
  • FIGS. 11 to 27 show IR spectra in the range of 1900 to 1600 cm ⁇ 1 in FIGS. 11 to 27, respectively.
  • FIG. 28 shows an IR spectrum in the range of 1900 to 1600 cm ⁇ 1 for (FSO 2 ) 2 NLi.
  • the horizontal axis in the figure is the wave number (cm ⁇ 1 ), and the vertical axis is the absorbance (reflection absorbance).
  • IR measurement conditions Device FT-IR (Bruker Optics) Measurement conditions: ATR method (using diamond) Measurement atmosphere: Inert gas atmosphere
  • FIG. IR spectrum of the electrolyte E10 represented by 5 is not a peak derived from acetonitrile observed around 2250 cm -1, inter 2250 cm from the vicinity -1 shifted acetonitrile 2280cm around -1 to the high frequency side C and N
  • the relationship between the peak intensities of Is and Io was Is> Io.
  • Ionic conductivity measurement conditions In an Ar atmosphere, an electrolytic solution was sealed in a glass cell with a platinum constant and a known cell constant, and impedance at 30 ° C. and 1 kHz was measured. The ion conductivity was calculated from the impedance measurement result.
  • Solartron 147055BEC Solartron
  • Electrolytic solution E1, electrolytic solution E2, electrolytic solutions E4 to E6, electrolytic solution E8, electrolytic solution E9, electrolytic solution E11, electrolytic solution E13, electrolytic solution E16, and electrolytic solution E19 all exhibited ion conductivity. Therefore, it can be understood that the electrolytic solution of the present invention can function as an electrolytic solution for various batteries.
  • Electrolytic solution E1 electrolytic solution E2, electrolytic solutions E4 to E6, electrolytic solution E8, electrolytic solution E9, electrolytic solution E11, electrolytic solution E13, electrolytic solution E16, electrolytic solution E19 and electrolytic solutions C1 to C4 and electrolytic solutions C6 to C8
  • the viscosity was measured under the following conditions. The results are shown in Table 6.
  • Viscosity measurement conditions Using a falling ball viscometer (Lovis 2000 M manufactured by Anton Paar GmbH (Anton Paar)), an electrolytic solution was sealed in a test cell under an Ar atmosphere, and the viscosity was measured at 30 ° C.
  • Electrolytic Solution E1 Electrolytic Solution E2, Electrolytic Solutions E4 to E6, Electrolytic Solution E8, Electrolytic Solution E9, Electrolytic Solution E11, Electrolytic Solution E13, Electrolytic Solution E16, and Electrolytic Solution E19 have Viscosities of Electrolytic Solutions C1 to C4 and Electrolytic Solution C6 It was significantly higher than the viscosity of ⁇ C8. Therefore, if the battery uses the electrolytic solution of the present invention, leakage of the electrolytic solution is suppressed even if the battery is damaged.
  • the maximum volatilization rates of the electrolytic solutions E2, E4, E8, E11, and E13 were significantly smaller than the maximum volatilization rates of the electrolytic solutions C1, C2, C4, and C6. Therefore, even if the battery using the electrolytic solution of the present invention is damaged, the volatilization rate of the electrolytic solution is small, so that rapid volatilization of the organic solvent to the outside of the battery is suppressed.
  • Electrolyte E4 did not ignite even after 15 seconds of indirect flame. On the other hand, the electrolytic solution C2 burned out in about 5 seconds.
  • the Li transport number of the electrolytic solutions E2 and E8 was significantly higher than the Li transport number of the electrolytic solutions C4 and C5.
  • the Li ion conductivity of the electrolytic solution can be calculated by multiplying the ionic conductivity (total ionic conductivity) contained in the electrolytic solution by the Li transport number. If it does so, it can be said that the electrolyte solution of this invention has the high transport rate of lithium ion (cation) compared with the conventional electrolyte solution which shows comparable ionic conductivity.
  • Electrolytic solution E11, electrolytic solution E13, electrolytic solution E16, and electrolytic solution E19 were each put in a container, filled with an inert gas, and sealed. These were stored in a freezer at ⁇ 30 ° C. for 2 days. Each electrolyte was observed after storage. None of the electrolytes were solidified and maintained in a liquid state, and no salt deposition was observed.
  • FIGS. 29 to 35 show Raman spectra in which peaks derived from the anion portion of the metal salt of each electrolytic solution were observed.
  • the horizontal axis represents the wave number (cm ⁇ 1 )
  • the vertical axis represents the scattering intensity.
  • FIGS. 29 to 35 it can be seen from FIGS. 29 to 35 that the peak shifts to the higher wavenumber side as the LiFSA concentration increases.
  • (FSO 2 ) 2 N corresponding to the anion of the salt interacts with more Li as the electrolyte concentration increases. It can be considered that such a state was observed as a peak shift of the Raman spectrum.
  • a characteristic peak derived from (FSO 2 ) 2 N of LiFSA dissolved in dimethyl carbonate is observed in 700 to 800 cm ⁇ 1 of the Raman spectra of the electrolytic solutions E11, E13, E15, and C6 shown in FIGS. Observed.
  • the peak shifts to the higher wavenumber side as the concentration of LiFSA increases. This phenomenon is similar to that discussed in the previous paragraph.
  • concentration of the electrolyte is increased, the state in which (FSO 2 ) 2 N corresponding to the anion of the salt interacts with a plurality of Li is shown in the spectrum.
  • Li and anions mainly form SSIP (Solvent-separeted ion pairs) state, and CIP (contact ion pairs) state and AGG ( It is presumed that the aggregate) state is mainly formed. It can be considered that such a change in the state was observed as a peak shift of the Raman spectrum.
  • Example A-1 The lithium ion secondary battery of Example A-1 has a positive electrode, a negative electrode, an electrolytic solution, and a separator.
  • the positive electrode includes a positive electrode active material layer and a current collector covered with the positive electrode active material layer.
  • the positive electrode active material layer has a positive electrode active material, a binder, and a conductive additive.
  • the positive electrode active material is composed of a lithium-containing metal oxide having a layered rock salt structure represented by LiNi 0.5 Co 0.2 Mn 0.3 O 2 .
  • the binder is made of polyvinylidene fluoride (PVDF).
  • the conductive auxiliary agent is made of acetylene black (AB).
  • the current collector is made of an aluminum foil having a thickness of 20 ⁇ m.
  • LiNi 0.5 Co 0.2 Mn 0.3 O 2 , PVDF and AB are mixed so as to have the above mass ratio, and N-methyl-2-pyrrolidone (NMP) as a solvent is mixed.
  • NMP N-methyl-2-pyrrolidone
  • the paste-like positive electrode material was applied to the surface of the current collector using a doctor blade to form a positive electrode active material layer.
  • the positive electrode active material layer was dried at 80 ° C. for 20 minutes to remove NMP by volatilization.
  • the aluminum foil having the positive electrode active material layer formed on the surface thereof was compressed using a roll press, and the aluminum foil and the positive electrode active material layer were firmly bonded.
  • the joined product was heated in a vacuum dryer at 120 ° C.
  • a lithium-containing metal oxide having a layered rock salt structure represented by LiNi 5/10 Co 2/10 Mn 3/10 O 2 is abbreviated as NCM523, acetylene black is abbreviated as AB, and polyvinylidene fluoride is abbreviated.
  • PVdF polyvinylidene fluoride
  • the negative electrode is composed of a negative electrode active material layer and a current collector coated with the negative electrode active material layer.
  • the negative electrode active material layer has a negative electrode active material and a binder.
  • SBR styrene-butadiene rubber
  • CMC carboxymethyl cellulose
  • the slurry-like negative electrode material was applied to a copper foil having a thickness of 20 ⁇ m, which is a negative electrode current collector, in a film shape using a doctor blade to form a negative electrode active material layer.
  • the current collector on which the negative electrode active material layer was formed was dried and pressed, and the bonded product was heated with a vacuum dryer at 100 ° C. for 6 hours, cut into a predetermined shape, and used as a negative electrode.
  • the above electrolytic solution E8 was used as the electrolytic solution of Example A-1.
  • a laminated lithium ion secondary battery was manufactured using the positive electrode, the negative electrode, and the electrolytic solution. Specifically, a cellulose nonwoven fabric (Toyo Filter Paper Co., Ltd. filter paper (cellulose, thickness 260 ⁇ m)) was sandwiched between the positive electrode and the negative electrode to form an electrode plate group. The electrode plate group was covered with a set of two laminated films, and the three sides were sealed, and then the electrolyte solution was poured into the bag-like laminated film. Thereafter, the remaining one side was sealed to obtain a laminate type lithium ion secondary battery in which the four sides were hermetically sealed and the electrode plate group and the electrolyte were sealed. Note that the positive electrode and the negative electrode have a tab that can be electrically connected to the outside, and a part of the tab extends to the outside of the laminated lithium ion secondary battery.
  • Example A-2 The lithium ion secondary battery of Example A-2 is the same as Example A-1 except that the above-described electrolytic solution E4 is used as the electrolytic solution.
  • Example A-3 The lithium ion secondary battery of Example A-3 is the same as Example A-1 except that the electrolytic solution E1 is used as the electrolytic solution.
  • Example A-4 The lithium ion secondary battery of Example A-4 was manufactured as follows.
  • the positive electrode was produced in the same manner as the positive electrode of the lithium ion secondary battery of Example A-1.
  • a cellulose nonwoven fabric having a thickness of 20 ⁇ m was prepared as a separator.
  • a separator was sandwiched between the positive electrode and the negative electrode to form an electrode plate group.
  • the electrode plate group was covered with a set of two laminated films, and the three sides were sealed.
  • the electrolyte solution E8 used in Example A-1 was poured into the bag-like laminated film. Thereafter, the remaining one side was sealed to obtain a lithium ion secondary battery in which the four sides were hermetically sealed and the electrode plate group and the electrolyte were sealed.
  • This battery was designated as the lithium ion secondary battery of Example A-4.
  • Comparative Example A-1 The lithium ion secondary battery of Comparative Example A-1 is the same as Example A-1 except that the above electrolytic solution C5 was used as the electrolytic solution.
  • Comparative Example A-2 The lithium ion secondary battery of Comparative Example A-2 is the same as Example A-4 except that the electrolytic solution C5 used in Comparative Example A-1 was used.
  • Table 10 shows a list of electrolytic solutions of Examples A-1, A-2, A-3, A-4 and Comparative Examples A-1, A-2.
  • Example A-1 and Comparative Example A-1 were evaluated three times for each of the 2-second output and 5-second output.
  • the evaluation results of the output characteristics are shown in Table 11.
  • Table 11 “2 seconds output” means an output 2 seconds after the start of discharge, and “5 seconds output” means an output 5 seconds after the start of discharge.
  • the output of the battery of Example A-1 at 0 ° C. and SOC 20% was 1.2 to 1.3 times higher than the output of the battery of Comparative Example A-1.
  • Example A-1 and Comparative Example A-1 The output characteristics of the batteries of Example A-1 and Comparative Example A-1 are as follows: charge state (SOC) 20%, 25 ° C., operating voltage range 3V-4 Evaluation was performed under the conditions of 0.2 V and a capacity of 13.5 mAh. The output characteristics of Example A-1 and Comparative Example A-1 were evaluated three times for each of the 2-second output and 5-second output. The evaluation results are shown in Table 11.
  • the output of the battery of Example A-1 at 25 ° C. and SOC 20% was 1.2 to 1.3 times higher than the output of the battery of Comparative Example A-1.
  • Example A-1 can suppress a decrease in output at a low temperature to the same extent as the electrolyte solution of Comparative Example A-1.
  • Example A-1 since most of the organic solvent acetonitrile having the hetero element forms a cluster with the lithium salt LIFSA, the vapor pressure of the organic solvent contained in the electrolyte solution becomes low. As a result, volatilization of the organic solvent from the electrolytic solution can be reduced.
  • Comparative Example A-1 an EC solvent is used. EC is mixed to reduce the viscosity and melting point of the electrolyte.
  • the solvent of Comparative Example A-1 also contains DEC, which is a chain carbonate. The chain carbonate is easy to volatilize, and if there is a gap in the battery or damage occurs, a large amount of organic solvent may be instantaneously released out of the system as a gas.
  • the problem of the electrolytic solution of Comparative Example A-1 can be solved.
  • the ionic liquid has a high viscosity and a low ionic conductivity as compared with a normal electrolytic solution, the input / output characteristics are expected to deteriorate. This tendency is remarkable at a low temperature such as 0 ° C., and the 0 ° C. output / 25 ° C. output is expected to be 0.2 or less.
  • the input characteristics of the lithium ion secondary battery were evaluated.
  • the batteries used in this evaluation were the lithium ion batteries of Example A-1, Example A-4, Comparative Example A-1, and Comparative Example A-2, except that a cellulose nonwoven fabric having a thickness of 20 ⁇ m was used as a separator. It is the same as the secondary battery.
  • the batteries corresponding to Examples A-1 and A-4 and Comparative Examples A-1 and A-2 are, in order, the implementation battery A-1, the implementation battery A-4, the comparison battery A-1, and the comparison battery A-2. did.
  • the evaluation conditions were a state of charge (SOC) of 80%, 0 ° C. or 25 ° C., a working voltage range of 3 V to 4.2 V, and a capacity of 13.5 mAh.
  • SOC state of charge
  • the battery input density of the implementation battery A-1 was significantly higher than the battery input density of the comparative battery A-1.
  • the battery input density of Example Battery A-4 was significantly higher than the battery input density of Comparative Battery A-2.
  • Example Battery A-1 Example Battery A-4, Comparison Battery A-1, and Comparison Battery A-2 were evaluated under the following conditions.
  • the evaluation conditions were a state of charge (SOC) of 20%, 0 ° C. or 25 ° C., a working voltage range of 3 V to 4.2 V, and a capacity of 13.5 mAh.
  • SOC 20%, 0 ° C. is a region where output characteristics are difficult to be obtained, for example, when used in a refrigerator room.
  • the output characteristics were evaluated three times for each battery for the 2-second output and 5-second output.
  • the output of the implementation battery A-1 was remarkably higher than the output of the comparison battery A-1 regardless of the difference in temperature.
  • the output of Example Battery A-4 was significantly higher than the output of Comparative Battery A-2.
  • the battery output density of the implementation battery A-1 was significantly higher than the battery output density of the comparative battery A-1.
  • the battery output density of Example Battery A-4 was significantly higher than that of Comparative Battery A-2.
  • thermophysical property test of the positive electrode and the electrolyte in the batteries of Example A-1, Example A-2, and Comparative Example A-1 was performed.
  • Example A-1 did not generate heat near 300 ° C., but Comparative Example A-1 generated heat near 300 ° C. In the battery of Example A-1, it was found that the reactivity between the electrolyte during charging and the positive electrode active material was low, and the thermophysical properties were excellent.
  • Example A-1 since most of the organic solvent acetonitrile having a hetero element forms a cluster with the lithium salt LIFSA, the vapor pressure of the organic solvent contained in the electrolytic solution is lowered. As a result, volatilization of the organic solvent from the electrolytic solution can be reduced. In addition, since the amount of solvent is smaller than usual, the amount of potential heat when burned is small. Furthermore, since the electrolyte solution itself has poor reactivity with oxygen released from the positive electrode, it is considered that the thermophysical property is excellent.
  • the heat generation in the vicinity of 300 ° C. in Comparative Example A-1 is considered to be a reaction between the electrolytic solution and the positive electrode, particularly a reaction between oxygen generated from the positive electrode and the electrolytic solution.
  • the electrolyte solution of Example A-2 generated a very small amount of heat as compared with the electrolyte solution of Comparative Example A-1.
  • the electrolyte solution of Example A-2 since LiTFSA Li ions and solvent molecules attract each other by mutual electrostatic attraction, free solvent molecules do not exist and are difficult to volatilize. In addition, it hardly reacts with the positive electrode active material during charging. For this reason, the battery of Example A-2 is considered to have excellent thermophysical properties.
  • Example A-11 Evaluation of rate capacity characteristics
  • the rate capacity characteristics of Example A-1 and Comparative Example A-1 were evaluated.
  • the capacity of each battery was adjusted to 160 mAh / g.
  • As evaluation conditions after charging at a rate of 0.1 C, 0.2 C, 0.5 C, 1 C, and 2 C, discharging was performed, and the capacity (discharge capacity) of the positive electrode at each rate was measured.
  • 1C indicates a current value required to fully charge or discharge the battery in one hour at a constant current.
  • Table 13 shows the discharge capacity after 0.1 C discharge and after 1 C discharge.
  • the discharge capacity shown in Table 13 is a calculated value of capacity per positive electrode weight.
  • Example A-1 As shown in Table 13, the 0.1 C discharge capacity was not significantly different between Example A-1 and Comparative Example A-1, but the 1 C discharge capacity was greater in Example A-1 than in Comparative Example A-1. Was also big.
  • Example A-5 The electrolyte solution E11 was used as the electrolyte solution of the lithium ion secondary battery of Example A-5.
  • the positive electrode, negative electrode, and separator of the lithium ion secondary battery of Example A-5 were the same as those of Example Battery A-1 (separator thickness 20 ⁇ m).
  • Comparative Example A-3 The positive electrode, negative electrode, separator and electrolyte of the lithium ion secondary battery of Comparative Example A-3 are the same as those of Comparative Battery A-1.
  • the lithium secondary battery of Example A-5 has low resistance even after cycling. Further, it can be said that the lithium secondary battery of Example A-5 has a high capacity retention rate and is hardly deteriorated.
  • Example A-5 As shown in Table 16, the negative electrode of Example A-5 was compared with the negative electrode of Comparative Example A-3 in terms of Ni, Mn, and Co (mass%) and Ni, Mn, and Co ( ⁇ g / sheet). It was low. Combining the results shown in Table 16 with the results shown in Table 15, Example A-5 had less metal elution from the positive electrode than Comparative Example A-3, and the metal eluted from the positive electrode was deposited on the negative electrode. It was found that there was little capacity maintenance rate.
  • Example A-6 and Comparative Example A-4 which are the evaluation targets of Evaluation Example A-14, differ in the basis weight of the battery of Example A-1 and Comparative Example A-1, respectively.
  • the basis weight of the positive electrode was 5.5 mg / cm 2 and the basis weight of the negative electrode was 4 mg / cm 2 .
  • the basis weight of this electrode is half the basis weight of the battery electrode used in the evaluation of the input characteristics and output characteristics (1) to (5) in Evaluation Example A-18, that is, half the battery capacity.
  • the input / output characteristics of each battery were measured under the following three conditions. Table 17 shows the measurement results.
  • Battery A-1 The lithium ion secondary battery of Battery A-1 has the same configuration as the lithium ion secondary battery of Example A-1.
  • the electrolytic solution used in battery A-1 is electrolytic solution E8.
  • the positive electrode is composed of 90 parts by mass of LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM253) as a positive electrode active material, 8 parts by mass of acetylene black (AB) as a conductive auxiliary agent, and a binder. It consists of a positive electrode active material layer composed of 2 parts by mass of certain polyvinylidene fluoride (PVdF) and an aluminum foil (JIS A1000 series) having a thickness of 20 ⁇ m composed of a positive electrode current collector.
  • PVdF polyvinylidene fluoride
  • JIS A1000 series aluminum foil having a thickness of 20 ⁇ m composed of a positive electrode current collector.
  • the negative electrode used in Battery A-1 has a negative electrode active material layer composed of 98 parts by mass of natural graphite as a negative electrode active material, 1 part by mass of SBR and 1 part by mass of CMC as a binder, and a negative electrode current collector having a thickness of 20 ⁇ m. It consists of copper foil.
  • the separator used in Battery A-1 is a cellulose nonwoven fabric having a thickness of 20 ⁇ m.
  • the lithium ion secondary battery of the battery A-2 uses the electrolytic solution E11.
  • the lithium ion secondary battery of battery A-2 is the same as the lithium of battery A-1 except for the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as an ion secondary battery.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • the lithium ion secondary battery of the battery A-3 uses the electrolytic solution E13.
  • the lithium ion secondary battery of battery A-3 is the same as the lithium of battery A-1 except for the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as an ion secondary battery.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • the lithium ion secondary battery of Battery A-C1 uses an electrolytic solution C5.
  • the battery A-C1 lithium ion secondary battery is a battery other than the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery A-1.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • CC charge / discharge that is, constant current charge / discharge
  • the AC impedance after the first charge / discharge and the AC impedance after 100 cycles were measured.
  • the reaction resistances of the electrolytic solution, the negative electrode, and the positive electrode were each analyzed.
  • two circular arcs were seen in the complex impedance plane plot. The arc on the left side of the figure (that is, the side where the real part of the complex impedance is small) is called the first arc.
  • the arc on the right side in the figure is called the second arc.
  • the reaction resistance of the negative electrode was analyzed based on the size of the first arc
  • the reaction resistance of the positive electrode was analyzed based on the size of the second arc.
  • the resistance of the electrolytic solution was analyzed based on the leftmost plot in FIG. 39 continuous with the first arc.
  • Table 18 shows the resistance (so-called solution resistance) of the electrolytic solution after the first charge / discharge, the reaction resistance of the negative electrode, the reaction resistance of the positive electrode, and the diffusion resistance.
  • Table 19 shows the resistance after 100 cycles.
  • the negative electrode reaction resistance and the positive electrode reaction resistance after 100 cycles elapse tend to be lower than the respective resistances after the first charge / discharge.
  • the negative electrode reaction resistance and the positive electrode reaction resistance of the lithium ion secondary batteries of the batteries A-1 to A-3 were the negative electrode reaction of the lithium ion secondary battery of the battery A-C1. Low compared to resistance and positive electrode reaction resistance.
  • the lithium ion secondary batteries of the battery A-1 and the battery A-2 are those using the electrolytic solution of the present invention, and the surfaces of the negative electrode and the positive electrode are S, derived from the electrolytic solution of the present invention. An O-containing film is formed.
  • the S, O-containing film is not formed on the surfaces of the negative electrode and the positive electrode.
  • the negative electrode reaction resistance and the positive electrode reaction resistance of the batteries A-1 and A-2 are lower than those of the lithium ion secondary battery of the battery A-C1. From this, it is presumed that in the batteries A-1 to A-3, the negative electrode reaction resistance and the positive electrode reaction resistance were reduced due to the presence of the S, O-containing film derived from the electrolytic solution of the present invention.
  • the solution resistance of the electrolyte solution in the lithium ion secondary batteries of the battery A-2 and the battery A-C1 is substantially the same, and the solution resistance of the electrolyte solution in the lithium ion secondary battery of the battery A-1 is 2 and higher than batteries A-C1.
  • the solution resistance of each electrolyte solution in each lithium ion secondary battery is the same after the first charge / discharge and after 100 cycles. For this reason, it is considered that each electrolyte solution does not deteriorate in durability, and the difference between the negative electrode reaction resistance and the positive electrode reaction resistance generated in the batteries A-C1 and batteries A-1 to A-3 is the difference between the electrolyte solutions. It is thought that it is not related to durability deterioration but is generated in the electrode itself.
  • the internal resistance of the lithium ion secondary battery can be comprehensively determined from the solution resistance of the electrolytic solution, the reaction resistance of the negative electrode, and the reaction resistance of the positive electrode. Based on the results of Table 18 and Table 19, from the viewpoint of suppressing the increase in internal resistance of the lithium ion secondary battery, the lithium ion secondary battery of battery A-1 has the most excellent durability, and then battery A-2 It can be said that the lithium ion secondary battery is excellent in durability.
  • the lithium ion secondary batteries of the battery A-1 and the battery A-2 do not contain the EC that is the material of the SEI, but the lithium ion secondary battery of the battery A-C1 containing the EC.
  • the capacity retention rate was the same as the battery. This is considered to be because the S and O-containing films derived from the electrolytic solution of the present invention exist on the positive electrode and the negative electrode in the lithium ion secondary batteries of the batteries A-1 and A-2.
  • the lithium ion secondary battery of battery A-2 exhibited a very high capacity retention rate even after 500 cycles had elapsed, and was particularly excellent in durability. From this result, it can be said that when DMC is selected as the organic solvent, the durability is further improved as compared with the case where AN is selected.
  • the working electrode was 0.68 mg.
  • the density of graphite and polyvinylidene fluoride before pressing was 0.68 g / cm 3
  • the density of the active material layer after pressing was 1.025 g / cm 3 .
  • the counter electrode was metal Li.
  • the working electrode, the counter electrode, and the electrolytic solution E8 were accommodated in a battery case with a diameter of 13.82 mm (CR2032 type coin cell case manufactured by Hosen Co., Ltd.) to form a half cell. This was designated as the half cell of Battery A-4.
  • Battery A-5 A half cell of Battery A-5 was produced in the same manner as Battery A-4, except that the electrolytic solution E11 was used.
  • Battery A-6 A half cell of Battery A-6 was produced in the same manner as Battery A-4, except that the electrolytic solution E16 was used.
  • Battery A-7 A half cell of Battery A-7 was produced in the same manner as Battery A-4, except that the electrolytic solution E19 was used.
  • Battery A-C2 A half cell of Battery A-C2 was produced in the same manner as Battery A-4, except that Electrolyte C5 was used.
  • Battery A-4 to Battery A-7 half-cells at 0.2C, 0.5C and 1C rates, and Battery A-4 and Battery A-5 are also compared to Battery A-C1 half-cells at 2C rates. Thus, it was confirmed that the capacity decrease was suppressed and an excellent rate characteristic was exhibited.
  • Each half cell is charged with a 2.0V-0.01V charge / discharge cycle in which CC charging (constant current charging) is performed to 25 ° C. and voltage 2.0V, and CC discharging (constant current discharging) is performed to voltage 0.01V. Perform 3 cycles at a discharge rate of 0.1C, then charge and discharge 3 cycles at each charge / discharge rate in the order of 0.2C, 0.5C, 1C, 2C, 5C, 10C, and finally 3 at 0.1C. Cycle charge / discharge was performed. The capacity retention rate (%) of each half cell was determined by the following formula.
  • Capacity maintenance rate (%) B / A ⁇ 100
  • A Discharge capacity of the second working electrode in the first 0.1 C charge / discharge cycle
  • B Discharge capacity of the second working electrode in the last 0.1 C charge / discharge cycle
  • Table 22 shows the results.
  • the counter electrode is regarded as a negative electrode and the working electrode is regarded as a positive electrode.
  • the lithium ion secondary battery of the battery A-8 using the electrolytic solution E8 is the same as the lithium ion secondary battery of the battery A-1.
  • the electrolyte solution E8 in the lithium ion secondary battery of the battery A-8 has a (FSO 2 ) 2 NLi concentration of 4.5 mol / L.
  • the lithium ion secondary battery of Battery A-9 is the same as the lithium ion secondary battery of Battery A-8, except that electrolytic solution E4 was used as the electrolytic solution.
  • the electrolyte in the lithium ion secondary battery of Battery A-9 is obtained by dissolving (SO 2 CF 3 ) 2 NLi (LiTFSA) as a supporting salt in acetonitrile as a solvent.
  • the concentration of the lithium salt contained in 1 liter of the electrolytic solution is 4.2 mol / L.
  • the electrolytic solution contains two molecules of acetonitrile with respect to one molecule of the lithium salt.
  • the lithium ion secondary battery of the battery A-10 is the same as the lithium ion secondary battery of the battery A-8 except that the electrolytic solution E11 is used as the electrolytic solution.
  • the electrolyte in the lithium ion secondary battery of Battery A-10 is obtained by dissolving LiFSA as a supporting salt in DMC as a solvent.
  • the concentration of the lithium salt contained in 1 liter of the electrolytic solution is 3.9 mol / L.
  • the electrolytic solution contains two molecules of DMC with respect to one molecule of the lithium salt.
  • the lithium ion secondary battery of Battery A-11 uses the electrolytic solution E11.
  • the lithium ion secondary battery of battery A-11 is a battery other than the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery of A-8.
  • NCM523 was used as the positive electrode active material
  • AB was used as the conductive additive for the positive electrode
  • PVdF was used as the binder. This is the same as battery A-8.
  • the basis weight of the active material layer in the positive electrode was 5.5 mg / cm 2 and the density was 2.5 g / cm 3 . The same applies to the following batteries A-12 to A-15 and batteries A-C3 to A-C5.
  • a cellulose nonwoven fabric having a thickness of 20 ⁇ m was used as the separator.
  • the electrolyte in the lithium ion secondary battery of battery A-11 is obtained by dissolving LiFSA as a supporting salt in DMC as a solvent.
  • the concentration of the lithium salt contained in 1 liter of the electrolytic solution is 3.9 mol / L.
  • the electrolytic solution contains two molecules of DMC with respect to one molecule of the lithium salt.
  • the lithium ion secondary battery of Battery A-12 uses the electrolytic solution E8.
  • the lithium ion secondary battery of battery A-12 is composed of the lithium active battery of battery A-8 except for the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as an ion secondary battery.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • the lithium ion secondary battery of the battery A-13 uses the electrolytic solution E11.
  • the lithium ion secondary battery of Battery A-13 includes the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive, and the binder, the type of binder for the negative electrode, the negative electrode active material and the binder, Except for the mixing ratio and the separator, the lithium ion secondary battery of Battery A-8 was the same.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • the lithium ion secondary battery of Battery A-14 uses the electrolytic solution E8.
  • the lithium ion secondary battery of Battery A-14 has a mixing ratio of the positive electrode active material, the conductive additive and the binder, the type of binder for the negative electrode, the mixing ratio of the negative electrode active material and the binder, and Except for the separator, it is the same as the lithium ion secondary battery of Battery A-8.
  • About the positive electrode, it was set as NCM523: AB: PVdF 90: 8: 2.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • the lithium ion secondary battery of Battery A-15 uses the electrolytic solution E13.
  • the lithium ion secondary battery of Battery A-15 is a battery other than the mixing ratio of the positive electrode active material and the conductive additive, the type of binder for the negative electrode, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery A-1.
  • About the positive electrode, it was set as NCM523: AB: PVdF 90: 8: 2.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • Battery A-C3 The lithium ion secondary battery of Battery A-C3 is the same as Battery A-1, except that electrolyte C5 is used.
  • Battery A-C4 The lithium ion secondary battery of batteries A to C4 uses the electrolytic solution C5.
  • Battery A-C4 lithium ion secondary battery is a battery other than the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery A-1.
  • a cellulose nonwoven fabric with a thickness of 20 ⁇ m was used as the separator.
  • the lithium ion secondary battery of batteries A to C5 uses an electrolytic solution C5.
  • Lithium ion secondary batteries of batteries A to C5 include the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive, and the binder, the type of binder for the negative electrode, the negative electrode active material and the binder, Except for the mixing ratio and the separator, the lithium-ion secondary battery of Battery A-1 is the same.
  • the film formed on the surface of the positive electrode in each of the lithium ion secondary batteries of the batteries A-8 to A-15 is replaced with the positive electrode S, O-containing film of the batteries A-8 to A-15.
  • the film formed on the surface of the positive electrode in the lithium ion secondary battery of each of the batteries AC3 to AC5 is abbreviated as the positive electrode film of each of the batteries AC3 to AC5.
  • FIG. 44 shows the analysis results for the elemental sulfur.
  • the electrolyte in the lithium ion secondary battery of Battery A-8 and the electrolyte in the lithium ion secondary battery of Battery A-9 contain sulfur element (S), oxygen element and nitrogen element (N) in the salt.
  • the electrolyte in the lithium ion secondary battery of batteries A to C3 does not contain these in the salt.
  • the electrolytes in the lithium ion secondary batteries of Battery A-8, Battery A-9, and Battery A-C3 all contain fluorine element (F), carbon element (C), and oxygen element (O) in the salt. .
  • the negative electrode S, O-containing film of battery A-8 and the negative electrode S, O-containing film of battery A-9 were analyzed. As a result, a peak indicating the presence of S (FIG. 44) and N A peak indicating the presence of (FIG. 42) was observed. That is, the negative electrode S, O-containing film of Battery A-8 and the negative electrode S, O-containing film of Battery A-9 contained S and N. However, these peaks were not confirmed in the analysis results of the negative electrode film of Battery A-C3. That is, the negative electrode film of Battery A-C3 did not contain an amount exceeding the detection limit for both S and N.
  • each of the negative electrode S, O-containing film and the negative electrode film contains a component derived from the chemical structure of the anion of the metal salt (that is, the supporting salt).
  • FIG. 44 The analysis results of elemental sulfur (S) shown in FIG. 44 were analyzed in more detail.
  • peak separation was performed using a Gauss / Lorentz mixed function.
  • FIG. 45 shows the analysis result of the battery A-8
  • FIG. 46 shows the analysis result of the battery A-9.
  • the negative electrode film of the battery A-C3 did not contain S exceeding the detection limit, but the negative electrode S, O-containing film of the battery A-8 and the negative electrode S, O-containing film of the battery A-9 S was detected. Further, the negative electrode S, O-containing film of Battery A-8 contained more S than the negative electrode S, O-containing film of Battery A-9. Since S was not detected from the negative electrode S, O-containing film of the battery A-C3, S contained in the negative electrode S, O-containing film of each battery was an inevitable impurity or other additive contained in the positive electrode active material. It can be said that it is derived from the metal salt in the electrolytic solution, not derived from.
  • the S element ratio in the negative electrode S, O-containing film of Battery A-8 is 10.4 atomic%
  • the S element ratio in the negative electrode S, O-containing film of Battery A-9 is 3.7 atomic%.
  • the S element ratio in the negative electrode S, O-containing coating is 2.0 atomic% or more, preferably 2.5 atomic% or more, more preferably 3.0. It is at least atomic percent, more preferably at least 3.5 atomic percent.
  • the elemental ratio (atomic%) of S indicates the peak intensity ratio of S when the sum of the peak intensities of S, N, F, C, and O is 100% as described above.
  • the upper limit value of the element ratio of S is not particularly defined, but to be strong, it should be 25 atomic% or less.
  • FIG. 47 is a BF (Bright-field) -STEM image
  • FIGS. 48 to 50 are element distribution images by the SETM-EDX in the same observation region as FIG.
  • FIG. 48 shows the analysis result for C
  • FIG. 49 shows the analysis result for O
  • FIG. 50 shows the analysis result for S. 48 to 50 show the analysis results of the negative electrode in the discharged lithium ion secondary battery.
  • a black portion exists in the upper left part of the STEM image. This black part is derived from Pt deposited in the pretreatment of FIB processing.
  • a portion above the Pt-derived portion (referred to as a Pt portion) can be regarded as a contaminated portion after Pt deposition. Therefore, in FIGS. 48 to 50, only the portion below the Pt portion was examined.
  • C was layered below the Pt portion. This is considered to be a layered structure of graphite as a negative electrode active material.
  • O exists in the part corresponding to the outer periphery and interlayer of graphite.
  • S exists in the part corresponding to the outer periphery and interlayer of graphite. From these results, it is surmised that the negative electrode S, O-containing film containing S and O, such as the S ⁇ O structure, is formed between the surface and the interlayer of graphite.
  • the thickness of the negative electrode S, O-containing film increases after charging. From this result, it is presumed that the negative electrode S, O-containing film has a fixing portion that stably exists with respect to charging and discharging and an adsorption portion that increases and decreases with charging and discharging. And it is estimated that the thickness of the negative electrode S, O-containing film increased or decreased during charging / discharging due to the presence of the adsorbing portion.
  • the positive electrode S, O-containing film of the battery A-8 also contains S and O.
  • the height of the peak existing in the vicinity of 529 eV decreases after the cycle.
  • This peak is considered to indicate the presence of O derived from the positive electrode active material.
  • photoelectrons excited by O atoms in the positive electrode active material pass through the S, O-containing coating and are detected. It is thought that it was done. Since this peak decreased after the cycle, it is considered that the thickness of the S, O-containing film formed on the positive electrode surface increased with the cycle.
  • O and S in the positive electrode S, O-containing film increased during discharging and decreased during charging. From this result, it is considered that O and S enter and leave the positive electrode S and O-containing film with charge and discharge. From this fact, the concentration of S and O in the positive electrode S and O-containing coating is increased or decreased during charging or discharging, or the presence of an adsorbing portion in the positive electrode S and O-containing coating as well as the negative electrode S and O-containing coating. It is estimated that the thickness increases or decreases.
  • the positive electrode S, O-containing film and the negative electrode S, O-containing film were also subjected to XPS analysis for the lithium ion secondary battery of the battery A-11.
  • the lithium ion secondary battery of battery A-11 was set to 25 ° C., operating voltage range 3.0V to 4.1V, and CC charge / discharge was repeated 500 cycles at a rate of 1C. After 500 cycles, the XPS spectrum of the positive electrode S, O-containing film was measured in a discharge state of 3.0 V and a charge state of 4.0 V. Further, the negative electrode S, O-containing coating in the 3.0V discharge state before the cycle test (that is, after the first charge / discharge) and the negative electrode S, O-containing coating in the 3.0V discharge state after 500 cycles are measured by XPS. Elemental analysis was performed, and the S element ratio contained in the negative electrode S, O-containing film was calculated.
  • FIG. 53 and 54 show the analysis results of the positive electrode S, O-containing film of the battery A-11 measured by XPS. Specifically, FIG. 53 shows the analysis result for sulfur element, and FIG. 54 shows the analysis result for oxygen element.
  • Table 26 shows the S element ratio (atomic%) of the negative electrode film measured by XPS. The S element ratio was calculated in the same manner as the above-mentioned item “S element ratio of negative electrode S, O-containing film”.
  • a peak indicating the presence of S and a peak indicating the presence of O were also detected from the positive electrode S, O-containing film in the lithium ion secondary battery of battery A-11.
  • the negative electrode S, O-containing film of the battery A-11 contained 2.0 atomic% or more of S even after the first charge / discharge and after 500 cycles. From this result, it can be seen that the negative electrode S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention contains 2.0 atomic% or more of S before or after the cycle.
  • the batteries A-11 to A-14, the batteries A-C4, and the batteries A-C5 were subjected to a high-temperature storage test in which they were stored at 60 ° C. for 1 week, and each battery A-
  • the positive electrode S, O-containing film and negative electrode S, O-containing film of 11 to A-14, and the positive electrode film and negative electrode film of each of the batteries A-C4 and A-C5 were analyzed.
  • CC-CV charge was performed at a rate of 0.33 C from 3.0 V to 4.1 V.
  • the charge capacity at this time was set as a standard (SOC100), 20% of the standard was CC discharged and adjusted to SOC80, and then a high-temperature storage test was started.
  • FIGS. 59 to 62 show analysis results of the negative electrode S, O-containing coatings of the batteries A-11 to A-14 and the negative coatings of the batteries A-C4 and A-C5 measured by XPS.
  • FIG. 55 shows the analysis results for the elemental sulfur of the positive electrode S, O-containing film of the battery A-11 and the battery A-12 and the positive electrode film of the battery A-C4.
  • FIG. 56 shows analysis results of elemental sulfur in the positive electrode S, O-containing coatings of batteries A-13 and A-14 and the positive coating of batteries A-C5.
  • FIG. 57 shows the results of analysis of oxygen elements in the positive electrode S, O-containing coatings of batteries A-11 and A-12 and the positive coating of batteries A-C4.
  • FIG. 58 shows the analysis results of oxygen elements in the positive electrode S, O-containing coatings of batteries A-13 and A-14 and the positive coating of batteries A to C5.
  • FIG. 55 shows the analysis results for the elemental sulfur of the positive electrode S, O-containing film of the battery A-11 and the battery A-12 and the positive electrode film of the battery A-C4.
  • FIG. 56 shows analysis results of elemental sulfur in the positive electrode S, O-containing coatings of batteries A-13 and A-14 and the positive coating of batteries A-C5.
  • FIG. 59 shows the results of analysis of sulfur elements in the negative electrode S, O-containing coatings of batteries A-11 and A-12 and the negative coatings of batteries A-C4.
  • FIG. 60 shows the analysis results for the elemental sulfur in the negative electrode S, O-containing coatings of batteries A-13 and A-14 and the negative coating of batteries A-C5.
  • FIG. 61 shows the analysis results of oxygen elements in the negative electrode S, O-containing coatings of batteries A-11 and A-12 and the negative coating of batteries A-C4.
  • FIG. 62 shows the analysis results of oxygen elements in the negative electrode S, O-containing coatings of batteries A-13 and A-14 and the negative coating of batteries A-C5.
  • the lithium ion secondary batteries of batteries A-C4 and batteries A-C5 using the conventional electrolyte solution do not contain S in the positive electrode film
  • the electrolyte solution of the present invention Lithium ion secondary batteries of batteries A-11 to A-14 using the above materials contained S in the positive electrode S, O-containing film.
  • all of the lithium ion secondary batteries of the batteries A-11 to A-14 contained O in the positive electrode S, O-containing coating.
  • the positive electrode S and O-containing films in the lithium ion secondary batteries of the batteries A-11 to A-14 all have SO 2 (S ⁇ O structure).
  • the lithium ion secondary batteries of the batteries A-11 to A-14 also contain S and O in the negative electrode S and O-containing coating, which have an S ⁇ O structure and are electrolyzed. It turns out that it originates in a liquid. And it turns out that this negative electrode S and O containing film
  • the XPS spectrum of each of the negative electrode S and O-containing coatings and the negative electrode coatings after the high-temperature storage test and discharge was measured.
  • the ratio of S element during discharge in the negative electrode S, O-containing film of battery A-12 and the negative electrode film of battery A-C4 was calculated.
  • the element ratio of S was calculated when the sum of the peak intensities of S, N, F, C, and O was 100%. The results are shown in Table 27.
  • the negative electrode film of Battery A-C4 did not contain S exceeding the detection limit, but S was detected from the negative electrode S, O-containing film of Battery A-11 and Battery A-12. It was. Further, the negative electrode S, O-containing film of Battery A-12 contained more S than the negative electrode S, O-containing film of Battery A-11. Further, from this result, it is understood that the S element ratio in the negative electrode S, O-containing film is 2.0 atomic% or more even after high temperature storage.
  • the lithium ion secondary batteries of the battery A-11, the battery A-12, and the battery A-15 did not contain EC that is a material of SEI, but included batteries A-C4 containing EC. Capacity retention rate equivalent to that of the lithium ion secondary battery. This is presumably because the S and O containing film derived from the electrolytic solution of the present invention exists in the positive electrode and the negative electrode in the lithium ion secondary battery of each battery.
  • the lithium ion secondary battery of the battery A-11 showed an extremely high capacity retention rate even after 500 cycles had elapsed, and was particularly excellent in durability. From this result, it can be said that when DMC is selected as the organic solvent, the durability is further improved as compared with the case where AN is selected.
  • the lithium ion secondary batteries of Battery A-11, Battery A-12, and Battery A-C4 were subjected to a high-temperature storage test that was stored at 60 ° C. for 1 week.
  • CC-CV constant current constant voltage
  • the charge capacity at this time was set as a standard (SOC100), 20% of the standard was CC discharged and adjusted to SOC80, and then a high-temperature storage test was started.
  • SOC100 standard
  • CC-CV discharge was performed to 3.0V at 1C. From the ratio of the discharge capacity at this time and the SOC 80 capacity before storage, the remaining capacity was calculated as follows. The results are shown in Table 29.
  • Residual capacity 100 x (CC-CV discharge capacity after storage) / (SOC 80 capacity before storage)
  • the remaining capacity of the nonaqueous electrolyte secondary batteries of the batteries A-11 and A-12 is larger than the remaining capacity of the nonaqueous electrolyte secondary battery of the batteries A to C4. From this result, it can be said that the S, O-containing coating derived from the electrolytic solution of the present invention and formed on the positive electrode and the negative electrode contributes to an increase in the remaining capacity.
  • the surface of the aluminum foil of the lithium ion secondary batteries of Battery A-8 and Battery A-9 after washing was subjected to surface analysis by X-ray photoelectron spectroscopy (XPS) while etching by Ar sputtering.
  • XPS X-ray photoelectron spectroscopy
  • AlF 3 is observed at the Al peak position 76.3 eV
  • pure Al is observed at the Al peak position 73 eV
  • Al peak position is observed.
  • the broken lines shown in FIGS. 63 and 64 show typical peak positions of AlF 3 , Al, and Al 2 O 3, respectively.
  • the surface of the aluminum foil of the lithium ion secondary battery after charging and discharging according to the present invention has an Al—F bond (presumed to be AlF 3 ) layer with a thickness of about 25 nm in the depth direction. It was confirmed that an Al—F bond (presumed to be AlF 3 ) and an Al—O bond (presumed to be Al 2 O 3 ) were formed.
  • the nonaqueous electrolyte secondary battery of battery A-11 was charged and discharged at 25 ° C. for 3 cycles, then disassembled in a 3V discharge state, and the positive electrode was taken out.
  • the nonaqueous electrolyte secondary battery of Battery A-11 was charged and discharged for 500 cycles at 25 ° C., then disassembled in a 3 V discharge state, and the positive electrode was taken out.
  • the non-aqueous electrolyte secondary battery of Battery A-11 was charged and discharged at 25 ° C. for 3 cycles, then left at 60 ° C. for 1 month, disassembled in a 3 V discharge state, and the positive electrode was taken out.
  • Each positive electrode was washed with DMC three times to obtain a positive electrode for analysis.
  • the positive electrode S and O containing film was formed in the said positive electrode, and the structural information of the molecule
  • Each positive electrode for analysis was analyzed by TOF-SIMS.
  • a time-of-flight secondary ion mass spectrometer was used as a mass spectrometer, and positive secondary ions and negative secondary ions were measured.
  • Bi was used as the primary ion source, and the primary acceleration voltage was 25 kV.
  • Ar-GCIB Ar1500 was used as the sputter ion source.
  • Tables 30 to 32 The measurement results are shown in Tables 30 to 32.
  • the positive ion intensity (relative value) of each fragment is a relative value with the total positive ion intensity of all detected fragments as 100%.
  • the negative ionic strength (relative value) of each fragment described in Table 32 is a relative value where the sum of the negative ionic strengths of all detected fragments is 100%.
  • the fragments presumed to be derived from the solvent of the electrolytic solution were only C 3 H 3 and C 4 H 3 detected as positive secondary ions.
  • a fragment presumed to be derived from a salt of the electrolytic solution is mainly detected as a negative secondary ion, and has a higher ionic strength than the above-described fragment derived from a solvent.
  • fragments containing Li are mainly detected as positive secondary ions, and the ionic strength of the fragments containing Li accounts for a large proportion of positive secondary ions and negative secondary ions.
  • the main component of the S, O-containing coating of the present invention is a component derived from the metal salt contained in the electrolytic solution, and that the S, O-containing coating of the present invention contains a large amount of Li. Is done.
  • SNO 2 , SFO 2 , S 2 F 2 NO 4 and the like have also been detected as fragments presumed to be derived from salts.
  • the conventional electrolyte solution introduced in, for example, the above-mentioned JP2013-145732 that is, a conventional electrolyte solution containing EC as an organic solvent, LiPF 6 as a metal salt, and LiFSA as an additive
  • S is taken into the decomposition product of the organic solvent.
  • S is considered to exist as ions such as C p H q S (p and q are independent integers) in the negative electrode film and / or the positive electrode film.
  • the fragment containing S detected from the S, O-containing film of the present invention is not a C p H q S fragment but mainly a fragment reflecting an anion structure. It is. This also reveals that the S, O-containing coating of the present invention is fundamentally different from a coating formed on a conventional nonaqueous electrolyte secondary battery.
  • a half cell using the electrolytic solution E8 was produced as follows.
  • An aluminum foil (JIS A1000 series) having a diameter of 13.82 mm, an area of 1.5 cm 2 and a thickness of 20 ⁇ m was used as a working electrode, and the counter electrode was metal Li.
  • As the separator Whatman glass filter nonwoven fabric having a thickness of 400 ⁇ m: product number 1825-055 was used.
  • a working electrode, a counter electrode, a separator, and an electrolytic solution were housed in a battery case (CR2032-type coin cell case manufactured by Hosen Co., Ltd.) to form a half cell. This was made into the half cell of battery A1.
  • Battery A2 A half cell of the battery A2 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E11 was used.
  • Battery A3 A half cell of the battery A3 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E16 was used.
  • Battery A4 A half cell of the battery A4 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E19 was used.
  • Battery A5 A half cell of the battery A5 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E13 was used.
  • Battery AC1 A half cell of the battery AC1 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution C5 was used.
  • Battery AC2 A half cell of the battery AC2 was produced in the same manner as the half cell of the battery A1, except that the battery C6 was used.
  • Cyclic voltammetry evaluation with working electrode Al Cyclic voltammetry was evaluated for 5 cycles under conditions of 3.1 V to 4.6 V and 1 mV / s on the half cells of the batteries A1 to A4 and the battery AC1, and then 3.1 V to 5.1 V, 1 mV / s. Cyclic voltammetry was evaluated for 5 cycles under the conditions of s. 65 to 73 show graphs showing the relationship between the potential and the response current with respect to the half cells of the batteries A1 to A4 and the battery AC1.
  • FIG. 73 shows that in the half cell of the battery AC1, the current flows from 3.1 V to 4.6 V after the second cycle, and the current increases as the potential increases. Also, from FIGS. 78 and 79, in the half cell of the battery AC2, similarly, the current flows from 3.0 V to 4.5 V after the second cycle, and the current increases as the potential increases. This current is presumed to be the oxidation current of Al due to the corrosion of the working electrode aluminum.
  • each of the electrolytic solutions E8, E11, E16, and E19 can be said to be a preferable electrolytic solution for a battery using aluminum as a current collector.
  • electrolytic solution of the present invention include the following electrolytic solutions.
  • the following electrolytes include those already described.
  • the electrolytic solution of the present invention was produced as follows. About 5 mL of 1,2-dimethoxyethane, which is an organic solvent, was placed in a flask equipped with a stir bar and a thermometer. Under stirring conditions, (CF 3 SO 2 ) 2 NLi, which is a lithium salt, was gradually added to 1,2-dimethoxyethane in the flask so as to keep the solution temperature at 40 ° C. or lower and dissolved. When about 13 g of (CF 3 SO 2 ) 2 NLi was added, the dissolution of (CF 3 SO 2 ) 2 NLi temporarily stagnated. Therefore, the flask was put into a thermostat, and the solution temperature in the flask was 50 ° C.
  • (CF 3 SO 2 ) 2 NLi was dissolved.
  • the dissolution of (CF 3 SO 2 ) 2 NLi stagnated again, so 1 drop of 1,2-dimethoxyethane was added with a pipette (CF 3 SO 2 ) 2 NLi dissolved.
  • (CF 3 SO 2 ) 2 NLi was gradually added, and the entire amount of predetermined (CF 3 SO 2 ) 2 NLi was added.
  • the resulting electrolyte was transferred to a 20 mL volumetric flask and 1,2-dimethoxyethane was added until the volume was 20 mL.
  • the obtained electrolytic solution had a volume of 20 mL, and (CF 3 SO 2 ) 2 NLi contained in this electrolytic solution was 18.38 g. This was designated as an electrolytic solution A.
  • the concentration of (CF 3 SO 2 ) 2 NLi in the electrolytic solution A was 3.2 mol / L, and the density was 1.39 g / cm 3 .
  • the density was measured at 20 ° C. The production was performed in a glove box under an inert gas atmosphere.
  • Electrolytic solution B By a method similar to that for the electrolytic solution A, an electrolytic solution B having a (CF 3 SO 2 ) 2 NLi concentration of 2.8 mol / L and a density of 1.36 g / cm 3 was produced.
  • Electrolytic solution C About 5 mL of acetonitrile, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (CF 3 SO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in acetonitrile in the flask. The mixture was stirred overnight when the prescribed (CF 3 SO 2 ) 2 NLi was added. The resulting electrolyte was transferred to a 20 mL volumetric flask and acetonitrile was added until the volume was 20 mL. This was designated as an electrolytic solution C. The production was performed in a glove box under an inert gas atmosphere.
  • the electrolytic solution C had a (CF 3 SO 2 ) 2 NLi concentration of 4.2 mol / L and a density of 1.52 g / cm 3 .
  • Electrolytic solution D By a method similar to that of the electrolytic solution C, an electrolytic solution D having a concentration of (CF 3 SO 2 ) 2 NLi of 3.0 mol / L and a density of 1.31 g / cm 3 was produced.
  • Electrolytic solution F The concentration of (CF 3 SO 2 ) 2 NLi is 3.2 mol / L and the density is 1.49 g / cm 3 except that dimethyl sulfoxide is used as the organic solvent. Electrolytic solution F was produced.
  • Electrolytic solution J (Electrolytic solution J) Except that acetonitrile was used as the organic solvent, an electrolytic solution J having a concentration of (FSO 2 ) 2 NLi of 5.0 mol / L and a density of 1.40 g / cm 3 in the same manner as the electrolytic solution G Manufactured.
  • Electrolytic solution K In the same manner as the electrolytic solution J, an electrolytic solution K having a concentration of (FSO 2 ) 2 NLi of 4.5 mol / L and a density of 1.34 g / cm 3 was produced.
  • Electrolytic solution L About 5 mL of dimethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to dimethyl carbonate in the flask and dissolved. When (FSO 2 ) 2 NLi was added in a total amount of 14.64 g, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and dimethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution L. The production was performed in a glove box under an inert gas atmosphere. The concentration of (FSO 2 ) 2 NLi in the electrolytic solution L was 3.9 mol / L, and the density of the electrolytic solution L was 1.44 g / cm 3 .
  • Electrolytic solution N About 5 mL of ethyl methyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in ethyl methyl carbonate in the flask. When 12.81 g of (FSO 2 ) 2 NLi was added in total, the mixture was stirred overnight. The obtained electrolytic solution was transferred to a 20 mL volumetric flask, and ethyl methyl carbonate was added until the volume became 20 mL. This was designated as an electrolytic solution N. The production was performed in a glove box under an inert gas atmosphere. The concentration of (FSO 2 ) 2 NLi in the electrolytic solution N was 3.4 mol / L, and the density of the electrolytic solution N was 1.35 g / cm 3 .
  • Electrolytic solution O About 5 mL of diethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stirring bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in diethyl carbonate in the flask. When 11.37 g of the total amount of (FSO 2 ) 2 NLi was added, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and diethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution O. The production was performed in a glove box under an inert gas atmosphere. The concentration of (FSO 2 ) 2 NLi in the electrolytic solution O was 3.0 mol / L, and the density of the electrolytic solution O was 1.29 g / cm 3 .
  • Table 33 shows a list of the above electrolytes.
  • Example B-1 A half cell having a positive electrode (working electrode) and an electrolytic solution was prepared and subjected to cyclic voltammetry (CV) evaluation.
  • the positive electrode includes a positive electrode active material layer and a current collector covered with the positive electrode active material layer.
  • the positive electrode active material layer has a positive electrode active material, a binder, and a conductive additive.
  • the positive electrode active material is made of LiMn 2 O 4 .
  • the binder is made of polyvinylidene fluoride (PVDF).
  • the conductive auxiliary agent is made of acetylene black (AB).
  • the current collector is made of an aluminum foil having a thickness of 20 ⁇ m.
  • LiMn 2 O 4 , PVDF and AB are mixed so as to have the above mass ratio, and N-methyl-2-pyrrolidone (NMP) as a solvent is added to form a paste-like positive electrode material and To do.
  • NMP N-methyl-2-pyrrolidone
  • the paste-like positive electrode material was applied to the surface of the current collector using a doctor blade to form a positive electrode active material layer.
  • the positive electrode active material layer was dried at 80 ° C. for 20 minutes to remove NMP by volatilization.
  • the aluminum foil having the positive electrode active material layer formed on the surface thereof was compressed using a roll press, and the aluminum foil and the positive electrode active material layer were firmly bonded.
  • the joined product was heated in a vacuum dryer at 120 ° C. for 6 hours, cut into a predetermined shape, and a positive electrode was obtained.
  • the above electrolytic solution E8 was used as the electrolytic solution of Example B-1.
  • a half cell was manufactured using the positive electrode (working electrode) and the electrolytic solution.
  • the counter electrode is made of metallic lithium.
  • the separator is made of a glass filter nonwoven fabric.
  • Example B-2 The electrolyte solution E4 described above was used as the electrolyte solution of Example B-2. Other points of the half cell of Example B-2 are the same as those of Example B-1.
  • Example B-3 The electrolyte solution E11 described above was used as the electrolyte solution of Example B-3. Other points of the half cell of Example B-3 are the same as those of Example B-1.
  • Example B-1 CV Evaluation
  • the half cell of Example B-1 was subjected to a cyclic voltammetry (CV) evaluation test.
  • the evaluation conditions were a sweep rate of 0.1 mV / s and a sweep range of 3.1 V to 4.6 V (vs Li), and charging and discharging were repeated for two cycles.
  • the results of CV measurement are shown in FIG.
  • the horizontal axis represents the potential of the working electrode (vs. Li / Li + ), and the vertical axis represents the current generated by redox.
  • FIG. 80 an oxidation peak was observed near 4.4V, and a reduction peak was observed near 3.8V, indicating that a reversible electrochemical reaction occurred. From this, it was found that an electrochemical reaction occurs reversibly in the non-aqueous secondary battery including the positive electrode and the electrolytic solution.
  • Example B-3 had larger charge capacity and discharge capacity than Examples B-1, Example B-2, and Comparative Example B-1. For this reason, the reversible capacity of Example B-3 increased. The reason is not clear, but it is presumed that the usable capacity of the chain carbonate-based high-concentration electrolytic solution is increased by reducing the initial irreversible capacity.
  • Example C-1 is a half cell including a working electrode (positive electrode), a counter electrode (negative electrode), and an electrolytic solution.
  • the positive electrode as the working electrode includes a positive electrode active material layer and a current collector covered with the positive electrode active material layer.
  • the positive electrode active material layer has a positive electrode active material, a binder, and a conductive additive.
  • the positive electrode active material is made of LiFePO 4 having 10% conductive carbon and an olivine structure.
  • the binder is made of polyvinylidene fluoride (PVDF).
  • the conductive auxiliary agent is made of acetylene black (AB).
  • the current collector is made of an aluminum foil having a thickness of 20 ⁇ m.
  • LiFePO 4 , PVDF and AB are mixed so as to have the above mass ratio, and N-methyl-2-pyrrolidone (NMP) as a solvent is added to obtain a paste-like positive electrode material.
  • NMP N-methyl-2-pyrrolidone
  • the paste-like positive electrode material was applied to the surface of the current collector using a doctor blade to form a positive electrode active material layer.
  • the positive electrode active material layer was dried at 80 ° C. for 20 minutes to remove NMP by volatilization.
  • the aluminum foil having the positive electrode active material layer formed on the surface thereof was compressed using a roll press, and the aluminum foil and the positive electrode active material layer were firmly bonded.
  • the joined product was heated in a vacuum dryer at 120 ° C. for 6 hours, cut into a predetermined shape, and a positive electrode was obtained.
  • the above electrolytic solution E8 was used as the electrolytic solution of Example C-1.
  • a half cell was manufactured using the positive electrode (working electrode) and the electrolytic solution.
  • the counter electrode is made of metallic lithium.
  • the separator is made of a glass filter (GE Healthcare Japan, Inc., thickness 400 ⁇ m).
  • Example C-2 The half cell of Example C-2 uses the above-described electrolytic solution E11 as the electrolytic solution.
  • the other configuration is the same as that of Example C-1.
  • Example C-3 The half cell of Example C-3 uses the above-described electrolytic solution E13 as the electrolytic solution.
  • the other configuration is the same as that of Example C-1.
  • Comparative Example C-1 The half cell of Comparative Example C-1 uses the above electrolytic solution C5 as the electrolytic solution.
  • the other configuration is the same as that of Example C-1.
  • Comparative Example C-2 The half cell of Comparative Example C-2 uses the above electrolytic solution C6 as the electrolytic solution.
  • the other configuration is the same as that of Example C-1.
  • Example C-1 Rate Capacity Evaluation 1
  • the half cell of Example C-1 and Comparative Example C-1 has a rate of 0.1 C (1 C represents a current value required to fully charge or discharge the battery in one hour at a constant current).
  • 2V vs Li
  • discharge curves at various rates are shown in FIGS.
  • the ratio (rate capacity characteristics) of the discharge capacity at 5C and 10C with respect to the 0.1C discharge capacity was calculated. The results are shown in Table 34.
  • the half cell of Example C-1 of the present invention has a reduced capacity drop when the rate is increased compared to the half cell of Comparative Example C-1. It showed excellent rate capacity characteristics. It was found that the secondary battery using the electrolytic solution of the present invention exhibits excellent rate capacity characteristics.
  • Example C-3 Rate Capacity Evaluation 2
  • the half cell of Example C-2 was repeatedly charged and discharged with a constant current in the range of 2.5 to 4.0 V.
  • the discharge capacity in each cycle of charge and discharge was measured.
  • the charge and discharge rates were changed every three cycles as follows. 0.1C, 3 cycles ⁇ 0.2C, 3 cycles ⁇ 0.5C, 3 cycles ⁇ 1C, 3 cycles ⁇ 2C, 3 cycles ⁇ 5C, 3 cycles ⁇ 0.1C, 3 cycles Discharge rate capacity for each cycle Measured and shown in FIG.
  • the discharge capacity at the second cycle among the three cycles at 0.1 C and 5 C is shown in Table 35.
  • Examples C-2 and C-3 had higher discharge rate capacities than Comparative Examples C-1 and C-2.
  • the discharge rate capacities at the rates of 0.5 C to 5 C were significantly higher in Examples C-2 and C-3 than in Comparative Examples C-1 and C-2.
  • the rate capacity of Example C-2 was higher than that of Example C-3.
  • Example C-4 Rate Capacity Evaluation at Low Temperature
  • the half cells of Example C-1 and Comparative Example C-1 were subjected to constant current charging at a 0.1 C rate to 4.2 V (vs Li) in an environment of ⁇ 20 ° C., and then 0.05 C, 0
  • the battery was discharged at a rate of 5 C to 2 V, and the discharge capacity and the charge capacity at each rate were measured.
  • the charge / discharge curves at the respective rates of the half cell of Example C-1 are shown in FIG. 86, and the charge / discharge curves at the respective rates of the half cell of Comparative Example C-1 are shown in FIG.
  • Example C-1 has higher rate capacity characteristics (0.5 C / 0.05 C capacity) for both charging and discharging than Comparative Example C-1.
  • FIGS. 86 and 87 when Example C-1 is compared with Comparative Example C-1, in Comparative Example C-1, for example, the charge curve potential (closed circuit potential) and discharge at a point of 50 mAh / g The difference from the curve potential (closed circuit potential) is large, and this difference is particularly noticeable during high-rate tests such as 1 / 2C.
  • Example C-1 the potential difference is extremely small compared to Comparative Example C-1. In other words, it can be said that Example C-1 has a smaller polarization than Comparative Example C-1.
  • the working electrode was platinum (Pt) and the counter electrode was lithium metal (Li).
  • the separator was a glass filter nonwoven fabric. Using the electrolytic solution E1, the working electrode, the electrolytic solution, and the separator, a half cell of the battery D-1 was manufactured.
  • Battery D-2 A half cell of battery D-2 was produced in the same manner as battery D-1, except that electrolyte E4 was used as the electrolyte.
  • Battery D-3 A half cell of Battery D-3 was produced by the following method.
  • the working electrode was created as follows. 89 parts by mass of LiNi 0.5 Mn 1.5 O 4 as an active material and 11 parts by mass of polyvinylidene fluoride as a binder were mixed. This mixture was dispersed in an appropriate amount of N-methyl-2-pyrrolidone to prepare a slurry. A copper foil having a thickness of 20 ⁇ m was prepared as a current collector. The slurry was applied in a film form on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried to remove N-methyl-2-pyrrolidone, and then the copper foil was pressed to obtain a bonded product.
  • the obtained joined product was heat-dried at 120 ° C. for 6 hours with a vacuum dryer to obtain a copper foil on which an active material layer was formed.
  • the mass of the active material per 1 cm 2 of the copper foil was 6.3 mg.
  • the counter electrode was lithium metal.
  • a separator made of a working electrode, a counter electrode, a glass filter nonwoven fabric, and an electrolytic solution E4 were accommodated in a battery case (CR2032 type coin cell case manufactured by Hosen Co., Ltd.) having a diameter of 13.82 mm to form a half cell. This was designated as a half cell of Battery D-3.
  • Battery D-4 A half cell of the battery D-4 was produced in the same manner as the battery D-3 except that the electrolytic solution E11 was used.
  • Battery D-C1 A half cell of Battery D-C1 was produced in the same manner as Battery D-1, except that Electrolytic Solution C1 was used as the electrolytic solution.
  • the battery D-C2 was the same as the battery D-1, except that the electrolyte used was an electrolyte C9 in which the organic solvent was DME and the concentration of (CF 3 SO 2 ) 2 NLi was 0.1 mol / L. Half cell was manufactured.
  • the electrolytic solution C9 of the battery D-C2 contains 93 molecules of 1,2-dimethoxyethane with respect to (CF 3 SO 2 ) 2 NLi1 molecules.
  • Table 38 shows a list of electrolytes used for each battery.
  • FIG. 89 indicates the potential (V) with the Li + / Li electrode as the reference potential, and the vertical axis indicates the current value (mAcm ⁇ 2 ).
  • the horizontal axis in FIG. 89 represents the potential (V) with the Li + / Li electrode as the reference potential, and the vertical axis represents the current value ( ⁇ A).
  • the rising portion of the potential-current curve of the battery D-1 was located on the higher potential side than the rising portions of Comparative Examples 1 and 2.
  • the starting point of the rising portion is located at a potential of 4.7 V when the Li / Li + electrode is used as a reference potential, and the rising portion is indicated by a potential higher than the starting point potential of 4.7 V. It had been.
  • the starting point of the rising portion is located at a potential of 5.7 V when the Li / Li + electrode is used as a reference potential, and the rising portion is indicated by a potential higher than the starting point potential of 5.7 V. It had been. From the above, it was found that the electrolytic solution of the battery D-1 has an oxidative decomposition potential at which an oxidation reaction occurs is 4.5 V or more, and the battery D-2 has 5 V or more.
  • a normal secondary battery includes a detection unit that detects a sudden drop in voltage that occurs during full charge and a termination unit that stops charging when a sudden voltage drop occurs.
  • Lithium ion secondary battery prepared using electrolyte C9 of battery D-C2 is erroneously determined to be a sudden voltage drop seen by overcharging by the detecting means during charging from the start of voltage application to the rising part, and is terminated. The charging may be stopped by the means.
  • the half cell of the battery D-3 was able to charge and discharge reversibly at 4.8V. Further, as shown in FIG. 91, the half cell of the battery D-4 was able to be reversibly charged / discharged at 4.9V. The capacity of the half cell of Battery D-4 was about 120 mAh / g.
  • the working electrode was 0.68 mg.
  • the density of graphite and polyvinylidene fluoride before pressing was 0.68 g / cm 3
  • the density of the active material layer after pressing was 1.025 g / cm 3 .
  • the counter electrode was metal Li.
  • the working electrode, counter electrode, 400 ⁇ m thick Whatman glass fiber filter paper and electrolyte E8 sandwiched between the two are housed in a battery case (CR 2032 type coin cell case manufactured by Hosen Co., Ltd.) with a diameter of 13.82 mm. A half cell was constructed. This was designated as a half cell of Battery D-5.
  • Battery D-6 A half cell of the battery D-6 was produced in the same manner as the battery D-5 except that the electrolytic solution E11 was used.
  • Battery D-7 A half cell of Battery D-7 was produced in the same manner as Battery D-5, except that Electrolyte E16 was used.
  • Battery D-8 A half cell of the battery D-8 was produced in the same manner as the battery D-5, except that the electrolytic solution E19 was used.
  • Battery D-C3 A half cell of Battery D-C3 was produced in the same manner as Battery D-5, except that the electrolyte solution of Electrolyte C5 was used.
  • the half cells of the batteries D-5 to D-8 are reversibly charged and discharged similarly to the half cells of the battery D-C3 using a general electrolytic solution. I understand.

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Abstract

The positive electrode of this nonaqueous secondary battery comprises a positive electrode active material that contains at least one material selected from among lithium metal composite oxides having a layered rock salt structure, lithium metal composite oxides having a spinel structure and polyanion-based materials. The electrolyte solution of this nonaqueous secondary battery contains a metal salt, wherein an alkali metal, an alkaline earth metal or aluminum serves as cations, and an organic solvent having a hetero element. With respect to the peak intensity ascribed to the organic solvent in a vibrational spectrum of the electrolyte solution, if Io is the original peak intensity of the organic solvent and Is is the intensity of a shifted peak of the organic solvent, Io and Is satisfy Is > Io. The highest working potential of the positive electrode of this nonaqueous secondary battery may be 4.5 V or more relative to Li/Li+.

Description

非水系二次電池Non-aqueous secondary battery
　本発明は、リチウムイオン二次電池などの非水系二次電池に関する。 The present invention relates to a non-aqueous secondary battery such as a lithium ion secondary battery.
　リチウムイオン二次電池などの非水系二次電池は、小型でエネルギー密度が高く、ポータブル電子機器の電源として広く用いられている。リチウムイオン二次電池の正極活物質としては、主としてＬｉＣｏＯ２、ＬｉＮｉＯ２、Ｌｉ（ＮｉｘＣｏｙＭｎｚ）Ｏ２（ｘ+ｙ+ｚ＝１）などの層状岩塩構造をもつリチウム金属複合酸化物が用いられている（特許文献１）。電解液は、エチレンカーボネートを含む有機溶媒にリチウム塩を溶解させることで作製される。 Non-aqueous secondary batteries such as lithium ion secondary batteries are small and have high energy density, and are widely used as power sources for portable electronic devices. As the positive electrode active material of the lithium ion secondary battery mainly lithium metal composite oxide with LiCoO 2, LiNiO 2, Li ( Ni x Co y Mn z) O 2 (x + y + z = 1) layered rock salt structure, such as The thing is used (patent document 1). The electrolytic solution is produced by dissolving a lithium salt in an organic solvent containing ethylene carbonate.
　一般的には、充電状態では、上記のリチウム金属複合酸化物は、放電状態に比べ構造が不安定になる。熱などのエネルギーを加えると結晶構造の崩壊と共に、酸素（Ｏ）を放出し、放出した酸素が電解液と反応して燃焼発熱すると考えられている。 Generally, in the charged state, the above lithium metal composite oxide has an unstable structure compared to the discharged state. When energy such as heat is applied, it is considered that oxygen (O) is released along with the collapse of the crystal structure, and the released oxygen reacts with the electrolytic solution to generate combustion heat.
　層状岩塩構造をもつリチウム金属複合酸化物の中でも特にＬｉＮｉＯ２やＮｉ比率の高いＬｉ（ＮｉｘＣｏｙＭｎｚ）Ｏ２は、ＬｉＣｏＯ２などに比べて材料コストが低く、また取り出せる電流容量が大きいという利点がある。その反面、Ｎｉ量の増大に伴い、充電状態での電解液との反応性が高まり、過熱した際の電解液と正極の反応による発熱開始温度が低下することが報告されている（非特許文献１）。これらのリチウム金属複合酸化物を揮発性の電解液とともに用いると、電池に損傷が発生した場合に、過熱された電解液が瞬時に系外に放出されるおそれがある。 High Li (Ni x Co y Mn z ) O 2 otherwise LiNiO 2, Ni ratio among the lithium metal composite oxide having a layered rock salt structure, material cost is low and the current capacity that can be extracted is larger than that, such as LiCoO 2 There is an advantage. On the other hand, it has been reported that as the amount of Ni increases, the reactivity with the electrolyte in the charged state increases, and the heat generation start temperature due to the reaction between the electrolyte and the positive electrode when overheated decreases (non-patent document 1). When these lithium metal composite oxides are used together with a volatile electrolyte, when the battery is damaged, the overheated electrolyte may be instantaneously released outside the system.
　例えば、電解液に広く用いられるエチレンカーボネートを含む混合有機溶媒は、電解液の粘度および融点が低く、高いイオン伝導度を有する電解液となる一方、揮発しやすい。万が一、電池に隙間があった場合や損傷などが発生した場合には、電池系外に瞬時に気体として放出されるおそれがある。 For example, a mixed organic solvent containing ethylene carbonate, which is widely used for an electrolytic solution, is low in viscosity and melting point of the electrolytic solution and becomes an electrolytic solution having a high ionic conductivity, but is easily volatilized. In the unlikely event that there is a gap or damage in the battery, there is a risk that it will be instantaneously released as a gas outside the battery system.
　電解液としてイオン液体のような低揮発性液体を用いることで、電池に損傷が発生した場合に電解液の揮発を抑えることが考えられる。しかし、イオン液体は、粘度が高くイオン伝導度が通常の電解液と比べて低い。このため、電池の入出力特性を悪くする。 By using a low volatile liquid such as an ionic liquid as the electrolytic solution, it is conceivable to suppress the volatilization of the electrolytic solution when the battery is damaged. However, the ionic liquid has a high viscosity and a low ionic conductivity compared to a normal electrolytic solution. For this reason, the input / output characteristics of the battery are deteriorated.
　本願発明者は、電解液について鋭意探求し、新たな低揮発性の電解液を開発した。そして、本願発明者は、この新たな電解液を、リチウム金属複合酸化物を活物質とする正極と組み合わせると、入出力特性の優れた非水系二次電池が得られることを見いだした。 The inventor of the present application eagerly searched for an electrolytic solution and developed a new low-volatile electrolytic solution. The inventors of the present application have found that a non-aqueous secondary battery having excellent input / output characteristics can be obtained by combining this new electrolyte with a positive electrode using a lithium metal composite oxide as an active material.
　また、リチウムイオン二次電池の正極活物質としては、主としてＬｉＭｎ２Ｏ４などのスピネル構造をもつリチウム金属複合酸化物が用いられることがある。電解液は、リチウム塩を、エチレンカーボネートを含む溶媒に溶解してなる（特許文献１，２）。
　このような二次電池では、負極、正極共に可逆的に充放電反応が行われる必要がある。 Moreover, as a positive electrode active material of a lithium ion secondary battery, a lithium metal composite oxide having a spinel structure such as LiMn 2 O 4 may be mainly used. The electrolytic solution is obtained by dissolving a lithium salt in a solvent containing ethylene carbonate (Patent Documents 1 and 2).
In such a secondary battery, both the negative electrode and the positive electrode need to be reversibly charged and discharged.
　また、リチウムイオン二次電池の正極活物質としては、ＬｉＦｅＰＯ４などのオリビン構造をもつポリアニオン系材料が用いられることがある。オリビン系活物質を使用した電池は安全性、サイクル性に優れ、安価であるという特徴を持つ。電解液は、金属塩を、エチレンカーボネートを含む溶媒に溶解してなる（特許文献３、４）。 Moreover, as a positive electrode active material of a lithium ion secondary battery, a polyanion material having an olivine structure such as LiFePO 4 may be used. A battery using an olivine-based active material is characterized by excellent safety, cycleability, and low cost. The electrolytic solution is obtained by dissolving a metal salt in a solvent containing ethylene carbonate (Patent Documents 3 and 4).
　このような二次電池では、負極、正極共に可逆的に充放電反応が行われる必要がある。また、高いレート容量特性が望まれている。 In such a secondary battery, both the negative electrode and the positive electrode need to be reversibly charged and discharged. In addition, high rate capacity characteristics are desired.
　また、リチウムイオン二次電池の正極活物質としては、主としてＬｉＣｏＯ２、ＬｉＮｉＯ２、Ｌｉ（ＮｉｘＣｏｙＭｎｚ）Ｏ２（ｘ+ｙ+ｚ＝１）などの層状岩塩構造をもつリチウム金属複合酸化物、ＬｉＭｎ２Ｏ４などのスピネル型酸化物、ＬｉＦｅＰＯ４、Ｌｉ２ＭｎＳｉＯ４などのポリアニオン化合物が用いられることがある。電解液は、リチウム塩を、エチレンカーボネートを含む溶媒に溶解してなる（特許文献１、２）。 As the positive electrode active material of a lithium ion secondary battery, lithium metal mainly with LiCoO 2, LiNiO 2, Li ( Ni x Co y Mn z) O 2 (x + y + z = 1) layered rock salt structure, such as composite oxide, spinel oxides such as LiMn 2 O 4, may be polyanionic compound, such as LiFePO 4, Li 2 MnSiO 4 is used. The electrolytic solution is obtained by dissolving a lithium salt in a solvent containing ethylene carbonate (Patent Documents 1 and 2).
　一般的にリチウムイオン二次電池は、充放電反応を可逆的に行う。このためには、電解液には高い耐還元性と、耐酸化性が求められる。特に、非水系二次電池において高い容量を得ようとする場合や、正極に５Ｖ（ｖｓ　Ｌｉ＋／Ｌｉ）付近で可逆的な充放電反応をする活物質を用いた場合は、電池本体の使用可能上限電位を上昇させる必要がある。この場合、電解液は正極の使用最高電位を上回る高い酸化分解電位を有することが望まれる。 Generally, a lithium ion secondary battery performs a charge / discharge reaction reversibly. For this purpose, the electrolytic solution is required to have high reduction resistance and oxidation resistance. In particular, when a high capacity is to be obtained in a non-aqueous secondary battery, or when an active material that reversibly charges and discharges near 5 V (vs Li + / Li) is used for the positive electrode, the battery body is used. It is necessary to increase the upper limit potential. In this case, it is desirable that the electrolytic solution has a high oxidative decomposition potential that exceeds the maximum use potential of the positive electrode.
　そこで、特許文献５では、高い反応電位を有する化合物を電解液に添加することが提案されている。 Therefore, Patent Document 5 proposes to add a compound having a high reaction potential to the electrolytic solution.
　本発明者は、鋭意探求の結果、従来技術とは異なった手法で高い耐酸化性を有する電解液を開発した。 As a result of diligent research, the present inventor has developed an electrolytic solution having high oxidation resistance by a method different from the conventional technique.
国際公開２０１１／１１１３６４International Publication 2011-111364 特開２０１３－８２５８１号公報JP 2013-82581 A 特開２０１３－６５５７５号公報JP 2013-65575 A 特開２００９－１２３４７４号公報JP 2009-123474 A 特表２００８－５０１２２０号公報Special table 2008-501220 gazette
　本発明はかかる事情に鑑みてなされたものであり、第１の課題は、優れた入出力特性をもつ非水系二次電池を提供することである。 The present invention has been made in view of such circumstances, and a first problem is to provide a non-aqueous secondary battery having excellent input / output characteristics.
　第２の課題は、安全性の向上と、可逆的な充放電反応が可能であることを両立させる非水系二次電池を提供することである。 The second problem is to provide a non-aqueous secondary battery that achieves both improved safety and reversible charge / discharge reaction.
　第３の課題は、可逆的な充放電反応が可能でレート容量特性が向上する新規な電解液と正極の組み合わせを持つ非水系二次電池を提供することである。 A third problem is to provide a non-aqueous secondary battery having a novel electrolyte solution and positive electrode combination capable of reversible charge / discharge reaction and improving rate capacity characteristics.
　第４の課題は、高電位で使用可能な非水系二次電池を提供することである。 The fourth problem is to provide a non-aqueous secondary battery that can be used at a high potential.
　本発明の第１の態様に係る非水系二次電池は、正極と負極と電解液とを有する非水系二次電池であって、
　前記正極は、層状岩塩構造をもつリチウム金属複合酸化物を有する正極活物質をもち、
　前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、
　前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする。
　本発明の第１の態様は、本発明者が、鋭意探求の結果、層状岩塩構造をもつリチウム金属複合酸化物を有する正極を備える非水系二次電池について、可逆的に充放電反応が可能で、入出力特性に優れる新規な電解液を開発したことによる。 The non-aqueous secondary battery according to the first aspect of the present invention is a non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolyte solution,
The positive electrode has a positive electrode active material having a lithium metal composite oxide having a layered rock salt structure,
The electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element,
Regarding the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io. Features.
The first aspect of the present invention is that, as a result of earnest search, the inventor can reversibly charge and discharge a non-aqueous secondary battery including a positive electrode having a lithium metal composite oxide having a layered rock salt structure. This is due to the development of a new electrolyte with excellent input / output characteristics.
　本発明の第２の態様に係る非水系二次電池は、正極と負極と電解液とを有する非水系二次電池であって、前記正極は、スピネル構造をもつリチウム金属複合酸化物を有する正極活物質をもち、前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする。 The non-aqueous secondary battery according to the second aspect of the present invention is a non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolytic solution, and the positive electrode has a lithium metal composite oxide having a spinel structure. The electrolyte solution has an active material, and the electrolyte solution includes a metal salt having a cation of alkali metal, alkaline earth metal, or aluminum, and an organic solvent having a hetero element, and is derived from the organic solvent in a vibrational spectrum of the electrolyte solution. Regarding the peak intensity, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io.
　本発明の第２の態様は、本発明者が、鋭意探求の結果、スピネル構造をもつリチウム金属複合酸化物をもつ正極を備える非水系二次電池について、可逆的に充放電反応が可能な新規な電解液を開発したことによる。 According to a second aspect of the present invention, as a result of intensive research, the present inventor is a novel capable of reversibly charging and discharging a non-aqueous secondary battery including a positive electrode having a lithium metal composite oxide having a spinel structure. Because of the development of a new electrolyte.
　本発明の第３の態様に係る非水系二次電池は、正極と負極と電解液とを有する非水系二次電池であって、前記正極は、ポリアニオン系材料を有する正極活物質をもち、前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする。 A non-aqueous secondary battery according to a third aspect of the present invention is a non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode has a positive electrode active material having a polyanion material, The electrolytic solution includes a metal salt having an alkali metal, alkaline earth metal, or aluminum as a cation and an organic solvent having a hetero element, and the organic solvent has a peak intensity derived from the organic solvent in a vibrational spectrum of the electrolytic solution. When the intensity of the original peak of the solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io.
　本発明の第３の態様は、本発明者が、鋭意探求の結果、ポリアニオン系材料をもつ正極を備える非水系二次電池について、可逆的に充放電反応が可能でレート容量特性が向上する新規な電解液と正極の組み合わせを開発したことによる。 According to a third aspect of the present invention, as a result of intensive research, the inventor has developed a novel non-aqueous secondary battery including a positive electrode having a polyanion-based material that can reversibly charge and discharge and improve rate capacity characteristics. This is due to the development of a combination of electrolyte and positive electrode.
　本発明の第４の態様に係る非水系二次電池は、正極活物質を有する正極と、負極活物質を有する負極と、電解液とを有する非水系二次電池であって、
　前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、
　前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであって、
　前記非水系二次電池は、Ｌｉ／Ｌｉ＋を基準電位としたときの正極の使用最高電位が４．５Ｖ以上であることを特徴とする。 A non-aqueous secondary battery according to a fourth aspect of the present invention is a non-aqueous secondary battery having a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and an electrolyte solution,
The electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element,
With respect to the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io,
The non-aqueous secondary battery is characterized in that the maximum usable potential of the positive electrode when Li / Li + is used as a reference potential is 4.5 V or more.
　本発明の第１の態様によれば、上記の電解液を用いているため、優れた入出力特性をもつ非水系二次電池を提供することができる。 According to the first aspect of the present invention, since the above electrolytic solution is used, a nonaqueous secondary battery having excellent input / output characteristics can be provided.
　本発明の第２の態様によれば、上記の新規な電解液を用いているため、安全性の向上と、可逆的な充放電反応が可能であることを両立させる非水系二次電池を提供することができる。 According to the second aspect of the present invention, there is provided a non-aqueous secondary battery that achieves both improvement in safety and reversible charge / discharge reaction since the above-described novel electrolytic solution is used. can do.
　本発明の第３の態様によれば、上記の新規な電解液を用いているため、可逆的に充放電反応が可能でレート容量特性が向上する新規な電解液と正極の組み合わせを持つ非水系二次電池を提供することができる。 According to the third aspect of the present invention, since the above-described novel electrolyte is used, a non-aqueous system having a combination of a novel electrolyte and a positive electrode that can reversibly charge and discharge and improve rate capacity characteristics. A secondary battery can be provided.
　本発明の第４の態様の非水系二次電池によれば、上記の電解液をもつため、高電位で使用することができ、平均電圧や電池容量が増大する。 According to the non-aqueous secondary battery of the fourth aspect of the present invention, since it has the above electrolyte, it can be used at a high potential, and the average voltage and battery capacity increase.
電解液Ｅ３のＩＲスペクトルである。It is IR spectrum of the electrolyte solution E3. 電解液Ｅ４のＩＲスペクトルである。It is IR spectrum of the electrolyte solution E4. 電解液Ｅ７のＩＲスペクトルである。It is IR spectrum of the electrolyte solution E7. 電解液Ｅ８のＩＲスペクトルである。It is IR spectrum of the electrolyte solution E8. 電解液Ｅ１０のＩＲスペクトルである。It is IR spectrum of the electrolyte solution E10. 電解液Ｃ２のＩＲスペクトルである。It is IR spectrum of the electrolyte solution C2. 電解液Ｃ４のＩＲスペクトルである。It is IR spectrum of the electrolyte solution C4. アセトニトリルのＩＲスペクトルである。It is IR spectrum of acetonitrile. （ＣＦ３ＳＯ２）２ＮＬｉのＩＲスペクトルである。It is an IR spectrum of (CF 3 SO 2 ) 2 NLi. （ＦＳＯ２）２ＮＬｉのＩＲスペクトルである（２１００～２４００ｃｍ－１）。It is an IR spectrum of (FSO 2 ) 2 NLi (2100 to 2400 cm −1 ). 電解液Ｅ１１の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E11. 電解液Ｅ１２の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E12. 電解液Ｅ１３の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E13. 電解液Ｅ１４の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E14. 電解液Ｅ１５の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E15. 電解液Ｃ６の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution C6. ジメチルカーボネートのＩＲスペクトルである。It is IR spectrum of dimethyl carbonate. 電解液Ｅ１６の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E16. 電解液Ｅ１７の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E17. 電解液Ｅ１８の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E18. 電解液Ｃ７の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution C7. エチルメチルカーボネートのＩＲスペクトルである。It is IR spectrum of ethyl methyl carbonate. 電解液Ｅ１９の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E19. 電解液Ｅ２０の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E20. 電解液Ｅ２１の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution E21. 電解液Ｃ８の電解液のＩＲスペクトルである。It is IR spectrum of the electrolyte solution of the electrolyte solution C8. ジエチルカーボネートのＩＲスペクトルである。It is IR spectrum of diethyl carbonate. （ＦＳＯ２）２ＮＬｉのＩＲスペクトルである（１９００～１６００ｃｍ－１）。It is an IR spectrum of (FSO 2 ) 2 NLi (1900-1600 cm −1 ). 電解液Ｅ８のラマンスペクトルである。It is a Raman spectrum of the electrolyte solution E8. 電解液Ｅ９のラマンスペクトルである。It is a Raman spectrum of the electrolyte solution E9. 電解液Ｃ４のラマンスペクトルである。It is a Raman spectrum of the electrolyte solution C4. 電解液Ｅ１１のラマンスペクトルである。It is a Raman spectrum of the electrolyte solution E11. 電解液Ｅ１３のラマンスペクトルである。It is a Raman spectrum of the electrolyte solution E13. 電解液Ｅ１５のラマンスペクトルである。It is a Raman spectrum of the electrolyte solution E15. 電解液Ｃ６のラマンスペクトルである。It is a Raman spectrum of the electrolyte solution C6. 実施例Ａ－１と比較例Ａ－１のＤＳＣ曲線を示す。2 shows DSC curves of Example A-1 and Comparative Example A-1. 実施例Ａ－２と比較例Ａ－１のＤＳＣ曲線を示す。2 shows DSC curves of Example A-2 and Comparative Example A-1. 実施例Ａ－５、比較例Ａ－３のリチウムイオン二次電池について、サイクル試験時におけるサイクル数の平方根と放電容量維持率との関係を示すグラフである。6 is a graph showing the relationship between the square root of the number of cycles during a cycle test and the discharge capacity retention rate for the lithium ion secondary batteries of Example A-5 and Comparative Example A-3. 評価例Ａ－１５における、電池の複素インピーダンス平面プロットである。18 is a complex impedance plane plot of a battery in Evaluation Example A-15. 評価例Ａ－１６における、電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３の負極Ｓ，Ｏ含有皮膜の炭素元素についてのＸＰＳ分析結果である。10 is an XPS analysis result of carbon elements in negative electrode S, O-containing coating films of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16. 評価例Ａ－１６における、電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３の負極Ｓ，Ｏ含有皮膜のフッ素元素についてのＸＰＳ分析結果である。FIG. 10 is an XPS analysis result of fluorine element in negative electrode S, O-containing coating film of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16. 評価例Ａ－１６における、電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３の負極Ｓ，Ｏ含有皮膜の窒素元素についてのＸＰＳ分析結果である。10 is an XPS analysis result of nitrogen element in negative electrode S, O-containing coating film of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16. 評価例Ａ－１６における、電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３の負極Ｓ，Ｏ含有皮膜の酸素元素についてのＸＰＳ分析結果である。10 is an XPS analysis result of oxygen elements in negative electrode S and O-containing films of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16. 評価例Ａ－１６における、電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３の負極Ｓ，Ｏ含有皮膜の硫黄元素についてのＸＰＳ分析結果である。10 is an XPS analysis result of sulfur element in negative electrode S, O-containing coating film of Battery A-8, Battery A-9, and Battery A-C3 in Evaluation Example A-16. 評価例Ａ－１６における電池Ａ－８の負極Ｓ，Ｏ含有皮膜のＸＰＳ分析結果である。10 is an XPS analysis result of a negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-16. 評価例Ａ－１９における電池Ａ－９の負極Ｓ，Ｏ含有皮膜のＸＰＳ分析結果である。20 shows the result of XPS analysis of a negative electrode S, O-containing film of Battery A-9 in Evaluation Example A-19. 評価例Ａ－１９における電池Ａ－８の負極Ｓ，Ｏ含有皮膜のＢＦ－ＳＴＥＭ像である。19 is a BF-STEM image of a negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－８の負極Ｓ，Ｏ含有皮膜のＣについてのＳＴＥＭ分析結果である。19 shows the STEM analysis result for C of the negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－８の負極Ｓ，Ｏ含有皮膜のＯについてのＳＴＥＭ分析結果である。19 shows the results of STEM analysis on O of the negative electrode S, O-containing film of Battery A-8 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－８の負極Ｓ，Ｏ含有皮膜のＳについてのＳＴＥＭ分析結果である。19 shows STEM analysis results on S of negative electrode S and O-containing coating film of Battery A-8 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－８の正極Ｓ，Ｏ含有皮膜のＯについてのＸＰＳ分析結果である。19 shows the XPS analysis result for O of the positive electrode S, O-containing film of Battery A-8 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－８の正極Ｓ，Ｏ含有皮膜のＳについてのＸＰＳ分析結果である。19 shows the XPS analysis result for S of the positive electrode S, O-containing film of Battery A-8 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１１の正極Ｓ，Ｏ含有皮膜のＳについてのＸＰＳ分析結果である。19 shows the XPS analysis result for S of the positive electrode S, O-containing film of battery A-11 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１１の正極Ｓ，Ｏ含有皮膜のＯについてのＸＰＳ分析結果である。19 shows the XPS analysis result for O of the positive electrode S, O-containing film of battery A-11 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１１、電池Ａ－１２および電池Ａ－Ｃ４の正極Ｓ，Ｏ含有皮膜のＳについてのＸＰＳ分析結果である。19 shows the XPS analysis results for S of the positive electrode S and O-containing films of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１３、電池Ａ－１４および電池Ａ－Ｃ５の正極Ｓ，Ｏ含有皮膜のＳについてのＸＰＳ分析結果である。20 shows XPS analysis results for S of positive electrode S and O-containing coatings of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１１、電池Ａ－１２および電池Ａ－Ｃ４の正極Ｓ，Ｏ含有皮膜のＯについてのＸＰＳ分析結果である。19 shows the XPS analysis result for O of the positive electrode S, O-containing coating film of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１３、電池Ａ－１４および電池Ａ－Ｃ５の正極Ｓ，Ｏ含有皮膜のＯについての分析結果である。19 shows the analysis results on O of the positive electrode S and O-containing coatings of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１１、電池Ａ－１２および電池Ａ－Ｃ４の負極Ｓ，Ｏ含有皮膜のＳについての分析結果である。19 shows the analysis results on S of negative electrode S and O-containing films of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１３、電池Ａ－１４および電池Ａ－Ｃ５の負極Ｓ，Ｏ含有皮膜のＳについての分析結果である。19 shows the analysis results on S of the negative electrode S and O-containing coating film of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１１、電池Ａ－１２および電池Ａ－Ｃ４の負極Ｓ，Ｏ含有皮膜のＯについての分析結果である。19 shows the analysis results on O of the negative electrode S and O-containing films of Battery A-11, Battery A-12, and Battery A-C4 in Evaluation Example A-19. 評価例Ａ－１９における、電池Ａ－１３、電池Ａ－１４および電池Ａ－Ｃ５の負極Ｓ，Ｏ含有皮膜のＯについての分析結果である。19 shows the analysis results on O of the negative electrode S and O-containing films of Battery A-13, Battery A-14, and Battery A-C5 in Evaluation Example A-19. 評価例Ａ－２１における、電池Ａ－８のリチウムイオン二次電池の充放電後のアルミニウム箔の表面分析結果である。7 is a surface analysis result of an aluminum foil after charge / discharge of a lithium ion secondary battery of Battery A-8 in Evaluation Example A-21. 評価例Ａ－２１における、電池Ａ－９のリチウムイオン二次電池の充放電後のアルミニウム箔の表面分析結果である。7 is a surface analysis result of an aluminum foil after charge / discharge of a lithium ion secondary battery of Battery A-9 in Evaluation Example A-21. 電池A１のハーフセルに対する電位（３．１～４．６Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of battery A1 and a response current. 電池A１のハーフセルに対する電位（３．１～５．１Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of battery A1. 電池A２のハーフセルに対する電位（３．１～４．６Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of battery A2 and a response current. 電池A２のハーフセルに対する電位（３．１～５．１Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of battery A2. 電池A３のハーフセルに対する電位（３．１～４．６Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of a battery A3 and a response current. 電池A３のハーフセルに対する電位（３．１～５．１Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of a battery A3. 電池A４のハーフセルに対する電位（３．１～４．６Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of a battery A4 and a response current. 電池A４のハーフセルに対する電位（３．１～５．１Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 5.1 V) and a response current with respect to a half cell of a battery A4. 電池AＣ１のハーフセルに対する電位（３．１～４．６Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.1 to 4.6 V) with respect to a half cell of battery AC1 and a response current. 電池A２のハーフセルに対する電位（３．０～４．５Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.0 to 4.5 V) and a response current with respect to a half cell of battery A2. 電池A２のハーフセルに対する電位（３．０～５．０Ｖ）と応答電流との関係を示すグラフである。3 is a graph showing a relationship between a potential (3.0 to 5.0 V) and a response current with respect to a half cell of battery A2. 電池A５のハーフセルに対する電位（３．０～４．５Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.0 to 4.5 V) and a response current with respect to a half cell of battery A5. 電池A５のハーフセルに対する電位（３．０～５．０Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.0 to 5.0 V) and a response current with respect to a half cell of battery A5. 電池AＣ２のハーフセルに対する電位（３．０～４．５Ｖ）と応答電流との関係を示すグラフである。6 is a graph showing a relationship between a potential (3.0 to 4.5 V) and a response current with respect to a half cell of battery AC2. 電池AＣ２のハーフセルに対する電位（３．０～５．０Ｖ）と応答電流との関係を示すグラフである。3 is a graph showing a relationship between a potential (3.0 to 5.0 V) and a response current with respect to a half cell of battery AC2. ハーフセルのＣＶ測定結果を示す図である。It is a figure which shows the CV measurement result of a half cell. ハーフセルの充放電曲線を示す。The charging / discharging curve of a half cell is shown. 実施例Ｃ－１のハーフセルの放電曲線を示す図である。It is a figure which shows the discharge curve of the half cell of Example C-1. 比較例Ｃ－１のハーフセルの放電曲線を示す図である。It is a figure which shows the discharge curve of the half cell of the comparative example C-1. 実施例Ｃ－２のハーフセルの充放電曲線を示す図である。It is a figure which shows the charging / discharging curve of the half cell of Example C-2. 実施例Ｃ－２、Ｃ－３及び比較例Ｃ－１、Ｃ－２のハーフセルの充放電サイクルに伴う放電レート容量の変化を示す図である。It is a figure which shows the change of the discharge rate capacity | capacitance accompanying the charging / discharging cycle of the half cell of Example C-2, C-3 and Comparative Example C-1, C-2. 実施例Ｃ－１のハーフセルの各レートでの充放電曲線を示す図である。It is a figure which shows the charging / discharging curve in each rate of the half cell of Example C-1. 比較例Ｃ－１のハーフセルの各レートでの充放電曲線を示す図である。It is a figure which shows the charging / discharging curve in each rate of the half cell of the comparative example C-1. 電池Ｄ－１及び電池Ｄ－Ｃ１，Ｄ－Ｃ２のＬＳＶ測定による電位－電流曲線を示す。The potential-current curve by LSV measurement of the battery D-1 and the batteries D-C1 and D-C2 is shown. 電池Ｄ－２のＬＳＶ測定による電位－電流曲線を示す。The potential-current curve by LSV measurement of the battery D-2 is shown. 電池Ｄ－３のハーフセルの充放電曲線を示す。The charging / discharging curve of the half cell of battery D-3 is shown. 電池Ｄ－４のハーフセルの充放電曲線を示す。The charging / discharging curve of the half cell of battery D-4 is shown. リチウム金属複合酸化物の充電曲線のモデル説明図を示す。The model explanatory drawing of the charge curve of lithium metal complex oxide is shown. 電池Ｄ－５のハーフセルの充放電曲線である。It is a charging / discharging curve of the half cell of the battery D-5. 電池Ｄ－６のハーフセルの充放電曲線である。It is a charging / discharging curve of the half cell of the battery D-6. 電池Ｄ－７のハーフセルの充放電曲線である。It is a charging / discharging curve of the half cell of the battery D-7. 電池Ｄ－８のハーフセルの充放電曲線である。It is a charging / discharging curve of the half cell of the battery D-8. 電池Ｄ－Ｃ３のハーフセルの充放電曲線である。6 is a charge / discharge curve of a half cell of battery D-C3.
　本発明の第１～第４の態様に係る非水系二次電池について詳細に説明する。なお、特に断らない限り、本明細書に記載された数値範囲「ａ～ｂ」は、下限ａおよび上限ｂをその範囲に含む。そして、これらの上限値および下限値、ならびに実施例中に列記した数値も含めてそれらを任意に組み合わせることで数値範囲を構成し得る。さらに数値範囲内から任意に選択した数値を上限、下限の数値とすることができる。 The nonaqueous secondary battery according to the first to fourth aspects of the present invention will be described in detail. Unless otherwise specified, the numerical range “a to b” described in this specification includes the lower limit “a” and the upper limit “b”. The numerical range can be configured by arbitrarily combining these upper limit value and lower limit value and the numerical values listed in the examples. Furthermore, numerical values arbitrarily selected from the numerical value range can be used as upper and lower numerical values.
　(電解液)
　電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする塩（以下、「金属塩」又は単に「塩」ということがある。）と、ヘテロ元素を有する有機溶媒とを含む電解液であって、電解液の振動分光スペクトルにおける有機溶媒由来のピーク強度につき、有機溶媒本来のピーク波数におけるピークの強度をＩｏとし、有機溶媒本来のピークが波数シフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする。
　なお、従来の電解液は、ＩｓとＩｏとの関係がＩｓ＜Ｉｏである。
　以下、アルカリ金属、アルカリ 土類金属又はアルミニウムをカチオンとする塩と、ヘテロ元素を有する有機溶媒とを含む電解液であって、電解液の振動分光スペクトルにおける有機溶媒由来のピーク強度につき、有機溶媒本来のピークの強度をＩｏとし、ピークがシフトしたピークの強度をＩｓとした場合、 Ｉｓ＞Ｉｏである電解液のことを、「本発明の電解液」ということがある。 (Electrolyte)
The electrolytic solution is an electrolytic solution containing a salt having alkali metal, alkaline earth metal or aluminum as a cation (hereinafter sometimes referred to as “metal salt” or simply “salt”) and an organic solvent having a hetero element. When the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolytic solution is Io, the peak intensity at the peak wavelength of the organic solvent is Io, and the peak intensity at which the peak of the organic solvent is shifted is Is, Is> Io.
In the conventional electrolytic solution, the relationship between Is and Io is Is <Io.
Hereinafter, an electrolytic solution containing a salt having alkali metal, alkaline earth metal or aluminum as a cation and an organic solvent having a hetero element, the organic solvent having a peak intensity derived from the organic solvent in the vibrational spectrum of the electrolytic solution. When the original peak intensity is Io and the peak shifted peak intensity is Is, an electrolyte solution with Is> Io may be referred to as “the electrolyte solution of the present invention”.
　金属塩は、通常、電池の電解液に含まれるＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｌＣｌ４、などの電解質として用いられる化合物であれば良い。金属塩のカチオンとしては、リチウム、ナトリウム、カリウムなどのアルカリ金属、ベリリウム、マグネシウム、カルシウム、ストロンチウム、バリウムなどのアルカリ土類金属、及びアルミニウムを挙げることができる。金属塩のカチオンは、電解液を使用する電池の電荷担体と同一の金属イオンであるのが好ましい。例えば、本発明の電解液をリチウムイオン二次電池用の電解液として使用するのであれば、金属塩のカチオンはリチウムが好ましい。 The metal salt may be a compound that is usually used as an electrolyte, such as LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiAlCl 4 , etc. contained in the battery electrolyte. Examples of the cation of the metal salt include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium, and aluminum. The cation of the metal salt is preferably the same metal ion as the charge carrier of the battery using the electrolytic solution. For example, if the electrolytic solution of the present invention is used as an electrolytic solution for a lithium ion secondary battery, the metal salt cation is preferably lithium.
　塩のアニオンの化学構造は、ハロゲン、ホウ素、窒素、酸素、硫黄又は炭素から選択される少なくとも１つの元素を含むと良い。ハロゲン又はホウ素を含むアニオンの化学構造を具体的に例示すると、ＣｌＯ４、ＰＦ６、ＡｓＦ６、ＳｂＦ６、ＴａＦ６、ＢＦ４、ＳｉＦ６、Ｂ（Ｃ６Ｈ５）４、Ｂ（ｏｘａｌａｔｅ）２、Ｃｌ、Ｂｒ、Ｉを挙げることができる。 The chemical structure of the anion of the salt may include at least one element selected from halogen, boron, nitrogen, oxygen, sulfur or carbon. Specific examples of the chemical structure of an anion containing halogen or boron include ClO 4 , PF 6 , AsF 6 , SbF 6 , TaF 6 , BF 4 , SiF 6 , B (C 6 H 5 ) 4 , and B (oxalate). 2 , Cl, Br, and I.
　窒素、酸素、硫黄又は炭素を含むアニオンの化学構造について、以下、具体的に説明する。 The chemical structure of an anion containing nitrogen, oxygen, sulfur or carbon will be specifically described below.
　塩のアニオンの化学構造は、下記一般式（１）、一般式（２）又は一般式（３）で表される化学構造が好ましい。
（Ｒ１Ｘ１）（Ｒ２Ｘ２）Ｎ　　　　　　　　　　　　一般式（１）
（Ｒ１は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　Ｒ２は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒ１とＲ２は、互いに結合して環を形成しても良い。
　Ｘ１は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲａＰ＝Ｏ、ＲｂＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｘ２は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｃＰ＝Ｏ、ＲｄＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｒａ、Ｒｂ、Ｒｃ、Ｒｄは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒａ、Ｒｂ、Ｒｃ、Ｒｄは、Ｒ１又はＲ２と結合して環を形成しても良い。）
Ｒ３Ｘ３Ｙ　　　　　　　　　　　　一般式（２）
（Ｒ３は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　Ｘ３は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｅＰ＝Ｏ、ＲｆＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｒｅ、Ｒｆは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒｅ、Ｒｆは、Ｒ３と結合して環を形成しても良い。
　Ｙは、Ｏ、Ｓから選択される。）
（Ｒ４Ｘ４）（Ｒ５Ｘ５）（Ｒ６Ｘ６）Ｃ　　　　　　　　　　　　一般式（３）
（Ｒ４は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　Ｒ５は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　Ｒ６は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒ４、Ｒ５、Ｒ６のうち、いずれか２つ又は３つが結合して環を形成しても良い。
　Ｘ４は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｇＰ＝Ｏ、ＲｈＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｘ５は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｉＰ＝Ｏ、ＲｊＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｘ６は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｋＰ＝Ｏ、ＲｌＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｒｇ、Ｒｈ、Ｒｉ、Ｒｊ、Ｒｋ、Ｒｌは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒｇ、Ｒｈ、Ｒｉ、Ｒｊ、Ｒｋ、Ｒｌは、Ｒ４、Ｒ５又はＲ６と結合して環を形成しても良い。）
　上記一般式（１）～（３）で表される化学構造における、「置換基で置換されていても良い」との文言について説明する。例えば「置換基で置換されていても良いアルキル基」であれば、アルキル基の水素の一つ若しくは複数が置換基で置換されているアルキル基、又は、特段の置換基を有さないアルキル基を意味する。
　「置換基で置換されていても良い」との文言における置換基としては、アルキル基、アルケニル基、アルキニル基、シクロアルキル基、不飽和シクロアルキル基、芳香族基、複素環基、ハロゲン、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮ、ニトロ基、アルコキシ基、不飽和アルコキシ基、アミノ基、アルキルアミノ基、ジアルキルアミノ基、アリールオキシ基、アシル基、アルコキシカルボニル基、アシルオキシ基、アリールオキシカルボニル基、アシルアミノ基、アルコキシカルボニルアミノ基、アリールオキシカルボニルアミノ基、スルホニルアミノ基、スルファモイル基、カルバモイル基、アルキルチオ基、アリールチオ基、スルホニル基、スルフィニル基、ウレイド基、リン酸アミド基、スルホ基、カルボキシル基、ヒドロキサム酸基、スルフィノ基、ヒドラジノ基、イミノ基、シリル基等が挙げられる。これらの置換基はさらに置換されてもよい。また置換基が２つ以上ある場合、置換基は同一でも異なっていてもよい。 The chemical structure of the anion of the salt is preferably a chemical structure represented by the following general formula (1), general formula (2), or general formula (3).
(R 1 X 1 ) (R 2 X 2 ) N General formula (1)
(R 1 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted with, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, or an alkoxy group which may be substituted with a substituent , An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
R 2 represents hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, an alkoxy group which may be substituted with a substituent, Selected from an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, CN, SCN, OCN The
R 1 and R 2 may be bonded to each other to form a ring.
X 1 is selected from SO 2 , C = O, C = S, R a P = O, R b P = S, S = O, Si = O.
X 2 is, SO 2, C = O, C = S, R c P = O, R d P = S, S = O, is selected from Si = O.
R a , R b , R c , and R d are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a substituent. An unsaturated alkyl group which may be substituted, an unsaturated cycloalkyl group which may be substituted with a substituent, an aromatic group which may be substituted with a substituent, or a heterocyclic group which may be substituted with a substituent , An alkoxy group that may be substituted with a substituent, an unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, and a non-optionally substituted substituent. Selected from saturated thioalkoxy groups, OH, SH, CN, SCN, OCN.
R a , R b , R c , and R d may be bonded to R 1 or R 2 to form a ring. )
R 3 X 3 Y General formula (2)
(R 3 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted with, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, or an alkoxy group which may be substituted with a substituent , An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
X 3 is selected from SO 2 , C = O, C = S, R e P = O, R f P = S, S = O, and Si = O.
R e and R f are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a group that may be substituted with a substituent. A saturated alkyl group, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, a heterocyclic group that may be substituted with a substituent, and a substituent An alkoxy group which may be substituted, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, OH , SH, CN, SCN, and OCN.
R e and R f may combine with R 3 to form a ring.
Y is selected from O and S. )
(R 4 X 4) (R 5 X 5) (R 6 X 6) C Formula (3)
(R 4 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted with, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, or an alkoxy group which may be substituted with a substituent , An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
R 5 represents hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, an alkoxy group which may be substituted with a substituent, Selected from an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, CN, SCN, OCN The
R 6 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, an alkoxy group which may be substituted with a substituent, Selected from an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, CN, SCN, OCN The
Further, any two or three of R 4 , R 5 and R 6 may be bonded to form a ring.
X 4 is, SO 2, C = O, C = S, R g P = O, R h P = S, S = O, is selected from Si = O.
X 5 is selected from SO 2 , C = O, C = S, R i P = O, R j P = S, S = O, Si = O.
X 6 is selected from SO 2 , C = O, C = S, R k P = O, R 1 P = S, S = O, Si = O.
R g , R h , R i , R j , R k , and R l are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, or a cycloalkyl that may be substituted with a substituent. Group, an unsaturated alkyl group that may be substituted with a substituent, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, or a substituent that is substituted with a substituent A heterocyclic group which may be substituted, an alkoxy group which may be substituted with a substituent, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, and a substituent It is selected from an unsaturated thioalkoxy group which may be substituted, OH, SH, CN, SCN, OCN.
R g , R h , R i , R j , R k , and R l may combine with R 4 , R 5, or R 6 to form a ring. )
The term “may be substituted with a substituent” in the chemical structures represented by the general formulas (1) to (3) will be described. For example, in the case of “an alkyl group that may be substituted with a substituent”, an alkyl group in which one or more of the hydrogens of the alkyl group are substituted with a substituent, or an alkyl group that does not have a particular substituent Means.
Examples of the substituent in the phrase “may be substituted with a substituent” include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an unsaturated cycloalkyl group, an aromatic group, a heterocyclic group, a halogen, and OH. SH, CN, SCN, OCN, nitro group, alkoxy group, unsaturated alkoxy group, amino group, alkylamino group, dialkylamino group, aryloxy group, acyl group, alkoxycarbonyl group, acyloxy group, aryloxycarbonyl group, Acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group, sulfo group, carboxyl group, Hydroxamic acid group, Rufino group, a hydrazino group, an imino group, and a silyl group. These substituents may be further substituted. When there are two or more substituents, the substituents may be the same or different.
　塩のアニオンの化学構造は、下記一般式（４）、一般式（５）又は一般式（６）で表される化学構造がより好ましい。
（Ｒ７Ｘ７）（Ｒ８Ｘ８）Ｎ　　　　　　　　　　　　一般式（４）
（Ｒ７、Ｒ８は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅ（ＣＮ）ｆ（ＳＣＮ）ｇ（ＯＣＮ）ｈである。
　ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
　また、Ｒ７とＲ８は、互いに結合して環を形成しても良く、その場合は、２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
　Ｘ７は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｍＰ＝Ｏ、ＲｎＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｘ８は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｏＰ＝Ｏ、ＲｐＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｒｍ、Ｒｎ、Ｒｏ、Ｒｐは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒｍ、Ｒｎ、Ｒｏ、Ｒｐは、Ｒ７又はＲ８と結合して環を形成しても良い。）
Ｒ９Ｘ９Ｙ　　　　　　　　　　　　一般式（５）
（Ｒ９は、ＣｎＨａＦｂＣｌｃＢｒｄＩｅ（ＣＮ）ｆ（ＳＣＮ）ｇ（ＯＣＮ）ｈである。
　ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
　Ｘ９は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｑＰ＝Ｏ、ＲｒＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｒｑ、Ｒｒは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒｑ、Ｒｒは、Ｒ９と結合して環を形成しても良い。
　Ｙは、Ｏ、Ｓから選択される。）
（Ｒ１０Ｘ１０）（Ｒ１１Ｘ１１）（Ｒ１２Ｘ１２）Ｃ　　　　　　　　一般式（６）
（Ｒ１０、Ｒ１１、Ｒ１２は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅ（ＣＮ）ｆ（ＳＣＮ）ｇ（ＯＣＮ）ｈである。
　ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
　Ｒ１０、Ｒ１１、Ｒ１２のうちいずれか２つが結合して環を形成しても良く、その場合、環を形成する基は２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。また、Ｒ１０、Ｒ１１、Ｒ１２の３つが結合して環を形成しても良く、その場合、３つのうち２つの基が２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たし、１つの基が２ｎ－１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
　Ｘ１０は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｓＰ＝Ｏ、ＲｔＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｘ１１は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｕＰ＝Ｏ、ＲｖＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｘ１２は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｗＰ＝Ｏ、ＲｘＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
　Ｒｓ、Ｒｔ、Ｒｕ、Ｒｖ、Ｒｗ、Ｒｘは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
　また、Ｒｓ、Ｒｔ、Ｒｕ、Ｒｖ、Ｒｗ、Ｒｘは、Ｒ１０、Ｒ１１又はＲ１２と結合して環を形成しても良い。）
　上記一般式（４）～（６）で表される化学構造における、「置換基で置換されていても良い」との文言の意味は、上記一般式（１）～（３）で説明したのと同義である。
　上記一般式（４）～（６）で表される化学構造において、ｎは０～６の整数が好ましく、０～４の整数がより好ましく、０～２の整数が特に好ましい。なお、上記一般式（４）～（６）で表される化学構造の、Ｒ７とＲ８が結合、又は、Ｒ１０、Ｒ１１、Ｒ１２が結合して環を形成している場合には、ｎは１～８の整数が好ましく、１～７の整数がより好ましく、１～３の整数が特に好ましい。 The chemical structure of the anion of the salt is more preferably a chemical structure represented by the following general formula (4), general formula (5), or general formula (6).
(R 7 X 7 ) (R 8 X 8 ) N General formula (4)
(R 7 and R 8 are each independently C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h .
n, a, b, c, d, e, f, g, and h are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e + f + g + h.
R 7 and R 8 may combine with each other to form a ring, in which case 2n = a + b + c + d + e + f + g + h is satisfied.
X 7 is, SO 2, C = O, C = S, R m P = O, R n P = S, S = O, is selected from Si = O.
X 8 is selected from SO 2 , C = O, C = S, R o P = O, R p P = S, S = O, Si = O.
R m , R n , R o , and R p are each independently substituted with hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a substituent. An unsaturated alkyl group which may be substituted, an unsaturated cycloalkyl group which may be substituted with a substituent, an aromatic group which may be substituted with a substituent, or a heterocyclic group which may be substituted with a substituent , An alkoxy group that may be substituted with a substituent, an unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, and a non-optionally substituted substituent. Selected from saturated thioalkoxy groups, OH, SH, CN, SCN, OCN.
R m , R n , R o , and R p may combine with R 7 or R 8 to form a ring. )
R 9 X 9 Y General formula (5)
(R 9 is a C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h.
n, a, b, c, d, e, f, g, and h are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e + f + g + h.
X 9 is, SO 2, C = O, C = S, R q P = O, R r P = S, S = O, is selected from Si = O.
R q and R r are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a group that may be substituted with a substituent. A saturated alkyl group, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, a heterocyclic group that may be substituted with a substituent, and a substituent An alkoxy group which may be substituted, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, OH , SH, CN, SCN, and OCN.
R q and R r may combine with R 9 to form a ring.
Y is selected from O and S. )
(R 10 X 10 ) (R 11 X 11 ) (R 12 X 12 ) C General formula (6)
(R 10 , R 11 , and R 12 are each independently C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h .
n, a, b, c, d, e, f, g, and h are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e + f + g + h.
Any two of R 10 , R 11 , and R 12 may combine to form a ring, in which case the group forming the ring satisfies 2n = a + b + c + d + e + f + g + h. Three of R 10 , R 11 , and R 12 may combine to form a ring, in which case two of the three satisfy 2n = a + b + c + d + e + f + g + h, and one group satisfies 2n−1 = a + b + c + d + e + f + g + h. Fulfill.
X 10 is, SO 2, C = O, C = S, R s P = O, R t P = S, S = O, is selected from Si = O.
X 11 is, SO 2, C = O, C = S, R u P = O, R v P = S, S = O, is selected from Si = O.
X 12 is, SO 2, C = O, C = S, R w P = O, R x P = S, S = O, is selected from Si = O.
R s , R t , R u , R v , R w , and R x are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, or a cycloalkyl that may be substituted with a substituent. Group, an unsaturated alkyl group that may be substituted with a substituent, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, or a substituent that is substituted with a substituent A heterocyclic group which may be substituted, an alkoxy group which may be substituted with a substituent, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, and a substituent It is selected from an unsaturated thioalkoxy group which may be substituted, OH, SH, CN, SCN, OCN.
R s , R t , R u , R v , R w , and R x may combine with R 10 , R 11, or R 12 to form a ring. )
The meaning of the phrase “may be substituted with a substituent” in the chemical structures represented by the general formulas (4) to (6) has been explained in the general formulas (1) to (3). Is synonymous with
In the chemical structures represented by the general formulas (4) to (6), n is preferably an integer of 0 to 6, more preferably an integer of 0 to 4, and particularly preferably an integer of 0 to 2. In the chemical structures represented by the above general formulas (4) to (6), when R 7 and R 8 are bonded, or R 10 , R 11 , and R 12 are bonded to form a ring. In the formula, n is preferably an integer of 1 to 8, more preferably an integer of 1 to 7, and particularly preferably an integer of 1 to 3.
　塩のアニオンの化学構造は、下記一般式（７）、一般式（８）又は一般式（９）で表されるものがさらに好ましい。
（Ｒ１３ＳＯ２）（Ｒ１４ＳＯ２）Ｎ　　　　　　　　　一般式（７）
　（Ｒ１３、Ｒ１４は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅである。
　ｎ、ａ、ｂ、ｃ、ｄ、ｅはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。
　また、Ｒ１３とＲ１４は、互いに結合して環を形成しても良く、その場合は、２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。）
　Ｒ１５ＳＯ３　　　　　　　　　　　　一般式（８）
　（Ｒ１５は、ＣｎＨａＦｂＣｌｃＢｒｄＩｅである。
　ｎ、ａ、ｂ、ｃ、ｄ、ｅはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。）
（Ｒ１６ＳＯ２）（Ｒ１７ＳＯ２）（Ｒ１８ＳＯ２）Ｃ　　　　　　　一般式（９）
　（Ｒ１６、Ｒ１７、Ｒ１８は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅである。
　ｎ、ａ、ｂ、ｃ、ｄ、ｅはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。
　Ｒ１６、Ｒ１７、Ｒ１８のうちいずれか２つが結合して環を形成しても良く、その場合、環を形成する基は２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。また、Ｒ１６、Ｒ１７、Ｒ１８の３つが結合して環を形成しても良く、その場合、３つのうち２つの基が２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たし、１つの基が２ｎ－１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。） As for the chemical structure of the anion of a salt, what is represented by following General formula (7), General formula (8) or General formula (9) is still more preferable.
(R 13 SO 2 ) (R 14 SO 2 ) N General formula (7)
(R 13 and R 14 are each independently C n H a F b Cl c Br d I e .
n, a, b, c, d, and e are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e.
R 13 and R 14 may combine with each other to form a ring, in which case 2n = a + b + c + d + e is satisfied. )
R 15 SO 3 general formula (8)
(R 15 is a C n H a F b Cl c Br d I e.
n, a, b, c, d, and e are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e. )
(R 16 SO 2 ) (R 17 SO 2 ) (R 18 SO 2 ) C General formula (9)
(R 16 , R 17 , and R 18 are each independently C n H a F b Cl c Br d I e .
n, a, b, c, d, and e are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e.
Any two of R 16 , R 17 , and R 18 may combine to form a ring, in which case the group forming the ring satisfies 2n = a + b + c + d + e. Three of R 16 , R 17 and R 18 may combine to form a ring, in which case two groups out of the three satisfy 2n = a + b + c + d + e, and one group satisfies 2n−1 = a + b + c + d + e. Fulfill. )
　上記一般式（７）～（９）で表される化学構造において、ｎは０～６の整数が好ましく、０～４の整数がより好ましく、０～２の整数が特に好ましい。なお、上記一般式（７）～（９）で表される化学構造の、Ｒ１３とＲ１４が結合、又は、Ｒ１６、Ｒ１７、Ｒ１８が結合して環を形成している場合には、ｎは１～８の整数が好ましく、１～７の整数がより好ましく、１～３の整数が特に好ましい。 In the chemical structures represented by the general formulas (7) to (9), n is preferably an integer of 0 to 6, more preferably an integer of 0 to 4, and particularly preferably an integer of 0 to 2. In the chemical structures represented by the above general formulas (7) to (9), when R 13 and R 14 are bonded or R 16 , R 17 , and R 18 are bonded to form a ring. In the formula, n is preferably an integer of 1 to 8, more preferably an integer of 1 to 7, and particularly preferably an integer of 1 to 3.
　また、上記一般式（７）～（９）で表される化学構造において、ａ、ｃ、ｄ、ｅが０のものが好ましい。 In the chemical structures represented by the general formulas (7) to (9), those in which a, c, d, and e are 0 are preferable.
　金属塩は、（ＣＦ３ＳＯ２）２ＮＬｉ（以下、「ＬｉＴＦＳＡ」ということがある。）、（ＦＳＯ２）２ＮＬｉ（以下、「ＬｉＦＳＡ」ということがある。）、（Ｃ２Ｆ５ＳＯ２）２ＮＬｉ、ＦＳＯ２（ＣＦ３ＳＯ２）ＮＬｉ、（ＳＯ２ＣＦ２ＣＦ２ＳＯ２）ＮＬｉ、（ＳＯ２ＣＦ２ＣＦ２ＣＦ２ＳＯ２）ＮＬｉ、ＦＳＯ２（ＣＨ３ＳＯ２）ＮＬｉ、ＦＳＯ２（Ｃ２Ｆ５ＳＯ２）ＮＬｉ、又はＦＳＯ２（Ｃ２Ｈ５ＳＯ２）ＮＬｉが特に好ましい。 The metal salt is (CF 3 SO 2 ) 2 NLi (hereinafter sometimes referred to as “LiTFSA”), (FSO 2 ) 2 NLi (hereinafter sometimes referred to as “LiFSA”), (C 2 F 5 SO 2 ) 2 NLi, FSO 2 (CF 3 SO 2 ) NLi, (SO 2 CF 2 CF 2 SO 2 ) NLi, (SO 2 CF 2 CF 2 CF 2 SO 2 ) NLi, FSO 2 (CH 3 SO 2 ) NLi FSO 2 (C 2 F 5 SO 2 ) NLi or FSO 2 (C 2 H 5 SO 2 ) NLi is particularly preferred.
　本発明の金属塩は、以上で説明したカチオンとアニオンをそれぞれ適切な数で組み合わせたものを採用すれば良い。本発明の電解液における金属塩は１種類を採用しても良いし、複数種を併用しても良い。 The metal salt of the present invention may be a combination of an appropriate number of cations and anions described above. One kind of metal salt in the electrolytic solution of the present invention may be used, or a plurality of kinds may be used in combination.
　ヘテロ元素を有する有機溶媒としては、ヘテロ元素が窒素、酸素、硫黄、ハロゲンから選択される少なくとも１つである有機溶媒が好ましく、ヘテロ元素が窒素又は酸素から選択される少なくとも１つである有機溶媒がより好ましい。また、ヘテロ元素を有する有機溶媒としては、ＮＨ基、ＮＨ２基、ＯＨ基、ＳＨ基などのプロトン供与基を有さない、非プロトン性溶媒が好ましい。 As the organic solvent having a hetero element, an organic solvent in which the hetero element is at least one selected from nitrogen, oxygen, sulfur and halogen is preferable, and an organic solvent in which the hetero element is at least one selected from nitrogen or oxygen Is more preferable. As the organic solvent having a hetero element, an aprotic solvent having no proton donating group such as NH group, NH 2 group, OH group, and SH group is preferable.
　ヘテロ元素を有する有機溶媒（以下、単に「有機溶媒」ということがある。）を具体的に例示すると、アセトニトリル、プロピオニトリル、アクリロニトリル、マロノニトリル等のニトリル類、１，２－ジメトキシエタン、１，２－ジエトキシエタン、テトラヒドロフラン、１，２－ジオキサン、１，３－ジオキサン、１，４－ジオキサン、２，２－ジメチル－１，３－ジオキソラン、２－メチルテトラヒドロピラン、２－メチルテトラヒドロフラン、クラウンエーテル等のエーテル類、エチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート等のカーボネート類、ホルムアミド、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミド、Ｎ－メチルピロリドン等のアミド類、イソプロピルイソシアネート、ｎ－プロピルイソシアネート、クロロメチルイソシアネート等のイソシアネート類、酢酸メチル、酢酸エチル、酢酸プロピル、プロピオン酸メチル、蟻酸メチル、蟻酸エチル、酢酸ビニル、メチルアクリレート、メチルメタクリレート等のエステル類、グリシジルメチルエーテル、エポキシブタン、２－エチルオキシラン等のエポキシ類、オキサゾール、２－エチルオキサゾール、オキサゾリン、２－メチル－２－オキサゾリン等のオキサゾール類、アセトン、メチルエチルケトン、メチルイソブチルケトン等のケトン類、無水酢酸、無水プロピオン酸等の酸無水物、ジメチルスルホン、スルホラン等のスルホン類、ジメチルスルホキシド等のスルホキシド類、１－ニトロプロパン、２－ニトロプロパン等のニトロ類、フラン、フルフラール等のフラン類、γ―ブチロラクトン、γ―バレロラクトン、δ―バレロラクトン等の環状エステル類、チオフェン、ピリジン等の芳香族複素環類、テトラヒドロ－４－ピロン、１－メチルピロリジン、Ｎ－メチルモルフォリン等の複素環類、リン酸トリメチル、リン酸トリエチル等のリン酸エステル類を挙げることができる。 Specific examples of the organic solvent having a hetero element (hereinafter sometimes simply referred to as “organic solvent”) include nitriles such as acetonitrile, propionitrile, acrylonitrile, malononitrile, 1,2-dimethoxyethane, 1, 2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 2,2-dimethyl-1,3-dioxolane, 2-methyltetrahydropyran, 2-methyltetrahydrofuran, crown Ethers such as ether, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolide Amides such as isopropyl isocyanate, n-propyl isocyanate, chloromethyl isocyanate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, methyl formate, ethyl formate, vinyl acetate, methyl acrylate, methyl methacrylate, etc. Esters, glycidyl methyl ether, epoxy butane, epoxy such as 2-ethyloxirane, oxazole, 2-ethyloxazole, oxazoline, oxazole such as 2-methyl-2-oxazoline, ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone Acid anhydrides such as acetic anhydride and propionic anhydride, sulfones such as dimethyl sulfone and sulfolane, sulfoxides such as dimethyl sulfoxide, 1-nitropropane and 2-nitrate Nitros such as propane, furans such as furan and furfural, cyclic esters such as γ-butyrolactone, γ-valerolactone and δ-valerolactone, aromatic heterocycles such as thiophene and pyridine, tetrahydro-4-pyrone, Examples thereof include heterocyclic rings such as 1-methylpyrrolidine and N-methylmorpholine, and phosphate esters such as trimethyl phosphate and triethyl phosphate.
　有機溶媒として、下記一般式（１０）で示される鎖状カーボネートを挙げることができる。
Ｒ１９ＯＣＯＯＲ２０　　　　　　　　　　　　　　　一般式（１０）
（Ｒ１９、Ｒ２０は、それぞれ独立に、鎖状アルキルであるＣｎＨａＦｂＣｌｃＢｒｄＩｅ、又は、環状アルキルを化学構造に含むＣｍＨｆＦｇＣｌｈＢｒｉＩｊのいずれかから選択される。ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｍ、ｆ、ｇ、ｈ、ｉ、ｊはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ、２ｍ＝ｆ＋ｇ＋ｈ＋ｉ＋ｊを満たす。） Examples of the organic solvent include chain carbonates represented by the following general formula (10).
R 19 OCOOR 20 general formula (10)
(R 19 and R 20 each independently represent C n H a F b Cl c Br d I e which is a chain alkyl, or C m H f F g Cl h Br i I containing a cyclic alkyl in the chemical structure. .n selected from any of j, a, b, c, d, e, m, f, g, h, i, j are each independently an integer of 0 or more, 2n + 1 = a + b + c + d + e, 2m = f + g + h + i + j Meet)
　上記一般式（１０）で表される鎖状カーボネートにおいて、ｎは１～６の整数が好ましく、１～４の整数がより好ましく、１～２の整数が特に好ましい。ｍは３～８の整数が好ましく、４～７の整数がより好ましく、５～６の整数が特に好ましい。また、上記一般式（１０）で表される鎖状カーボネートのうち、ジメチルカーボネート（以下、「ＤＭＣ」ということがある。）、ジエチルカーボネート（以下、「ＤＥＣ」ということがある。）、エチルメチルカーボネート（以下、「ＥＭＣ」ということがある。）が特に好ましい。 In the chain carbonate represented by the general formula (10), n is preferably an integer of 1 to 6, more preferably an integer of 1 to 4, and particularly preferably an integer of 1 to 2. m is preferably an integer of 3 to 8, more preferably an integer of 4 to 7, and particularly preferably an integer of 5 to 6. Among the chain carbonates represented by the general formula (10), dimethyl carbonate (hereinafter sometimes referred to as “DMC”), diethyl carbonate (hereinafter sometimes referred to as “DEC”), ethylmethyl Carbonate (hereinafter sometimes referred to as “EMC”) is particularly preferred.
　有機溶媒としては、比誘電率が２０以上又はドナー性のエーテル酸素を有する溶媒が好ましく、そのような有機溶媒として、アセトニトリル、プロピオニトリル、アクリロニトリル、マロノニトリル等のニトリル類、１，２－ジメトキシエタン、１，２－ジエトキシエタン、テトラヒドロフラン、１，２－ジオキサン、１，３－ジオキサン、１，４－ジオキサン、２，２－ジメチル－１，３－ジオキソラン、２－メチルテトラヒドロピラン、２－メチルテトラヒドロフラン、クラウンエーテル等のエーテル類、Ｎ，Ｎ－ジメチルホルムアミド、アセトン、ジメチルスルホキシド、スルホランを挙げることができ、特に、アセトニトリル（以下、「ＡＮ」ということがある。）、１，２－ジメトキシエタン（以下、「ＤＭＥ」ということがある。）が好ましい。
　これらの有機溶媒は単独で電解液に用いても良いし、複数を併用しても良い。 As the organic solvent, a solvent having a relative dielectric constant of 20 or more or a donor ether oxygen is preferable. Examples of such an organic solvent include nitriles such as acetonitrile, propionitrile, acrylonitrile, and malononitrile, and 1,2-dimethoxyethane. 1,2-diethoxyethane, tetrahydrofuran, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 2,2-dimethyl-1,3-dioxolane, 2-methyltetrahydropyran, 2-methyl Mention may be made of ethers such as tetrahydrofuran and crown ether, N, N-dimethylformamide, acetone, dimethyl sulfoxide and sulfolane, and in particular acetonitrile (hereinafter sometimes referred to as “AN”), 1,2-dimethoxyethane. (Hereafter referred to as “DME”) ) Is preferable.
These organic solvents may be used alone in the electrolytic solution, or a plurality of them may be used in combination.
　本発明の電解液は、その振動分光スペクトルにおいて、電解液に含まれる有機溶媒由来のピーク強度につき、有機溶媒本来のピークの強度をＩｏとし、有機溶媒本来のピークがシフトしたピーク（以下、「シフトピーク」ということがある。）の強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする。すなわち、本発明の電解液を振動分光測定に供し得られる振動分光スペクトルチャートにおいて、上記２つのピーク強度の関係はＩｓ＞Ｉｏとなる。 In the vibrational spectroscopic spectrum of the electrolyte solution of the present invention, the peak intensity derived from the organic solvent contained in the electrolyte solution is denoted by Io, and the peak of the organic solvent inherent peak is shifted (hereinafter, “ If the intensity of “shift peak” is sometimes referred to as “Is”, Is> Io. That is, in the vibrational spectral spectrum chart obtained by subjecting the electrolytic solution of the present invention to vibrational spectral measurement, the relationship between the two peak intensities is Is> Io.
　ここで、「有機溶媒本来のピーク」とは、有機溶媒のみを振動分光測定した場合のピーク位置（波数）に、観察されるピークを意味する。有機溶媒本来のピークの強度Ｉｏの値と、シフトピークの強度Ｉｓの値は、振動分光スペクトルにおける各ピークのベースラインからの高さ又は面積である。 Here, “the original peak of the organic solvent” means a peak observed at the peak position (wave number) when vibration spectroscopy measurement is performed only on the organic solvent. The value of the peak intensity Io inherent in the organic solvent and the value of the shift peak intensity Is are the height or area from the baseline of each peak in the vibrational spectrum.
　本発明の電解液の振動分光スペクトルにおいて、有機溶媒本来のピークがシフトしたピークが複数存在する場合には、最もＩｓとＩｏの関係を判断しやすいピークに基づいて当該関係を判断すればよい。また、本発明の電解液にヘテロ元素を有する有機溶媒を複数種用いた場合には、最もＩｓとＩｏの関係を判断しやすい（最もＩｓとＩｏの差が顕著な）有機溶媒を選択し、そのピーク強度に基づいてＩｓとＩｏの関係を判断すればよい。また、ピークのシフト量が小さく、シフト前後のピークが重なってなだらかな山のように見える場合は、既知の手段を用いてピーク分離を行い、ＩｓとＩｏの関係を判断してもよい。 In the vibrational spectroscopic spectrum of the electrolytic solution of the present invention, when there are a plurality of peaks in which the original peak of the organic solvent is shifted, the relationship may be determined based on the peak from which the relationship between Is and Io is most easily determined. In addition, when a plurality of organic solvents having heteroelements are used in the electrolytic solution of the present invention, an organic solvent that can determine the relationship between Is and Io most easily (the difference between Is and Io is most pronounced) is selected, The relationship between Is and Io may be determined based on the peak intensity. If the peak shift amount is small and the peaks before and after the shift appear to be a gentle mountain, peak separation may be performed using known means to determine the relationship between Is and Io.
　なお、ヘテロ元素を有する有機溶媒を複数種用いた電解液の振動分光スペクトルにおいては、カチオンと最も配位し易い有機溶媒（以下、「優先配位溶媒」ということがある。）のピークが他に優先してシフトする。ヘテロ元素を有する有機溶媒を複数種用いた電解液において、ヘテロ元素を有する有機溶媒全体に対する優先配位溶媒の質量％は、４０％以上が好ましく、５０％以上がより好ましく、６０％以上がさらに好ましく、８０％以上が特に好ましい。また、ヘテロ元素を有する有機溶媒を複数種用いた電解液において、ヘテロ元素を有する有機溶媒全体に対する優先配位溶媒の体積％は、４０％以上が好ましく、５０％以上がより好ましく、６０％以上がさらに好ましく、８０％以上が特に好ましい。 Note that in the vibrational spectroscopic spectrum of an electrolytic solution using a plurality of organic solvents having a hetero element, the peak of an organic solvent that is most easily coordinated with a cation (hereinafter sometimes referred to as “preferred coordination solvent”) is another. Shift in preference to. In an electrolytic solution using a plurality of organic solvents having a hetero element, the mass% of the preferential coordination solvent with respect to the entire organic solvent having a hetero element is preferably 40% or more, more preferably 50% or more, and further preferably 60% or more. 80% or more is particularly preferable. Further, in the electrolytic solution using a plurality of organic solvents having a hetero element, the volume% of the preferential coordination solvent with respect to the entire organic solvent having a hetero element is preferably 40% or more, more preferably 50% or more, and 60% or more. Is more preferable, and 80% or more is particularly preferable.
　本発明の電解液の振動分光スペクトルにおける上記２つのピーク強度の関係は、Ｉｓ＞２×Ｉｏの条件を満たすことが好ましく、Ｉｓ＞３×Ｉｏの条件を満たすことがより好ましく、Ｉｓ＞５×Ｉｏの条件を満たすことがさらに好ましく、Ｉｓ＞７×Ｉｏの条件を満たすことが特に好ましい。最も好ましいのは、本発明の電解液の振動分光スペクトルにおいて、有機溶媒本来のピークの強度Ｉｏが観察されず、シフトピークの強度Ｉｓが観察される電解液である。当該電解液においては、電解液に含まれる有機溶媒の分子すべてが金属塩と完全に溶媒和していることを意味する。本発明の電解液は、電解液に含まれる有機溶媒の分子すべてが金属塩と完全に溶媒和している状態（Ｉｏ＝０の状態）が最も好ましい。 The relationship between the two peak intensities in the vibrational spectrum of the electrolytic solution of the present invention preferably satisfies the condition of Is> 2 × Io, more preferably satisfies the condition of Is> 3 × Io, and Is> 5 × It is more preferable that the condition of Io is satisfied, and it is particularly preferable that the condition of Is> 7 × Io is satisfied. Most preferred is an electrolytic solution in which the intensity Io of the peak inherent in the organic solvent is not observed and the intensity Is of the shift peak is observed in the vibrational spectrum of the electrolytic solution of the present invention. In the electrolytic solution, it means that all the molecules of the organic solvent contained in the electrolytic solution are completely solvated with the metal salt. The electrolyte solution of the present invention is most preferably in a state where all the molecules of the organic solvent contained in the electrolyte solution are completely solvated with the metal salt (Io = 0 state).
　本発明の電解液においては、金属塩と、ヘテロ元素を有する有機溶媒（又は優先配位溶媒）が、相互作用を及ぼしていると推定される。具体的には、金属塩と、ヘテロ元素を有する有機溶媒（又は優先配位溶媒）のヘテロ元素とが、配位結合を形成し、金属塩とヘテロ元素を有する有機溶媒（又は優先配位溶媒）からなる安定なクラスターを形成していると推定される。このクラスターは、後述する評価例の結果からみて、概ね、金属塩１分子に対し、ヘテロ元素を有する有機溶媒（又は優先配位溶媒）２分子が配位することにより形成されていると推定される。この点を考慮すると、本発明の電解液における、金属塩１モルに対するヘテロ元素を有する有機溶媒（又は優先配位溶媒）のモル範囲は、１．４モル以上３．５モル未満が好ましく、１．５モル以上３．１モル以下がより好ましく、１．６モル以上３モル以下がさらに好ましい。 In the electrolytic solution of the present invention, it is presumed that the metal salt and the organic solvent (or preferential coordination solvent) having a hetero element have an interaction. Specifically, a metal salt and a hetero element of an organic solvent (or preferential coordination solvent) having a hetero element form a coordination bond, and the organic salt (or preferential coordinating solvent) having a metal salt and a hetero element ) Is estimated to form a stable cluster. From the results of evaluation examples described later, this cluster is presumed to be formed by coordination of two molecules of an organic solvent (or preferential coordination solvent) having a hetero element to one molecule of a metal salt. The Considering this point, the molar range of the organic solvent having a hetero element (or preferential coordination solvent) with respect to 1 mol of the metal salt in the electrolytic solution of the present invention is preferably 1.4 mol or more and less than 3.5 mol. More preferably, it is 0.5 mol or more and 3.1 mol or less, and 1.6 mol or more and 3 mol or less are still more preferable.
　本発明の電解液においては、概ね、金属塩１分子に対し、ヘテロ元素を有する有機溶媒（又は優先配位溶媒）２分子が配位することによりクラスター形成されていると推定されるため、本発明の電解液の濃度（ｍｏｌ／Ｌ）は、金属塩及び有機溶媒それぞれの分子量と、溶液にした場合の密度に依存する。そのため、本発明の電解液の濃度を一概に規定することは適当でない。 In the electrolytic solution of the present invention, it is presumed that clusters are generally formed by coordination of two molecules of an organic solvent (or preferential coordination solvent) having a hetero element to one molecule of a metal salt. The concentration (mol / L) of the electrolytic solution of the invention depends on the molecular weight of each of the metal salt and the organic solvent and the density when the solution is used. Therefore, it is not appropriate to prescribe the concentration of the electrolytic solution of the present invention.
　本発明の電解液の濃度ｃ（ｍｏｌ／Ｌ）を表１に個別に例示する。
Figure JPOXMLDOC01-appb-T000001
 The concentration c (mol / L) of the electrolytic solution of the present invention is individually exemplified in Table 1.
Figure JPOXMLDOC01-appb-T000001
　クラスターを形成している有機溶媒と、クラスターの形成に関与していない有機溶媒とは、それぞれの存在環境が異なる。そのため、振動分光測定において、クラスターを形成している有機溶媒由来のピークは、クラスターの形成に関与していない有機溶媒由来のピーク（有機溶媒本来のピーク）の観察される波数から、高波数側又は低波数側にシフトして観察される。すなわち、シフトピークは、クラスターを形成している有機溶媒のピークに相当する。 The organic solvent that forms the cluster and the organic solvent that is not involved in the formation of the cluster have different environments. Therefore, in vibrational spectroscopy measurement, the peak derived from the organic solvent forming the cluster is higher than the observed wave number of the peak derived from the organic solvent not involved in the cluster formation (original peak of the organic solvent). Or it is observed shifted to the low wavenumber side. That is, the shift peak corresponds to the peak of the organic solvent forming the cluster.
　振動分光スペクトルとしては、ＩＲスペクトル又はラマンスペクトルを挙げることができる。ＩＲ測定の測定方法としては、ヌジョール法、液膜法などの透過測定方法、ＡＴＲ法などの反射測定方法を挙げることができる。ＩＲスペクトル又はラマンスペクトルのいずれを選択するかについては、本発明の電解液の振動分光スペクトルにおいて、ＩｓとＩｏの関係を判断しやすいスペクトルの方を選択すれば良い。なお、振動分光測定は、大気中の水分の影響を軽減又は無視できる条件で行うのがよい。例えば、ドライルーム、グローブボックスなどの低湿度又は無湿度条件下でＩＲ測定を行うこと、又は、電解液を密閉容器に入れたままの状態でラマン測定を行うのがよい。 Examples of the vibrational spectrum include an IR spectrum and a Raman spectrum. Examples of the measurement method for IR measurement include transmission measurement methods such as Nujol method and liquid film method, and reflection measurement methods such as ATR method. As to whether to select an IR spectrum or a Raman spectrum, a spectrum in which the relationship between Is and Io can be easily determined in the vibrational spectrum of the electrolytic solution of the present invention may be selected. The vibrational spectroscopic measurement is preferably performed under conditions that can reduce or ignore the influence of moisture in the atmosphere. For example, IR measurement may be performed under low humidity or no humidity conditions such as a dry room or a glove box, or Raman measurement may be performed with the electrolyte solution in a sealed container.
　ここで、金属塩としてＬｉＴＦＳＡ、有機溶媒としてアセトニトリルを含む本発明の電解液におけるピークにつき、具体的に説明する。 Here, the peak in the electrolytic solution of the present invention containing LiTFSA as the metal salt and acetonitrile as the organic solvent will be specifically described.
　アセトニトリルのみをＩＲ測定した場合、Ｃ及びＮ間の三重結合の伸縮振動に由来するピークが通常２１００～２４００ｃｍ－１付近に観察される。 When only acetonitrile is measured by IR, a peak derived from the stretching vibration of the triple bond between C and N is usually observed in the vicinity of 2100 to 2400 cm −1 .
　ここで、従来の技術常識に従い、アセトニトリル溶媒に対しＬｉＴＦＳＡを１ｍｏｌ／Ｌの濃度で溶解して電解液とした場合を想定する。アセトニトリル１Ｌは約１９ｍｏｌに該当するので、従来の電解液１Ｌには、１ｍｏｌのＬｉＴＦＳＡと１９ｍｏｌのアセトニトリルが存在する。そうすると、従来の電解液においては、ＬｉＴＦＳＡと溶媒和している（Ｌｉに配位している）アセトニトリルと同時に、ＬｉＴＦＳＡと溶媒和していない（Ｌｉに配位していない）アセトニトリルが多数存在する。さて、ＬｉＴＦＳＡと溶媒和しているアセトニトリル分子と、ＬｉＴＦＳＡと溶媒和していないアセトニトリル分子とは、アセトニトリル分子の置かれている環境が異なるので、ＩＲスペクトルにおいては、両者のアセトニトリルピークが区別して観察される。より具体的には、ＬｉＴＦＳＡと溶媒和していないアセトニトリルのピークは、アセトニトリルのみをＩＲ測定した場合と同様の位置（波数）に観察されるが、他方、ＬｉＴＦＳＡと溶媒和しているアセトニトリルのピークは、ピーク位置（波数）が高波数側にシフトして観察される。 Here, it is assumed that LiTFSA is dissolved in an acetonitrile solvent at a concentration of 1 mol / L to obtain an electrolytic solution according to conventional technical common sense. Since 1 L of acetonitrile corresponds to about 19 mol, 1 L of conventional electrolyte includes 1 mol of LiTFSA and 19 mol of acetonitrile. Then, in the conventional electrolyte, there are many acetonitriles that are not solvated with LiTFSA (not coordinated with Li) simultaneously with acetonitrile that is solvated with LiTFSA (coordinated with Li). . Now, since the acetonitrile molecule is different between the LiTFSA solvated acetonitrile molecule and the LiTFSA non-solvated acetonitrile molecule, in the IR spectrum, the acetonitrile peaks of both are distinguished and observed. Is done. More specifically, the peak of acetonitrile that is not solvated with LiTFSA is observed at the same position (wave number) as in the case of IR measurement of only acetonitrile, but the peak of acetonitrile that is solvated with LiTFSA. Is observed with the peak position (wave number) shifted to the high wave number side.
　そして、従来の電解液の濃度においては、ＬｉＴＦＳＡと溶媒和していないアセトニトリルが多数存在するのであるから、従来の電解液の振動分光スペクトルにおいて、アセトニトリル本来のピークの強度Ｉｏと、アセトニトリル本来のピークがシフトしたピークの強度Ｉｓとの関係は、Ｉｓ＜Ｉｏとなる。 Since there are many acetonitriles that are not solvated with LiTFSA in the concentration of the conventional electrolyte, in the vibrational spectrum of the conventional electrolyte, the peak intensity Io of the original acetonitrile and the peak of the original acetonitrile The relationship with the intensity Is of the peak shifted is Is <Io.
　他方、本発明の電解液は従来の電解液と比較してＬｉＴＦＳＡの濃度が高く、かつ、電解液においてＬｉＴＦＳＡと溶媒和している（クラスターを形成している）アセトニトリル分子の数が、ＬｉＴＦＳＡと溶媒和していないアセトニトリル分子の数よりも多い。そうすると、本発明の電解液の振動分光スペクトルにおける、アセトニトリル本来のピークの強度Ｉｏと、アセトニトリル本来のピークがシフトしたピークの強度Ｉｓとの関係は、Ｉｓ＞Ｉｏとなる。 On the other hand, the electrolytic solution of the present invention has a higher LiTFSA concentration than the conventional electrolytic solution, and the number of acetonitrile molecules solvated with LiTFSA (forming clusters) in the electrolytic solution is different from that of LiTFSA. More than the number of unsolvated acetonitrile molecules. Then, the relation between the intensity Io of the original peak of the acetonitrile and the intensity Is of the peak obtained by shifting the original peak of acetonitrile in the vibrational spectrum of the electrolytic solution of the present invention is Is> Io.
　表２に、本発明の電解液の振動分光スペクトルにおいて、Ｉｏ及びＩｓの算出に有用と考えられる有機溶媒の波数と、その帰属を例示する。なお、振動分光スペクトルの測定装置、測定環境、測定条件に因って、観察されるピークの波数が以下の波数と異なる場合があることを付け加えておく。 Table 2 exemplifies wave numbers of organic solvents that are considered useful for the calculation of Io and Is in the vibrational spectrum of the electrolytic solution of the present invention, and their attribution. It should be added that the wave number of the observed peak may be different from the following wave numbers depending on the measurement apparatus, measurement environment, and measurement conditions of the vibrational spectrum.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　有機溶媒の波数とその帰属につき、公知のデータを参考としてもよい。参考文献として、日本分光学会測定法シリーズ１７　ラマン分光法、濱口宏夫、平川暁子、学会出版センター、２３１～２４９頁を挙げる。また、コンピュータを用いた計算でも、Ｉｏ及びＩｓの算出に有用と考えられる有機溶媒の波数と、有機溶媒と金属塩が配位した場合の波数シフトを予測することができる。例えば、Ｇａｕｓｓｉａｎ０９（登録商標、ガウシアン社）を用い、密度汎関数をＢ３ＬＹＰ、基底関数を６－３１１Ｇ＋＋（ｄ，ｐ）として計算すればよい。当業者は、表２の記載、公知のデータ、コンピュータでの計算結果を参考にして、有機溶媒のピークを選定し、Ｉｏ及びＩｓを算出することができる。 公 知 Known data on the wave number of organic solvents and their attribution may be used as a reference. As references, the Spectroscopical Society of Japan Measurement Series 17, Raman Spectroscopy, Hiroo Higuchi, Atsuko Hirakawa, Academic Publishing Center, pages 231 to 249 are listed. In addition, the calculation using a computer can also predict the wave number of an organic solvent that is considered useful for the calculation of Io and Is and the wave number shift when the organic solvent and the metal salt are coordinated. For example, Gaussian 09 (registered trademark, Gaussian) may be used, and the density functional may be calculated as B3LYP and the basis function as 6-311G ++ (d, p). A person skilled in the art can calculate the Io and Is by selecting the peak of the organic solvent with reference to the description in Table 2, known data, and the calculation result in the computer.
　本発明の電解液は、従来の電解液と比較して、金属塩と有機溶媒の存在環境が異なり、かつ、金属塩濃度が高いため、電解液中の金属イオン輸送速度の向上（特に、金属がリチウムの場合、リチウム輸率の向上）、電極と電解液界面の反応速度の向上、電池のハイレート充放電時に起こる電解液の塩濃度の偏在の緩和、電気二重層容量の増大などが期待できる。さらに、本発明の電解液においては、ヘテロ元素を有する有機溶媒の大半が金属塩とクラスターを形成していることから、電解液に含まれる有機溶媒の蒸気圧が低くなる。その結果として、本発明の電解液からの有機溶媒の揮発が低減できる。 The electrolytic solution of the present invention is different from the conventional electrolytic solution in that the presence environment of the metal salt and the organic solvent is different and the concentration of the metal salt is high, so that the metal ion transport rate in the electrolytic solution is improved (especially metal When Li is lithium, the lithium transport number is improved), the reaction rate between the electrode and the electrolyte solution is improved, the uneven distribution of the salt concentration of the electrolyte solution that occurs during high-rate charge / discharge of the battery, and the electric double layer capacity can be expected to increase . Furthermore, in the electrolytic solution of the present invention, since most of the organic solvent having a hetero element forms a cluster with a metal salt, the vapor pressure of the organic solvent contained in the electrolytic solution is lowered. As a result, volatilization of the organic solvent from the electrolytic solution of the present invention can be reduced.
　本発明の電解液は、従来の電池の電解液と比較して、粘度が高い。そのため、本発明の電解液を用いた電池であれば、仮に電池が破損したとしても、電解液漏れが抑制される。また、従来の電解液を用いたリチウムイオン二次電池は、高速充放電サイクル時に容量減少が顕著であった。その理由の一つとして、急速に充放電を繰り返した際の電解液中に生じたＬｉ濃度ムラに因り、電極との反応界面に十分な量のＬｉを電解液が供給できなくなったこと、つまり、電解液のＬｉ濃度の偏在が考えられる。しかしながら、本発明の電解液を用いた二次電池は、高速充放電時に容量が好適に維持されることが明らかになった。本発明の電解液の高粘度との物性により、電解液のＬｉ濃度の偏在を抑制できたことが理由と考えられる。また、本発明の電解液の高粘度との物性により、電極界面における電解液の保液性が向上し、電極界面で電解液が不足する状態（いわゆる液枯れ状態）を抑制することも、高速充放電サイクル時の容量低下が抑制された一因と考えられる。 The electrolyte of the present invention has a higher viscosity than the conventional battery electrolyte. Therefore, if it is a battery using the electrolyte solution of this invention, even if a battery is damaged, electrolyte solution leakage is suppressed. Moreover, the capacity | capacitance reduction of the lithium ion secondary battery using the conventional electrolyte solution was remarkable at the time of a high-speed charging / discharging cycle. One reason for this is that due to the uneven Li concentration generated in the electrolyte when rapidly charging and discharging, the electrolyte cannot supply a sufficient amount of Li to the reaction interface with the electrode. The uneven distribution of Li concentration in the electrolytic solution can be considered. However, it has become clear that the capacity of the secondary battery using the electrolytic solution of the present invention is suitably maintained during high-speed charge / discharge. It is considered that the uneven distribution of Li concentration in the electrolytic solution could be suppressed due to the physical properties of the electrolytic solution of the present invention with high viscosity. In addition, due to the high viscosity of the electrolyte solution of the present invention, the liquid retention of the electrolyte solution at the electrode interface is improved, and the state where the electrolyte solution is insufficient at the electrode interface (so-called liquid withdrawn state) can also be suppressed. This is considered to be one of the reasons that the capacity decrease during the charge / discharge cycle is suppressed.
　本発明の電解液の粘度η（ｍＰａ・ｓ）について述べると、１０＜η＜５００の範囲が好ましく、１２＜η＜４００の範囲がより好ましく、１５＜η＜３００の範囲がさらに好ましく、１８＜η＜１５０の範囲が特に好ましく、２０＜η＜１４０の範囲が最も好ましい。 Regarding the viscosity η (mPa · s) of the electrolytic solution of the present invention, a range of 10 <η <500 is preferable, a range of 12 <η <400 is more preferable, a range of 15 <η <300 is further preferable, and 18 A range of <η <150 is particularly preferable, and a range of 20 <η <140 is most preferable.
　電解液のイオン伝導度σ（ｍＳ／ｃｍ）は高ければ高いほど、電解液中でイオンが移動し易い。このため、このような電解液は優れた電池の電解液となり得る。本発明の電解液のイオン伝導度σ（ｍＳ／ｃｍ）について述べると、１≦σであるのが好ましい。本発明の電解液のイオン伝導度σ（ｍＳ／ｃｍ）につき、あえて、上限を含めた好適な範囲を示すと、２＜σ＜２００の範囲が好ましく、３＜σ＜１００の範囲がより好ましく、４＜σ＜５０の範囲がさらに好ましく、５＜σ＜３５の範囲が特に好ましい。 The higher the ionic conductivity σ (mS / cm) of the electrolytic solution, the easier it is for ions to move in the electrolytic solution. For this reason, such an electrolyte can be an excellent battery electrolyte. The ion conductivity σ (mS / cm) of the electrolytic solution of the present invention is preferably 1 ≦ σ. Regarding the ionic conductivity σ (mS / cm) of the electrolytic solution of the present invention, when a suitable range including the upper limit is shown, a range of 2 <σ <200 is preferable, and a range of 3 <σ <100 is more preferable. The range of 4 <σ <50 is more preferable, and the range of 5 <σ <35 is particularly preferable.
　ところで、本発明の電解液は金属塩のカチオンを高濃度で含有する。このため、本発明の電解液中において、隣り合うカチオン間の距離は極めて近い。そして、二次電池の充放電時にリチウムイオン等のカチオンが正極と負極との間を移動する際には、移動先の電極に直近のカチオンが先ず当該電極に供給される。そして、供給された当該カチオンがあった場所には、当該カチオンに隣り合う他のカチオンが移動する。つまり、本発明の電解液中においては、隣り合うカチオンが供給対象となる電極に向けて順番に一つずつ位置を変えるという、ドミノ倒し様の現象が生じていると予想される。このため、充放電時のカチオンの移動距離は短く、その分だけカチオンの移動速度が高いと考えられる。そして、このことに起因して、本発明の電解液を有する二次電池の反応速度は高いと考えられる。 Incidentally, the electrolytic solution of the present invention contains a metal salt cation in a high concentration. For this reason, in the electrolytic solution of the present invention, the distance between adjacent cations is extremely short. When a cation such as lithium ion moves between the positive electrode and the negative electrode during charge / discharge of the secondary battery, the cation closest to the destination electrode is first supplied to the electrode. And the other cation adjacent to the said cation moves to the place with the said supplied cation. In other words, in the electrolytic solution of the present invention, it is expected that a domino-like phenomenon occurs in which adjacent cations change one by one toward the electrode to be supplied one by one. For this reason, the movement distance of the cation at the time of charging / discharging is short, and it is thought that the movement speed | rate of a cation is high by that much. And it originates in this and it is thought that the reaction rate of the secondary battery which has the electrolyte solution of this invention is high.
　本発明の電解液における密度ｄ（ｇ／ｃｍ３）は、好ましくはｄ≧１．２又はｄ≦２．２であり、１．２≦ｄ≦２．２の範囲内がより好ましく、１．２４≦ｄ≦２．０の範囲内がより好ましく、１．２６≦ｄ≦１．８の範囲内がさらに好ましく、１．２７≦ｄ≦１．６の範囲内が特に好ましい。なお、本発明の電解液における密度ｄ（ｇ／ｃｍ３）は、２０℃での密度を意味する。 The density d (g / cm 3 ) in the electrolytic solution of the present invention is preferably d ≧ 1.2 or d ≦ 2.2, more preferably 1.2 ≦ d ≦ 2.2. A range of 24 ≦ d ≦ 2.0 is more preferable, a range of 1.26 ≦ d ≦ 1.8 is more preferable, and a range of 1.27 ≦ d ≦ 1.6 is particularly preferable. The density d (g / cm 3 ) in the electrolytic solution of the present invention means the density at 20 ° C.
　本発明の電解液における電解液の密度ｄ（ｇ／ｃｍ３）を電解液の濃度ｃ（ｍｏｌ／Ｌ）で除したｄ／ｃは、０．１５≦ｄ／ｃ≦０．７１の範囲内が好ましく、０．１５≦ｄ／ｃ≦０．５６の範囲内が好ましく、０．２５≦ｄ／ｃ≦０．５６の範囲内がより好ましく、０．２６≦ｄ／ｃ≦０．５０の範囲内がさらに好ましく、０．２７≦ｄ／ｃ≦０．４７の範囲内が特に好ましい。 D / c obtained by dividing the density d (g / cm 3 ) of the electrolytic solution in the electrolytic solution of the present invention by the concentration c (mol / L) of the electrolytic solution is in the range of 0.15 ≦ d / c ≦ 0.71. In the range of 0.15 ≦ d / c ≦ 0.56, more preferably in the range of 0.25 ≦ d / c ≦ 0.56, and 0.26 ≦ d / c ≦ 0.50. Within the range is more preferable, and within the range of 0.27 ≦ d / c ≦ 0.47 is particularly preferable.
　本発明の電解液におけるｄ／ｃは、金属塩と有機溶媒を特定した場合でも規定することができる。例えば、金属塩としてＬｉＴＦＳＡ、有機溶媒としてＤＭＥを選択した場合には、ｄ／ｃは０．４２≦ｄ／ｃ≦０．５６の範囲内が好ましく、０．４４≦ｄ／ｃ≦０．５２の範囲内がより好ましい。金属塩としてＬｉＴＦＳＡ、有機溶媒としてＡＮを選択した場合には、ｄ／ｃは０．３５≦ｄ／ｃ≦０．４１の範囲内が好ましく、０．３６≦ｄ／ｃ≦０．３９の範囲内がより好ましい。金属塩としてＬｉＦＳＡ、有機溶媒としてＤＭＥを選択した場合には、ｄ／ｃは０．３２≦ｄ／ｃ≦０．４６の範囲内が好ましく、０．３４≦ｄ／ｃ≦０．４２の範囲内がより好ましい。金属塩としてＬｉＦＳＡ、有機溶媒としてＡＮを選択した場合には、ｄ／ｃは０．２５≦ｄ／ｃ≦０．３１の範囲内が好ましく、０．２６≦ｄ／ｃ≦０．２９の範囲内がより好ましい。金属塩としてＬｉＦＳＡ、有機溶媒としてＤＭＣを選択した場合には、ｄ／ｃは０．３２≦ｄ／ｃ≦０．４８の範囲内が好ましく、０．３２≦ｄ／ｃ≦０．４６の範囲内が好ましく、０．３４≦ｄ／ｃ≦０．４２の範囲内がより好ましい。金属塩としてＬｉＦＳＡ、有機溶媒としてＥＭＣを選択した場合には、ｄ／ｃは０．３４≦ｄ／ｃ≦０．５０の範囲内が好ましく、０．３７≦ｄ／ｃ≦０．４５の範囲内がより好ましい。金属塩としてＬｉＦＳＡ、有機溶媒としてＤＥＣを選択した場合には、ｄ／ｃは０．３６≦ｄ／ｃ≦０．５４の範囲内が好ましく、０．３９≦ｄ／ｃ≦０．４８の範囲内がより好ましい。 D / c in the electrolytic solution of the present invention can be defined even when a metal salt and an organic solvent are specified. For example, when LiTFSA is selected as the metal salt and DME is selected as the organic solvent, d / c is preferably within the range of 0.42 ≦ d / c ≦ 0.56, and 0.44 ≦ d / c ≦ 0.52 The range of is more preferable. When LiTFSA is selected as the metal salt and AN is selected as the organic solvent, d / c is preferably in the range of 0.35 ≦ d / c ≦ 0.41, and 0.36 ≦ d / c ≦ 0.39. The inside is more preferable. When LiFSA is selected as the metal salt and DME is selected as the organic solvent, d / c is preferably in the range of 0.32 ≦ d / c ≦ 0.46, and in the range of 0.34 ≦ d / c ≦ 0.42. The inside is more preferable. When LiFSA is selected as the metal salt and AN is selected as the organic solvent, d / c is preferably in the range of 0.25 ≦ d / c ≦ 0.31, and in the range of 0.26 ≦ d / c ≦ 0.29. The inside is more preferable. When LiFSA is selected as the metal salt and DMC is selected as the organic solvent, d / c is preferably in the range of 0.32 ≦ d / c ≦ 0.48, and in the range of 0.32 ≦ d / c ≦ 0.46. The inside is preferable, and the inside of the range of 0.34 ≦ d / c ≦ 0.42 is more preferable. When LiFSA is selected as the metal salt and EMC is selected as the organic solvent, d / c is preferably in the range of 0.34 ≦ d / c ≦ 0.50, and in the range of 0.37 ≦ d / c ≦ 0.45. The inside is more preferable. When LiFSA is selected as the metal salt and DEC is selected as the organic solvent, d / c is preferably in the range of 0.36 ≦ d / c ≦ 0.54, and in the range of 0.39 ≦ d / c ≦ 0.48. The inside is more preferable.
　本発明の電解液の製造方法を説明する。本発明の電解液は従来の電解液と比較して金属塩の含有量が多いため、固体（粉体）の金属塩に有機溶媒を加える製造方法では凝集体が得られてしまい、溶液状態の電解液を製造するのが困難である。よって、本発明の電解液の製造方法においては、有機溶媒に対し金属塩を徐々に加え、かつ、電解液の溶液状態を維持しながら製造することが好ましい。 The method for producing the electrolytic solution of the present invention will be described. Since the electrolytic solution of the present invention has a higher metal salt content than the conventional electrolytic solution, the production method in which an organic solvent is added to a solid (powder) metal salt results in the formation of aggregates. It is difficult to produce an electrolytic solution. Therefore, in the manufacturing method of the electrolyte solution of this invention, it is preferable to manufacture, adding a metal salt gradually with respect to an organic solvent, and maintaining the solution state of electrolyte solution.
　金属塩と有機溶媒の種類に因り、本発明の電解液は、従来考えられてきた飽和溶解度を超えて金属塩が有機溶媒に溶解している液体を包含する。そのような本発明の電解液の製造方法は、ヘテロ元素を有する有機溶媒と金属塩とを混合し、金属塩を溶解して、第１電解液を調製する第１溶解工程と、撹拌及び／又は加温条件下、第１電解液に金属塩を加え、金属塩を溶解し、過飽和状態の第２電解液を調製する第２溶解工程と、撹拌及び／又は加温条件下、第２電解液に金属塩を加え、金属塩を溶解し、第３電解液を調製する第３溶解工程を含む。 Depending on the type of metal salt and organic solvent, the electrolytic solution of the present invention includes a liquid in which the metal salt is dissolved in the organic solvent beyond the conventionally considered saturation solubility. Such a method for producing an electrolytic solution of the present invention includes a first dissolution step of preparing a first electrolytic solution by mixing an organic solvent having a hetero element and a metal salt, dissolving the metal salt, stirring and / or Alternatively, a metal salt is added to the first electrolytic solution under heating conditions to dissolve the metal salt to prepare a supersaturated second electrolytic solution, and a second electrolysis under stirring and / or heating conditions. A metal salt is added to the solution to dissolve the metal salt, and a third dissolution step of preparing a third electrolytic solution is included.
　ここで、上記「過飽和状態」とは、撹拌及び／又は加温条件を解除した場合、又は、振動等の結晶核生成エネルギーを与えた場合に、電解液から金属塩結晶が析出する状態のことを意味する。第２電解液は「過飽和状態」であり、第１電解液及び第３電解液は「過飽和状態」でない。 Here, the “supersaturated state” means a state in which metal salt crystals are precipitated from the electrolyte when the stirring and / or heating conditions are canceled or when crystal nucleation energy such as vibration is applied. Means. The second electrolytic solution is “supersaturated”, and the first electrolytic solution and the third electrolytic solution are not “supersaturated”.
　換言すると、本発明の電解液の上記製造方法は、熱力学的に安定な液体状態であり従来の金属塩濃度を包含する第１電解液を経て、熱力学的に不安定な液体状態の第２電解液を経由し、そして、熱力学的に安定な新たな液体状態の第３電解液、すなわち本発明の電解液となる。 In other words, the above-described method for producing the electrolytic solution of the present invention is a thermodynamically stable liquid state, and passes through the first electrolytic solution containing the conventional metal salt concentration, and then the thermodynamically unstable liquid state. The second electrolytic solution passes through the two electrolytic solutions and becomes a thermodynamically stable new electrolytic third solution, that is, the electrolytic solution of the present invention.
　安定な液体状態の第３電解液は通常の条件で液体状態を保つことから、第３電解液においては、例えば、リチウム塩１分子に対し有機溶媒２分子で構成されこれらの分子間の強い配位結合によって安定化されたクラスターがリチウム塩の結晶化を阻害していると推定される。 Since the stable third electrolyte solution in a liquid state maintains a liquid state under normal conditions, the third electrolyte solution is composed of, for example, two molecules of an organic solvent for one lithium salt molecule, and a strong distribution between these molecules. It is presumed that the cluster stabilized by the coordinate bond inhibits the crystallization of the lithium salt.
　第１溶解工程は、ヘテロ原子を有する有機溶媒と金属塩とを混合し、金属塩を溶解して、第１電解液を調製する工程である。 The first dissolution step is a step of preparing a first electrolytic solution by mixing an organic solvent having a hetero atom and a metal salt to dissolve the metal salt.
　ヘテロ原子を有する有機溶媒と金属塩とを混合するためには、ヘテロ原子を有する有機溶媒に対し金属塩を加えても良いし、金属塩に対しヘテロ原子を有する有機溶媒を加えても良い。 In order to mix an organic solvent having a heteroatom and a metal salt, a metal salt may be added to the organic solvent having a heteroatom, or an organic solvent having a heteroatom may be added to the metal salt.
　第１溶解工程は、撹拌及び／又は加温条件下で行われるのが好ましい。撹拌速度については適宜設定すればよい。加温条件については、ウォーターバス又はオイルバスなどの恒温槽で適宜制御するのが好ましい。金属塩の溶解時には溶解熱が発生するので、熱に不安定な金属塩を用いる場合には、温度条件を厳密に制御することが好ましい。また、あらかじめ、有機溶媒を冷却しておいても良いし、第１溶解工程を冷却条件下で行ってもよい。 The first dissolution step is preferably performed under stirring and / or heating conditions. What is necessary is just to set suitably about stirring speed. About heating conditions, it is preferable to control suitably with thermostats, such as a water bath or an oil bath. Since heat of dissolution is generated when the metal salt is dissolved, it is preferable to strictly control the temperature condition when using a metal salt that is unstable to heat. In addition, the organic solvent may be cooled in advance, or the first dissolution step may be performed under cooling conditions.
　第１溶解工程と第２溶解工程は連続して実施しても良いし、第１溶解工程で得た第１電解液を一旦保管（静置）しておき、一定時間経過した後に、第２溶解工程を実施しても良い。 The first dissolution step and the second dissolution step may be performed continuously, or the first electrolytic solution obtained in the first dissolution step is temporarily stored (standing), and after a certain time has passed, You may implement a melt | dissolution process.
　第２溶解工程は、撹拌及び／又は加温条件下、第１電解液に金属塩を加え、金属塩を溶解し、過飽和状態の第２電解液を調製する工程である。 The second dissolution step is a step of preparing a supersaturated second electrolyte solution by adding a metal salt to the first electrolyte solution under stirring and / or heating conditions to dissolve the metal salt.
　第２溶解工程は、熱力学的に不安定な過飽和状態の第２電解液を調製するため、撹拌及び／又は加温条件下で行うことが必須である。ミキサー等の撹拌器を伴った撹拌装置で第２溶解工程を行うことにより、撹拌条件下としても良いし、撹拌子と撹拌子を動作させる装置（スターラー）を用いて第２溶解工程を行うことにより、撹拌条件下としても良い。加温条件については、ウォーターバス又はオイルバスなどの恒温槽で適宜制御するのが好ましい。もちろん、撹拌機能と加温機能を併せ持つ装置又はシステムを用いて第２溶解工程を行うことが特に好ましい。なお、電解液の製造方法でいう加温とは、対象物を常温（２５℃）以上の温度に温めることを指す。加温温度は３０℃以上であるのがより好ましく、３５℃以上であるのがさらに好ましい。また、加温温度は、有機溶媒の沸点よりも低い温度であるのが良い。 It is essential to perform the second dissolution step under stirring and / or warming conditions in order to prepare a thermodynamically unstable supersaturated second electrolyte solution. By performing the second dissolution step with a stirrer with a stirrer such as a mixer, the stirring condition may be achieved, or the second dissolution step is performed using a stirrer and a device (stirrer) that operates the stirrer. Thus, the stirring condition may be used. About heating conditions, it is preferable to control suitably with thermostats, such as a water bath or an oil bath. Of course, it is particularly preferable to perform the second dissolution step using an apparatus or system having both a stirring function and a heating function. In addition, the warming said by the manufacturing method of electrolyte solution refers to warming a target object to the temperature more than normal temperature (25 degreeC). The heating temperature is more preferably 30 ° C. or higher, and further preferably 35 ° C. or higher. Further, the heating temperature is preferably lower than the boiling point of the organic solvent.
　第２溶解工程において、加えた金属塩が十分に溶解しない場合には、撹拌速度の増加及び／又はさらなる加温を実施する。この場合には、第２溶解工程の電解液にヘテロ原子を有する有機溶媒を少量加えてもよい。 In the second dissolution step, if the added metal salt is not sufficiently dissolved, increase the stirring speed and / or further heating. In this case, a small amount of an organic solvent having a hetero atom may be added to the electrolytic solution in the second dissolution step.
　第２溶解工程で得た第２電解液を一旦静置すると金属塩の結晶が析出してしまうので、第２溶解工程と第３溶解工程は連続して実施するのが好ましい。 Since the crystal of the metal salt is deposited once the second electrolyte obtained in the second dissolution step is allowed to stand, the second dissolution step and the third dissolution step are preferably carried out continuously.
　第３溶解工程は、撹拌及び／又は加温条件下、第２電解液に金属塩を加え、金属塩を溶解し、第３電解液を調製する工程である。第３溶解工程では、過飽和状態の第２電解液に金属塩を加え、溶解する必要があるので、第２溶解工程と同様に撹拌及び／又は加温条件下で行うことが必須である。具体的な撹拌及び／又は加温条件は、第２溶解工程の条件と同様である。 The third dissolution step is a step of preparing a third electrolyte solution by adding a metal salt to the second electrolyte solution under stirring and / or heating conditions to dissolve the metal salt. In the third dissolution step, it is necessary to add a metal salt to the supersaturated second electrolytic solution and dissolve it. Therefore, it is essential to perform the stirring and / or heating conditions as in the second dissolution step. Specific stirring and / or heating conditions are the same as those in the second dissolution step.
　第１溶解工程、第２溶解工程及び第３溶解工程を通じて加えた有機溶媒と金属塩とのモル比が概ね２：１程度となれば、第３電解液（本発明の電解液）の製造が終了する。撹拌及び／又は加温条件を解除しても、本発明の電解液から金属塩結晶は析出しない。これらの事情からみて、本発明の電解液は、例えば、リチウム塩１分子に対し有機溶媒２分子からなり、これらの分子間の強い配位結合によって安定化されたクラスターを形成していると推定される。 If the molar ratio of the organic solvent and the metal salt added through the first dissolution step, the second dissolution step, and the third dissolution step is about 2: 1, the third electrolytic solution (the electrolytic solution of the present invention) can be manufactured. finish. Even when the stirring and / or heating conditions are canceled, the metal salt crystals are not precipitated from the electrolytic solution of the present invention. In view of these circumstances, the electrolytic solution of the present invention is composed of, for example, two molecules of an organic solvent for one molecule of a lithium salt, and is presumed to form a cluster stabilized by a strong coordinate bond between these molecules. Is done.
　なお、本発明の電解液を製造するにあたり、金属塩と有機溶媒の種類に因り、各溶解工程での処理温度において、上記過飽和状態を経由しない場合であっても、上記第１～３溶解工程で述べた具体的な溶解手段を用いて本発明の電解液を適宜製造することができる。 In producing the electrolytic solution of the present invention, depending on the types of metal salt and organic solvent, the first to third dissolving steps can be performed even if the supersaturated state is not passed at the treatment temperature in each dissolving step. The electrolytic solution of the present invention can be appropriately produced using the specific dissolution means described in 1.
　また、本発明の電解液の製造方法においては、製造途中の電解液を振動分光測定する振動分光測定工程を有するのが好ましい。具体的な振動分光測定工程としては、例えば、製造途中の各電解液を一部サンプリングして振動分光測定に供する方法でも良いし、各電解液をｉｎ　ｓｉｔｕ（その場）で振動分光測定する方法でも良い。電解液をｉｎ　ｓｉｔｕで振動分光測定する方法としては、透明なフローセルに製造途中の電解液を導入して振動分光測定する方法、又は、透明な製造容器を用いて該容器外からラマン測定する方法を挙げることができる。本発明の電解液の製造方法に振動分光測定工程を含めることにより、電解液におけるＩｓとＩｏとの関係を製造途中で確認できるため、製造途中の電解液が本発明の電解液に達したのか否かを判断することができるし、また、製造途中の電解液が本発明の電解液に達していない場合にどの程度の量の金属塩を追加すれば本発明の電解液に達するのかを把握することができる。 In addition, in the method for producing an electrolytic solution of the present invention, it is preferable to have a vibrational spectroscopic measurement step of performing vibrational spectroscopic measurement of the electrolytic solution being manufactured. As a specific vibration spectroscopic measurement step, for example, a method of sampling a part of each electrolytic solution in the middle of production and using it for vibration spectroscopic measurement, or a method of performing spectroscopic spectroscopic measurement of each electrolytic solution in situ (situ) But it ’s okay. As a method for in-vitro vibrational spectroscopic measurement of an electrolytic solution, a method of introducing an electrolytic solution in the middle of production into a transparent flow cell and performing vibrational spectroscopic measurement, or a method of performing Raman measurement from outside the container using a transparent production vessel Can be mentioned. Since the relationship between Is and Io in the electrolytic solution can be confirmed during the production by including the vibrational spectroscopic measurement step in the method for producing the electrolytic solution of the present invention, whether the electrolytic solution during the production reaches the electrolytic solution of the present invention. It is possible to determine whether or not the amount of metal salt added to reach the electrolytic solution of the present invention when the electrolytic solution being manufactured does not reach the electrolytic solution of the present invention. can do.
　本発明の電解液には、上記ヘテロ元素を有する有機溶媒以外に、低極性（低誘電率）又は低ドナー数であって、金属塩と特段の相互作用を示さない溶媒、すなわち、本発明の電解液における上記クラスターの形成及び維持に影響を与えない溶媒を加えることができる。このような溶媒を本発明の電解液に加えることにより、本発明の電解液の上記クラスターの形成を保持したままで、電解液の粘度を低くする効果が期待できる。 In the electrolyte solution of the present invention, in addition to the organic solvent having a hetero element, the solvent has a low polarity (low dielectric constant) or a low donor number and does not exhibit a special interaction with the metal salt, that is, the present invention. A solvent that does not affect the formation and maintenance of the clusters in the electrolyte can be added. By adding such a solvent to the electrolytic solution of the present invention, an effect of lowering the viscosity of the electrolytic solution can be expected while maintaining the formation of the cluster of the electrolytic solution of the present invention.
　金属塩と特段の相互作用を示さない溶媒としては、具体的にベンゼン、トルエン、エチルベンゼン、ｏ－キシレン、ｍ－キシレン、ｐ－キシレン、１－メチルナフタレン、ヘキサン、ヘプタン、シクロヘキサンを例示することができる。 Specific examples of the solvent that does not exhibit a special interaction with the metal salt include benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, 1-methylnaphthalene, hexane, heptane, and cyclohexane. it can.
　また、本発明の電解液には、上記ヘテロ元素を有する有機溶媒以外に、難燃性の溶媒を加えることができる。難燃性の溶媒を本発明の電解液に加えることにより、本発明の電解液の安全度をさらに高めることができる。難燃性の溶媒としては、四塩化炭素、テトラクロロエタン、ハイドロフルオロエーテルなどのハロゲン系溶媒、リン酸トリメチル、リン酸トリエチルなどのリン酸誘導体を例示することができる。 In addition to the organic solvent having a hetero element, a flame retardant solvent can be added to the electrolytic solution of the present invention. By adding a flame retardant solvent to the electrolytic solution of the present invention, the safety of the electrolytic solution of the present invention can be further increased. Examples of the flame retardant solvent include halogen solvents such as carbon tetrachloride, tetrachloroethane, and hydrofluoroether, and phosphoric acid derivatives such as trimethyl phosphate and triethyl phosphate.
　さらに、本発明の電解液をポリマーや無機フィラーと混合し混合物とすると、当該混合物が電解液を封じ込め、擬似固体電解質となる。擬似固体電解質を電池の電解液として用いることで、電池における電解液の液漏れを抑制することができる。 Furthermore, when the electrolytic solution of the present invention is mixed with a polymer or an inorganic filler to form a mixture, the mixture contains the electrolytic solution and becomes a pseudo solid electrolyte. By using the pseudo-solid electrolyte as the battery electrolyte, leakage of the electrolyte in the battery can be suppressed.
　上記ポリマーとしては、リチウムイオン二次電池などの電池に使用されるポリマーや一般的な化学架橋したポリマーを採用することができる。特に、ポリフッ化ビニリデンやポリヘキサフルオロプロピレンなど電解液を吸収しゲル化し得るポリマーや、ポリエチレンオキシドなどのポリマーにイオン導電性基を導入したものが好適である。 As the polymer, a polymer used for a battery such as a lithium ion secondary battery or a general chemically crosslinked polymer can be employed. In particular, a polymer that can absorb an electrolyte such as polyvinylidene fluoride and polyhexafluoropropylene and gel can be used, and a polymer such as polyethylene oxide in which an ion conductive group is introduced.
　具体的なポリマーとしては、ポリメチルアクリレート、ポリメチルメタクリレート、ポリエチレンオキシド、ポリプロピレンオキシド、ポリアクリロニトリル、ポリフッ化ビニリデン、ポリエチレングリコールジメタクリレート、ポリエチレングリコールアクリレート、ポリグリシドール、ポリテトラフルオロエチレン、ポリヘキサフルオロプロピレン、ポリシロキサン、ポリ酢酸ビニル、ポリビニルアルコール、ポリアクリル酸、ポリメタクリル酸、ポリイタコン酸、ポリフマル酸、ポリクロトン酸、ポリアンゲリカ酸、カルボキシメチルセルロースなどのポリカルボン酸、スチレン－ブタジエンゴム、ニトリル－ブタジエンゴム、ポリスチレン、ポリカーボネート、無水マレイン酸とグリコール類を共重合した不飽和ポリエステル、置換基を有するポリエチレンオキシド誘導体、フッ化ビニリデンとヘキサフルオロプロピレンとの共重合体を例示できる。また、上記ポリマーとして、上記具体的なポリマーを構成する二種類以上のモノマーを共重合させた共重合体を選択しても良い。 Specific polymers include polymethyl acrylate, polymethyl methacrylate, polyethylene oxide, polypropylene oxide, polyacrylonitrile, polyvinylidene fluoride, polyethylene glycol dimethacrylate, polyethylene glycol acrylate, polyglycidol, polytetrafluoroethylene, polyhexafluoropropylene, Polycarboxylic acid such as polysiloxane, polyvinyl acetate, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyitaconic acid, polyfumaric acid, polycrotonic acid, polyangelic acid, carboxymethylcellulose, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene , Polycarbonate, unsaturated polyester copolymerized with maleic anhydride and glycols, Polyethylene oxide derivative having a group, a copolymer of vinylidene fluoride and hexafluoropropylene can be exemplified. Further, as the polymer, a copolymer obtained by copolymerizing two or more monomers constituting the specific polymer may be selected.
　上記ポリマーとして、多糖類も好適である。具体的な多糖類として、グリコーゲン、セルロース、キチン、アガロース、カラギーナン、ヘパリン、ヒアルロン酸、ペクチン、アミロペクチン、キシログルカン、アミロースを例示できる。また、これら多糖類を含む材料を上記ポリマーとして採用してもよく、当該材料として、アガロースなどの多糖類を含む寒天を例示することができる。 Polysaccharides are also suitable as the polymer. Specific examples of the polysaccharide include glycogen, cellulose, chitin, agarose, carrageenan, heparin, hyaluronic acid, pectin, amylopectin, xyloglucan, and amylose. Moreover, you may employ | adopt the material containing these polysaccharides as said polymer, The agar containing polysaccharides, such as agarose, can be illustrated as the said material.
　上記無機フィラーとしては、酸化物や窒化物などの無機セラミックスが好ましい。 The inorganic filler is preferably an inorganic ceramic such as oxide or nitride.
　無機セラミックスはその表面に親水性及び疎水性の官能基を有している。そのため、当該官能基が電解液を引き付けることにより、無機セラミックス内に導電性通路が形成され得る。さらに、電解液で分散した無機セラミックスは前記官能基により無機セラミックス同士のネットワークを形成し、電解液を封じ込める役割を果たし得る。無機セラミックスのこのような機能により、電池における電解液の液漏れをさらに好適に抑制することができる。無機セラミックスの上記機能を好適に発揮するために、無機セラミックスは粒子形状のものが好ましく、特にその粒子径がナノ水準のものが好ましい。 Inorganic ceramics have hydrophilic and hydrophobic functional groups on the surface. Therefore, when the functional group attracts the electrolytic solution, a conductive path can be formed in the inorganic ceramic. Furthermore, the inorganic ceramics dispersed in the electrolytic solution can form a network between the inorganic ceramics by the functional groups and serve to contain the electrolytic solution. With such a function of the inorganic ceramics, it is possible to more suitably suppress the leakage of the electrolytic solution in the battery. In order to suitably exhibit the above functions of the inorganic ceramics, the inorganic ceramics preferably have a particle shape, and particularly preferably have a particle size of nano level.
　無機セラミックスの種類としては、一般的なアルミナ、シリカ、チタニア、ジルコニア、リチウムリン酸塩などを挙げることができる。また、無機セラミックス自体にリチウム伝導性があるものでも良く、具体的には、Ｌｉ３Ｎ、ＬｉＩ、ＬｉＩ－Ｌｉ３Ｎ－ＬｉＯＨ、ＬｉＩ－Ｌｉ２Ｓ－Ｐ２Ｏ５、ＬｉＩ－Ｌｉ２Ｓ－Ｐ２Ｓ５、ＬｉＩ－Ｌｉ２Ｓ－Ｂ２Ｓ３、Ｌｉ２Ｏ－Ｂ２Ｓ３、Ｌｉ２Ｏ－Ｖ２Ｏ３－ＳｉＯ２、Ｌｉ２Ｏ－Ｂ２Ｏ３－Ｐ２Ｏ５、Ｌｉ２Ｏ－Ｂ２Ｏ３－ＺｎＯ、Ｌｉ２Ｏ－Ａｌ２Ｏ３－ＴｉＯ２－ＳｉＯ２－Ｐ２Ｏ５、ＬｉＴｉ２（ＰＯ４）３、Ｌｉ－βＡｌ２Ｏ３、ＬｉＴａＯ３を例示することができる。 Examples of the inorganic ceramics include general alumina, silica, titania, zirconia, and lithium phosphate. Further, the inorganic ceramic itself may be lithium conductive, and specifically, Li 3 N, LiI, LiI—Li 3 N—LiOH, LiI—Li 2 S—P 2 O 5 , LiI—Li 2 S —P 2 S 5 , LiI—Li 2 S—B 2 S 3 , Li 2 O—B 2 S 3 , Li 2 O—V 2 O 3 —SiO 2 , Li 2 O—B 2 O 3 —P 2 O 5 , Li 2 O—B 2 O 3 —ZnO, Li 2 O—Al 2 O 3 —TiO 2 —SiO 2 —P 2 O 5 , LiTi 2 (PO 4 ) 3 , Li—βAl 2 O 3 , LiTaO 3 Can be illustrated.
　無機フィラーとしてガラスセラミックスを採用してもよい。ガラスセラミックスはイオン性液体を封じ込めることができるので、本発明の電解液に対しても同様の効果を期待できる。ガラスセラミックスとしては、ｘＬｉ２Ｓ－（１－ｘ）Ｐ２Ｓ５で表される化合物、並びに、当該化合物のＳの一部を他の元素で置換したもの、及び、当該化合物のＰの一部をゲルマニウムに置換したものを例示できる。 Glass ceramics may be employed as the inorganic filler. Since glass ceramics can contain an ionic liquid, the same effect can be expected for the electrolytic solution of the present invention. Glass ceramics include a compound represented by xLi 2 S- (1-x) P 2 S 5 , a compound obtained by substituting a part of S of the compound with another element, and a P of the compound. An example in which the part is replaced with germanium can be exemplified.
　以上説明した本発明の電解液は、優れたイオン伝導度を示すので、電池など蓄電装置の電解液として好適に使用される。特に、二次電池の電解液として使用されるのが好ましく、中でもリチウムイオン二次電池の電解液として使用されるのが好ましい。 Since the electrolytic solution of the present invention described above exhibits excellent ionic conductivity, it is suitably used as an electrolytic solution for power storage devices such as batteries. In particular, it is preferably used as an electrolyte solution for a secondary battery, and particularly preferably used as an electrolyte solution for a lithium ion secondary battery.
　ところで、本発明の非水電解質二次電池における負極および／または正極の表面にはＳ，Ｏ含有皮膜が形成されている。後述するように、この皮膜はＳおよびＯを含み、少なくともＳ＝Ｏ構造を有する。そして、このＳ，Ｏ含有皮膜は、Ｓ＝Ｏ構造を有するため、電解液に由来するものであると考えられる。本発明の電解液の中では、通常の電解液に比べて、Ｌｉカチオンとアニオンとが近くに存在すると考えられる。このためアニオンはＬｉカチオンからの静電的な影響を強く受けることで優先的に還元分解される。一般的な電解液を用いた一般的な非水電解質二次電池においては、電解液に含まれる有機溶媒（例えばＥＣ：エチレンカーボネート等）が還元分解され、当該有機溶媒の分解生成物によってＳＥＩ皮膜が構成される。しかし、上述したように本発明の非水電解質二次電池に含まれる本発明の電解液においてはアニオンが優先的に還元分解される。このため、本発明の非水電解質二次電池におけるＳＥＩ皮膜、つまりＳ，Ｏ含有皮膜には、アニオンに由来するＳ＝Ｏ構造が多く含まれると考えられる。つまり、通常の電解液を用いた通常の非水電解質二次電池においては、ＥＣ等の有機溶媒の分解物に由来するＳＥＩ皮膜が電極表面に定着する。一方、本発明の電解液を用いた本発明の非水電解質二次電池においては、主として金属塩のアニオンに由来するＳＥＩ皮膜が電極表面に定着する。 Incidentally, an S, O-containing film is formed on the surface of the negative electrode and / or the positive electrode in the nonaqueous electrolyte secondary battery of the present invention. As will be described later, this film contains S and O, and has at least an S═O structure. And since this S, O containing film | membrane has a S = O structure, it is thought that it originates in electrolyte solution. In the electrolytic solution of the present invention, it is considered that the Li cation and the anion are present in the vicinity as compared with a normal electrolytic solution. For this reason, the anion is preferentially reduced and decomposed by being strongly affected by the electrostatic influence from the Li cation. In a general non-aqueous electrolyte secondary battery using a general electrolytic solution, an organic solvent (for example, EC: ethylene carbonate) contained in the electrolytic solution is reduced and decomposed, and an SEI film is formed by a decomposition product of the organic solvent. Is configured. However, as described above, in the electrolytic solution of the present invention included in the nonaqueous electrolyte secondary battery of the present invention, anions are preferentially reduced and decomposed. For this reason, it is considered that the SEI film, that is, the S, O-containing film in the non-aqueous electrolyte secondary battery of the present invention contains a lot of S═O structures derived from anions. That is, in a normal nonaqueous electrolyte secondary battery using a normal electrolyte solution, an SEI film derived from a decomposition product of an organic solvent such as EC is fixed on the electrode surface. On the other hand, in the nonaqueous electrolyte secondary battery of the present invention using the electrolytic solution of the present invention, the SEI film mainly derived from the anion of the metal salt is fixed on the electrode surface.
　また、理由は定かではないが、本発明の非水電解質二次電池におけるＳ，Ｏ含有皮膜は充放電に伴って状態変化する。例えば、後述するように、充放電の状態によってはＳ，Ｏ含有皮膜の厚さやＳ、Ｏ等の元素の割合が変化する場合がある。このため、本発明の非水電解質二次電池におけるＳ，Ｏ含有皮膜には、上述したアニオンの分解物に由来し皮膜中に定着する部分（以下、必要に応じて定着部と呼ぶ）と、充放電に伴って可逆的に増減する部分（以下、必要に応じて吸着部と呼ぶ）とが存在すると考えられる。そして吸着部は、定着部と同様に金属塩のアニオンに由来するＳ＝Ｏ等の構造を有すると推測される。 Moreover, although the reason is not certain, the state of the S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention changes with charge / discharge. For example, as will be described later, depending on the state of charge and discharge, the thickness of the S, O-containing film and the ratio of elements such as S, O may change. For this reason, the S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention is derived from the above-described decomposition product of anions and fixed in the film (hereinafter referred to as a fixing unit as required), It is considered that there is a portion that reversibly increases / decreases with charge / discharge (hereinafter referred to as an adsorption portion as necessary). The adsorption part is presumed to have a structure such as S═O derived from the anion of the metal salt as in the fixing part.
　なお、Ｓ，Ｏ含有皮膜は電解液の分解物で構成され、その他吸着物を含むと考えられるため、Ｓ，Ｏ含有皮膜の大部分（または全て）は非水電解質二次電池の初回充放電時以降に生成すると考えられる。つまり、本発明の非水電解質二次電池は、使用時において、負極の表面および／または正極の表面にＳ，Ｏ含有皮膜を有する。Ｓ，Ｏ含有皮膜のその他の構成成分は、電解液に含まれる硫黄および酸素以外の成分や、負極の組成等に応じて種々に異なる。また、当該Ｓ，Ｏ含有皮膜はＳ＝Ｏ構造を含みさえすれば良く、その含有割合は特に限定されない。さらに、Ｓ，Ｏ含有皮膜に含まれるＳ＝Ｏ構造以外の成分および量は特に限定されない。そして、Ｓ，Ｏ含有皮膜は負極表面にのみ形成されても良いし、正極表面にのみ形成されても良い。しかしながら、上述したようにＳ，Ｏ含有皮膜は本発明の電解液に含まれる金属塩のアニオンに由来すると考えられるため、当該金属塩のアニオンに由来する成分をその他の成分よりも多く含むのが好ましい。また、Ｓ，Ｏ含有皮膜は負極表面および正極表面の両方に形成されるのが好ましい。以下、必要に応じて、負極の表面に形成されたＳ，Ｏ含有皮膜を負極Ｓ，Ｏ含有皮膜と呼び、正極の表面に形成されたＳ，Ｏ含有皮膜を正極Ｓ，Ｏ含有皮膜と呼ぶ。 Since the S, O-containing film is composed of a decomposition product of the electrolytic solution and is thought to contain other adsorbents, most (or all) of the S, O-containing film is the first charge / discharge of the nonaqueous electrolyte secondary battery. It is considered to be generated after the hour. That is, the nonaqueous electrolyte secondary battery of the present invention has an S, O-containing film on the surface of the negative electrode and / or the surface of the positive electrode in use. Other constituent components of the S, O-containing coating are variously different depending on components other than sulfur and oxygen contained in the electrolytic solution, the composition of the negative electrode, and the like. Moreover, the said S, O containing film should just contain S = O structure, and the content rate is not specifically limited. Furthermore, components and amounts other than the S═O structure contained in the S, O-containing coating are not particularly limited. The S, O-containing film may be formed only on the negative electrode surface, or may be formed only on the positive electrode surface. However, as described above, since the S, O-containing film is considered to be derived from the anion of the metal salt contained in the electrolytic solution of the present invention, it contains more components derived from the anion of the metal salt than the other components. preferable. In addition, the S, O-containing film is preferably formed on both the negative electrode surface and the positive electrode surface. Hereinafter, the S, O-containing film formed on the surface of the negative electrode is referred to as the negative electrode S, O-containing film, and the S, O-containing film formed on the surface of the positive electrode is referred to as the positive electrode S, O-containing film as necessary. .
　上述したように、本発明の電解液における金属塩としてイミド塩を好ましく用いることができる。従来から、電解液にイミド塩を添加する技術は知られており、この種の電解液を用いた非水電解質二次電池においては、正極および／または負極上の皮膜は、電解液の有機溶媒分解物に由来する化合物に加え、イミド塩由来の化合物、つまりＳを含む化合物を含むことが知られている。例えば特開２０１３－１４５７３２には、この皮膜に一部含まれるイミド塩由来の成分によって、非水電解質二次電池の内部抵抗の増大を抑制しつつ非水電解質二次電池の耐久性を向上させ得ることが紹介されている。 As described above, an imide salt can be preferably used as the metal salt in the electrolytic solution of the present invention. Conventionally, a technique for adding an imide salt to an electrolytic solution is known. In a non-aqueous electrolyte secondary battery using this type of electrolytic solution, the coating on the positive electrode and / or the negative electrode is an organic solvent of the electrolytic solution. In addition to compounds derived from decomposition products, it is known to include compounds derived from imide salts, that is, compounds containing S. For example, in JP2013-145732A, a component derived from an imide salt partially contained in this film improves the durability of the nonaqueous electrolyte secondary battery while suppressing an increase in the internal resistance of the nonaqueous electrolyte secondary battery. It has been introduced to get.
　しかしながら、上記した従来技術では、以下の理由から皮膜中のイミド塩由来成分を濃化することはできなかった。先ず、負極活物質として黒鉛を用いる場合、黒鉛を電荷担体に対して可逆的に反応させ、非水電解質二次電池を可逆的に充放電させるためには、負極の表面にＳＥＩ皮膜が形成されている必要があると考えられている。従来は、このＳＥＩ皮膜を形成するために、ＥＣを代表とする環状カーボネート化合物を電解液用の有機溶媒として用いていた。そして、当該環状カーボネート化合物の分解物によりＳＥＩ皮膜を形成していた。つまり、イミド塩を含む従来の電解液は、有機溶媒としてＥＣ等の環状カーボネートを多く含有するとともに、添加剤としてイミド塩を含んでいた。しかしこの場合、ＳＥＩ皮膜の主成分は有機溶媒に由来する成分となり、ＳＥＩ皮膜のイミド塩の含有量を増大させるのは困難であった。また、イミド塩を添加剤としてではなく金属塩（つまり電解質塩、支持塩）として用いようとする場合、正極用の集電体との組み合わせを考慮する必要があった。つまり、イミド塩は、正極用の集電体として一般に用いられているアルミニウム集電体を腐食することが知られている。このため、特に４Ｖ程度の電位で作動する正極を用いる場合は、アルミニウムと不動体を形成するＬｉＰＦ６等を電解質塩とした電解液をアルミニウム集電体と共存させる必要がある。また従来の電解液ではＬｉＰＦ６やイミド塩等からなる電解質塩の合計濃度は、イオン伝導度や粘度の観点から、１ｍｏｌ／Ｌ～２ｍｏｌ／Ｌ程度が最適とされている（特開２０１３－１４５７３２）。したがってＬｉＰＦ６を充分な量添加すると、必然的にイミド塩の添加量は低減するため、イミド塩を電解液用の金属塩として多量に使用し難い問題があった。以下、必要に応じて、イミド塩を単に金属塩と略する場合がある。 However, the above-described conventional technology cannot concentrate the imide salt-derived component in the coating for the following reasons. First, when graphite is used as the negative electrode active material, an SEI film is formed on the surface of the negative electrode in order to cause the graphite to react reversibly with the charge carrier and to reversibly charge and discharge the nonaqueous electrolyte secondary battery. It is considered necessary to be. Conventionally, in order to form this SEI film, a cyclic carbonate compound typified by EC has been used as an organic solvent for the electrolytic solution. And the SEI membrane | film | coat was formed with the decomposition product of the said cyclic carbonate compound. That is, the conventional electrolyte solution containing an imide salt contains a large amount of cyclic carbonate such as EC as an organic solvent and also contains an imide salt as an additive. However, in this case, the main component of the SEI film is a component derived from an organic solvent, and it is difficult to increase the content of the imide salt of the SEI film. Further, when an imide salt is used as a metal salt (that is, an electrolyte salt or a supporting salt) rather than as an additive, it is necessary to consider a combination with a current collector for a positive electrode. That is, imide salts are known to corrode aluminum current collectors that are generally used as current collectors for positive electrodes. For this reason, when using the positive electrode which operates at a potential of about 4 V in particular, it is necessary to coexist with an aluminum current collector an electrolytic solution containing LiPF 6 or the like that forms an immobile with aluminum as an electrolyte salt. In the conventional electrolytic solution, the total concentration of the electrolyte salt composed of LiPF 6 or imide salt is optimally about 1 mol / L to 2 mol / L from the viewpoint of ionic conductivity and viscosity (Japanese Patent Laid-Open No. 2013-145732). ). Therefore, when a sufficient amount of LiPF 6 is added, the amount of imide salt added is inevitably reduced, so that there is a problem that it is difficult to use a large amount of imide salt as a metal salt for an electrolytic solution. Hereinafter, if necessary, the imide salt may be simply abbreviated as a metal salt.
　これに対して、本発明の電解液は金属塩を高濃度で含む。そして後述するように、本発明の電解液中において、金属塩は従来とは全く異なる状態で存在していると考えられる。このため、本発明の電解液では、従来の電解液とは異なり、金属塩が高濃度であることに由来する問題は生じ難い。例えば、本発明の電解液によると、電解液の粘度上昇による非水電解質二次電池の入出力性能の低下を抑制できるし、アルミニウム集電体の腐食を抑制することも可能である。また、電解液に高濃度で含まれる金属塩は、負極上で優先的に還元分解される。その結果、有機溶媒としてＥＣ等の環状カーボネート化合物を用いなくても、金属塩に由来する特殊構造のＳＥＩ皮膜、つまりＳ，Ｏ含有皮膜が負極上に形成される。このため本発明の非水電解質二次電池は、負極活物質として黒鉛を用いる場合にも、有機溶媒に環状カーボネート化合物を用いることなく可逆的に充放電可能である。 In contrast, the electrolytic solution of the present invention contains a metal salt at a high concentration. As will be described later, in the electrolytic solution of the present invention, it is considered that the metal salt is present in a state completely different from the conventional one. For this reason, in the electrolytic solution of the present invention, unlike the conventional electrolytic solution, a problem caused by the high concentration of the metal salt hardly occurs. For example, according to the electrolytic solution of the present invention, it is possible to suppress a decrease in input / output performance of the nonaqueous electrolyte secondary battery due to an increase in the viscosity of the electrolytic solution, and it is also possible to suppress corrosion of the aluminum current collector. Further, the metal salt contained in the electrolytic solution at a high concentration is preferentially reduced and decomposed on the negative electrode. As a result, an SEI film having a special structure derived from a metal salt, that is, an S, O-containing film is formed on the negative electrode without using a cyclic carbonate compound such as EC as the organic solvent. Therefore, the nonaqueous electrolyte secondary battery of the present invention can be reversibly charged and discharged without using a cyclic carbonate compound as an organic solvent even when graphite is used as the negative electrode active material.
　このため本発明の非水電解質二次電池は、負極活物質として黒鉛を用いかつ正極用集電体としてアルミニウム集電体を用いる場合においても、有機溶媒として環状カーボネート化合物を用いたり金属塩としてＬｉＰＦ６を用いたりすることなく、可逆的に充放電可能である。さらに、負極および／または正極表面のＳＥＩ皮膜の大部分をアニオン由来成分で構成することが可能となる。後述するように、アニオン由来成分を含むＳ，Ｏ含有皮膜によると非水電解質二次電池の電池特性を向上させ得る。 Therefore, the nonaqueous electrolyte secondary battery of the present invention uses a cyclic carbonate compound as the organic solvent or LiPF as the metal salt even when graphite is used as the negative electrode active material and an aluminum current collector is used as the positive electrode current collector. 6 can be reversibly charged / discharged. Furthermore, most of the SEI film on the negative electrode and / or positive electrode surface can be composed of anion-derived components. As will be described later, the S, O-containing film containing an anion-derived component can improve the battery characteristics of the nonaqueous electrolyte secondary battery.
　なお、ＥＣ溶媒を含む一般的な電解液を用いた非水電解質二次電池において負極の皮膜には、ＥＣ溶媒に由来する炭素が重合したポリマー構造が多く含まれる。これに対して、本発明の非水電解質二次電池における負極Ｓ，Ｏ含有皮膜には、このような炭素が重合したポリマー構造は殆ど（または全く）含まれず、金属塩のアニオンに由来する構造を多く含む。正極皮膜に関しても同様である。 Note that in the nonaqueous electrolyte secondary battery using a general electrolytic solution containing an EC solvent, the negative electrode film includes many polymer structures in which carbon derived from the EC solvent is polymerized. On the other hand, the negative electrode S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention contains almost no (or no) polymer structure obtained by polymerizing such carbon, and is derived from an anion of a metal salt. Including many. The same applies to the positive electrode film.
　ところで、本発明の電解液は金属塩のカチオンを高濃度で含有する。このため、本発明の電解液中において、隣り合うカチオン間の距離は極めて近い。そして、非水電解質二次電池の充放電時にリチウムイオン等のカチオンが正極と負極との間を移動する際には、移動先の電極に直近のカチオンが先ず当該電極に供給される。そして、供給された当該カチオンがあった場所には、当該カチオンに隣り合う他のカチオンが移動する。つまり、本発明の電解液中においては、隣り合うカチオンが供給対象となる電極に向けて順番に一つずつ位置を変えるという、ドミノ倒し様の現象が生じていると予想される。このため、充放電時のカチオンの移動距離は短く、その分だけカチオンの移動速度が高いと考えられる。そして、このことに起因して、本発明の電解液を有する本発明の非水電解質二次電池の反応速度は高いと考えられる。また、本発明の非水電解質二次電池は電極（つまり負極および／または正極）にＳ，Ｏ含有皮膜を有し、当該Ｓ，Ｏ含有皮膜はＳ＝Ｏ構造を有するとともに多くのカチオンを含むと考えられる。このＳ，Ｏ含有皮膜に含まれるカチオンは電極に優先的に供給されると考えられる。よって、本発明の非水電解質二次電池においては、電極近傍に豊富なカチオン源（つまりＳ，Ｏ含有皮膜）を有することによってもカチオンの輸送速度がさらに向上すると考えられる。したがって、本発明の非水電解質二次電池においては、本発明の電解液とＳ，Ｏ含有皮膜との協働によって、優れた電池特性が発揮されると考えられる。 Incidentally, the electrolytic solution of the present invention contains a metal salt cation in a high concentration. For this reason, in the electrolytic solution of the present invention, the distance between adjacent cations is extremely short. When cations such as lithium ions move between the positive electrode and the negative electrode during charge / discharge of the nonaqueous electrolyte secondary battery, the cations closest to the destination electrode are first supplied to the electrode. And the other cation adjacent to the said cation moves to the place with the said supplied cation. In other words, in the electrolytic solution of the present invention, it is expected that a domino-like phenomenon occurs in which adjacent cations change one by one toward the electrode to be supplied one by one. For this reason, the movement distance of the cation at the time of charging / discharging is short, and it is thought that the movement speed | rate of a cation is high by that much. Due to this, the reaction rate of the nonaqueous electrolyte secondary battery of the present invention having the electrolytic solution of the present invention is considered to be high. In addition, the nonaqueous electrolyte secondary battery of the present invention has an S, O-containing film on an electrode (that is, a negative electrode and / or a positive electrode), and the S, O-containing film has an S═O structure and contains many cations. it is conceivable that. It is considered that cations contained in the S, O-containing film are preferentially supplied to the electrode. Therefore, in the nonaqueous electrolyte secondary battery of the present invention, it is considered that the cation transport rate is further improved by having an abundant cation source (that is, an S, O-containing film) in the vicinity of the electrode. Therefore, in the nonaqueous electrolyte secondary battery of the present invention, it is considered that excellent battery characteristics are exhibited by the cooperation of the electrolytic solution of the present invention and the S, O-containing film.
　参考までに、負極のＳＥＩ皮膜は、所定以下の電圧で電解液が還元分解し、その際に生成した電解液の堆積物によって構成されると考えられている。つまり、負極の表面に上述したＳ，Ｏ含有皮膜を効率良く生成させるためには、本発明の非水電解質二次電池は、負極の電位の最小値が所定以下になるようにするのが良い。具体的には、本発明の非水電解質二次電池は、対極をリチウムにした場合に負極の電位の最小値が１．３Ｖ以下となる条件で使用する電池として好適である。 For reference, it is considered that the SEI film of the negative electrode is constituted by a deposit of the electrolytic solution generated by reductive decomposition of the electrolytic solution at a predetermined voltage or less. That is, in order to efficiently generate the above-described S, O-containing film on the surface of the negative electrode, the non-aqueous electrolyte secondary battery of the present invention should have the minimum value of the negative electrode potential not more than a predetermined value. . Specifically, the nonaqueous electrolyte secondary battery of the present invention is suitable as a battery to be used under the condition that the minimum value of the negative electrode potential is 1.3 V or less when the counter electrode is lithium.
　本発明の第４の態様に係る非水系二次電池の使用最高電位は、Ｌｉ／Ｌｉ＋を基準電位としたとき４．５Ｖ以上である。ここで「使用最高電位」とは、正極活物質の崩壊を招かない範囲内で制御した電池の充電終止時における正極電位（Ｌｉ／Ｌｉ＋基準電位）を意味し、本発明で用いている電解液は、高い電位でも分解されにくい。 The maximum use potential of the non-aqueous secondary battery according to the fourth aspect of the present invention is 4.5 V or more when Li / Li + is a reference potential. Here, the “maximum potential used” means the positive electrode potential (Li / Li + reference potential) at the end of charging of the battery controlled within a range that does not cause the collapse of the positive electrode active material. The liquid is not easily decomposed even at a high potential.
　その理由は次のように考えられる。上記の電解液は、電解液の振動分光スペクトルにおける有機溶媒由来のピーク強度について、有機溶媒本来のピークの強度をＩ０とし、有機溶媒本来のピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏとしている。この電解液では、ほぼすべての有機溶媒と金属塩中のＬｉイオン及びアニオンが相互的に静電引力で引き合い、フリーの状態の溶媒が極めて少ない。多くの有機溶媒は、金属塩とクラスターを形成していて、エネルギー的に安定である。このため、従来の電解液に対して耐酸化性の向上が期待できる。よって、４．５Ｖ以上の高電位でも分解されにくいと考えられる。このため、電池の正極の使用最高電位を、４．５Ｖ以上と高くすることができる。 The reason is considered as follows. In the above electrolyte solution, regarding the peak intensity derived from the organic solvent in the vibrational spectroscopic spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is I 0 and the intensity of the peak shifted from the original peak of the organic solvent is Is, Is> Io. In this electrolytic solution, almost all organic solvents and Li ions and anions in the metal salt are attracted to each other by electrostatic attraction, and the amount of the solvent in a free state is extremely small. Many organic solvents form clusters with metal salts and are energetically stable. For this reason, improvement in oxidation resistance can be expected with respect to the conventional electrolyte. Therefore, it is considered that decomposition is difficult even at a high potential of 4.5 V or higher. For this reason, the maximum use potential of the positive electrode of the battery can be increased to 4.5 V or more.
　したがって、高い電位で充電反応するリチウム金属複合酸化物やポリアニオン系材料を正極活物質として用いることができる。たとえば、平均反応電位が４．５Ｖ以上のリチウム金属複合酸化物を正極活物質として用いることができる。 Therefore, a lithium metal composite oxide or a polyanionic material that undergoes a charging reaction at a high potential can be used as the positive electrode active material. For example, a lithium metal composite oxide having an average reaction potential of 4.5 V or more can be used as the positive electrode active material.
　また、平均反応電位が４．５Ｖ未満のリチウム金属複合酸化物でも、４．５Ｖ以上の電位まで充電して用いることも可能である。 In addition, even a lithium metal composite oxide having an average reaction potential of less than 4.5V can be charged to a potential of 4.5V or more.
　以上のことから、リチウム金属複合酸化物やポリアニオン系材料と上記の電解液を組み合わせた非水系二次電池によれば、正極の使用最高電位を従来よりも高い４．５Ｖ以上とすることができる。正極の使用最高電位の上限を述べると、６．０Ｖ又は５．７Ｖを例示することができる。 From the above, according to the non-aqueous secondary battery in which the lithium metal composite oxide or polyanion material and the above electrolyte are combined, the maximum use potential of the positive electrode can be set to 4.5 V or higher, which is higher than the conventional one. . When the upper limit of the maximum use potential of the positive electrode is described, 6.0 V or 5.7 V can be exemplified.
　上記の電解液の酸化分解電位は、Ｌｉ＋／Ｌｉ電極基準で４．５Ｖ以上であることが好ましい。この場合には、４．５Ｖ以上の高い正極電位での電池使用時にも電解液の酸化分解を抑えることができる。上記の電解液の酸化分解電位の上限を述べると、６．０Ｖ又は５．７Ｖを例示することができる。 The oxidative decomposition potential of the electrolytic solution is preferably 4.5 V or more on the basis of the Li + / Li electrode. In this case, oxidative decomposition of the electrolytic solution can be suppressed even when the battery is used at a high positive electrode potential of 4.5 V or higher. When the upper limit of the oxidative decomposition potential of the electrolytic solution is described, 6.0 V or 5.7 V can be exemplified.
　上記の電解液と、作用極としての白金と、対極としてのリチウム金属とを備えた電池についてリニアスイープボルタンメトリー（ＬＳＶ）の測定を行い、前記測定により形成された電流―電位曲線は、Ｌｉ＋／Ｌｉ電極を基準電位とした電位４．５Ｖ以上、さらには５．０Ｖ以上で、立ち上がり部を示すことが好ましい。このような特性をもつ電解液は、少なくとも電位４．５Ｖまで酸化分解しないと考えられる。ＬＳＶは、電極の電位を連続的に変化させたときに流れる電流値を測定する評価法である。非水系二次電池についてＬＳＶを測定することにより非水系二次電池の電位－電流曲線が作成される。電位―電流曲線において、電位の増加量に対する電流値の増加量の比率を、電流増加率とする。この増加率は、電圧印加直後では低い。所定の高い電位まで電圧を印加したときに電解液が酸化分解して、電流増加率が急激に大きくなり、電流が流れ始める。 Linear sweep voltammetry (LSV) measurement was performed on a battery including the above electrolyte, platinum as a working electrode, and lithium metal as a counter electrode, and the current-potential curve formed by the measurement was expressed as Li + / It is preferable that the rising portion is shown at a potential of 4.5 V or more, more preferably 5.0 V or more with the Li electrode as a reference potential. It is considered that the electrolytic solution having such characteristics does not undergo oxidative decomposition at least up to a potential of 4.5V. LSV is an evaluation method for measuring the value of a current that flows when the potential of an electrode is continuously changed. By measuring the LSV of the non-aqueous secondary battery, a potential-current curve of the non-aqueous secondary battery is created. In the potential-current curve, the ratio of the increase amount of the current value to the increase amount of the potential is defined as the current increase rate. This increase rate is low immediately after voltage application. When a voltage is applied to a predetermined high potential, the electrolytic solution is oxidatively decomposed, the current increase rate increases rapidly, and current starts to flow.
　すなわち、ＬＳＶ評価を行うことにより形成された電流－電位曲線において、電圧印加直後から電位４．５Ｖ（ｖｓ　Ｌｉ＋／Ｌｉ）以上の高い所定の電位になるまでの間は、平坦部をもつ。電位が平坦部にあるときには、電解液は安定である。 In other words, the current-potential curve formed by performing the LSV evaluation has a flat portion from immediately after voltage application until a predetermined potential higher than 4.5 V (vs Li + / Li) is reached. When the potential is in the flat portion, the electrolytic solution is stable.
　電流－電位曲線において、所定の電位を超えたときに、電流増加率が急激に増加する立ち上がり部を示す。ここで、「立ち上がり部」は、電流－電位曲線において、平坦部よりも電流増加率が大きい部分をいう。立ち上がり部では、電解液が酸化分解して、電流が流れる。 In the current-potential curve, a rising portion where the current increase rate increases rapidly when a predetermined potential is exceeded is shown. Here, the “rising part” refers to a part of the current-potential curve that has a larger current increase rate than the flat part. At the rising portion, the electrolytic solution is oxidatively decomposed and a current flows.
　以下に、本発明の第１～第４の態様に係る電解液を用いた非水系二次電池を説明する。 Hereinafter, non-aqueous secondary batteries using the electrolytic solutions according to the first to fourth aspects of the present invention will be described.
　本発明の非水系二次電池は、リチウムイオンなどの金属イオンを吸蔵及び放出し得る正極活物質を有する正極と、リチウムイオンなどの金属イオンを吸蔵及び放出し得る負極活物質を有する負極と、金属塩を有する電解液とを備える。 The non-aqueous secondary battery of the present invention includes a positive electrode having a positive electrode active material capable of occluding and releasing metal ions such as lithium ions, and a negative electrode having a negative electrode active material capable of occluding and releasing metal ions such as lithium ions, And an electrolytic solution having a metal salt.
　非水系二次電池に用いられる正極は、金属イオンを吸蔵及び放出し得る正極活物質を有する。正極は、集電体と、集電体の表面に結着させた正極活物質層を有する。 The positive electrode used for a non-aqueous secondary battery has a positive electrode active material that can occlude and release metal ions. The positive electrode has a current collector and a positive electrode active material layer bound to the surface of the current collector.
　本発明の第１の態様において、正極活物質は、層状岩塩構造をもつリチウム金属複合酸化物を有する。層状岩塩構造をもつリチウム金属複合酸化物は、層状化合物ともいわれる。層状岩塩構造をもつリチウム金属複合酸化物は、一般式：ＬｉａＮｉｂＣｏｃＭｎｄＤｅＯｆ(０．２≦ａ≦１．２、ｂ＋ｃ＋ｄ＋ｅ＝１、０≦ｅ＜１、ＤはＬｉ、Ｆｅ、Ｃｒ、Ｃｕ、Ｚｎ、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ａｌ、Ｚｒ、Ｔｉ、Ｐ、Ｇａ、Ｇｅ、Ｖ、Ｍｏ、Ｎｂ、Ｗ、Ｌａ、Ｎｉ、Ｃｏから選ばれる少なくとも１の元素、１．７≦ｆ≦２．１)、Ｌｉ２ＭｎＯ３を挙げることができる。 In the first aspect of the present invention, the positive electrode active material has a lithium metal composite oxide having a layered rock salt structure. A lithium metal composite oxide having a layered rock salt structure is also referred to as a layered compound. The lithium metal composite oxide having a layered rock salt structure has a general formula: Li a Ni b Co c Mn d De O f (0.2 ≦ a ≦ 1.2, b + c + d + e = 1, 0 ≦ e <1, D is Li, Fe, Cr, Cu, Zn, Ca, Mg, S, Si, Na, K, Al, Zr, Ti, P, Ga, Ge, V, Mo, Nb, W, La, Ni, Co And at least one element, 1.7 ≦ f ≦ 2.1), and Li 2 MnO 3 .
　前記一般式の中のｂ：ｃ：ｄの比率は、０．５：０．２：０．３、１／３：１／３：１／３、０．７５：０．１０：０．１５、０：０：１、１：０：０、及び０：１：０から選ばれる少なくとも１種類であることが良い。 The ratio of b: c: d in the general formula is 0.5: 0.2: 0.3, 1/3: 1/3: 1/3, 0.75: 0.10: 0.15. 0: 0: 1, 1: 0: 0, and 0: 1: 0.
　即ち、層状岩塩構造をもつリチウム金属複合酸化物の具体例としては、ＬｉＮｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２、ＬｉＮｉ1/3Ｃｏ1/3Ｍｎ1/3Ｏ２、ＬｉＮｉ０．５Ｍｎ０．５Ｏ２、ＬｉＮｉ０．７５Ｃｏ０．１Ｍｎ０．１５Ｏ２、ＬｉＭｎＯ２、ＬｉＮｉＯ２、及びＬｉＣｏＯ２から選ばれる少なくとも一種であることがよい。 That is, specific examples of the lithium metal composite oxide having a layered rock salt structure include LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , LiNi 0. .5 Mn 0.5 O 2 , LiNi 0.75 Co 0.1 Mn 0.15 O 2 , LiMnO 2 , LiNiO 2 , and LiCoO 2 may be at least one kind.
　また、正極活物質は、層状岩塩構造をもつリチウム金属複合酸化物と、ＬｉＭｎ２Ｏ４、Ｌｉ２Ｍｎ２Ｏ４等のスピネルとの混合物で構成される固溶体を含んでいてもよく、例えば、Ｌｉ２ＭｎＯ３－ＬｉＣｏＯ２がある。 The positive electrode active material may include a solid solution composed of a mixture of a lithium metal composite oxide having a layered rock salt structure and spinel such as LiMn 2 O 4 and Li 2 Mn 2 O 4 . There is Li 2 MnO 3 —LiCoO 2 .
　正極活物質として用いられるいずれの金属酸化物も上記の組成式を基本組成とすればよく、基本組成に含まれる金属元素を他の金属元素で置換したものも使用可能であるし、Ｍｇなどの他の金属元素を基本組成のものに加えて金属酸化物としてもよい。 Any metal oxide used as the positive electrode active material may have the above composition formula as a basic composition, and a metal element included in the basic composition may be replaced with another metal element, and Mg, etc. Other metal elements may be added to the basic composition to form a metal oxide.
　本発明の第２の態様において、正極活物質は、スピネル構造を有するリチウム金属複合酸化物をもつ。スピネル構造を有するリチウム金属複合酸化物は、一般式：一般式：Ｌｉx(ＡyＭｎ2-y)Ｏ4（Ａは、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ａｌ、Ｐ、Ｇａ、Ｇｅから選ばれる少なくとも１の元素、及び遷移金属元素から選ばれる少なくとも１種の金属元素、０＜ｘ≦２．２、０＜ｙ≦１）で表されると良い。一般式の中のＡを構成し得る遷移金属元素は、例えば、Ｆｅ、Ｃｒ、Ｃｕ、Ｚｎ、Ｚｒ、Ｔｉ、Ｖ、Ｍｏ、Ｎｂ、Ｗ、Ｌａ、Ｎｉ、Ｃｏから選ばれる少なくとも１の元素であるとよい。 In the second aspect of the present invention, the positive electrode active material has a lithium metal composite oxide having a spinel structure. Lithium-metal composite oxide having a spinel structure of the general formula: the general formula: Li x (A y Mn 2 -y) O 4 (A is, Ca, Mg, S, Si , Na, K, Al, P, Ga And at least one element selected from Ge and at least one metal element selected from transition metal elements, 0 <x ≦ 2.2, 0 <y ≦ 1). The transition metal element that can constitute A in the general formula is, for example, at least one element selected from Fe, Cr, Cu, Zn, Zr, Ti, V, Mo, Nb, W, La, Ni, and Co. There should be.
　リチウム金属複合酸化物の具体例としては、ＬｉＭｎ２Ｏ４、ＬｉＮｉ０．５Ｍｎ１．５Ｏ４から選ばれる少なくとも一種であることがよい。 A specific example of the lithium metal composite oxide is preferably at least one selected from LiMn 2 O 4 and LiNi 0.5 Mn 1.5 O 4 .
　正極活物質として用いられるリチウム金属複合酸化物は、上記の組成式を基本組成とすればよく、基本組成に含まれる金属元素を他の金属元素で置換したものも使用可能であるし、Ｍｇなどの他の金属元素を基本組成のものに加えて金属酸化物としてもよい。 The lithium metal composite oxide used as the positive electrode active material only needs to have the above composition formula as a basic composition, and can be used in which the metal element contained in the basic composition is replaced with another metal element, such as Mg. Other metal elements may be added to the basic composition to form a metal oxide.
　本発明の第３の態様において、正極活物質は、ポリアニオン系材料をもつ。ポリアニオン系材料は、例えば、リチウムを含有するポリアニオン系材料であることがよい。リチウムを含有するポリアニオン系材料は、ＬｉＭＰＯ４、ＬｉＭＶＯ４又はＬｉ２ＭＳｉＯ４（式中のＭはＣｏ、Ｎｉ、Ｍｎ、Ｆｅのうちの少なくとも一種から選択される）などで表わされるポリアニオン系化合物を挙げることができる。 In the third aspect of the present invention, the positive electrode active material has a polyanionic material. The polyanion material may be, for example, a polyanion material containing lithium. The polyanionic material containing lithium is a polyanionic compound represented by LiMPO 4 , LiMVO 4 or Li 2 MSiO 4 (wherein M is selected from at least one of Co, Ni, Mn, and Fe). Can be mentioned.
　ポリアニオン系材料の具体例としては、オリビン構造をもつＬｉＦｅＰＯ４、Ｌｉ２ＦｅＳｉＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４、Ｌｉ２ＭｎＰＯ４、Ｌｉ２ＭｎＳｉＯ４から選ばれる少なくとも一種であることがよい。 Specific examples of the polyanion-based material may be at least one selected from LiFePO 4 , Li 2 FeSiO 4 , LiCoPO 4 , Li 2 CoPO 4 , Li 2 MnPO 4 , and Li 2 MnSiO 4 having an olivine structure.
　正極活物質として用いられるポリアニオン系材料は、上記の組成式を基本組成とすればよく、基本組成に含まれる金属元素を他の金属元素で置換したものも使用可能であるし、Ｍｇなどの他の金属元素を基本組成のものに加えて金属酸化物としてもよい。 The polyanion-based material used as the positive electrode active material may have the above composition formula as a basic composition, and a material obtained by substituting a metal element included in the basic composition with another metal element can be used. These metal elements may be added to the basic composition to form a metal oxide.
　本発明の第４の態様において、正極活物質は、リチウム金属複合酸化物、及び／又はポリアニオン系材料をもつとよい。 In the fourth aspect of the present invention, the positive electrode active material may have a lithium metal composite oxide and / or a polyanion material.
　このリチウム金属複合酸化物は、スピネル構造を有することがよい。スピネル構造を有するリチウム金属複合酸化物は、一般式：Ｌｉｘ(ＡｙＭｎ２-ｙ)Ｏ4（Ａは、遷移金属元素、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ａｌ、Ｐ、Ｇａ、及びＧｅから選ばれる少なくとも１種の元素、０＜ｘ≦２．２、０＜ｙ≦１）で表わされると良い。一般式の中のＡを構成し得る遷移金属元素は、例えば、Ｆｅ、Ｃｒ、Ｃｕ、Ｚｎ、Ｚｒ、Ｔｉ、Ｖ、Ｍｏ、Ｎｂ、Ｗ、Ｌａ、Ｎｉ、Ｃｏから選ばれる少なくとも１の元素であるとよい。リチウム金属複合酸化物の具体例としては、ＬｉＭｎ２Ｏ４及びＬｉＮｉ０．５Ｍｎ１．５Ｏ４の群から選ばれる少なくとも一種であることがよい。 The lithium metal composite oxide preferably has a spinel structure. Lithium-metal composite oxide having a spinel structure represented by the general formula: Li x (A y Mn 2 -y) is O 4 (A, transition metal elements, Ca, Mg, S, Si , Na, K, Al, P, It may be represented by at least one element selected from Ga and Ge, 0 <x ≦ 2.2, 0 <y ≦ 1). The transition metal element that can constitute A in the general formula is, for example, at least one element selected from Fe, Cr, Cu, Zn, Zr, Ti, V, Mo, Nb, W, La, Ni, and Co. There should be. A specific example of the lithium metal composite oxide is preferably at least one selected from the group consisting of LiMn 2 O 4 and LiNi 0.5 Mn 1.5 O 4 .
　リチウム金属複合酸化物は、スピネル構造をもつものとともに、又はスピネル構造をもつものの代わりに、層状岩塩構造をもつものであってもよい。層状岩塩構造をもつリチウム金属複合酸化物は、層状化合物ともいわれる。層状岩塩構造をもつリチウム金属複合酸化物は、一般式：ＬｉａＮｉｂＣｏｃＭｎｄＤｅＯｆ(０．２≦ａ≦１．２、ｂ＋ｃ＋ｄ＋ｅ＝１、０≦ｅ＜１、ＤはＬｉ、Ｆｅ、Ｃｒ、Ｃｕ、Ｚｎ、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ａｌ、Ｚｒ、Ｔｉ、Ｐ、Ｇａ、Ｇｅ、Ｖ、Ｍｏ、Ｎｂ、Ｗ、Ｌａ、Ｎｉ、Ｃｏから選ばれる少なくとも１の元素、１．７≦ｆ≦２．１)、Ｌｉ２ＭｎＯ３を挙げることができる。 The lithium metal composite oxide may have a layered rock salt structure together with the spinel structure or instead of the spinel structure. A lithium metal composite oxide having a layered rock salt structure is also referred to as a layered compound. The lithium metal composite oxide having a layered rock salt structure has a general formula: Li a Ni b Co c Mn d De O f (0.2 ≦ a ≦ 1.2, b + c + d + e = 1, 0 ≦ e <1, D is Li, Fe, Cr, Cu, Zn, Ca, Mg, S, Si, Na, K, Al, Zr, Ti, P, Ga, Ge, V, Mo, Nb, W, La, Ni, Co And at least one element, 1.7 ≦ f ≦ 2.1), and Li 2 MnO 3 .
　また、リチウム金属複合酸化物は、層状岩塩構造をもつものと、ＬｉＭｎ２Ｏ４、ＬｉＮi０．５Ｍｎ１．５Ｏ４等のスピネルとの混合物で構成される固溶体を含んでいてもよい。 The lithium metal composite oxide may contain a solid solution composed of a mixture of a layered rock salt structure and a spinel such as LiMn 2 O 4 or LiNi 0.5 Mn 1.5 O 4 .
　ポリアニオン系材料は、例えば、リチウムを含有するポリアニオン系材料であることがよい。リチウムを含有するポリアニオン系材料は、ＬｉＭＰＯ４、ＬｉＭＶＯ４又はＬｉ２ＭＳｉＯ４（式中のＭはＣｏ、Ｎｉ、Ｍｎ、Ｆｅのうちの少なくとも一種から選択される）などで表わされるポリアニオン系化合物を挙げることができる。 The polyanion material may be, for example, a polyanion material containing lithium. The polyanionic material containing lithium is a polyanionic compound represented by LiMPO 4 , LiMVO 4 or Li 2 MSiO 4 (wherein M is selected from at least one of Co, Ni, Mn, and Fe). Can be mentioned.
　これら正極活物質の中で、リチウム金属複合酸化物及び/又はポリアニオン系材料は、Ｌｉ＋／Ｌｉ電極基準で４．５Ｖ以上の反応電位をもつことが好ましい。ここで、「正極活物質の反応電位」とは、充電により正極活物質が還元反応を生じる電位をいう。この反応電位は、Ｌｉ＋／Ｌｉ電極基準とする。反応電位には、多少幅がある場合があるが、本明細書において「反応電位」は幅がある反応電位の中の平均値をいう。反応電位が複数段ある場合には、複数段の反応電位の中の平均値をいう。反応電位がＬｉ＋／Ｌｉ電極基準で４．５Ｖ以上であるリチウム金属複合酸化物及びポリアニオン系材料は、例えば、ＬｉＮｉ０．５Ｍｎ１．５Ｏ４（スピネル）、ＬｉＣｏＰＯ４（ポリアニオン）、Ｌｉ２ＣｏＰＯ４Ｆ（ポリアニオン）、Ｌｉ２ＭｎＯ３－ＬｉＭＯ２（式中のＭはＣｏ、Ｎｉ、Ｍｎ、Ｆｅのうちの少なくとも一種から選択される）（層状岩塩構造をもつ固溶体系）、Ｌｉ２ＭｎＳｉＯ４（ポリアニオン）などが挙げられるが、これに限定されない。 Among these positive electrode active materials, the lithium metal composite oxide and / or the polyanion-based material preferably has a reaction potential of 4.5 V or more on the basis of the Li + / Li electrode. Here, the “reaction potential of the positive electrode active material” refers to a potential at which the positive electrode active material undergoes a reduction reaction upon charging. This reaction potential is based on the Li + / Li electrode. Although the reaction potential may vary somewhat, in this specification, “reaction potential” refers to an average value of reaction potentials having a width. When there are a plurality of reaction potentials, it means an average value among the reaction potentials of the plurality of stages. Examples of the lithium metal composite oxide and polyanion-based material having a reaction potential of 4.5 V or more on the basis of the Li + / Li electrode include LiNi 0.5 Mn 1.5 O 4 (spinel), LiCoPO 4 (polyanion), Li 2 CoPO 4 F (polyanion), Li 2 MnO 3 —LiMO 2 (wherein M is selected from at least one of Co, Ni, Mn, and Fe) (solid solution system having a layered rock salt structure), Li 2 such MnSiO 4 (polyanion) include, but are not limited thereto.
　また、リチウム金属複合酸化物及びポリアニオン系材料は、Ｌｉ＋／Ｌｉ電極基準で４．５Ｖ未満の反応電位をもっていてもよい。このようなリチウム金属複合酸化物としては、例えば、層状岩塩構造をもつものの中では、ＬｉＮｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２、ＬｉＮｉ1/3Ｃｏ1/3Ｍｎ1/3Ｏ２、ＬｉＮｉ０．５Ｍｎ０．５Ｏ２、ＬｉＮｉ０．７５Ｃｏ０．１Ｍｎ０．１５Ｏ２、ＬｉＭｎＯ２、ＬｉＮｉＯ２、及びＬｉＣｏＯ２から選ばれる少なくとも一種が挙げられる。ポリアニオン系材料の中では、オリビン構造をもつＬｉＦｅＰＯ４、及びＬｉ２ＦｅＳｉＯ４から選ばれる少なくとも一種のものが挙げられるが、これに限定されない。 Further, the lithium metal composite oxide and the polyanion material may have a reaction potential of less than 4.5 V on the basis of the Li + / Li electrode. As such a lithium metal complex oxide, for example, among those having a layered rock salt structure, LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , at least one selected from LiNi 0.5 Mn 0.5 O 2 , LiNi 0.75 Co 0.1 Mn 0.15 O 2 , LiMnO 2 , LiNiO 2 , and LiCoO 2 . Examples of the polyanionic material include at least one selected from LiFePO 4 having an olivine structure and Li 2 FeSiO 4 , but are not limited thereto.
　上記の正極活物質及び、それらを用いた電池を表３に示すタイプに分類して特徴を説明する。 The above-described positive electrode active materials and batteries using them are classified into the types shown in Table 3 and their characteristics will be described.
　図９２は、リチウム金属複合酸化物及びポリアニオン系材料の充電曲線のモデル説明図を示す。図９２に示すように、リチウム金属複合酸化物は、固溶体型と二相共存型とがある。固溶体型は、活物質の反応が固溶体を経由する場合で、放電が進むとともに正極電位が徐々に低下し、充電が進むとともに電位が徐々に上昇する。二相共存型は、活物質が放電すると第二の相が現れて二相が共存し、放電が進んでも正極電位が低下しない領域があり、充電が進んだ場合にも電位が上昇しない領域がある。 FIG. 92 shows a model explanatory diagram of a charging curve of a lithium metal composite oxide and a polyanion material. As shown in FIG. 92, the lithium metal composite oxide has a solid solution type and a two-phase coexistence type. The solid solution type is a case where the reaction of the active material passes through the solid solution, and as the discharge proceeds, the positive electrode potential gradually decreases, and as the charging proceeds, the potential gradually increases. In the two-phase coexistence type, when the active material is discharged, the second phase appears, the two phases coexist, there is a region where the positive electrode potential does not decrease even if the discharge proceeds, and there is a region where the potential does not increase even when the charging proceeds. is there.
　固溶体型の４Ｖ級活物質（ＬｉＣｏＯ２など）を使った電池で、最高使用電位を５Ｖにすると、平均セル電圧及び容量が若干向上する。ただし、一般的には活物質自体も高電位にしたことで劣化する場合がある。 In a battery using a solid solution type 4V class active material (LiCoO 2 or the like), when the maximum use potential is 5 V, the average cell voltage and capacity are slightly improved. However, in general, the active material itself may deteriorate due to the high potential.
　二相共存型の４Ｖ級活物質（ＬＭｎ２Ｏ４など）を使った電池で、最高使用電位を５Ｖにすると、平均セル電圧及び容量はほとんど変わらない。ただし、一般的に活物質自体の高電位耐性は高いので、最高使用電位を５Ｖまで上げることができる。 In a battery using a two-phase coexistence type 4V class active material (LMn 2 O 4 or the like), when the maximum use potential is 5 V, the average cell voltage and capacity are hardly changed. However, since the high potential resistance of the active material itself is generally high, the maximum usable potential can be increased to 5V.
　二相共存型の５Ｖ級活物質（ＬｉＮｉ０．５Ｍｎ１．５Ｏ４など）を使った電池では、最高使用電位を４Ｖにすると容量はでないが、５Ｖにすると容量が出現する。 In a battery using a two-phase coexisting type 5V class active material (LiNi 0.5 Mn 1.5 O 4 or the like), the capacity does not appear when the maximum use potential is 4 V, but the capacity appears when 5 V is used.
　これら性質を加味して上記正極と本発明の電解液とを自由に組み合わせてよい。 Considering these properties, the positive electrode and the electrolytic solution of the present invention may be freely combined.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　正極活物質として用いられるリチウム金属複合酸化物は、上記の組成式を基本組成とすればよく、基本組成に含まれる金属元素を他の金属元素で置換したものも使用可能であるし、Ｍｇなどの他の金属元素を基本組成のものに加えて金属酸化物としてもよい。 The lithium metal composite oxide used as the positive electrode active material only needs to have the above composition formula as a basic composition, and can be used in which the metal element contained in the basic composition is replaced with another metal element, such as Mg. Other metal elements may be added to the basic composition to form a metal oxide.
　以上をふまえると、本発明の非水系二次電池は、正極活物質として上記リチウム金属複合酸化物又は上記ポリアニオン系材料を有する正極と、負極活物質を有する負極と、電解液とを有する非水系二次電池であって、前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする非水系二次電池と把握することができる。 Based on the above, the non-aqueous secondary battery of the present invention is a non-aqueous battery having a positive electrode having the lithium metal composite oxide or the polyanionic material as a positive electrode active material, a negative electrode having a negative electrode active material, and an electrolyte. A secondary battery, wherein the electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal, or aluminum and an organic solvent having a hetero element, and the organic solvent in a vibrational spectrum of the electrolytic solution Assuming that the intensity of the peak derived from the organic solvent is Io and the intensity of the peak shifted from the peak is Is, it is understood that the nonaqueous secondary battery is Is> Io. be able to.
　本発明の第１～第４の態様において、正極の集電体は、使用する活物質に適した電圧に耐え得る金属であれば特に制限はない。集電体は、非水系二次電池の放電又は充電の間、電極に電流を流し続けるための化学的に不活性な電子高伝導体をいう。集電体としては、銀、銅、金、アルミニウム、タングステン、コバルト、亜鉛、ニッケル、鉄、白金、錫、インジウム、チタン、ルテニウム、タンタル、クロム、モリブデンから選ばれる少なくとも一種、並びにステンレス鋼などの金属材料を例示することができる。 In the first to fourth embodiments of the present invention, the positive electrode current collector is not particularly limited as long as it is a metal that can withstand a voltage suitable for the active material to be used. The current collector refers to a chemically inert electronic high conductor that keeps a current flowing through an electrode during discharging or charging of a non-aqueous secondary battery. As the current collector, at least one selected from silver, copper, gold, aluminum, tungsten, cobalt, zinc, nickel, iron, platinum, tin, indium, titanium, ruthenium, tantalum, chromium, molybdenum, and stainless steel, etc. Metal materials can be exemplified.
　具体的には、正極用集電体として、アルミニウムまたはアルミニウム合金からなるものを用いるのが好ましい。ここでアルミニウムは、純アルミニウムを指し、純度９９．０％以上のアルミニウムを純アルミニウムと称する。純アルミニウムに種々の元素を添加して合金としたものをアルミニウム合金と称する。アルミニウム合金としては、Ａｌ－Ｃｕ系、Ａｌ－Ｍｎ系、Ａｌ－Ｆｅ系、Ａｌ－Ｓｉ系、Ａｌ－Ｍｇ系、ＡＬ－Ｍｇ－Ｓｉ系、Ａｌ－Ｚｎ－Ｍｇ系が挙げられる。 Specifically, the positive electrode current collector is preferably made of aluminum or an aluminum alloy. Here, aluminum refers to pure aluminum, and aluminum having a purity of 99.0% or more is referred to as pure aluminum. An alloy obtained by adding various elements to pure aluminum is referred to as an aluminum alloy. Examples of the aluminum alloy include Al—Cu, Al—Mn, Al—Fe, Al—Si, Al—Mg, AL—Mg—Si, and Al—Zn—Mg.
　また、アルミニウムまたはアルミニウム合金として、具体的には、例えばＪＩＳ　Ａ１０８５、Ａ１Ｎ３０等のＡ１０００系合金（純アルミニウム系)、ＪＩＳ　Ａ３００３、Ａ３００４等のＡ３０００系合金（Ａｌ－Ｍｎ系）、ＪＩＳ　Ａ８０７９、Ａ８０２１等のＡ８０００系合金（Ａｌ－Ｆｅ系）が挙げられる。 Specific examples of aluminum or aluminum alloy include, for example, A1000 series alloys (pure aluminum series) such as JIS A1085 and A1N30, A3000 series alloys (Al-Mn series) such as JIS A3003 and A3004, JIS A8079, A8021, etc. A8000-based alloy (Al-Fe-based).
　正極の電位をリチウム基準で４Ｖ以上とする場合には、集電体としてアルミニウムを採用するのが好ましい。集電体は公知の保護層で被覆されていても良い。集電体の表面を公知の方法で処理したものを集電体として用いても良い。 When the potential of the positive electrode is 4 V or higher with respect to lithium, it is preferable to employ aluminum as the current collector. The current collector may be covered with a known protective layer. What collected the surface of the electrical power collector by the well-known method may be used as an electrical power collector.
　集電体は箔、シート、フィルム、線状、棒状、メッシュなどの形態をとることができる。そのため、集電体として、例えば、銅箔、ニッケル箔、アルミニウム箔、ステンレス箔などの金属箔を好適に用いることができる。集電体が箔、シート、フィルム形態の場合は、その厚みが１μｍ～１００μｍの範囲内であることが好ましい。 The current collector can take the form of a foil, a sheet, a film, a linear shape, a rod shape, a mesh, or the like. Therefore, for example, a metal foil such as a copper foil, a nickel foil, an aluminum foil, and a stainless steel foil can be suitably used as the current collector. When the current collector is in the form of foil, sheet or film, the thickness is preferably in the range of 1 μm to 100 μm.
　正極活物質層は正極活物質、並びに必要に応じて結着剤及び／又は導電助剤を含む。 The positive electrode active material layer contains a positive electrode active material and, if necessary, a binder and / or a conductive aid.
　結着剤は活物質及び導電助剤を集電体の表面に繋ぎ止める役割を果たすものである。 The binder plays a role of connecting the active material and the conductive auxiliary agent to the surface of the current collector.
　結着剤としては、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、フッ素ゴム等の含フッ素樹脂、ポリプロピレン、ポリエチレン等の熱可塑性樹脂、ポリイミド、ポリアミドイミド等のイミド系樹脂、アルコキシシリル基含有樹脂を例示することができる。 Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, and alkoxysilyl group-containing resins. be able to.
　また、結着剤として、親水基を有するポリマーを採用してもよい。親水基を有するポリマーの親水基としては、カルボキシル基、スルホ基、シラノール基、アミノ基、水酸基、リン酸基などリン酸系の基などが例示される。中でも、ポリアクリル酸(PAA)、カルボキシメチルセルロース(CMC)、ポリメタクリル酸など、分子中にカルボキシル基を含むポリマー、又は、ポリ（ｐ－スチレンスルホン酸）などのスルホ基を含むポリマーが好ましい。 Also, a polymer having a hydrophilic group may be employed as the binder. Examples of the hydrophilic group of the polymer having a hydrophilic group include a phosphate group such as a carboxyl group, a sulfo group, a silanol group, an amino group, a hydroxyl group, and a phosphate group. Among them, a polymer containing a carboxyl group in the molecule such as polyacrylic acid (PAA), carboxymethyl cellulose (CMC) and polymethacrylic acid, or a polymer containing a sulfo group such as poly (p-styrenesulfonic acid) is preferable.
　ポリアクリル酸、あるいはアクリル酸とビニルスルホン酸との共重合体など、カルボキシル基及び／又はスルホ基を多く含むポリマーは水溶性となる。したがって親水基を有するポリマーは、水溶性ポリマーであることが好ましく、一分子中に複数のカルボキシル基及び／又はスルホ基を含むポリマーが好ましい。 Polymers containing a large amount of carboxyl groups and / or sulfo groups, such as polyacrylic acid or a copolymer of acrylic acid and vinyl sulfonic acid, are water-soluble. Therefore, the polymer having a hydrophilic group is preferably a water-soluble polymer, and a polymer containing a plurality of carboxyl groups and / or sulfo groups in one molecule is preferable.
　分子中にカルボキシル基を含むポリマーは、例えば、酸モノマーを重合する、あるいはポリマーにカルボキシル基を付与する、などの方法で製造することができる。酸モノマーとしては、アクリル酸、メタクリル酸、ビニル安息香酸、クロトン酸、ペンテン酸、アンジェリカ酸、チグリン酸など分子中に一つのカルボキシル基をもつ酸モノマー、イタコン酸、メサコン酸、シトラコン酸、フマル酸、マレイン酸、２－ペンテン二酸、メチレンコハク酸、アリルマロン酸、イソプロピリデンコハク酸、２，４－ヘキサジエン二酸、アセチレンジカルボン酸など分子内に二つ以上のカルボキシル基をもつ酸モノマーなどが例示される。これらから選ばれる二種以上のモノマーを重合してなる共重合ポリマーを用いてもよい。 The polymer containing a carboxyl group in the molecule can be produced by, for example, a method of polymerizing an acid monomer or adding a carboxyl group to the polymer. Acid monomers include acrylic acid, methacrylic acid, vinyl benzoic acid, crotonic acid, pentenoic acid, angelic acid, tiglic acid, etc., acid monomers having one carboxyl group in the molecule, itaconic acid, mesaconic acid, citraconic acid, fumaric acid Examples include maleic acid, 2-pentenedioic acid, methylene succinic acid, allyl malonic acid, isopropylidene succinic acid, 2,4-hexadiene diacid, acetylenedicarboxylic acid, and other acid monomers having two or more carboxyl groups in the molecule. Is done. A copolymer obtained by polymerizing two or more kinds of monomers selected from these may be used.
　例えば特開2013-065493号公報に記載されたような、アクリル酸とイタコン酸との共重合体からなり、カルボキシル基どうしが縮合して形成された酸無水物基を分子中に含んでいるポリマーを結着剤として用いることも好ましい。一分子中にカルボキシル基を二つ以上有する酸性度の高いモノマー由来の構造があることにより、充電時に電解液分解反応が起こる前にリチウムイオンなどの金属イオンをトラップし易くなると考えられている。さらに、ポリアクリル酸やポリメタクリル酸に比べてカルボキシル基が多く酸性度が高まると共に、所定量のカルボキシル基が酸無水物基に変化しているため、酸性度が高まりすぎることもない。そのため、この結着剤を用いて形成された負極をもつ二次電池は、初期効率が向上し、入出力特性が向上する。 For example, a polymer composed of a copolymer of acrylic acid and itaconic acid as described in JP-A-2013-065493, and containing an acid anhydride group formed by condensation of carboxyl groups in the molecule It is also preferable to use as a binder. The structure derived from a highly acidic monomer having two or more carboxyl groups in one molecule is believed to facilitate trapping of metal ions such as lithium ions before the electrolytic solution decomposition reaction occurs during charging. Furthermore, the acidity is not excessively increased because there are more carboxyl groups and the acidity is higher than polyacrylic acid and polymethacrylic acid, and a predetermined amount of the carboxyl groups are changed to acid anhydride groups. Therefore, a secondary battery having a negative electrode formed using this binder has improved initial efficiency and improved input / output characteristics.
　正極活物質層中の結着剤の配合割合は、質量比で、正極活物質：結着剤＝１：０．００５～１：０．５であるのがよく、更に、正極活物質：結着剤＝１：０．００５～１：０．３であることが好ましい。結着剤が少なすぎると電極の成形性が低下し、また、結着剤が多すぎると電極のエネルギー密度が低くなるためである。 The mixing ratio of the binder in the positive electrode active material layer is preferably a positive electrode active material: binder = 1: 0.005 to 1: 0.5 in terms of mass ratio. Adhesive = 1: 0.005 to 1: 0.3 is preferable. This is because when the amount of the binder is too small, the moldability of the electrode is lowered, and when the amount of the binder is too large, the energy density of the electrode is lowered.
　導電助剤は、電極の導電性を高めるために添加される。そのため、導電助剤は、電極の導電性が不足する場合に任意に加えればよく、電極の導電性が十分に優れている場合には加えなくても良い。導電助剤としては化学的に不活性な電子高伝導体であれば良く、炭素質微粒子であるカーボンブラック、黒鉛、アセチレンブラック、ケッチェンブラック（登録商標）、気相法炭素繊維（Vapor Grown Carbon Fiber：ＶＧＣＦ）、および各種金属粒子などが例示される。これらの導電助剤を単独または二種以上組み合わせて活物質層に添加することができる。 Conductive aid is added to increase the conductivity of the electrode. Therefore, the conductive auxiliary agent may be added arbitrarily when the electrode conductivity is insufficient, and may not be added when the electrode conductivity is sufficiently excellent. The conductive auxiliary agent may be any chemically inert electronic high conductor, such as carbon black, graphite, acetylene black, ketjen black (registered trademark), or vapor grown carbon fiber (Vapor Grown Carbon). Fiber: VGCF) and various metal particles are exemplified. These conductive assistants can be added to the active material layer alone or in combination of two or more.
　正極活物質層中の結着剤の配合割合は、質量比で、正極活物質：結着剤＝１：０．０５～１：０．５であるのが好ましい。結着剤が少なすぎると電極の成形性が低下し、また、結着剤が多すぎると電極のエネルギー密度が低くなるためである。 The blending ratio of the binder in the positive electrode active material layer is preferably a positive electrode active material: binder = 1: 0.05 to 1: 0.5 in mass ratio. This is because when the amount of the binder is too small, the moldability of the electrode is lowered, and when the amount of the binder is too large, the energy density of the electrode is lowered.
　本発明の非水系二次電池に用いられる負極は、集電体と、集電体の表面に結着させた負極活物質層を有する。負極活物質層は負極活物質、並びに必要に応じて結着剤及び／又は導電助剤を含む。負極活物質層に含まれることがある結着剤及び導電助剤は、正極活物質層に含まれることがある結着剤及び導電助剤と同様の成分及び組成比とすることができる。 The negative electrode used in the non-aqueous secondary battery of the present invention has a current collector and a negative electrode active material layer bound to the surface of the current collector. The negative electrode active material layer includes a negative electrode active material and, if necessary, a binder and / or a conductive aid. The binder and conductive additive that may be contained in the negative electrode active material layer may have the same components and composition ratios as the binder and conductive aid that may be contained in the positive electrode active material layer.
　負極活物質としては、リチウムイオンなどの金属イオンを吸蔵及び放出し得る材料が使用可能である。したがって、リチウムイオンなどの金属イオンを吸蔵及び放出可能である単体、合金または化合物であれば特に限定はない。たとえば、負極活物質としてＬｉや、炭素、ケイ素、ゲルマニウム、錫などの１４族元素、アルミニウム、インジウムなどの１３族元素、亜鉛、カドミウムなどの１２族元素、アンチモン、ビスマスなどの１５族元素、マグネシウム、カルシウムなどのアルカリ土類金属、銀、金などの１１族元素をそれぞれ単体で採用すればよい。ケイ素などを負極活物質に採用すると、ケイ素１原子が複数のリチウムと反応するため、高容量の活物質となるが、リチウムの吸蔵及び放出に伴う体積の膨張及び収縮が顕著となるとの問題が生じる恐れがあるため、当該恐れの軽減のために、ケイ素などの単体に遷移金属などの他の元素を組み合わせた合金又は化合物を負極活物質として採用するのも好適である。合金又は化合物の具体例としては、Ａｇ－Ｓｎ合金、Ｃｕ－Ｓｎ合金、Ｃｏ－Ｓｎ合金等の錫系材料、各種黒鉛などの炭素系材料、ケイ素単体と二酸化ケイ素に不均化するＳｉＯｘ（０．３≦ｘ≦１．６）などのケイ素系材料、ケイ素単体若しくはケイ素系材料と炭素系材料を組み合わせた複合体が挙げられる。また、負極活物質して、Ｎｂ２Ｏ５、ＴｉＯ２、Ｌｉ４Ｔｉ５Ｏ１２、ＷＯ２、ＭｏＯ２、Ｆｅ２Ｏ３等の酸化物、又は、Ｌｉ３－ｘＭｘＮ（Ｍ＝Ｃｏ、Ｎｉ、Ｃｕ）で表される窒化物を採用しても良い。負極活物質として、これらのものの一種以上を使用することができる。なお、本明細書において、リチウムイオンを吸蔵及び放出し得る材料を負極活物質および正極活物質として使用している非水系二次電池を、リチウムイオン二次電池という。 As the negative electrode active material, a material that can occlude and release metal ions such as lithium ions can be used. Therefore, there is no particular limitation as long as it is a simple substance, alloy, or compound that can occlude and release metal ions such as lithium ions. For example, as a negative electrode active material, Li, group 14 elements such as carbon, silicon, germanium and tin, group 13 elements such as aluminum and indium, group 12 elements such as zinc and cadmium, group 15 elements such as antimony and bismuth, magnesium , Alkaline earth metals such as calcium, and group 11 elements such as silver and gold may be employed alone. When silicon or the like is used for the negative electrode active material, a silicon atom reacts with a plurality of lithiums, so that it becomes a high-capacity active material. However, there is a problem that volume expansion and contraction due to insertion and extraction of lithium becomes significant. In order to reduce the fear, it is also preferable to employ an alloy or compound in which another element such as a transition metal is combined with a simple substance such as silicon as the negative electrode active material. Specific examples of the alloy or compound include tin-based materials such as Ag—Sn alloy, Cu—Sn alloy and Co—Sn alloy, carbon-based materials such as various graphites, SiO x (disproportionated into silicon simple substance and silicon dioxide). Examples thereof include silicon-based materials such as 0.3 ≦ x ≦ 1.6), silicon alone, or composites obtained by combining silicon-based materials and carbon-based materials. Further, as the negative electrode active material, oxides such as Nb 2 O 5 , TiO 2 , Li 4 Ti 5 O 12 , WO 2 , MoO 2 , Fe 2 O 3 , or Li 3-x M x N (M = A nitride represented by (Co, Ni, Cu) may be employed. One or more of these materials can be used as the negative electrode active material. Note that in this specification, a non-aqueous secondary battery using a material capable of inserting and extracting lithium ions as a negative electrode active material and a positive electrode active material is referred to as a lithium ion secondary battery.
　負極の集電体は、使用する活物質に適した電圧に耐え得る金属であれば特に制限はなく、例えば、正極の集電体で説明したものを採用できる。負極の結着剤および導電助剤は正極で説明したものを採用できる。 The negative electrode current collector is not particularly limited as long as it is a metal that can withstand a voltage suitable for the active material to be used, and for example, the one described for the positive electrode current collector can be adopted. As the negative electrode binder and the conductive additive, those described for the positive electrode can be adopted.
　集電体の表面に活物質層を形成させる方法には、ロールコート法、ダイコート法、ディップコート法、ドクターブレード法、スプレーコート法、カーテンコート法などの従来から公知の方法を用いて、集電体の表面に活物質を塗布すればよい。具体的には、活物質、並びに必要に応じて結着剤及び導電助剤を含む活物質層形成用組成物を調製し、この組成物に適当な溶剤を加えてペースト状にしてから、集電体の表面に塗布後、乾燥する。溶剤としては、Ｎ－メチル－２－ピロリドン、メタノール、メチルイソブチルケトン、水を例示できる。電極密度を高めるべく、乾燥後のものを圧縮しても良い。 As a method for forming the active material layer on the surface of the current collector, a conventionally known method such as a roll coating method, a die coating method, a dip coating method, a doctor blade method, a spray coating method, or a curtain coating method is used. An active material may be applied to the surface of the electric body. Specifically, an active material layer-forming composition containing an active material and, if necessary, a binder and a conductive aid is prepared, and an appropriate solvent is added to the composition to make a paste, and then the collection is performed. After applying to the surface of the electric body, it is dried. Examples of the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, and water. In order to increase the electrode density, the dried product may be compressed.
　非水系二次電池には必要に応じてセパレータが用いられる。セパレータは、正極と負極とを隔離し、両極の接触による電流の短絡を防止しつつ、リチウムイオンなどの金属イオンを通過させるものである。セパレータとしては、ポリテトラフルオロエチレン、ポリプロピレン、ポリエチレン、ポリイミド、ポリアミド、ポリアラミド（Ａｒｏｍａｔｉｃ　ｐｏｌｙａｍｉｄｅ）、ポリエステル、ポリアクリロニトリル等の合成樹脂、セルロース、アミロース等の多糖類、フィブロイン、ケラチン、リグニン、スベリン等の天然高分子、セラミックスなどの電気絶縁性材料を１種若しくは複数用いた多孔体、不織布、織布などを挙げることができる。また、セパレータは多層構造としてもよい。電解液は粘度がやや高く極性が高いため、水などの極性溶媒が浸み込みやすい膜が好ましい。具体的には、存在する空隙の９０％以上に水などの極性溶媒が浸み込む膜がさらに好ましい。 A separator is used for non-aqueous secondary batteries as necessary. The separator separates the positive electrode and the negative electrode and allows metal ions such as lithium ions to pass while preventing a short circuit of current due to contact between the two electrodes. As separators, natural resins such as polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamide, polyaramid (Aromatic polymer), polyester, polyacrylonitrile, etc., polysaccharides such as cellulose, amylose, fibroin, keratin, lignin, suberin, etc. Examples thereof include porous bodies, nonwoven fabrics, and woven fabrics using one or more electrically insulating materials such as polymers and ceramics. The separator may have a multilayer structure. Since the electrolytic solution has a slightly high viscosity and a high polarity, a membrane in which a polar solvent such as water can easily penetrate is preferable. Specifically, a film in which a polar solvent such as water soaks into 90% or more of the existing voids is more preferable.
　正極および負極に必要に応じてセパレータを挟装させ電極体とする。電極体は、正極、セパレータ及び負極を重ねた積層型、又は、正極、セパレータ及び負極を捲いた捲回型のいずれの型にしても良い。正極の集電体および負極の集電体から外部に通ずる正極端子および負極端子までの間を、集電用リード等を用いて接続した後に、電極体に電解液を加えて非水系二次電池とするとよい。また、本発明の非水系二次電池は、電極に含まれる活物質の種類に適した電圧範囲で充放電を実行されればよい。 A separator is sandwiched between the positive electrode and the negative electrode as necessary to form an electrode body. The electrode body may be either a stacked type in which the positive electrode, the separator and the negative electrode are stacked, or a wound type in which the positive electrode, the separator and the negative electrode are sandwiched. After connecting between the positive electrode current collector and the negative electrode current collector to the positive electrode terminal and the negative electrode terminal connected to the outside using a current collecting lead or the like, an electrolyte is added to the electrode body to add a non-aqueous secondary battery It is good to do. Moreover, the non-aqueous secondary battery of this invention should just be charged / discharged in the voltage range suitable for the kind of active material contained in an electrode.
　本発明の非水系二次電池の形状は特に限定されるものでなく、円筒型、角型、コイン型、ラミネート型等、種々の形状を採用することができる。 The shape of the non-aqueous secondary battery of the present invention is not particularly limited, and various shapes such as a cylindrical shape, a square shape, a coin shape, and a laminate shape can be adopted.
　本発明の非水系二次電池は、車両に搭載してもよい。車両は、その動力源の全部あるいは一部に非水系二次電池による電気エネルギーを使用している車両であればよく、たとえば、電気車両、ハイブリッド車両などであるとよい。車両に非水系二次電池を搭載する場合には、非水系二次電池を複数直列に接続して組電池とするとよい。非水系二次電池は、車両以外にも、パーソナルコンピュータ、携帯通信機器など、電池で駆動される各種の家電製品、オフィス機器、産業機器などが挙げられる。さらに、本発明の非水系二次電池は、風力発電、太陽光発電、水力発電その他電力系統の蓄電装置及び電力平滑化装置、船舶等の動力及び／又は補機類の電力供給源、航空機、宇宙船等の動力及び／又は補機類の電力供給源、電気を動力源に用いない車両の補助用電源、移動式の家庭用ロボットの電源、システムバックアップ用電源、無停電電源装置の電源、電動車両用充電ステーションなどにおいて充電に必要な電力を一時蓄える蓄電装置に用いてもよい。 The non-aqueous secondary battery of the present invention may be mounted on a vehicle. The vehicle may be a vehicle that uses electric energy from a non-aqueous secondary battery for all or a part of its power source. For example, the vehicle may be an electric vehicle or a hybrid vehicle. When a non-aqueous secondary battery is mounted on a vehicle, a plurality of non-aqueous secondary batteries may be connected in series to form an assembled battery. Examples of the non-aqueous secondary battery include various home electric appliances, office equipment, industrial equipment, and the like that are driven by batteries, such as personal computers and portable communication devices, in addition to vehicles. Further, the non-aqueous secondary battery of the present invention includes wind power generation, solar power generation, hydroelectric power generation and other power system power storage devices and power smoothing devices, power of ships and / or power supply sources of auxiliary machinery, aircraft, Power supply for spacecraft and / or auxiliary equipment, auxiliary power supply for vehicles that do not use electricity as a power source, power supply for mobile home robots, power supply for system backup, power supply for uninterruptible power supply, You may use for the electrical storage apparatus which stores temporarily the electric power required for charge in the charging station for electric vehicles.
　以上、電解液の実施形態を説明したが、本発明は、上記実施形態に限定されるものではない。本発明の要旨を逸脱しない範囲において、当業者が行い得る変更、改良等を施した種々の形態にて実施することができる。 As mentioned above, although embodiment of electrolyte solution was described, this invention is not limited to the said embodiment. The present invention can be implemented in various forms without departing from the gist of the present invention, with modifications and improvements that can be made by those skilled in the art.
　以下に、実施例及び比較例を示し、本発明を具体的に説明する。以下の実施例、比較例及び電池並びにこれらを評価する評価例は、本発明の第１の態様に係る場合は「実施例Ａ－番号」、「比較例Ａ－番号」、「電池Ａ－番号」、「評価例Ａ－番号」で示し、本発明の第２の態様に係る場合は「実施例Ｂ－番号」、「比較例Ｂ－番号」、「電池Ｂ－番号」、「評価例Ｂ－番号」で示し、本発明の第３の態様に係る場合は「実施例Ｃ－番号」、「比較例Ｃ－番号」、「電池Ｃ－番号」、「評価例Ｃ－番号」で示し、本発明の第４の態様に係る場合は「実施例Ｄ－番号」、「比較例Ｄ－番号」、「電池Ｄ－番号」、「評価例Ｄ－番号」で示した。なお、Ａ－、Ｂ－、Ｃ－、Ｄ－を付していない電解液、電池、評価例は、第１～第４の態様に共通するものである。
　なお、本発明は、これらの実施例によって限定されるものではない。以下において、特に断らない限り、「部」とは質量部を意味し、「％」とは質量％を意味する。
（電解液Ｅ１）
　本発明で用いる電解液を以下のとおり製造した。 Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The following examples, comparative examples and batteries, and evaluation examples for evaluating them are “Example A-No.”, “Comparative Example A-No.”, “Battery A-No.” According to the first aspect of the present invention. ”And“ Evaluation Example A-No. ”, And in the case of the second aspect of the present invention,“ Example B-No. ”,“ Comparative Example B-No. ”,“ Battery B-No. ”,“ Evaluation Example B ” In the case of the third aspect of the present invention, it is indicated by “Example C-No.”, “Comparative Example C-No.”, “Battery C-No.”, “Evaluation Example C-No.” The case according to the fourth aspect of the present invention is indicated by “Example D-number”, “Comparative Example D-number”, “Battery D-number”, and “Evaluation Example D-number”. The electrolyte solution, battery, and evaluation example without A-, B-, C-, and D- are common to the first to fourth aspects.
In addition, this invention is not limited by these Examples. In the following, unless otherwise specified, “part” means part by mass, and “%” means mass%.
(Electrolytic solution E1)
The electrolytic solution used in the present invention was produced as follows.
　有機溶媒である１，２－ジメトキシエタン約５ｍＬを、撹拌子及び温度計を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中の１，２－ジメトキシエタンに対し、リチウム塩である（ＣＦ３ＳＯ２）２ＮＬｉを溶液温度が４０℃以下を保つように徐々に加え、溶解させた。約１３ｇの（ＣＦ３ＳＯ２）２ＮＬｉを加えた時点で（ＣＦ３ＳＯ２）２ＮＬｉの溶解が一時停滞したので、上記フラスコを恒温槽に投入し、フラスコ内の溶液温度が５０℃となるよう加温し、（ＣＦ３ＳＯ２）２ＮＬｉを溶解させた。約１５ｇの（ＣＦ３ＳＯ２）２ＮＬｉを加えた時点で（ＣＦ３ＳＯ２）２ＮＬｉの溶解が再び停滞したので、１，２－ジメトキシエタンをピペットで１滴加えたところ、（ＣＦ３ＳＯ２）２ＮＬｉは溶解した。さらに（ＣＦ３ＳＯ２）２ＮＬｉを徐々に加え、所定の（ＣＦ３ＳＯ２）２ＮＬｉを全量加えた。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまで１，２－ジメトキシエタンを加えた。これを電解液Ｅ１とした。得られた電解液は容積２０ｍＬであり、この電解液に含まれる（ＣＦ３ＳＯ２）２ＮＬｉは１８．３８ｇであった。電解液Ｅ１における（ＣＦ３ＳＯ２）２ＮＬｉの濃度は３．２ｍｏｌ／Ｌであった。電解液Ｅ１においては、（ＣＦ３ＳＯ２）２ＮＬｉ１分子に対し１，２－ジメトキシエタン１．６分子が含まれている。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。 About 5 mL of 1,2-dimethoxyethane, which is an organic solvent, was placed in a flask equipped with a stir bar and a thermometer. Under stirring conditions, (CF 3 SO 2 ) 2 NLi, which is a lithium salt, was gradually added to 1,2-dimethoxyethane in the flask so as to keep the solution temperature at 40 ° C. or lower and dissolved. When about 13 g of (CF 3 SO 2 ) 2 NLi was added, the dissolution of (CF 3 SO 2 ) 2 NLi temporarily stagnated. Therefore, the flask was put into a thermostat, and the solution temperature in the flask was 50 ° C. (CF 3 SO 2 ) 2 NLi was dissolved. When about 15 g of (CF 3 SO 2 ) 2 NLi was added, the dissolution of (CF 3 SO 2 ) 2 NLi stagnated again, so 1 drop of 1,2-dimethoxyethane was added with a pipette (CF 3 SO 2 ) 2 NLi dissolved. Further, (CF 3 SO 2 ) 2 NLi was gradually added, and the entire amount of predetermined (CF 3 SO 2 ) 2 NLi was added. The resulting electrolyte was transferred to a 20 mL volumetric flask and 1,2-dimethoxyethane was added until the volume was 20 mL. This was designated as an electrolytic solution E1. The obtained electrolytic solution had a volume of 20 mL, and (CF 3 SO 2 ) 2 NLi contained in this electrolytic solution was 18.38 g. The concentration of (CF 3 SO 2 ) 2 NLi in the electrolytic solution E1 was 3.2 mol / L. In the electrolytic solution E1, 1.6 molecules of 1,2-dimethoxyethane are contained with respect to (CF 3 SO 2 ) 2 NLi1 molecules. The production was performed in a glove box under an inert gas atmosphere.
（電解液Ｅ２）
　１６．０８ｇの（ＣＦ３ＳＯ２）２ＮＬｉを用い、電解液Ｅ１と同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が２．８ｍｏｌ／Ｌである電解液Ｅ２を製造した。電解液Ｅ２においては、（ＣＦ３ＳＯ２）２ＮＬｉ１分子に対し１，２－ジメトキシエタン２．１分子が含まれている。 (Electrolytic solution E2)
Using 16.08 g of (CF 3 SO 2 ) 2 NLi, an electrolytic solution E2 having a concentration of (CF 3 SO 2 ) 2 NLi of 2.8 mol / L was produced in the same manner as the electrolytic solution E1. In the electrolytic solution E2, 2.1 molecules of 1,2-dimethoxyethane are contained per molecule of (CF 3 SO 2 ) 2 NLi.
（電解液Ｅ３）
　有機溶媒であるアセトニトリル約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のアセトニトリルに対し、リチウム塩である（ＣＦ３ＳＯ２）２ＮＬｉを徐々に加え、溶解させた。（ＣＦ３ＳＯ２）２ＮＬｉを全量で１９．５２ｇ加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでアセトニトリルを加えた。これを電解液Ｅ３とした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。 (Electrolytic solution E3)
About 5 mL of acetonitrile, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (CF 3 SO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in acetonitrile in the flask. When 19.52 g of (CF 3 SO 2 ) 2 NLi was added in total, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and acetonitrile was added until the volume was 20 mL. This was designated as an electrolytic solution E3. The production was performed in a glove box under an inert gas atmosphere.
　電解液Ｅ３における（ＣＦ３ＳＯ２）２ＮＬｉの濃度は３．４ｍｏｌ／Ｌであった。電解液Ｅ３においては、（ＣＦ３ＳＯ２）２ＮＬｉ１分子に対しアセトニトリル３分子が含まれている。 The concentration of (CF 3 SO 2 ) 2 NLi in the electrolytic solution E3 was 3.4 mol / L. In the electrolytic solution E3, 3 molecules of acetonitrile are contained with respect to 1 molecule of (CF 3 SO 2 ) 2 NLi.
（電解液Ｅ４）
　２４．１１ｇの（ＣＦ３ＳＯ２）２ＮＬｉを用い、電解液Ｅ３と同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が４．２ｍｏｌ／Ｌである電解液Ｅ４を製造した。電解液Ｅ４においては、（ＣＦ３ＳＯ２）２ＮＬｉ１分子に対しアセトニトリル１．９分子が含まれている。 (Electrolytic solution E4)
Using 24.11 g of (CF 3 SO 2 ) 2 NLi, an electrolytic solution E4 having a concentration of (CF 3 SO 2 ) 2 NLi of 4.2 mol / L was produced in the same manner as the electrolytic solution E3. In the electrolytic solution E4, 1.9 molecules of acetonitrile are contained with respect to (CF 3 SO 2 ) 2 NLi1 molecules.
（電解液Ｅ５）
　リチウム塩として１３．４７ｇの（ＦＳＯ２）２ＮＬｉを用い、有機溶媒として１，２－ジメトキシエタンを用いた以外は、電解液Ｅ３と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が３．６ｍｏｌ／Ｌである電解液Ｅ５を製造した。電解液Ｅ５においては、（ＦＳＯ２）２ＮＬｉ１分子に対し１，２－ジメトキシエタン１．９分子が含まれている。 (Electrolytic solution E5)
Using (FSO 2) 2 NLi of 13.47g lithium salt, except for using 1,2-dimethoxyethane as the organic solvent, in the same manner as the electrolyte solution E3, (FSO 2) concentration of 2 NLi 3 An electrolytic solution E5 having a concentration of 6 mol / L was produced. In the electrolytic solution E5, 1.9 molecules of 1,2-dimethoxyethane are contained per 1 molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ６）
　１４．９７ｇの（ＦＳＯ２）２ＮＬｉを用い、電解液Ｅ５と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が４．０ｍｏｌ／Ｌである電解液Ｅ６を製造した。電解液Ｅ６においては、（ＦＳＯ２）２ＮＬｉ１分子に対し１，２－ジメトキシエタン１．５分子が含まれている。 (Electrolytic solution E6)
Using 14.97 g of (FSO 2 ) 2 NLi, an electrolytic solution E6 having a concentration of (FSO 2 ) 2 NLi of 4.0 mol / L was produced in the same manner as the electrolytic solution E5. In the electrolytic solution E6, 1.5 molecules of 1,2-dimethoxyethane are contained per 1 molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ７）
　リチウム塩として１５．７２ｇの（ＦＳＯ２）２ＮＬｉを用いた以外は、電解液Ｅ３と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が４．２ｍｏｌ／Ｌである電解液Ｅ７を製造した。電解液Ｅ７においては、（ＦＳＯ２）２ＮＬｉ１分子に対しアセトニトリル３分子が含まれている。 (Electrolytic solution E7)
An electrolytic solution E7 having a concentration of 4.2 mol / L of (FSO 2 ) 2 NLi was produced in the same manner as the electrolytic solution E3 except that 15.72 g of (FSO 2 ) 2 NLi was used as the lithium salt. . In the electrolytic solution E7, 3 molecules of acetonitrile are contained with respect to 1 molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ８）
　１６．８３ｇの（ＦＳＯ２）２ＮＬｉを用い、電解液Ｅ７と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が４．５ｍｏｌ／Ｌである電解液Ｅ８を製造した。電解液Ｅ８においては、（ＦＳＯ２）２ＮＬｉ１分子に対しアセトニトリル２．４分子が含まれている。 (Electrolyte E8)
An electrolytic solution E8 having a concentration of (FSO 2 ) 2 NLi of 4.5 mol / L was produced in the same manner as the electrolytic solution E7 using 16.83 g of (FSO 2 ) 2 NLi. In the electrolytic solution E8, 2.4 molecules of acetonitrile are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電解液Ｅ９）
　１８．７１ｇの（ＦＳＯ２）２ＮＬｉを用い、電解液Ｅ７と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が５．０ｍｏｌ／Ｌである電解液Ｅ９を製造した。電解液Ｅ９においては、（ＦＳＯ２）２ＮＬｉ１分子に対しアセトニトリル２．１分子が含まれている。 (Electrolytic solution E9)
An electrolyte solution E9 having a concentration of (FSO 2 ) 2 NLi of 5.0 mol / L was produced using 18.71 g of (FSO 2 ) 2 NLi in the same manner as the electrolyte solution E7. In the electrolytic solution E9, 2.1 molecules of acetonitrile are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電解液Ｅ１０）
　２０．２１ｇの（ＦＳＯ２）２ＮＬｉを用い、電解液Ｅ７と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が５．４ｍｏｌ／Ｌである電解液Ｅ１０を製造した。電解液Ｅ１０においては、（ＦＳＯ２）２ＮＬｉ１分子に対しアセトニトリル２分子が含まれている。 (Electrolytic solution E10)
Using 20.21 g of (FSO 2 ) 2 NLi, an electrolytic solution E10 having a concentration of (FSO 2 ) 2 NLi of 5.4 mol / L was produced in the same manner as the electrolytic solution E7. In the electrolyte solution E10, 2 molecules of acetonitrile are contained with respect to 1 molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ１１）
　有機溶媒であるジメチルカーボネート約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のジメチルカーボネートに対し、リチウム塩である（ＦＳＯ２）２ＮＬｉを徐々に加え、溶解させた。（ＦＳＯ２）２ＮＬｉを全量で１４．６４ｇ加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでジメチルカーボネートを加えた。これを電解液Ｅ１１とした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。 (Electrolytic solution E11)
About 5 mL of dimethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to dimethyl carbonate in the flask and dissolved. When (FSO 2 ) 2 NLi was added in a total amount of 14.64 g, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and dimethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution E11. The production was performed in a glove box under an inert gas atmosphere.
　電解液Ｅ１１における（ＦＳＯ２）２ＮＬｉの濃度は３．９ｍｏｌ／Ｌであった。電解液Ｅ１１においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジメチルカーボネート２分子が含まれている。 The concentration of (FSO 2 ) 2 NLi in the electrolytic solution E11 was 3.9 mol / L. In the electrolytic solution E11, two molecules of dimethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ１２）
　電解液Ｅ１１にジメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が３．４ｍｏｌ／Ｌの電解液Ｅ１２とした。電解液Ｅ１２においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジメチルカーボネート２．５分子が含まれている。 (Electrolytic solution E12)
Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E12 having a (FSO 2 ) 2 NLi concentration of 3.4 mol / L. In the electrolytic solution E12, 2.5 molecules of dimethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電解液Ｅ１３）
　電解液Ｅ１１にジメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が２．９ｍｏｌ／Ｌの電解液Ｅ１３とした。電解液Ｅ１３においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジメチルカーボネート３分子が含まれている。 (Electrolytic solution E13)
Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E13 having a (FSO 2 ) 2 NLi concentration of 2.9 mol / L. In the electrolytic solution E13, three molecules of dimethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ１４）
　電解液Ｅ１１にジメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が２．６ｍｏｌ／Ｌの電解液Ｅ１４とした。電解液Ｅ１４においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジメチルカーボネート３．５分子が含まれている。 (Electrolytic solution E14)
Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E14 having a concentration of (FSO 2 ) 2 NLi of 2.6 mol / L. In the electrolytic solution E14, 3.5 molecules of dimethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電解液Ｅ１５）
　電解液Ｅ１１にジメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が２．０ｍｏｌ／Ｌの電解液Ｅ１５とした。電解液Ｅ１５においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジメチルカーボネート５分子が含まれている。 (Electrolytic solution E15)
Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution E15 having a (FSO 2 ) 2 NLi concentration of 2.0 mol / L. In the electrolytic solution E15, five molecules of dimethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ１６）
　有機溶媒であるエチルメチルカーボネート約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のエチルメチルカーボネートに対し、リチウム塩である（ＦＳＯ２）２ＮＬｉを徐々に加え、溶解させた。（ＦＳＯ２）２ＮＬｉを全量で１２．８１ｇ加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでエチルメチルカーボネートを加えた。これを電解液Ｅ１６とした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。 (Electrolytic solution E16)
About 5 mL of ethyl methyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in ethyl methyl carbonate in the flask. When 12.81 g of (FSO 2 ) 2 NLi was added in total, the mixture was stirred overnight. The obtained electrolytic solution was transferred to a 20 mL volumetric flask, and ethyl methyl carbonate was added until the volume became 20 mL. This was designated as an electrolytic solution E16. The production was performed in a glove box under an inert gas atmosphere.
　電解液Ｅ１６における（ＦＳＯ２）２ＮＬｉの濃度は３．４ｍｏｌ／Ｌであった。電解液Ｅ１６においては、（ＦＳＯ２）２ＮＬｉ１分子に対しエチルメチルカーボネート２分子が含まれている。 The concentration of (FSO 2 ) 2 NLi in the electrolytic solution E16 was 3.4 mol / L. In the electrolytic solution E16, two molecules of ethyl methyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ１７）
　電解液Ｅ１６にエチルメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が２．９ｍｏｌ／Ｌの電解液Ｅ１７とした。電解液Ｅ１７においては、（ＦＳＯ２）２ＮＬｉ１分子に対しエチルメチルカーボネート２．５分子が含まれている。 (Electrolytic solution E17)
The electrolyte solution E16 was diluted by adding ethyl methyl carbonate to obtain an electrolyte solution E17 having a (FSO 2 ) 2 NLi concentration of 2.9 mol / L. In the electrolytic solution E17, 2.5 molecules of ethyl methyl carbonate are contained per 1 molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ１８）
　電解液Ｅ１６にエチルメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が２．２ｍｏｌ／Ｌの電解液Ｅ１８とした。電解液Ｅ１８においては、（ＦＳＯ２）２ＮＬｉ１分子に対しエチルメチルカーボネート３．５分子が含まれている。 (Electrolytic solution E18)
The electrolyte solution E16 was diluted by adding ethyl methyl carbonate to obtain an electrolyte solution E18 having a concentration of (FSO 2 ) 2 NLi of 2.2 mol / L. In the electrolytic solution E18, 3.5 molecules of ethyl methyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電解液Ｅ１９）
　有機溶媒であるジエチルカーボネート約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のジエチルカーボネートに対し、リチウム塩である（ＦＳＯ２）２ＮＬｉを徐々に加え、溶解させた。（ＦＳＯ２）２ＮＬｉを全量で１１．３７ｇ加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでジエチルカーボネートを加えた。これを電解液Ｅ１９とした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。 (Electrolytic solution E19)
About 5 mL of diethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stirring bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in diethyl carbonate in the flask. When 11.37 g of the total amount of (FSO 2 ) 2 NLi was added, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and diethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution E19. The production was performed in a glove box under an inert gas atmosphere.
　電解液Ｅ１９における（ＦＳＯ２）２ＮＬｉの濃度は３．０ｍｏｌ／Ｌであった。電解液Ｅ１９においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジエチルカーボネート２分子が含まれている。 The concentration of (FSO 2 ) 2 NLi in the electrolytic solution E19 was 3.0 mol / L. In the electrolytic solution E19, two molecules of diethyl carbonate are contained with respect to one molecule of (FSO 2 ) 2 NLi.
（電解液Ｅ２０）
　電解液Ｅ１９にジエチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が２．６ｍｏｌ／Ｌの電解液Ｅ２０とした。電解液Ｅ２０においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジエチルカーボネート２．５分子が含まれている。 (Electrolytic solution E20)
Diethyl carbonate was added to the electrolytic solution E19 for dilution to obtain an electrolytic solution E20 having a (FSO 2 ) 2 NLi concentration of 2.6 mol / L. In the electrolytic solution E20, 2.5 molecules of diethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電解液Ｅ２１）
　電解液Ｅ１９にジエチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が２．０ｍｏｌ／Ｌの電解液Ｅ２１とした。電解液Ｅ２１においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジエチルカーボネート３．５分子が含まれている。 (Electrolytic solution E21)
Diethyl carbonate was added to the electrolytic solution E19 for dilution to obtain an electrolytic solution E21 having a (FSO 2 ) 2 NLi concentration of 2.0 mol / L. In the electrolytic solution E21, 3.5 molecules of diethyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電解液Ｃ１）
　５．７４ｇの（ＣＦ３ＳＯ２）２ＮＬｉを用い、有機溶媒として１，２－ジメトキシエタンを用いた以外は、電解液Ｅ３と同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が１．０ｍｏｌ／Ｌである電解液Ｃ１を製造した。電解液Ｃ１においては、（ＣＦ３ＳＯ２）２ＮＬｉ１分子に対し１，２－ジメトキシエタン８．３分子が含まれている。 (Electrolytic solution C1)
Using (CF 3 SO 2) 2 NLi of 5.74 g, as except for using 1,2-dimethoxyethane organic solvents, in the same manner as the electrolyte solution E3, is (CF 3 SO 2) concentration of 2 NLi Electrolyte C1 which is 1.0 mol / L was manufactured. In the electrolytic solution C1, 8.3 molecules of 1,2-dimethoxyethane are contained with respect to (CF 3 SO 2 ) 2 NLi1 molecules.
（電解液Ｃ２）
　５．７４ｇの（ＣＦ３ＳＯ２）２ＮＬｉを用い、電解液Ｅ３と同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が１．０ｍｏｌ／Ｌである電解液Ｃ２を製造した。電解液Ｃ２においては、（ＣＦ３ＳＯ２）２ＮＬｉ１分子に対しアセトニトリル１６分子が含まれている。 (Electrolytic solution C2)
Using 5.74 g of (CF 3 SO 2 ) 2 NLi, an electrolytic solution C2 having a concentration of (CF 3 SO 2 ) 2 NLi of 1.0 mol / L was produced in the same manner as the electrolytic solution E3. In the electrolytic solution C2, 16 molecules of acetonitrile are contained with respect to (CF 3 SO 2 ) 2 NLi1 molecule.
（電解液Ｃ３）
　３．７４ｇの（ＦＳＯ２）２ＮＬｉを用い、電解液Ｅ５と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が１．０ｍｏｌ／Ｌである電解液Ｃ３を製造した。電解液Ｃ３においては、（ＦＳＯ２）２ＮＬｉ１分子に対し１，２－ジメトキシエタン８．８分子が含まれている。 (Electrolytic solution C3)
Using 3.74 g of (FSO 2 ) 2 NLi, an electrolytic solution C3 having a concentration of (FSO 2 ) 2 NLi of 1.0 mol / L was produced in the same manner as the electrolytic solution E5. In the electrolytic solution C3, 8.8 molecules of 1,2-dimethoxyethane are contained per molecule of (FSO 2 ) 2 NLi.
（電解液Ｃ４）
　３．７４ｇの（ＦＳＯ２）２ＮＬｉを用い、電解液Ｅ７と同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が１．０ｍｏｌ／Ｌである電解液Ｃ４を製造した。電解液Ｃ４においては、（ＦＳＯ２）２ＮＬｉ１分子に対しアセトニトリル１７分子が含まれている。 (Electrolytic solution C4)
Using 3.74 g of (FSO 2 ) 2 NLi, an electrolytic solution C4 having a concentration of (FSO 2 ) 2 NLi of 1.0 mol / L was produced in the same manner as the electrolytic solution E7. In the electrolyte solution C4, 17 molecules of acetonitrile are contained with respect to (FSO 2 ) 2 NLi1 molecule.
（電解液Ｃ５）
　有機溶媒としてエチレンカーボネート及びジエチルカーボネートの混合溶媒（体積比３：７、以下、「ＥＣ／ＤＥＣ」ということがある。）を用い、リチウム塩として３．０４ｇのＬｉＰＦ６を用いた以外は、電解液Ｅ３と同様の方法で、ＬｉＰＦ６の濃度が１．０ｍｏｌ／Ｌである電解液Ｃ５を製造した。 (Electrolytic solution C5)
Except that a mixed solvent of ethylene carbonate and diethyl carbonate (volume ratio 3: 7, hereinafter referred to as “EC / DEC”) is used as the organic solvent, and 3.04 g of LiPF 6 is used as the lithium salt. An electrolytic solution C5 having a LiPF 6 concentration of 1.0 mol / L was produced in the same manner as in the liquid E3.
（電解液Ｃ６）
　電解液Ｅ１１にジメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が１．１ｍｏｌ／Ｌの電解液Ｃ６とした。電解液Ｃ６においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジメチルカーボネート１０分子が含まれている。 (Electrolytic solution C6)
Dimethyl carbonate was added to the electrolytic solution E11 for dilution to obtain an electrolytic solution C6 having a (FSO 2 ) 2 NLi concentration of 1.1 mol / L. In the electrolytic solution C6, 10 molecules of dimethyl carbonate are contained per 1 molecule of (FSO 2 ) 2 NLi.
（電解液Ｃ７）
　電解液Ｅ１６にエチルメチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が１．１ｍｏｌ／Ｌの電解液Ｃ７とした。電解液Ｃ７においては、（ＦＳＯ２）２ＮＬｉ１分子に対しエチルメチルカーボネート８分子が含まれている。 (Electrolytic solution C7)
The electrolyte solution E16 was diluted by adding ethyl methyl carbonate to obtain an electrolyte solution C7 having a (FSO 2 ) 2 NLi concentration of 1.1 mol / L. In the electrolytic solution C7, 8 molecules of ethyl methyl carbonate are contained with respect to (FSO 2 ) 2 NLi1 molecule.
（電解液Ｃ８）
　電解液Ｅ１９にジエチルカーボネートを加えて希釈し、（ＦＳＯ２）２ＮＬｉの濃度が１．１ｍｏｌ／Ｌの電解液Ｃ８とした。電解液Ｃ８においては、（ＦＳＯ２）２ＮＬｉ１分子に対しジエチルカーボネート７分子が含まれている。 (Electrolytic solution C8)
Diethyl carbonate was added to the electrolytic solution E19 for dilution to obtain an electrolytic solution C8 having a (FSO 2 ) 2 NLi concentration of 1.1 mol / L. In the electrolytic solution C8, 7 molecules of diethyl carbonate are contained per 1 molecule of (FSO 2 ) 2 NLi.
　表４に電解液Ｅ１～Ｅ２１及び電解液Ｃ１～Ｃ８の一覧を示す。 Table 4 shows a list of the electrolytic solutions E1 to E21 and the electrolytic solutions C1 to C8.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
（評価例１：ＩＲ測定）
　電解液Ｅ３、電解液Ｅ４、電解液Ｅ７、電解液Ｅ８、電解液Ｅ１０、電解液Ｃ２、電解液Ｃ４、並びに、アセトニトリル、（ＣＦ３ＳＯ２）２ＮＬｉ、（ＦＳＯ２）２ＮＬｉにつき、以下の条件でＩＲ測定を行った。２１００ｃｍ－１～２４００ｃｍ－１の範囲のＩＲスペクトルをそれぞれ図１～図１０に示す。さらに、電解液Ｅ１１～Ｅ１５、Ｃ６、ジメチルカーボネート、Ｅ１６－Ｅ１８、Ｃ７、エチルメチルカーボネート、Ｅ１９－Ｅ２１、Ｃ８、ジエチルカーボネートにつき、以下の条件でＩＲ測定を行った。１９００～１６００ｃｍ－１の範囲のＩＲスペクトルをそれぞれ図１１～図２７に示す。また、（ＦＳＯ２）２ＮＬｉにつき、１９００～１６００ｃｍ－１の範囲のＩＲスペクトルを図２８に示す。図の横軸は波数（ｃｍ－１）であり、縦軸は吸光度（反射吸光度）である。 (Evaluation Example 1: IR measurement)
Electrolytic solution E3, electrolytic solution E4, electrolytic solution E7, electrolytic solution E8, electrolytic solution E10, electrolytic solution C2, electrolytic solution C4, and acetonitrile, (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi are as follows: The IR measurement was performed under the following conditions. IR spectra in the range of 2100 cm −1 to 2400 cm −1 are shown in FIGS. 1 to 10, respectively. Further, IR measurement was performed on the electrolytic solutions E11 to E15, C6, dimethyl carbonate, E16-E18, C7, ethyl methyl carbonate, E19-E21, C8, and diethyl carbonate under the following conditions. IR spectra in the range of 1900 to 1600 cm −1 are shown in FIGS. 11 to 27, respectively. In addition, FIG. 28 shows an IR spectrum in the range of 1900 to 1600 cm −1 for (FSO 2 ) 2 NLi. The horizontal axis in the figure is the wave number (cm −1 ), and the vertical axis is the absorbance (reflection absorbance).
　ＩＲ測定条件
　装置：ＦＴ－ＩＲ（ブルカーオプティクス社製）
　測定条件：ＡＴＲ法（ダイヤモンド使用）
　測定雰囲気：不活性ガス雰囲気下 IR measurement conditions Device: FT-IR (Bruker Optics)
Measurement conditions: ATR method (using diamond)
Measurement atmosphere: Inert gas atmosphere
　図８で示されるアセトニトリルのＩＲスペクトルの２２５０ｃｍ－１付近には、アセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークが観察された。なお、図９で示される（ＣＦ３ＳＯ２）２ＮＬｉのＩＲスペクトル及び図１０で示される（ＦＳＯ２）２ＮＬｉのＩＲスペクトルの２２５０ｃｍ－１付近には、特段のピークが観察されなかった。 In the vicinity of 2250 cm −1 of the IR spectrum of acetonitrile shown in FIG. 8, a characteristic peak derived from the stretching vibration of the triple bond between C and N of acetonitrile was observed. Note that no special peak was observed in the vicinity of 2250 cm −1 of the IR spectrum of (CF 3 SO 2 ) 2 NLi shown in FIG. 9 and the IR spectrum of (FSO 2 ) 2 NLi shown in FIG.
　図１で示される電解液Ｅ３のＩＲスペクトルには、２２５０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．００６９９）観察された。さらに図１のＩＲスペクトルには、２２５０ｃｍ－１付近から高波数側にシフトした２２８０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．０５８２８で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝８×Ｉｏであった。 In the IR spectrum of the electrolytic solution E3 shown in FIG. 1, a characteristic peak derived from the stretching vibration of the triple bond between C and N of acetonitrile is slightly observed (Io = 0.00699) in the vicinity of 2250 cm −1. It was. More IR spectrum of FIG. 1, 2250 cm characteristic peaks peak intensity derived from the stretching vibration of the triple bond between the vicinity of -1 acetonitrile near 2280 cm -1 shifted to the high frequency side C and N Is = 0 .05828. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 8 × Io.
　図２で示される電解液Ｅ４のＩＲスペクトルには、２２５０ｃｍ－１付近にアセトニトリル由来のピークが観察されず、２２５０ｃｍ－１付近から高波数側にシフトした２２８０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．０５２３４で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであった。 The IR spectrum of the electrolyte E4 shown in FIG. 2, 2250 cm -1 peak derived from acetonitrile was not observed in the vicinity, between 2250 cm from the vicinity -1 acetonitrile near 2280 cm -1 shifted to the high frequency side C and N A characteristic peak derived from the stretching vibration of the triple bond was observed at a peak intensity Is = 0.05234. The relationship between the peak intensities of Is and Io was Is> Io.
　図３で示される電解液Ｅ７のＩＲスペクトルには、２２５０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．００９９７）観察された。さらに図３のＩＲスペクトルには、２２５０ｃｍ－１付近から高波数側にシフトした２２８０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．０８２８８で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝８×Ｉｏであった。図４で示される電解液Ｅ８のＩＲスペクトルについても、図３のＩＲチャートと同様の強度のピークが同様の波数に観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝１１×Ｉｏであった。 In the IR spectrum of the electrolytic solution E7 shown in FIG. 3, a characteristic peak derived from the stretching vibration of the triple bond between C and N of acetonitrile is slightly observed (Io = 0.00997) in the vicinity of 2250 cm −1. It was. More IR spectrum of FIG. 3, 2250 cm characteristic peaks peak intensity derived from the stretching vibration of the triple bond between the vicinity of -1 acetonitrile near 2280 cm -1 shifted to the high frequency side C and N Is = 0 .08288. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 8 × Io. Also in the IR spectrum of the electrolytic solution E8 shown in FIG. 4, the same intensity peak as that in the IR chart of FIG. 3 was observed at the same wave number. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 11 × Io.
　図５で示される電解液Ｅ１０のＩＲスペクトルには、２２５０ｃｍ－１付近にアセトニトリル由来のピークが観察されず、２２５０ｃｍ－１付近から高波数側にシフトした２２８０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．０７３５０で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであった。 FIG The IR spectrum of the electrolyte E10 represented by 5, is not a peak derived from acetonitrile observed around 2250 cm -1, inter 2250 cm from the vicinity -1 shifted acetonitrile 2280cm around -1 to the high frequency side C and N A characteristic peak derived from the stretching vibration of the triple bond was observed at a peak intensity Is = 0.07350. The relationship between the peak intensities of Is and Io was Is> Io.
　図６で示される電解液Ｃ２のＩＲスペクトルには、図８と同じく、２２５０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｏ＝０．０４４４１で観察された。さらに図６のＩＲスペクトルには、２２５０ｃｍ－１付近から高波数側にシフトした２２８０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．０３０１８で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＜Ｉｏであった。 In the IR spectrum of the electrolytic solution C2 shown in FIG. 6, a characteristic peak derived from the stretching vibration of the triple bond between C and N of acetonitrile is observed in the vicinity of 2250 cm −1 in the IR spectrum of FIG. Observed at 04441. More IR spectrum of FIG. 6, 2250 cm characteristic peaks peak intensity derived from the stretching vibration of the triple bond between the vicinity of -1 acetonitrile near 2280 cm -1 shifted to the high frequency side C and N Is = 0 .03018. The relationship between the peak intensities of Is and Io was Is <Io.
　図７で示される電解液Ｃ４のＩＲスペクトルには、図８と同じく、２２５０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｏ＝０．０４９７５で観察された。さらに図７のＩＲスペクトルには、２２５０ｃｍ－１付近から高波数側にシフトした２２８０ｃｍ－１付近にアセトニトリルのＣ及びＮ間の三重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．０３８０４で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＜Ｉｏであった。 In the IR spectrum of the electrolytic solution C4 shown in FIG. 7, a characteristic peak derived from the stretching vibration of the triple bond between C and N of acetonitrile is observed in the vicinity of 2250 cm −1 in the IR spectrum of FIG. Observed at 04975. More IR spectrum of Figure 7, 2250 cm characteristic peaks peak intensity derived from the stretching vibration of the triple bond between the vicinity of -1 acetonitrile near 2280 cm -1 shifted to the high frequency side C and N Is = 0 .03804. The relationship between the peak intensities of Is and Io was Is <Io.
　図１７で示されるジメチルカーボネートのＩＲスペクトルの１７５０ｃｍ－１付近には、ジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークが観察された。なお、図２８で示される（ＦＳＯ２）２ＮＬｉのＩＲスペクトルの１７５０ｃｍ－１付近には、特段のピークが観察されなかった。 In the vicinity of 1750 cm −1 of the IR spectrum of dimethyl carbonate shown in FIG. 17, a characteristic peak derived from the stretching vibration of the double bond between C and O of dimethyl carbonate was observed. Note that no special peak was observed in the vicinity of 1750 cm −1 in the IR spectrum of (FSO 2 ) 2 NLi shown in FIG.
　図１１で示される電解液Ｅ１１のＩＲスペクトルには、１７５０ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．１６６２８）観察された。さらに図１１のＩＲスペクトルには、１７５０ｃｍ－１付近から低波数側にシフトした１７１７ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．４８０３２で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝２．８９×Ｉｏであった。 In the IR spectrum of the electrolytic solution E11 shown in FIG. 11, a characteristic peak derived from the stretching vibration of the double bond between C and O of dimethyl carbonate is slightly observed at around 1750 cm −1 (Io = 0.166628). Observed. More IR spectrum of Figure 11, characteristic peaks peak intensity Is derived from stretching vibration of double bonds between C and O of dimethyl carbonate in the vicinity of 1717 cm -1 shifted from the vicinity of 1750 cm -1 to a lower wavenumber side = 0.48032. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 2.89 × Io.
　図１２で示される電解液Ｅ１２のＩＲスペクトルには、１７５０ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．１８１２９）観察された。さらに図１２のＩＲスペクトルには、１７５０ｃｍ－１付近から低波数側にシフトした１７１７ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．５２００５で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝２．８７×Ｉｏであった。 In the IR spectrum of the electrolytic solution E12 shown in FIG. 12, a characteristic peak derived from stretching vibration of a double bond between C and O of dimethyl carbonate is slightly present (Io = 0.18129) in the vicinity of 1750 cm −1. Observed. More IR spectrum of Figure 12, characteristic peaks peak intensity Is derived from stretching vibration of double bonds between C and O of dimethyl carbonate in the vicinity of 1717 cm -1 shifted from the vicinity of 1750 cm -1 to a lower wavenumber side = 0.52005 was observed. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 2.87 × Io.
　図１３で示される電解液Ｅ１３のＩＲスペクトルには、１７５０ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．２０２９３）観察された。さらに図１３のＩＲスペクトルには、１７５０ｃｍ－１付近から低波数側にシフトした１７１７ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．５３０９１で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝２．６２×Ｉｏであった。 In the IR spectrum of the electrolytic solution E13 shown in FIG. 13, a characteristic peak derived from the stretching vibration of the double bond between C and O of dimethyl carbonate is slightly present in the vicinity of 1750 cm −1 (Io = 0.20293). Observed. More IR spectrum of Figure 13, characteristic peaks peak intensity Is derived from stretching vibration of double bonds between C and O of dimethyl carbonate in the vicinity of 1717 cm -1 shifted from the vicinity of 1750 cm -1 to a lower wavenumber side = 0.53091. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 2.62 × Io.
　図１４で示される電解液Ｅ１４のＩＲスペクトルには、１７５０ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．２３８９１）観察された。さらに図１４のＩＲスペクトルには、１７５０ｃｍ－１付近から低波数側にシフトした１７１７ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．５３０９８で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝２．２２×Ｉｏであった。 In the IR spectrum of the electrolytic solution E14 shown in FIG. 14, there is a slight characteristic peak (Io = 0.38991) derived from the stretching vibration of the double bond between C and O of dimethyl carbonate in the vicinity of 1750 cm −1. Observed. More IR spectrum of Figure 14, characteristic peaks peak intensity Is derived from stretching vibration of double bonds between C and O of dimethyl carbonate in the vicinity of 1717 cm -1 shifted from the vicinity of 1750 cm -1 to a lower wavenumber side = 0.53098. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 2.22 × Io.
　図１５で示される電解液Ｅ１５のＩＲスペクトルには、１７５０ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．３０５１４）観察された。さらに図１５のＩＲスペクトルには、１７５０ｃｍ－１付近から低波数側にシフトした１７１７ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．５０２２３で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝１．６５×Ｉｏであった。 In the IR spectrum of the electrolytic solution E15 shown in FIG. 15, a characteristic peak derived from the stretching vibration of the double bond between C and O of dimethyl carbonate is slightly present at around 1750 cm −1 (Io = 0.050514). Observed. More IR spectrum of Figure 15, characteristic peaks peak intensity Is derived from stretching vibration of double bonds between C and O of dimethyl carbonate in the vicinity of 1717 cm -1 shifted from the vicinity of 1750 cm -1 to a lower wavenumber side = 0.50223. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 1.65 × Io.
　図１６で示される電解液Ｃ６のＩＲスペクトルには、１７５０ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークが（Ｉｏ＝０．４８２０４）観察された。さらに図１６のＩＲスペクトルには、１７５０ｃｍ－１付近から低波数側にシフトした１７１７ｃｍ－１付近にジメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．３９２４４で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＜Ｉｏであった。 In the IR spectrum of the electrolytic solution C6 shown in FIG. 16, a characteristic peak (Io = 0.48204) derived from stretching vibration of a double bond between C and O of dimethyl carbonate is observed near 1750 cm −1. It was. More IR spectrum of Figure 16, characteristic peaks peak intensity Is derived from stretching vibration of double bonds between C and O of dimethyl carbonate in the vicinity of 1717 cm -1 shifted from the vicinity of 1750 cm -1 to a lower wavenumber side = 0.39244. The relationship between the peak intensities of Is and Io was Is <Io.
　図２２で示されるエチルメチルカーボネートのＩＲスペクトルの１７４５ｃｍ－１付近には、エチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークが観察された。 In the vicinity of 1745 cm −1 of the IR spectrum of ethyl methyl carbonate shown in FIG. 22, a characteristic peak derived from the stretching vibration of the double bond between C and O of ethyl methyl carbonate was observed.
　図１８で示される電解液Ｅ１６のＩＲスペクトルには、１７４５ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．１３５８２）観察された。さらに図１８のＩＲスペクトルには、１７４５ｃｍ－１付近から低波数側にシフトした１７１１ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．４５８８８で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝３．３８×Ｉｏであった。 In the IR spectrum of the electrolytic solution E16 shown in FIG. 18, a characteristic peak derived from the stretching vibration of the double bond between C and O of ethylmethyl carbonate is slightly observed at around 1745 cm −1 (Io = 0.13582). ) Observed. Further, in the IR spectrum of FIG. 18, a characteristic peak derived from the stretching vibration of the double bond between C and O of ethylmethyl carbonate is observed at about 1711 cm −1 shifted from the vicinity of 1745 cm −1 to the lower wavenumber side. Observed at Is = 0.45888. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 3.38 × Io.
　図１９で示される電解液Ｅ１７のＩＲスペクトルには、１７４５ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．１５１５１）観察された。さらに図１９のＩＲスペクトルには、１７４５ｃｍ－１付近から低波数側にシフトした１７１１ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．４８７７９で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝３．２２×Ｉｏであった。 In the IR spectrum of the electrolytic solution E17 shown in FIG. 19, there is a slight characteristic peak (Io = 0.151151) derived from the stretching vibration of the double bond between C and O of ethylmethyl carbonate in the vicinity of 1745 cm −1. ) Observed. Further, in the IR spectrum of FIG. 19, a characteristic peak derived from the stretching vibration of the double bond between C and O of ethylmethyl carbonate is observed near 1711 cm −1 shifted from the vicinity of 1745 cm −1 to the lower wavenumber side. Observed at Is = 0.48779. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 3.22 × Io.
　図２０で示される電解液Ｅ１８のＩＲスペクトルには、１７４５ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．２０１９１）観察された。さらに図２０のＩＲスペクトルには、１７４５ｃｍ－１付近から低波数側にシフトした１７１１ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．４８４０７で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝２．４０×Ｉｏであった。 In the IR spectrum of the electrolytic solution E18 shown in FIG. 20, a characteristic peak derived from the stretching vibration of the double bond between C and O of ethylmethyl carbonate is slightly present in the vicinity of 1745 cm −1 (Io = 0.2091). ) Observed. Further, in the IR spectrum of FIG. 20, a characteristic peak derived from the stretching vibration of the double bond between C and O of ethylmethyl carbonate is observed near 1711 cm −1 shifted from the vicinity of 1745 cm −1 to the lower wavenumber side. Observed at Is = 0.408407. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 2.40 × Io.
　図２１で示される電解液Ｃ７のＩＲスペクトルには、１７４５ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークが（Ｉｏ＝０．４１９０７）観察された。さらに図２１のＩＲスペクトルには、１７４５ｃｍ－１付近から低波数側にシフトした１７１１ｃｍ－１付近にエチルメチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．３３９２９で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＜Ｉｏであった。 In the IR spectrum of the electrolytic solution C7 shown in FIG. 21, a characteristic peak (Io = 0.41907) derived from stretching vibration of a double bond between C and O of ethylmethyl carbonate is observed near 1745 cm −1. It was done. Furthermore, in the IR spectrum of FIG. 21, a characteristic peak derived from the stretching vibration of the double bond between C and O of ethylmethyl carbonate is observed near 1711 cm −1 shifted from the vicinity of 1745 cm −1 to the lower wavenumber side. Observed at Is = 0.33929. The relationship between the peak intensities of Is and Io was Is <Io.
　図２７で示されるジエチルカーボネートのＩＲスペクトルの１７４２ｃｍ－１付近には、ジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークが観察された。 In the vicinity of 1742 cm −1 of the IR spectrum of diethyl carbonate shown in FIG. 27, a characteristic peak derived from the stretching vibration of the double bond between C and O of diethyl carbonate was observed.
　図２３で示される電解液Ｅ１９のＩＲスペクトルには、１７４２ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．１１２０２）観察された。さらに図２３のＩＲスペクトルには、１７４２ｃｍ－１付近から低波数側にシフトした１７０６ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．４２９２５で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝３．８３×Ｉｏであった。 In the IR spectrum of the electrolytic solution E19 shown in FIG. 23, a characteristic peak derived from stretching vibration of a double bond between C and O of diethyl carbonate is slightly present in the vicinity of 1742 cm −1 (Io = 0.12002). Observed. Further, in the IR spectrum of FIG. 23, a characteristic peak derived from the stretching vibration of the double bond between C and O of diethyl carbonate is observed near the peak intensity Is near 1706 cm −1 shifted from the vicinity of 1742 cm −1 to the low wavenumber side. = 0.42925. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 3.83 × Io.
　図２４で示される電解液Ｅ２０のＩＲスペクトルには、１７４２ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．１５２３１）観察された。さらに図２４のＩＲスペクトルには、１７４２ｃｍ－１付近から低波数側にシフトした１７０６ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．４５６７９で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝３．００×Ｉｏであった。 In the IR spectrum of the electrolytic solution E20 shown in FIG. 24, a characteristic peak derived from the stretching vibration of the double bond between C and O of diethyl carbonate is slightly present in the vicinity of 1742 cm −1 (Io = 0.15231). Observed. Furthermore, in the IR spectrum of FIG. 24, a characteristic peak derived from the stretching vibration of the double bond between C and O of diethyl carbonate is observed near 1706 cm −1 shifted from the vicinity of 1742 cm −1 to the low wavenumber side. = 0.45679. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 3.00 × Io.
　図２５で示される電解液Ｅ２１のＩＲスペクトルには、１７４２ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがわずかに（Ｉｏ＝０．２０３３７）観察された。さらに図２５のＩＲスペクトルには、１７４２ｃｍ－１付近から低波数側にシフトした１７０６ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．４３８４１で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＞Ｉｏであり、Ｉｓ＝２．１６×Ｉｏであった。 In the IR spectrum of the electrolytic solution E21 shown in FIG. 25, a characteristic peak derived from the stretching vibration of the double bond between C and O of diethyl carbonate is slightly present in the vicinity of 1742 cm −1 (Io = 0.20337). Observed. Furthermore, in the IR spectrum of FIG. 25, a characteristic peak derived from the stretching vibration of the double bond between C and O of diethyl carbonate is observed near the peak intensity Is near 1706 cm −1 shifted from the vicinity of 1742 cm −1 to the low wavenumber side. = 0.43841. The relationship between the peak intensities of Is and Io was Is> Io, and Is = 2.16 × Io.
　図２６で示される電解液Ｃ８のＩＲスペクトルには、１７４２ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークが（Ｉｏ＝０．３９６３６）観察された。さらに図２６のＩＲスペクトルには、１７４２ｃｍ－１付近から低波数側にシフトした１７０９ｃｍ－１付近にジエチルカーボネートのＣ及びＯ間の二重結合の伸縮振動に由来する特徴的なピークがピーク強度Ｉｓ＝０．３１１２９で観察された。ＩｓとＩｏのピーク強度の関係はＩｓ＜Ｉｏであった。 In the IR spectrum of the electrolytic solution C8 shown in FIG. 26, a characteristic peak (Io = 0.396636) derived from the stretching vibration of the double bond between C and O of diethyl carbonate is observed in the vicinity of 1742 cm −1. It was. More IR spectrum of Figure 26, characteristic peaks peak intensity Is derived from stretching vibration of double bonds between C and O in diethyl carbonate in the vicinity of 1709 cm -1 shifted from the vicinity of 1742 cm -1 to a lower wavenumber side = 0.31129. The relationship between the peak intensities of Is and Io was Is <Io.
（評価例２：イオン伝導度）
　電解液Ｅ１、Ｅ２、電解液Ｅ４～Ｅ６、電解液Ｅ８、電解液Ｅ９、電解液Ｅ１１、電解液Ｅ１３、電解液Ｅ１６、電解液Ｅ１９のイオン伝導度を以下の条件で測定した。結果を表５に示す。 (Evaluation Example 2: Ionic conductivity)
The ionic conductivities of the electrolytic solutions E1, E2, electrolytic solutions E4 to E6, electrolytic solution E8, electrolytic solution E9, electrolytic solution E11, electrolytic solution E13, electrolytic solution E16, and electrolytic solution E19 were measured under the following conditions. The results are shown in Table 5.
　イオン伝導度測定条件
　Ａｒ雰囲気下、白金極を備えたセル定数既知のガラス製セルに、電解液を封入し、３０℃、１ｋＨｚでのインピーダンスを測定した。インピーダンスの測定結果から、イオン伝導度を算出した。測定機器はＳｏｌａｒｔｒｏｎ　１４７０５５ＢＥＣ（ソーラトロン社）を使用した。 Ionic conductivity measurement conditions In an Ar atmosphere, an electrolytic solution was sealed in a glass cell with a platinum constant and a known cell constant, and impedance at 30 ° C. and 1 kHz was measured. The ion conductivity was calculated from the impedance measurement result. As the measuring instrument, Solartron 147055BEC (Solartron) was used.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　電解液Ｅ１、電解液Ｅ２、電解液Ｅ４～Ｅ６、電解液Ｅ８、電解液Ｅ９、電解液Ｅ１１、電解液Ｅ１３、電解液Ｅ１６、電解液Ｅ１９は、いずれもイオン伝導性を示した。よって、本発明の電解液は、いずれも各種の電池の電解液として機能し得ると理解できる。 Electrolytic solution E1, electrolytic solution E2, electrolytic solutions E4 to E6, electrolytic solution E8, electrolytic solution E9, electrolytic solution E11, electrolytic solution E13, electrolytic solution E16, and electrolytic solution E19 all exhibited ion conductivity. Therefore, it can be understood that the electrolytic solution of the present invention can function as an electrolytic solution for various batteries.
（評価例３：粘度）
　電解液Ｅ１、電解液Ｅ２、電解液Ｅ４～Ｅ６、電解液Ｅ８、電解液Ｅ９、電解液Ｅ１１、電解液Ｅ１３、電解液Ｅ１６、電解液Ｅ１９並びに電解液Ｃ１～Ｃ４、電解液Ｃ６～Ｃ８の粘度を以下の条件で測定した。結果を表６に示す。 (Evaluation Example 3: Viscosity)
Electrolytic solution E1, electrolytic solution E2, electrolytic solutions E4 to E6, electrolytic solution E8, electrolytic solution E9, electrolytic solution E11, electrolytic solution E13, electrolytic solution E16, electrolytic solution E19 and electrolytic solutions C1 to C4 and electrolytic solutions C6 to C8 The viscosity was measured under the following conditions. The results are shown in Table 6.
　粘度測定条件
　落球式粘度計（ＡｎｔｏｎＰａａｒ　ＧｍｂＨ（アントンパール社）製　Ｌｏｖｉｓ　２０００ Ｍ）を用い、Ａｒ雰囲気下、試験セルに電解液を封入し、３０℃の条件下で粘度を測定した。 Viscosity measurement conditions Using a falling ball viscometer (Lovis 2000 M manufactured by Anton Paar GmbH (Anton Paar)), an electrolytic solution was sealed in a test cell under an Ar atmosphere, and the viscosity was measured at 30 ° C.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　電解液Ｅ１、電解液Ｅ２、電解液Ｅ４～Ｅ６、電解液Ｅ８、電解液Ｅ９、電解液Ｅ１１、電解液Ｅ１３、電解液Ｅ１６、電解液Ｅ１９の粘度は、電解液Ｃ１～Ｃ４、電解液Ｃ６～Ｃ８の粘度と比較して、著しく高かった。よって、本発明の電解液を用いた電池であれば、仮に電池が破損したとしても、電解液漏れが抑制される。 Electrolytic Solution E1, Electrolytic Solution E2, Electrolytic Solutions E4 to E6, Electrolytic Solution E8, Electrolytic Solution E9, Electrolytic Solution E11, Electrolytic Solution E13, Electrolytic Solution E16, and Electrolytic Solution E19 have Viscosities of Electrolytic Solutions C1 to C4 and Electrolytic Solution C6 It was significantly higher than the viscosity of ~ C8. Therefore, if the battery uses the electrolytic solution of the present invention, leakage of the electrolytic solution is suppressed even if the battery is damaged.
（評価例４：揮発性）
　電解液Ｅ２、Ｅ４、Ｅ８、Ｅ１１、Ｅ１３、電解液Ｃ１、Ｃ２、Ｃ４、Ｃ６の揮発性を以下の方法で測定した。 (Evaluation Example 4: Volatility)
The volatility of the electrolytic solutions E2, E4, E8, E11, E13 and the electrolytic solutions C1, C2, C4, C6 was measured by the following method.
　約１０ｍｇの電解液をアルミニウム製のパンに入れ、熱重量測定装置（ＴＡインスツルメント社製、ＳＤＴ６００）に配置し、室温での電解液の重量変化を測定した。重量変化（質量％）を時間で微分することで揮発速度を算出した。揮発速度のうち最大のものを選択し、表７に示した。 About 10 mg of the electrolytic solution was put in an aluminum pan and placed in a thermogravimetric apparatus (TA Instruments, SDT600), and the weight change of the electrolytic solution at room temperature was measured. The volatilization rate was calculated by differentiating the weight change (mass%) with time. The maximum volatilization rate was selected and shown in Table 7.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　電解液Ｅ２、Ｅ４、Ｅ８、Ｅ１１、Ｅ１３の最大揮発速度は、電解液Ｃ１、Ｃ２、Ｃ４、Ｃ６の最大揮発速度と比較して、著しく小さかった。よって、本発明の電解液を用いた電池は、仮に損傷したとしても、電解液の揮発速度が小さいため、電池外への有機溶媒の急速な揮発が抑制される。 The maximum volatilization rates of the electrolytic solutions E2, E4, E8, E11, and E13 were significantly smaller than the maximum volatilization rates of the electrolytic solutions C1, C2, C4, and C6. Therefore, even if the battery using the electrolytic solution of the present invention is damaged, the volatilization rate of the electrolytic solution is small, so that rapid volatilization of the organic solvent to the outside of the battery is suppressed.
（評価例５：燃焼性）
　電解液Ｅ４、電解液Ｃ２の燃焼性を以下の方法で試験した。 (Evaluation Example 5: Combustibility)
The combustibility of the electrolytic solution E4 and the electrolytic solution C2 was tested by the following method.
　電解液をガラスフィルターにピペットで３滴滴下し、電解液をガラスフィルターに保持させた。当該ガラスフィルターをピンセットで把持し、そして、当該ガラスフィルターに接炎させた。 3 drops of the electrolytic solution was dropped on the glass filter with a pipette, and the electrolytic solution was held on the glass filter. The glass filter was held with tweezers, and the glass filter was brought into contact with flame.
　電解液Ｅ４は１５秒間接炎させても引火しなかった。他方、電解液Ｃ２は５秒余りで燃え尽きた。 Electrolyte E4 did not ignite even after 15 seconds of indirect flame. On the other hand, the electrolytic solution C2 burned out in about 5 seconds.
　本発明の電解液は燃焼しにくいことが裏付けられた。 It was confirmed that the electrolytic solution of the present invention is difficult to burn.
（評価例６：Ｌｉ輸率）
　電解液Ｅ２、Ｅ８及び電解液Ｃ４、Ｃ５のＬｉ輸率を以下の条件で測定した。結果を表８に示す。 (Evaluation Example 6: Li transportation rate)
The Li transport numbers of the electrolytic solutions E2 and E8 and the electrolytic solutions C4 and C5 were measured under the following conditions. The results are shown in Table 8.
＜Ｌｉ輸率測定条件＞
　電解液Ｅ２、Ｅ８又は電解液Ｃ４、Ｃ５を入れたＮＭＲ管をＰＦＧ－ＮＭＲ装置（ＥＣＡ－５００、日本電子）に供し、７Ｌｉ、１９Ｆを対象として、スピンエコー法を用い、磁場パルス幅を変化させながら、各電解液中のＬｉイオン及びアニオンの拡散係数を測定した。Ｌｉ輸率は以下の式で算出した。
　Ｌｉ輸率＝（Ｌｉイオン拡散係数）／（Ｌｉイオン拡散係数＋アニオン拡散係数） <Li transport number measurement conditions>
The NMR tube containing the electrolytes E2 and E8 or the electrolytes C4 and C5 was supplied to a PFG-NMR apparatus (ECA-500, JEOL), and the magnetic field pulse width was applied to 7 Li and 19 F using the spin echo method. The diffusion coefficient of Li ions and anions in each electrolytic solution was measured while changing. The Li transport number was calculated by the following formula.
Li transport number = (Li ion diffusion coefficient) / (Li ion diffusion coefficient + anion diffusion coefficient)
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　電解液Ｅ２、Ｅ８のＬｉ輸率は、電解液Ｃ４、Ｃ５のＬｉ輸率と比較して、著しく高かった。ここで、電解液のＬｉイオン伝導度は、電解液に含まれるイオン伝導度（全イオン電導度）にＬｉ輸率を乗じて算出することができる。そうすると、本発明の電解液は、同程度のイオン伝導度を示す従来の電解液と比較して、リチウムイオン（カチオン）の輸送速度が高いといえる。 The Li transport number of the electrolytic solutions E2 and E8 was significantly higher than the Li transport number of the electrolytic solutions C4 and C5. Here, the Li ion conductivity of the electrolytic solution can be calculated by multiplying the ionic conductivity (total ionic conductivity) contained in the electrolytic solution by the Li transport number. If it does so, it can be said that the electrolyte solution of this invention has the high transport rate of lithium ion (cation) compared with the conventional electrolyte solution which shows comparable ionic conductivity.
　また、電解液Ｅ８の電解液につき、温度を変化させた場合のＬｉ輸率を、上記Ｌｉ輸率測定条件に準じて測定した。結果を表９に示す。 Further, for the electrolytic solution of the electrolytic solution E8, the Li transport number when the temperature was changed was measured according to the above Li transport number measurement conditions. The results are shown in Table 9.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　表９の結果から、本発明の電解液は、温度に因らず、好適なＬｉ輸率を保つことがわかる。本発明の電解液は、低温でも液体状態を保っているといえる。 From the results of Table 9, it can be seen that the electrolyte of the present invention maintains a suitable Li transport number regardless of the temperature. It can be said that the electrolytic solution of the present invention maintains a liquid state even at a low temperature.
（評価例７：低温試験）
　電解液Ｅ１１、電解液Ｅ１３、電解液Ｅ１６、電解液Ｅ１９をそれぞれ容器に入れ、不活性ガスを充填して密閉した。これらを－３０℃の冷凍庫に２日間保管した。保管後に各電解液を観察した。いずれの電解液も固化せず液体状態を維持しており、塩の析出も観察されなかった。 (Evaluation Example 7: Low temperature test)
Electrolytic solution E11, electrolytic solution E13, electrolytic solution E16, and electrolytic solution E19 were each put in a container, filled with an inert gas, and sealed. These were stored in a freezer at −30 ° C. for 2 days. Each electrolyte was observed after storage. None of the electrolytes were solidified and maintained in a liquid state, and no salt deposition was observed.
（評価例８：ラマンスペクトル測定）
　　電解液Ｅ８、Ｅ９、Ｃ４、Ｅ１１、Ｅ１３，Ｅ１５、Ｃ６につき、以下の条件でラマンスペクトル測定を行った。各電解液の金属塩のアニオン部分に由来するピークが観察されたラマンスペクトルをそれぞれ図２９～図３５に示す。図の横軸は波数（ｃｍ－１）であり、縦軸は散乱強度である。 (Evaluation Example 8: Raman spectrum measurement)
For the electrolytic solutions E8, E9, C4, E11, E13, E15, and C6, Raman spectrum measurement was performed under the following conditions. FIGS. 29 to 35 show Raman spectra in which peaks derived from the anion portion of the metal salt of each electrolytic solution were observed. In the figure, the horizontal axis represents the wave number (cm −1 ), and the vertical axis represents the scattering intensity.
　ラマンスペクトル測定条件
　装置：レーザーラマン分光光度計（日本分光株式会社ＮＲＳシリーズ）
　レーザー波長：５３２ｎｍ
　不活性ガス雰囲気下で電解液を石英セルに密閉し、測定に供した。 Raman spectrum measurement conditions Equipment: Laser Raman spectrophotometer (NRS series, JASCO Corporation)
Laser wavelength: 532 nm
The electrolyte was sealed in a quartz cell under an inert gas atmosphere and used for measurement.
　図２９～図３１で示される電解液Ｅ８、電解液Ｅ９、電解液Ｃ４のラマンスペクトルの７００～８００ｃｍ－１には、アセトニトリルに溶解したＬｉＦＳＡの（ＦＳＯ２）２Ｎに由来する特徴的なピークが観察された。ここで、図２９～図３５から、ＬｉＦＳＡの濃度の増加に伴い、上記ピークが高波数側にシフトするのがわかる。電解液が高濃度化するに従い、塩のアニオンに該当する（ＦＳＯ２）２Ｎが、より多くのＬｉと相互作用する状態になると推察される。そして、かかる状態がラマンスペクトルのピークシフトとして観察されたと考察できる。 Electrolyte E8 shown in FIGS. 29 to 31, the electrolytic solution E9, the 700 ~ 800 cm -1 in the Raman spectrum of the electrolyte C4, characteristic peaks derived from (FSO 2) 2 N of LiFSA in acetonitrile Was observed. Here, it can be seen from FIGS. 29 to 35 that the peak shifts to the higher wavenumber side as the LiFSA concentration increases. It is presumed that (FSO 2 ) 2 N corresponding to the anion of the salt interacts with more Li as the electrolyte concentration increases. It can be considered that such a state was observed as a peak shift of the Raman spectrum.
　図３２～図３５で示される電解液Ｅ１１，Ｅ１３、Ｅ１５、Ｃ６のラマンスペクトルの７００～８００ｃｍ－１には、ジメチルカーボネートに溶解したＬｉＦＳＡの（ＦＳＯ２）２Ｎに由来する特徴的なピークが観察された。ここで、図３２～図３５から、ＬｉＦＳＡの濃度の増加に伴い、上記ピークが高波数側にシフトするのがわかる。この現象は、前段落で考察したのと同様に、電解液が高濃度化することで、塩のアニオンに該当する（ＦＳＯ２）２Ｎが複数のＬｉと相互作用している状態がスペクトルに反映された結果である、言い換えると濃度が低い場合はＬｉとアニオンはSSIP(Solvent-separeted ion pairs)状態を主に形成しており、高濃度化に伴いCIP(contact ion pairs)状態やAGG(aggregate)状態を主に形成していると推察される。そして、かかる状態の変化がラマンスペクトルのピークシフトとして観察されたと考察できる。 A characteristic peak derived from (FSO 2 ) 2 N of LiFSA dissolved in dimethyl carbonate is observed in 700 to 800 cm −1 of the Raman spectra of the electrolytic solutions E11, E13, E15, and C6 shown in FIGS. Observed. Here, it can be seen from FIGS. 32 to 35 that the peak shifts to the higher wavenumber side as the concentration of LiFSA increases. This phenomenon is similar to that discussed in the previous paragraph. When the concentration of the electrolyte is increased, the state in which (FSO 2 ) 2 N corresponding to the anion of the salt interacts with a plurality of Li is shown in the spectrum. In other words, when the concentration is low, Li and anions mainly form SSIP (Solvent-separeted ion pairs) state, and CIP (contact ion pairs) state and AGG ( It is presumed that the aggregate) state is mainly formed. It can be considered that such a change in the state was observed as a peak shift of the Raman spectrum.
（実施例Ａ－１）
　実施例Ａ－１のリチウムイオン二次電池は、正極と負極と電解液とセパレータとを有する。 Example A-1
The lithium ion secondary battery of Example A-1 has a positive electrode, a negative electrode, an electrolytic solution, and a separator.
　正極は、正極活物質層と、正極活物質層で被覆された集電体とからなる。正極活物質層は、正極活物質と、結着剤と、導電助剤とを有する。正極活物質は、ＬｉＮｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２で表される層状岩塩構造のリチウム含有金属酸化物からなる。結着剤は、ポリフッ化ビニリデン（ＰＶＤＦ）からなる。導電助剤は、アセチレンブラック（ＡＢ）からなる。集電体は、厚み２０μｍのアルミニウム箔からなる。正極活物質層を１００質量部としたときの、正極活物質と結着剤と導電助剤との含有質量比は、９４：３：３である。 The positive electrode includes a positive electrode active material layer and a current collector covered with the positive electrode active material layer. The positive electrode active material layer has a positive electrode active material, a binder, and a conductive additive. The positive electrode active material is composed of a lithium-containing metal oxide having a layered rock salt structure represented by LiNi 0.5 Co 0.2 Mn 0.3 O 2 . The binder is made of polyvinylidene fluoride (PVDF). The conductive auxiliary agent is made of acetylene black (AB). The current collector is made of an aluminum foil having a thickness of 20 μm. When the positive electrode active material layer is 100 parts by mass, the mass ratio of the positive electrode active material, the binder, and the conductive additive is 94: 3: 3.
　正極を作製するために、ＬｉＮｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２、ＰＶＤＦ及びＡＢを上記の質量比となるように混合し、溶剤としてのＮ－メチル－２－ピロリドン（ＮＭＰ）を添加してペースト状の正極材とする。ペースト状の正極材を、集電体の表面にドクターブレードを用いて塗布して、正極活物質層を形成した。正極活物質層を、８０℃で２０分間乾燥することで、ＮＭＰを揮発により除去した。表面に正極活物質層を形成したアルミニウム箔を、ロ－ルプレス機を用いて圧縮し、アルミニウム箔と正極活物質層とを強固に密着接合させた。接合物を１２０℃で６時間、真空乾燥機で加熱し、所定の形状に切り取り、正極を得た。以下、必要に応じて、ＬｉＮｉ５／１０Ｃｏ２／１０Ｍｎ３／１０Ｏ２で表される層状岩塩構造のリチウム含有金属酸化物をＮＣＭ５２３と略し、アセチレンブラックをＡＢと略し、ポリフッ化ビニリデンをＰＶｄＦと略する。 In order to produce a positive electrode, LiNi 0.5 Co 0.2 Mn 0.3 O 2 , PVDF and AB are mixed so as to have the above mass ratio, and N-methyl-2-pyrrolidone (NMP) as a solvent is mixed. To obtain a paste-like positive electrode material. The paste-like positive electrode material was applied to the surface of the current collector using a doctor blade to form a positive electrode active material layer. The positive electrode active material layer was dried at 80 ° C. for 20 minutes to remove NMP by volatilization. The aluminum foil having the positive electrode active material layer formed on the surface thereof was compressed using a roll press, and the aluminum foil and the positive electrode active material layer were firmly bonded. The joined product was heated in a vacuum dryer at 120 ° C. for 6 hours, cut into a predetermined shape, and a positive electrode was obtained. Hereinafter, as necessary, a lithium-containing metal oxide having a layered rock salt structure represented by LiNi 5/10 Co 2/10 Mn 3/10 O 2 is abbreviated as NCM523, acetylene black is abbreviated as AB, and polyvinylidene fluoride is abbreviated. Abbreviated as PVdF.
　負極は、負極活物質層と、負極活物質層で被覆された集電体とからなる。負極活物質層は、負極活物質と、結着剤とを有する。負極を作製するために、負極活物質としての黒鉛９８質量部と、結着剤としてスチレン－ブタジエンゴム（ＳＢＲ）１質量部及びカルボキシメチルセルロース（ＣＭＣ）１質量部とを混合した。この混合物を適量のイオン交換水に分散させてスラリー状の負極材を作製した。このスラリー状の負極材を負極用集電体である厚み２０μｍの銅箔にドクターブレードを用いて膜状になるように塗布して負極活物質層を形成した。負極活物質層を形成した集電体を乾燥後プレスし、接合物を１００℃で６時間、真空乾燥機で加熱し、所定の形状に切り取り、負極とした。 The negative electrode is composed of a negative electrode active material layer and a current collector coated with the negative electrode active material layer. The negative electrode active material layer has a negative electrode active material and a binder. In order to produce a negative electrode, 98 parts by mass of graphite as a negative electrode active material and 1 part by mass of styrene-butadiene rubber (SBR) and 1 part by mass of carboxymethyl cellulose (CMC) as a binder were mixed. This mixture was dispersed in an appropriate amount of ion-exchanged water to prepare a slurry-like negative electrode material. The slurry-like negative electrode material was applied to a copper foil having a thickness of 20 μm, which is a negative electrode current collector, in a film shape using a doctor blade to form a negative electrode active material layer. The current collector on which the negative electrode active material layer was formed was dried and pressed, and the bonded product was heated with a vacuum dryer at 100 ° C. for 6 hours, cut into a predetermined shape, and used as a negative electrode.
　実施例Ａ－１の電解液として、上記の電解液Ｅ８を用いた。 The above electrolytic solution E8 was used as the electrolytic solution of Example A-1.
　上記の正極、負極及び電解液を用いて、ラミネート型リチウムイオン二次電池を製作した。詳しくは、正極および負極の間に、セパレータとしてセルロース不織布（東洋濾紙株式会社製ろ紙（セルロース、厚み２６０μｍ））を挟装して極板群とした。この極板群を二枚一組のラミネートフィルムで覆い、三辺をシールした後、袋状となったラミネートフィルムに上記電解液を注入した。その後、残りの一辺をシールすることで、四辺が気密にシールされ、極板群および電解液が密閉されたラミネート型リチウムイオン二次電池を得た。なお、正極および負極は外部と電気的に接続可能なタブを備え、このタブの一部はラミネート型リチウムイオン二次電池の外側に延出している。 A laminated lithium ion secondary battery was manufactured using the positive electrode, the negative electrode, and the electrolytic solution. Specifically, a cellulose nonwoven fabric (Toyo Filter Paper Co., Ltd. filter paper (cellulose, thickness 260 μm)) was sandwiched between the positive electrode and the negative electrode to form an electrode plate group. The electrode plate group was covered with a set of two laminated films, and the three sides were sealed, and then the electrolyte solution was poured into the bag-like laminated film. Thereafter, the remaining one side was sealed to obtain a laminate type lithium ion secondary battery in which the four sides were hermetically sealed and the electrode plate group and the electrolyte were sealed. Note that the positive electrode and the negative electrode have a tab that can be electrically connected to the outside, and a part of the tab extends to the outside of the laminated lithium ion secondary battery.
（実施例Ａ－２）
　実施例Ａ－２のリチウムイオン二次電池は、電解液として上記の電解液Ｅ４を用いた点を除いて、実施例Ａ－１と同様である。 Example A-2
The lithium ion secondary battery of Example A-2 is the same as Example A-1 except that the above-described electrolytic solution E4 is used as the electrolytic solution.
（実施例Ａ－３）
　実施例Ａ－３のリチウムイオン二次電池は、電解液として電解液Ｅ１を用いた点を除いて、実施例Ａ－１と同様である。 Example A-3
The lithium ion secondary battery of Example A-3 is the same as Example A-1 except that the electrolytic solution E1 is used as the electrolytic solution.
（実施例Ａ－４）
　実施例Ａ－４のリチウムイオン二次電池は、以下のとおり製造した。 Example A-4
The lithium ion secondary battery of Example A-4 was manufactured as follows.
　正極は、実施例Ａ－１のリチウムイオン二次電池の正極と同様に製造した。 The positive electrode was produced in the same manner as the positive electrode of the lithium ion secondary battery of Example A-1.
　負極活物質である天然黒鉛９０質量部、及び結着剤であるポリフッ化ビニリデン１０質量部を混合した。この混合物を適量のイオン交換水に分散させて、スラリーを作製した。負極集電体として厚み２０μｍの銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を乾燥して水を除去し、その後、銅箔をプレスし、接合物を得た。得られた接合物を真空乾燥機で１２０℃、６時間加熱乾燥して、負極活物質層が形成された銅箔を得た。これを負極とした。 90 parts by mass of natural graphite as a negative electrode active material and 10 parts by mass of polyvinylidene fluoride as a binder were mixed. This mixture was dispersed in an appropriate amount of ion-exchanged water to prepare a slurry. A copper foil having a thickness of 20 μm was prepared as a negative electrode current collector. The slurry was applied in a film form on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried to remove water, and then the copper foil was pressed to obtain a bonded product. The obtained joined product was heat-dried at 120 ° C. for 6 hours with a vacuum dryer to obtain a copper foil on which a negative electrode active material layer was formed. This was used as a negative electrode.
　セパレータとして、厚さ２０μｍのセルロース製不織布を準備した。 A cellulose nonwoven fabric having a thickness of 20 μm was prepared as a separator.
　正極と負極とでセパレータを挟持し、極板群とした。この極板群を二枚一組のラミネートフィルムで覆い、三辺をシールした後、袋状となったラミネートフィルムに実施例Ａ－１で用いた電解液Ｅ８を注入した。その後、残りの一辺をシールすることで、四辺が気密にシールされ、極板群および電解液が密閉されたリチウムイオン二次電池を得た。この電池を実施例Ａ－４のリチウムイオン二次電池とした。 A separator was sandwiched between the positive electrode and the negative electrode to form an electrode plate group. The electrode plate group was covered with a set of two laminated films, and the three sides were sealed. Then, the electrolyte solution E8 used in Example A-1 was poured into the bag-like laminated film. Thereafter, the remaining one side was sealed to obtain a lithium ion secondary battery in which the four sides were hermetically sealed and the electrode plate group and the electrolyte were sealed. This battery was designated as the lithium ion secondary battery of Example A-4.
（比較例Ａ－１）
　比較例Ａ－１のリチウムイオン二次電池は、電解液として上記の電解液Ｃ５を用いた点を除いて、実施例Ａ－１と同様である。 (Comparative Example A-1)
The lithium ion secondary battery of Comparative Example A-1 is the same as Example A-1 except that the above electrolytic solution C5 was used as the electrolytic solution.
（比較例Ａ－２）
　比較例Ａ－２のリチウムイオン二次電池は、比較例Ａ－１で用いた電解液Ｃ５を用いた以外は、実施例Ａ－４と同様である。 (Comparative Example A-2)
The lithium ion secondary battery of Comparative Example A-2 is the same as Example A-4 except that the electrolytic solution C5 used in Comparative Example A-1 was used.
　表１０に実施例Ａ－１、Ａ－２、Ａ－３、Ａ－４及び比較例Ａ－１、Ａ－２の電解液の一覧を示す。 Table 10 shows a list of electrolytic solutions of Examples A-1, A-2, A-3, A-4 and Comparative Examples A-1, A-2.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　（評価例Ａ－９：入出力特性）
（１）０℃、ＳＯＣ２０％での出力特性評価
　上記の実施例Ａ－１及び比較例Ａ－１のリチウムイオン二次電池の出力特性を評価した。評価に供した実施例Ａ－１及び比較例Ａ－１のリチウムイオン二次電池の正極の目付は１１ｍｇ／ｃｍ２であり、負極の目付は８ｍｇ／ｃｍ２である。評価条件は、充電状態（ＳＯＣ）２０％、０℃、使用電圧範囲３Ｖ―４．２Ｖ、容量１３．５ｍＡｈである。ＳＯＣ２０％、０℃は、例えば、冷蔵室などで使用する場合のように出力特性が出にくい領域である。実施例Ａ－１及び比較例Ａ－１の出力特性の評価は、それぞれ２秒出力と５秒出力についてそれぞれ３回行った。出力特性の評価結果を表１１に示した。表１１の中の「２秒出力」は、放電開始から２秒後での出力を意味し、「５秒出力」は放電開始から５秒後での出力を意味している。 (Evaluation example A-9: Input / output characteristics)
(1) Evaluation of output characteristics at 0 ° C. and SOC 20% The output characteristics of the lithium ion secondary batteries of Example A-1 and Comparative Example A-1 were evaluated. The basis weight of the positive electrode of the lithium ion secondary batteries of Example A-1 and Comparative Example A-1 used for evaluation is 11 mg / cm 2 , and the basis weight of the negative electrode is 8 mg / cm 2 . The evaluation conditions are a state of charge (SOC) of 20%, 0 ° C., a working voltage range of 3 V to 4.2 V, and a capacity of 13.5 mAh. SOC 20%, 0 ° C. is a region where output characteristics are difficult to be obtained, for example, when used in a refrigerator room. The output characteristics of Example A-1 and Comparative Example A-1 were evaluated three times for each of the 2-second output and 5-second output. The evaluation results of the output characteristics are shown in Table 11. In Table 11, “2 seconds output” means an output 2 seconds after the start of discharge, and “5 seconds output” means an output 5 seconds after the start of discharge.
　表１１に示すように、実施例Ａ－１の電池の０℃、ＳＯＣ２０％の出力は、比較例Ａ－１の電池の出力に比べて、１．２～１．３倍高かった。 As shown in Table 11, the output of the battery of Example A-1 at 0 ° C. and SOC 20% was 1.2 to 1.3 times higher than the output of the battery of Comparative Example A-1.
（２）２５℃、ＳＯＣ２０％での出力特性評価
　上記の実施例Ａ－１及び比較例Ａ－１の電池の出力特性を、充電状態（ＳＯＣ）２０％、２５℃、使用電圧範囲３Ｖ―４．２Ｖ、容量１３．５ｍＡｈの条件で評価した。実施例Ａ－１及び比較例Ａ－１の出力特性の評価は、それぞれ２秒出力と５秒出力についてそれぞれ３回行った。評価結果を表１１に示した。 (2) Evaluation of output characteristics at 25 ° C. and SOC 20% The output characteristics of the batteries of Example A-1 and Comparative Example A-1 are as follows: charge state (SOC) 20%, 25 ° C., operating voltage range 3V-4 Evaluation was performed under the conditions of 0.2 V and a capacity of 13.5 mAh. The output characteristics of Example A-1 and Comparative Example A-1 were evaluated three times for each of the 2-second output and 5-second output. The evaluation results are shown in Table 11.
　表１１に示すように、実施例Ａ－１の電池の２５℃、ＳＯＣ２０％の出力は、比較例Ａ－１の電池の出力に比べて、１．２～１．３倍高かった。 As shown in Table 11, the output of the battery of Example A-1 at 25 ° C. and SOC 20% was 1.2 to 1.3 times higher than the output of the battery of Comparative Example A-1.
（３）出力特性に対する温度の影響
　上記の実施例Ａ－１及び比較例Ａ－１のリチウムイオン二次電池の出力特性に対する、測定時の温度の影響を調べた。０℃と２５℃で測定し、いずれの温度下での測定においても、評価条件は、充電状態（ＳＯＣ）２０％、使用電圧範囲３Ｖ―４．２Ｖ、容量１３．５ｍＡｈとした。２５℃での出力に対する０℃での出力の比率（０℃出力／２５℃出力）をもとめた。その結果を表１１に示した。 (3) Effect of temperature on output characteristics The influence of temperature during measurement on the output characteristics of the lithium ion secondary batteries of Example A-1 and Comparative Example A-1 was examined. Measurement was performed at 0 ° C. and 25 ° C., and in any measurement, the evaluation conditions were a state of charge (SOC) of 20%, a working voltage range of 3 V to 4.2 V, and a capacity of 13.5 mAh. The ratio of the output at 0 ° C. to the output at 25 ° C. (0 ° C. output / 25 ° C. output) was determined. The results are shown in Table 11.
　表１１に示すように、実施例Ａ－１の電解液は、比較例Ａ－１の電解液と同程度に低温での出力低下を抑制できることがわかった。 As shown in Table 11, it was found that the electrolyte solution of Example A-1 can suppress a decrease in output at a low temperature to the same extent as the electrolyte solution of Comparative Example A-1.
　また、実施例Ａ－１の電解液では、ヘテロ元素を有する有機溶媒アセトニトリルの大半がリチウム塩ＬＩＦＳＡとクラスターを形成していることから、電解液に含まれる有機溶媒の蒸気圧が低くなる。その結果として、電解液からの有機溶媒の揮発が低減できる。 Further, in the electrolyte solution of Example A-1, since most of the organic solvent acetonitrile having the hetero element forms a cluster with the lithium salt LIFSA, the vapor pressure of the organic solvent contained in the electrolyte solution becomes low. As a result, volatilization of the organic solvent from the electrolytic solution can be reduced.
　これに対して、比較例Ａ－１では、ＥＣ系溶媒を用いている。ＥＣは、電解液の粘度及び融点を下げるために混合される。比較例Ａ－１の溶媒には、鎖状カーボネートであるＤＥＣも含まれている。鎖状カーボネートは、揮発し易く、万が一、電池に隙間が有った場合や損傷などが発生した場合には、系外に瞬時に大量の有機溶媒が気体として放出されるおそれがある。 On the other hand, in Comparative Example A-1, an EC solvent is used. EC is mixed to reduce the viscosity and melting point of the electrolyte. The solvent of Comparative Example A-1 also contains DEC, which is a chain carbonate. The chain carbonate is easy to volatilize, and if there is a gap in the battery or damage occurs, a large amount of organic solvent may be instantaneously released out of the system as a gas.
　電解液の溶媒として、イオン液体のような低揮発性液体を用いることにより、比較例Ａ－１の電解液の課題を解決することはできる。しかし、イオン液体は、粘度が高く、イオン伝導度が通常の電解液と比較して低いため、入出力特性が悪くなると予想される。この傾向は、０℃などの低温で顕著であり、０℃出力／２５℃出力が０．２以下になると予想される。 By using a low-volatile liquid such as an ionic liquid as the solvent of the electrolytic solution, the problem of the electrolytic solution of Comparative Example A-1 can be solved. However, since the ionic liquid has a high viscosity and a low ionic conductivity as compared with a normal electrolytic solution, the input / output characteristics are expected to deteriorate. This tendency is remarkable at a low temperature such as 0 ° C., and the 0 ° C. output / 25 ° C. output is expected to be 0.2 or less.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
（４）０℃又は２５℃、ＳＯＣ８０％での入力特性評価
　リチウムイオン二次電池の入力特性を評価した。本評価で用いた電池は、セパレータとして厚み２０μｍのセルロース不織布を用いた点を除いて、実施例Ａ－１、実施例Ａ－４、比較例Ａ－１，比較例Ａ－２のリチウムイオン二次電池と同様である。実施例Ａ－１，Ａ－４、比較例Ａ－１，Ａ－２に対応する電池を、順に実施電池Ａ－１、実施電池Ａ－４、比較電池Ａ－１，比較電池Ａ－２とした。評価条件は、充電状態（ＳＯＣ）８０％、０℃又は２５℃、使用電圧範囲３Ｖ―４．２Ｖ、容量１３．５ｍＡｈとした。入力特性の評価は、２秒入力と５秒入力について電池毎にそれぞれ３回行った。 (4) Evaluation of input characteristics at 0 ° C. or 25 ° C. and SOC 80% The input characteristics of the lithium ion secondary battery were evaluated. The batteries used in this evaluation were the lithium ion batteries of Example A-1, Example A-4, Comparative Example A-1, and Comparative Example A-2, except that a cellulose nonwoven fabric having a thickness of 20 μm was used as a separator. It is the same as the secondary battery. The batteries corresponding to Examples A-1 and A-4 and Comparative Examples A-1 and A-2 are, in order, the implementation battery A-1, the implementation battery A-4, the comparison battery A-1, and the comparison battery A-2. did. The evaluation conditions were a state of charge (SOC) of 80%, 0 ° C. or 25 ° C., a working voltage range of 3 V to 4.2 V, and a capacity of 13.5 mAh. The input characteristics were evaluated three times for each battery for a 2-second input and a 5-second input.
　また、各電池の体積に基づき、２５℃、２秒入力における電池出力密度（Ｗ／Ｌ）を算出した。入力特性の評価結果を表１２に示す。 Also, based on the volume of each battery, the battery output density (W / L) at 25 ° C. for 2 seconds was calculated. Table 12 shows the evaluation results of the input characteristics.
　表１２に示すように、温度の違いに関わらず、実施電池Ａ－１の電池の入力は、比較電池Ａ－１の電池の入力に比べて、著しく高かった。同様に、実施電池Ａ－４の電池の入力は、比較電池Ａ－２の電池の入力に比べて、著しく高かった。 As shown in Table 12, regardless of the difference in temperature, the input of the battery of the implementation battery A-1 was significantly higher than the input of the battery of the comparative battery A-1. Similarly, the input of the battery of Example battery A-4 was significantly higher than the input of the battery of comparative battery A-2.
　また、実施電池Ａ－１の電池入力密度は、比較電池Ａ－１の電池入力密度に比べて、著しく高かった。同様に、実施電池Ａ－４の電池入力密度は、比較電池Ａ－２の電池入力密度に比べて、著しく高かった。 In addition, the battery input density of the implementation battery A-1 was significantly higher than the battery input density of the comparative battery A-1. Similarly, the battery input density of Example Battery A-4 was significantly higher than the battery input density of Comparative Battery A-2.
（５）０℃又は２５℃、ＳＯＣ２０％での出力特性評価
　実施電池Ａ－１、実施電池Ａ－４、比較電池Ａ－１、比較電池Ａ－２の出力特性を以下の条件で評価した。評価条件は、充電状態（ＳＯＣ）２０％、０℃又は２５℃、使用電圧範囲３Ｖ―４．２Ｖ、容量１３．５ｍＡｈとした。ＳＯＣ２０％、０℃は、例えば、冷蔵室などで使用する場合のように出力特性が出にくい領域である。出力特性の評価は、２秒出力と５秒出力について電池毎にそれぞれ３回行った。 (5) Evaluation of output characteristics at 0 ° C. or 25 ° C. and SOC 20% The output characteristics of Example Battery A-1, Example Battery A-4, Comparison Battery A-1, and Comparison Battery A-2 were evaluated under the following conditions. The evaluation conditions were a state of charge (SOC) of 20%, 0 ° C. or 25 ° C., a working voltage range of 3 V to 4.2 V, and a capacity of 13.5 mAh. SOC 20%, 0 ° C. is a region where output characteristics are difficult to be obtained, for example, when used in a refrigerator room. The output characteristics were evaluated three times for each battery for the 2-second output and 5-second output.
　また、各電池の体積に基づき、２５℃、２秒出力における電池出力密度（Ｗ／Ｌ）を算出した。出力特性の評価結果を表１２に示す。 Also, based on the volume of each battery, the battery output density (W / L) at 25 ° C. for 2 seconds output was calculated. Table 12 shows the evaluation results of the output characteristics.
　表１２に示すように、温度の違いに関わらず、実施電池Ａ－１の出力は、比較電池Ａ－１の出力に比べて、著しく高かった。同様に、実施電池Ａ－４の出力は、比較電池Ａ－２の出力に比べて、著しく高かった。 As shown in Table 12, the output of the implementation battery A-1 was remarkably higher than the output of the comparison battery A-1 regardless of the difference in temperature. Similarly, the output of Example Battery A-4 was significantly higher than the output of Comparative Battery A-2.
　また、実施電池Ａ－１の電池出力密度は、比較電池Ａ－１の電池出力密度に比べて、著しく高かった。同様に、実施電池Ａ－４の電池出力密度は、比較電池Ａ－２の電池出力密度に比べて、著しく高かった。 Further, the battery output density of the implementation battery A-1 was significantly higher than the battery output density of the comparative battery A-1. Similarly, the battery output density of Example Battery A-4 was significantly higher than that of Comparative Battery A-2.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
（評価例Ａ－１０：ＤＳＣ試験）
　実施例Ａ－１、実施例Ａ－２及び比較例Ａ－１の電池の中の正極と電解液の熱物性試験を行った。 (Evaluation example A-10: DSC test)
The thermophysical property test of the positive electrode and the electrolyte in the batteries of Example A-1, Example A-2, and Comparative Example A-1 was performed.
　各電池に対し、充電終始電圧４．２Ｖ、定電流定電圧条件で満充電した。満充電後のリチウムイオン二次電池を解体し、正極を取り出した。当該正極３ｍｇ及び電解液１．８μＬをステンレス製のパンに入れ、該パンを密閉した。密閉パンを用いて、窒素雰囲気下、昇温速度２０℃／ｍｉｎ．の条件で示差走査熱量分析を行い、ＤＳＣ曲線を観察した。示差走査熱量測定装置としてＲｉｇａｋｕ　ＤＳＣ８２３０を使用した。実施例Ａ－１と比較例Ａ－１の測定結果を図３６に示し、実施例Ａ－２と比較例Ａ－１の測定結果を図３７に示した。 Each battery was fully charged under the constant charging and constant voltage conditions of 4.2V at the beginning of charging. The fully charged lithium ion secondary battery was disassembled and the positive electrode was taken out. 3 mg of the positive electrode and 1.8 μL of the electrolytic solution were placed in a stainless steel pan, and the pan was sealed. Using a sealed pan, under a nitrogen atmosphere, the heating rate was 20 ° C / min. The differential scanning calorimetry was performed under the conditions described above, and the DSC curve was observed. A Rigaku DSC8230 was used as a differential scanning calorimeter. The measurement results of Example A-1 and Comparative Example A-1 are shown in FIG. 36, and the measurement results of Example A-2 and Comparative Example A-1 are shown in FIG.
　図３６、図３７に示すように、実施例Ａ－１では３００℃付近での発熱が生じなかったが、比較例Ａ－１では、３００℃付近で発熱が生じた。実施例Ａ－１の電池では、充電中での電解液と正極活物質との反応性が低く、熱物性に優れていることがわかった。 As shown in FIGS. 36 and 37, Example A-1 did not generate heat near 300 ° C., but Comparative Example A-1 generated heat near 300 ° C. In the battery of Example A-1, it was found that the reactivity between the electrolyte during charging and the positive electrode active material was low, and the thermophysical properties were excellent.
　実施例Ａ－１の電解液では、ヘテロ元素を有する有機溶媒アセトニトリルの大半がリチウム塩ＬＩＦＳＡとクラスターを形成していることから、電解液に含まれる有機溶媒の蒸気圧が低くなる。その結果として、電解液からの有機溶媒の揮発が低減できる。また、溶媒量が通常に比べて少ないため、燃焼した場合の潜在的な熱量が少ない。更に、電解液自身が正極から放出される酸素との反応性が乏しいため、熱物性に優れていると考えられる。 In the electrolytic solution of Example A-1, since most of the organic solvent acetonitrile having a hetero element forms a cluster with the lithium salt LIFSA, the vapor pressure of the organic solvent contained in the electrolytic solution is lowered. As a result, volatilization of the organic solvent from the electrolytic solution can be reduced. In addition, since the amount of solvent is smaller than usual, the amount of potential heat when burned is small. Furthermore, since the electrolyte solution itself has poor reactivity with oxygen released from the positive electrode, it is considered that the thermophysical property is excellent.
　比較例Ａ－１の３００℃付近での発熱は、電解液と正極との反応であり、特に正極から発生した酸素と電解液との反応であると考えられる。 The heat generation in the vicinity of 300 ° C. in Comparative Example A-1 is considered to be a reaction between the electrolytic solution and the positive electrode, particularly a reaction between oxygen generated from the positive electrode and the electrolytic solution.
　図３７に示すように、実施例Ａ－２の電解液は、比較例Ａ－１の電解液に比べて、発熱量が極めて少なかった。実施例Ａ－２の電解液も、ＬｉＴＦＳＡのＬｉイオンと溶媒分子とが相互的な静電引力で引き合っているため、フリーの溶媒分子が存在せず、揮発しにくくなっている。また、充電時に正極活物質と反応しにくい。このため、実施例Ａ－２の電池は熱物性に優れていると考えられる。 As shown in FIG. 37, the electrolyte solution of Example A-2 generated a very small amount of heat as compared with the electrolyte solution of Comparative Example A-1. In the electrolyte solution of Example A-2, since LiTFSA Li ions and solvent molecules attract each other by mutual electrostatic attraction, free solvent molecules do not exist and are difficult to volatilize. In addition, it hardly reacts with the positive electrode active material during charging. For this reason, the battery of Example A-2 is considered to have excellent thermophysical properties.
（評価例Ａ－１１：レート容量特性の評価）
　実施例Ａ－１及び比較例Ａ－１のレート容量特性を評価した。各電池の容量は、１６０ｍＡｈ／ｇとなるように調整した。評価条件は、０．１Ｃ、０．２Ｃ、０．５Ｃ、１Ｃ、２Ｃの速度で充電を行った後に放電を行い、それぞれの速度における正極の容量（放電容量）を測定した。１Ｃは、一定電流において１時間で電池を完全充電、又は放電させるために要する電流値を示す。０．１Ｃ放電後及び１Ｃ放電後の放電容量を表１３に示した。表１３に示した放電容量は、正極重量当たりの容量の算出値である。 (Evaluation Example A-11: Evaluation of rate capacity characteristics)
The rate capacity characteristics of Example A-1 and Comparative Example A-1 were evaluated. The capacity of each battery was adjusted to 160 mAh / g. As evaluation conditions, after charging at a rate of 0.1 C, 0.2 C, 0.5 C, 1 C, and 2 C, discharging was performed, and the capacity (discharge capacity) of the positive electrode at each rate was measured. 1C indicates a current value required to fully charge or discharge the battery in one hour at a constant current. Table 13 shows the discharge capacity after 0.1 C discharge and after 1 C discharge. The discharge capacity shown in Table 13 is a calculated value of capacity per positive electrode weight.
　表１３に示すように、０．１Ｃ放電容量は実施例Ａ－１と比較例Ａ－１とで大差がなかったが、１Ｃ放電容量は実施例Ａ－１の方が比較例Ａ－１よりも大きかった。 As shown in Table 13, the 0.1 C discharge capacity was not significantly different between Example A-1 and Comparative Example A-1, but the 1 C discharge capacity was greater in Example A-1 than in Comparative Example A-1. Was also big.
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
(実施例Ａ－５)
　実施例Ａ－５のリチウムイオン二次電池の電解液は、電解液Ｅ１１を用いた。実施例Ａ－５のリチウムイオン二次電池の正極、負極、及びセパレータは、実施電池Ａ－１（セパレータ厚み２０μｍ）と同様のものを用いた。 Example A-5
The electrolyte solution E11 was used as the electrolyte solution of the lithium ion secondary battery of Example A-5. The positive electrode, negative electrode, and separator of the lithium ion secondary battery of Example A-5 were the same as those of Example Battery A-1 (separator thickness 20 μm).
（比較例Ａ－３）
　比較例Ａ－３のリチウムイオン二次電池の正極、負極、セパレータ及び電解液は、比較電池Ａ－１のそれらと同様である。 (Comparative Example A-3)
The positive electrode, negative electrode, separator and electrolyte of the lithium ion secondary battery of Comparative Example A-3 are the same as those of Comparative Battery A-1.
（評価例Ａ－１２：容量維持率）
　実施例Ａ－５、比較例Ａ－３のリチウム二次電池を用い、それぞれ温度２５℃、１ＣのＣＣ充電の条件下において４．１Ｖまで充電し、１分間休止した後、１ＣのＣＣ放電で３．０Ｖまで放電し、１分間休止するサイクルを５００サイクル繰り返すサイクル試験を行った。各サイクルにおける放電容量維持率を測定し、結果を図３８に示した。５００サイクル目における放電容量維持率を表１４に示した。放電容量維持率は、各サイクルの放電容量を初回の放電容量で除した値の百分率（（各サイクルの放電容量）／（初回の放電容量）×１００）で求められる値である。 (Evaluation Example A-12: Capacity maintenance rate)
Using the lithium secondary batteries of Example A-5 and Comparative Example A-3, charging to 4.1 V under conditions of CC charging at a temperature of 25 ° C. and 1 C, and resting for 1 minute, followed by 1 C CC discharging A cycle test was performed in which a cycle of discharging to 3.0 V and resting for 1 minute was repeated 500 times. The discharge capacity retention ratio in each cycle was measured, and the results are shown in FIG. Table 14 shows the discharge capacity retention ratio at the 500th cycle. The discharge capacity maintenance ratio is a value obtained by a percentage ((discharge capacity of each cycle) / (initial discharge capacity) × 100) obtained by dividing the discharge capacity of each cycle by the initial discharge capacity.
　表１４及び図３８に示すように、実施例Ａ－５のように電解液の溶媒としてＤＭＣを用いると、サイクル寿命が向上した。 As shown in Table 14 and FIG. 38, when DMC was used as the solvent of the electrolytic solution as in Example A-5, the cycle life was improved.
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　また初期及び200サイクル目において、温度25℃、0.5CのCCCVで電圧3.5Vに調整した後、3Cで10秒のCC放電をした際の電圧変化量（放電前電圧と放電10秒後電圧との差）及び電流値からオームの法則により直流抵抗（放電）を測定した。 In the initial and 200th cycle, after adjusting the voltage to 3.5V with CCCV at 25C and 0.5C, the amount of voltage change when the CC discharge for 10 seconds at 3C (voltage before discharge and voltage after 10 seconds after discharge) DC resistance (discharge) was measured according to Ohm's law from the difference in current and current value.
　さらに初期及び200サイクル目において、温度25℃、0.5CのCCCVで電圧3.5Vに調整した後、3Cで10秒のCC充電をした際の電圧変化量（充電前電圧と充電10秒後電圧との差）及び電流値からオームの法則により直流抵抗（充電）を測定した。それぞれの結果を表１５に示す。 Furthermore, at the initial stage and the 200th cycle, after adjusting the voltage to 3.5V with a CCCV of 0.5C at a temperature of 25 ° C, the amount of voltage change when charging the CC for 10 seconds at 3C (the voltage before charging and the voltage after 10 seconds after charging) DC resistance (charging) was measured according to Ohm's law. The results are shown in Table 15.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
　実施例Ａ－５のリチウム二次電池は、サイクル後においても抵抗が小さいことがわかる。また実施例Ａ－５のリチウム二次電池は、容量維持率が高く、劣化しにくいといえる。 It can be seen that the lithium secondary battery of Example A-5 has low resistance even after cycling. Further, it can be said that the lithium secondary battery of Example A-5 has a high capacity retention rate and is hardly deteriorated.
（評価例Ａ－１３：Ｎｉ、Ｍｎ、Ｃｏの溶出確認）
　実施例Ａ－５及び比較例Ａ－３のリチウムイオン二次電池を、使用電圧範囲３Ｖ～４．１Ｖとし、レート１Ｃで充放電を５００回繰り返した。充放電５００回後に各電池を解体し、負極を取り出した。正極から電解液に溶出し、負極の表面へ沈着したＮｉ、Ｍｎ、Ｃｏの量をＩＣＰ（高周波誘導結合プラズマ）発光分光分析装置で測定した。測定結果を表１６に示す。表１６のＮｉ、Ｍｎ、Ｃｏ量（質量％）は負極活物質層１ｇあたりのＮｉ、Ｍｎ、Ｃｏの質量を％で示したものであり、Ｎｉ、Ｍｎ、Ｃｏ量（μｇ／枚）は、負極活物質層１枚当たりのＮｉ、Ｍｎ、Ｃｏの質量（μｇ）を表し、Ｎｉ、Ｍｎ、Ｃｏ量（質量％）÷１００×各負極活物質層１枚の質量＝Ｎｉ、Ｍｎ、Ｃｏ量（μｇ／枚）の計算式により表出した。 (Evaluation Example A-13: Confirmation of elution of Ni, Mn, Co)
The lithium ion secondary batteries of Example A-5 and Comparative Example A-3 were used at a voltage range of 3 V to 4.1 V, and charging and discharging were repeated 500 times at a rate of 1C. Each battery was disassembled after 500 charge / discharge cycles, and the negative electrode was taken out. The amounts of Ni, Mn, and Co eluted from the positive electrode into the electrolyte and deposited on the surface of the negative electrode were measured with an ICP (high frequency inductively coupled plasma) emission spectrometer. The measurement results are shown in Table 16. The amounts of Ni, Mn, and Co (% by mass) in Table 16 indicate the mass of Ni, Mn, and Co per 1 g of the negative electrode active material layer, and the amounts of Ni, Mn, and Co (μg / sheet) are Represents the mass (μg) of Ni, Mn, and Co per negative electrode active material layer, Ni, Mn, Co amount (% by mass) ÷ 100 × mass of each negative electrode active material layer = Ni, Mn, Co amount It was expressed by the calculation formula of (μg / sheet).
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000016
　表１６に示すように、実施例Ａ－５の負極は、比較例Ａ－３の負極に比べて、Ｎｉ、Ｍｎ、Ｃｏ量（質量％）及びＮｉ、Ｍｎ、Ｃｏ量（μｇ／枚）とも低かった。表１６に示す結果を表１５に示す結果と合わせると、実施例Ａ－５は、比較例Ａ－３に比べて、正極からの金属溶出が少なく、正極から溶出した金属の負極への析出が少なく、また、容量維持率も高いことがわかった。 As shown in Table 16, the negative electrode of Example A-5 was compared with the negative electrode of Comparative Example A-3 in terms of Ni, Mn, and Co (mass%) and Ni, Mn, and Co (μg / sheet). It was low. Combining the results shown in Table 16 with the results shown in Table 15, Example A-5 had less metal elution from the positive electrode than Comparative Example A-3, and the metal eluted from the positive electrode was deposited on the negative electrode. It was found that there was little capacity maintenance rate.
(評価例Ａ－１４：電極の目付と出力特性)
　この評価例Ａ－１４の評価対象である実施例Ａ－６，比較例Ａ－４は、それぞれ実施例Ａ－１及び比較例Ａ－１の電池と正極の目付が相違する。実施例Ａ－６、比較例Ａ－４については、いずれも正極の目付を５．５ｍｇ／ｃｍ２とし、負極の目付を４ｍｇ／ｃｍ２とした。この電極の目付は、評価例Ａ－１８の（１）～（５）の入力特性及び出力特性の評価で用いた電池の電極の目付の半分、即ち電池容量の半分である。この各電池について以下の３条件で入出力特性を測定した。測定結果を表１７に示す。
＜測定条件＞
・充電状態（ＳＯＣ）３０％、－３０℃、使用電圧範囲３Ｖ―４．２Ｖ、２秒出力
・充電状態（ＳＯＣ）３０％、－１０℃、使用電圧範囲３Ｖ―４．２Ｖ、２秒出力
・充電状態（ＳＯＣ）８０％、２５℃、使用電圧範囲３Ｖ―４．２Ｖ、５秒入力 (Evaluation Example A-14: Electrode weight and output characteristics)
Example A-6 and Comparative Example A-4, which are the evaluation targets of Evaluation Example A-14, differ in the basis weight of the battery of Example A-1 and Comparative Example A-1, respectively. In Example A-6 and Comparative Example A-4, the basis weight of the positive electrode was 5.5 mg / cm 2 and the basis weight of the negative electrode was 4 mg / cm 2 . The basis weight of this electrode is half the basis weight of the battery electrode used in the evaluation of the input characteristics and output characteristics (1) to (5) in Evaluation Example A-18, that is, half the battery capacity. The input / output characteristics of each battery were measured under the following three conditions. Table 17 shows the measurement results.
<Measurement conditions>
-State of charge (SOC) 30%, -30 ° C, operating voltage range 3V-4.2V, 2 seconds output-State of charge (SOC) 30%, -10 ° C, operating voltage range 3V-4.2V, output 2 seconds -State of charge (SOC) 80%, 25 ° C, operating voltage range 3V-4.2V, 5 seconds input
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000017
　表１７に示すように、電極の目付を（１）～（５）の評価に供した電池の半分にしたときにも、実施例Ａ－６の電解液を用いた場合には、比較例Ａ－４の電解液と比べて入出力特性が向上した。 As shown in Table 17, even when the basis weight of the electrodes was half that of the batteries subjected to the evaluations (1) to (5), when the electrolytic solution of Example A-6 was used, Comparative Example A The input / output characteristics were improved compared to the electrolyte solution -4.
（電池Ａ－１）
　電池Ａ－１のリチウムイオン二次電池は、実施例Ａ－１のリチウムイオン二次電池と同様の構成である。 (Battery A-1)
The lithium ion secondary battery of Battery A-1 has the same configuration as the lithium ion secondary battery of Example A-1.
　即ち、電池Ａ－１で用いられる電解液は電解液Ｅ８である。正極の構成は、正極活物質であるＬｉＮｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２（ＮＣＭ２５３）９０質量部、導電助剤であるアセチレンブラック（ＡＢ）８質量部、および結着剤であるポリフッ化ビニリデン（ＰＶｄＦ）２質量部からなる正極活物質層と、正極集電体からなる厚み２０μｍのアルミニウム箔（ＪＩＳ　Ａ１０００番系）とからなる。 That is, the electrolytic solution used in battery A-1 is electrolytic solution E8. The positive electrode is composed of 90 parts by mass of LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM253) as a positive electrode active material, 8 parts by mass of acetylene black (AB) as a conductive auxiliary agent, and a binder. It consists of a positive electrode active material layer composed of 2 parts by mass of certain polyvinylidene fluoride (PVdF) and an aluminum foil (JIS A1000 series) having a thickness of 20 μm composed of a positive electrode current collector.
　電池Ａ－１で用いられる負極は、負極活物質である天然黒鉛９８質量部、ならびに結着剤であるＳＢＲ１質量部およびＣＭＣ１質量部からなる負極活物質層と、負極集電体として厚み２０μｍの銅箔とからなる。 The negative electrode used in Battery A-1 has a negative electrode active material layer composed of 98 parts by mass of natural graphite as a negative electrode active material, 1 part by mass of SBR and 1 part by mass of CMC as a binder, and a negative electrode current collector having a thickness of 20 μm. It consists of copper foil.
　電池Ａ－１で用いられるセパレータは、厚さ２０μｍのセルロース製不織布である。 The separator used in Battery A-1 is a cellulose nonwoven fabric having a thickness of 20 μm.
（電池Ａ－２）
　電池Ａ－２のリチウムイオン二次電池は電解液Ｅ１１を用いたものである。
　電池Ａ－２のリチウムイオン二次電池は、正極活物質と導電助剤と結着剤との混合比、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－１のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＳＢＲ：ＣＭＣ＝９８：１：１とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-2)
The lithium ion secondary battery of the battery A-2 uses the electrolytic solution E11.
The lithium ion secondary battery of battery A-2 is the same as the lithium of battery A-1 except for the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as an ion secondary battery. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: SBR: CMC = 98: 1: 1. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（電池Ａ－３）
　電池Ａ－３のリチウムイオン二次電池は電解液Ｅ１３を用いたものである。電池Ａ－３のリチウムイオン二次電池は、正極活物質と導電助剤と結着剤との混合比、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－１のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＳＢＲ：ＣＭＣ＝９８：１：１とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-3)
The lithium ion secondary battery of the battery A-3 uses the electrolytic solution E13. The lithium ion secondary battery of battery A-3 is the same as the lithium of battery A-1 except for the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as an ion secondary battery. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: SBR: CMC = 98: 1: 1. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（電池Ａ－Ｃ１）
　電池Ａ－Ｃ１のリチウムイオン二次電池は、電解液Ｃ５を用いたものである。電池Ａ－Ｃ１のリチウムイオン二次電池は、電解液の種類、正極活物質と導電助剤と結着剤との混合比、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－１のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＳＢＲ：ＣＭＣ＝９８：１：１とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-C1)
The lithium ion secondary battery of Battery A-C1 uses an electrolytic solution C5. The battery A-C1 lithium ion secondary battery is a battery other than the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery A-1. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: SBR: CMC = 98: 1: 1. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（評価例Ａ－１５：電池の内部抵抗）
　電池Ａ－１～電池Ａ－３および電池Ａ－Ｃ１のリチウムイオン二次電池を準備し、電池の内部抵抗を評価した。 (Evaluation Example A-15: Internal resistance of battery)
Lithium ion secondary batteries of Battery A-1 to Battery A-3 and Battery A-C1 were prepared, and the internal resistance of the batteries was evaluated.
　電池Ａ－１～電池Ａ－３および電池Ａ－Ｃ１の各リチウムイオン二次電池について、室温、３．０Ｖ～４．１Ｖ(ｖｓ．Ｌｉ基準)の範囲でＣＣ充放電（つまり定電流充放電）を繰り返した。そして、初回充放電後の交流インピーダンス、および、１００サイクル経過後の交流インピーダンスを測定した。得られた複素インピーダンス平面プロットを基に、電解液、負極および正極の反応抵抗を各々解析した。図３９に示すように、複素インピーダンス平面プロットには、二つの円弧がみられた。図中左側（つまり複素インピーダンスの実部が小さい側）の円弧を第１円弧と呼ぶ。図中右側の円弧を第２円弧と呼ぶ。第１円弧の大きさを基に負極の反応抵抗を解析し、第２円弧の大きさを基に正極の反応抵抗を解析した。第１円弧に連続する図３９中最左側のプロットを基に電解液の抵抗を解析した。解析結果を表１８および表１９に示す。なお、表１８は、初回充放電後の電解液の抵抗（所謂溶液抵抗）、負極の反応抵抗、正極の反応抵抗、及び拡散抵抗を示し、表１９は１００サイクル経過後の各抵抗を示す。 For each of the lithium ion secondary batteries of battery A-1 to battery A-3 and battery A-C1, CC charge / discharge (that is, constant current charge / discharge) is performed at room temperature and in the range of 3.0 V to 4.1 V (vs. Li standard). ) Was repeated. Then, the AC impedance after the first charge / discharge and the AC impedance after 100 cycles were measured. Based on the obtained complex impedance plane plot, the reaction resistances of the electrolytic solution, the negative electrode, and the positive electrode were each analyzed. As shown in FIG. 39, two circular arcs were seen in the complex impedance plane plot. The arc on the left side of the figure (that is, the side where the real part of the complex impedance is small) is called the first arc. The arc on the right side in the figure is called the second arc. The reaction resistance of the negative electrode was analyzed based on the size of the first arc, and the reaction resistance of the positive electrode was analyzed based on the size of the second arc. The resistance of the electrolytic solution was analyzed based on the leftmost plot in FIG. 39 continuous with the first arc. The analysis results are shown in Table 18 and Table 19. Table 18 shows the resistance (so-called solution resistance) of the electrolytic solution after the first charge / discharge, the reaction resistance of the negative electrode, the reaction resistance of the positive electrode, and the diffusion resistance. Table 19 shows the resistance after 100 cycles.
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
　表１８および表１９に示すように、各リチウムイオン二次電池において、１００サイクル経過後の負極反応抵抗および正極反応抵抗は、初回充放電後の各抵抗に比べて低下する傾向にある。そして、表１９に示す１００サイクル経過後では、電池Ａ－１～電池Ａ－３のリチウムイオン二次電池の負極反応抵抗および正極反応抵抗は、電池Ａ－Ｃ１のリチウムイオン二次電池の負極反応抵抗および正極反応抵抗に比べて低い。 As shown in Table 18 and Table 19, in each lithium ion secondary battery, the negative electrode reaction resistance and the positive electrode reaction resistance after 100 cycles elapse tend to be lower than the respective resistances after the first charge / discharge. After 100 cycles shown in Table 19, the negative electrode reaction resistance and the positive electrode reaction resistance of the lithium ion secondary batteries of the batteries A-1 to A-3 were the negative electrode reaction of the lithium ion secondary battery of the battery A-C1. Low compared to resistance and positive electrode reaction resistance.
　上述したように、電池Ａ－１，電池Ａ－２のリチウムイオン二次電池は本発明の電解液を用いたものであり、負極および正極の表面には本発明の電解液に由来するＳ，Ｏ含有皮膜が形成されている。これに対して、本発明の電解液を用いていない電池Ａ－Ｃ１のリチウムイオン二次電池においては、負極および正極の表面には当該Ｓ，Ｏ含有皮膜は形成されていない。そして、電池Ａ－１、電池Ａ－２の負極反応抵抗および正極反応抵抗は電池Ａ－Ｃ１のリチウムイオン二次電池よりも低い。このことから、電池Ａ－１～電池Ａ－３においては、本発明の電解液に由来するＳ，Ｏ含有皮膜の存在により負極反応抵抗および正極反応抵抗が低減したと推察される。 As described above, the lithium ion secondary batteries of the battery A-1 and the battery A-2 are those using the electrolytic solution of the present invention, and the surfaces of the negative electrode and the positive electrode are S, derived from the electrolytic solution of the present invention. An O-containing film is formed. On the other hand, in the lithium ion secondary battery of the battery A-C1 that does not use the electrolytic solution of the present invention, the S, O-containing film is not formed on the surfaces of the negative electrode and the positive electrode. The negative electrode reaction resistance and the positive electrode reaction resistance of the batteries A-1 and A-2 are lower than those of the lithium ion secondary battery of the battery A-C1. From this, it is presumed that in the batteries A-1 to A-3, the negative electrode reaction resistance and the positive electrode reaction resistance were reduced due to the presence of the S, O-containing film derived from the electrolytic solution of the present invention.
　なお、電池Ａ－２および電池Ａ－Ｃ１のリチウムイオン二次電池における電解液の溶液抵抗はほぼ同じであり、電池Ａ－１のリチウムイオン二次電池における電解液の溶液抵抗は、電池Ａ－２および電池Ａ－Ｃ１に比べて高い。また、各リチウムイオン二次電池における各電解液の溶液抵抗は初回充放電後も１００サイクル経過後も同じである。このため、各電解液の耐久劣化は生じていないと考えられ、上記した電池Ａ－Ｃ１および電池Ａ－１～電池Ａ－３において生じた負極反応抵抗および正極反応抵抗の差は、電解液の耐久劣化に関係するものでなく電極自体に生じているものであると考えられる。 Note that the solution resistance of the electrolyte solution in the lithium ion secondary batteries of the battery A-2 and the battery A-C1 is substantially the same, and the solution resistance of the electrolyte solution in the lithium ion secondary battery of the battery A-1 is 2 and higher than batteries A-C1. Moreover, the solution resistance of each electrolyte solution in each lithium ion secondary battery is the same after the first charge / discharge and after 100 cycles. For this reason, it is considered that each electrolyte solution does not deteriorate in durability, and the difference between the negative electrode reaction resistance and the positive electrode reaction resistance generated in the batteries A-C1 and batteries A-1 to A-3 is the difference between the electrolyte solutions. It is thought that it is not related to durability deterioration but is generated in the electrode itself.
　リチウムイオン二次電池の内部抵抗は、電解液の溶液抵抗、負極の反応抵抗および正極の反応抵抗から総合的に判断できる。表１８および表１９の結果を基にすると、リチウムイオン二次電池の内部抵抗増大を抑制する観点からは、電池Ａ－１のリチウムイオン二次電池が最も耐久性に優れ、次いで電池Ａ－２のリチウムイオン二次電池が耐久性に優れていると言える。 The internal resistance of the lithium ion secondary battery can be comprehensively determined from the solution resistance of the electrolytic solution, the reaction resistance of the negative electrode, and the reaction resistance of the positive electrode. Based on the results of Table 18 and Table 19, from the viewpoint of suppressing the increase in internal resistance of the lithium ion secondary battery, the lithium ion secondary battery of battery A-1 has the most excellent durability, and then battery A-2 It can be said that the lithium ion secondary battery is excellent in durability.
（評価例Ａ－１６：電池のサイクル耐久性）
　電池Ａ－１～電池Ａ－３、電池Ａ－Ｃ１の各リチウムイオン二次電池について、室温、３．０Ｖ～４．１Ｖ(ｖｓ．Ｌｉ基準)の範囲でＣＣ充放電を繰り返し、初回充放電時の放電容量、１００サイクル時の放電容量、および５００サイクル時の放電容量を測定した。そして、初回充放電時の各リチウムイオン二次電池の容量を１００％とし、１００サイクル時および５００サイクル時の各リチウムイオン二次電池の容量維持率（％）を算出した。結果を表２０に示す。 (Evaluation Example A-16: Battery cycle durability)
For each of the lithium ion secondary batteries of battery A-1 to battery A-3 and battery A-C1, CC charge / discharge was repeated at room temperature in the range of 3.0 V to 4.1 V (vs. Li standard), and the initial charge / discharge Discharge capacity at 100 cycles, discharge capacity at 100 cycles, and discharge capacity at 500 cycles were measured. And the capacity | capacitance maintenance factor (%) of each lithium ion secondary battery at the time of 100 cycles and 500 cycles was computed by making the capacity | capacitance of each lithium ion secondary battery at the time of initial charge / discharge into 100%. The results are shown in Table 20.
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000020
　表２０に示すように、電池Ａ－１，電池Ａ－２のリチウムイオン二次電池は、ＳＥＩの材料となるＥＣを含まないにも拘わらず、ＥＣを含む電池Ａ－Ｃ１のリチウムイオン二次電池と同等の容量維持率を示した。これは、電池Ａ－１，電池Ａ－２のリチウムイオン二次電池における正極および負極には、本発明の電解液に由来するＳ，Ｏ含有皮膜が存在するためだと考えられる。そして、電池Ａ－２のリチウムイオン二次電池については、特に５００サイクル経過時にも極めて高い容量維持率を示し、特に耐久性に優れていた。この結果から、有機溶媒としてＤＭＣを選択する場合には、ＡＮを選択する場合に比べて、より耐久性が向上するといえる。 As shown in Table 20, the lithium ion secondary batteries of the battery A-1 and the battery A-2 do not contain the EC that is the material of the SEI, but the lithium ion secondary battery of the battery A-C1 containing the EC. The capacity retention rate was the same as the battery. This is considered to be because the S and O-containing films derived from the electrolytic solution of the present invention exist on the positive electrode and the negative electrode in the lithium ion secondary batteries of the batteries A-1 and A-2. The lithium ion secondary battery of battery A-2 exhibited a very high capacity retention rate even after 500 cycles had elapsed, and was particularly excellent in durability. From this result, it can be said that when DMC is selected as the organic solvent, the durability is further improved as compared with the case where AN is selected.
（電池Ａ－４）
　電解液Ｅ８を用いたハーフセルを以下のとおり製造した。 (Battery A-4)
A half cell using the electrolytic solution E8 was produced as follows.
　活物質である平均粒径１０μｍの黒鉛９０質量部、及び結着剤であるポリフッ化ビニリデン１０質量部を混合した。この混合物を適量のＮ－メチル－２－ピロリドンに分散させて、スラリーを作製した。集電体として厚み２０μｍの銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を乾燥してＮ－メチル－２－ピロリドンを除去し、その後、銅箔をプレスし、接合物を得た。得られた接合物を真空乾燥機で１２０℃、６時間加熱乾燥して、活物質層が形成された銅箔を得た。これを作用極とした。なお、銅箔１ｃｍ２あたりの活物質の質量は１．４８ｍｇであった。また、プレス前の黒鉛及びポリフッ化ビニリデンの密度は０．６８ｇ／ｃｍ３であり、プレス後の活物質層の密度は１．０２５ｇ／ｃｍ３であった。 90 parts by mass of graphite having an average particle diameter of 10 μm as an active material and 10 parts by mass of polyvinylidene fluoride as a binder were mixed. This mixture was dispersed in an appropriate amount of N-methyl-2-pyrrolidone to prepare a slurry. A copper foil having a thickness of 20 μm was prepared as a current collector. The slurry was applied in a film form on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried to remove N-methyl-2-pyrrolidone, and then the copper foil was pressed to obtain a bonded product. The obtained joined product was heat-dried at 120 ° C. for 6 hours with a vacuum dryer to obtain a copper foil on which an active material layer was formed. This was the working electrode. In addition, the mass of the active material per 1 cm 2 of copper foil was 1.48 mg. Further, the density of graphite and polyvinylidene fluoride before pressing was 0.68 g / cm 3 , and the density of the active material layer after pressing was 1.025 g / cm 3 .
　対極は金属Ｌｉとした。 The counter electrode was metal Li.
　作用極、対極、及び電解液Ｅ８を、径１３．８２ｍｍの電池ケース（宝泉株式会社製　ＣＲ２０３２型コインセルケース）に収容しハーフセルを構成した。これを電池Ａ－４のハーフセルとした。 The working electrode, the counter electrode, and the electrolytic solution E8 were accommodated in a battery case with a diameter of 13.82 mm (CR2032 type coin cell case manufactured by Hosen Co., Ltd.) to form a half cell. This was designated as the half cell of Battery A-4.
（電池Ａ－５）
　電解液Ｅ１１を用いた以外は、電池Ａ－４と同様の方法で、電池Ａ－５のハーフセルを製造した。 (Battery A-5)
A half cell of Battery A-5 was produced in the same manner as Battery A-4, except that the electrolytic solution E11 was used.
（電池Ａ－６）
　電解液Ｅ１６を用いた以外は、電池Ａ－４と同様の方法で、電池Ａ－６のハーフセルを製造した。 (Battery A-6)
A half cell of Battery A-6 was produced in the same manner as Battery A-4, except that the electrolytic solution E16 was used.
（電池Ａ－７）
　電解液Ｅ１９の電解液を用いた以外は、電池Ａ－４と同様の方法で、電池Ａ－７のハーフセルを製造した。 (Battery A-7)
A half cell of Battery A-7 was produced in the same manner as Battery A-4, except that the electrolytic solution E19 was used.
（電池Ａ－Ｃ２）
　電解液Ｃ５を用いた以外は、電池Ａ－４と同様の方法で、電池Ａ－Ｃ２のハーフセルを製造した。 (Battery A-C2)
A half cell of Battery A-C2 was produced in the same manner as Battery A-4, except that Electrolyte C5 was used.
（評価例Ａ－１７：レート特性）
　電池Ａ－４～電池Ａ－７、電池Ａ－Ｃ２のハーフセルのレート特性を以下の方法で試験した。
ハーフセルに対し、０．１Ｃ、０．２Ｃ、０．５Ｃ、１Ｃ、２Ｃレート（１Ｃとは一定電流において１時間で電池を完全充電または放電させるために要する電流値を意味する。）で充電を行った後に放電を行い、それぞれの速度における作用極の容量（放電容量）を測定した。なお、ここでの記述は、対極を負極、作用極を正極とみなしている。０．１Ｃレートでの作用極の容量に対する他のレートにおける容量の割合（レート特性）を算出した。結果を表２１に示す。 (Evaluation Example A-17: Rate characteristics)
The rate characteristics of the half cells of Battery A-4 to Battery A-7 and Battery A-C2 were tested by the following method.
The half cell is charged at a rate of 0.1 C, 0.2 C, 0.5 C, 1 C, and 2 C (1 C means a current value required to fully charge or discharge the battery in one hour at a constant current). After the discharge, discharge was performed, and the capacity (discharge capacity) of the working electrode at each speed was measured. In this description, the counter electrode is regarded as a negative electrode and the working electrode is regarded as a positive electrode. The ratio (rate characteristic) of the capacity at other rates to the capacity of the working electrode at the 0.1 C rate was calculated. The results are shown in Table 21.
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000021
　電池Ａ－４～電池Ａ－７のハーフセルは０．２Ｃ、０．５Ｃ、１Ｃのレートにおいて、さらに、電池Ａ－４、電池Ａ－５は２Ｃのレートにおいても電池Ａ－Ｃ１のハーフセルと比較して、容量低下が抑制されており、優れたレート特性を示すことが裏付けられた。 Battery A-4 to Battery A-7 half-cells at 0.2C, 0.5C and 1C rates, and Battery A-4 and Battery A-5 are also compared to Battery A-C1 half-cells at 2C rates. Thus, it was confirmed that the capacity decrease was suppressed and an excellent rate characteristic was exhibited.
（評価例Ａ－１８：容量維持率）
　電池Ａ－４～電池Ａ－７、電池Ａ－Ｃ２のハーフセルの容量維持率を以下の方法で試験した。 (Evaluation Example A-18: Capacity maintenance rate)
The capacity retention rates of the half cells of Battery A-4 to Battery A-7 and Battery A-C2 were tested by the following method.
各ハーフセルに対し、２５℃、電圧２．０ＶまでＣＣ充電（定電流充電）し、電圧０．０１ＶまでＣＣ放電(定電流放電)を行う２．０Ｖ－０．０１Ｖの充放電サイクルを、充放電レート０．１Ｃで３サイクル行い、その後、０．２Ｃ、０．５Ｃ、１Ｃ、２Ｃ、５Ｃ、１０Ｃの順で各充放電レートにつき３サイクルずつ充放電を行い、最後に０．１Ｃで３サイクル充放電を行った。各ハーフセルの容量維持率（％）は以下の式で求めた。 Each half cell is charged with a 2.0V-0.01V charge / discharge cycle in which CC charging (constant current charging) is performed to 25 ° C. and voltage 2.0V, and CC discharging (constant current discharging) is performed to voltage 0.01V. Perform 3 cycles at a discharge rate of 0.1C, then charge and discharge 3 cycles at each charge / discharge rate in the order of 0.2C, 0.5C, 1C, 2C, 5C, 10C, and finally 3 at 0.1C. Cycle charge / discharge was performed. The capacity retention rate (%) of each half cell was determined by the following formula.
　容量維持率（％）＝Ｂ／Ａ×１００
　Ａ：最初の０．１Ｃ充放電サイクルにおける２回目の作用極の放電容量
　Ｂ：最後の０．１Ｃの充放電サイクルにおける２回目の作用極の放電容量
　結果を表２２に示す。なお、ここでの記述は、対極を負極、作用極を正極とみなしている。 Capacity maintenance rate (%) = B / A × 100
A: Discharge capacity of the second working electrode in the first 0.1 C charge / discharge cycle B: Discharge capacity of the second working electrode in the last 0.1 C charge / discharge cycle Table 22 shows the results. In this description, the counter electrode is regarded as a negative electrode and the working electrode is regarded as a positive electrode.
Figure JPOXMLDOC01-appb-T000022
 　いずれのハーフセルも、良好に充放電反応を行い、好適な容量維持率を示した。特に、電池Ａ－５，電池Ａ－６、電池Ａ－７のハーフセルの容量維持率は著しく優れていた。
Figure JPOXMLDOC01-appb-T000022
 All of the half cells performed a charge / discharge reaction satisfactorily and exhibited a suitable capacity retention rate. In particular, the capacity retention rates of the half cells of battery A-5, battery A-6, and battery A-7 were remarkably excellent.
（電池Ａ－８）
　電解液Ｅ８を用いた電池Ａ－８のリチウムイオン二次電池は、上記の電池Ａ－１のリチウムイオン二次電池と同様である。正極活物質層中の成分配合比については、ＮＣＭ５２３：ＡＢ：ＰＶＤＦ＝９４：３：３であり、セパレータとしては、実験用濾紙（東洋濾紙株式会社、セルロース製、厚み２６０μｍ）を用いた。電池Ａ－８のリチウムイオン二次電池における電解液Ｅ８は、（ＦＳＯ２）２ＮＬｉの濃度が４．５ｍｏｌ／Ｌである。電解液Ｅ８においては、（ＦＳＯ２）２ＮＬｉ１分子に対しアセトニトリル２．４分子が含まれている。 (Battery A-8)
The lithium ion secondary battery of the battery A-8 using the electrolytic solution E8 is the same as the lithium ion secondary battery of the battery A-1. About the component mixture ratio in a positive electrode active material layer, it is NCM523: AB: PVDF = 94: 3: 3, and the filter paper for experiment (Toyo Filter Paper Co., Ltd., cellulose, thickness 260 micrometers) was used as a separator. The electrolyte solution E8 in the lithium ion secondary battery of the battery A-8 has a (FSO 2 ) 2 NLi concentration of 4.5 mol / L. In the electrolytic solution E8, 2.4 molecules of acetonitrile are contained with respect to (FSO 2 ) 2 NLi1 molecules.
（電池Ａ－９）
　電池Ａ－９のリチウムイオン二次電池は、電解液として電解液Ｅ４を用いたこと以外は電池Ａ－８のリチウムイオン二次電池と同じものである。電池Ａ－９のリチウムイオン二次電池における電解液は、溶媒としてのアセトニトリルに、支持塩としての（ＳＯ２ＣＦ３）２ＮＬｉ（ＬｉＴＦＳＡ）を溶解してなる。電解液１リットルに含まれるリチウム塩の濃度は、４．２ｍｏｌ／Ｌである。電解液は、リチウム塩１分子に対して、２分子のアセトニトリルを含む。 (Battery A-9)
The lithium ion secondary battery of Battery A-9 is the same as the lithium ion secondary battery of Battery A-8, except that electrolytic solution E4 was used as the electrolytic solution. The electrolyte in the lithium ion secondary battery of Battery A-9 is obtained by dissolving (SO 2 CF 3 ) 2 NLi (LiTFSA) as a supporting salt in acetonitrile as a solvent. The concentration of the lithium salt contained in 1 liter of the electrolytic solution is 4.2 mol / L. The electrolytic solution contains two molecules of acetonitrile with respect to one molecule of the lithium salt.
（電池Ａ－１０）
　電池Ａ－１０のリチウムイオン二次電池は、電解液として電解液Ｅ１１を用いたこと以外は電池Ａ－８のリチウムイオン二次電池と同じものである。電池Ａ－１０のリチウムイオン二次電池における電解液は、溶媒としてのＤＭＣに、支持塩としてのＬｉＦＳＡを溶解してなる。電解液１リットルに含まれるリチウム塩の濃度は、３．９ｍｏｌ／Ｌである。電解液は、リチウム塩１分子に対して、２分子のＤＭＣを含む。 (Battery A-10)
The lithium ion secondary battery of the battery A-10 is the same as the lithium ion secondary battery of the battery A-8 except that the electrolytic solution E11 is used as the electrolytic solution. The electrolyte in the lithium ion secondary battery of Battery A-10 is obtained by dissolving LiFSA as a supporting salt in DMC as a solvent. The concentration of the lithium salt contained in 1 liter of the electrolytic solution is 3.9 mol / L. The electrolytic solution contains two molecules of DMC with respect to one molecule of the lithium salt.
（電池Ａ－１１）
　電池Ａ－１１のリチウムイオン二次電池は電解液Ｅ１１を用いたものである。電池Ａ－１１のリチウムイオン二次電池は、電解液の種類、正極活物質と導電助剤と結着剤との混合比、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－８のリチウムイオン二次電池と同じものである。正極については、正極活物質としてＮＣＭ５２３を用い、正極用の導電助剤としてＡＢを用い、結着剤としてはＰＶｄＦを用いた。これは電池Ａ－８と同様である。これらの配合比は、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２であった。正極における活物質層の目付量は５．５ｍｇ／ｃｍ２であり、密度は２．５ｇ／ｃｍ３であった。これは以下の電池Ａ－１２～電池Ａ－１５および電池Ａ－Ｃ３～電池Ａ－Ｃ５についても同様である。 (Battery A-11)
The lithium ion secondary battery of Battery A-11 uses the electrolytic solution E11. The lithium ion secondary battery of battery A-11 is a battery other than the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery of A-8. For the positive electrode, NCM523 was used as the positive electrode active material, AB was used as the conductive additive for the positive electrode, and PVdF was used as the binder. This is the same as battery A-8. These compounding ratios were NCM523: AB: PVdF = 90: 8: 2. The basis weight of the active material layer in the positive electrode was 5.5 mg / cm 2 and the density was 2.5 g / cm 3 . The same applies to the following batteries A-12 to A-15 and batteries A-C3 to A-C5.
　負極については、負極活物質として天然黒鉛を用い、負極用の結着材としてＳＢＲおよびＣＭＣを用いた。これもまた電池Ａ－８と同様である。これらの配合比は、天然黒鉛：ＳＢＲ：ＣＭＣ＝９８：１：１であった。負極における活物質層の目付量は３．８ｍｇ／ｃｍ２であり、密度は１．１ｇ／ｃｍ３であった。これは以下の電池Ａ－１２～電池Ａ－１５および電池Ａ－Ｃ３～電池Ａ－Ｃ５についても同様である。 For the negative electrode, natural graphite was used as the negative electrode active material, and SBR and CMC were used as the binder for the negative electrode. This is also the same as battery A-8. These compounding ratios were natural graphite: SBR: CMC = 98: 1: 1. The basis weight of the active material layer in the negative electrode was 3.8 mg / cm 2 , and the density was 1.1 g / cm 3 . The same applies to the following batteries A-12 to A-15 and batteries A-C3 to A-C5.
　セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 As the separator, a cellulose nonwoven fabric having a thickness of 20 μm was used.
　電池Ａ－１１のリチウムイオン二次電池における電解液は、溶媒としてのＤＭＣに、支持塩としてのＬｉＦＳＡを溶解してなる。電解液１リットルに含まれるリチウム塩の濃度は、３．９ｍｏｌ／Ｌである。電解液は、リチウム塩１分子に対して、２分子のＤＭＣを含む。 The electrolyte in the lithium ion secondary battery of battery A-11 is obtained by dissolving LiFSA as a supporting salt in DMC as a solvent. The concentration of the lithium salt contained in 1 liter of the electrolytic solution is 3.9 mol / L. The electrolytic solution contains two molecules of DMC with respect to one molecule of the lithium salt.
（電池Ａ－１２）
　電池Ａ－１２のリチウムイオン二次電池は電解液Ｅ８を用いたものである。電池Ａ－１２のリチウムイオン二次電池は、正極活物質と導電助剤と結着剤との混合比、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－８のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＳＢＲ：ＣＭＣ＝９８：１：１とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-12)
The lithium ion secondary battery of Battery A-12 uses the electrolytic solution E8. The lithium ion secondary battery of battery A-12 is composed of the lithium active battery of battery A-8 except for the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as an ion secondary battery. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: SBR: CMC = 98: 1: 1. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（電池Ａ－１３）
　電池Ａ－１３のリチウムイオン二次電池は電解液Ｅ１１を用いたものである。電池Ａ－１３のリチウムイオン二次電池は、電解液の種類、正極活物質と導電助剤と結着剤との混合比、負極用の結着材の種類、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－８のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、負極活物質として天然黒鉛を用い、負極用の結着材としてポリアクリル酸（ＰＡＡ）を用いた。これらの配合比は、天然黒鉛：ＰＡＡ＝９０：１０であった。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-13)
The lithium ion secondary battery of the battery A-13 uses the electrolytic solution E11. The lithium ion secondary battery of Battery A-13 includes the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive, and the binder, the type of binder for the negative electrode, the negative electrode active material and the binder, Except for the mixing ratio and the separator, the lithium ion secondary battery of Battery A-8 was the same. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. For the negative electrode, natural graphite was used as the negative electrode active material, and polyacrylic acid (PAA) was used as the binder for the negative electrode. These compounding ratios were natural graphite: PAA = 90: 10. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（電池Ａ－１４）
　電池Ａ－１４のリチウムイオン二次電池は電解液Ｅ８を用いたものである。電池Ａ－１４のリチウムイオン二次電池は、正極活物質と導電助剤と結着剤との混合比、負極用の結着材の種類、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－８のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＰＡＡ＝９０：１０とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-14)
The lithium ion secondary battery of Battery A-14 uses the electrolytic solution E8. The lithium ion secondary battery of Battery A-14 has a mixing ratio of the positive electrode active material, the conductive additive and the binder, the type of binder for the negative electrode, the mixing ratio of the negative electrode active material and the binder, and Except for the separator, it is the same as the lithium ion secondary battery of Battery A-8. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: PAA = 90: 10. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（電池Ａ－１５）
　電池Ａ－１５のリチウムイオン二次電池は電解液Ｅ１３を用いたものである。電池Ａ－１５のリチウムイオン二次電池は、正極活物質と導電助剤との混合比、負極用の結着材の種類、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－１のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＳＢＲ：ＣＭＣ＝９８：１：１とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-15)
The lithium ion secondary battery of Battery A-15 uses the electrolytic solution E13. The lithium ion secondary battery of Battery A-15 is a battery other than the mixing ratio of the positive electrode active material and the conductive additive, the type of binder for the negative electrode, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery A-1. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: SBR: CMC = 98: 1: 1. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（電池Ａ－Ｃ３）
　電池Ａ－Ｃ３のリチウムイオン二次電池は、電解液Ｃ５を用いた以外は、電池Ａ－１と同様である。 (Battery A-C3)
The lithium ion secondary battery of Battery A-C3 is the same as Battery A-1, except that electrolyte C5 is used.
（電池Ａ－Ｃ４）
　電池Ａ－Ｃ４のリチウムイオン二次電池は、電解液Ｃ５を用いたものである。電池Ａ－Ｃ４のリチウムイオン二次電池は、電解液の種類、正極活物質と導電助剤と結着剤との混合比、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－１のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＳＢＲ：ＣＭＣ＝９８：１：１とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。 (Battery A-C4)
The lithium ion secondary battery of batteries A to C4 uses the electrolytic solution C5. Battery A-C4 lithium ion secondary battery is a battery other than the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive and the binder, the mixing ratio of the negative electrode active material and the binder, and the separator. It is the same as the lithium ion secondary battery A-1. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: SBR: CMC = 98: 1: 1. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
（電池Ａ－Ｃ５）
　電池Ａ－Ｃ５のリチウムイオン二次電池は電解液Ｃ５を用いたものである。電池Ａ－Ｃ５のリチウムイオン二次電池は、電解液の種類、正極活物質と導電助剤と結着剤との混合比、負極用の結着材の種類、負極活物質と結着剤との混合比、およびセパレータ以外は電池Ａ－１のリチウムイオン二次電池と同じものである。正極については、ＮＣＭ５２３：ＡＢ：ＰＶｄＦ＝９０：８：２とした。負極については、天然黒鉛：ＰＡＡ＝９０：１０とした。セパレータとしては厚さ２０μｍのセルロース製不織布を用いた。
　各電池の電池構成を表２３に示す。 (Battery A-C5)
The lithium ion secondary battery of batteries A to C5 uses an electrolytic solution C5. Lithium ion secondary batteries of batteries A to C5 include the type of electrolyte, the mixing ratio of the positive electrode active material, the conductive additive, and the binder, the type of binder for the negative electrode, the negative electrode active material and the binder, Except for the mixing ratio and the separator, the lithium-ion secondary battery of Battery A-1 is the same. About the positive electrode, it was set as NCM523: AB: PVdF = 90: 8: 2. The negative electrode was natural graphite: PAA = 90: 10. A cellulose nonwoven fabric with a thickness of 20 μm was used as the separator.
Table 23 shows the battery configuration of each battery.
Figure JPOXMLDOC01-appb-T000023
Figure JPOXMLDOC01-appb-T000023
（評価例Ａ－１９：Ｓ，Ｏ含有皮膜の分析）
　以下、必要に応じて、電池Ａ－８～Ａ－１５のリチウムイオン二次電池における負極の表面に形成されているＳ，Ｏ含有皮膜を各電池の負極Ｓ，Ｏ含有皮膜と略し、電池Ａ－Ｃ３～Ａ－Ｃ５のリチウムイオン二次電池における負極の表面に形成されている皮膜を各電池の負極皮膜と略する。 (Evaluation Example A-19: Analysis of coating containing S and O)
Hereinafter, the S, O-containing film formed on the surface of the negative electrode in each of the lithium ion secondary batteries of batteries A-8 to A-15 is abbreviated as the negative electrode S, O-containing film of each battery. The film formed on the surface of the negative electrode in the -C3 to A-C5 lithium ion secondary batteries is abbreviated as the negative electrode film of each battery.
　また、必要に応じて、各電池Ａ－８～Ａ－１５のリチウムイオン二次電池における正極の表面に形成されている皮膜を各電池Ａ－８～Ａ－１５の正極Ｓ，Ｏ含有皮膜と略し、各電池Ａ－Ｃ３～Ａ－Ｃ５のリチウムイオン二次電池における正極の表面に形成されている皮膜を各電池Ａ－Ｃ３～Ａ－Ｃ５の正極皮膜と略する。 Further, if necessary, the film formed on the surface of the positive electrode in each of the lithium ion secondary batteries of the batteries A-8 to A-15 is replaced with the positive electrode S, O-containing film of the batteries A-8 to A-15. For brevity, the film formed on the surface of the positive electrode in the lithium ion secondary battery of each of the batteries AC3 to AC5 is abbreviated as the positive electrode film of each of the batteries AC3 to AC5.
（負極Ｓ，Ｏ含有皮膜および負極皮膜の分析）
　電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３のリチウムイオン二次電池について、１００サイクル充放電を繰り返した後に、電圧３．０Ｖの放電状態でＸ線光電子分光分析（Ｘ－ｒａｙ　Ｐｈｏｔｏｅｌｅｃｔｒｏｎ　Ｓｐｅｃｔｒｏｓｃｏｐｙ、ＸＰＳ）によりＳ，Ｏ含有皮膜または皮膜表面の分析を行った。前処理としては以下の処理を行った。先ず、リチウムイオン二次電池を解体して負極を取出し、この負極を洗浄および乾燥して、分析対象となる負極を得た。洗浄は、ＤＭＣ（ジメチルカーボネート）を用いて３回行った。また、セルの解体から分析対象としての負極を分析装置に搬送するまでの全ての工程を、Ａｒガス雰囲気下で、負極を大気に触れさせることなく行った。以下の前処理を電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３の各リチウムイオン二次電池ついて行い、得られた負極検体をＸＰＳ分析した。装置としては、アルバックファイ社　ＰＨＩ５０００　ＶｅｒｓａＰｒｏｂｅＩＩを用いた。Ｘ線源は単色ＡｌＫα線（１５ｋＶ、１０ｍＡ）であった。ＸＰＳにより測定された電池Ａ－８、電池Ａ－９の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ３の負極皮膜の分析結果を図４０～図４４に示す。具体的には、図４０は炭素元素についての分析結果であり、図４１はフッ素元素についての分析結果であり、図４２は窒素元素についての分析結果であり、図４３は酸素元素についての分析結果であり、図４４は硫黄元素についての分析結果である。 (Analysis of negative electrode S, O-containing film and negative electrode film)
For the lithium ion secondary batteries of Battery A-8, Battery A-9, and Battery A-C3, after 100 cycles of charge / discharge, X-ray Photoelectron Spectroscopy (X-ray Photoelectron Spectroscopy) was performed in a discharge state of 3.0 V. , XPS) to analyze the S, O-containing film or the film surface. The following processing was performed as preprocessing. First, the lithium ion secondary battery was disassembled, the negative electrode was taken out, the negative electrode was washed and dried, and the negative electrode to be analyzed was obtained. Washing was performed 3 times using DMC (dimethyl carbonate). In addition, all steps from disassembling the cell to conveying the negative electrode as the analysis target to the analyzer were performed in an Ar gas atmosphere without exposing the negative electrode to the atmosphere. The following pretreatment was performed on each of the lithium ion secondary batteries of Battery A-8, Battery A-9, and Battery A-C3, and the obtained negative electrode specimen was analyzed by XPS. As the apparatus, ULVAC-PHI PHI5000 VersaProbeII was used. The X-ray source was monochromatic AlKα radiation (15 kV, 10 mA). The analysis results of the negative electrode S, O-containing film of Battery A-8, Battery A-9, and the negative electrode film of Battery A-C3 measured by XPS are shown in FIGS. Specifically, FIG. 40 shows the analysis result for carbon element, FIG. 41 shows the analysis result for fluorine element, FIG. 42 shows the analysis result for nitrogen element, and FIG. 43 shows the analysis result for oxygen element. FIG. 44 shows the analysis results for the elemental sulfur.
　電池Ａ－８のリチウムイオン二次電池における電解液、および電池Ａ－９のリチウムイオン二次電池における電解液は、塩に硫黄元素（Ｓ）、酸素元素および窒素元素（Ｎ）を含む。これに対して電池Ａ－Ｃ３のリチウムイオン二次電池における電解液は、塩にこれらを含まない。さらに、電池Ａ－８、電池Ａ－９および電池Ａ－Ｃ３のリチウムイオン二次電池における電解液は、いずれも、塩にフッ素元素（Ｆ）炭素元素（Ｃ）および酸素元素（Ｏ）を含む。 The electrolyte in the lithium ion secondary battery of Battery A-8 and the electrolyte in the lithium ion secondary battery of Battery A-9 contain sulfur element (S), oxygen element and nitrogen element (N) in the salt. In contrast, the electrolyte in the lithium ion secondary battery of batteries A to C3 does not contain these in the salt. Furthermore, the electrolytes in the lithium ion secondary batteries of Battery A-8, Battery A-9, and Battery A-C3 all contain fluorine element (F), carbon element (C), and oxygen element (O) in the salt. .
　図４０～図４４に示すように、電池Ａ－８の負極Ｓ，Ｏ含有皮膜および電池Ａ－９の負極Ｓ，Ｏ含有皮膜を分析した結果、Ｓの存在を示すピーク（図４４）およびＮの存在を示すピーク（図４２）が観察された。つまり、電池Ａ－８の負極Ｓ，Ｏ含有皮膜および電池Ａ－９の負極Ｓ，Ｏ含有皮膜はＳおよびＮを含んでいた。しかし、電池Ａ－Ｃ３の負極皮膜の分析結果においてはこれらのピークは確認されなかった。つまり、電池Ａ－Ｃ３の負極皮膜はＳおよびＮの何れについても、検出限界以上の量を含んでいなかった。なお、Ｆ、Ｃ、およびＯの存在を示すピークは、電池Ａ－８、電池Ａ－９の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ３の負極皮膜の分析結果全てにおいて観察された。つまり、電池Ａ－８、電池Ａ－９の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ３の負極皮膜は何れもＦ、Ｃ、およびＯを含んでいた。 As shown in FIGS. 40 to 44, the negative electrode S, O-containing film of battery A-8 and the negative electrode S, O-containing film of battery A-9 were analyzed. As a result, a peak indicating the presence of S (FIG. 44) and N A peak indicating the presence of (FIG. 42) was observed. That is, the negative electrode S, O-containing film of Battery A-8 and the negative electrode S, O-containing film of Battery A-9 contained S and N. However, these peaks were not confirmed in the analysis results of the negative electrode film of Battery A-C3. That is, the negative electrode film of Battery A-C3 did not contain an amount exceeding the detection limit for both S and N. It should be noted that peaks indicating the presence of F, C, and O were observed in all the analysis results of the negative electrode S, O-containing film of Battery A-8 and Battery A-9 and the negative electrode film of Battery A-C3. That is, the negative electrode S, O-containing film of Battery A-8 and Battery A-9 and the negative film of Battery A-C3 all contained F, C, and O.
　これらの元素は何れも電解液に由来する成分である。特にＳ、ＯおよびＦは電解液の金属塩に含まれる成分であり、具体的には金属塩のアニオンの化学構造に含まれる成分である。したがって、これらの結果から、各負極Ｓ，Ｏ含有皮膜および負極皮膜には金属塩（つまり支持塩）のアニオンの化学構造に由来する成分が含まれることがわかる。 These elements are all components derived from the electrolytic solution. In particular, S, O and F are components contained in the metal salt of the electrolytic solution, specifically, components contained in the chemical structure of the anion of the metal salt. Therefore, it can be seen from these results that each of the negative electrode S, O-containing film and the negative electrode film contains a component derived from the chemical structure of the anion of the metal salt (that is, the supporting salt).
　図４４に示した硫黄元素（Ｓ）の分析結果について、更に詳細に解析した。電池Ａ－８および電池Ａ－９の分析結果について、ガウス／ローレンツ混合関数を用いてピーク分離を行った。電池Ａ－８の解析結果を図４５に示し、電池Ａ－９の解析結果を図４６に示す。 44. The analysis results of elemental sulfur (S) shown in FIG. 44 were analyzed in more detail. For the analysis results of Battery A-8 and Battery A-9, peak separation was performed using a Gauss / Lorentz mixed function. FIG. 45 shows the analysis result of the battery A-8, and FIG. 46 shows the analysis result of the battery A-9.
　図４５および図４６に示すように、電池Ａ－８および電池Ａ－９の負極Ｓ，Ｏ含有皮膜を分析した結果、１６５～１７５ｅＶ付近に比較的大きなピーク（波形）が観察された。そして、図４５および図４６に示すように、この１７０ｅＶ付近のピーク（波形）は、４つのピークに分離された。そのうちの一つはＳＯ２（Ｓ＝Ｏ構造）の存在を示す１７０ｅＶ付近のピークである。この結果から、本発明のリチウムイオン二次電池において負極表面に形成されているＳ，Ｏ含有皮膜はＳ＝Ｏ構造を有するといえる。そして、この結果と上記のＸＰＳ分析結果とを考慮すると、Ｓ，Ｏ含有皮膜のＳ＝Ｏ構造に含まれるＳは金属塩すなわち支持塩のアニオンの化学構造に含まれるＳだと推測される。 As shown in FIGS. 45 and 46, as a result of analysis of the negative electrode S, O-containing films of Battery A-8 and Battery A-9, a relatively large peak (waveform) was observed in the vicinity of 165 to 175 eV. As shown in FIGS. 45 and 46, the peak (waveform) near 170 eV was separated into four peaks. One of them is a peak around 170 eV indicating the presence of SO 2 (S═O structure). From this result, it can be said that the S, O-containing film formed on the negative electrode surface in the lithium ion secondary battery of the present invention has an S = O structure. In consideration of this result and the above XPS analysis result, it is presumed that S contained in the S═O structure of the S, O-containing coating is S contained in the chemical structure of the metal salt, that is, the anion of the supporting salt.
（負極Ｓ，Ｏ含有皮膜のＳ元素比率）
　上記した負極Ｓ，Ｏ含有皮膜のＸＰＳ分析結果を基に、電池Ａ－８および電池Ａ－９の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ３の負極皮膜における放電時のＳ元素の比率を算出した。具体的には、各々の負極Ｓ，Ｏ含有皮膜および負極皮膜につき、Ｓ、Ｎ、Ｆ、Ｃ、Ｏのピーク強度の総和を１００％としたときのＳの元素比を算出した。結果を表２４に示す。 (S element ratio of negative electrode S, O-containing coating)
Based on the results of XPS analysis of the negative electrode S, O-containing film described above, the ratio of S element during discharge in the negative electrode S, O-containing film of battery A-8 and battery A-9 and the negative electrode film of battery A-C3 was calculated. did. Specifically, for each negative electrode S, O-containing film and negative electrode film, the element ratio of S was calculated when the sum of the peak intensities of S, N, F, C, and O was 100%. The results are shown in Table 24.
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000024
　上記したように電池Ａ－Ｃ３の負極皮膜は検出限界以上のＳを含んでいなかったが、電池Ａ－８の負極Ｓ，Ｏ含有皮膜および電池Ａ－９の負極Ｓ，Ｏ含有皮膜からはＳが検出された。また、電池Ａ－８の負極Ｓ，Ｏ含有皮膜は電池Ａ－９の負極Ｓ，Ｏ含有皮膜に比べて多くのＳを含んでいた。なお、電池Ａ－Ｃ３の負極Ｓ，Ｏ含有皮膜からＳが検出されなかったことから、各電池の負極Ｓ，Ｏ含有皮膜に含まれるＳは正極活物質に含まれる不可避不純物やその他の添加物に由来するものではなく、電解液中の金属塩に由来するものであるといえる。 As described above, the negative electrode film of the battery A-C3 did not contain S exceeding the detection limit, but the negative electrode S, O-containing film of the battery A-8 and the negative electrode S, O-containing film of the battery A-9 S was detected. Further, the negative electrode S, O-containing film of Battery A-8 contained more S than the negative electrode S, O-containing film of Battery A-9. Since S was not detected from the negative electrode S, O-containing film of the battery A-C3, S contained in the negative electrode S, O-containing film of each battery was an inevitable impurity or other additive contained in the positive electrode active material. It can be said that it is derived from the metal salt in the electrolytic solution, not derived from.
　また、電池Ａ－８の負極Ｓ，Ｏ含有皮膜におけるＳ元素比率が１０．４原子％であり、電池Ａ－９の負極Ｓ，Ｏ含有皮膜におけるＳ元素比率が３．７原子％であることから、本発明の非水電解質二次電池において、負極Ｓ，Ｏ含有皮膜におけるＳ元素比率は２．０原子％以上であり、好ましくは２．５原子％以上であり、より好ましくは３．０原子％以上であり、さらに好ましくは３．５原子％以上である。なお、Ｓの元素比率（原子％）とは、上述したようにＳ、Ｎ、Ｆ、Ｃ、Ｏのピーク強度の総和を１００％としたときのＳのピーク強度比を指す。Ｓの元素比率の上限値は特に定めないが、強いて言うとすれば、２５原子％以下であるのが良い。 Further, the S element ratio in the negative electrode S, O-containing film of Battery A-8 is 10.4 atomic%, and the S element ratio in the negative electrode S, O-containing film of Battery A-9 is 3.7 atomic%. Thus, in the nonaqueous electrolyte secondary battery of the present invention, the S element ratio in the negative electrode S, O-containing coating is 2.0 atomic% or more, preferably 2.5 atomic% or more, more preferably 3.0. It is at least atomic percent, more preferably at least 3.5 atomic percent. The elemental ratio (atomic%) of S indicates the peak intensity ratio of S when the sum of the peak intensities of S, N, F, C, and O is 100% as described above. The upper limit value of the element ratio of S is not particularly defined, but to be strong, it should be 25 atomic% or less.
（負極Ｓ，Ｏ含有皮膜の厚さ）
　電池Ａ－８のリチウムイオン二次電池について、１００サイクル充放電を繰り返した後に電圧３．０Ｖの放電状態にしたもの、および、１００サイクル充放電を繰り返した後に電圧４．１Ｖの充電状態にしたものを準備し、上記のＸＰＳ分析の前処理と同様の方法で分析対象となる負極検体を得た。得られた負極検体をＦＩＢ（集束イオンビーム：Ｆｏｃｕｓｅｄ　Ｉｏｎ　Ｂｅａｍ）加工することにより、厚み１００ｎｍ程度のＳＴＥＭ分析用検体を得た。なお、ＦＩＢ加工の前処理として、負極にはＰｔを蒸着した。以上の工程は負極を大気に触れさせることなくおこなった。 (Thickness of negative electrode S, O-containing film)
Regarding the lithium ion secondary battery of Battery A-8, a battery having a voltage of 3.0 V was discharged after repeating 100 cycles of charge and discharge, and a battery having a voltage of 4.1 V was charged after repeating 100 cycles of charge and discharge A sample was prepared, and a negative electrode specimen to be analyzed was obtained by the same method as the pretreatment of the XPS analysis. The obtained negative electrode specimen was processed by FIB (Focused Ion Beam) to obtain a specimen for STEM analysis having a thickness of about 100 nm. In addition, Pt was vapor-deposited on the negative electrode as a pretreatment for FIB processing. The above steps were performed without exposing the negative electrode to the atmosphere.
　各ＳＴＥＭ分析用検体をＥＤＸ（エネルギ分散型Ｘ線分析：Ｅｎｅｒｇｙ　Ｄｉｓｐｅｒｓｉｖｅ　Ｘ－ｒａｙ　ｓｐｅｃｔｒｏｓｃｏｐｙ）装置が付属したＳＴＥＭ（走査透過電子顕微鏡：Ｓｃａｎｎｉｎｇ　Ｔｒａｎｓｍｉｓｓｉｏｎ　Ｅｌｅｃｔｒｏｎ　Ｍｉｃｒｏｓｃｏｐｅ）により分析した。結果を図４７～図５０に示す。このうち図４７はＢＦ（明視野：Ｂｒｉｇｈｔ－ｆｉｅｌｄ）－ＳＴＥＭ像であり、図４８～図５０は、図４７と同じ観察領域のＳＥＴＭ－ＥＤＸによる元素分布像である。さらに、図４８はＣについての分析結果であり、図４９はＯについての分析結果であり、図５０はＳについての分析結果である。なお、図４８～図５０は、放電状態のリチウムイオン二次電池における負極の分析結果である。 Each STEM analysis specimen was analyzed by STEM (Scanning Transmission Electron Microscope) with an EDX (Energy Dispersive X-ray spectroscopy) apparatus. The results are shown in FIGS. Among these, FIG. 47 is a BF (Bright-field) -STEM image, and FIGS. 48 to 50 are element distribution images by the SETM-EDX in the same observation region as FIG. Further, FIG. 48 shows the analysis result for C, FIG. 49 shows the analysis result for O, and FIG. 50 shows the analysis result for S. 48 to 50 show the analysis results of the negative electrode in the discharged lithium ion secondary battery.
　図４７に示すように、ＳＴＥＭ像の左上部には黒色の部分が存在する。この黒色の部分は、ＦＩＢ加工の前処理で蒸着されたＰｔに由来する。各ＳＴＥＭ像において、このＰｔ由来の部分（Ｐｔ部と呼ぶ）よりも上側にある部分は、Ｐｔ蒸着後に汚染された部分とみなし得る。したがって、図４８～図５０においては、Ｐｔ部よりも下側にある部分についてのみ検討した。 47. As shown in FIG. 47, a black portion exists in the upper left part of the STEM image. This black part is derived from Pt deposited in the pretreatment of FIB processing. In each STEM image, a portion above the Pt-derived portion (referred to as a Pt portion) can be regarded as a contaminated portion after Pt deposition. Therefore, in FIGS. 48 to 50, only the portion below the Pt portion was examined.
　図４８に示すように、Ｐｔ部よりも下側において、Ｃは層状をなしていた。これは、負極活物質たる黒鉛の層状構造だと考えられる。図４９において、Ｏは黒鉛の外周および層間に相当する部分にある。図５０においてもまた、Ｓは黒鉛の外周および層間に相当する部分にある。これらの結果から、Ｓ＝Ｏ構造等のＳおよびＯを含有する負極Ｓ，Ｏ含有皮膜は、黒鉛の表面および層間に形成されていると推測される。 As shown in FIG. 48, C was layered below the Pt portion. This is considered to be a layered structure of graphite as a negative electrode active material. In FIG. 49, O exists in the part corresponding to the outer periphery and interlayer of graphite. Also in FIG. 50, S exists in the part corresponding to the outer periphery and interlayer of graphite. From these results, it is surmised that the negative electrode S, O-containing film containing S and O, such as the S═O structure, is formed between the surface and the interlayer of graphite.
　黒鉛の表面に形成されている負極Ｓ，Ｏ含有皮膜を無作為に１０箇所選び、負極Ｓ，Ｏ含有皮膜の厚さを測定し、測定値の平均値を算出した。充電状態のリチウムイオン二次電池における負極についても同様に分析し、各分析結果を基に、黒鉛の表面に形成されている負極Ｓ，Ｏ含有皮膜の厚さの平均値を算出した。結果を表２５に示す。 Ten negative electrode S, O-containing films formed on the surface of graphite were randomly selected, the thickness of the negative electrode S, O-containing film was measured, and the average value of the measured values was calculated. The negative electrode in the charged lithium ion secondary battery was similarly analyzed, and the average value of the thicknesses of the negative electrode S and O-containing coating formed on the surface of the graphite was calculated based on each analysis result. The results are shown in Table 25.
Figure JPOXMLDOC01-appb-T000025
Figure JPOXMLDOC01-appb-T000025
　表２５に示すように、負極Ｓ，Ｏ含有皮膜の厚みは充電後に増加している。この結果から、負極Ｓ，Ｏ含有皮膜には充放電に対して安定して存在する定着部と、充放電に伴って増減する吸着部が存在すると推測される。そして、吸着部が存在することで、負極Ｓ，Ｏ含有皮膜は充放電に際して厚さが増減したと推測される。 As shown in Table 25, the thickness of the negative electrode S, O-containing film increases after charging. From this result, it is presumed that the negative electrode S, O-containing film has a fixing portion that stably exists with respect to charging and discharging and an adsorption portion that increases and decreases with charging and discharging. And it is estimated that the thickness of the negative electrode S, O-containing film increased or decreased during charging / discharging due to the presence of the adsorbing portion.
　（正極皮膜の分析）
　電池Ａ－８のリチウムイオン二次電池について、３サイクル充放電を繰り返した後に電圧３．０Ｖの放電状態にしたもの、３サイクル充放電を繰り返した後に電圧４．１Ｖの充電状態にしたもの、１００サイクル充放電を繰り返した後に電圧３．０Ｖの放電状態にしたもの、１００サイクル充放電を繰り返した後に電圧４．１Ｖの充電状態にしたもの、の４つを準備した。４つの電池Ａ－８のリチウムイオン二次電池について、それぞれ上述したのと同様の方法を用いて、分析対象となる正極を得た。そして得られた各正極をＸＰＳ分析した。結果を図５１および図５２に示す。なお、図５１は酸素元素についての分析結果であり、図５２は硫黄元素についての分析結果である。 (Analysis of positive electrode film)
Regarding the lithium ion secondary battery of battery A-8, a state in which the battery was discharged in a voltage of 3.0 V after repeating three cycles of charge and discharge, and a state in which the battery was charged in a voltage of 4.1 V after repeating the three cycles of charge and discharge, Four were prepared: one that had been charged and discharged at a voltage of 3.0 V after repeating 100 cycles of charge and discharge, and one that was charged at a voltage of 4.1 V after being repeatedly charged and discharged for 100 cycles. For the lithium ion secondary batteries of four batteries A-8, positive electrodes to be analyzed were obtained using the same method as described above. Then, each obtained positive electrode was analyzed by XPS. The results are shown in FIG. 51 and FIG. 51 shows the analysis results for the oxygen element, and FIG. 52 shows the analysis results for the sulfur element.
　図５１および図５２に示すように、電池Ａ－８の正極Ｓ，Ｏ含有皮膜もまた、ＳおよびＯを含むことがわかる。また、図５２には１７０ｅＶ付近のピークが認められるため、電池Ａ－８の正極Ｓ，Ｏ含有皮膜もまた電池Ａ－８の負極Ｓ，Ｏ含有皮膜と同様に本発明の電解液に由来するＳ＝Ｏ構造を有することがわかる。 51 and 52, it can be seen that the positive electrode S, O-containing film of the battery A-8 also contains S and O. In addition, since a peak around 170 eV is recognized in FIG. 52, the positive electrode S, O-containing film of battery A-8 is also derived from the electrolytic solution of the present invention, similarly to the negative electrode S, O-containing film of battery A-8. It can be seen that it has an S = O structure.
　ところで、図５１に示すように、５２９ｅＶ付近に存在するピークの高さはサイクル経過後に減少している。このピークは正極活物質に由来するＯの存在を示すものと考えられ、具体的には、ＸＰＳ分析において正極活物質中のＯ原子で励起された光電子がＳ，Ｏ含有皮膜を通過して検出されたものと考えられる。このピークがサイクル経過後に減少したことから、正極表面に形成されたＳ，Ｏ含有皮膜の厚さはサイクル経過に伴って増大したと考えられる。 By the way, as shown in FIG. 51, the height of the peak existing in the vicinity of 529 eV decreases after the cycle. This peak is considered to indicate the presence of O derived from the positive electrode active material. Specifically, in XPS analysis, photoelectrons excited by O atoms in the positive electrode active material pass through the S, O-containing coating and are detected. It is thought that it was done. Since this peak decreased after the cycle, it is considered that the thickness of the S, O-containing film formed on the positive electrode surface increased with the cycle.
　また、図５１および図５２に示すように、正極Ｓ，Ｏ含有皮膜中のＯおよびＳは放電時に増加し充電時に減少した。この結果から、ＯおよびＳは充放電に伴って正極Ｓ，Ｏ含有皮膜を出入りすると考えられる。そしてこのことから、充放電に際して正極Ｓ，Ｏ含有皮膜中のＳやＯの濃度が増減しているか、または、負極Ｓ，Ｏ含有皮膜と同様に正極Ｓ，Ｏ含有皮膜においても吸着部の存在により厚さが増減すると推測される。 Also, as shown in FIGS. 51 and 52, O and S in the positive electrode S, O-containing film increased during discharging and decreased during charging. From this result, it is considered that O and S enter and leave the positive electrode S and O-containing film with charge and discharge. From this fact, the concentration of S and O in the positive electrode S and O-containing coating is increased or decreased during charging or discharging, or the presence of an adsorbing portion in the positive electrode S and O-containing coating as well as the negative electrode S and O-containing coating. It is estimated that the thickness increases or decreases.
　さらに、電池Ａ－１１のリチウムイオン二次電池についても正極Ｓ，Ｏ含有皮膜および負極Ｓ，Ｏ含有皮膜をＸＰＳ分析した。 Further, the positive electrode S, O-containing film and the negative electrode S, O-containing film were also subjected to XPS analysis for the lithium ion secondary battery of the battery A-11.
　電池Ａ－１１のリチウムイオン二次電池を、２５℃、使用電圧範囲３．０Ｖ～４．１Ｖとし、レート１ＣでＣＣ充放電を５００サイクル繰り返した。５００サイクル後、３．０Ｖの放電状態、および、４．０Ｖの充電状態で正極Ｓ，Ｏ含有皮膜のＸＰＳスペクトルを測定した。また、サイクル試験前（つまり初回充放電後）における３．０Ｖの放電状態の負極Ｓ，Ｏ含有皮膜、および、５００サイクル後における３．０Ｖの放電状態の負極Ｓ，Ｏ含有皮膜について、ＸＰＳによる元素分析をおこない、当該負極Ｓ，Ｏ含有皮膜に含まれるＳ元素比率を算出した。ＸＰＳにより測定された電池Ａ－１１の正極Ｓ，Ｏ含有皮膜の分析結果を図５３および図５４に示す。具体的には、図５３は硫黄元素についての分析結果であり、図５４は酸素元素についての分析結果である。また、ＸＰＳにより測定された負極皮膜のＳ元素比率（原子％）を表２６に示す。なお、Ｓ元素比率は、上記の「負極Ｓ，Ｏ含有皮膜のＳ元素比率」の項と同様に算出した。 The lithium ion secondary battery of battery A-11 was set to 25 ° C., operating voltage range 3.0V to 4.1V, and CC charge / discharge was repeated 500 cycles at a rate of 1C. After 500 cycles, the XPS spectrum of the positive electrode S, O-containing film was measured in a discharge state of 3.0 V and a charge state of 4.0 V. Further, the negative electrode S, O-containing coating in the 3.0V discharge state before the cycle test (that is, after the first charge / discharge) and the negative electrode S, O-containing coating in the 3.0V discharge state after 500 cycles are measured by XPS. Elemental analysis was performed, and the S element ratio contained in the negative electrode S, O-containing film was calculated. 53 and 54 show the analysis results of the positive electrode S, O-containing film of the battery A-11 measured by XPS. Specifically, FIG. 53 shows the analysis result for sulfur element, and FIG. 54 shows the analysis result for oxygen element. Table 26 shows the S element ratio (atomic%) of the negative electrode film measured by XPS. The S element ratio was calculated in the same manner as the above-mentioned item “S element ratio of negative electrode S, O-containing film”.
　図５３および図５４に示すように、電池Ａ－１１のリチウムイオン二次電池における正極Ｓ，Ｏ含有皮膜からもまた、Ｓの存在を示すピークおよびＯの存在を示すピークが検出された。また、ＳのピークおよびＯのピークが何れも放電時に増大し充電時に減少していた。この結果からも、正極Ｓ，Ｏ含有皮膜がＳ＝Ｏ構造を有し、正極Ｓ，Ｏ含有皮膜中のＯおよびＳは充放電に伴って正極Ｓ，Ｏ含有皮膜を出入りすることが裏付けられる。 As shown in FIG. 53 and FIG. 54, a peak indicating the presence of S and a peak indicating the presence of O were also detected from the positive electrode S, O-containing film in the lithium ion secondary battery of battery A-11. In addition, both the S peak and the O peak increased during discharging and decreased during charging. This result also confirms that the positive electrode S, O-containing film has an S = O structure, and O and S in the positive electrode S, O-containing film enter and exit the positive electrode S, O-containing film with charge and discharge. .
Figure JPOXMLDOC01-appb-T000026
Figure JPOXMLDOC01-appb-T000026
　また、表２６に示すように、電池Ａ－１１の負極Ｓ，Ｏ含有皮膜は、初回充放電後にも、５００サイクル経過後にも、２．０原子％以上のＳを含んでいた。この結果から、本発明の非水電解質二次電池における負極Ｓ，Ｏ含有皮膜は、サイクル経過前であってもサイクル経過後であっても２．０原子％以上のＳを含むことがわかる。 Further, as shown in Table 26, the negative electrode S, O-containing film of the battery A-11 contained 2.0 atomic% or more of S even after the first charge / discharge and after 500 cycles. From this result, it can be seen that the negative electrode S, O-containing film in the nonaqueous electrolyte secondary battery of the present invention contains 2.0 atomic% or more of S before or after the cycle.
　電池Ａ－１１～電池Ａ－１４および電池Ａ－Ｃ４、電池Ａ－Ｃ５のリチウムイオン二次電池について、６０℃で１週間貯蔵する高温貯蔵試験を行い、当該高温貯蔵試験後の各電池Ａ－１１～Ａ－１４の正極Ｓ，Ｏ含有皮膜および負極Ｓ，Ｏ含有皮膜、ならびに、各電池Ａ－Ｃ４、Ａ－Ｃ５の正極皮膜および負極皮膜を分析した。高温貯蔵試験開始前に、３．０Ｖから４．１Ｖにまでレート０．３３ＣでＣＣ－ＣＶ充電した。このときの充電容量を基準（ＳＯＣ１００）とし、当該基準に対して２０％分をＣＣ放電してＳＯＣ８０に調整した後、高温貯蔵試験を開始した。高温貯蔵試験後に１Ｃで３．０ＶまでＣＣ－ＣＶ放電した。そして、放電後の正極Ｓ，Ｏ含有皮膜および負極Ｓ，Ｏ含有皮膜ならびに正極皮膜および負極皮膜のＸＰＳスペクトルを測定した。ＸＰＳにより測定された電池Ａ－１１～電池Ａ－１４の正極Ｓ，Ｏ含有皮膜、ならびに、電池Ａ－Ｃ４および電池Ａ－Ｃ５の正極皮膜の分析結果を図５５～図５８に示す。また、ＸＰＳにより測定された電池Ａ－１１～電池Ａ－１４の負極Ｓ，Ｏ含有皮膜、ならびに、電池Ａ－Ｃ４および電池Ａ－Ｃ５の負極皮膜の分析結果を図５９～図６２に示す。 The batteries A-11 to A-14, the batteries A-C4, and the batteries A-C5 were subjected to a high-temperature storage test in which they were stored at 60 ° C. for 1 week, and each battery A- The positive electrode S, O-containing film and negative electrode S, O-containing film of 11 to A-14, and the positive electrode film and negative electrode film of each of the batteries A-C4 and A-C5 were analyzed. Before starting the high temperature storage test, CC-CV charge was performed at a rate of 0.33 C from 3.0 V to 4.1 V. The charge capacity at this time was set as a standard (SOC100), 20% of the standard was CC discharged and adjusted to SOC80, and then a high-temperature storage test was started. After the high temperature storage test, CC-CV discharge was performed to 3.0V at 1C. And the XPS spectrum of the positive electrode S, O containing film | membrane and negative electrode S, O containing film | membrane after a discharge and a positive electrode film | membrane and a negative electrode film | membrane was measured. The analysis results of the positive electrode S, O-containing coatings of batteries A-11 to A-14 and the positive coatings of batteries A-C4 and A-C5 measured by XPS are shown in FIGS. Further, FIGS. 59 to 62 show analysis results of the negative electrode S, O-containing coatings of the batteries A-11 to A-14 and the negative coatings of the batteries A-C4 and A-C5 measured by XPS.
　具体的には、図５５は電池Ａ－１１、電池Ａ－１２の正極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ４の正極皮膜の硫黄元素についての分析結果である。図５６は電池Ａ－１３、電池Ａ－１４の正極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ５の正極皮膜の硫黄元素についての分析結果である。図５７は電池Ａ－１１、電池Ａ－１２の正極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ４の正極皮膜の酸素元素についての分析結果である。図５８は電池Ａ－１３、電池Ａ－１４の正極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ５の正極皮膜の酸素元素についての分析結果である。また、図５９は電池Ａ－１１、電池Ａ－１２の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ４の負極皮膜の硫黄元素についての分析結果である。図６０は電池Ａ－１３、電池Ａ－１４の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ５の負極皮膜の硫黄元素についての分析結果である。図６１は電池Ａ－１１、電池Ａ－１２の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ４の負極皮膜の酸素元素についての分析結果である。図６２は電池Ａ－１３、電池Ａ－１４の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ５の負極皮膜の酸素元素についての分析結果である。 Specifically, FIG. 55 shows the analysis results for the elemental sulfur of the positive electrode S, O-containing film of the battery A-11 and the battery A-12 and the positive electrode film of the battery A-C4. FIG. 56 shows analysis results of elemental sulfur in the positive electrode S, O-containing coatings of batteries A-13 and A-14 and the positive coating of batteries A-C5. FIG. 57 shows the results of analysis of oxygen elements in the positive electrode S, O-containing coatings of batteries A-11 and A-12 and the positive coating of batteries A-C4. FIG. 58 shows the analysis results of oxygen elements in the positive electrode S, O-containing coatings of batteries A-13 and A-14 and the positive coating of batteries A to C5. FIG. 59 shows the results of analysis of sulfur elements in the negative electrode S, O-containing coatings of batteries A-11 and A-12 and the negative coatings of batteries A-C4. FIG. 60 shows the analysis results for the elemental sulfur in the negative electrode S, O-containing coatings of batteries A-13 and A-14 and the negative coating of batteries A-C5. FIG. 61 shows the analysis results of oxygen elements in the negative electrode S, O-containing coatings of batteries A-11 and A-12 and the negative coating of batteries A-C4. FIG. 62 shows the analysis results of oxygen elements in the negative electrode S, O-containing coatings of batteries A-13 and A-14 and the negative coating of batteries A-C5.
　図５５および図５６に示すように、従来の電解液を用いた電池Ａ－Ｃ４および電池Ａ－Ｃ５のリチウムイオン二次電池は正極皮膜にＳを含まないのに対して、本発明の電解液を用いた電池Ａ－１１～電池Ａ－１４のリチウムイオン二次電池は正極Ｓ，Ｏ含有皮膜にＳを含んでいた。また、図５７および図５８に示すように、電池Ａ－１１～電池Ａ－１４のリチウムイオン二次電池は何れも正極Ｓ，Ｏ含有皮膜にＯを含んでいた。さらに、図５５および図５６に示すように、電池Ａ－１１～電池Ａ－１４のリチウムイオン二次電池における正極Ｓ，Ｏ含有皮膜からは、何れも、ＳＯ２（Ｓ＝Ｏ構造）の存在を示す１７０ｅＶ付近のピークが検出された。これらの結果から、本発明のリチウムイオン二次電池においては、電解液用の有機溶媒としてＡＮを用いた場合にも、ＤＭＣを用いた場合にも、ＳとＯとを含む安定した正極Ｓ，Ｏ含有皮膜が形成されることがわかる。また、この正極Ｓ，Ｏ含有皮膜は負極バインダの種類に影響されないことから、正極Ｓ，Ｏ含有皮膜中のＯはＣＭＣに由来するものではないと考えられる。さらに、図５７および図５８に示すように、電解液用の有機溶媒としてＤＭＣを用いる場合には、５３０ｅＶ付近に、正極活物質由来のＯピークが検出された。このため、電解液用の有機溶媒としてＤＭＣを用いる場合には、ＡＮを用いる場合に比べて正極Ｓ，Ｏ含有皮膜の厚さが薄くなると考えられる。 As shown in FIGS. 55 and 56, the lithium ion secondary batteries of batteries A-C4 and batteries A-C5 using the conventional electrolyte solution do not contain S in the positive electrode film, whereas the electrolyte solution of the present invention Lithium ion secondary batteries of batteries A-11 to A-14 using the above materials contained S in the positive electrode S, O-containing film. As shown in FIGS. 57 and 58, all of the lithium ion secondary batteries of the batteries A-11 to A-14 contained O in the positive electrode S, O-containing coating. Further, as shown in FIGS. 55 and 56, the positive electrode S and O-containing films in the lithium ion secondary batteries of the batteries A-11 to A-14 all have SO 2 (S═O structure). A peak in the vicinity of 170 eV was detected. From these results, in the lithium ion secondary battery of the present invention, the stable positive electrode S containing S and O, both when AN is used as the organic solvent for the electrolyte and when DMC is used, It can be seen that an O-containing film is formed. Moreover, since this positive electrode S, O containing film is not influenced by the kind of negative electrode binder, it is thought that O in the positive electrode S, O containing film does not originate in CMC. Further, as shown in FIGS. 57 and 58, when DMC was used as the organic solvent for the electrolyte, an O peak derived from the positive electrode active material was detected in the vicinity of 530 eV. For this reason, when DMC is used as the organic solvent for the electrolytic solution, it is considered that the thickness of the positive electrode S, O-containing film is thinner than when AN is used.
　同様に、図５９～図６２から、電池Ａ－１１～電池Ａ－１４のリチウムイオン二次電池は負極Ｓ，Ｏ含有皮膜にもＳおよびＯを含み、これらはＳ＝Ｏ構造をなしかつ電解液に由来することがわかる。そしてこの負極Ｓ，Ｏ含有皮膜は、電解液用の有機溶媒としてＡＮを用いた場合にもＤＭＣを用いた場合にも形成されることがわかる。 Similarly, from FIGS. 59 to 62, the lithium ion secondary batteries of the batteries A-11 to A-14 also contain S and O in the negative electrode S and O-containing coating, which have an S═O structure and are electrolyzed. It turns out that it originates in a liquid. And it turns out that this negative electrode S and O containing film | membrane is formed even when AN is used as an organic solvent for electrolyte solutions, and also when DMC is used.
　電池Ａ－１１、電池Ａ－１２および電池Ａ－Ｃ４のリチウムイオン二次電池について、上記の高温貯蔵試験および放電後の各負極Ｓ，Ｏ含有皮膜ならびに負極皮膜のＸＰＳスペクトルを測定し、電池Ａ－１１、電池Ａ－１２の負極Ｓ，Ｏ含有皮膜および電池Ａ－Ｃ４の負極皮膜における放電時のＳ元素の比率を算出した。具体的には、各々の負極Ｓ，Ｏ含有皮膜または負極皮膜につき、Ｓ、Ｎ、Ｆ、Ｃ、Ｏのピーク強度の総和を１００％としたときのＳの元素比を算出した。結果を表２７に示す。 For the lithium ion secondary batteries of Battery A-11, Battery A-12, and Battery A-C4, the XPS spectrum of each of the negative electrode S and O-containing coatings and the negative electrode coatings after the high-temperature storage test and discharge was measured. -11, the ratio of S element during discharge in the negative electrode S, O-containing film of battery A-12 and the negative electrode film of battery A-C4 was calculated. Specifically, for each negative electrode S, O-containing film or negative electrode film, the element ratio of S was calculated when the sum of the peak intensities of S, N, F, C, and O was 100%. The results are shown in Table 27.
Figure JPOXMLDOC01-appb-T000027
Figure JPOXMLDOC01-appb-T000027
　表２７に示すように、電池Ａ－Ｃ４の負極皮膜は検出限界以上のＳを含んでいなかったが、電池Ａ－１１および電池Ａ－１２の負極Ｓ，Ｏ含有皮膜からはＳが検出された。また、電池Ａ－１２の負極Ｓ，Ｏ含有皮膜は電池Ａ－１１の負極Ｓ，Ｏ含有皮膜に比べて多くのＳを含んでいた。また、この結果から、高温貯蔵後においても負極Ｓ，Ｏ含有皮膜におけるＳ元素比率は２．０原子％以上であることがわかる。 As shown in Table 27, the negative electrode film of Battery A-C4 did not contain S exceeding the detection limit, but S was detected from the negative electrode S, O-containing film of Battery A-11 and Battery A-12. It was. Further, the negative electrode S, O-containing film of Battery A-12 contained more S than the negative electrode S, O-containing film of Battery A-11. Further, from this result, it is understood that the S element ratio in the negative electrode S, O-containing film is 2.0 atomic% or more even after high temperature storage.
（評価例Ａ－２０：電池のサイクル耐久性）
　電池Ａ－１１、電池Ａ－１２、電池Ａ－１５および電池Ａ－Ｃ４の各リチウムイオン二次電池について、室温、３．０Ｖ～４．１Ｖ(ｖｓ．Ｌｉ基準)の範囲でＣＣ充放電を繰り返し、初回充放電時の放電容量、１００サイクル時の放電容量、および５００サイクル時の放電容量を測定した。そして、初回充放電時の各リチウムイオン二次電池の容量を１００％とし、１００サイクル時および５００サイクル時の各リチウムイオン二次電池の容量維持率（％）を算出した。結果を表２８に示す。 (Evaluation Example A-20: Cycle durability of the battery)
For each of the lithium ion secondary batteries of battery A-11, battery A-12, battery A-15, and battery A-C4, charge / discharge CC at room temperature in the range of 3.0 V to 4.1 V (vs. Li standard). Repeatedly, the discharge capacity at the first charge / discharge, the discharge capacity at 100 cycles, and the discharge capacity at 500 cycles were measured. And the capacity | capacitance maintenance factor (%) of each lithium ion secondary battery at the time of 100 cycles and 500 cycles was computed by making the capacity | capacitance of each lithium ion secondary battery at the time of initial charge / discharge into 100%. The results are shown in Table 28.
Figure JPOXMLDOC01-appb-T000028
Figure JPOXMLDOC01-appb-T000028
　表２８に示すように、電池Ａ－１１、電池Ａ－１２および電池Ａ－１５のリチウムイオン二次電池は、ＳＥＩの材料となるＥＣを含まないにも拘わらず、ＥＣを含む電池Ａ－Ｃ４のリチウムイオン二次電池と同等の容量維持率を示した。これは、各電池のリチウムイオン二次電池における正極および負極には、本発明の電解液に由来するＳ，Ｏ含有皮膜が存在するためだと考えられる。そして、電池Ａ－１１のリチウムイオン二次電池については、特に５００サイクル経過時にも極めて高い容量維持率を示し、特に耐久性に優れていた。この結果から、有機溶媒としてＤＭＣを選択する場合には、ＡＮを選択する場合に比べて、より耐久性が向上するといえる。 As shown in Table 28, the lithium ion secondary batteries of the battery A-11, the battery A-12, and the battery A-15 did not contain EC that is a material of SEI, but included batteries A-C4 containing EC. Capacity retention rate equivalent to that of the lithium ion secondary battery. This is presumably because the S and O containing film derived from the electrolytic solution of the present invention exists in the positive electrode and the negative electrode in the lithium ion secondary battery of each battery. The lithium ion secondary battery of the battery A-11 showed an extremely high capacity retention rate even after 500 cycles had elapsed, and was particularly excellent in durability. From this result, it can be said that when DMC is selected as the organic solvent, the durability is further improved as compared with the case where AN is selected.
　電池Ａ－１１、電池Ａ－１２および電池Ａ－Ｃ４のリチウムイオン二次電池について、６０℃で１週間貯蔵する高温貯蔵試験を行った。高温貯蔵試験開始前に、３．０Ｖから４．１ＶにまでＣＣ－ＣＶ（定電流定電圧）充電した。このときの充電容量を基準（ＳＯＣ１００）とし、当該基準に対して２０％分をＣＣ放電してＳＯＣ８０に調整した後、高温貯蔵試験を開始した。高温貯蔵試験後に１Ｃで３．０ＶまでＣＣ－ＣＶ放電した。このときの放電容量と貯蔵前のＳＯＣ８０容量との比から、次式のように残存容量を算出した。結果を表２９に示す。 The lithium ion secondary batteries of Battery A-11, Battery A-12, and Battery A-C4 were subjected to a high-temperature storage test that was stored at 60 ° C. for 1 week. Before starting the high-temperature storage test, CC-CV (constant current constant voltage) charging was performed from 3.0 V to 4.1 V. The charge capacity at this time was set as a standard (SOC100), 20% of the standard was CC discharged and adjusted to SOC80, and then a high-temperature storage test was started. After the high temperature storage test, CC-CV discharge was performed to 3.0V at 1C. From the ratio of the discharge capacity at this time and the SOC 80 capacity before storage, the remaining capacity was calculated as follows. The results are shown in Table 29.
　残存容量＝１００×(貯蔵後のＣＣ－ＣＶ放電容量)／(貯蔵前のＳＯＣ８０容量) Residual capacity = 100 x (CC-CV discharge capacity after storage) / (SOC 80 capacity before storage)
Figure JPOXMLDOC01-appb-T000029
Figure JPOXMLDOC01-appb-T000029
　電池Ａ－１１および電池Ａ－１２の非水電解質二次電池の残存容量は、電池Ａ－Ｃ４の非水電解質二次電池の残存容量に比べて大きい。この結果から、本発明の電解液に由来し正極および負極に形成されたＳ，Ｏ含有皮膜が、残存容量増大にも寄与するといえる。 The remaining capacity of the nonaqueous electrolyte secondary batteries of the batteries A-11 and A-12 is larger than the remaining capacity of the nonaqueous electrolyte secondary battery of the batteries A to C4. From this result, it can be said that the S, O-containing coating derived from the electrolytic solution of the present invention and formed on the positive electrode and the negative electrode contributes to an increase in the remaining capacity.
（評価例Ａ－２１：Ａｌ集電体の表面分析）
　電池Ａ－８および電池Ａ－９のリチウムイオン二次電池を、使用電圧範囲３Ｖ～４．２Ｖとし、レート１Ｃで充放電を１００回繰り返し、充放電１００回後に解体し、正極用集電体であるアルミニウム箔を各々取り出し、アルミニウム箔の表面をジメチルカーボネートで洗浄した。 (Evaluation Example A-21: Surface Analysis of Al Current Collector)
The lithium ion secondary batteries of Battery A-8 and Battery A-9 were set to a working voltage range of 3 V to 4.2 V, and were repeatedly charged and discharged 100 times at a rate of 1 C. After 100 times of charging and discharging, they were disassembled, and a current collector for positive electrode Each aluminum foil was taken out and the surface of the aluminum foil was washed with dimethyl carbonate.
　洗浄後の電池Ａ－８および電池Ａ－９のリチウムイオン二次電池のアルミニウム箔の表面を、ＡｒスパッタでエッチングしながらＸ線光電子分光法（ＸＰＳ）にて表面分析を行った。電池Ａ－８および電池Ａ－９のリチウムイオン二次電池の充放電後のアルミニウム箔の表面分析結果を図６３および図６４に示す。 The surface of the aluminum foil of the lithium ion secondary batteries of Battery A-8 and Battery A-9 after washing was subjected to surface analysis by X-ray photoelectron spectroscopy (XPS) while etching by Ar sputtering. 63 and 64 show the surface analysis results of the aluminum foil after charging and discharging of the lithium ion secondary batteries of Battery A-8 and Battery A-9.
　図６３および図６４を比べると、電池Ａ－８および電池Ａ－９のリチウムイオン二次電池の充放電後の正極用集電体であるアルミニウム箔の表面分析結果は両者ともほぼ同じであり、以下のことがいえる。アルミニウム箔の表面において、最表面のＡｌの化学状態はＡｌＦ３であった。アルミニウム箔を深さ方向にエッチングしていくと、Ａｌ、Ｏ、Ｆのピークが検出された。アルミニウム箔を表面から１回～３回エッチングしていった箇所では、Ａｌの化学状態はＡｌ－Ｆ結合およびＡｌ－Ｏ結合の複合状態であることがわかった。さらにエッチングしていくと４回エッチング（ＳｉＯ２換算で深さ約２５ｎｍ）したところからＯ、Ｆのピークが消失し、Ａｌのみのピークが観察された。なお、ＸＰＳ測定データにおいて、ＡｌＦ３は、Ａｌピーク位置７６．３ｅＶに観察され、純Ａｌは、Ａｌピーク位置７３ｅＶに観察され、Ａｌ－Ｆ結合およびＡｌ－Ｏ結合の複合状態では、Ａｌピーク位置７４ｅＶ～７６．３ｅＶに観察される。図６３および図６４に示す破線は、ＡｌＦ３、Ａｌ、Ａｌ２Ｏ３それぞれの代表的なピーク位置を示す。 Comparing FIG. 63 and FIG. 64, the surface analysis results of the aluminum foil as the positive electrode current collector of the lithium ion secondary batteries of the batteries A-8 and A-9 were almost the same. The following can be said. On the surface of the aluminum foil, the chemical state of Al on the outermost surface was AlF 3 . When the aluminum foil was etched in the depth direction, peaks of Al, O, and F were detected. It was found that the chemical state of Al was a composite state of Al—F bond and Al—O bond at the place where the aluminum foil was etched once to three times from the surface. As the etching was further continued, the O and F peaks disappeared from the fourth etching (depth about 25 nm in terms of SiO 2 ), and only the Al peak was observed. In the XPS measurement data, AlF 3 is observed at the Al peak position 76.3 eV, pure Al is observed at the Al peak position 73 eV, and in the combined state of Al—F bond and Al—O bond, the Al peak position is observed. Observed at 74 eV-76.3 eV. The broken lines shown in FIGS. 63 and 64 show typical peak positions of AlF 3 , Al, and Al 2 O 3, respectively.
　以上の結果から、本発明の充放電後のリチウムイオン二次電池のアルミニウム箔の表面には、深さ方向に約２５ｎｍの厚みで、Ａｌ－Ｆ結合（ＡｌＦ３と推測される）の層と、Ａｌ－Ｆ結合（ＡｌＦ３と推測される）およびＡｌ－Ｏ結合（Ａｌ２Ｏ３と推測される）の混在する層とが形成されていることが確認できた。 From the above results, the surface of the aluminum foil of the lithium ion secondary battery after charging and discharging according to the present invention has an Al—F bond (presumed to be AlF 3 ) layer with a thickness of about 25 nm in the depth direction. It was confirmed that an Al—F bond (presumed to be AlF 3 ) and an Al—O bond (presumed to be Al 2 O 3 ) were formed.
　つまり、正極集電体にアルミニウム箔を用いた本発明のリチウムイオン二次電池において、本発明の電解液を用いても充放電後にはアルミニウム箔の最表面にはＡｌ－Ｆ結合（ＡｌＦ３と推測される）からなる不動態膜が形成されることがわかった。 That is, in the lithium ion secondary battery of the present invention using the aluminum foil as the positive electrode current collector, the Al—F bond (AlF 3 It was found that a passive film consisting of
　評価例Ａ－２１の結果から、本発明の電解液と、アルミニウムまたはアルミニウム合金からなる正極用集電体とを組み合わせるリチウムイオン二次電池では、充放電により正極用集電体の表面には不動態膜が形成され、なおかつ、高電位状態においても正極用集電体からのＡｌの溶出が抑制されることがわかった。 From the results of Evaluation Example A-21, in the lithium ion secondary battery in which the electrolyte solution of the present invention and the positive electrode current collector made of aluminum or an aluminum alloy are combined, the surface of the positive electrode current collector is not charged due to charging / discharging. It was found that a dynamic film was formed and that the elution of Al from the positive electrode current collector was suppressed even in a high potential state.
（評価例Ａ－２２：正極Ｓ，Ｏ含有皮膜分析）
　ＴＯＦ－ＳＩＭＳ（Ｔｉｍｅ－ｏｆ－Ｆｌｉｇｈｔ　Ｓｅｃｏｎｄａｒｙ　Ｉｏｎ　Ｍａｓｓ　Ｓｐｅｃｔｒｏｍｅｔｒｙ：飛行時間型二次イオン質量分析法）を用いて、電池Ａ－１１の正極Ｓ，Ｏ含有皮膜に含まれる各分子の構造情報を分析した。 (Evaluation Example A-22: Analysis of coating film containing positive electrode S and O)
Using TOF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry), the structural information of each molecule contained in the positive electrode S, O-containing film of Battery A-11 was analyzed. .
　電池Ａ－１１の非水電解質二次電池を２５℃で３サイクル充放電した後、３Ｖ放電状態で解体し正極を取り出した。これとは別に、電池Ａ－１１の非水電解質二次電池を２５℃で５００サイクル充放電した後、３Ｖ放電状態で解体し正極を取り出した。さらにこれとは別に、電池Ａ－１１の非水電解質二次電池を２５℃で３サイクル充放電した後、６０℃で一か月間放置し、３Ｖ放電状態で解体し正極を取り出した。各正極をＤＭＣで３回洗浄し、分析用の正極を得た。なお、当該正極には正極Ｓ，Ｏ含有皮膜が形成され、以下の分析では正極Ｓ，Ｏ含有皮膜に含まれる分子の構造情報が分析された。 The nonaqueous electrolyte secondary battery of battery A-11 was charged and discharged at 25 ° C. for 3 cycles, then disassembled in a 3V discharge state, and the positive electrode was taken out. Separately, the nonaqueous electrolyte secondary battery of Battery A-11 was charged and discharged for 500 cycles at 25 ° C., then disassembled in a 3 V discharge state, and the positive electrode was taken out. Separately from this, the non-aqueous electrolyte secondary battery of Battery A-11 was charged and discharged at 25 ° C. for 3 cycles, then left at 60 ° C. for 1 month, disassembled in a 3 V discharge state, and the positive electrode was taken out. Each positive electrode was washed with DMC three times to obtain a positive electrode for analysis. In addition, the positive electrode S and O containing film was formed in the said positive electrode, and the structural information of the molecule | numerator contained in the positive electrode S and O containing film was analyzed in the following analysis.
　分析用の各正極を、ＴＯＦ－ＳＩＭＳにより分析した。質量分析計としては飛行時間型二次イオン質量分析計を用い、正二次イオンおよび負二次イオンを測定した。一次イオン源としてはＢｉを用い、一次加速電圧は２５ｋＶであった。スパッタイオン源としてはＡｒ－ＧＣＩＢ（Ａｒ１５００）を用いた。測定結果を表３０～表３２に示す。なお、表３１における各フラグメントの正イオン強度（相対値）とは、検出された全てのフラグメントの正イオン強度の総和を１００％とした相対値である。同様に、表３２に記載した各フラグメントの負イオン強度（相対値）とは、検出された全てのフラグメントの負イオン強度の総和を１００％とした相対値である。 Each positive electrode for analysis was analyzed by TOF-SIMS. A time-of-flight secondary ion mass spectrometer was used as a mass spectrometer, and positive secondary ions and negative secondary ions were measured. Bi was used as the primary ion source, and the primary acceleration voltage was 25 kV. Ar-GCIB (Ar1500) was used as the sputter ion source. The measurement results are shown in Tables 30 to 32. In Table 31, the positive ion intensity (relative value) of each fragment is a relative value with the total positive ion intensity of all detected fragments as 100%. Similarly, the negative ionic strength (relative value) of each fragment described in Table 32 is a relative value where the sum of the negative ionic strengths of all detected fragments is 100%.
Figure JPOXMLDOC01-appb-T000030
Figure JPOXMLDOC01-appb-T000030
Figure JPOXMLDOC01-appb-T000031
Figure JPOXMLDOC01-appb-T000031
Figure JPOXMLDOC01-appb-T000032
Figure JPOXMLDOC01-appb-T000032
　表３０に示すように電解液の溶媒由来と推定されるフラグメントは、正二次イオンとして検出されたＣ３Ｈ３およびＣ４Ｈ３のみであった。また、電解液の塩由来と推定されるフラグメントは、主に負二次イオンとして検出され、上記した溶媒由来のフラグメントに比べてイオン強度が大きい。さらに、Ｌｉを含むフラグメントは主に正二次イオンとして検出され、Ｌｉを含むフラグメントのイオン強度は、正二次イオンおよび負二次イオンのなかでも大きな割合を占める。 As shown in Table 30, the fragments presumed to be derived from the solvent of the electrolytic solution were only C 3 H 3 and C 4 H 3 detected as positive secondary ions. In addition, a fragment presumed to be derived from a salt of the electrolytic solution is mainly detected as a negative secondary ion, and has a higher ionic strength than the above-described fragment derived from a solvent. Furthermore, fragments containing Li are mainly detected as positive secondary ions, and the ionic strength of the fragments containing Li accounts for a large proportion of positive secondary ions and negative secondary ions.
　以上のことから、本発明のＳ，Ｏ含有皮膜の主成分は電解液に含まれる金属塩由来の成分であり、かつ、本発明のＳ，Ｏ含有皮膜には多くのＬｉが含まれると推測される。 From the above, it is speculated that the main component of the S, O-containing coating of the present invention is a component derived from the metal salt contained in the electrolytic solution, and that the S, O-containing coating of the present invention contains a large amount of Li. Is done.
　さらに、表３０に示すように、塩由来と推定されるフラグメントとしてはＳＮＯ２，ＳＦＯ２，Ｓ２Ｆ２ＮＯ４等も検出されている。これらは何れもＳ＝Ｏ構造を有し、かつＳに対してＮやＦが結合した構造である。つまり、本発明のＳ，Ｏ含有皮膜において、ＳはＯと二重結合しているだけでなく、ＳＮＯ２，ＳＦＯ２，Ｓ２Ｆ２ＮＯ４等のように、他の元素と結合した構造をもとり得る。したがって、本発明のＳ，Ｏ含有皮膜は少なくともＳ＝Ｏ構造を有していれば良く、Ｓ＝Ｏ構造に含まれるＳが他の元素と結合していても良いといえる。なお、当然乍ら、本発明のＳ，Ｏ含有皮膜はＳ＝Ｏ構造をとらないＳおよびＯを含んでいても良い。 Furthermore, as shown in Table 30, SNO 2 , SFO 2 , S 2 F 2 NO 4 and the like have also been detected as fragments presumed to be derived from salts. Each of these has an S═O structure, and N or F is bonded to S. That is, in the S, O-containing film of the present invention, S is not only double-bonded with O, but also has a structure bonded to other elements such as SNO 2 , SFO 2 , S 2 F 2 NO 4, etc. Can also be taken. Therefore, it can be said that the S, O-containing coating of the present invention has at least an S═O structure, and S contained in the S═O structure may be bonded to other elements. Naturally, the S, O-containing coating of the present invention may contain S and O which do not take the S = O structure.
　ところで、例えば上述した特開２０１３－１４５７３２に紹介されている従来型の電解液、つまり、有機溶媒としてのＥＣと金属塩としてのＬｉＰＦ６と添加剤としてＬｉＦＳＡとを含有する従来の電解液では、Ｓは有機溶媒の分解物に取り込まれる。このためＳは、負極皮膜および／または正極皮膜中においてＣｐＨｑＳ（ｐ、ｑはそれぞれ独立した整数）等のイオンとして存在すると考えられる。これに対して、表３０～表３２に示すように、本発明のＳ，Ｏ含有皮膜から検出されたＳを含有するフラグメントは、ＣｐＨｑＳフラグメントではなくアニオン構造を反映したフラグメントが主体である。このことからも、本発明のＳ，Ｏ含有皮膜が従来の非水電解質二次電池に形成される皮膜とは根本的に異なることが明らかになる。 By the way, in the conventional electrolyte solution introduced in, for example, the above-mentioned JP2013-145732, that is, a conventional electrolyte solution containing EC as an organic solvent, LiPF 6 as a metal salt, and LiFSA as an additive, S is taken into the decomposition product of the organic solvent. For this reason, S is considered to exist as ions such as C p H q S (p and q are independent integers) in the negative electrode film and / or the positive electrode film. On the other hand, as shown in Tables 30 to 32, the fragment containing S detected from the S, O-containing film of the present invention is not a C p H q S fragment but mainly a fragment reflecting an anion structure. It is. This also reveals that the S, O-containing coating of the present invention is fundamentally different from a coating formed on a conventional nonaqueous electrolyte secondary battery.
（電池Ａ１）
　電解液Ｅ８を用いたハーフセルを以下のとおり製造した。
　径１３．８２ｍｍ、面積１．５ｃｍ２、厚み２０μｍのアルミニウム箔（ＪＩＳ　Ａ１０００番系）を作用極とし、対極は金属Ｌｉとした。セパレータは、厚み４００μｍのＷｈａｔｍａｎガラスフィルター不織布：品番１８２５－０５５を用いた。
　作用極、対極、セパレータおよび電解液を電池ケース（宝泉株式会社製　ＣＲ２０３２型コインセルケース）に収容しハーフセルを構成した。これを電池Ａ１のハーフセルとした。 (Battery A1)
A half cell using the electrolytic solution E8 was produced as follows.
An aluminum foil (JIS A1000 series) having a diameter of 13.82 mm, an area of 1.5 cm 2 and a thickness of 20 μm was used as a working electrode, and the counter electrode was metal Li. As the separator, Whatman glass filter nonwoven fabric having a thickness of 400 μm: product number 1825-055 was used.
A working electrode, a counter electrode, a separator, and an electrolytic solution were housed in a battery case (CR2032-type coin cell case manufactured by Hosen Co., Ltd.) to form a half cell. This was made into the half cell of battery A1.
（電池Ａ２）
　電解液Ｅ１１を用いた以外は、電池Ａ１のハーフセルと同様にして、電池Ａ２のハーフセルを作製した。 (Battery A2)
A half cell of the battery A2 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E11 was used.
（電池Ａ３）
　電解液Ｅ１６を用いた以外は、電池Ａ１のハーフセルと同様にして、電池Ａ３のハーフセルを作製した。 (Battery A3)
A half cell of the battery A3 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E16 was used.
（電池Ａ４）
　電解液Ｅ１９を用いた以外は、電池Ａ１のハーフセルと同様にして、電池Ａ４のハーフセルを作製した。 (Battery A4)
A half cell of the battery A4 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E19 was used.
（電池Ａ５）
　電解液Ｅ１３を用いた以外は、電池Ａ１のハーフセルと同様にして、電池Ａ５のハーフセルを作製した。 (Battery A5)
A half cell of the battery A5 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution E13 was used.
（電池ＡＣ１）
　電解液Ｃ５を用いた以外は、電池Ａ１のハーフセルと同様にして、電池ＡＣ１のハーフセルを作製した。 (Battery AC1)
A half cell of the battery AC1 was produced in the same manner as the half cell of the battery A1, except that the electrolytic solution C5 was used.
（電池ＡＣ２）
　電池Ｃ６を用いた以外は、電池Ａ１のハーフセルと同様にして、電池ＡＣ２のハーフセルを作製した。 (Battery AC2)
A half cell of the battery AC2 was produced in the same manner as the half cell of the battery A1, except that the battery C6 was used.
（評価例２３：作用極Ａｌでのサイクリックボルタンメトリー評価）
　電池Ａ１～電池Ａ４及び電池ＡＣ１のハーフセルに対して、３．１Ｖ～４．６Ｖ、１ｍＶ／ｓの条件で５サイクルのサイクリックボルタンメトリー評価を行い、その後、３．１Ｖ～５．１Ｖ、１ｍＶ／ｓの条件で５サイクルのサイクリックボルタンメトリー評価を行った。電池Ａ１～電池Ａ４及び電池ＡＣ１のハーフセルに対する電位と応答電流との関係を示すグラフを図６５～図７３に示す。 (Evaluation Example 23: Cyclic voltammetry evaluation with working electrode Al)
Cyclic voltammetry was evaluated for 5 cycles under conditions of 3.1 V to 4.6 V and 1 mV / s on the half cells of the batteries A1 to A4 and the battery AC1, and then 3.1 V to 5.1 V, 1 mV / s. Cyclic voltammetry was evaluated for 5 cycles under the conditions of s. 65 to 73 show graphs showing the relationship between the potential and the response current with respect to the half cells of the batteries A1 to A4 and the battery AC1.
　また、電池Ａ２、電池Ａ５及び電池ＡＣ２のハーフセルに対して、３．０Ｖ～４．５Ｖ、１ｍＶ／ｓの条件で、１０サイクルのサイクリックボルタンメトリー評価を行い、その後、３．０Ｖ～５．０Ｖ、１ｍＶ／ｓの条件で、１０サイクルのサイクリックボルタンメトリー評価を行った。電池Ａ２、電池Ａ５及び電池ＡＣ２のハーフセルに対する電位と応答電流との関係を示すグラフを図７４～図７９に示す。 In addition, for the half cells of the battery A2, the battery A5, and the battery AC2, 10 cycles of cyclic voltammetry evaluation was performed under the conditions of 3.0 V to 4.5 V and 1 mV / s, and then, 3.0 V to 5.0 V. The cyclic voltammetry evaluation of 10 cycles was performed under the condition of 1 mV / s. 74 to 79 are graphs showing the relationship between the potential and the response current with respect to the half cells of the battery A2, the battery A5, and the battery AC2.
　図７３から、電池ＡＣ１のハーフセルでは、２サイクル以降も３．１Ｖから４．６Ｖにかけて電流が流れ、高電位になるに従い電流が増大しているのがわかる。また、図７８及び図７９から、電池ＡＣ２のハーフセルにおいても同様に、２サイクル以降も３．０Ｖから４．５Ｖにかけて電流が流れ、高電位になるに従い電流が増大している。この電流は、作用極のアルミニウムが腐食したことによるＡｌの酸化電流と推定される。 FIG. 73 shows that in the half cell of the battery AC1, the current flows from 3.1 V to 4.6 V after the second cycle, and the current increases as the potential increases. Also, from FIGS. 78 and 79, in the half cell of the battery AC2, similarly, the current flows from 3.0 V to 4.5 V after the second cycle, and the current increases as the potential increases. This current is presumed to be the oxidation current of Al due to the corrosion of the working electrode aluminum.
　他方、図６５～図７２から、電池Ａ１～電池Ａ４のハーフセルでは２サイクル以降は３．１Ｖから４．６Ｖにかけてほとんど電流が流れていないことがわかる。４．３Ｖ以上では電位上昇に伴いわずかに電流の増大が観察されるものの、サイクルを繰り返すに従い、電流の量は減少し、定常状態に向かった。特に、電池Ａ１～電池Ａ４のハーフセルは、高電位である５．１Ｖまで電流の顕著な増大が観察されず、しかも、サイクルの繰り返しに伴い電流量の減少が観察された。 On the other hand, it can be seen from FIGS. 65 to 72 that in the half cells of the batteries A1 to A4, almost no current flows from 3.1 V to 4.6 V after two cycles. Although a slight increase in current was observed as the potential increased at 4.3 V or higher, the amount of current decreased as the cycle was repeated, and the steady state was reached. In particular, in the half cells of the batteries A1 to A4, no significant increase in current was observed up to a high potential of 5.1 V, and a decrease in the amount of current was observed as the cycle was repeated.
　また、図７４～図７７から、電池Ａ２及び電池Ａ５のハーフセルにおいても同様に、２サイクル以降は３．０Ｖから４．５Ｖにかけてほとんど電流が流れていないことがわかる。特に３サイクル目以降では４．５Ｖに至るまで電流の増大はほぼない。そして、電池Ａ５のハーフセルでは高電位となる４．５Ｖ以降に電流の増大がみられるが、これは電池ＡＣ２のハーフセルにおける４．５Ｖ以降の電流値に比べると遙かに小さい値である。電池Ａ２のハーフセルについては、４．５Ｖ以降も５．０Ｖに至るまで電流の増大はほぼなく、サイクルの繰り返しに伴い電流量の減少が観察された。 Also, from FIGS. 74 to 77, it can be seen that in the half cells of the battery A2 and the battery A5, almost no current flows from 3.0V to 4.5V after the second cycle. In particular, after the third cycle, there is almost no increase in current up to 4.5V. In the half cell of the battery A5, an increase in current is observed after 4.5 V, which is a high potential, which is much smaller than the current value after 4.5 V in the half cell of the battery AC2. For the half cell of battery A2, there was almost no increase in current until 4.5V after 4.5V, and a decrease in the amount of current was observed as the cycle was repeated.
　サイクリックボルタンメトリー評価の結果から、５Ｖを超える高電位条件でも、電解液Ｅ８、電解液Ｅ１１、電解液Ｅ１６及び電解液Ｅ１９の各電解液のアルミニウムに対する腐食性は低いといえる。すなわち、電解液Ｅ８、電解液Ｅ１１、電解液Ｅ１６及び電解液Ｅ１９の各電解液は、集電体などにアルミニウムを用いた電池に対し、好適な電解液といえる。 From the results of cyclic voltammetry evaluation, it can be said that the corrosiveness of each of the electrolytic solutions E8, E11, E16, and E19 to aluminum is low even under high potential conditions exceeding 5V. That is, each of the electrolytic solution E8, the electrolytic solution E11, the electrolytic solution E16, and the electrolytic solution E19 can be said to be a preferable electrolytic solution for a battery using aluminum as a current collector.
　本発明の電解液として、以下の電解液を具体的に挙げる。なお、以下の電解液には、既述のものも含まれている。 Specific examples of the electrolytic solution of the present invention include the following electrolytic solutions. The following electrolytes include those already described.
（電解液Ａ）
　本発明の電解液を以下のとおり製造した。
　有機溶媒である１，２－ジメトキシエタン約５ｍＬを、撹拌子及び温度計を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中の１，２－ジメトキシエタンに対し、リチウム塩である（ＣＦ３ＳＯ２）２ＮＬｉを溶液温度が４０℃以下を保つように徐々に加え、溶解させた。約１３ｇの（ＣＦ３ＳＯ２）２ＮＬｉを加えた時点で（ＣＦ３ＳＯ２）２ＮＬｉの溶解が一時停滞したので、上記フラスコを恒温槽に投入し、フラスコ内の溶液温度が５０℃となるよう加温し、（ＣＦ３ＳＯ２）２ＮＬｉを溶解させた。約１５ｇの（ＣＦ３ＳＯ２）２ＮＬｉを加えた時点で（ＣＦ３ＳＯ２）２ＮＬｉの溶解が再び停滞したので、１，２－ジメトキシエタンをピペットで１滴加えたところ、（ＣＦ３ＳＯ２）２ＮＬｉは溶解した。さらに（ＣＦ３ＳＯ２）２ＮＬｉを徐々に加え、所定の（ＣＦ３ＳＯ２）２ＮＬｉを全量加えた。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまで１，２－ジメトキシエタンを加えた。得られた電解液は容積２０ｍＬであり、この電解液に含まれる（ＣＦ３ＳＯ２）２ＮＬｉは１８．３８ｇであった。これを電解液Ａとした。電解液Ａにおける（ＣＦ３ＳＯ２）２ＮＬｉの濃度は３．２ｍｏｌ／Ｌであり、密度は１．３９ｇ／ｃｍ３であった。密度は２０℃で測定した。
　なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。 (Electrolytic solution A)
The electrolytic solution of the present invention was produced as follows.
About 5 mL of 1,2-dimethoxyethane, which is an organic solvent, was placed in a flask equipped with a stir bar and a thermometer. Under stirring conditions, (CF 3 SO 2 ) 2 NLi, which is a lithium salt, was gradually added to 1,2-dimethoxyethane in the flask so as to keep the solution temperature at 40 ° C. or lower and dissolved. When about 13 g of (CF 3 SO 2 ) 2 NLi was added, the dissolution of (CF 3 SO 2 ) 2 NLi temporarily stagnated. Therefore, the flask was put into a thermostat, and the solution temperature in the flask was 50 ° C. (CF 3 SO 2 ) 2 NLi was dissolved. When about 15 g of (CF 3 SO 2 ) 2 NLi was added, the dissolution of (CF 3 SO 2 ) 2 NLi stagnated again, so 1 drop of 1,2-dimethoxyethane was added with a pipette (CF 3 SO 2 ) 2 NLi dissolved. Further, (CF 3 SO 2 ) 2 NLi was gradually added, and the entire amount of predetermined (CF 3 SO 2 ) 2 NLi was added. The resulting electrolyte was transferred to a 20 mL volumetric flask and 1,2-dimethoxyethane was added until the volume was 20 mL. The obtained electrolytic solution had a volume of 20 mL, and (CF 3 SO 2 ) 2 NLi contained in this electrolytic solution was 18.38 g. This was designated as an electrolytic solution A. The concentration of (CF 3 SO 2 ) 2 NLi in the electrolytic solution A was 3.2 mol / L, and the density was 1.39 g / cm 3 . The density was measured at 20 ° C.
The production was performed in a glove box under an inert gas atmosphere.
（電解液Ｂ）
　電解液Ａと同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が２．８ｍｏｌ／Ｌであり、密度が１．３６ｇ／ｃｍ３である、電解液Ｂを製造した。 (Electrolytic solution B)
By a method similar to that for the electrolytic solution A, an electrolytic solution B having a (CF 3 SO 2 ) 2 NLi concentration of 2.8 mol / L and a density of 1.36 g / cm 3 was produced.
（電解液Ｃ）
　有機溶媒であるアセトニトリル約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のアセトニトリルに対し、リチウム塩である（ＣＦ３ＳＯ２）２ＮＬｉを徐々に加え、溶解させた。所定の（ＣＦ３ＳＯ２）２ＮＬｉを加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでアセトニトリルを加えた。これを電解液Ｃとした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。 (Electrolytic solution C)
About 5 mL of acetonitrile, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (CF 3 SO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in acetonitrile in the flask. The mixture was stirred overnight when the prescribed (CF 3 SO 2 ) 2 NLi was added. The resulting electrolyte was transferred to a 20 mL volumetric flask and acetonitrile was added until the volume was 20 mL. This was designated as an electrolytic solution C. The production was performed in a glove box under an inert gas atmosphere.
　電解液Ｃは、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が４．２ｍｏｌ／Ｌであり、密度が１．５２ｇ／ｃｍ３であった。 The electrolytic solution C had a (CF 3 SO 2 ) 2 NLi concentration of 4.2 mol / L and a density of 1.52 g / cm 3 .
（電解液Ｄ）
　電解液Ｃと同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が３．０ｍｏｌ／Ｌであり、密度が１．３１ｇ／ｃｍ３である、電解液Ｄを製造した。 (Electrolyte D)
By a method similar to that of the electrolytic solution C, an electrolytic solution D having a concentration of (CF 3 SO 2 ) 2 NLi of 3.0 mol / L and a density of 1.31 g / cm 3 was produced.
（電解液Ｅ）
　有機溶媒としてスルホランを用いた以外は、電解液Ｃと同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が３．０ｍｏｌ／Ｌであり、密度が１．５７ｇ／ｃｍ３である、電解液Ｅを製造した。 (Electrolyte E)
Except for using sulfolane as the organic solvent, in the same manner as the electrolytic solution C, the concentration of (CF 3 SO 2 ) 2 NLi is 3.0 mol / L and the density is 1.57 g / cm 3. Liquid E was produced.
（電解液Ｆ）
　有機溶媒としてジメチルスルホキシドを用いた以外は、電解液Ｃと同様の方法で、（ＣＦ３ＳＯ２）２ＮＬｉの濃度が３．２ｍｏｌ／Ｌであり、密度が１．４９ｇ／ｃｍ３である、電解液Ｆを製造した。 (Electrolyte F)
The concentration of (CF 3 SO 2 ) 2 NLi is 3.2 mol / L and the density is 1.49 g / cm 3 except that dimethyl sulfoxide is used as the organic solvent. Electrolytic solution F was produced.
（電解液Ｇ）
　リチウム塩として（ＦＳＯ２）２ＮＬｉを用い、有機溶媒として１，２－ジメトキシエタンを用いた以外は、電解液Ｃと同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が４．０ｍｏｌ／Ｌであり、密度が１．３３ｇ／ｃｍ３である、電解液Ｇを製造した。 (Electrolyte G)
The concentration of (FSO 2 ) 2 NLi is 4.0 mol / L in the same manner as in the electrolytic solution C, except that (FSO 2 ) 2 NLi is used as the lithium salt and 1,2-dimethoxyethane is used as the organic solvent. An electrolyte solution G having a density of 1.33 g / cm 3 was produced.
（電解液Ｈ）
　電解液Ｇと同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が３．６ｍｏｌ／Ｌであり、密度が１．２９ｇ／ｃｍ３である、電解液Ｈを製造した。 (Electrolyte H)
In the same manner as the electrolytic solution G, an electrolytic solution H having a concentration of (FSO 2 ) 2 NLi of 3.6 mol / L and a density of 1.29 g / cm 3 was produced.
（電解液Ｉ）
　電解液Ｇと同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が２．４ｍｏｌ／Ｌであり、密度が１．１８ｇ／ｃｍ３である、電解液Ｉを製造した。 (Electrolyte I)
In the same manner as the electrolytic solution G, an electrolytic solution I having a concentration of (FSO 2 ) 2 NLi of 2.4 mol / L and a density of 1.18 g / cm 3 was produced.
（電解液Ｊ）
　有機溶媒としてアセトニトリルを用いた以外は、電解液Ｇと同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が５．０ｍｏｌ／Ｌであり、密度が１．４０ｇ／ｃｍ３である、電解液Ｊを製造した。 (Electrolytic solution J)
Except that acetonitrile was used as the organic solvent, an electrolytic solution J having a concentration of (FSO 2 ) 2 NLi of 5.0 mol / L and a density of 1.40 g / cm 3 in the same manner as the electrolytic solution G Manufactured.
（電解液Ｋ）
　電解液Ｊと同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が４．５ｍｏｌ／Ｌであり、密度が１．３４ｇ／ｃｍ３である、電解液Ｋを製造した。 (Electrolytic solution K)
In the same manner as the electrolytic solution J, an electrolytic solution K having a concentration of (FSO 2 ) 2 NLi of 4.5 mol / L and a density of 1.34 g / cm 3 was produced.
（電解液Ｌ）
　有機溶媒であるジメチルカーボネート約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のジメチルカーボネートに対し、リチウム塩である（ＦＳＯ２）２ＮＬｉを徐々に加え、溶解させた。（ＦＳＯ２）２ＮＬｉを全量で１４．６４ｇ加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでジメチルカーボネートを加えた。これを電解液Ｌとした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。
　電解液Ｌにおける（ＦＳＯ２）２ＮＬｉの濃度は３．９ｍｏｌ／Ｌであり、電解液Ｌの密度は１．４４ｇ／ｃｍ３であった。 (Electrolytic solution L)
About 5 mL of dimethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to dimethyl carbonate in the flask and dissolved. When (FSO 2 ) 2 NLi was added in a total amount of 14.64 g, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and dimethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution L. The production was performed in a glove box under an inert gas atmosphere.
The concentration of (FSO 2 ) 2 NLi in the electrolytic solution L was 3.9 mol / L, and the density of the electrolytic solution L was 1.44 g / cm 3 .
（電解液Ｍ）
　電解液Ｌと同様の方法で、（ＦＳＯ２）２ＮＬｉの濃度が２．９ｍｏｌ／Ｌであり、密度が１．３６ｇ／ｃｍ３である、電解液Ｍを製造した。 (Electrolyte M)
In the same manner as the electrolytic solution L, an electrolytic solution M having a (FSO 2 ) 2 NLi concentration of 2.9 mol / L and a density of 1.36 g / cm 3 was produced.
（電解液Ｎ）
　有機溶媒であるエチルメチルカーボネート約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のエチルメチルカーボネートに対し、リチウム塩である（ＦＳＯ２）２ＮＬｉを徐々に加え、溶解させた。（ＦＳＯ２）２ＮＬｉを全量で１２．８１ｇ加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでエチルメチルカーボネートを加えた。これを電解液Ｎとした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。
　電解液Ｎにおける（ＦＳＯ２）２ＮＬｉの濃度は３．４ｍｏｌ／Ｌであり、電解液Ｎの密度は１．３５ｇ／ｃｍ３であった。 (Electrolytic solution N)
About 5 mL of ethyl methyl carbonate, which is an organic solvent, was placed in a flask equipped with a stir bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in ethyl methyl carbonate in the flask. When 12.81 g of (FSO 2 ) 2 NLi was added in total, the mixture was stirred overnight. The obtained electrolytic solution was transferred to a 20 mL volumetric flask, and ethyl methyl carbonate was added until the volume became 20 mL. This was designated as an electrolytic solution N. The production was performed in a glove box under an inert gas atmosphere.
The concentration of (FSO 2 ) 2 NLi in the electrolytic solution N was 3.4 mol / L, and the density of the electrolytic solution N was 1.35 g / cm 3 .
（電解液Ｏ）
　有機溶媒であるジエチルカーボネート約５ｍＬを、撹拌子を備えたフラスコに入れた。撹拌条件下にて、上記フラスコ中のジエチルカーボネートに対し、リチウム塩である（ＦＳＯ２）２ＮＬｉを徐々に加え、溶解させた。（ＦＳＯ２）２ＮＬｉを全量で１１．３７ｇ加えたところで一晩撹拌した。得られた電解液を２０ｍＬメスフラスコに移し、容積が２０ｍＬとなるまでジエチルカーボネートを加えた。これを電解液Ｏとした。なお、上記製造は不活性ガス雰囲気下のグローブボックス内で行った。
　電解液Ｏにおける（ＦＳＯ２）２ＮＬｉの濃度は３．０ｍｏｌ／Ｌであり、電解液Ｏの密度は１．２９ｇ／ｃｍ３であった。 (Electrolytic solution O)
About 5 mL of diethyl carbonate, which is an organic solvent, was placed in a flask equipped with a stirring bar. Under stirring conditions, (FSO 2 ) 2 NLi, which is a lithium salt, was gradually added to and dissolved in diethyl carbonate in the flask. When 11.37 g of the total amount of (FSO 2 ) 2 NLi was added, the mixture was stirred overnight. The resulting electrolyte was transferred to a 20 mL volumetric flask and diethyl carbonate was added until the volume was 20 mL. This was designated as an electrolytic solution O. The production was performed in a glove box under an inert gas atmosphere.
The concentration of (FSO 2 ) 2 NLi in the electrolytic solution O was 3.0 mol / L, and the density of the electrolytic solution O was 1.29 g / cm 3 .
　表３３に上記電解液の一覧を示す。 Table 33 shows a list of the above electrolytes.
Figure JPOXMLDOC01-appb-T000033
Figure JPOXMLDOC01-appb-T000033
（実施例Ｂ－１）
　正極（作用極）と電解液とを有するハーフセルを作製し、これについてサイクリックボルタンメトリー（ＣＶ）評価を行った。 Example B-1
A half cell having a positive electrode (working electrode) and an electrolytic solution was prepared and subjected to cyclic voltammetry (CV) evaluation.
　正極は、正極活物質層と、正極活物質層で被覆された集電体とからなる。正極活物質層は、正極活物質と、結着剤と、導電助剤とを有する。正極活物質は、ＬｉＭｎ２Ｏ４からなる。結着剤は、ポリフッ化ビニリデン（ＰＶＤＦ）からなる。導電助剤は、アセチレンブラック（ＡＢ）からなる。集電体は、厚み２０μｍのアルミニウム箔からなる。正極活物質層を１００質量部としたときの、正極活物質と結着剤と導電助剤との含有質量比は、９４：３：３である。 The positive electrode includes a positive electrode active material layer and a current collector covered with the positive electrode active material layer. The positive electrode active material layer has a positive electrode active material, a binder, and a conductive additive. The positive electrode active material is made of LiMn 2 O 4 . The binder is made of polyvinylidene fluoride (PVDF). The conductive auxiliary agent is made of acetylene black (AB). The current collector is made of an aluminum foil having a thickness of 20 μm. When the positive electrode active material layer is 100 parts by mass, the mass ratio of the positive electrode active material, the binder, and the conductive additive is 94: 3: 3.
　正極を作製するために、ＬｉＭｎ２Ｏ４、ＰＶＤＦ及びＡＢを上記の質量比となるように混合し、溶剤としてのＮ－メチル－２－ピロリドン（ＮＭＰ）を添加してペースト状の正極材とする。ペースト状の正極材を、集電体の表面にドクターブレードを用いて塗布して、正極活物質層を形成した。正極活物質層を、８０℃で２０分間乾燥することで、ＮＭＰを揮発により除去した。表面に正極活物質層を形成したアルミニウム箔を、ロ－ルプレス機を用いて圧縮し、アルミニウム箔と正極活物質層とを強固に密着接合させた。接合物を１２０℃で６時間、真空乾燥機で加熱し、所定の形状に切り取り、正極を得た。 In order to produce a positive electrode, LiMn 2 O 4 , PVDF and AB are mixed so as to have the above mass ratio, and N-methyl-2-pyrrolidone (NMP) as a solvent is added to form a paste-like positive electrode material and To do. The paste-like positive electrode material was applied to the surface of the current collector using a doctor blade to form a positive electrode active material layer. The positive electrode active material layer was dried at 80 ° C. for 20 minutes to remove NMP by volatilization. The aluminum foil having the positive electrode active material layer formed on the surface thereof was compressed using a roll press, and the aluminum foil and the positive electrode active material layer were firmly bonded. The joined product was heated in a vacuum dryer at 120 ° C. for 6 hours, cut into a predetermined shape, and a positive electrode was obtained.
　実施例Ｂ－１の電解液として、上記の電解液Ｅ８を用いた。 The above electrolytic solution E8 was used as the electrolytic solution of Example B-1.
　上記の正極（作用極）及び電解液を用いて、ハーフセルを製作した。対極は、金属リチウムからなる。セパレータは、ガラスフィルター不織布からなる。 A half cell was manufactured using the positive electrode (working electrode) and the electrolytic solution. The counter electrode is made of metallic lithium. The separator is made of a glass filter nonwoven fabric.
（実施例Ｂ－２）
　実施例Ｂ－２の電解液として、上記の電解液Ｅ４を用いた。実施例Ｂ－２のハーフセルのその他の点は、実施例Ｂ－１と同様である。 Example B-2
The electrolyte solution E4 described above was used as the electrolyte solution of Example B-2. Other points of the half cell of Example B-2 are the same as those of Example B-1.
（実施例Ｂ－３）
　実施例Ｂ－３の電解液として、上記の電解液Ｅ１１を用いた。実施例Ｂ－３のハーフセルのその他の点は、実施例Ｂ－１と同様である。 Example B-3
The electrolyte solution E11 described above was used as the electrolyte solution of Example B-3. Other points of the half cell of Example B-3 are the same as those of Example B-1.
（比較例Ｂ－１）
　比較例Ｂ－１の電解液として、上記の電解液Ｃ５を用いた。実施例Ｂ－３のハーフセルのその他の点は、実施例Ｂ－１と同様である。 (Comparative Example B-1)
The above electrolyte C5 was used as the electrolyte of Comparative Example B-1. Other points of the half cell of Example B-3 are the same as those of Example B-1.
（評価例Ｂ－１：ＣＶ評価）
　実施例Ｂ－１のハーフセルについて、サイクリックボルタンメトリ－（ＣＶ）評価試験を行った。評価条件は、掃引速度０．１ｍＶ／ｓ、掃引範囲３．１Ｖ～４．６Ｖ（ｖｓ　Ｌｉ）とし、充電、放電を２サイクル繰り返した。 (Evaluation Example B-1: CV Evaluation)
The half cell of Example B-1 was subjected to a cyclic voltammetry (CV) evaluation test. The evaluation conditions were a sweep rate of 0.1 mV / s and a sweep range of 3.1 V to 4.6 V (vs Li), and charging and discharging were repeated for two cycles.
　ＣＶの測定の結果を図８０に示した。横軸は、作用極の電位（ｖｓ．Ｌｉ／Ｌｉ＋）を示し、縦軸は、酸化還元により発生する電流を示す。図８０に示すように、４．４Ｖ付近に酸化ピーク、３．８Ｖ付近に還元ピークを確認し、可逆的な電気化学反応が起こっていることがわかった。このことから、上記の正極と電解液とを備えた非水系二次電池において、可逆的に電気化学反応が起こることがわかった。 The results of CV measurement are shown in FIG. The horizontal axis represents the potential of the working electrode (vs. Li / Li + ), and the vertical axis represents the current generated by redox. As shown in FIG. 80, an oxidation peak was observed near 4.4V, and a reduction peak was observed near 3.8V, indicating that a reversible electrochemical reaction occurred. From this, it was found that an electrochemical reaction occurs reversibly in the non-aqueous secondary battery including the positive electrode and the electrolytic solution.
（評価例Ｂ－２：充放電特性）
　実施例Ｂ－１，実施例Ｂ－２，実施例Ｂ－３及び比較例Ｂ－１のハーフセルについて、３Ｖ～４．４Ｖ、０．１Ｃ（１Ｃは、一定電流において１時間で電池を完全充電、または放電させるために要する電流値を示す。）でＣＣ充放電を行い、充放電曲線を作成した。測定結果を図８１に示す。 (Evaluation Example B-2: Charge / Discharge Characteristics)
For the half cells of Example B-1, Example B-2, Example B-3 and Comparative Example B-1, 3V to 4.4V, 0.1C (1C is a fully charged battery in one hour at a constant current) , Or the current value required for discharging).) CC charge / discharge was performed to create a charge / discharge curve. The measurement results are shown in FIG.
　このことから、本発明の電解液を用いた実施例Ｂ－１，Ｂ－２のハーフセルは、一般的な電解液を用いた比較例Ｂ－１と遜色ない充放電容量が得られることがわかった。更に、実施例Ｂ－３は、実施例Ｂ－１，実施例Ｂ－２及び比較例Ｂ－１に比べて充電容量及び放電容量が大きかった。このため、実施例Ｂ－３は、可逆容量が増加した。その理由は定かではないが、鎖状カーボネート系高濃度電解液では初回不可逆容量の低減によって利用可能な容量が増えていると推測される。 From this, it can be seen that the half cells of Examples B-1 and B-2 using the electrolytic solution of the present invention can obtain a charge / discharge capacity comparable to that of Comparative Example B-1 using a general electrolytic solution. It was. Further, Example B-3 had larger charge capacity and discharge capacity than Examples B-1, Example B-2, and Comparative Example B-1. For this reason, the reversible capacity of Example B-3 increased. The reason is not clear, but it is presumed that the usable capacity of the chain carbonate-based high-concentration electrolytic solution is increased by reducing the initial irreversible capacity.
（実施例Ｃ－１）
　実施例Ｃ－１は、作用極（正極）と対極（負極）と電解液とを備えるハーフセルである。 Example C-1
Example C-1 is a half cell including a working electrode (positive electrode), a counter electrode (negative electrode), and an electrolytic solution.
　作用極としての正極は、正極活物質層と、正極活物質層で被覆された集電体とからなる。正極活物質層は、正極活物質と、結着剤と、導電助剤とを有する。正極活物質は導電性炭素を１０％とオリビン構造をもつＬｉＦｅＰＯ４からなる。結着剤は、ポリフッ化ビニリデン（ＰＶＤＦ）からなる。導電助剤は、アセチレンブラック（ＡＢ）からなる。集電体は、厚み２０μｍのアルミニウム箔からなる。正極活物質層を１００質量部としたときの、正極活物質と結着剤と導電助剤との含有質量比は、９０：５：５である。 The positive electrode as the working electrode includes a positive electrode active material layer and a current collector covered with the positive electrode active material layer. The positive electrode active material layer has a positive electrode active material, a binder, and a conductive additive. The positive electrode active material is made of LiFePO 4 having 10% conductive carbon and an olivine structure. The binder is made of polyvinylidene fluoride (PVDF). The conductive auxiliary agent is made of acetylene black (AB). The current collector is made of an aluminum foil having a thickness of 20 μm. When the positive electrode active material layer is 100 parts by mass, the mass ratio of the positive electrode active material, the binder, and the conductive additive is 90: 5: 5.
　正極を作製するために、ＬｉＦｅＰＯ４、ＰＶＤＦ及びＡＢを上記の質量比となるように混合し、溶剤としてのＮ－メチル－２－ピロリドン（ＮＭＰ）を添加してペースト状の正極材とする。ペースト状の正極材を、集電体の表面にドクターブレードを用いて塗布して、正極活物質層を形成した。正極活物質層を、８０℃で２０分間乾燥することで、ＮＭＰを揮発により除去した。表面に正極活物質層を形成したアルミニウム箔を、ロ－ルプレス機を用いて圧縮し、アルミニウム箔と正極活物質層とを強固に密着接合させた。接合物を１２０℃で６時間、真空乾燥機で加熱し、所定の形状に切り取り、正極を得た。 In order to produce a positive electrode, LiFePO 4 , PVDF and AB are mixed so as to have the above mass ratio, and N-methyl-2-pyrrolidone (NMP) as a solvent is added to obtain a paste-like positive electrode material. The paste-like positive electrode material was applied to the surface of the current collector using a doctor blade to form a positive electrode active material layer. The positive electrode active material layer was dried at 80 ° C. for 20 minutes to remove NMP by volatilization. The aluminum foil having the positive electrode active material layer formed on the surface thereof was compressed using a roll press, and the aluminum foil and the positive electrode active material layer were firmly bonded. The joined product was heated in a vacuum dryer at 120 ° C. for 6 hours, cut into a predetermined shape, and a positive electrode was obtained.
　実施例Ｃ－１の電解液として、上記の電解液Ｅ８を用いた。 The above electrolytic solution E8 was used as the electrolytic solution of Example C-1.
　上記の正極（作用極）及び電解液を用いて、ハーフセルを製作した。対極は、金属リチウムからなる。セパレータは、ガラスフィルター（ＧＥヘルスケア・ジャパン株式会社、厚さ４００μｍ）からなる。 A half cell was manufactured using the positive electrode (working electrode) and the electrolytic solution. The counter electrode is made of metallic lithium. The separator is made of a glass filter (GE Healthcare Japan, Inc., thickness 400 μm).
（実施例Ｃ－２）
　実施例Ｃ－２のハーフセルは、電解液として、上記の電解液Ｅ１１を用いている。その他の構成は、実施例Ｃ－１と同様である。 Example C-2
The half cell of Example C-2 uses the above-described electrolytic solution E11 as the electrolytic solution. The other configuration is the same as that of Example C-1.
（実施例Ｃ－３）
　実施例Ｃ－３のハーフセルは、電解液として、上記の電解液Ｅ１３を用いている。その他の構成は、実施例Ｃ－１と同様である。 Example C-3
The half cell of Example C-3 uses the above-described electrolytic solution E13 as the electrolytic solution. The other configuration is the same as that of Example C-1.
（比較例Ｃ－１）
　比較例Ｃ－１のハーフセルは、電解液として、上記の電解液Ｃ５を用いている。その他の構成は、実施例Ｃ－１と同様である。 (Comparative Example C-1)
The half cell of Comparative Example C-1 uses the above electrolytic solution C5 as the electrolytic solution. The other configuration is the same as that of Example C-1.
（比較例Ｃ－２）
　比較例Ｃ－２のハーフセルは、電解液として、上記の電解液Ｃ６を用いている。その他の構成は、実施例Ｃ－１と同様である。 (Comparative Example C-2)
The half cell of Comparative Example C-2 uses the above electrolytic solution C6 as the electrolytic solution. The other configuration is the same as that of Example C-1.
（評価例Ｃ－１：レート容量評価１）
　実施例Ｃ－１及び比較例Ｃ－１のハーフセルに対し、０．１Ｃ（１Ｃとは一定電流において１時間で電池を完全充電、または放電させるために要する電流値を示す。）レートで４．２Ｖ（ｖｓ　Ｌｉ）まで定電流充電を行った後に、０．１Ｃ、１Ｃ、５Ｃ、１０Ｃレートで２Ｖまで放電を行い、それぞれのレートにおける容量（放電容量）を測定した。実施例Ｃ－１及び比較例Ｃ－１について、各レートでの放電曲線を図８２、図８３に示した。０．１Ｃ放電容量に対する５Ｃ及び１０Ｃでの放電容量の割合（レート容量特性）を算出した。結果を表３４に示す。 (Evaluation Example C-1: Rate Capacity Evaluation 1)
The half cell of Example C-1 and Comparative Example C-1 has a rate of 0.1 C (1 C represents a current value required to fully charge or discharge the battery in one hour at a constant current). After carrying out constant current charge to 2V (vs Li), it discharged to 2V at a 0.1C, 1C, 5C, 10C rate, and measured the capacity | capacitance (discharge capacity) in each rate. For Example C-1 and Comparative Example C-1, discharge curves at various rates are shown in FIGS. The ratio (rate capacity characteristics) of the discharge capacity at 5C and 10C with respect to the 0.1C discharge capacity was calculated. The results are shown in Table 34.
Figure JPOXMLDOC01-appb-T000034
Figure JPOXMLDOC01-appb-T000034
　図８２、図８３、及び表３４に示すように、本発明の実施例Ｃ－１のハーフセルは、比較例Ｃ－１のハーフセルに比べて、レートを高くしたときの容量の低下が抑制されており、優れたレート容量特性を示した。本発明の電解液を使用した二次電池は、優れたレート容量特性を示すことがわかった。 As shown in FIG. 82, FIG. 83, and Table 34, the half cell of Example C-1 of the present invention has a reduced capacity drop when the rate is increased compared to the half cell of Comparative Example C-1. It showed excellent rate capacity characteristics. It was found that the secondary battery using the electrolytic solution of the present invention exhibits excellent rate capacity characteristics.
（評価例Ｃ－２：充放電試験）
　実施例Ｃ－２のハーフセルに対して充放電試験を行った。充放電条件は、０．１Ｃ、定電流、２．５Ｖ－４．０Ｖ（vs　Li）である。充電及び放電をそれぞれ５回繰り返した。充放電曲線を図８４に示した。
　図８４に示すように、実施例Ｃ－２のハーフセルにおいて、可逆的に充放電が繰り返されることが確認できた。 (Evaluation Example C-2: Charge / Discharge Test)
A charge / discharge test was performed on the half cell of Example C-2. The charge / discharge conditions are 0.1 C, constant current, 2.5 V-4.0 V (vs Li). Charging and discharging were repeated 5 times each. A charge / discharge curve is shown in FIG.
As shown in FIG. 84, it was confirmed that charging and discharging were reversibly repeated in the half cell of Example C-2.
（評価例Ｃ－３：レート容量評価２）
　実施例Ｃ－２のハーフセルに対し、２．５～４．０Ｖの範囲で定電流で充電及び放電を繰り返した。充電及び放電の各サイクルにおける放電容量を測定した。３サイクル毎に充電及び放電のレートを以下のように変化させた。
　０．１Ｃ、３サイクル→０．２Ｃ、３サイクル→０．５Ｃ、３サイクル→１Ｃ、３サイクル→２Ｃ、３サイクル→５Ｃ、３サイクル→０．１Ｃ、３サイクル
　各サイクル毎の放電レート容量を測定し、図８５に示した。また、この室温レート容量試験において、０．１Ｃ、５Ｃでの３サイクルのうち、それぞれ２サイクル目の放電容量を表３５に示した。 (Evaluation Example C-3: Rate Capacity Evaluation 2)
The half cell of Example C-2 was repeatedly charged and discharged with a constant current in the range of 2.5 to 4.0 V. The discharge capacity in each cycle of charge and discharge was measured. The charge and discharge rates were changed every three cycles as follows.
0.1C, 3 cycles → 0.2C, 3 cycles → 0.5C, 3 cycles → 1C, 3 cycles → 2C, 3 cycles → 5C, 3 cycles → 0.1C, 3 cycles Discharge rate capacity for each cycle Measured and shown in FIG. In addition, in this room temperature rate capacity test, the discharge capacity at the second cycle among the three cycles at 0.1 C and 5 C is shown in Table 35.
Figure JPOXMLDOC01-appb-T000035
Figure JPOXMLDOC01-appb-T000035
　図８５及び表３５に示すように、実施例Ｃ－２，Ｃ－３は、比較例Ｃ－１，Ｃ－２に比べて、放電レート容量が高かった。特に０．５Ｃ～５Ｃレートの際の放電レート容量については、実施例Ｃ－２，Ｃ－３は、比較例Ｃ－１，Ｃ－２に比べて、顕著に高かった。実施例Ｃ－２，Ｃ－３では、実施例Ｃ－２が実施例Ｃ－３に比べてレート容量が高かった。 85 and Table 35, Examples C-2 and C-3 had higher discharge rate capacities than Comparative Examples C-1 and C-2. In particular, the discharge rate capacities at the rates of 0.5 C to 5 C were significantly higher in Examples C-2 and C-3 than in Comparative Examples C-1 and C-2. In Examples C-2 and C-3, the rate capacity of Example C-2 was higher than that of Example C-3.
（評価例Ｃ－４：低温下でのレート容量評価）
　実施例Ｃ－１及び比較例Ｃ－１のハーフセルに対し、－２０℃の環境下で、０．１Ｃレートで４．２Ｖ（ｖｓ　Ｌｉ）まで定電流充電を行った後に、０．０５Ｃ、０．５Ｃレートで２Ｖまで放電を行い、それぞれのレートにおける放電容量及び充電容量を測定した。実施例Ｃ－１のハーフセルの各レートでの充放電曲線を図８６に示し、比較例Ｃ－１のハーフセルの各レートでの充放電曲線を図８７に示した。また、実施例Ｃ－1及び比較例Ｃ－１のハーフセルの０．０５Ｃ、０．５Ｃレートでの放電容量、及び０．０５Ｃでの放電容量に対する０．５Ｃでの放電容量の割合（レート容量特性）を表３６に示した。実施例Ｃ－1及び比較例Ｃ－１のハーフセルの０．０５Ｃ、０．５Ｃレートでの充電容量、及び０．０５Ｃでの充電容量に対する０．５Ｃでの充電容量の割合（レート容量特性）を表３７に示した。 (Evaluation Example C-4: Rate Capacity Evaluation at Low Temperature)
The half cells of Example C-1 and Comparative Example C-1 were subjected to constant current charging at a 0.1 C rate to 4.2 V (vs Li) in an environment of −20 ° C., and then 0.05 C, 0 The battery was discharged at a rate of 5 C to 2 V, and the discharge capacity and the charge capacity at each rate were measured. The charge / discharge curves at the respective rates of the half cell of Example C-1 are shown in FIG. 86, and the charge / discharge curves at the respective rates of the half cell of Comparative Example C-1 are shown in FIG. In addition, the discharge capacity at 0.05 C and 0.5 C rates of the half cells of Example C-1 and Comparative Example C-1, and the ratio of the discharge capacity at 0.5 C to the discharge capacity at 0.05 C (rate capacity) The properties are shown in Table 36. Charge capacity at 0.05C and 0.5C rates of the half cells of Example C-1 and Comparative Example C-1, and ratio of charge capacity at 0.5C to charge capacity at 0.05C (rate capacity characteristics) Is shown in Table 37.
Figure JPOXMLDOC01-appb-T000036
Figure JPOXMLDOC01-appb-T000036
Figure JPOXMLDOC01-appb-T000037
Figure JPOXMLDOC01-appb-T000037
　表３６、表３７に示すように、実施例Ｃ－１は比較例Ｃ－１に比べて、充電、放電共にレート容量特性（０．５Ｃ／０．０５Ｃ容量）が高い。図８６，図８７に示すように、実施例Ｃ－１を比較例Ｃ－１と比べると、比較例Ｃ－１では、例えば、５０ｍＡｈ／g地点における充電カーブの電位（閉回路電位）と放電カーブの電位（閉回路電位）との差が大きく、この差は、特に、１／２Ｃなどの高レート試験時に顕著となっている。これに対して、実施例Ｃ－１では、比較例Ｃ－１に比べて、電位差が極めて小さい。つまり、実施例Ｃ－１は比較例Ｃ－１に対し分極が小さいといえる。 As shown in Tables 36 and 37, Example C-1 has higher rate capacity characteristics (0.5 C / 0.05 C capacity) for both charging and discharging than Comparative Example C-1. As shown in FIGS. 86 and 87, when Example C-1 is compared with Comparative Example C-1, in Comparative Example C-1, for example, the charge curve potential (closed circuit potential) and discharge at a point of 50 mAh / g The difference from the curve potential (closed circuit potential) is large, and this difference is particularly noticeable during high-rate tests such as 1 / 2C. On the other hand, in Example C-1, the potential difference is extremely small compared to Comparative Example C-1. In other words, it can be said that Example C-1 has a smaller polarization than Comparative Example C-1.
（電池Ｄ－１）
　作用極は白金（Ｐｔ）、対極はリチウム金属（Ｌｉ）とした。セパレータは、ガラスフィルター不織布とした。
　上記の電解液Ｅ１、作用極、電解液及びセパレータを用いて、電池Ｄ－１のハーフセルを製作した。 (Battery D-1)
The working electrode was platinum (Pt) and the counter electrode was lithium metal (Li). The separator was a glass filter nonwoven fabric.
Using the electrolytic solution E1, the working electrode, the electrolytic solution, and the separator, a half cell of the battery D-1 was manufactured.
（電池Ｄ－２）
　電解液として電解液Ｅ４を用いた以外は、電池Ｄ－１と同様の方法で、電池Ｄ－２のハーフセルを製造した。 (Battery D-2)
A half cell of battery D-2 was produced in the same manner as battery D-1, except that electrolyte E4 was used as the electrolyte.
（電池Ｄ－３）
　以下の方法で電池Ｄ－３のハーフセルを作製した。
　作用極は、以下のように作成した。
　活物質であるＬｉＮｉ０．５Ｍｎ１．５Ｏ４８９質量部、及び結着剤であるポリフッ化ビニリデン１１質量部を混合した。この混合物を適量のＮ－メチル－２－ピロリドンに分散させて、スラリーを作製した。集電体として厚み２０μｍの銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を乾燥してＮ－メチル－２－ピロリドンを除去し、その後、銅箔をプレスし、接合物を得た。得られた接合物を真空乾燥機で１２０℃、６時間加熱乾燥して、活物質層が形成された銅箔を得た。これを作用極とした。ここで、銅箔１ｃｍ２あたりの活物質の質量は６．３ｍｇであった。
　対極はリチウム金属とした。作用極、対極、ガラスフィルター不織布からなるセパレータ及び電解液Ｅ４を、径１３．８２ｍｍの電池ケース（宝泉株式会社製　ＣＲ２０３２型コインセルケース）に収容しハーフセルを構成した。これを電池Ｄ－３のハーフセルとした。 (Battery D-3)
A half cell of Battery D-3 was produced by the following method.
The working electrode was created as follows.
89 parts by mass of LiNi 0.5 Mn 1.5 O 4 as an active material and 11 parts by mass of polyvinylidene fluoride as a binder were mixed. This mixture was dispersed in an appropriate amount of N-methyl-2-pyrrolidone to prepare a slurry. A copper foil having a thickness of 20 μm was prepared as a current collector. The slurry was applied in a film form on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried to remove N-methyl-2-pyrrolidone, and then the copper foil was pressed to obtain a bonded product. The obtained joined product was heat-dried at 120 ° C. for 6 hours with a vacuum dryer to obtain a copper foil on which an active material layer was formed. This was the working electrode. Here, the mass of the active material per 1 cm 2 of the copper foil was 6.3 mg.
The counter electrode was lithium metal. A separator made of a working electrode, a counter electrode, a glass filter nonwoven fabric, and an electrolytic solution E4 were accommodated in a battery case (CR2032 type coin cell case manufactured by Hosen Co., Ltd.) having a diameter of 13.82 mm to form a half cell. This was designated as a half cell of Battery D-3.
（電池Ｄ－４）
　電解液Ｅ１１を用いた以外は、電池Ｄ－３と同様の方法で、電池Ｄ－４のハーフセルを作製した。 (Battery D-4)
A half cell of the battery D-4 was produced in the same manner as the battery D-3 except that the electrolytic solution E11 was used.
（電池Ｄ－Ｃ１）
　電解液として電解液Ｃ１を用いた以外は、電池Ｄ－１と同様の方法で、電池Ｄ－Ｃ１のハーフセルを製造した。 (Battery D-C1)
A half cell of Battery D-C1 was produced in the same manner as Battery D-1, except that Electrolytic Solution C1 was used as the electrolytic solution.
（電池Ｄ－Ｃ２）
　電解液として、有機溶媒がＤＭＥであり（ＣＦ３ＳＯ２）２ＮＬｉの濃度が０．１ｍｏｌ／Ｌである電解液Ｃ９を用いた以外は、電池Ｄ－１と同様に、電池Ｄ－Ｃ２のハーフセルを製造した。電池Ｄ－Ｃ２の電解液Ｃ９には、（ＣＦ３ＳＯ２）２ＮＬｉ１分子に対し１，２－ジメトキシエタン９３分子が含まれている。 (Battery D-C2)
The battery D-C2 was the same as the battery D-1, except that the electrolyte used was an electrolyte C9 in which the organic solvent was DME and the concentration of (CF 3 SO 2 ) 2 NLi was 0.1 mol / L. Half cell was manufactured. The electrolytic solution C9 of the battery D-C2 contains 93 molecules of 1,2-dimethoxyethane with respect to (CF 3 SO 2 ) 2 NLi1 molecules.
　表３８に各電池に用いた電解液の一覧を示す。 Table 38 shows a list of electrolytes used for each battery.
Figure JPOXMLDOC01-appb-T000038
Figure JPOXMLDOC01-appb-T000038
（評価例Ｄ－１：ＬＳＶ測定）
　電池Ｄ－１、電池Ｄ－２及び電池Ｄ－Ｃ１、電池Ｄ－Ｃ２のハーフセルについて、リニアスイープボルタンメトリー（ＬＳＶ）の測定を行った。測定条件は、電池Ｄ－１及び電池Ｄ－Ｃ１、電池Ｄ－Ｃ２については、掃引速度０．１ｍＶ／ｓ、電池Ｄ－２については掃引速度１ｍＶ／ｓとした。図８８，図８９には、ＬＳＶ測定により形成された電位－電流曲線を示した。図８８は、電池Ｄ－１及び電池Ｄ－Ｃ１、電池Ｄ－Ｃ２の電位－電流曲線を示し、図８９は電池Ｄ－２の電位－電流曲線を示す。図８８の横軸は、Ｌｉ＋／Ｌｉ電極を基準電位とした電位（Ｖ）を示し、縦軸は電流値（ｍＡｃｍ－２）を示す。図８９の横軸は、Ｌｉ＋／Ｌｉ電極を基準電位とした電位（Ｖ）を示し、縦軸は電流値（μＡ）を示す。 (Evaluation example D-1: LSV measurement)
Linear sweep voltammetry (LSV) was measured for the half cells of Battery D-1, Battery D-2, Battery D-C1, and Battery D-C2. The measurement conditions were a sweep rate of 0.1 mV / s for battery D-1, battery D-C1, and battery D-C2, and a sweep rate of 1 mV / s for battery D-2. 88 and 89 show potential-current curves formed by LSV measurement. FIG. 88 shows the potential-current curves of the battery D-1, the battery D-C1, and the battery D-C2, and FIG. 89 shows the potential-current curve of the battery D-2. The horizontal axis in FIG. 88 indicates the potential (V) with the Li + / Li electrode as the reference potential, and the vertical axis indicates the current value (mAcm −2 ). The horizontal axis in FIG. 89 represents the potential (V) with the Li + / Li electrode as the reference potential, and the vertical axis represents the current value (μA).
　図８８に示すように、電池Ｄ－１の電位－電流曲線の立ち上がり部は、比較例１，２の立ち上がり部よりも高い電位の側に位置していた。電池Ｄ－１では、立ち上がり部の開始点は、Ｌｉ／Ｌｉ＋電極を基準電位としたときの電位４．７Ｖに位置し、立ち上がり部は開始点の電位４．７Ｖからそれ以上の電位で示されていた。 As shown in FIG. 88, the rising portion of the potential-current curve of the battery D-1 was located on the higher potential side than the rising portions of Comparative Examples 1 and 2. In battery D-1, the starting point of the rising portion is located at a potential of 4.7 V when the Li / Li + electrode is used as a reference potential, and the rising portion is indicated by a potential higher than the starting point potential of 4.7 V. It had been.
　電池Ｄ－２では、立ち上がり部の開始点は、Ｌｉ／Ｌｉ＋電極を基準電位としたときの電位５．７Ｖに位置し、立ち上がり部は開始点の電位５．７Ｖからそれ以上の電位で示されていた。以上より、電池Ｄ－１の電解液は、酸化反応が生じる酸化分解電位が４．５Ｖ以上であり、電池Ｄ－２では５Ｖ以上であることがわかった。 In battery D-2, the starting point of the rising portion is located at a potential of 5.7 V when the Li / Li + electrode is used as a reference potential, and the rising portion is indicated by a potential higher than the starting point potential of 5.7 V. It had been. From the above, it was found that the electrolytic solution of the battery D-1 has an oxidative decomposition potential at which an oxidation reaction occurs is 4.5 V or more, and the battery D-2 has 5 V or more.
　電池Ｄ－１、電池Ｄ－２、及び電池Ｄ－Ｃ１では、電流の増加量を電位の増加量で２階微分した値をＢとしたとき、電流－電位曲線での電圧印加直後から立ち上がり部までの間の領域において、Ｂ≧０の関係をもっていた。 In the battery D-1, the battery D-2, and the battery D-C1, when the value obtained by second-order differentiation of the increase amount of the current with the increase amount of the potential is B, the rising portion immediately after the voltage application in the current-potential curve In the region up to, there was a relationship of B ≧ 0.
　電池Ｄ－Ｃ１では、立ち上がり部の開始点は、４．２Ｖであった。電池Ｄ－Ｃ２では４．２Ｖであった。電池Ｄ－Ｃ２では、電位４．５～４．６Ｖ（ｖｓ　Ｌｉ＋／Ｌｉ）近傍でＢ＜０の関係をもっていた。通常の二次電池は、満充電時に生じる電圧の急激な降下を検知する検知手段と、急激な電圧降下が生じたときに充電を停止させる終止手段を備えている。電池Ｄ－Ｃ２の電解液Ｃ９を用いて作成したリチウムイオン二次電池は、電圧印加開始から立ち上がり部までの充電時に、検知手段によって過剰充電に見られる急激な電圧降下と誤って判断され、終止手段により充電が停止されるおそれがある。 In battery D-C1, the starting point of the rising portion was 4.2V. In Battery D-C2, it was 4.2V. The battery D-C2 had a relationship of B <0 in the vicinity of the potential 4.5 to 4.6 V (vs Li + / Li). A normal secondary battery includes a detection unit that detects a sudden drop in voltage that occurs during full charge and a termination unit that stops charging when a sudden voltage drop occurs. Lithium ion secondary battery prepared using electrolyte C9 of battery D-C2 is erroneously determined to be a sudden voltage drop seen by overcharging by the detecting means during charging from the start of voltage application to the rising part, and is terminated. The charging may be stopped by the means.
（評価例Ｄ－２：充放電特性）
　電池Ｄ－３のハーフセルについて、３Ｖ～４．８Ｖ、０．１Ｃ（１Ｃは、一定電流において１時間で電池を完全充電、または放電させるために要する電流値を示す。）でＣＣ充放電を行い、充放電曲線を作成した。電池Ｄ－３の測定結果を図９０に示す。また、電池Ｄ－４のハーフセルについて、３．０Ｖ～４．９Ｖ、０．１ＣでＣＣ充放電を行い、充放電曲線を作成した。電池Ｄ－４の測定結果を図９１に示す。 (Evaluation Example D-2: Charge / Discharge Characteristics)
For the half cell of battery D-3, charge / discharge CC at 3V to 4.8V, 0.1C (1C indicates the current value required to fully charge or discharge the battery in 1 hour at a constant current). A charge / discharge curve was created. FIG. 90 shows the measurement result of the battery D-3. Further, with respect to the half cell of Battery D-4, CC charge / discharge was performed at 3.0 V to 4.9 V and 0.1 C to prepare a charge / discharge curve. FIG. 91 shows the measurement result of the battery D-4.
　図９０に示すように、電池Ｄ－３のハーフセルは、４．８Ｖで可逆的に充放電を行うことができた。また、図９１に示すように、電池Ｄ－４のハーフセルは、４．９Ｖで可逆的に充放電を行うことができた。電池Ｄ－４のハーフセルの容量は約１２０ｍＡｈ／ｇであった。 As shown in FIG. 90, the half cell of the battery D-3 was able to charge and discharge reversibly at 4.8V. Further, as shown in FIG. 91, the half cell of the battery D-4 was able to be reversibly charged / discharged at 4.9V. The capacity of the half cell of Battery D-4 was about 120 mAh / g.
（電池Ｄ－５）
　電解液Ｅ８を用いたハーフセルを以下のとおり製造した。 (Battery D-5)
A half cell using the electrolytic solution E8 was produced as follows.
　活物質である平均粒径１０μｍの黒鉛９０質量部、及び結着剤であるポリフッ化ビニリデン１０質量部を混合した。この混合物を適量のＮ－メチル－２－ピロリドンに分散させて、スラリーを作製した。集電体として厚み２０μｍの銅箔を準備した。この銅箔の表面に、ドクターブレードを用いて、上記スラリーを膜状に塗布した。スラリーが塗布された銅箔を乾燥してＮ－メチル－２－ピロリドンを除去し、その後、銅箔をプレスし、接合物を得た。得られた接合物を真空乾燥機で１２０℃、６時間加熱乾燥して、活物質層が形成された銅箔を得た。これを作用極とした。なお、銅箔１ｃｍ２あたりの活物質の質量は１．４８ｍｇであった。また、プレス前の黒鉛及びポリフッ化ビニリデンの密度は０．６８ｇ／ｃｍ３であり、プレス後の活物質層の密度は１．０２５ｇ／ｃｍ３であった。 90 parts by mass of graphite having an average particle diameter of 10 μm as an active material and 10 parts by mass of polyvinylidene fluoride as a binder were mixed. This mixture was dispersed in an appropriate amount of N-methyl-2-pyrrolidone to prepare a slurry. A copper foil having a thickness of 20 μm was prepared as a current collector. The slurry was applied in a film form on the surface of the copper foil using a doctor blade. The copper foil coated with the slurry was dried to remove N-methyl-2-pyrrolidone, and then the copper foil was pressed to obtain a bonded product. The obtained joined product was heat-dried at 120 ° C. for 6 hours with a vacuum dryer to obtain a copper foil on which an active material layer was formed. This was the working electrode. In addition, the mass of the active material per 1 cm 2 of copper foil was 1.48 mg. Further, the density of graphite and polyvinylidene fluoride before pressing was 0.68 g / cm 3 , and the density of the active material layer after pressing was 1.025 g / cm 3 .
　対極は金属Ｌｉとした。 The counter electrode was metal Li.
　作用極、対極、両者の間に挟装したセパレータとしての厚さ４００μｍの Ｗｈａｔｍａｎガラス繊維ろ紙及び電解液Ｅ８を、径１３．８２ｍｍの電池ケース（宝泉株式会社製　ＣＲ２０３２型コインセルケース）に収容しハーフセルを構成した。これを電池Ｄ－５のハーフセルとした。 The working electrode, counter electrode, 400 μm thick Whatman glass fiber filter paper and electrolyte E8 sandwiched between the two are housed in a battery case (CR 2032 type coin cell case manufactured by Hosen Co., Ltd.) with a diameter of 13.82 mm. A half cell was constructed. This was designated as a half cell of Battery D-5.
（電池Ｄ－６）
　電解液Ｅ１１を用いた以外は、電池Ｄ－５と同様の方法で、電池Ｄ－６のハーフセルを製造した。 (Battery D-6)
A half cell of the battery D-6 was produced in the same manner as the battery D-5 except that the electrolytic solution E11 was used.
（電池Ｄ－７）
　電解液Ｅ１６を用いた以外は、電池Ｄ－５と同様の方法で、電池Ｄ－７のハーフセルを製造した。 (Battery D-7)
A half cell of Battery D-7 was produced in the same manner as Battery D-5, except that Electrolyte E16 was used.
（電池Ｄ－８）
　電解液Ｅ１９を用いた以外は、電池Ｄ－５と同様の方法で、電池Ｄ－８のハーフセルを製造した。 (Battery D-8)
A half cell of the battery D-8 was produced in the same manner as the battery D-5, except that the electrolytic solution E19 was used.
（電池Ｄ－Ｃ３）
　電解液Ｃ５の電解液を用いた以外は、電池Ｄ－５と同様の方法で、電池Ｄ－Ｃ３のハーフセルを製造した。 (Battery D-C3)
A half cell of Battery D-C3 was produced in the same manner as Battery D-5, except that the electrolyte solution of Electrolyte C5 was used.
（評価例Ｄ－３：充放電の可逆性）
　電池Ｄ－５～電池Ｄ－８、電池Ｄ－Ｃ３のハーフセルに対し、２５℃、電圧２．０ＶまでＣＣ充電（定電流充電）し、電圧０．０１ＶまでＣＣ放電(定電流放電)を行う２．０Ｖ－０．０１Ｖの充放電サイクルを、充放電レート０．１Ｃで３サイクル行った。各ハーフセルの充放電曲線を図９３～図９７に示す。 (Evaluation Example D-3: Reversibility of charge / discharge)
The batteries D-5 to D-8 and the battery D-C3 half cells are CC charged (constant current charge) to 25 ° C. and a voltage of 2.0 V, and CC discharged (constant current discharge) to a voltage of 0.01 V. A charge / discharge cycle of 2.0V-0.01V was performed three times at a charge / discharge rate of 0.1C. The charge / discharge curves of each half cell are shown in FIGS.
　図９３～図９７に示されるように、電池Ｄ－５～電池Ｄ－８のハーフセルは、一般的な電解液を用いた電池Ｄ－Ｃ３のハーフセルと同様に、可逆的に充放電反応することがわかる。 As shown in FIGS. 93 to 97, the half cells of the batteries D-5 to D-8 are reversibly charged and discharged similarly to the half cells of the battery D-C3 using a general electrolytic solution. I understand.

Claims (21)

  1. 　正極と負極と電解液とを有する非水系二次電池であって、
    　前記正極は、層状岩塩構造をもつリチウム金属複合酸化物を有する正極活物質をもち、
    　前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、
    　前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする非水系二次電池。     A non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolyte solution,
    The positive electrode has a positive electrode active material having a lithium metal composite oxide having a layered rock salt structure,
    The electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element,
    Regarding the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io. Non-aqueous secondary battery characterized.
  2. 　正極と負極と電解液とを有する非水系二次電池であって、
    　前記正極は、スピネル構造をもつリチウム金属複合酸化物を有する正極活物質をもち、
    　前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、
    　前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする非水系二次電池。     A non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolyte solution,
    The positive electrode has a positive electrode active material having a lithium metal composite oxide having a spinel structure,
    The electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element,
    Regarding the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io. Non-aqueous secondary battery characterized.
  3. 　正極と負極と電解液とを有する非水系二次電池であって、
    　前記正極は、ポリアニオン系材料を有する正極活物質をもち、
    　前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、
    　前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであることを特徴とする非水系二次電池。     A non-aqueous secondary battery having a positive electrode, a negative electrode, and an electrolyte solution,
    The positive electrode has a positive electrode active material having a polyanionic material,
    The electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element,
    Regarding the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io. Non-aqueous secondary battery characterized.
  4. 　正極活物質を有する正極と、負極活物質を有する負極と、電解液とを有する非水系二次電池であって、
    　前記電解液は、アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする金属塩と、ヘテロ元素を有する有機溶媒とを含み、
    　前記電解液の振動分光スペクトルにおける前記有機溶媒由来のピーク強度につき、前記有機溶媒本来のピークの強度をＩｏとし、前記ピークがシフトしたピークの強度をＩｓとした場合、Ｉｓ＞Ｉｏであって、
    　前記非水系二次電池は、Ｌｉ／Ｌｉ+を基準電位としたときの正極の使用最高電位が４．５Ｖ以上であることを特徴とする非水系二次電池。     A non-aqueous secondary battery having a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and an electrolyte solution,
    The electrolytic solution includes a metal salt having a cation of alkali metal, alkaline earth metal or aluminum, and an organic solvent having a hetero element,
    With respect to the peak intensity derived from the organic solvent in the vibrational spectrum of the electrolyte solution, when the intensity of the original peak of the organic solvent is Io and the intensity of the peak shifted from the peak is Is, Is> Io,
    The non-aqueous secondary battery is characterized in that the maximum use potential of the positive electrode when Li / Li + is a reference potential is 4.5 V or more.
  5. 　前記金属塩のカチオンがリチウムである請求項１～４のいずれか１項に記載の非水系二次電池。 The non-aqueous secondary battery according to any one of claims 1 to 4, wherein a cation of the metal salt is lithium.
  6. 　前記金属塩のアニオンの化学構造が、ハロゲン、ホウ素、窒素、酸素、硫黄又は炭素から選択される少なくとも１つの元素を含む請求項１～５のいずれか１項に記載の非水系二次電池。 The non-aqueous secondary battery according to any one of claims 1 to 5, wherein the chemical structure of the anion of the metal salt includes at least one element selected from halogen, boron, nitrogen, oxygen, sulfur, or carbon.
  7. 　前記金属塩のアニオンの化学構造が下記一般式（１）、一般式（２）又は一般式（３）で表される請求項１～６のいずれか１項に記載の非水系二次電池。
    （Ｒ１Ｘ１）（Ｒ２Ｘ２）Ｎ　　　　　　　　　　　　一般式（１）
    （Ｒ１は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　Ｒ２は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒ１とＲ２は、互いに結合して環を形成しても良い。
    　Ｘ１は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲａＰ＝Ｏ、ＲｂＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｘ２は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｃＰ＝Ｏ、ＲｄＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｒａ、Ｒｂ、Ｒｃ、Ｒｄは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒａ、Ｒｂ、Ｒｃ、Ｒｄは、Ｒ１又はＲ２と結合して環を形成しても良い。）
    Ｒ３Ｘ３Ｙ　　　　　　　　　　　　一般式（２）
    （Ｒ３は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　Ｘ３は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｅＰ＝Ｏ、ＲｆＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｒｅ、Ｒｆは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒｅ、Ｒｆは、Ｒ３と結合して環を形成しても良い。
    　Ｙは、Ｏ、Ｓから選択される。）
    （Ｒ４Ｘ４）（Ｒ５Ｘ５）（Ｒ６Ｘ６）Ｃ　　　　　　　　一般式（３）
    （Ｒ４は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　Ｒ５は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　Ｒ６は、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒ４、Ｒ５、Ｒ６のうち、いずれか２つ又は３つが結合して環を形成しても良い。
    　Ｘ４は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｇＰ＝Ｏ、ＲｈＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｘ５は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｉＰ＝Ｏ、ＲｊＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｘ６は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｋＰ＝Ｏ、ＲｌＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｒｇ、Ｒｈ、Ｒｉ、Ｒｊ、Ｒｋ、Ｒｌは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒｇ、Ｒｈ、Ｒｉ、Ｒｊ、Ｒｋ、Ｒｌは、Ｒ４、Ｒ５又はＲ６と結合して環を形成しても良い。）     The nonaqueous secondary battery according to any one of claims 1 to 6, wherein the chemical structure of the anion of the metal salt is represented by the following general formula (1), general formula (2), or general formula (3).
    (R 1 X 1 ) (R 2 X 2 ) N General formula (1)
    (R 1 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted with, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, or an alkoxy group which may be substituted with a substituent , An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
    R 2 represents hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, an alkoxy group which may be substituted with a substituent, Selected from an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, CN, SCN, OCN The
    R 1 and R 2 may be bonded to each other to form a ring.
    X 1 is selected from SO 2 , C = O, C = S, R a P = O, R b P = S, S = O, Si = O.
    X 2 is, SO 2, C = O, C = S, R c P = O, R d P = S, S = O, is selected from Si = O.
    R a , R b , R c , and R d are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a substituent. An unsaturated alkyl group which may be substituted, an unsaturated cycloalkyl group which may be substituted with a substituent, an aromatic group which may be substituted with a substituent, or a heterocyclic group which may be substituted with a substituent , An alkoxy group that may be substituted with a substituent, an unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, and a non-optionally substituted substituent. Selected from saturated thioalkoxy groups, OH, SH, CN, SCN, OCN.
    R a , R b , R c , and R d may be bonded to R 1 or R 2 to form a ring. )
    R 3 X 3 Y General formula (2)
    (R 3 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted with, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, or an alkoxy group which may be substituted with a substituent , An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
    X 3 is selected from SO 2 , C = O, C = S, R e P = O, R f P = S, S = O, and Si = O.
    R e and R f are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a group that may be substituted with a substituent. A saturated alkyl group, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, a heterocyclic group that may be substituted with a substituent, and a substituent An alkoxy group which may be substituted, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, OH , SH, CN, SCN, and OCN.
    R e and R f may combine with R 3 to form a ring.
    Y is selected from O and S. )
    (R 4 X 4) (R 5 X 5) (R 6 X 6) C Formula (3)
    (R 4 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted with, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, or an alkoxy group which may be substituted with a substituent , An unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, an unsaturated thioalkoxy group that may be substituted with a substituent, CN, SCN, or OCN Is done.
    R 5 represents hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, an alkoxy group which may be substituted with a substituent, Selected from an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, CN, SCN, OCN The
    R 6 is hydrogen, halogen, an alkyl group which may be substituted with a substituent, a cycloalkyl group which may be substituted with a substituent, an unsaturated alkyl group which may be substituted with a substituent, or a substituent. An unsaturated cycloalkyl group which may be substituted, an aromatic group which may be substituted with a substituent, a heterocyclic group which may be substituted with a substituent, an alkoxy group which may be substituted with a substituent, Selected from an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, CN, SCN, OCN The
    Further, any two or three of R 4 , R 5 and R 6 may be bonded to form a ring.
    X 4 is, SO 2, C = O, C = S, R g P = O, R h P = S, S = O, is selected from Si = O.
    X 5 is selected from SO 2 , C = O, C = S, R i P = O, R j P = S, S = O, Si = O.
    X 6 is selected from SO 2 , C = O, C = S, R k P = O, R 1 P = S, S = O, Si = O.
    R g , R h , R i , R j , R k , and R l are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, or a cycloalkyl that may be substituted with a substituent. Group, an unsaturated alkyl group that may be substituted with a substituent, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, or a substituent that is substituted with a substituent A heterocyclic group which may be substituted, an alkoxy group which may be substituted with a substituent, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, and a substituent It is selected from an unsaturated thioalkoxy group which may be substituted, OH, SH, CN, SCN, OCN.
    R g , R h , R i , R j , R k , and R l may combine with R 4 , R 5, or R 6 to form a ring. )
  8. 　前記金属塩のアニオンの化学構造が下記一般式（４）、一般式（５）又は一般式（６）で表される請求項１～７のいずれかに記載の非水系二次電池。
    （Ｒ７Ｘ７）（Ｒ８Ｘ８）Ｎ　　　　　　　　　　　　一般式（４）
    （Ｒ７、Ｒ８は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅ（ＣＮ）ｆ（ＳＣＮ）ｇ（ＯＣＮ）ｈである。
    　ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
    　また、Ｒ７とＲ８は、互いに結合して環を形成しても良く、その場合は、２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
    　Ｘ７は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｍＰ＝Ｏ、ＲｎＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｘ８は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｏＰ＝Ｏ、ＲｐＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｒｍ、Ｒｎ、Ｒｏ、Ｒｐは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒｍ、Ｒｎ、Ｒｏ、Ｒｐは、Ｒ７又はＲ８と結合して環を形成しても良い。）
    Ｒ９Ｘ９Ｙ　　　　　　　　　　　　一般式（５）
    （Ｒ９は、ＣｎＨａＦｂＣｌｃＢｒｄＩｅ（ＣＮ）ｆ（ＳＣＮ）ｇ（ＯＣＮ）ｈである。
    　ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
    　Ｘ９は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｑＰ＝Ｏ、ＲｒＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｒｑ、Ｒｒは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒｑ、Ｒｒは、Ｒ９と結合して環を形成しても良い。
    　Ｙは、Ｏ、Ｓから選択される。）
    （Ｒ１０Ｘ１０）（Ｒ１１Ｘ１１）（Ｒ１２Ｘ１２）Ｃ　　　　　一般式（６）
    （Ｒ１０、Ｒ１１、Ｒ１２は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅ（ＣＮ）ｆ（ＳＣＮ）ｇ（ＯＣＮ）ｈである。
    　ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇ、ｈはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
    　Ｒ１０、Ｒ１１、Ｒ１２のうちいずれか２つが結合して環を形成しても良く、その場合、環を形成する基は２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。また、Ｒ１０、Ｒ１１、Ｒ１２の３つが結合して環を形成しても良く、その場合、３つのうち２つの基が２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たし、１つの基が２ｎ－１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ＋ｇ＋ｈを満たす。
    　Ｘ１０は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｓＰ＝Ｏ、ＲｔＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｘ１１は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｕＰ＝Ｏ、ＲｖＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｘ１２は、ＳＯ２、Ｃ＝Ｏ、Ｃ＝Ｓ、ＲｗＰ＝Ｏ、ＲｘＰ＝Ｓ、Ｓ＝Ｏ、Ｓｉ＝Ｏから選択される。
    　Ｒｓ、Ｒｔ、Ｒｕ、Ｒｖ、Ｒｗ、Ｒｘは、それぞれ独立に、水素、ハロゲン、置換基で置換されていても良いアルキル基、置換基で置換されていても良いシクロアルキル基、置換基で置換されていても良い不飽和アルキル基、置換基で置換されていても良い不飽和シクロアルキル基、置換基で置換されていても良い芳香族基、置換基で置換されていても良い複素環基、置換基で置換されていても良いアルコキシ基、置換基で置換されていても良い不飽和アルコキシ基、置換基で置換されていても良いチオアルコキシ基、置換基で置換されていても良い不飽和チオアルコキシ基、ＯＨ、ＳＨ、ＣＮ、ＳＣＮ、ＯＣＮから選択される。
    　また、Ｒｓ、Ｒｔ、Ｒｕ、Ｒｖ、Ｒｗ、Ｒｘは、Ｒ１０、Ｒ１１又はＲ１２と結合して環を形成しても良い。）     The nonaqueous secondary battery according to any one of claims 1 to 7, wherein the chemical structure of the anion of the metal salt is represented by the following general formula (4), general formula (5), or general formula (6).
    (R 7 X 7 ) (R 8 X 8 ) N General formula (4)
    (R 7 and R 8 are each independently C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h .
    n, a, b, c, d, e, f, g, and h are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e + f + g + h.
    R 7 and R 8 may combine with each other to form a ring, in which case 2n = a + b + c + d + e + f + g + h is satisfied.
    X 7 is, SO 2, C = O, C = S, R m P = O, R n P = S, S = O, is selected from Si = O.
    X 8 is selected from SO 2 , C = O, C = S, R o P = O, R p P = S, S = O, Si = O.
    R m , R n , R o , and R p are each independently substituted with hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a substituent. An unsaturated alkyl group which may be substituted, an unsaturated cycloalkyl group which may be substituted with a substituent, an aromatic group which may be substituted with a substituent, or a heterocyclic group which may be substituted with a substituent , An alkoxy group that may be substituted with a substituent, an unsaturated alkoxy group that may be substituted with a substituent, a thioalkoxy group that may be substituted with a substituent, and a non-optionally substituted substituent. Selected from saturated thioalkoxy groups, OH, SH, CN, SCN, OCN.
    R m , R n , R o , and R p may combine with R 7 or R 8 to form a ring. )
    R 9 X 9 Y General formula (5)
    (R 9 is a C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h.
    n, a, b, c, d, e, f, g, and h are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e + f + g + h.
    X 9 is, SO 2, C = O, C = S, R q P = O, R r P = S, S = O, is selected from Si = O.
    R q and R r are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, a cycloalkyl group that may be substituted with a substituent, or a group that may be substituted with a substituent. A saturated alkyl group, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, a heterocyclic group that may be substituted with a substituent, and a substituent An alkoxy group which may be substituted, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, an unsaturated thioalkoxy group which may be substituted with a substituent, OH , SH, CN, SCN, and OCN.
    R q and R r may combine with R 9 to form a ring.
    Y is selected from O and S. )
    (R 10 X 10 ) (R 11 X 11 ) (R 12 X 12 ) C General formula (6)
    (R 10 , R 11 , and R 12 are each independently C n H a F b Cl c Br d I e (CN) f (SCN) g (OCN) h .
    n, a, b, c, d, e, f, g, and h are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e + f + g + h.
    Any two of R 10 , R 11 , and R 12 may combine to form a ring, in which case the group forming the ring satisfies 2n = a + b + c + d + e + f + g + h. Further, three of R 10 , R 11 and R 12 may combine to form a ring, in which case two groups out of the three satisfy 2n = a + b + c + d + e + f + g + h, and one group satisfies 2n−1 = a + b + c + d + e + f + g + h. Fulfill.
    X 10 is, SO 2, C = O, C = S, R s P = O, R t P = S, S = O, is selected from Si = O.
    X 11 is, SO 2, C = O, C = S, R u P = O, R v P = S, S = O, is selected from Si = O.
    X 12 is, SO 2, C = O, C = S, R w P = O, R x P = S, S = O, is selected from Si = O.
    R s , R t , R u , R v , R w , and R x are each independently hydrogen, halogen, an alkyl group that may be substituted with a substituent, or a cycloalkyl that may be substituted with a substituent. Group, an unsaturated alkyl group that may be substituted with a substituent, an unsaturated cycloalkyl group that may be substituted with a substituent, an aromatic group that may be substituted with a substituent, or a substituent that is substituted with a substituent A heterocyclic group which may be substituted, an alkoxy group which may be substituted with a substituent, an unsaturated alkoxy group which may be substituted with a substituent, a thioalkoxy group which may be substituted with a substituent, and a substituent It is selected from an unsaturated thioalkoxy group which may be substituted, OH, SH, CN, SCN, OCN.
    R s , R t , R u , R v , R w , and R x may combine with R 10 , R 11, or R 12 to form a ring. )
  9. 　前記金属塩のアニオンの化学構造が下記一般式（７）、一般式（８）又は一般式（９）で表される請求項１～８のいずれかに記載の非水系二次電池。
    （Ｒ１３ＳＯ２）（Ｒ１４ＳＯ２）Ｎ　　　　　　　　　一般式（７）
    （Ｒ１３、Ｒ１４は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅである。
    　ｎ、ａ、ｂ、ｃ、ｄ、ｅはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。
    　また、Ｒ１３とＲ１４は、互いに結合して環を形成しても良く、その場合は、２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。）
    Ｒ１５ＳＯ３　　　　　　　　　　　　一般式（８）
    （Ｒ１５は、ＣｎＨａＦｂＣｌｃＢｒｄＩｅである。
    　ｎ、ａ、ｂ、ｃ、ｄ、ｅはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。）
    （Ｒ１６ＳＯ２）（Ｒ１７ＳＯ２）（Ｒ１８ＳＯ２）Ｃ　　　一般式（９）
    （Ｒ１６、Ｒ１７、Ｒ１８は、それぞれ独立に、ＣｎＨａＦｂＣｌｃＢｒｄＩｅである。
    　ｎ、ａ、ｂ、ｃ、ｄ、ｅはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。
    　Ｒ１６、Ｒ１７、Ｒ１８のうちいずれか２つが結合して環を形成しても良く、その場合、環を形成する基は２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。また、Ｒ１６、Ｒ１７、Ｒ１８の３つが結合して環を形成しても良く、その場合、３つのうち２つの基が２ｎ＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たし、１つの基が２ｎ－１＝ａ＋ｂ＋ｃ＋ｄ＋ｅを満たす。）     The nonaqueous secondary battery according to any one of claims 1 to 8, wherein the chemical structure of the anion of the metal salt is represented by the following general formula (7), general formula (8), or general formula (9).
    (R 13 SO 2 ) (R 14 SO 2 ) N General formula (7)
    (R 13 and R 14 are each independently C n H a F b Cl c Br d I e .
    n, a, b, c, d, and e are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e.
    R 13 and R 14 may combine with each other to form a ring, in which case 2n = a + b + c + d + e is satisfied. )
    R 15 SO 3 general formula (8)
    (R 15 is a C n H a F b Cl c Br d I e.
    n, a, b, c, d, and e are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e. )
    (R 16 SO 2 ) (R 17 SO 2 ) (R 18 SO 2 ) C General formula (9)
    (R 16 , R 17 , and R 18 are each independently C n H a F b Cl c Br d I e .
    n, a, b, c, d, and e are each independently an integer of 0 or more, and satisfy 2n + 1 = a + b + c + d + e.
    Any two of R 16 , R 17 , and R 18 may combine to form a ring, in which case the group forming the ring satisfies 2n = a + b + c + d + e. Three of R 16 , R 17 and R 18 may combine to form a ring, in which case two groups out of the three satisfy 2n = a + b + c + d + e, and one group satisfies 2n−1 = a + b + c + d + e. Fulfill. )
  10. 　前記金属塩が（ＣＦ３ＳＯ２）２ＮＬｉ、（ＦＳＯ２）２ＮＬｉ、（Ｃ２Ｆ５ＳＯ２）２ＮＬｉ、ＦＳＯ２（ＣＦ３ＳＯ２）ＮＬｉ、（ＳＯ２ＣＦ２ＣＦ２ＳＯ２）ＮＬｉ、又は（ＳＯ２ＣＦ２ＣＦ２ＣＦ２ＳＯ２）ＮＬｉである請求項１～９のいずれかに記載の非水系二次電池。 The metal salt is (CF 3 SO 2 ) 2 NLi, (FSO 2 ) 2 NLi, (C 2 F 5 SO 2 ) 2 NLi, FSO 2 (CF 3 SO 2 ) NLi, (SO 2 CF 2 CF 2 SO 2 The nonaqueous secondary battery according to any one of claims 1 to 9, which is NLi) or (SO 2 CF 2 CF 2 CF 2 SO 2 ) NLi.
  11. 　前記有機溶媒のヘテロ元素が窒素、酸素、硫黄、ハロゲンから選択される少なくとも１つである請求項１～１０のいずれかに記載の非水系二次電池。 The non-aqueous secondary battery according to any one of claims 1 to 10, wherein the hetero element of the organic solvent is at least one selected from nitrogen, oxygen, sulfur, and halogen.
  12. 　前記有機溶媒が非プロトン性溶媒である請求項１～１１のいずれかに記載の非水系二次電池。 The nonaqueous secondary battery according to any one of claims 1 to 11, wherein the organic solvent is an aprotic solvent.
  13. 　前記有機溶媒がアセトニトリル又は１，２－ジメトキシエタンから選択される請求項１～１２のいずれかに記載の非水系二次電池。 The non-aqueous secondary battery according to any one of claims 1 to 12, wherein the organic solvent is selected from acetonitrile or 1,2-dimethoxyethane.
  14. 　前記有機溶媒が下記一般式（１０）で示される鎖状カーボネートから選択される請求項１～１３のいずれか一項に記載の非水系二次電池。
    Ｒ１９ＯＣＯＯＲ２０　　　　　　　　　　　　　　　一般式（１０）
    （Ｒ１９、Ｒ２０は、それぞれ独立に、鎖状アルキルであるＣｎＨａＦｂＣｌｃＢｒｄＩｅ又は、環状アルキルを化学構造に含むＣｍＨｆＦｇＣｌｈＢｒｉＩｊのいずれかから選択される。ｎ、ａ、ｂ、ｃ、ｄ、ｅ、ｍ、ｆ、ｇ、ｈ、ｉ、ｊはそれぞれ独立に０以上の整数であり、２ｎ＋１＝ａ＋ｂ＋ｃ＋ｄ＋ｅ、２ｍ＝ｆ＋ｇ＋ｈ＋ｉ＋ｊを満たす。）     The nonaqueous secondary battery according to any one of claims 1 to 13, wherein the organic solvent is selected from chain carbonates represented by the following general formula (10).
    R 19 OCOOR 20 general formula (10)
    (R 19 and R 20 are each independently C n H a F b Cl c Br d I e which is a chain alkyl, or C m H f F g Cl h Br i I j containing a cyclic alkyl in the chemical structure. N, a, b, c, d, e, m, f, g, h, i, j are each independently an integer of 0 or more, and 2n + 1 = a + b + c + d + e, 2m = f + g + h + i + j Fulfill.)
  15. 　前記有機溶媒がジメチルカーボネート、エチルメチルカーボネート又はジエチルカーボネートから選択される請求項１～１２、及び１４のいずれか一項に記載の非水系二次電池。 The non-aqueous secondary battery according to any one of claims 1 to 12 and 14, wherein the organic solvent is selected from dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate.
  16. 　前記リチウム金属複合酸化物は、一般式：ＬｉａＮｉｂＣｏｃＭｎｄＤｅＯｆ(０．２≦ａ≦１．２、ｂ＋ｃ＋ｄ＋ｅ＝１、０≦ｅ＜１、ＤはＬｉ、Ｆｅ、Ｃｒ、Ｃｕ、Ｚｎ、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ａｌ、Ｚｒ、Ｔｉ、Ｐ、Ｇａ、Ｇｅ、Ｖ、Ｍｏ、Ｎｂ、Ｗ、Ｌａから選ばれる少なくとも１の元素、１．７≦ｆ≦２．１)、及びＬｉ２ＭｎＯ３の群から選ばれる１種からなる請求項１、及び５～１５のいずれか一項に記載の非水系二次電池。 The lithium metal composite oxide has a general formula: Li a Ni b Co c Mn d De O f (0.2 ≦ a ≦ 1.2, b + c + d + e = 1, 0 ≦ e <1, D is Li, Fe, At least one element selected from Cr, Cu, Zn, Ca, Mg, S, Si, Na, K, Al, Zr, Ti, P, Ga, Ge, V, Mo, Nb, W, La, 1.7 The non-aqueous secondary battery according to any one of claims 1 and 5 to 15, comprising at least one selected from the group of ≦ f ≦ 2.1) and Li 2 MnO 3 .
  17. 　前記一般式の中のｂ：ｃ：ｄの比率は、０．５：０．２：０．３、１／３：１／３：１／３、０．７５：０．１０：０．１５、０：０：１、１：０：０、及び０：１：０から選ばれる少なくとも１種類である請求項１６記載の非水系二次電池。 The ratio of b: c: d in the general formula is 0.5: 0.2: 0.3, 1/3: 1/3: 1/3, 0.75: 0.10: 0.15. The non-aqueous secondary battery according to claim 16, which is at least one selected from 0: 0: 1, 1: 0: 0, and 0: 1: 0.
  18. 　前記リチウム金属複合酸化物は、一般式：Ｌｉx(ＡyＭｎ2-y)Ｏ4（Ａは、遷移金属元素、Ｃａ、Ｍｇ、Ｓ、Ｓｉ、Ｎａ、Ｋ、Ａｌ、Ｐ、Ｇａ、及びＧｅから選ばれる少なくとも１種の金属元素、０＜ｘ≦１．２、０＜ｙ≦１）で表される請求項２、及び５～１５のいずれか一項に記載の非水系二次電池。 The lithium metal composite oxide is represented by the general formula: Li x (A y Mn 2 -y) O 4 (A is a transition metal elements, Ca, Mg, S, Si , Na, K, Al, P, Ga, and The nonaqueous secondary battery according to any one of claims 2 and 5 to 15, which is represented by at least one metal element selected from Ge, 0 <x ≦ 1.2, 0 <y ≦ 1) .
  19. 　前記ポリアニオン系材料は、ＬｉＭＰＯ４、ＬｉＭＶＯ４又はＬｉ２ＭＳｉＯ４（式中のＭはＣｏ、Ｎｉ、Ｍｎ、Ｆｅのうちの少なくとも一種から選択される）などで表わされるポリアニオン系化合物からなる請求項３、又は５～１５のいずれか一項に記載の非水系二次電池。 The polyanion material is made of a polyanion compound represented by LiMPO 4 , LiMVO 4 or Li 2 MSiO 4 (wherein M is selected from at least one of Co, Ni, Mn, and Fe). The nonaqueous secondary battery according to any one of 3 and 5 to 15.
  20. 　前記電解液の酸化分解電位は、Ｌｉ／Ｌｉ＋を基準電位としたとき４．５Ｖ以上である請求項４～１５のいずれか一項に記載の非水系二次電池。 The nonaqueous secondary battery according to any one of claims 4 to 15, wherein an oxidative decomposition potential of the electrolytic solution is 4.5 V or more when Li / Li + is used as a reference potential.
  21. 　前記正極活物質はＬｉとＭｎを含むスピネル構造をもつ請求項４～１５、及び２０のいずれか一項に記載の非水系二次電池。 The non-aqueous secondary battery according to any one of claims 4 to 15 and 20, wherein the positive electrode active material has a spinel structure containing Li and Mn.
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