WO2018198618A1 - Non-aqueous electrolyte solution and electricity storage device in which same is used - Google Patents

Non-aqueous electrolyte solution and electricity storage device in which same is used Download PDF

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Publication number
WO2018198618A1
WO2018198618A1 PCT/JP2018/011747 JP2018011747W WO2018198618A1 WO 2018198618 A1 WO2018198618 A1 WO 2018198618A1 JP 2018011747 W JP2018011747 W JP 2018011747W WO 2018198618 A1 WO2018198618 A1 WO 2018198618A1
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carbonate
group
lithium
methyl
electrolytic solution
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PCT/JP2018/011747
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French (fr)
Japanese (ja)
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大希 木戸
近藤　正英
雄一 古藤
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宇部興産株式会社
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Priority to JP2019515159A priority Critical patent/JP7082613B2/en
Publication of WO2018198618A1 publication Critical patent/WO2018198618A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/54—Electrolytes
    • H01G11/58—Liquid electrolytes
    • H01G11/60—Liquid electrolytes characterised by the solvent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/54—Electrolytes
    • H01G11/58—Liquid electrolytes
    • H01G11/62—Liquid electrolytes characterised by the solute, e.g. salts, anions or cations therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/54—Electrolytes
    • H01G11/58—Liquid electrolytes
    • H01G11/64—Liquid electrolytes characterised by additives
    • 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
    • H01M10/0567—Liquid materials characterised by the additives
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M6/00—Primary cells; Manufacture thereof
    • H01M6/14—Cells with non-aqueous electrolyte
    • H01M6/16—Cells with non-aqueous electrolyte with organic electrolyte
    • 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 nonaqueous electrolytic solution capable of improving continuous charging characteristics under a high temperature and high voltage environment, and an electricity storage device using the same.
  • lithium ion secondary batteries and lithium ion capacitors have attracted attention as power sources for automobiles such as electric cars and hybrid cars, and power supplies for idling stops.
  • Patent Document 1 proposes a non-aqueous electrolytic solution containing an alkenyl group-containing chain ester such as allyl methyl carbonate in combination with an ionic liquid, which improves the safety of an electricity storage device at room temperature.
  • the battery characteristics can be improved.
  • the battery when a lithium secondary battery is kept in a continuously charged state for a long time in a high temperature and high voltage environment, the battery has a portion of the nonaqueous solvent in the nonaqueous electrolyte on the surfaces of the positive electrode and the negative electrode.
  • the non-aqueous electrolyte is consumed due to oxidation or reductive decomposition, deposition of decomposed products, and gas generation, resulting in liquid drainage.
  • the non-aqueous electrolyte is withered, the interface resistance between the positive electrode and the negative electrode is increased, and the desirable electrochemical characteristics of the battery are reduced.
  • An object of the present invention is to provide a nonaqueous electrolytic solution capable of improving continuous charging characteristics under a high temperature and high voltage environment, and an electricity storage device using the same.
  • the present invention provides the following (1) to (2).
  • a nonaqueous electrolytic solution for an electricity storage device comprising 0.1 to 30% by mass of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate as an additive.
  • a power storage device including a positive electrode, a negative electrode, and a non-aqueous electrolyte in which an electrolyte salt is dissolved in a non-aqueous solvent, wherein the non-aqueous electrolyte is the non-aqueous electrolyte described in (1).
  • nonaqueous electrolytic solution capable of improving the continuous charging characteristics under a high temperature and high voltage environment, and an electricity storage device such as a lithium battery using the nonaqueous electrolytic solution.
  • the nonaqueous electrolytic solution for an electricity storage device of the present invention is a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, and the nonaqueous electrolytic solution contains a compound represented by the following general formula (I): Containing 0.1 to 4% by mass, and containing 0.1 to 30% by mass of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate as an additive .
  • R 1 represents an alkyl group having 1 to 7 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms
  • R 2 to R 6 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, Or —CH 2 OC ( ⁇ O) OR 7 group
  • R 7 represents an alkyl group having 1 to 4 carbon atoms
  • n 0 or 1
  • the nonaqueous electrolytic solution of the present invention can improve the continuous charging characteristics under a high temperature and high voltage environment. Since the compound represented by the general formula (I) used in the present invention has a cyclohexyl group, the decomposition reaction on the electrode active surface is promoted and a film is rapidly formed. Stability was insufficient. Therefore, when a specific amount of the compound represented by the general formula (I) is used in combination with a specific amount of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate as an additive.
  • one of the carbonates contains not a cyclohexyl group but a phenyl group, sufficient strength cannot be obtained because the formation rate of the resulting film is slow or the constituent components are different.
  • the coating is composed of a compound in which the other substituent R 1 of the carbonate represented by the general formula (I) is an alkyl group or a cycloalkyl group, the film does not interfere with permeation of lithium ions.
  • the continuous charge characteristics under a high temperature and high voltage environment are further improved.
  • the compound contained in the nonaqueous electrolytic solution of the present invention is represented by the following general formula (I).
  • R 1 represents an alkyl group or cycloalkyl group having 1 to 7 carbon atoms, and among them, an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 4 to 6 carbon atoms is preferable, A 1 to 2 alkyl group or a cycloalkyl group having 5 to 6 carbon atoms is preferred.
  • alkyl group having 1 to 7 carbon atoms or the cycloalkyl group having 3 to 6 carbon atoms represented by R 1 specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, and n-butyl. Preferred examples include a straight-chain alkyl group, or a branched alkyl group such as isopropyl group, isobutyl group, sec-butyl group, tert-butyl, and cyclohexylmethyl group.
  • cycloalkyl group examples include a cyclopropyl group And a cyclic alkyl group such as a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group.
  • a methyl group, an ethyl group, an n-propyl group, or a cyclohexyl group is preferable, and a methyl group, an ethyl group, or a cyclohexyl group is more preferable.
  • R 2 to R 6 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a —CH 2 OC ( ⁇ O) OR 7 group,
  • An alkyl group having 1 to 4 carbon atoms is preferred, a hydrogen atom or an alkyl group having 1 to 2 carbon atoms is more preferred, and a hydrogen atom is still more preferred.
  • R 2 to R 6 are an alkyl group having 1 to 4 carbon atoms
  • a linear alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, an isopropyl group
  • Preferred examples include branched alkyl groups such as isobutyl group, sec-butyl group, hydrogen atom, and tert-butyl group.
  • a methyl group, an ethyl group, or an n-propyl group is preferable, and a methyl group or an ethyl group is more preferable.
  • R 7 represents an alkyl group having 1 to 4 carbon atoms, and preferably an alkyl group having 1 to 2 carbon atoms.
  • R 4 is preferable.
  • R 7 include alkyl groups having 1 to 4 carbon atoms, such as a straight-chain alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, isopropyl Preferred examples thereof include branched alkyl groups such as a group, isobutyl group, sec-butyl group, and tert-butyl group. Among these, a methyl group, an ethyl group, or an n-propyl group is preferable, and a methyl group or an ethyl group is more preferable.
  • n represents 0 or 1
  • n is preferably 1 from the viewpoint of enhancing the effect of continuous charge characteristics under a high temperature and high voltage environment.
  • preferred examples when n is 0 or 1 include the following compounds.
  • methylcyclohexyl carbonate (compound A1), methyl (2-methylcyclohexyl) carbonate (compound A2), methyl (3-methylcyclohexyl) carbonate (compound A3), methyl (4-methylcyclohexyl) carbonate (compound A4) ), Methyl (2,3-dimethylcyclohexyl) carbonate (compound A5), methyl (2,4-dimethylcyclohexyl) carbonate (compound A6), methyl (2,5-dimethylcyclohexyl) carbonate (compound A7), methyl (2 , 6-dimethylcyclohexyl) carbonate (compound A8), ethylcyclohexyl carbonate (compound A14), ethyl (2-methylcyclohexyl) carbonate (compound A15), ethyl (3-methylcyclohexane)
  • cyclohexylmethyl methyl carbonate (compound B1), cyclohexylmethyl ethyl carbonate (compound B3), bis (cyclohexylmethyl) carbonate (compound B5), cyclohexane-1,4-diylbis (methylene) dimethylbis (carbonate) ( One or more selected from the group consisting of Compound B6) and cyclohexane-1,4-diylbis (methylene) diethylbis (carbonate) (Compound B7) is preferred, and cyclohexylmethyl methyl carbonate (Compound B1), cyclohexylmethyl ethyl carbonate (Compound One or more selected from the group consisting of B3) and cyclohexane-1,4-diylbis (methylene) dimethylbis (carbonate) (compound B6) is more preferred.
  • the content of the compound represented by the general formula (I) is preferably 0.1 to 4% by mass in the non-aqueous electrolyte. If the content is 4% by mass or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.1% by mass or more, the formation of the film is sufficient and the temperature is high. And the effect of the continuous charge characteristic in a high voltage environment increases.
  • the content is more preferably 0.3% by mass or more, and particularly preferably 0.6% by mass or more.
  • the upper limit is more preferably 3% by mass or less, further preferably 2.2% by mass or less, and particularly preferably 1.7% by mass or less.
  • the additive used in combination with the compound represented by the general formula (I) contains at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate. To do. In these, a fluorine atom containing cyclic carbonate is more preferable.
  • Fluorine atom-containing cyclic carbonates include 4-fluoro-1,3-dioxolan-2-one (FEC), trans or cis-4,5-difluoro-1,3-dioxolan-2-one (hereinafter collectively referred to as both) One or more selected from the group consisting of “DFEC” and the like, and 4-fluoro-1,3-dioxolan-2-one is more preferable.
  • Suitable combinations selected from the group consisting of these fluorine atom-containing cyclic carbonates and unsaturated bond-containing cyclic carbonates include VC and FEC combinations, FEC and DFEC combinations, VC and DFEC combinations, VEC and DFEC combinations, VC And a combination of EC and EEC and a combination of EC and EEC are preferable.
  • a combination of VC and FEC, a combination of VC and DFEC, a combination of VEC and DFEC, and the like are more preferable.
  • the total content of at least one selected from the group consisting of the fluorine atom-containing cyclic carbonate and the unsaturated bond-containing cyclic carbonate is preferably 0.1 to 30% by mass in the non-aqueous electrolyte. If the content is 30% by mass or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.1% by mass or more, the film is sufficiently formed, and the temperature is high. And the effect of the continuous charge characteristic in a high voltage environment increases.
  • the content is preferably 0.5% by mass or more, more preferably 1% by mass or more in the nonaqueous electrolytic solution. Further, the upper limit is preferably 25% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, further preferably 6% by mass or less, and particularly preferably 4% by mass or less.
  • the content ratio (mass ratio) of the compound represented by the general formula (I) and at least one compound selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate is the general formula (I).
  • a / B is preferably in the range of 0.01-3.
  • the content ratio is 3 or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.01 or more, the film is sufficiently formed, and the high temperature and high voltage The effect of continuous charging characteristics in the environment is enhanced.
  • the content ratio is preferably 0.01 or more, more preferably 0.05 or more, and still more preferably 0.2 or more.
  • the upper limit is preferably 3 or less, more preferably 1.8 or less, and the case where the upper limit is 0.6 or less is more preferable because continuous charging characteristics at a higher temperature and a high voltage environment are further improved.
  • Nonaqueous solvent As the non-aqueous solvent used in the non-aqueous electrolyte of the present invention, a cyclic carbonate (however, the non-aqueous solvent excludes a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate; the same shall apply hereinafter), a chain form.
  • a cyclic carbonate Although, the non-aqueous solvent excludes a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate; the same shall apply hereinafter, a chain form.
  • One type or two or more types selected from the group consisting of esters, lactones, ethers and amides are preferred.
  • a cyclic carbonate and a chain ester In order to synergistically improve the continuous charge characteristics in a high temperature and high voltage environment, it is most preferable that both a cyclic carbonate and a chain ester are included.
  • cyclic carbonate examples include one or more selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, and 2,3-butylene carbonate. One or two selected from the group consisting of propylene carbonate are more preferable.
  • the chain ester may be one or more asymmetric chains selected from the group consisting of methyl ethyl carbonate (MEC), methyl propyl carbonate (MPC), methyl isopropyl carbonate (MIPC), methyl butyl carbonate, and ethyl propyl carbonate.
  • One or more symmetrical linear carbonates selected from the group consisting of linear carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, and dibutyl carbonate, methyl pivalate, ethyl pivalate, pivalic acid Pivalate esters such as propyl, methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), and vinegar
  • One or more chain carboxylate selected from the group consisting of butyl suitably.
  • chain esters dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propyl acetate (PA), butyl acetate, methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), and pivalic acid
  • PA propyl acetate
  • MP propionate
  • EP ethyl propionate
  • PP propyl propionate
  • pivalic acid A chain ester having a molecular weight of 90 or more and 120 or less selected from the group consisting of methyl is preferable.
  • a chain carbonate As the chain ester, it is preferable to use two or more. Further, it is more preferable that both a symmetric chain carbonate and an asymmetric chain carbonate are contained, and it is further more preferable that the content of the symmetric chain carbonate is more than that of the asymmetric chain carbonate.
  • the proportion of the volume occupied by the symmetrical linear carbonate in the linear carbonate is preferably 51% by volume or more, and more preferably 55% by volume or more. As the upper limit, 95 volume% or less is preferable and 85 volume% or less is more preferable. It is particularly preferred that the symmetric chain carbonate contains dimethyl carbonate.
  • the asymmetric chain carbonate preferably has a methyl group, and methyl ethyl carbonate is particularly preferable. In the above case, continuous charging characteristics at a higher temperature and a higher voltage environment are improved, which is preferable.
  • the content of the chain ester is not particularly limited, but it is preferably used in the range of 60 to 90% by volume with respect to the total volume of the nonaqueous solvent. If the content is 60% by volume or more, the viscosity of the non-aqueous electrolyte does not become too high, and if it is 90% by volume or less, the electrical conductivity of the non-aqueous electrolyte may decrease and the electrochemical characteristics may decrease. Since it is few, it is preferable that it is the said range.
  • the ratio between the cyclic carbonate and the chain ester is preferably 10:90 to 45:55, and preferably 15:85 to cyclic carbonate: chain ester (volume ratio) from the viewpoint of continuous charge characteristics under a high temperature and high voltage environment. 40:60 is more preferable, and 20:80 to 35:65 is more preferable.
  • nonaqueous solvents include cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, and 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, and the like Preferred is one or more selected from the group consisting of a chain ether, amides such as dimethylformamide, sulfones such as sulfolane, and lactones such as ⁇ -butyrolactone (GBL) or ⁇ -valerolactone, ⁇ -angelicalactone It is mentioned in.
  • ⁇ -butyrolactone GBL
  • ⁇ -valerolactone ⁇ -angelicalactone
  • the other non-aqueous solvents are usually used as a mixture in order to achieve appropriate physical properties.
  • a combination of a cyclic carbonate, a chain ester, and a lactone, or a combination of a cyclic carbonate, a chain ester, and an ether is preferably exemplified, and a combination of a cyclic carbonate, a chain ester, and a lactone is more preferable.
  • lactones ⁇ -butyrolactone (GBL) is more preferred.
  • the content of the other nonaqueous solvent is usually 1% or more, preferably 2% or more, and usually 40% or less, preferably 30% or less, more preferably 20%, based on the total volume of the nonaqueous solvent. It is as follows.
  • additives In the present invention, it is preferable to add other additives to the non-aqueous electrolyte for the purpose of improving the continuous charge characteristics at a higher temperature and a higher voltage environment.
  • additives include the following compounds (A) to (H).
  • (A) Among the polyvalent nitrile compounds at least one selected from the group consisting of adiponitrile, pimelonitrile, suberonitrile, and sebaconitrile having 4 or more carbon chains between the —CN group and the —CN group is more preferable.
  • aromatic compounds one selected from the group consisting of biphenyl, terphenyl (o-, m-, p-isomer), fluorobenzene, cyclohexylbenzene, tert-butylbenzene, and tert-amylbenzene Alternatively, two or more are more preferable, and one or more selected from the group consisting of biphenyl, o-terphenyl, fluorobenzene, cyclohexylbenzene, and tert-amylbenzene are particularly preferable.
  • (C) Among the isocyanate compounds, one or more selected from the group consisting of hexamethylene diisocyanate, octamethylene diisocyanate, 2-isocyanatoethyl acrylate, and 2-isocyanatoethyl methacrylate are more preferable.
  • Triple bond-containing compounds include 2-propynyl-methyl carbonate, 2-propynyl methacrylate, 2-propynyl methanesulfonate, 2-propynyl vinylsulfonate, 2- (methanesulfonyloxy) propionic acid Selected from the group consisting of 2-propynyl, di (2-propynyl) oxalate, methyl-2-propynyl oxalate, ethyl-2-propynyl oxalate, and 2-butyne-1,4-diyl-dimethanesulfonate 1 type or 2 types or more are preferable, and 2-propynyl methanesulfonate, 2-propynyl vinylsulfonate, 2-propynyl 2- (methanesulfonyloxy) propionate, di (2-propynyl) oxalate, and 2- Butyne-1,4-diyl
  • (E) a non-lithium compound containing a cyclic or chain S ⁇ O group selected from the group consisting of sultone, cyclic sulfite, cyclic sulfate, sulfonic acid ester, and vinyl sulfone (however, a triple bond-containing compound, It is preferable to use a specific compound represented by any of the formulas).
  • Examples of the cyclic S ⁇ O group-containing compound include 1,3-propane sultone, 1,3-butane sultone, 1,4-butane sultone, 2,4-butane sultone, 1,3-propene sultone, 2,2-dioxide- 1,2-oxathiolan-4-yl-acetate, 5,5-dimethyl-1,2-oxathiolane-4-one-2,2-dioxide, methylenemethane disulfonate, ethylene sulfite, ethylene sulfate, and 4- ( Preferable examples include one or more selected from the group consisting of (methylsulfonylmethyl) -1,3,2-dioxathiolane-2-oxide.
  • chain-containing S ⁇ O group-containing compound examples include butane-2,3-diyl-dimethanesulfonate, butane-1,4-diyl-dimethanesulfonate, dimethylmethane disulfonate, pentafluorophenylmethanesulfonate, divinyl
  • One or more kinds selected from the group consisting of sulfone and bis (2-vinylsulfonylethyl) ether are preferred.
  • 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, 2,2-dioxide-1,2-oxathiolan-4-yl- 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, 2,2-dioxide-1,2-oxathiolan-4-yl-
  • 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, 2,2-dioxide-1,2-oxathiolan-4-yl- One or more selected from the group consisting of acetate, ethylene sulfate, pentafluorophenyl methanesulfonate, and divinylsulfone are more preferable.
  • 1,3-dioxolane, 5,5-dimethyl-1,3-dioxane, and 5-ethyl-5-methyl-1,3-dioxane are preferable, and 1,3-dioxane and More preferred is 5,5-dimethyl-1,3-dioxane.
  • Phosphorus-containing compounds include tris phosphate (2,2,2-trifluoroethyl), tris phosphate (1,1,1,3,3,3-hexafluoropropan-2-yl), methyl -2- (dimethylphosphoryl) acetate, ethyl-2- (dimethylphosphoryl) acetate, methyl-2- (diethylphosphoryl) acetate, ethyl-2- (diethylphosphoryl) acetate, 2-propynyl-2- (dimethylphosphoryl) acetate 2-propynyl-2- (diethylphosphoryl) acetate, methyl-2- (dimethoxyphosphoryl) acetate, ethyl-2- (dimethoxyphosphoryl) acetate, methyl-2- (diethoxyphosphoryl) acetate, ethyl-2- (di Ethoxyphosphoryl) acetate, 2-propynyl-2- (dimetho Cyphosphoryl) acetate and 2-propyn
  • the total content of the compounds (A) to (H) is preferably 0.01 to 7% by mass in the non-aqueous electrolyte. In this range, the coating film is sufficiently formed without becoming too thick, and the continuous charging characteristics at a higher temperature and a higher voltage environment are further enhanced.
  • the total content is more preferably 0.05% by mass or more, more preferably 0.1% by mass or more in the non-aqueous electrolyte, and the upper limit thereof is more preferably 5% by mass or less, and further preferably 3% by mass or less. preferable.
  • Electrode salt Preferred examples of the electrolyte salt used in the present invention include the following lithium salts.
  • lithium salts include inorganic lithium salts such as LiPF 6 , LiBF 4 and LiClO 4 , LiCF 3 SO 3 , LiC (SO 2 CF 3 ) 3 , LiPF 4 (CF 3 ) 2 , LiPF 3 (C 2 F 5 ) 3.
  • Preferred examples include lithium salts containing a chain-like fluorinated alkyl group, such as LiPF 3 (CF 3 ) 3 , LiPF 3 (iso-C 3 F 7 ) 3 , LiPF 5 (iso-C 3 F 7 ).
  • Favorable examples include at least one lithium salt selected from these, and one or more of these may be used in combination.
  • LiPF 6 and LiBF 4 are preferable, and it is most preferable to use LiPF 6 .
  • the concentration of the electrolyte salt is usually preferably 0.3 M or higher, more preferably 0.7 M or higher, and even more preferably 1.1 M or higher in the nonaqueous electrolytic solution.
  • the upper limit is preferably 2.5M or less, more preferably 2.0M or less, and still more preferably 1.6M or less.
  • the non-aqueous electrolyte further includes a lithium salt (I) having an oxalic acid structure, a lithium salt (II) having a phosphoric acid structure, It is preferable to include at least one lithium salt selected from the group consisting of a lithium salt (III) having an S ⁇ O group and a lithium imide salt (IV) having a fluorine atom.
  • lithium salt (I) having an oxalic acid structure examples include lithium bis (oxalato) borate (LiBOB), lithium difluoro (oxalato) borate (LiDFOB), lithium tetrafluoro (oxalato) phosphate (LiTFOP), and lithium difluorobis (oxalato).
  • LiBOB lithium bis (oxalato) borate
  • LiDFOB lithium difluoro (oxalato) borate
  • LiTFOP lithium tetrafluoro (oxalato) phosphate
  • LiDFOP lithium difluorobis
  • lithium salt (II) having a phosphoric acid structure examples include lithium difluorophosphate (LiPO 2 F 2 ), lithium fluorophosphate (Li 2 PO 3 F), lithium bis (difluorophosphoryl) amide, lithium (difluorophosphoryl) ( Suitable examples include lithium salts having a phosphoric acid structure such as fluorooxide phosphoryl) amide, among which LiPO 2 F 2 and Li 2 PO 3 F are more preferred, and LiPO 2 F 2 is even more preferred.
  • lithium salt (III) having an S ⁇ O group examples include lithium fluorosulfate (FSO 3 Li), lithium methyl sulfate (LMS), lithium ethyl sulfate (LES), lithium 2,2,2-trifluoroethyl sulfate (LFES). ), Lithium trifluoro ((methanesulfonyl) oxy) borate (LiTFMSB), lithium pentafluoro ((methanesulfonyl) oxy) phosphate (LiPFMSP), and among them, LMS, LES, FSO 3 Li, LFES And LiTFMSB are preferred, and LMS and LES are more preferred.
  • LiTFMSB Lithium trifluoro ((methanesulfonyl) oxy) borate
  • LiPFMSP lithium pentafluoro ((methanesulfonyl) oxy) phosphate
  • the content of each salt of lithium salt (I), (II) or (III) is preferably 0.001 to 0.2 M in the non-aqueous electrolyte. If the content is 0.2 M or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered. If 0.001 M or more, the content after continuous charging in a high temperature and high voltage environment is low. The effect of suppressing the decrease in average discharge voltage is sufficient, and the effect of improving battery characteristics after continuous charging is enhanced.
  • the content is preferably 0.01 M or more, more preferably 0.03 M or more, and particularly preferably 0.04 M or more in the nonaqueous electrolytic solution.
  • the upper limit is preferably 0.15M or less, and more preferably 0.12M or less.
  • lithium imide salt (IV) having a fluorine atom As the lithium imide salt (IV) having a fluorine atom, (CF 2 ) 2 (SO 2 ) 2 NLi, (CF 2 ) 3 (SO 2 ) 2 NLi, LiN (SO 2 F) 2 (LiFSI), LiN ( One or more types selected from the group consisting of SO 2 CF 3 ) 2 (LiTFSI) and LiN (SO 2 C 2 F 5 ) 2 are preferably mentioned, and among these, one or more types selected from LiTFSI and LiFSI Is more preferable, and LiFSI is more preferable.
  • the content of the lithium imide salt (IV) is preferably 0.01 to 1M in the nonaqueous electrolytic solution. If the content is 1M or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.01M or more, the average discharge after continuous charging in a high temperature and high voltage environment The effect of suppressing the voltage drop is sufficient, and the effect of improving battery characteristics after continuous charging is enhanced.
  • the content is preferably 0.03M or more, more preferably 0.05M or more in the non-aqueous electrolyte, and the upper limit thereof is preferably 0.9M or less, more preferably 0.7M or less.
  • the nonaqueous electrolytic solution of the present invention is prepared, for example, by mixing the nonaqueous solvent described above with the electrolyte salt and the compound represented by the general formula (I) with respect to the nonaqueous electrolytic solution and a fluorine atom-containing cyclic carbonate. And at least one selected from the group consisting of unsaturated bond-containing cyclic carbonates.
  • the compound added to the non-aqueous solvent and the non-aqueous electrolyte to be used is one that is purified in advance and has as few impurities as possible within a range that does not significantly reduce the productivity.
  • the nonaqueous electrolytic solution of the present invention can be used in the following first to fourth electric storage devices, and as the nonaqueous electrolyte, not only a liquid but also a gelled one can be used. Furthermore, the non-aqueous electrolyte of the present invention can be used for a solid polymer electrolyte.
  • the 1st electrical storage device which uses lithium salt for electrolyte salt (namely, for lithium batteries) or 4th electrical storage device (namely, for lithium ion capacitors), and it uses for lithium batteries More preferably, it is most suitable to be used for a lithium secondary battery.
  • the lithium battery which is the first power storage device according to the present invention, is a generic term for a lithium primary battery and a lithium secondary battery, and the term lithium secondary battery is used as a concept including a so-called lithium ion secondary battery.
  • the lithium battery of the present invention comprises the nonaqueous electrolyte solution in which an electrolyte salt is dissolved in a positive electrode, a negative electrode, and a nonaqueous solvent.
  • Components other than the non-aqueous electrolyte, such as a positive electrode and a negative electrode, can be used without particular limitation.
  • Positive electrode active material for a lithium secondary battery, a composite metal oxide with lithium containing one or more selected from the group consisting of cobalt, manganese, and nickel is used. These positive electrode active materials can be used alone or in combination of two or more.
  • lithium composite metal oxide examples include LiCoO 2 , LiCo 1-x M x O 2 (where M is Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, and One or more elements selected from the group consisting of Cu, 0.001 ⁇ x ⁇ 0.05, LiMn 2 O 4 , LiNiO 2 , LiCo 1-x Ni x O 2 (0.01 ⁇ x ⁇ 1), LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 , LiNi 0 .8 Co 0.15 Al 0.05 O 2 , Li 2 MnO 3 and LiMO 2 (M is a transition metal such as Co, Ni, Mn, and Fe), and LiNi 1/2 Mn 3/2 O one or selected from the group consisting of 4 The above is the more suitable. Moreover, LiCoO 2 and LiMn 2 O 4, LiCoO 2 and LiNiO 2,
  • the continuous charge characteristics under a high temperature and high voltage environment are likely to deteriorate due to a reaction with the electrolyte during charging.
  • the secondary battery it is possible to suppress the deterioration of these electrochemical characteristics.
  • the nonaqueous solvent is generally decomposed on the surface of the positive electrode due to the catalytic action of Ni, and the battery resistance tends to increase.
  • the continuous charge characteristics tend to be deteriorated under a high temperature and high voltage environment.
  • the lithium secondary battery according to the present invention is preferable because it can suppress a decrease in these electrochemical characteristics.
  • the above effect is significant, and more preferably 20 atomic% or more. 30% or more is particularly preferable.
  • LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 , One or more selected from the group consisting of LiNi 0.8 Co 0.15 Al 0.05 O 2 and the like are preferable.
  • lithium-containing olivine-type phosphate can also be used as the positive electrode active material.
  • a lithium-containing olivine-type phosphate containing at least one selected from iron, cobalt, nickel and manganese is preferable. Specific examples thereof include LiFePO 4 , LiCoPO 4 , LiNiPO 4 , LiMnPO 4 , and LiFe 1-x Mn x PO 4 (0.1 ⁇ x ⁇ 0.9).
  • Some of these lithium-containing olivine-type phosphates may be substituted with other elements, and some of iron, cobalt, nickel, and manganese are replaced with Co, Mn, Ni, Mg, Al, B, Ti, V, and Nb.
  • LiFePO 4 and LiMnPO 4 are preferable.
  • mold phosphate can also be mixed with the said positive electrode active material, for example, and can be used. Lithium-containing olivine-type phosphate forms a stable phosphoric acid (PO 4 ) structure and is excellent in thermal stability during charging. Therefore, continuous charging characteristics under high temperature and high voltage environment can be improved.
  • the positive electrode for lithium primary battery CuO, Cu 2 O, Ag 2 O, Ag 2 CrO 4, CuS, CuSO 4, TiO 2, TiS 2, SiO 2, SnO, V 2 O 5, V 6 O 12 , VO x , Nb 2 O 5 , Bi 2 O 3 , Bi 2 Pb 2 O 5 , Sb 2 O 3 , CrO 3 , Cr 2 O 3 , MoO 3 , WO 3 , SeO 2 , MnO 2 , Mn 2 O 3 , Fe 2 O 3 , FeO, Fe 3 O 4 , Ni 2 O 3 , NiO, CoO 3 , CoO and other oxides of one or more metal elements or chalcogen compounds, SO 2 , SOCl 2, etc.
  • Examples thereof include sulfur compounds, and fluorocarbons (fluorinated graphite) represented by the general formula (CF x ) n .
  • fluorocarbons fluorinated graphite represented by the general formula (CF x ) n .
  • MnO 2 , V 2 O 5 , graphite fluoride and the like are preferable.
  • the positive electrode conductive agent is not particularly limited as long as it is an electron conductive material that does not cause a chemical change.
  • Examples thereof include graphite such as natural graphite (such as flake graphite) and artificial graphite, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. Further, graphite and carbon black may be appropriately mixed and used.
  • the addition amount of the conductive agent to the positive electrode mixture is preferably 1 to 10% by mass, and particularly preferably 2 to 5% by mass.
  • the positive electrode is composed of a conductive agent such as acetylene black and carbon black, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of styrene and butadiene (SBR), acrylonitrile and butadiene.
  • a conductive agent such as acetylene black and carbon black, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of styrene and butadiene (SBR), acrylonitrile and butadiene.
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • SBR styrene and butadiene
  • SBR styrene and butadiene
  • acrylonitrile and butadiene acrylonitrile and butadiene.
  • binder such as copolymer (NBR), carb
  • this positive electrode mixture was applied to a current collector aluminum foil, a stainless steel lath plate, etc., dried and pressure-molded, and then subjected to vacuum at a temperature of about 50 ° C. to 250 ° C. for about 2 hours. It can be manufactured by heat treatment.
  • the density of the part except the collector of the positive electrode is usually at 1.5 g / cm 3 or more, for further increasing the capacity of the battery, it is preferably 2 g / cm 3 or more, more preferably, 3 g / cm 3 It is above, More preferably, it is 3.6 g / cm 3 or more.
  • the upper limit is preferably 4 g / cm 3 or less.
  • Examples of the negative electrode active material for a lithium secondary battery include lithium metal, lithium alloy, and carbon material capable of occluding and releasing lithium [easily graphitized carbon and difficult to have a (002) plane spacing of 0.37 nm or more.
  • Graphitized carbon graphite with (002) plane spacing of 0.34 nm or less, etc.], tin (single), tin compound, silicon (single), silicon compound (SiOx: x ⁇ 2), silicon alloy (Si— M alloy: M contains at least one selected from the group consisting of Al, Ni, Cu, Fe, Ti and Mn.), And a group consisting of lithium titanate compounds such as Li 4 Ti 5 O 12 1 type or 2 types or more selected are preferable.
  • a highly crystalline carbon material such as artificial graphite or natural graphite in terms of the ability to occlude and release lithium ions
  • the plane spacing (d 002 ) of the lattice plane ( 002 ) is 0.
  • a carbon material having a graphite type crystal structure of 340 nm (nanometer) or less, particularly 0.335 to 0.337 nm.
  • a mechanical action such as compression force, friction force, shear force, etc. is repeatedly applied to artificial graphite particles having a massive structure in which a plurality of flat graphite fine particles are assembled or bonded non-parallel to each other, for example, scaly natural graphite particles, Using graphite particles that have been subjected to spheroidization treatment, the density of the portion excluding the current collector of the negative electrode can be obtained from X-ray diffraction measurement of the negative electrode sheet when pressed to a density of 1.5 g / cm 3 or more.
  • the graphite crystal It is preferable because the metal elution amount is improved and the charge storage characteristics are improved, more preferably 0.05 or more, and still more preferably 0.1 or more. Moreover, since it may process too much and crystallinity may fall and the discharge capacity of a battery may fall, an upper limit is preferable 0.5 or less, and 0.3 or less is more preferable.
  • the highly crystalline carbon material (core material) is coated with a carbon material that is less crystalline than the core material because continuous charge characteristics under a high temperature and high voltage environment are further improved.
  • the crystallinity of the coating carbon material can be confirmed by a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • Examples of the metal compound capable of inserting and extracting lithium ions as the negative electrode active material include Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Examples thereof include compounds containing at least one metal element such as Cu, Zn, Ag, Mg, Sr, or Ba. These metal compounds may be used in any form such as a simple substance, an alloy, an oxide, a nitride, a sulfide, a boride, and an alloy with lithium, but any of a simple substance, an alloy, an oxide, and an alloy with lithium. Is preferable because the capacity can be increased. Among these, those containing at least one element selected from Si, Ge and Sn are preferable, and those containing at least one element selected from Si and Sn are particularly preferable because the capacity of the battery can be increased.
  • the negative electrode is kneaded using the same conductive agent, binder, and high-boiling solvent as in the production of the positive electrode, and then the negative electrode mixture is applied to the copper foil of the current collector. After being dried and pressure-molded, it can be produced by heat treatment under vacuum at a temperature of about 50 ° C. to 250 ° C. for about 2 hours.
  • the density of the portion excluding the current collector of the negative electrode is usually 1.1 g / cm 3 or more, and is preferably 1.5 g / cm 3 or more, particularly preferably 1.7 g in order to further increase the capacity of the battery. / Cm 3 or more.
  • the upper limit is preferably 2 g / cm 3 or less.
  • examples of the negative electrode active material for a lithium primary battery include lithium metal and lithium alloy.
  • the structure of the lithium battery is not particularly limited, and a coin-type battery, a cylindrical battery, a square battery, a laminated battery, or the like having a single-layer or multi-layer separator can be applied. Although it does not restrict
  • the lithium secondary battery of the present invention is excellent in continuous charge characteristics under a high temperature and high voltage environment even when the end-of-charge voltage is 4.2 V or higher, particularly 4.3 V or higher, and is also characteristic at 4.4 V or higher. Is good.
  • the end-of-discharge voltage is usually 2.8 V or higher, and more preferably 2.5 V or higher, but the lithium secondary battery in the present invention can be 2.0 V or higher.
  • the current value is not particularly limited, but is usually used in the range of 0.1 to 30C. Further, the lithium battery in the present invention can be charged / discharged at ⁇ 40 to 100 ° C., preferably ⁇ 10 to 80 ° C.
  • a method of providing a safety valve on the battery lid or cutting a member such as a battery can or a gasket can be employed.
  • the battery lid can be provided with a current interruption mechanism that senses the internal pressure of the battery and interrupts the current.
  • the 2nd electrical storage device which concerns on this invention is an electrical storage device which stores the energy using the electric double layer capacity
  • An example of the present invention is an electric double layer capacitor.
  • the most typical electrode active material used for this electricity storage device is activated carbon. Double layer capacity increases roughly in proportion to surface area.
  • the 3rd electrical storage device which concerns on this invention is an electrical storage device which stores the energy using the dope / dedope reaction of an electrode including the non-aqueous electrolyte of this invention.
  • the electrode active material used in this power storage device include metal oxides such as ruthenium oxide, iridium oxide, tungsten oxide, molybdenum oxide, and copper oxide, and ⁇ -conjugated polymers such as polyacene and polythiophene derivatives. Capacitors using these electrode active materials can store energy associated with electrode doping / dedoping reactions.
  • the 4th electrical storage device which concerns on this invention is an electrical storage device which stores the energy using the intercalation of the lithium ion to carbon materials, such as graphite which is a negative electrode, containing the non-aqueous electrolyte of this invention. It is called a lithium ion capacitor (LIC).
  • the positive electrode include those using an electric double layer between an activated carbon electrode and an electrolytic solution, and those using a ⁇ -conjugated polymer electrode doping / dedoping reaction.
  • the electrolyte contains at least a lithium salt such as LiPF 6 .
  • Examples 1 to 45, Comparative Examples 1 to 4 [Production of lithium ion secondary battery] 92% by mass of LiNi 0.8 Co 0.1 Mn 0.1 O 2 and 5% by mass of acetylene black (conductive agent) are mixed, and 3% by mass of polyvinylidene fluoride (binder) is previously added to 1-methyl-2-
  • a positive electrode mixture paste was prepared by adding to and mixing with the solution dissolved in pyrrolidone. This positive electrode mixture paste was applied to one side of an aluminum foil (current collector), dried and pressurized, and cut into a predetermined size to produce a positive electrode sheet. The density of the portion excluding the current collector of the positive electrode was 3.6 g / cm 3 .
  • a negative electrode mixture paste was prepared by adding to the dissolved solution and mixing. This negative electrode mixture paste was applied to one side of a copper foil (current collector), dried and pressurized, and cut into a predetermined size to produce a negative electrode sheet. The density of the portion excluding the current collector of the negative electrode was 1.5 g / cm 3 .
  • Average discharge voltage change rate (relative value) (%) (initial average discharge voltage ⁇ average discharge voltage after continuous charge) / (initial average discharge voltage in comparative example 1 ⁇ average discharge after continuous charge in comparative example 1) Voltage) x 100
  • the capacity recovery rate and the average discharge voltage reduction rate after high-temperature storage were also insufficient.
  • the effects of the present invention are as follows.
  • a specific amount of the compound represented by the general formula (I) of the present invention, a fluorine atom-containing cyclic carbonate It has been found that the effect is unique when at least one selected from the group consisting of saturated bond-containing cyclic carbonates is contained in combination.
  • non-aqueous electrolyte of the present invention also has an effect of improving the capacity recovery rate and average discharge voltage reduction rate after high-temperature storage such as lithium ion capacitors and lithium air batteries.

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Abstract

The present invention is: a non-aqueous electrolyte solution for an electricity storage device in which an electrolytic salt is dissolved in a non-aqueous solvent, wherein the non-aqueous electrolyte solution is characterized by containing 0.1-4% by mass of a compound represented by general formula (I), and containing 0.1-30% by mass of at least one selected from the group consisting of fluorine-containing cyclic carbonates and unsaturated-bond-containing cyclic carbonates as an additive; and an electricity storage device in which it is possible to improve continuous charging characteristics in a high-temperature, high-voltage environment. (In the formula, R1 represents a C1-7 alkyl group or a C3-6 cycloalkyl group; R2 through R6 each independently represent a hydrogen atom, a C1-4 alkyl group, or a -CH2OC(=O)OR7 group; R7 represents a C1-4 alkyl group; and n is 0 or 1.)

Description

非水電解液及びそれを用いた蓄電デバイスNon-aqueous electrolyte and power storage device using the same
　本発明は、高温かつ高電圧環境下での連続充電特性を向上できる非水電解液及びそれを用いた蓄電デバイスに関する。 The present invention relates to a nonaqueous electrolytic solution capable of improving continuous charging characteristics under a high temperature and high voltage environment, and an electricity storage device using the same.
　近年、電気自動車やハイブリッドカー等の自動車用電源や、アイドリングストップ用電源として、リチウムイオン二次電池及びリチウムイオンキャパシタが注目されている。 In recent years, lithium ion secondary batteries and lithium ion capacitors have attracted attention as power sources for automobiles such as electric cars and hybrid cars, and power supplies for idling stops.
　リチウム二次電池の電解液としては、エチレンカーボネート、プロピレンカーボネート等の環状カーボネートと、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鎖状カーボネートに、ＬｉＰＦ６、ＬｉＢＦ４等の電解質塩を溶解させた非水電解液が用いられている。
　こうしたリチウム二次電池のサイクル特性、保存特性等の電池特性を改良するために、これらの非水電解液に用いられる非水系溶媒や電解質塩について種々の検討がなされている。 As an electrolyte for a lithium secondary battery, an electrolyte salt such as LiPF 6 or LiBF 4 was dissolved in a cyclic carbonate such as ethylene carbonate or propylene carbonate, and a chain carbonate such as dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate. A non-aqueous electrolyte is used.
In order to improve battery characteristics such as cycle characteristics and storage characteristics of such lithium secondary batteries, various studies have been made on non-aqueous solvents and electrolyte salts used in these non-aqueous electrolytes.
　例えば、特許文献１には、アリルメチルカーボネート等のアルケニル基含有鎖状エステルをイオン液体と組み合わせて含有する非水電解液が提案されており、蓄電デバイスの安全性を向上し、室温下での電池特性を改善することができるとしている。 For example, Patent Document 1 proposes a non-aqueous electrolytic solution containing an alkenyl group-containing chain ester such as allyl methyl carbonate in combination with an ionic liquid, which improves the safety of an electricity storage device at room temperature. The battery characteristics can be improved.
　ところで、リチウム二次電池を高温かつ高電圧環境下で、連続充電の状態で長期間保持した場合に、電池は正極及び負極の表面上で、非水電解液中の非水溶媒の一部が酸化又は還元分解してしまい、分解物の沈着やガス発生により非水電解液が消費され、液枯れを起こすという問題がある。非水電解液の液枯れが起こると正極及び負極の界面抵抗が増大し、電池の望ましい電気化学特性が低下する。
　特許文献１で提案された、アリルメチルカーボネートやメチルシクロヘキシルカーボネートをイオン液体と共に添加した電解液では、高温かつ高電圧環境下、連続充電を長期間行った後の放電電圧低下の抑制に対して何らの記載も示唆もなく、十分な前記抑制効果が得られていないのが実情である。 By the way, when a lithium secondary battery is kept in a continuously charged state for a long time in a high temperature and high voltage environment, the battery has a portion of the nonaqueous solvent in the nonaqueous electrolyte on the surfaces of the positive electrode and the negative electrode. There is a problem that the non-aqueous electrolyte is consumed due to oxidation or reductive decomposition, deposition of decomposed products, and gas generation, resulting in liquid drainage. When the non-aqueous electrolyte is withered, the interface resistance between the positive electrode and the negative electrode is increased, and the desirable electrochemical characteristics of the battery are reduced.
In the electrolyte solution in which allyl methyl carbonate or methyl cyclohexyl carbonate is added together with the ionic liquid proposed in Patent Document 1, there is nothing to suppress the discharge voltage drop after continuous charging for a long time in a high temperature and high voltage environment. In fact, there is no description or suggestion, and a sufficient suppression effect is not obtained.
特開２００８－１２３８９８号公報JP 2008-123898 A
　本発明は、高温かつ高電圧環境下での連続充電特性を向上させることができる非水電解液及びそれを用いた蓄電デバイスを提供することを目的とする。 An object of the present invention is to provide a nonaqueous electrolytic solution capable of improving continuous charging characteristics under a high temperature and high voltage environment, and an electricity storage device using the same.
　本発明者らは、上記従来技術の非水電解液の性能について詳細に検討した結果、前記特許文献１に記載のアリルメチルカーボネートやメチルシクロヘキシルカーボネートを実際に非水電解液に添加して評価したところ高温かつ高電圧環境下での連続充電特性は不十分であることが判明した。
　そこで、本発明者らは、上記課題を解決するために鋭意研究を重ね、非水溶媒に電解質塩が溶解されている非水電解液において、非水電解液中に下記一般式（Ｉ）で表される特定の化合物を特定量と、更にフッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を特定量添加した非水電解液を用いることにより、高温かつ高電圧環境下での連続充電特性が格段に向上することを見出し、本発明を完成した。 As a result of detailed studies on the performance of the above-described conventional non-aqueous electrolyte, the present inventors actually added and evaluated allyl methyl carbonate and methyl cyclohexyl carbonate described in Patent Document 1 to the non-aqueous electrolyte. However, it was found that the continuous charge characteristics under high temperature and high voltage environment are insufficient.
Therefore, the inventors of the present invention have made extensive studies to solve the above problems, and in a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a non-aqueous solvent, the following general formula (I) is contained in the non-aqueous electrolyte solution. By using a non-aqueous electrolyte to which a specific amount of the specific compound represented and a specific amount of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate is added, The present inventors have found that the continuous charging characteristics under a voltage environment are remarkably improved.
すなわち、本発明は、下記の（１）～（２）を提供するものである。
（１）非水溶媒に電解質塩が溶解されている非水電解液であって、非水電解液中に下記一般式（Ｉ）で表される化合物を０．１～４質量％含有し、添加剤としてフッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を０．１～３０質量％含有することを特徴とする蓄電デバイス用非水電解液。 That is, the present invention provides the following (1) to (2).
(1) A nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution containing 0.1 to 4% by mass of a compound represented by the following general formula (I), A nonaqueous electrolytic solution for an electricity storage device, comprising 0.1 to 30% by mass of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate as an additive.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
（式中、Ｒ１は炭素数１～７のアルキル基又は炭素数３～６のシクロアルキル基を示し、Ｒ2～Ｒ6はそれぞれ独立に、水素原子、炭素数１～４のアルキル基、又は－ＣＨ２ＯＣ（＝Ｏ）ＯＲ７基を示し、Ｒ７は炭素数１～４のアルキル基を示し、ｎ＝０又は１を示す。）
　（２）正極、負極、及び非水溶媒に電解質塩が溶解されている非水電解液を備えた蓄電デバイスであって、該非水電解液が前記（１）に記載の非水電解液であることを特徴とする蓄電デバイス。 (Wherein R 1 represents an alkyl group having 1 to 7 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and R 2 to R 6 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, Or —CH 2 OC (═O) OR 7 group, R 7 represents an alkyl group having 1 to 4 carbon atoms, and n = 0 or 1).
(2) A power storage device including a positive electrode, a negative electrode, and a non-aqueous electrolyte in which an electrolyte salt is dissolved in a non-aqueous solvent, wherein the non-aqueous electrolyte is the non-aqueous electrolyte described in (1). An electricity storage device characterized by the above.
　本発明によれば、高温かつ高電圧環境下での連続充電特性を向上できる非水電解液及びそれを用いたリチウム電池等の蓄電デバイスを提供することができる。 According to the present invention, it is possible to provide a nonaqueous electrolytic solution capable of improving the continuous charging characteristics under a high temperature and high voltage environment, and an electricity storage device such as a lithium battery using the nonaqueous electrolytic solution.
〔非水電解液〕
　本発明の蓄電デバイス用非水電解液は、非水溶媒に電解質塩が溶解されている非水電解液であって、非水電解液中に、下記一般式（Ｉ）で表される化合物を０．１～４質量％含有し、添加剤としてフッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を０．１～３０質量％を含有することを特徴とする。 [Non-aqueous electrolyte]
The nonaqueous electrolytic solution for an electricity storage device of the present invention is a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, and the nonaqueous electrolytic solution contains a compound represented by the following general formula (I): Containing 0.1 to 4% by mass, and containing 0.1 to 30% by mass of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate as an additive .
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
（式中、Ｒ１は炭素数１～７のアルキル基又は炭素数３～６のシクロアルキル基を示し、Ｒ2～Ｒ6はそれぞれ独立に、水素原子、炭素数１～４のアルキル基、又は－ＣＨ２ＯＣ（＝Ｏ）ＯＲ７基を示し、Ｒ７は炭素数１～４のアルキル基を示し、ｎ＝０又は１を示す。） (Wherein R 1 represents an alkyl group having 1 to 7 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and R 2 to R 6 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, Or —CH 2 OC (═O) OR 7 group, R 7 represents an alkyl group having 1 to 4 carbon atoms, and n = 0 or 1).
　本発明の非水電解液が、高温かつ高電圧環境下での連続充電特性を向上できる理由は必ずしも明らかではないが、以下のように考えられる。
　本発明で使用される一般式（Ｉ）で表される化合物は、シクロヘキシル基を有しているため、電極活性表面での分解反応が促進され素早く被膜を形成されるものの、単独では被膜の熱安定性が不十分であった。そこで、特定量の一般式（Ｉ）で表される化合物と、更に添加剤として、フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を特定量組み合わせて使用すると、「シクロヘキシル基」、「－Ｏ－Ｃ（＝Ｏ）－Ｏ－基」、「フッ素原子含有環状カーボネート又は不飽和結合含有環状カーボネート」の少なくとも３種の特性基を含む熱安定性の高い強固な混合被膜を形成すると考えられる。
　ここで、カーボネートの一方がシクロヘキシル基ではなく、フェニル基を含む場合は、得られる被膜の形成速度が遅かったり、構成成分が異なるためか十分な強度が得られない。また、本発明においては、一般式（Ｉ）で表されるカーボネートの他方の置換基Ｒ１がアルキル基又はシクロアルキル基である化合物で被膜が構成されるため、リチウムイオンの透過を妨げない適度な柔軟性をもった被膜が形成され、更なる溶媒の分解を抑制した結果、高温かつ高電圧環境下での連続充電特性がより一層向上すると考えられる。 The reason why the nonaqueous electrolytic solution of the present invention can improve the continuous charging characteristics under a high temperature and high voltage environment is not necessarily clear, but is considered as follows.
Since the compound represented by the general formula (I) used in the present invention has a cyclohexyl group, the decomposition reaction on the electrode active surface is promoted and a film is rapidly formed. Stability was insufficient. Therefore, when a specific amount of the compound represented by the general formula (I) is used in combination with a specific amount of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate as an additive. , “Cyclohexyl group”, “—O—C (═O) —O— group”, “fluorine atom-containing cyclic carbonate or unsaturated bond-containing cyclic carbonate” and at least three kinds of characteristic groups having high thermal stability and strong It is thought that a mixed film is formed.
Here, when one of the carbonates contains not a cyclohexyl group but a phenyl group, sufficient strength cannot be obtained because the formation rate of the resulting film is slow or the constituent components are different. In the present invention, since the coating is composed of a compound in which the other substituent R 1 of the carbonate represented by the general formula (I) is an alkyl group or a cycloalkyl group, the film does not interfere with permeation of lithium ions. As a result of the formation of a flexible film and the suppression of further solvent decomposition, it is considered that the continuous charge characteristics under a high temperature and high voltage environment are further improved.
　本発明の非水電解液に含まれる化合物は、下記一般式（Ｉ）で表される。 The compound contained in the nonaqueous electrolytic solution of the present invention is represented by the following general formula (I).
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　前記一般式（Ｉ）において、Ｒ１は炭素数１～７のアルキル基又はシクロアルキル基を示し、中でも炭素数１～４のアルキル基又は炭素数４～６のシクロアルキル基が好ましく、炭素数１～２のアルキル基又は炭素数５～６のシクロアルキル基が好ましい。 In the general formula (I), R 1 represents an alkyl group or cycloalkyl group having 1 to 7 carbon atoms, and among them, an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 4 to 6 carbon atoms is preferable, A 1 to 2 alkyl group or a cycloalkyl group having 5 to 6 carbon atoms is preferred.
　前記Ｒ１で表される炭素数１～７のアルキル基又は炭素数３～６のシクロアルキル基において、アルキル基の具体例としては、メチル基、エチル基、ｎ－プロピル基、ｎ－ブチル等の直鎖のアルキル基、又はイソプロピル基、イソブチル基、sec－ブチル基、tert－ブチル、シクロヘキシルメチル基等の分岐のアルキル基が好適に挙げられ、シクロアルキル基の具体例としては、シクロプロピル基、シクロブチル基、シクロペンチル基、もしくはシクロヘキシル基等の環状アルキル基が好適に挙げられる。これらの中でもメチル基、エチル基、ｎ－プロピル基、又はシクロヘキシル基が好ましく、メチル基、エチル基又はシクロヘキシル基がより好ましい。 In the alkyl group having 1 to 7 carbon atoms or the cycloalkyl group having 3 to 6 carbon atoms represented by R 1 , specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, and n-butyl. Preferred examples include a straight-chain alkyl group, or a branched alkyl group such as isopropyl group, isobutyl group, sec-butyl group, tert-butyl, and cyclohexylmethyl group. Specific examples of the cycloalkyl group include a cyclopropyl group And a cyclic alkyl group such as a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group. Among these, a methyl group, an ethyl group, an n-propyl group, or a cyclohexyl group is preferable, and a methyl group, an ethyl group, or a cyclohexyl group is more preferable.
　前記一般式（Ｉ）において、前記Ｒ２～Ｒ６はそれぞれ独立に、水素原子、炭素数１～４のアルキル基、又は－ＣＨ２ＯＣ（＝Ｏ）ＯＲ７基を示し、水素原子又は炭素数１～４のアルキル基が好ましく、水素原子又は炭素数１～２のアルキル基がより好ましく、水素原子が更に好ましい。 In the general formula (I), R 2 to R 6 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a —CH 2 OC (═O) OR 7 group, An alkyl group having 1 to 4 carbon atoms is preferred, a hydrogen atom or an alkyl group having 1 to 2 carbon atoms is more preferred, and a hydrogen atom is still more preferred.
　前記Ｒ２～Ｒ６が炭素数１～４のアルキル基である場合の具体例としては、メチル基、エチル基、ｎ－プロピル基、ｎ－ブチル基等の直鎖のアルキル基、イソプロピル基、イソブチル基、sec－ブチル基、水素原子、tert－ブチル基等の分岐のアルキル基が好適に挙げられる。これらの中でもメチル基、エチル基、又はｎ－プロピル基が好ましく、メチル基又はエチル基がより好ましい。 Specific examples of the case where R 2 to R 6 are an alkyl group having 1 to 4 carbon atoms include a linear alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, an isopropyl group, Preferred examples include branched alkyl groups such as isobutyl group, sec-butyl group, hydrogen atom, and tert-butyl group. Among these, a methyl group, an ethyl group, or an n-propyl group is preferable, and a methyl group or an ethyl group is more preferable.
　前記Ｒ２～Ｒ６が－ＣＨ２ＯＣ（＝Ｏ）ＯＲ７基である場合、Ｒ７は炭素数１～４のアルキル基を示し、炭素数１～２のアルキル基が好ましい。
　前記－ＣＨ２ＯＣ（＝Ｏ）ＯＲ７基の置換位置としては、Ｒ４が好ましい。 When R 2 to R 6 are —CH 2 OC (═O) OR 7 groups, R 7 represents an alkyl group having 1 to 4 carbon atoms, and preferably an alkyl group having 1 to 2 carbon atoms.
As the substitution position of the —CH 2 OC (═O) OR 7 group, R 4 is preferable.
　前記Ｒ７の具体例としては、炭素数１～４のアルキル基である場合の具体例としては、メチル基、エチル基、ｎ－プロピル基、ｎ－ブチル基等の直鎖のアルキル基、イソプロピル基、イソブチル基、sec－ブチル基、tert－ブチル基等の分岐のアルキル基が好適に挙げられる。これらの中でもメチル基、エチル基、又はｎ－プロピル基が好ましく、メチル基又はエチル基がより好ましい。 Specific examples of R 7 include alkyl groups having 1 to 4 carbon atoms, such as a straight-chain alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, isopropyl Preferred examples thereof include branched alkyl groups such as a group, isobutyl group, sec-butyl group, and tert-butyl group. Among these, a methyl group, an ethyl group, or an n-propyl group is preferable, and a methyl group or an ethyl group is more preferable.
　前記一般式（Ｉ）において、ｎは０又は１を示し、高温かつ高電圧環境下での連続充電特性の効果を高める観点から、ｎは１が好ましい。
　前記一般式（Ｉ）において、ｎが０又は１の場合の好適例としては、以下の化合物が挙げられる。 In the general formula (I), n represents 0 or 1, and n is preferably 1 from the viewpoint of enhancing the effect of continuous charge characteristics under a high temperature and high voltage environment.
In the general formula (I), preferred examples when n is 0 or 1 include the following compounds.
[ｎ＝０の場合]
Figure JPOXMLDOC01-appb-C000005
 [When n = 0]
Figure JPOXMLDOC01-appb-C000005
　上記化合物の中でも、メチルシクロヘキシルカーボネート（化合物Ａ１）、メチル（２－メチルシクロヘキシル）カーボネート（化合物Ａ２）、メチル（３－メチルシクロヘキシル）カーボネート（化合物Ａ３）、メチル（４－メチルシクロヘキシル）カーボネート（化合物Ａ４）、メチル（２、３－ジメチルシクロヘキシル）カーボネート（化合物Ａ５）、メチル（２、４－ジメチルシクロヘキシル）カーボネート（化合物Ａ６）、メチル（２、５－ジメチルシクロヘキシル）カーボネート（化合物Ａ７）、メチル（２、６－ジメチルシクロヘキシル）カーボネート（化合物Ａ８）、エチルシクロヘキシルカーボネート（化合物Ａ１４）、エチル（２－メチルシクロヘキシル）カーボネート（化合物Ａ１５）、エチル（３－メチルシクロヘキシル）カーボネート（化合物Ａ１６）、エチル（４－メチルシクロヘキシル）カーボネート（化合物Ａ１７）、及びジシクロヘキシルカーボネート（化合物Ａ１８）からなる群より選ばれる１種以上が好ましく、メチルシクロヘキシルカーボネート（化合物Ａ１）、メチル（２－メチルシクロヘキシル）カーボネート（化合物Ａ２）、メチル（３－メチルシクロヘキシル）カーボネート（化合物Ａ３）、メチル（４－メチルシクロヘキシル）カーボネート（化合物Ａ４）、エチルシクロヘキシルカーボネート（化合物１４）、エチル（２－メチルシクロヘキシル）カーボネート（化合物Ａ１５）、エチル（３－メチルシクロヘキシル）カーボネート（化合物Ａ１６）、エチル（４－メチルシクロヘキシル）カーボネート（化合物Ａ１７）、及びジシクロヘキシルカーボネート（化合物Ａ１８）からなる群より選ばれる１種以上がより好ましく、メチルシクロヘキシルカーボネート（化合物Ａ１）、エチルシクロヘキシルカーボネート（化合物Ａ１４）、及びジシクロヘキシルカーボネート（化合物Ａ１８）からなる群より選ばれる１種以上が更に好ましい。 Among the above compounds, methylcyclohexyl carbonate (compound A1), methyl (2-methylcyclohexyl) carbonate (compound A2), methyl (3-methylcyclohexyl) carbonate (compound A3), methyl (4-methylcyclohexyl) carbonate (compound A4) ), Methyl (2,3-dimethylcyclohexyl) carbonate (compound A5), methyl (2,4-dimethylcyclohexyl) carbonate (compound A6), methyl (2,5-dimethylcyclohexyl) carbonate (compound A7), methyl (2 , 6-dimethylcyclohexyl) carbonate (compound A8), ethylcyclohexyl carbonate (compound A14), ethyl (2-methylcyclohexyl) carbonate (compound A15), ethyl (3-methylcyclohexane) One or more selected from the group consisting of (xyl) carbonate (compound A16), ethyl (4-methylcyclohexyl) carbonate (compound A17), and dicyclohexyl carbonate (compound A18) are preferred, and methylcyclohexyl carbonate (compound A1), methyl ( 2-methylcyclohexyl) carbonate (compound A2), methyl (3-methylcyclohexyl) carbonate (compound A3), methyl (4-methylcyclohexyl) carbonate (compound A4), ethylcyclohexyl carbonate (compound 14), ethyl (2-methyl) Cyclohexyl) carbonate (compound A15), ethyl (3-methylcyclohexyl) carbonate (compound A16), ethyl (4-methylcyclohexyl) carbonate (compound A17) And at least one selected from the group consisting of dicyclohexyl carbonate (compound A18), more preferably 1 selected from the group consisting of methylcyclohexyl carbonate (compound A1), ethylcyclohexyl carbonate (compound A14), and dicyclohexyl carbonate (compound A18). More than species are more preferred.
[ｎ＝１の場合]
Figure JPOXMLDOC01-appb-C000006
  [When n = 1]
Figure JPOXMLDOC01-appb-C000006
　上記化合物の中でも、シクロヘキシルメチルメチルカーボネート（化合物Ｂ１）、シクロヘキシルメチルエチルカーボネート（化合物Ｂ３）、ビス（シクロヘキシルメチル）カーボネート（化合物Ｂ５）、シクロヘキサン－１，４－ジイルビス（メチレン）ジメチルビス（カーボネート）（化合物Ｂ６）、及びシクロヘキサン－１，４－ジイルビス（メチレン）ジエチルビス（カーボネート）（化合物Ｂ７）からなる群より選ばれる１種以上が好ましく、シクロヘキシルメチルメチルカーボネート（化合物Ｂ１）、シクロヘキシルメチルエチルカーボネート（化合物Ｂ３）、及びシクロヘキサン－１，４－ジイルビス（メチレン）ジメチルビス（カーボネート）（化合物Ｂ６）からなる群より選ばれる１種以上がより好ましい。 Among the above compounds, cyclohexylmethyl methyl carbonate (compound B1), cyclohexylmethyl ethyl carbonate (compound B3), bis (cyclohexylmethyl) carbonate (compound B5), cyclohexane-1,4-diylbis (methylene) dimethylbis (carbonate) ( One or more selected from the group consisting of Compound B6) and cyclohexane-1,4-diylbis (methylene) diethylbis (carbonate) (Compound B7) is preferred, and cyclohexylmethyl methyl carbonate (Compound B1), cyclohexylmethyl ethyl carbonate (Compound One or more selected from the group consisting of B3) and cyclohexane-1,4-diylbis (methylene) dimethylbis (carbonate) (compound B6) is more preferred.
　本発明の非水電解液において、一般式（Ｉ）で表される化合物の含有量は、非水電解液中に０．１～４質量％が好ましい。該含有量が４質量％以下であれば、電極上に過度に被膜が形成され電気化学特性が低下するおそれが少なく、また０．１質量％以上であれば被膜の形成が十分であり、高温かつ高電圧環境下での連続充電特性の効果が高まる。該含有量は、０．３質量％以上が更に好ましく、０．６質量％以上が特に好ましい。また、その上限は、３質量％以下がより好ましく、２．２質量％以下が更に好ましく、１．７質量％以下が特に好ましい。 In the non-aqueous electrolyte of the present invention, the content of the compound represented by the general formula (I) is preferably 0.1 to 4% by mass in the non-aqueous electrolyte. If the content is 4% by mass or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.1% by mass or more, the formation of the film is sufficient and the temperature is high. And the effect of the continuous charge characteristic in a high voltage environment increases. The content is more preferably 0.3% by mass or more, and particularly preferably 0.6% by mass or more. Moreover, the upper limit is more preferably 3% by mass or less, further preferably 2.2% by mass or less, and particularly preferably 1.7% by mass or less.
　本発明の非水電解液においては、一般式（Ｉ）で表される化合物と併用する添加剤として、フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を含有する。これらの中では、フッ素原子含有環状カーボネートがより好ましい。 In the nonaqueous electrolytic solution of the present invention, the additive used in combination with the compound represented by the general formula (I) contains at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate. To do. In these, a fluorine atom containing cyclic carbonate is more preferable.
　フッ素原子含有環状カーボネートとしては、４－フルオロ－１，３－ジオキソラン－２－オン（ＦＥＣ）、トランス又はシス－４，５－ジフルオロ－１，３－ジオキソラン－２－オン（以下、両者を総称して「ＤＦＥＣ」という）等からなる群より選ばれる１種又は２種以上が挙げられ、４－フルオロ－１，３－ジオキソラン－２－オンがより好ましい。 Fluorine atom-containing cyclic carbonates include 4-fluoro-1,3-dioxolan-2-one (FEC), trans or cis-4,5-difluoro-1,3-dioxolan-2-one (hereinafter collectively referred to as both) One or more selected from the group consisting of “DFEC” and the like, and 4-fluoro-1,3-dioxolan-2-one is more preferable.
　不飽和結合含有環状カーボネートとしては、ビニレンカーボネート（ＶＣ）、ビニルエチレンカーボネート（ＶＥＣ）、及び４－エチニル－１，３－ジオキソラン－２－オン（ＥＥＣ）等の炭素－炭素二重結合、炭素－炭素三重結合を有する環状カーボネートからなる群より選ばれる１種又は２種以上が挙げられ、ビニレンカーボネート及び４－エチニル－１，３－ジオキソラン－２－オン（ＥＥＣ）がより好ましい。 Examples of the unsaturated bond-containing cyclic carbonate include carbon-carbon double bonds such as vinylene carbonate (VC), vinyl ethylene carbonate (VEC), and 4-ethynyl-1,3-dioxolan-2-one (EEC), carbon- One or two or more types selected from the group consisting of cyclic carbonates having a carbon triple bond may be mentioned, and vinylene carbonate and 4-ethynyl-1,3-dioxolan-2-one (EEC) are more preferable.
　前記フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる化合物は、組み合わせて使用することで、高温かつ高電圧環境下での連続充電特性の改善効果が相乗的に向上するため好ましい。これらフッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる好適な組み合わせとしては、ＶＣとＦＥＣの組合せ、ＦＥＣとＤＦＥＣの組合せ、ＶＣとＤＦＥＣの組合せ、ＶＥＣとＤＦＥＣの組合せ、ＶＣとＥＥＣの組合せ、及びＥＣとＥＥＣの組合せ等が好ましい。前記の組合せの中でも、ＶＣとＦＥＣの組合せ、ＶＣとＤＦＥＣの組合せ、及びＶＥＣとＤＦＥＣの組合せ等がより好ましい。 Since the compound selected from the group consisting of the fluorine atom-containing cyclic carbonate and the unsaturated bond-containing cyclic carbonate is used in combination, the effect of improving the continuous charge property under a high temperature and high voltage environment is synergistically improved. preferable. Suitable combinations selected from the group consisting of these fluorine atom-containing cyclic carbonates and unsaturated bond-containing cyclic carbonates include VC and FEC combinations, FEC and DFEC combinations, VC and DFEC combinations, VEC and DFEC combinations, VC And a combination of EC and EEC and a combination of EC and EEC are preferable. Among the above combinations, a combination of VC and FEC, a combination of VC and DFEC, a combination of VEC and DFEC, and the like are more preferable.
　前記フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種の総含有量は、非水電解液中に０．１～３０質量％が好ましい。該含有量が３０質量％以下であれば、電極上に過度に被膜が形成され電気化学特性が低下するおそれが少なく、また０．１質量％以上であれば被膜の形成が十分であり、高温かつ高電圧環境下での連続充電特性の効果が高まる。
　該含有量は、非水電解液中に０．５質量％以上が好ましく、１質量％以上が更に好ましい。また、その上限は、２５質量％以下が好ましく、１５質量％以下がより好ましく、１０質量％以下が更に好ましく、６質量％以下が更に好ましく、４質量％以下が特に好ましい。 The total content of at least one selected from the group consisting of the fluorine atom-containing cyclic carbonate and the unsaturated bond-containing cyclic carbonate is preferably 0.1 to 30% by mass in the non-aqueous electrolyte. If the content is 30% by mass or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.1% by mass or more, the film is sufficiently formed, and the temperature is high. And the effect of the continuous charge characteristic in a high voltage environment increases.
The content is preferably 0.5% by mass or more, more preferably 1% by mass or more in the nonaqueous electrolytic solution. Further, the upper limit is preferably 25% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, further preferably 6% by mass or less, and particularly preferably 4% by mass or less.
　一般式（Ｉ）で表される化合物と、フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種の化合物の含有量比（質量比）は、一般式（Ｉ）で表される化合物の含有量をＡ質量％、フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種の化合物の含有量をＢ質量％としたときに、Ａ／Ｂが０．０１～３の範囲が好ましい。該含有量比が３以下であれば、電極上に過度に被膜が形成され電気化学特性が低下するおそれが少なく、また０．０１以上であれば被膜の形成が十分であり、高温かつ高電圧環境下での連続充電特性の効果が高まる。該含有量比は、０．０１以上が好ましく、０．０５以上がより好ましく、０．２以上が更に好ましい。また、その上限は、３以下が好ましく、１．８以下がより好ましく、０．６以下の場合は一段と高温かつ高電圧環境下での連続充電特性が高まるため更に好ましい。 The content ratio (mass ratio) of the compound represented by the general formula (I) and at least one compound selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate is the general formula (I). When the content of the compound represented by A is% by mass and the content of at least one compound selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate is B% by mass, A / B is preferably in the range of 0.01-3. If the content ratio is 3 or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.01 or more, the film is sufficiently formed, and the high temperature and high voltage The effect of continuous charging characteristics in the environment is enhanced. The content ratio is preferably 0.01 or more, more preferably 0.05 or more, and still more preferably 0.2 or more. Further, the upper limit is preferably 3 or less, more preferably 1.8 or less, and the case where the upper limit is 0.6 or less is more preferable because continuous charging characteristics at a higher temperature and a high voltage environment are further improved.
〔非水溶媒〕
　本発明の非水電解液に使用される非水溶媒としては、環状カーボネート（但し、非水溶媒としては、フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートを除く。以下同じ。）、鎖状エステル、ラクトン、エーテル、及びアミドからなる群より選ばれる１種又は２種以上が好適に挙げられる。高温かつ高電圧環境下での連続充電特性を相乗的に向上させるため、環状カーボネートと鎖状エステルの両方が含まれることがもっとも好ましい。
　なお、「鎖状エステル」なる用語は、鎖状カーボネート及び鎖状カルボン酸エステルを含む概念として用いる。 [Nonaqueous solvent]
As the non-aqueous solvent used in the non-aqueous electrolyte of the present invention, a cyclic carbonate (however, the non-aqueous solvent excludes a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate; the same shall apply hereinafter), a chain form. One type or two or more types selected from the group consisting of esters, lactones, ethers and amides are preferred. In order to synergistically improve the continuous charge characteristics in a high temperature and high voltage environment, it is most preferable that both a cyclic carbonate and a chain ester are included.
The term “chain ester” is used as a concept including a chain carbonate and a chain carboxylic acid ester.
（環状カーボネート）
　環状カーボネートとしては、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、１，２－ブチレンカーボネート、及び２，３－ブチレンカーボネートからなる群より選ばれる１種又は２種以上が挙げられ、エチレンカーボネート、プロピレンカーボネートからなる群より選ばれる１種又は２種がより好適である。 (Cyclic carbonate)
Examples of the cyclic carbonate include one or more selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, and 2,3-butylene carbonate. One or two selected from the group consisting of propylene carbonate are more preferable.
（鎖状エステル）
　鎖状エステルとしては、メチルエチルカーボネート（ＭＥＣ）、メチルプロピルカーボネート（ＭＰＣ）、メチルイソプロピルカーボネート（ＭＩＰＣ）、メチルブチルカーボネート、及びエチルプロピルカーボネートからなる群より選ばれる１種又は２種以上の非対称鎖状カーボネート、ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、ジプロピルカーボネート、及びジブチルカーボネートからなる群より選ばれる１種又は２種以上の対称鎖状カーボネート、ピバリン酸メチル、ピバリン酸エチル、ピバリン酸プロピル等のピバリン酸エステル、プロピオン酸メチル（ＭＰ）、プロピオン酸エチル（ＥＰ）、プロピオン酸プロピル（ＰＰ）、酢酸メチル（ＭＡ）、酢酸エチル（ＥＡ）、酢酸プロピル（ＰＡ）、及び酢酸ブチルからなる群より選ばれる１種又は２種以上の鎖状カルボン酸エステルが好適に挙げられる。 (Chain ester)
The chain ester may be one or more asymmetric chains selected from the group consisting of methyl ethyl carbonate (MEC), methyl propyl carbonate (MPC), methyl isopropyl carbonate (MIPC), methyl butyl carbonate, and ethyl propyl carbonate. One or more symmetrical linear carbonates selected from the group consisting of linear carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, and dibutyl carbonate, methyl pivalate, ethyl pivalate, pivalic acid Pivalate esters such as propyl, methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), and vinegar One or more chain carboxylate selected from the group consisting of butyl suitably.
　前記鎖状エステルの中でも、ジメチルカーボネート、メチルエチルカーボネート、ジエチルカーボネート、酢酸プロピル（ＰＡ）、酢酸ブチル、プロピオン酸メチル（ＭＰ）、プロピオン酸エチル（ＥＰ）、プロピオン酸プロピル（ＰＰ）、及びピバリン酸メチルからなる群より選ばれる分子量９０以上１２０以下の鎖状エステルが好ましい。 Among the chain esters, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propyl acetate (PA), butyl acetate, methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), and pivalic acid A chain ester having a molecular weight of 90 or more and 120 or less selected from the group consisting of methyl is preferable.
　鎖状エステルとして鎖状カーボネートを用いる場合は、２種以上を用いることが好ましい。さらに対称鎖状カーボネートと非対称鎖状カーボネートの両方が含まれるとより好ましく、対称鎖状カーボネートの含有量が非対称鎖状カーボネートより多く含まれると更に好ましい。 When using a chain carbonate as the chain ester, it is preferable to use two or more. Further, it is more preferable that both a symmetric chain carbonate and an asymmetric chain carbonate are contained, and it is further more preferable that the content of the symmetric chain carbonate is more than that of the asymmetric chain carbonate.
　鎖状カーボネート中に対称鎖状カーボネートが占める体積の割合は、５１体積％以上が好ましく、５５体積％以上がより好ましい。その上限としては、９５体積％以下が好ましく、８５体積％以下がより好ましい。対称鎖状カーボネートにジメチルカーボネートが含まれると特に好ましい。また、非対称鎖状カーボネートはメチル基を有するとより好ましく、メチルエチルカーボネートが特に好ましい。上記の場合に一段と高温かつ高電圧環境下での連続充電特性が向上するので好ましい。 The proportion of the volume occupied by the symmetrical linear carbonate in the linear carbonate is preferably 51% by volume or more, and more preferably 55% by volume or more. As the upper limit, 95 volume% or less is preferable and 85 volume% or less is more preferable. It is particularly preferred that the symmetric chain carbonate contains dimethyl carbonate. The asymmetric chain carbonate preferably has a methyl group, and methyl ethyl carbonate is particularly preferable. In the above case, continuous charging characteristics at a higher temperature and a higher voltage environment are improved, which is preferable.
　また、鎖状エステルとして、酢酸プロピル、酢酸ブチル、プロピオン酸メチル、プロピオン酸エチル（ＥＰ）、プロピオン酸プロピル（ＰＰ）、及びピバリン酸メチルからなる群より選ばれる１種以上含むとより好ましい。鎖状カルボン酸エステルを用いる場合には、鎖状エステルの全体積に占める割合が１～１００体積％であることが好ましい。上記の場合に最も高温かつ高電圧環境下での連続充電特性が向上するので好ましい。該含有量は鎖状エステル全体に対して７体積％以上がより好ましく、５７体積％以上が更に好ましく、鎖状カルボン酸エステルのみを用いることが特に好ましい。 It is more preferable that the chain ester contains at least one selected from the group consisting of propyl acetate, butyl acetate, methyl propionate, ethyl propionate (EP), propyl propionate (PP), and methyl pivalate. When a chain carboxylic acid ester is used, the ratio of the chain ester to the total volume is preferably 1 to 100% by volume. The above case is preferable because continuous charging characteristics under the highest temperature and high voltage environment are improved. The content is more preferably 7% by volume or more, further preferably 57% by volume or more, and particularly preferably only the chain carboxylic acid ester is used with respect to the entire chain ester.
　鎖状エステルの含有量は、特に制限されないが、非水溶媒の総体積に対して、６０～９０体積％の範囲で用いるのが好ましい。該含有量が６０体積％以上であれば非水電解液の粘度が高くなりすぎず、９０体積％以下であれば非水電解液の電気伝導度が低下して電気化学特性が低下するおそれが少ないので上記範囲であることが好ましい。
　環状カーボネートと鎖状エステルの割合は、高温かつ高電圧環境下での連続充電特性の観点から、環状カーボネート：鎖状エステル（体積比）が１０：９０～４５：５５が好ましく、１５：８５～４０：６０がより好ましく、２０：８０～３５：６５が更に好ましい。 The content of the chain ester is not particularly limited, but it is preferably used in the range of 60 to 90% by volume with respect to the total volume of the nonaqueous solvent. If the content is 60% by volume or more, the viscosity of the non-aqueous electrolyte does not become too high, and if it is 90% by volume or less, the electrical conductivity of the non-aqueous electrolyte may decrease and the electrochemical characteristics may decrease. Since it is few, it is preferable that it is the said range.
The ratio between the cyclic carbonate and the chain ester is preferably 10:90 to 45:55, and preferably 15:85 to cyclic carbonate: chain ester (volume ratio) from the viewpoint of continuous charge characteristics under a high temperature and high voltage environment. 40:60 is more preferable, and 20:80 to 35:65 is more preferable.
（その他の非水溶媒）
　本発明の非水電解液においては、上記以外のその他の非水溶媒を用いることができる。
　その他の非水溶媒としては、テトラヒドロフラン、２－メチルテトラヒドロフラン、及び１，４－ジオキサン等の環状エーテル、１，２－ジメトキシエタン、１，２－ジエトキシエタン、及び１，２－ジブトキシエタン等の鎖状エーテル、ジメチルホルムアミド等のアミド、スルホラン等のスルホン、及びγ－ブチロラクトン（ＧＢＬ）もしくはγ－バレロラクトン、α－アンゲリカラクトン等のラクトンからなる群より選ばれる１種又は２種以上が好適に挙げられる。 (Other non-aqueous solvents)
In the nonaqueous electrolytic solution of the present invention, other nonaqueous solvents other than those described above can be used.
Other non-aqueous solvents include cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, and 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, and the like Preferred is one or more selected from the group consisting of a chain ether, amides such as dimethylformamide, sulfones such as sulfolane, and lactones such as γ-butyrolactone (GBL) or γ-valerolactone, α-angelicalactone It is mentioned in.
　上記その他の非水溶媒は、通常、適切な物性を達成するために、混合して使用される。その組合せは、例えば、環状カーボネートと鎖状エステルとラクトンとの組合せ又は環状カーボネートと鎖状エステルとエーテルとの組合せ等が好適に挙げられ、環状カーボネートと鎖状エステルとラクトンとの組合せがより好ましく、ラクトンの中でもγ－ブチロラクトン（ＧＢＬ）を用いると更に好ましい。
　その他の非水溶媒の含有量は、非水溶媒の総体積に対して、通常１％以上、好ましくは２％以上であり、また通常４０％以下、好ましくは３０％以下、より好ましくは２０％以下である。 The other non-aqueous solvents are usually used as a mixture in order to achieve appropriate physical properties. As the combination, for example, a combination of a cyclic carbonate, a chain ester, and a lactone, or a combination of a cyclic carbonate, a chain ester, and an ether is preferably exemplified, and a combination of a cyclic carbonate, a chain ester, and a lactone is more preferable. Of these lactones, γ-butyrolactone (GBL) is more preferred.
The content of the other nonaqueous solvent is usually 1% or more, preferably 2% or more, and usually 40% or less, preferably 30% or less, more preferably 20%, based on the total volume of the nonaqueous solvent. It is as follows.
（その他の添加剤）
　本発明においては、一段と高温かつ高電圧環境下での連続充電特性を向上させる目的で、非水電解液中にさらにその他の添加剤を加えることが好ましい。
　その他の添加剤の具体例としては、以下の（Ａ）～（Ｈ）の化合物が好適に挙げられる。 (Other additives)
In the present invention, it is preferable to add other additives to the non-aqueous electrolyte for the purpose of improving the continuous charge characteristics at a higher temperature and a higher voltage environment.
Specific examples of other additives include the following compounds (A) to (H).
　（Ａ）スクシノニトリル、グルタロニトリル、アジポニトリル、１，３，５－ヘキサントリカルボニトリル、１，３，６－ヘキサントリカルボニトリル、１，２，３－プロパントリカルボニトリル、１，３，５－ペンタントリカルボニトリル、ピメロニトリル、スベロニトリル、及びセバコニトリル等のＣＮ基とＣＮ基の間の炭素鎖が２以上の多価ニトリル化合物。 (A) Succinonitrile, glutaronitrile, adiponitrile, 1,3,5-hexanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1,3, Multivalent nitrile compounds having two or more carbon chains between the CN group and the CN group, such as 5-pentanetricarbonitrile, pimelonitrile, suberonitrile, and sebacononitrile.
　（Ｂ）シクロヘキシルベンゼン、フルオロシクロヘキシルベンゼン化合物（１－フルオロ－２－シクロヘキシルベンゼン、１－フルオロ－３－シクロヘキシルベンゼン、１－フルオロ－４－シクロヘキシルベンゼン）、ｔｅｒｔ－ブチルベンゼン、ｔｅｒｔ－アミルベンゼン、１－フルオロ－４－ｔｅｒｔ－ブチルベンゼン等の分枝アルキル基を有する芳香族化合物や、ビフェニル、ターフェニル（ｏ－、ｍ－、ｐ－体）、ジフェニルエーテル、フルオロベンゼン、ジフルオロベンゼン（ｏ－、ｍ－、ｐ－体）、アニソール、２，４－ジフルオロアニソール、ターフェニルの部分水素化物（１，２－ジシクロヘキシルベンゼン、２－フェニルビシクロヘキシル、１，２－ジフェニルシクロヘキサン、ｏ－シクロヘキシルビフェニル）等の芳香族化合物。 (B) cyclohexylbenzene, fluorocyclohexylbenzene compound (1-fluoro-2-cyclohexylbenzene, 1-fluoro-3-cyclohexylbenzene, 1-fluoro-4-cyclohexylbenzene), tert-butylbenzene, tert-amylbenzene, 1 Aromatic compounds having a branched alkyl group such as -fluoro-4-tert-butylbenzene, biphenyl, terphenyl (o-, m-, p-isomer), diphenyl ether, fluorobenzene, difluorobenzene (o-, m -, P-form), anisole, 2,4-difluoroanisole, terphenyl hydrides (1,2-dicyclohexylbenzene, 2-phenylbicyclohexyl, 1,2-diphenylcyclohexane, o-cyclohexylbiphenyl), etc. Good Family compound.
　（Ｃ）メチルイソシアネート、エチルイソシアネート、ブチルイソシアネート、フェニルイソシアネート、テトラメチレンジイソシアネート、ヘキサメチレンジイソシアネート、オクタメチレンジイソシアネート、１，４－フェニレンジイソシアネート、２－イソシアナトエチル　アクリレート、及び２－イソシアナトエチル　メタクリレートからなる群より選ばれる１種又は２種以上のイソシアネート化合物。 (C) Consists of methyl isocyanate, ethyl isocyanate, butyl isocyanate, phenyl isocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 1,4-phenylene diisocyanate, 2-isocyanatoethyl acrylate, and 2-isocyanatoethyl methacrylate. One or more isocyanate compounds selected from the group.
　（Ｄ）２－プロピニル　メチル　カーボネート、酢酸　２－プロピニル、ギ酸　２－プロピニル、メタクリル酸　２－プロピニル、メタンスルホン酸　２－プロピニル、ビニルスルホン酸　２－プロピニル、２－（メタンスルホニルオキシ）プロピオン酸２－プロピニル、ジ（２－プロピニル）オギザレート、メチル　２－プロピニルオギザレート、エチル　２－プロピニルオギザレート、グルタル酸　ジ（２－プロピニル）、２－ブチン－１，４－ジイル　ジメタンスルホネート、２－ブチン－１，４－ジイル　ジホルメート、及び２，４－ヘキサジイン－１，６－ジイル　ジメタンスルホネートからなる群より選ばれる１種又は２種以上の三重結合含有化合物。 (D) 2-propynyl methyl carbonate, acetic acid 2-propynyl, formic acid 2-propynyl, methacrylic acid 2-propynyl, methanesulfonic acid 2-propynyl, vinyl sulfonic acid 2-propynyl, 2- (methanesulfonyloxy) propionic acid 2- Propynyl, di (2-propynyl) oxalate, methyl 2-propynyl oxalate, ethyl 2-propynyl oxalate, glutaric acid di (2-propynyl), 2-butyne-1,4-diyl dimethanesulfonate, 2- One or more triple bond-containing compounds selected from the group consisting of butyne-1,4-diyl diformate and 2,4-hexadiyne-1,6-diyl dimethanesulfonate.
　（Ｅ）１，３－プロパンスルトン、１，３－ブタンスルトン、２，４－ブタンスルトン、１，４－ブタンスルトン、１，３－プロペンスルトン、２，２－ジオキシド－１，２－オキサチオラン－４－イル　アセテート、及び５，５－ジメチル－１，２－オキサチオラン－４－オン　２，２－ジオキシド等のスルトン、エチレンサルファイト、ヘキサヒドロベンゾ［１，３，２］ジオキサチオラン－２－オキシド（１，２－シクロヘキサンジオールサイクリックサルファイトともいう）、及び５－ビニル－ヘキサヒドロ－１，３，２－ベンゾジオキサチオール－２－オキシド等の環状サルファイト、環状サルフェート、ブタン－２，３－ジイル　ジメタンスルホネート、ブタン－１，４－ジイル　ジメタンスルホネート、又はメチレンメタンジスルホネート等のスルホン酸エステル、ジビニルスルホン、１，２－ビス（ビニルスルホニル）エタン、及びビス（２－ビニルスルホニルエチル）エーテル等のビニルスルホン化合物からなる群より選ばれる１種又は２種以上のＳ＝Ｏ基を含む非リチウム化合物。 (E) 1,3-propane sultone, 1,3-butane sultone, 2,4-butane sultone, 1,4-butane sultone, 1,3-propene sultone, 2,2-dioxide-1,2-oxathiolan-4-yl Acetate, sultone such as 5,5-dimethyl-1,2-oxathiolane-4-one 2,2-dioxide, ethylene sulfite, hexahydrobenzo [1,3,2] dioxathiolane-2-oxide (1,2 -Cyclohexanediol cyclic sulfite) and cyclic sulfites such as 5-vinyl-hexahydro-1,3,2-benzodioxathiol-2-oxide, cyclic sulfate, butane-2,3-diyl dimethane Sulfonate, butane-1,4-diyl dimethanesulfonate, or methylenemethane One or more S selected from the group consisting of sulfonic acid esters such as sulfonate, divinyl sulfone, 1,2-bis (vinylsulfonyl) ethane, and vinylsulfone compounds such as bis (2-vinylsulfonylethyl) ether = A non-lithium compound containing an O group.
　（Ｆ）１，３－ジオキソラン、１，３－ジオキサン、５，５－ジメチル－１，３－ジオキサン、５－エチル－５－メチル－１，３－ジオキサン、１，３，５－トリオキサン等の環状アセタール化合物。 (F) 1,3-dioxolane, 1,3-dioxane, 5,5-dimethyl-1,3-dioxane, 5-ethyl-5-methyl-1,3-dioxane, 1,3,5-trioxane, etc. Cyclic acetal compound.
　（Ｇ）リン酸トリメチル、リン酸トリブチル、及びリン酸トリオクチル、リン酸トリス（２，２，２－トリフルオロエチル）、リン酸ビス（２，２，２－トリフルオロエチル）メチル、リン酸ビス（２，２，２－トリフルオロエチル）エチル、リン酸ビス（２，２，２－トリフルオロエチル）２，２－ジフルオロエチル、リン酸ビス（２，２，２－トリフルオロエチル）２，２，３，３－テトラフルオロプロピル、リン酸ビス（２，２－ジフルオロエチル）２，２，２－トリフルオロエチル、リン酸ビス（２，２，３，３－テトラフルオロプロピル）２，２，２－トリフルオロエチル及びリン酸（２，２，２－トリフルオロエチル）（２，２，３，３－テトラフルオロプロピル）メチル、リン酸トリス（１，１，１，３，３，３－ヘキサフルオロプロパン－２－イル）、メチレンビスホスホン酸メチル、メチレンビスホスホン酸エチル、エチレンビスホスホン酸メチル、エチレンビスホスホン酸エチル、ブチレンビスホスホン酸メチル、ブチレンビスホスホン酸エチル、メチル　２－（ジメチルホスホリル）アセテート、エチル　２－（ジメチルホスホリル）アセテート、メチル　２－（ジエチルホスホリル）アセテート、エチル　２－（ジエチルホスホリル）アセテート、２－プロピニル　２－（ジメチルホスホリル）アセテート、２－プロピニル　２－（ジエチルホスホリル）アセテート、メチル　２－（ジメトキシホスホリル）アセテート、エチル　２－（ジメトキシホスホリル）アセテート、メチル　２－（ジエトキシホスホリル）アセテート、エチル　２－（ジエトキシホスホリル）アセテート、２－プロピニル　２－（ジメトキシホスホリル）アセテート、２－プロピニル　２－（ジエトキシホスホリル）アセテート、及びピロリン酸メチル、ピロリン酸エチルからなる群より選ばれる１種又は２種以上のリン含有化合物。 (G) Trimethyl phosphate, tributyl phosphate, trioctyl phosphate, tris (2,2,2-trifluoroethyl phosphate), bis (2,2,2-trifluoroethyl) methyl phosphate, bis phosphate (2,2,2-trifluoroethyl) ethyl, bis (2,2,2-trifluoroethyl) phosphate 2,2-difluoroethyl, bis (2,2,2-trifluoroethyl) phosphate 2, 2,3,3-tetrafluoropropyl, bis (2,2-difluoroethyl) phosphate 2,2,2-trifluoroethyl, bis (2,2,3,3-tetrafluoropropyl) phosphate 2,2 , 2-trifluoroethyl and phosphoric acid (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoropropyl) methyl, phosphoric acid tris (1,1,1,3,3,3 -Hexaph Olopropan-2-yl), methyl methylene bisphosphonate, ethyl methylene bisphosphonate, methyl ethylene bisphosphonate, ethyl ethylene bisphosphonate, methyl butylene bisphosphonate, ethyl butylene bisphosphonate, methyl 2- (dimethylphosphoryl) acetate, ethyl 2- ( Dimethylphosphoryl) acetate, methyl 2- (diethylphosphoryl) acetate, ethyl 2- (diethylphosphoryl) acetate, 2-propynyl 2- (dimethylphosphoryl) acetate, 2-propynyl 2- (diethylphosphoryl) acetate, methyl 2- (dimethoxy) Phosphoryl) acetate, ethyl 2- (dimethoxyphosphoryl) acetate, methyl 2- (diethoxyphosphoryl) acetate, ethyl 2- (dietoxy) Phosphoryl) acetate, 2-propynyl 2- (dimethoxyphosphoryl) acetate, 2-propynyl 2- (diethoxyphosphoryl) acetate, and one or more types of phosphorus selected from the group consisting of methyl pyrophosphate and ethyl pyrophosphate Compound.
　（Ｈ）無水酢酸、無水プロピオン酸等の鎖状のカルボン酸無水物、無水コハク酸、無水マレイン酸、３－アリル無水コハク酸、無水グルタル酸、無水イタコン酸、及び３－スルホ－プロピオン酸無水物等の環状酸無水物。 (H) Chain carboxylic anhydrides such as acetic anhydride and propionic anhydride, succinic anhydride, maleic anhydride, 3-allyl succinic anhydride, glutaric anhydride, itaconic anhydride, and 3-sulfo-propionic anhydride Cyclic acid anhydrides such as products.
　（Ａ）多価ニトリル化合物の中では、－ＣＮ基と－ＣＮ基の間の炭素鎖が４以上のアジポニトリル、ピメロニトリル、スベロニトリル、及びセバコニトリルからなる群より選ばれる１種以上が更に好ましい。 (A) Among the polyvalent nitrile compounds, at least one selected from the group consisting of adiponitrile, pimelonitrile, suberonitrile, and sebaconitrile having 4 or more carbon chains between the —CN group and the —CN group is more preferable.
　（Ｂ）芳香族化合物の中では、ビフェニル、ターフェニル（ｏ－、ｍ－、ｐ－体）、フルオロベンゼン、シクロヘキシルベンゼン、ｔｅｒｔ－ブチルベンゼン、及びｔｅｒｔ－アミルベンゼンからなる群より選ばれる１種又は２種以上がより好ましく、ビフェニル、ｏ－ターフェニル、フルオロベンゼン、シクロヘキシルベンゼン、及びｔｅｒｔ－アミルベンゼンからなる群より選ばれる１種又は２種以上が特に好ましい。 (B) Among aromatic compounds, one selected from the group consisting of biphenyl, terphenyl (o-, m-, p-isomer), fluorobenzene, cyclohexylbenzene, tert-butylbenzene, and tert-amylbenzene Alternatively, two or more are more preferable, and one or more selected from the group consisting of biphenyl, o-terphenyl, fluorobenzene, cyclohexylbenzene, and tert-amylbenzene are particularly preferable.
　（Ｃ）イソシアネート化合物の中では、ヘキサメチレンジイソシアネート、オクタメチレンジイソシアネート、２－イソシアナトエチル　アクリレート、及び２－イソシアナトエチル　メタクリレートからなる群より選ばれる１種又は２種以上がより好ましい。 (C) Among the isocyanate compounds, one or more selected from the group consisting of hexamethylene diisocyanate, octamethylene diisocyanate, 2-isocyanatoethyl acrylate, and 2-isocyanatoethyl methacrylate are more preferable.
　（Ｄ）三重結合含有化合物としては、２－プロピニル－メチルカーボネート、メタクリル酸－２－プロピニル、メタンスルホン酸－２－プロピニル、ビニルスルホン酸－２－プロピニル、２－（メタンスルホニルオキシ）プロピオン酸－２－プロピニル、ジ（２－プロピニル）オギザレート、メチル－２－プロピニルオギザレート、エチル－２－プロピニルオギザレート、及び２－ブチン－１，４－ジイル－ジメタンスルホネートからなる群より選ばれる１種又は２種以上が好ましく、メタンスルホン酸－２－プロピニル、ビニルスルホン酸－２－プロピニル、２－（メタンスルホニルオキシ）プロピオン酸－２－プロピニル、ジ（２－プロピニル）オギザレート、及び２－ブチン－１，４－ジイル　ジメタンスルホネートからなる群より選ばれる１種又は２種以上が更に好ましい。 (D) Triple bond-containing compounds include 2-propynyl-methyl carbonate, 2-propynyl methacrylate, 2-propynyl methanesulfonate, 2-propynyl vinylsulfonate, 2- (methanesulfonyloxy) propionic acid Selected from the group consisting of 2-propynyl, di (2-propynyl) oxalate, methyl-2-propynyl oxalate, ethyl-2-propynyl oxalate, and 2-butyne-1,4-diyl-dimethanesulfonate 1 type or 2 types or more are preferable, and 2-propynyl methanesulfonate, 2-propynyl vinylsulfonate, 2-propynyl 2- (methanesulfonyloxy) propionate, di (2-propynyl) oxalate, and 2- Butyne-1,4-diyl from the group consisting of dimethanesulfonate One or more barrel more preferred.
　（Ｅ）スルトン、環状サルファイト、環状サルフェート、スルホン酸エステル、及びビニルスルホンからなる群より選ばれる環状又は鎖状のＳ＝Ｏ基を含む非リチウム化合物（但し、三重結合含有化合物、及び前記一般式のいずれかで表される特定の化合物は含まない）を用いることが好ましい。 (E) a non-lithium compound containing a cyclic or chain S═O group selected from the group consisting of sultone, cyclic sulfite, cyclic sulfate, sulfonic acid ester, and vinyl sulfone (however, a triple bond-containing compound, It is preferable to use a specific compound represented by any of the formulas).
　前記環状のＳ＝Ｏ基含有化合物としては、１，３－プロパンスルトン、１，３－ブタンスルトン、１，４－ブタンスルトン、２，４－ブタンスルトン、１，３－プロペンスルトン、２，２－ジオキシド－１，２－オキサチオラン－４－イル－アセテート、５，５－ジメチル－１，２－オキサチオラン－４－オン－２，２－ジオキシド、メチレンメタンジスルホネート、エチレンサルファイト、エチレンサルフェート、及び４－（メチルスルホニルメチル）－１，３，２－ジオキサチオラン－２－オキシドからなる群より選ばれる１種又は２種以上が好適に挙げられる。 Examples of the cyclic S═O group-containing compound include 1,3-propane sultone, 1,3-butane sultone, 1,4-butane sultone, 2,4-butane sultone, 1,3-propene sultone, 2,2-dioxide- 1,2-oxathiolan-4-yl-acetate, 5,5-dimethyl-1,2-oxathiolane-4-one-2,2-dioxide, methylenemethane disulfonate, ethylene sulfite, ethylene sulfate, and 4- ( Preferable examples include one or more selected from the group consisting of (methylsulfonylmethyl) -1,3,2-dioxathiolane-2-oxide.
　また、鎖状のＳ＝Ｏ基含有化合物としては、ブタン－２，３－ジイル－ジメタンスルホネート、ブタン－１，４－ジイル－ジメタンスルホネート、ジメチルメタンジスルホネート、ペンタフルオロフェニルメタンスルホネート、ジビニルスルホン、及びビス（２－ビニルスルホニルエチル）エーテルからなる群より選ばれる１種又は２種以上が好適に挙げられる。
　前記環状又は鎖状のＳ＝Ｏ基含有化合物の中でも、１，３－プロパンスルトン、１，４－ブタンスルトン、２，４－ブタンスルトン、２，２－ジオキシド－１，２－オキサチオラン－４－イル－アセテート、エチレンサルフェート、ペンタフルオロフェニルメタンスルホネート、及びジビニルスルホンからなる群より選ばれる１種又は２種以上が更に好ましい。 Examples of the chain-containing S═O group-containing compound include butane-2,3-diyl-dimethanesulfonate, butane-1,4-diyl-dimethanesulfonate, dimethylmethane disulfonate, pentafluorophenylmethanesulfonate, divinyl One or more kinds selected from the group consisting of sulfone and bis (2-vinylsulfonylethyl) ether are preferred.
Among the cyclic or chain-containing S═O group-containing compounds, 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, 2,2-dioxide-1,2-oxathiolan-4-yl- One or more selected from the group consisting of acetate, ethylene sulfate, pentafluorophenyl methanesulfonate, and divinylsulfone are more preferable.
　（Ｆ）環状アセタール化合物としては、１，３－ジオキソラン、５，５－ジメチル－１，３－ジオキサン、及び５－エチル－５－メチル－１，３－ジオキサンが好ましく、１，３－ジオキサン及び５，５－ジメチル－１，３－ジオキサンがより好ましい。 (F) As the cyclic acetal compound, 1,3-dioxolane, 5,5-dimethyl-1,3-dioxane, and 5-ethyl-5-methyl-1,3-dioxane are preferable, and 1,3-dioxane and More preferred is 5,5-dimethyl-1,3-dioxane.
　（Ｇ）リン含有化合物としては、リン酸トリス（２，２，２－トリフルオロエチル）、リン酸トリス（１，１，１，３，３，３－ヘキサフルオロプロパン－２－イル）、メチル－２－（ジメチルホスホリル）アセテート、エチル－２－（ジメチルホスホリル）アセテート、メチル－２－（ジエチルホスホリル）アセテート、エチル－２－（ジエチルホスホリル）アセテート、２－プロピニル－２－（ジメチルホスホリル）アセテート、２－プロピニル－２－（ジエチルホスホリル）アセテート、メチル－２－（ジメトキシホスホリル）アセテート、エチル－２－（ジメトキシホスホリル）アセテート、メチル－２－（ジエトキシホスホリル）アセテート、エチル－２－（ジエトキシホスホリル）アセテート、２－プロピニル－２－（ジメトキシホスホリル）アセテート、及び２－プロピニル－２－（ジエトキシホスホリル）アセテートが好ましく、リン酸トリス（２，２，２－トリフルオロエチル）、リン酸トリス（１，１，１，３，３，３－ヘキサフルオロプロパン－２－イル）、エチル－２－（ジエチルホスホリル）アセテート、２－プロピニル－２－（ジメチルホスホリル）アセテート、２－プロピニル－２－（ジエチルホスホリル）アセテート、エチル－２－（ジエトキシホスホリル）アセテート、２－プロピニル－２－（ジメトキシホスホリル）アセテート、及び２－プロピニル－２－（ジエトキシホスホリル）アセテートが更に好ましい。 (G) Phosphorus-containing compounds include tris phosphate (2,2,2-trifluoroethyl), tris phosphate (1,1,1,3,3,3-hexafluoropropan-2-yl), methyl -2- (dimethylphosphoryl) acetate, ethyl-2- (dimethylphosphoryl) acetate, methyl-2- (diethylphosphoryl) acetate, ethyl-2- (diethylphosphoryl) acetate, 2-propynyl-2- (dimethylphosphoryl) acetate 2-propynyl-2- (diethylphosphoryl) acetate, methyl-2- (dimethoxyphosphoryl) acetate, ethyl-2- (dimethoxyphosphoryl) acetate, methyl-2- (diethoxyphosphoryl) acetate, ethyl-2- (di Ethoxyphosphoryl) acetate, 2-propynyl-2- (dimetho Cyphosphoryl) acetate and 2-propynyl-2- (diethoxyphosphoryl) acetate are preferred, and tris phosphate (2,2,2-trifluoroethyl), tris phosphate (1,1,1,3,3,3) -Hexafluoropropan-2-yl), ethyl-2- (diethylphosphoryl) acetate, 2-propynyl-2- (dimethylphosphoryl) acetate, 2-propynyl-2- (diethylphosphoryl) acetate, ethyl-2- (di-) More preferred are ethoxyphosphoryl) acetate, 2-propynyl-2- (dimethoxyphosphoryl) acetate, and 2-propynyl-2- (diethoxyphosphoryl) acetate.
　（Ｈ）環状酸無水物としては、無水コハク酸、無水マレイン酸、及び３－アリル無水コハク酸が好ましく、無水コハク酸及び３－アリル無水コハク酸が更に好ましい。 (H) As the cyclic acid anhydride, succinic anhydride, maleic anhydride, and 3-allyl succinic anhydride are preferable, and succinic anhydride and 3-allyl succinic anhydride are more preferable.
　上記の中でも、（Ａ）多価ニトリル化合物、（Ｄ）三重結合含有化合物、（Ｅ）Ｓ＝Ｏ基を含む非リチウム化合物、及び（Ｆ）環状アセタール化合物からなる群より選ばれる少なくとも１種以上を含むとより一段と高温かつ高電圧環境下での連続充電特性が向上するので好ましい。 Among the above, at least one selected from the group consisting of (A) a polyvalent nitrile compound, (D) a triple bond-containing compound, (E) a non-lithium compound containing an S═O group, and (F) a cyclic acetal compound. It is preferable because the continuous charge characteristics under a higher temperature and higher voltage environment are further improved.
　前記（Ａ）～（Ｈ）の化合物の総含有量は、非水電解液中に０．０１～７質量％が好ましい。この範囲では、被膜が厚くなり過ぎずに十分に形成され、一段と高温かつ高電圧環境下での連続充電特性が高まる。該総含有量は、非水電解液中に０．０５質量％以上がより好ましく、０．１質量％以上が更に好ましく、その上限は、５質量％以下がより好ましく、３質量％以下が更に好ましい。 The total content of the compounds (A) to (H) is preferably 0.01 to 7% by mass in the non-aqueous electrolyte. In this range, the coating film is sufficiently formed without becoming too thick, and the continuous charging characteristics at a higher temperature and a higher voltage environment are further enhanced. The total content is more preferably 0.05% by mass or more, more preferably 0.1% by mass or more in the non-aqueous electrolyte, and the upper limit thereof is more preferably 5% by mass or less, and further preferably 3% by mass or less. preferable.
（電解質塩）
　本発明に使用される電解質塩としては、下記のリチウム塩が好適に挙げられる。
　リチウム塩としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４等の無機リチウム塩、ＬｉＣＦ３ＳＯ３、ＬｉＣ（ＳＯ２ＣＦ３）３、ＬｉＰＦ４（ＣＦ３）２、ＬｉＰＦ３（Ｃ２Ｆ５）３、ＬｉＰＦ３（ＣＦ３）３、ＬｉＰＦ３（ｉｓｏ－Ｃ３Ｆ7）３、ＬｉＰＦ５（ｉｓｏ－Ｃ３Ｆ7）等の鎖状のフッ化アルキル基を含有するリチウム塩が好適に挙げられ、これらの中から選ばれる少なくとも１種のリチウム塩が好適に挙げられ、これらの１種又は２種以上を混合して使用することができる。
　これらの中でも、ＬｉＰＦ６及びＬｉＢＦ４が好ましく、ＬｉＰＦ６を用いることがもっとも好ましい。電解質塩の濃度は、非水電解液中で、通常０．３Ｍ以上が好ましく、０．７Ｍ以上がより好ましく、１．１Ｍ以上が更に好ましい。またその上限は、２．５Ｍ以下が好ましく、２．０Ｍ以下がより好ましく、１．６Ｍ以下が更に好ましい。 (Electrolyte salt)
Preferred examples of the electrolyte salt used in the present invention include the following lithium salts.
Examples of lithium salts include inorganic lithium salts such as LiPF 6 , LiBF 4 and LiClO 4 , LiCF 3 SO 3 , LiC (SO 2 CF 3 ) 3 , LiPF 4 (CF 3 ) 2 , LiPF 3 (C 2 F 5 ) 3. Preferred examples include lithium salts containing a chain-like fluorinated alkyl group, such as LiPF 3 (CF 3 ) 3 , LiPF 3 (iso-C 3 F 7 ) 3 , LiPF 5 (iso-C 3 F 7 ). Favorable examples include at least one lithium salt selected from these, and one or more of these may be used in combination.
Among these, LiPF 6 and LiBF 4 are preferable, and it is most preferable to use LiPF 6 . The concentration of the electrolyte salt is usually preferably 0.3 M or higher, more preferably 0.7 M or higher, and even more preferably 1.1 M or higher in the nonaqueous electrolytic solution. Moreover, the upper limit is preferably 2.5M or less, more preferably 2.0M or less, and still more preferably 1.6M or less.
　また、一段と高温かつ高電圧環境下での連続充電特性を向上させる目的で、非水電解液中にさらに、シュウ酸構造を有するリチウム塩（Ｉ）、リン酸構造を有するリチウム塩（II）、Ｓ＝Ｏ基を有するリチウム塩（III）、及びフッ素原子を有するリチウムイミド塩（IV）からなる群より選ばれる１種以上のリチウム塩を含むことが好ましい。 Further, for the purpose of improving the continuous charge characteristics under a higher temperature and higher voltage environment, the non-aqueous electrolyte further includes a lithium salt (I) having an oxalic acid structure, a lithium salt (II) having a phosphoric acid structure, It is preferable to include at least one lithium salt selected from the group consisting of a lithium salt (III) having an S═O group and a lithium imide salt (IV) having a fluorine atom.
　シュウ酸構造を有するリチウム塩（Ｉ）としては、リチウム　ビス（オキサラト）ボレート（ＬｉＢＯＢ）、リチウム　ジフルオロ（オキサラト）ボレート（ＬｉＤＦＯＢ）、リチウム　テトラフルオロ（オキサラト）ホスフェート（ＬｉＴＦＯＰ）、及びリチウム　ジフルオロビス（オキサラト）ホスフェート（ＬｉＤＦＯＰ）が好適に挙げられ、これらの中でも、ＬｉＢＯＢ、ＬｉＤＦＯＢ、ＬｉＤＦＯＰが好ましい。 Examples of the lithium salt (I) having an oxalic acid structure include lithium bis (oxalato) borate (LiBOB), lithium difluoro (oxalato) borate (LiDFOB), lithium tetrafluoro (oxalato) phosphate (LiTFOP), and lithium difluorobis (oxalato). ) Phosphate (LiDFOP) is preferred, and among these, LiBOB, LiDFOB, and LiDFOP are preferred.
　リン酸構造を有するリチウム塩（II）としては、ジフルオロリン酸リチウム（ＬｉＰＯ２Ｆ２）、フルオロリン酸リチウム（Ｌｉ２ＰＯ３Ｆ）、リチウム　ビス（ジフルオロホスホリル）アミド、リチウム（ジフルオロホスホリル）（フルオロオキシドホスホリル）アミド等のリン酸構造を有するリチウム塩が好適に挙げられ、これらの中でもＬｉＰＯ２Ｆ２、Ｌｉ２ＰＯ３Ｆがより好ましく、ＬｉＰＯ２Ｆ２が更に好ましい。 Examples of the lithium salt (II) having a phosphoric acid structure include lithium difluorophosphate (LiPO 2 F 2 ), lithium fluorophosphate (Li 2 PO 3 F), lithium bis (difluorophosphoryl) amide, lithium (difluorophosphoryl) ( Suitable examples include lithium salts having a phosphoric acid structure such as fluorooxide phosphoryl) amide, among which LiPO 2 F 2 and Li 2 PO 3 F are more preferred, and LiPO 2 F 2 is even more preferred.
　Ｓ＝Ｏ基を有するリチウム塩（III）としては、フルオロ硫酸リチウム（ＦＳＯ３Ｌｉ）、リチウム　メチルサルフェート（ＬＭＳ）、リチウムエチルサルフェート（ＬＥＳ）、リチウム　２，２，２－トリフルオロエチルサルフェート（ＬＦＥＳ）、リチウム　トリフルオロ（（メタンスルホニル）オキシ）ボレート（ＬｉＴＦＭＳＢ）、リチウム　ペンタフルオロ（（メタンスルホニル）オキシ）ホスフェート（ＬｉＰＦＭＳＰ）が好適に挙げられ、これらの中でも、ＬＭＳ、ＬＥＳ、ＦＳＯ３Ｌｉ、ＬＦＥＳ及びＬｉＴＦＭＳＢが好ましく、ＬＭＳ、ＬＥＳが更に好ましい。 Examples of the lithium salt (III) having an S═O group include lithium fluorosulfate (FSO 3 Li), lithium methyl sulfate (LMS), lithium ethyl sulfate (LES), lithium 2,2,2-trifluoroethyl sulfate (LFES). ), Lithium trifluoro ((methanesulfonyl) oxy) borate (LiTFMSB), lithium pentafluoro ((methanesulfonyl) oxy) phosphate (LiPFMSP), and among them, LMS, LES, FSO 3 Li, LFES And LiTFMSB are preferred, and LMS and LES are more preferred.
　本発明の非水電解液において、リチウム塩（Ｉ）、（II）又は（III）のそれぞれの塩の含有量は、非水電解液中に０．００１～０．２Ｍが好ましい。該含有量が０．２Ｍ以下であれば、電極上に過度に被膜が形成され電気化学特性が低下するおそれが少なく、０．００１Ｍ以上であれば高温かつ高電圧環境下での連続充電後の平均放電電圧の低下を抑える効果が十分であり、連続充電後の電池特性の改善効果が高まる。該含有量は、非水電解液中に０．０１Ｍ以上が好ましく、０．０３Ｍ以上がより好ましく、特に好ましくは０．０４Ｍ以上である。その上限は、０．１５Ｍ以下が好ましく、０．１２Ｍ以下がより好ましい。 In the non-aqueous electrolyte of the present invention, the content of each salt of lithium salt (I), (II) or (III) is preferably 0.001 to 0.2 M in the non-aqueous electrolyte. If the content is 0.2 M or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered. If 0.001 M or more, the content after continuous charging in a high temperature and high voltage environment is low. The effect of suppressing the decrease in average discharge voltage is sufficient, and the effect of improving battery characteristics after continuous charging is enhanced. The content is preferably 0.01 M or more, more preferably 0.03 M or more, and particularly preferably 0.04 M or more in the nonaqueous electrolytic solution. The upper limit is preferably 0.15M or less, and more preferably 0.12M or less.
　フッ素原子を有するリチウムイミド塩（IV）としては、（ＣＦ２）２（ＳＯ２）２ＮＬｉ、（ＣＦ２）３（ＳＯ２）２ＮＬｉ、ＬｉＮ（ＳＯ２Ｆ）２（ＬｉＦＳＩ）、ＬｉＮ（ＳＯ２ＣＦ３）２（ＬｉＴＦＳＩ）、及びＬｉＮ（ＳＯ２Ｃ２Ｆ５）２からなる群より選ばれる１種以上が好適に挙げられ、これらの中でも、ＬｉＴＦＳＩ、及びＬｉＦＳＩから選ばれる１種以上がより好ましく、ＬｉＦＳＩが更に好ましい。 As the lithium imide salt (IV) having a fluorine atom, (CF 2 ) 2 (SO 2 ) 2 NLi, (CF 2 ) 3 (SO 2 ) 2 NLi, LiN (SO 2 F) 2 (LiFSI), LiN ( One or more types selected from the group consisting of SO 2 CF 3 ) 2 (LiTFSI) and LiN (SO 2 C 2 F 5 ) 2 are preferably mentioned, and among these, one or more types selected from LiTFSI and LiFSI Is more preferable, and LiFSI is more preferable.
　本発明の非水電解液において、リチウムイミド塩（IV）の含有量は、非水電解液中に０．０１～１Ｍが好ましい。該含有量が１Ｍ以下であれば、電極上に過度に被膜が形成され電気化学特性が低下するおそれが少なく、０．０１Ｍ以上であれば高温かつ高電圧環境下での連続充電後の平均放電電圧の低下を抑える効果が十分であり、連続充電後の電池特性の改善効果が高まる。該含有量は、非水電解液中に０．０３Ｍ以上が好ましく、０．０５Ｍ以上がより好ましく、その上限は、０．９Ｍ以下が好ましく、０．７Ｍ以下がより好ましい。 In the nonaqueous electrolytic solution of the present invention, the content of the lithium imide salt (IV) is preferably 0.01 to 1M in the nonaqueous electrolytic solution. If the content is 1M or less, there is little possibility that the film is excessively formed on the electrode and the electrochemical characteristics are lowered, and if it is 0.01M or more, the average discharge after continuous charging in a high temperature and high voltage environment The effect of suppressing the voltage drop is sufficient, and the effect of improving battery characteristics after continuous charging is enhanced. The content is preferably 0.03M or more, more preferably 0.05M or more in the non-aqueous electrolyte, and the upper limit thereof is preferably 0.9M or less, more preferably 0.7M or less.
〔非水電解液の製造〕
　本発明の非水電解液は、例えば、前記の非水溶媒を混合し、これに前記の電解質塩及び該非水電解液に対して一般式（Ｉ）で表される化合物とフッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を添加することにより得ることができる。
　この際、用いる非水溶媒及び非水電解液に加える化合物は、生産性を著しく低下させない範囲内で、予め精製して、不純物が極力少ないものを用いることが好ましい。 [Production of non-aqueous electrolyte]
The nonaqueous electrolytic solution of the present invention is prepared, for example, by mixing the nonaqueous solvent described above with the electrolyte salt and the compound represented by the general formula (I) with respect to the nonaqueous electrolytic solution and a fluorine atom-containing cyclic carbonate. And at least one selected from the group consisting of unsaturated bond-containing cyclic carbonates.
At this time, it is preferable that the compound added to the non-aqueous solvent and the non-aqueous electrolyte to be used is one that is purified in advance and has as few impurities as possible within a range that does not significantly reduce the productivity.
　本発明の非水電解液は、下記の第１～第４の蓄電デバイスに使用することができ、非水電解質として、液体状のものだけでなくゲル化されているものも使用し得る。更に本発明の非水電解液は固体高分子電解質用としても使用できる。これらの中でも電解質塩にリチウム塩を使用する第１の蓄電デバイス用（即ち、リチウム電池用）又は第４の蓄電デバイス用（即ち、リチウムイオンキャパシタ用）として用いることが好ましく、リチウム電池用として用いることが更に好ましく、リチウム二次電池用として用いることが最も適している。 The nonaqueous electrolytic solution of the present invention can be used in the following first to fourth electric storage devices, and as the nonaqueous electrolyte, not only a liquid but also a gelled one can be used. Furthermore, the non-aqueous electrolyte of the present invention can be used for a solid polymer electrolyte. Among these, it is preferable to use for the 1st electrical storage device which uses lithium salt for electrolyte salt (namely, for lithium batteries) or 4th electrical storage device (namely, for lithium ion capacitors), and it uses for lithium batteries More preferably, it is most suitable to be used for a lithium secondary battery.
〔第１の蓄電デバイス（リチウム電池）〕
　本発明に係る第１の蓄電デバイスであるリチウム電池とは、リチウム一次電池及びリチウム二次電池の総称であり、リチウム二次電池という用語は、いわゆるリチウムイオン二次電池も含む概念として用いる。
　本発明のリチウム電池は、正極、負極及び非水溶媒に電解質塩が溶解されている前記非水電解液からなる。非水電解液以外の正極、負極等の構成部材は特に制限なく使用できる。 [First power storage device (lithium battery)]
The lithium battery, which is the first power storage device according to the present invention, is a generic term for a lithium primary battery and a lithium secondary battery, and the term lithium secondary battery is used as a concept including a so-called lithium ion secondary battery.
The lithium battery of the present invention comprises the nonaqueous electrolyte solution in which an electrolyte salt is dissolved in a positive electrode, a negative electrode, and a nonaqueous solvent. Components other than the non-aqueous electrolyte, such as a positive electrode and a negative electrode, can be used without particular limitation.
（正極活物質）
　例えば、リチウム二次電池用正極活物質としては、コバルト、マンガン、及びニッケルからなる群より選ばれる１種又は２種以上を含有するリチウムとの複合金属酸化物が使用される。これらの正極活物質は、１種単独で用いるか又は２種以上を組み合わせて用いることができる。
　このようなリチウム複合金属酸化物としては、例えば、ＬｉＣｏＯ２、ＬｉＣｏ１－ｘＭｘＯ２（但し、ＭはＳｎ、Ｍｇ、Ｆｅ、Ｔｉ、Ａｌ、Ｚｒ、Ｃｒ、Ｖ、Ｇａ、Ｚｎ、及びＣｕからなる群より選ばれる１種又は２種以上の元素、０．００１≦ｘ≦０．０５）、ＬｉＭｎ２Ｏ４、ＬｉＮｉＯ２、ＬｉＣｏ１－ｘＮｉｘＯ２（０．０１＜ｘ＜１）、ＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２、ＬｉＮｉ０．５Ｍｎ０．３Ｃｏ０．２Ｏ２、ＬｉＮｉ０．８Ｍｎ０．１Ｃｏ０．１Ｏ２、ＬｉＮｉ０．８Ｃｏ０．１５Ａｌ０．０５Ｏ２、Ｌｉ２ＭｎＯ３とＬｉＭＯ２（Ｍは、Ｃｏ、Ｎｉ、Ｍｎ、Ｆｅ等の遷移金属）との固溶体、及びＬｉＮｉ１／２Ｍｎ３／２Ｏ４からなる群より選ばれる１種又は２種以上がより好適である。また、ＬｉＣｏＯ２とＬｉＭｎ２Ｏ４、ＬｉＣｏＯ２とＬｉＮｉＯ２、ＬｉＭｎ２Ｏ４とＬｉＮｉＯ２のように併用してもよい。 (Positive electrode active material)
For example, as a positive electrode active material for a lithium secondary battery, a composite metal oxide with lithium containing one or more selected from the group consisting of cobalt, manganese, and nickel is used. These positive electrode active materials can be used alone or in combination of two or more.
Examples of such a lithium composite metal oxide include LiCoO 2 , LiCo 1-x M x O 2 (where M is Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, and One or more elements selected from the group consisting of Cu, 0.001 ≦ x ≦ 0.05, LiMn 2 O 4 , LiNiO 2 , LiCo 1-x Ni x O 2 (0.01 <x < 1), LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 , LiNi 0 .8 Co 0.15 Al 0.05 O 2 , Li 2 MnO 3 and LiMO 2 (M is a transition metal such as Co, Ni, Mn, and Fe), and LiNi 1/2 Mn 3/2 O one or selected from the group consisting of 4 The above is the more suitable. Moreover, LiCoO 2 and LiMn 2 O 4, LiCoO 2 and LiNiO 2, may be used in combination as LiMn 2 O 4 and LiNiO 2.
　高充電電圧で動作するリチウム複合金属酸化物を使用すると、一般的に、充電時における電解液との反応により高温かつ高電圧環境下での連続充電特性が低下しやすいが、本発明に係るリチウム二次電池ではこれらの電気化学特性の低下を抑制することができる。
　特にＮｉを含む正極活物質を使用すると、一般的に、Ｎｉの触媒作用により正極表面での非水溶媒の分解が起き、電池の抵抗が増加しやすい傾向にある。特に高温かつ高電圧環境下での連続充電特性が低下しやすい傾向にあるが、本発明に係るリチウム二次電池ではこれらの電気化学特性の低下を抑制することができるので好ましい。特に、正極活物質中の全遷移金属元素の原子濃度に対するＮｉの原子濃度の割合が、１０ａｔｏｍｉｃ％を超える正極活物質を用いた場合に上記効果が顕著になるので好ましく、２０ａｔｏｍｉｃ％以上が更に好ましく、３０％以上が特に好ましい。具体的には、ＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２、ＬｉＮｉ０．５Ｍｎ０．３Ｃｏ０．２Ｏ２、ＬｉＮｉ０．８Ｍｎ０．１Ｃｏ０．１Ｏ２、ＬｉＮｉ０．８Ｃｏ０．１５Ａｌ０．０５Ｏ２等からなる群より選ばれる１種以上が好適に挙げられる。 When a lithium composite metal oxide that operates at a high charge voltage is used, the continuous charge characteristics under a high temperature and high voltage environment are likely to deteriorate due to a reaction with the electrolyte during charging. In the secondary battery, it is possible to suppress the deterioration of these electrochemical characteristics.
In particular, when a positive electrode active material containing Ni is used, the nonaqueous solvent is generally decomposed on the surface of the positive electrode due to the catalytic action of Ni, and the battery resistance tends to increase. In particular, the continuous charge characteristics tend to be deteriorated under a high temperature and high voltage environment. However, the lithium secondary battery according to the present invention is preferable because it can suppress a decrease in these electrochemical characteristics. In particular, when a positive electrode active material in which the ratio of the atomic concentration of Ni with respect to the atomic concentration of all transition metal elements in the positive electrode active material exceeds 10 atomic% is used, the above effect is significant, and more preferably 20 atomic% or more. 30% or more is particularly preferable. Specifically, LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 , One or more selected from the group consisting of LiNi 0.8 Co 0.15 Al 0.05 O 2 and the like are preferable.
　更に、正極活物質として、リチウム含有オリビン型リン酸塩を用いることもできる。特に鉄、コバルト、ニッケルおよびマンガンから選ばれる１種以上含むリチウム含有オリビン型リン酸塩が好ましい。その具体例としては、ＬｉＦｅＰＯ４、ＬｉＣｏＰＯ４、ＬｉＮｉＰＯ４、ＬｉＭｎＰＯ４、及びＬｉＦｅ1-ｘＭｎｘＰＯ４（０．１＜ｘ＜０．９）等が挙げられる。
　これらのリチウム含有オリビン型リン酸塩の一部は他元素で置換してもよく、鉄、コバルト、ニッケル、マンガンの一部をＣｏ、Ｍｎ、Ｎｉ、Ｍｇ、Ａｌ、Ｂ、Ｔｉ、Ｖ、Ｎｂ、Ｃｕ、Ｚｎ、Ｍｏ、Ｃａ、Ｓｒ、Ｗ及びＺｒ等からなる群より選ばれる１種以上の元素で置換したり、又はこれらの他元素を含有する化合物や炭素材料で被覆することもできる。これらの中では、ＬｉＦｅＰＯ４及びＬｉＭｎＰＯ４が好ましい。
　また、リチウム含有オリビン型リン酸塩は、例えば前記の正極活物質と混合して用いることもできる。
　リチウム含有オリビン型リン酸塩は、安定したリン酸（ＰＯ４）構造を形成し、充電時の熱安定性に優れるため、高温かつ高電圧環境下での連続充電特性を向上することができる。 Furthermore, lithium-containing olivine-type phosphate can also be used as the positive electrode active material. In particular, a lithium-containing olivine-type phosphate containing at least one selected from iron, cobalt, nickel and manganese is preferable. Specific examples thereof include LiFePO 4 , LiCoPO 4 , LiNiPO 4 , LiMnPO 4 , and LiFe 1-x Mn x PO 4 (0.1 <x <0.9).
Some of these lithium-containing olivine-type phosphates may be substituted with other elements, and some of iron, cobalt, nickel, and manganese are replaced with Co, Mn, Ni, Mg, Al, B, Ti, V, and Nb. , Cu, Zn, Mo, Ca, Sr, W and Zr can be substituted with one or more elements selected from the group consisting of, or coated with a compound or carbon material containing these other elements. Among these, LiFePO 4 and LiMnPO 4 are preferable.
Moreover, lithium containing olivine type | mold phosphate can also be mixed with the said positive electrode active material, for example, and can be used.
Lithium-containing olivine-type phosphate forms a stable phosphoric acid (PO 4 ) structure and is excellent in thermal stability during charging. Therefore, continuous charging characteristics under high temperature and high voltage environment can be improved.
　また、リチウム一次電池用正極としては、ＣｕＯ、Ｃｕ２Ｏ、Ａｇ２Ｏ、Ａｇ２ＣｒＯ４、ＣｕＳ、ＣｕＳＯ４、ＴｉＯ２、ＴｉＳ２、ＳｉＯ２、ＳｎＯ、Ｖ２Ｏ５、Ｖ６Ｏ１２、ＶＯｘ、Ｎｂ２Ｏ５、Ｂｉ２Ｏ３、Ｂｉ２Ｐｂ２Ｏ５，Ｓｂ２Ｏ３、ＣｒＯ３、Ｃｒ２Ｏ３、ＭｏＯ３、ＷＯ３、ＳｅＯ２、ＭｎＯ２、Ｍｎ２Ｏ３、Ｆｅ２Ｏ３、ＦｅＯ、Ｆｅ３Ｏ４、Ｎｉ２Ｏ３、ＮｉＯ、ＣｏＯ３、ＣｏＯ等の、１種もしくは２種以上の金属元素の酸化物あるいはカルコゲン化合物、ＳＯ２、ＳＯＣｌ２等の硫黄化合物、一般式（ＣＦｘ）nで表されるフッ化炭素（フッ化黒鉛）等が挙げられる。これらの中でも、ＭｎＯ２、Ｖ２Ｏ５、及びフッ化黒鉛等が好ましい。 As the positive electrode for lithium primary battery, CuO, Cu 2 O, Ag 2 O, Ag 2 CrO 4, CuS, CuSO 4, TiO 2, TiS 2, SiO 2, SnO, V 2 O 5, V 6 O 12 , VO x , Nb 2 O 5 , Bi 2 O 3 , Bi 2 Pb 2 O 5 , Sb 2 O 3 , CrO 3 , Cr 2 O 3 , MoO 3 , WO 3 , SeO 2 , MnO 2 , Mn 2 O 3 , Fe 2 O 3 , FeO, Fe 3 O 4 , Ni 2 O 3 , NiO, CoO 3 , CoO and other oxides of one or more metal elements or chalcogen compounds, SO 2 , SOCl 2, etc. Examples thereof include sulfur compounds, and fluorocarbons (fluorinated graphite) represented by the general formula (CF x ) n . Among these, MnO 2 , V 2 O 5 , graphite fluoride and the like are preferable.
　正極の導電剤は、化学変化を起こさない電子伝導材料であれば特に制限はない。例えば、天然黒鉛（鱗片状黒鉛等）、人造黒鉛等のグラファイト、アセチレンブラック、ケッチェンブラック、チャンネルブラック、ファーネスブラック、ランプブラック、及びサーマルブラック等のカーボンブラック等が挙げられる。また、グラファイトとカーボンブラックを適宜混合して用いてもよい。導電剤の正極合剤への添加量は、１～１０質量％が好ましく、特に２～５質量％が好ましい。 The positive electrode conductive agent is not particularly limited as long as it is an electron conductive material that does not cause a chemical change. Examples thereof include graphite such as natural graphite (such as flake graphite) and artificial graphite, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. Further, graphite and carbon black may be appropriately mixed and used. The addition amount of the conductive agent to the positive electrode mixture is preferably 1 to 10% by mass, and particularly preferably 2 to 5% by mass.
　正極は、前記の正極活物質をアセチレンブラック、カーボンブラック等の導電剤、及びポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、スチレンとブタジエンの共重合体（ＳＢＲ）、アクリロニトリルとブタジエンの共重合体（ＮＢＲ）、カルボキシメチルセルロース（ＣＭＣ）、エチレンプロピレンジエンターポリマー等の結着剤と混合し、これに１－メチル－２－ピロリドン等の高沸点溶剤を加えて混練して正極合剤とした後、この正極合剤を集電体のアルミニウム箔やステンレス製のラス板等に塗布して、乾燥、加圧成型した後、５０℃～２５０℃程度の温度で２時間程度真空下で加熱処理することにより作製することができる。
　正極の集電体を除く部分の密度は、通常は１．５ｇ／ｃｍ３以上であり、電池の容量をさらに高めるため、好ましくは２ｇ／ｃｍ３以上であり、より好ましくは、３ｇ／ｃｍ３以上であり、更に好ましくは３．６ｇ／ｃｍ３以上である。なお、上限としては、４ｇ／ｃｍ３以下が好ましい。 The positive electrode is composed of a conductive agent such as acetylene black and carbon black, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of styrene and butadiene (SBR), acrylonitrile and butadiene. Mixture with binder such as copolymer (NBR), carboxymethyl cellulose (CMC), ethylene propylene diene terpolymer, etc., and knead by adding high boiling point solvent such as 1-methyl-2-pyrrolidone. After that, this positive electrode mixture was applied to a current collector aluminum foil, a stainless steel lath plate, etc., dried and pressure-molded, and then subjected to vacuum at a temperature of about 50 ° C. to 250 ° C. for about 2 hours. It can be manufactured by heat treatment.
The density of the part except the collector of the positive electrode is usually at 1.5 g / cm 3 or more, for further increasing the capacity of the battery, it is preferably 2 g / cm 3 or more, more preferably, 3 g / cm 3 It is above, More preferably, it is 3.6 g / cm 3 or more. The upper limit is preferably 4 g / cm 3 or less.
（負極活物質）
　リチウム二次電池用負極活物質としては、リチウム金属、リチウム合金、リチウムを吸蔵及び放出することが可能な炭素材料〔易黒鉛化炭素や、（００２）面の面間隔が０．３７ｎｍ以上の難黒鉛化炭素や、（００２）面の面間隔が０．３４ｎｍ以下の黒鉛等〕、スズ（単体）、スズ化合物、ケイ素（単体）、ケイ素化合物（ＳｉＯｘ：ｘ＜２）、ケイ素合金（Ｓｉ－Ｍ合金：Ｍは、Ａｌ、Ｎｉ、Ｃｕ、Ｆｅ、Ｔｉ及びＭｎからなる群より選ばれる少なくとも１種を含有する。）、及びＬｉ４Ｔｉ５Ｏ１２等のチタン酸リチウム化合物等からなる群より選ばれる１種又は２種以上が好ましい。
　これらの中では、リチウムイオンの吸蔵及び放出能力において、人造黒鉛や天然黒鉛等の高結晶性の炭素材料を使用することが更に好ましく、格子面（００２）の面間隔（ｄ００２）が０．３４０ｎｍ（ナノメータ）以下、特に０．３３５～０．３３７ｎｍである黒鉛型結晶構造を有する炭素材料を使用することが特に好ましい。 (Negative electrode active material)
Examples of the negative electrode active material for a lithium secondary battery include lithium metal, lithium alloy, and carbon material capable of occluding and releasing lithium [easily graphitized carbon and difficult to have a (002) plane spacing of 0.37 nm or more. Graphitized carbon, graphite with (002) plane spacing of 0.34 nm or less, etc.], tin (single), tin compound, silicon (single), silicon compound (SiOx: x <2), silicon alloy (Si— M alloy: M contains at least one selected from the group consisting of Al, Ni, Cu, Fe, Ti and Mn.), And a group consisting of lithium titanate compounds such as Li 4 Ti 5 O 12 1 type or 2 types or more selected are preferable.
Among these, it is more preferable to use a highly crystalline carbon material such as artificial graphite or natural graphite in terms of the ability to occlude and release lithium ions, and the plane spacing (d 002 ) of the lattice plane ( 002 ) is 0. It is particularly preferable to use a carbon material having a graphite type crystal structure of 340 nm (nanometer) or less, particularly 0.335 to 0.337 nm.
　複数の扁平状の黒鉛質微粒子が互いに非平行に集合或いは結合した塊状構造を有する人造黒鉛粒子や、例えば鱗片状天然黒鉛粒子に圧縮力、摩擦力、剪断力等の機械的作用を繰り返し与え、球形化処理を施した黒鉛粒子を用いることにより、負極の集電体を除く部分の密度を１．５ｇ／ｃｍ３以上の密度に加圧成形したときの負極シートのＸ線回折測定から得られる黒鉛結晶の（１１０）面のピーク強度Ｉ（１１０）と（００４）面のピーク強度Ｉ（００４）の比Ｉ（１１０）／Ｉ（００４）が０．０１以上となると一段と正極活物質からの金属溶出量の改善と、充電保存特性が向上するので好ましく、０．０５以上となることがより好ましく、０．１以上となることが更に好ましい。また、過度に処理し過ぎて結晶性が低下し電池の放電容量が低下する場合があるので、上限は０．５以下が好ましく、０．３以下がより好ましい。 A mechanical action such as compression force, friction force, shear force, etc. is repeatedly applied to artificial graphite particles having a massive structure in which a plurality of flat graphite fine particles are assembled or bonded non-parallel to each other, for example, scaly natural graphite particles, Using graphite particles that have been subjected to spheroidization treatment, the density of the portion excluding the current collector of the negative electrode can be obtained from X-ray diffraction measurement of the negative electrode sheet when pressed to a density of 1.5 g / cm 3 or more. When the ratio I (110) / I (004) of the peak intensity I (110) of the (110) plane of the graphite crystal to the peak intensity I (004) of the (004) plane is 0.01 or more, the graphite crystal It is preferable because the metal elution amount is improved and the charge storage characteristics are improved, more preferably 0.05 or more, and still more preferably 0.1 or more. Moreover, since it may process too much and crystallinity may fall and the discharge capacity of a battery may fall, an upper limit is preferable 0.5 or less, and 0.3 or less is more preferable.
　また、高結晶性の炭素材料（コア材）はコア材よりも低結晶性の炭素材料によって被膜されていると、高温かつ高電圧環境下での連続充電特性が一段と良好となるので好ましい。被覆の炭素材料の結晶性は、透過型電子顕微鏡（ＴＥＭ）により確認することができる。
　高結晶性の炭素材料を使用すると、一般的に、充電時において非水電解液と反応し、界面抵抗の増加によって高温かつ高電圧環境下での連続充電特性を低下させる傾向があるが、本発明に係るリチウム二次電池では高温かつ高電圧環境下での連続充電特性が良好となる。 In addition, it is preferable that the highly crystalline carbon material (core material) is coated with a carbon material that is less crystalline than the core material because continuous charge characteristics under a high temperature and high voltage environment are further improved. The crystallinity of the coating carbon material can be confirmed by a transmission electron microscope (TEM).
When a highly crystalline carbon material is used, it generally tends to react with a non-aqueous electrolyte during charging and reduce continuous charging characteristics under high temperature and high voltage environments due to an increase in interface resistance. The lithium secondary battery according to the invention has good continuous charge characteristics under high temperature and high voltage environment.
　また、負極活物質としてのリチウムイオンを吸蔵及び放出可能な金属化合物としては、Ｓｉ、Ｇｅ、Ｓｎ、Ｐｂ、Ｐ、Ｓｂ、Ｂｉ、Ａｌ、Ｇａ、Ｉｎ、Ｔｉ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ａｇ、Ｍｇ、Ｓｒ、又はＢａ等の金属元素を少なくとも１種含有する化合物が挙げられる。これらの金属化合物は単体、合金、酸化物、窒化物、硫化物、硼化物、リチウムとの合金等、何れの形態で用いてもよいが、単体、合金、酸化物、リチウムとの合金の何れかが高容量化できるので好ましい。これらの中でも、Ｓｉ、Ｇｅ及びＳｎから選ばれる少なくとも１種の元素を含有するものが好ましく、Ｓｉ及びＳｎから選ばれる少なくとも１種の元素を含むものが電池を高容量化できるので特に好ましい。 Examples of the metal compound capable of inserting and extracting lithium ions as the negative electrode active material include Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Examples thereof include compounds containing at least one metal element such as Cu, Zn, Ag, Mg, Sr, or Ba. These metal compounds may be used in any form such as a simple substance, an alloy, an oxide, a nitride, a sulfide, a boride, and an alloy with lithium, but any of a simple substance, an alloy, an oxide, and an alloy with lithium. Is preferable because the capacity can be increased. Among these, those containing at least one element selected from Si, Ge and Sn are preferable, and those containing at least one element selected from Si and Sn are particularly preferable because the capacity of the battery can be increased.
　負極は、上記の正極の作製と同様な導電剤、結着剤、高沸点溶剤を用いて混練して負極合剤とした後、この負極合剤を集電体の銅箔等に塗布して、乾燥、加圧成型した後、５０℃～２５０℃程度の温度で２時間程度真空下で加熱処理することにより作製することができる。
　負極の集電体を除く部分の密度は、通常は１．１ｇ／ｃｍ３以上であり、電池の容量をさらに高めるため、好ましくは１．５ｇ／ｃｍ３以上であり、特に好ましくは１．７ｇ／ｃｍ３以上である。なお、上限としては、２ｇ／ｃｍ３以下が好ましい。 The negative electrode is kneaded using the same conductive agent, binder, and high-boiling solvent as in the production of the positive electrode, and then the negative electrode mixture is applied to the copper foil of the current collector. After being dried and pressure-molded, it can be produced by heat treatment under vacuum at a temperature of about 50 ° C. to 250 ° C. for about 2 hours.
The density of the portion excluding the current collector of the negative electrode is usually 1.1 g / cm 3 or more, and is preferably 1.5 g / cm 3 or more, particularly preferably 1.7 g in order to further increase the capacity of the battery. / Cm 3 or more. The upper limit is preferably 2 g / cm 3 or less.
　また、リチウム一次電池用の負極活物質としては、リチウム金属又はリチウム合金が挙げられる。 Also, examples of the negative electrode active material for a lithium primary battery include lithium metal and lithium alloy.
　リチウム電池の構造には特に限定はなく、単層又は複層のセパレータを有するコイン型電池、円筒型電池、角型電池、ラミネート電池等を適用できる。
　電池用セパレータとしては、特に制限はされないが、ポリプロピレン、ポリエチレン等のポリオレフィンの単層又は積層の微多孔性フィルム、織布、不織布等を使用できる。 The structure of the lithium battery is not particularly limited, and a coin-type battery, a cylindrical battery, a square battery, a laminated battery, or the like having a single-layer or multi-layer separator can be applied.
Although it does not restrict | limit especially as a separator for batteries, The single layer or laminated | stacked microporous film, woven fabric, a nonwoven fabric, etc. of polyolefin, such as a polypropylene and polyethylene, can be used.
　本発明におけるリチウム二次電池は、充電終止電圧が４．２Ｖ以上、特に４．３Ｖ以上の場合にも高温かつ高電圧環境下での連続充電特性に優れ、更に、４．４Ｖ以上においても特性は良好である。放電終止電圧は、通常２．８Ｖ以上、更には２．５Ｖ以上とすることができるが、本願発明におけるリチウム二次電池は、２．０Ｖ以上とすることができる。電流値については特に限定されないが、通常０．１～３０Ｃの範囲で使用される。また、本発明におけるリチウム電池は、－４０～１００℃、好ましくは－１０～８０℃で充放電することができる。 The lithium secondary battery of the present invention is excellent in continuous charge characteristics under a high temperature and high voltage environment even when the end-of-charge voltage is 4.2 V or higher, particularly 4.3 V or higher, and is also characteristic at 4.4 V or higher. Is good. The end-of-discharge voltage is usually 2.8 V or higher, and more preferably 2.5 V or higher, but the lithium secondary battery in the present invention can be 2.0 V or higher. The current value is not particularly limited, but is usually used in the range of 0.1 to 30C. Further, the lithium battery in the present invention can be charged / discharged at −40 to 100 ° C., preferably −10 to 80 ° C.
　本発明においては、リチウム電池の内圧上昇の対策として、電池蓋に安全弁を設けたり、電池缶やガスケット等の部材に切り込みを入れる方法も採用することができる。また、過充電防止の安全対策として、電池の内圧を感知して電流を遮断する電流遮断機構を電池蓋に設けることができる。 In the present invention, as a countermeasure against an increase in internal pressure of the lithium battery, a method of providing a safety valve on the battery lid or cutting a member such as a battery can or a gasket can be employed. Further, as a safety measure for preventing overcharge, the battery lid can be provided with a current interruption mechanism that senses the internal pressure of the battery and interrupts the current.
〔第２の蓄電デバイス（電気二重層キャパシタ）〕
　本発明に係る第２の蓄電デバイスは、本発明の非水電解液を含み、電解液と電極界面の電気二重層容量を利用してエネルギーを貯蔵する蓄電デバイスである。本発明の一例は、電気二重層キャパシタである。この蓄電デバイスに用いられる最も典型的な電極活物質は、活性炭である。二重層容量は概ね表面積に比例して増加する。 [Second power storage device (electric double layer capacitor)]
The 2nd electrical storage device which concerns on this invention is an electrical storage device which stores the energy using the electric double layer capacity | capacitance of electrolyte solution and an electrode interface including the non-aqueous electrolyte of this invention. An example of the present invention is an electric double layer capacitor. The most typical electrode active material used for this electricity storage device is activated carbon. Double layer capacity increases roughly in proportion to surface area.
〔第３の蓄電デバイス〕
　本発明に係る第３の蓄電デバイスは、本発明の非水電解液を含み、電極のドープ／脱ドープ反応を利用してエネルギーを貯蔵する蓄電デバイスである。この蓄電デバイスに用いられる電極活物質として、酸化ルテニウム、酸化イリジウム、酸化タングステン、酸化モリブデン、酸化銅等の金属酸化物や、ポリアセン、ポリチオフェン誘導体等のπ共役高分子が挙げられる。これらの電極活物質を用いたキャパシタは、電極のドープ／脱ドープ反応にともなうエネルギー貯蔵が可能である。 [Third power storage device]
The 3rd electrical storage device which concerns on this invention is an electrical storage device which stores the energy using the dope / dedope reaction of an electrode including the non-aqueous electrolyte of this invention. Examples of the electrode active material used in this power storage device include metal oxides such as ruthenium oxide, iridium oxide, tungsten oxide, molybdenum oxide, and copper oxide, and π-conjugated polymers such as polyacene and polythiophene derivatives. Capacitors using these electrode active materials can store energy associated with electrode doping / dedoping reactions.
〔第４の蓄電デバイス（リチウムイオンキャパシタ）〕
　本発明に係る第４の蓄電デバイスは、本発明の非水電解液を含み、負極であるグラファイト等の炭素材料へのリチウムイオンのインターカレーションを利用してエネルギーを貯蔵する蓄電デバイスである。リチウムイオンキャパシタ（ＬＩＣ）と呼ばれる。正極は、例えば活性炭電極と電解液との間の電気二重層を利用したものや、π共役高分子電極のドープ／脱ドープ反応を利用したもの等が挙げられる。電解液には少なくともＬｉＰＦ6等のリチウム塩が含まれる。 [Fourth storage device (lithium ion capacitor)]
The 4th electrical storage device which concerns on this invention is an electrical storage device which stores the energy using the intercalation of the lithium ion to carbon materials, such as graphite which is a negative electrode, containing the non-aqueous electrolyte of this invention. It is called a lithium ion capacitor (LIC). Examples of the positive electrode include those using an electric double layer between an activated carbon electrode and an electrolytic solution, and those using a π-conjugated polymer electrode doping / dedoping reaction. The electrolyte contains at least a lithium salt such as LiPF 6 .
　以下、本発明の化合物を用いた電解液の実施例を示すが、本発明は、これらの実施例に限定されるものではない。 Examples of the electrolytic solution using the compound of the present invention are shown below, but the present invention is not limited to these examples.
実施例１～４５、比較例１～４
〔リチウムイオン二次電池の作製〕
　ＬｉＮｉ０．８Ｃｏ０．１Ｍｎ０．１Ｏ２ ９２質量％、アセチレンブラック（導電剤）５質量％を混合し、予めポリフッ化ビニリデン（結着剤）３質量％を１－メチル－２－ピロリドンに溶解させておいた溶液に加えて混合し、正極合剤ペーストを調製した。この正極合剤ペーストをアルミニウム箔（集電体）上の片面に塗布し、乾燥、加圧処理して所定の大きさに裁断し、正極シートを作製した。正極の集電体を除く部分の密度は３．６ｇ／ｃｍ３であった。
　また、ケイ素（単体）５質量％、人造黒鉛（ｄ００２＝０．３３５ｎｍ、負極活物質）９０質量％を、予めポリフッ化ビニリデン（結着剤）５質量％を１－メチル－２－ピロリドンに溶解させておいた溶液に加えて混合し、負極合剤ペーストを調製した。この負極合剤ペーストを銅箔（集電体）上の片面に塗布し、乾燥、加圧処理して所定の大きさに裁断し負極シートを作製した。負極の集電体を除く部分の密度は１．５ｇ／ｃｍ３であった。また、この電極シートを用いてＸ線回折測定した結果、黒鉛結晶の（１１０）面のピーク強度Ｉ（１１０）と（００４）面のピーク強度Ｉ（００４）の比〔Ｉ（１１０）／Ｉ（００４）〕は０．１であった。
　そして、正極シート、微多孔性ポリエチレンフィルム製セパレータ、負極シートの順に積層し、表１～５に記載の組成の非水電解液を加えて、ラミネート型電池を作製した。
　なお、比較例４で使用したイオン液体は、特開２００８－１２３８９８号の合成例２により製造したものであり、その構造は以下のとおりである。 Examples 1 to 45, Comparative Examples 1 to 4
[Production of lithium ion secondary battery]
92% by mass of LiNi 0.8 Co 0.1 Mn 0.1 O 2 and 5% by mass of acetylene black (conductive agent) are mixed, and 3% by mass of polyvinylidene fluoride (binder) is previously added to 1-methyl-2- A positive electrode mixture paste was prepared by adding to and mixing with the solution dissolved in pyrrolidone. This positive electrode mixture paste was applied to one side of an aluminum foil (current collector), dried and pressurized, and cut into a predetermined size to produce a positive electrode sheet. The density of the portion excluding the current collector of the positive electrode was 3.6 g / cm 3 .
Further, 5% by mass of silicon (single substance), 90% by mass of artificial graphite (d 002 = 0.335 nm, negative electrode active material) and 5% by mass of polyvinylidene fluoride (binder) in advance are added to 1-methyl-2-pyrrolidone. A negative electrode mixture paste was prepared by adding to the dissolved solution and mixing. This negative electrode mixture paste was applied to one side of a copper foil (current collector), dried and pressurized, and cut into a predetermined size to produce a negative electrode sheet. The density of the portion excluding the current collector of the negative electrode was 1.5 g / cm 3 . As a result of X-ray diffraction measurement using this electrode sheet, the ratio of the peak intensity I (110) of the (110) plane of the graphite crystal to the peak intensity I (004) of the (004) plane [I (110) / I (004)] was 0.1.
Then, a positive electrode sheet, a microporous polyethylene film separator, and a negative electrode sheet were laminated in this order, and a non-aqueous electrolyte solution having the composition shown in Tables 1 to 5 was added thereto to produce a laminate type battery.
The ionic liquid used in Comparative Example 4 was produced according to Synthesis Example 2 of Japanese Patent Application Laid-Open No. 2008-123898, and its structure is as follows.
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
〔高温連続充電特性の評価〕
＜初期放電容量＞
　上記の方法で作製したラミネート電池を用いて、２５℃の恒温槽中、０．２Ｃの定電流及び定電圧で、終止電圧４．３Ｖまで７時間充電し、０．２Ｃの定電流下、終止電圧２．５Ｖまで放電することで初期放電容量を求めた。その後、１Ｃの定電流及び定電圧で、終止電圧４．３Ｖまで３時間充電し、１Ｃの定電流下、終止電圧２．５Ｖまで放電した。この１Ｃの定電流で放電した時の平均の放電電圧を初期の平均放電電圧とした。 [Evaluation of high-temperature continuous charge characteristics]
<Initial discharge capacity>
Using the laminated battery produced by the above method, the battery was charged in a constant temperature bath at 25 ° C. with a constant current and a constant voltage of 0.2 C for 7 hours to a final voltage of 4.3 V, and terminated under a constant current of 0.2 C. The initial discharge capacity was determined by discharging to a voltage of 2.5V. Thereafter, the battery was charged with a constant current and a constant voltage of 1 C for 3 hours to a final voltage of 4.3 V, and discharged to a final voltage of 2.5 V under a constant current of 1 C. The average discharge voltage when discharged at a constant current of 1 C was taken as the initial average discharge voltage.
＜連続充電試験＞
　次に、このラミネート型電池を６０℃の恒温槽中、０．２Ｃの定電流で４．３Ｖまで充電した後、定電圧に切り替えて連続充電を７日間行った。その後、２５℃の恒温槽に入れ、１Ｃの定電流下、終止電圧２．５Ｖまで放電した。
　引き続き、２５℃の恒温槽中、０．２Ｃの定電流及び定電圧で、終止電圧４．３Ｖまで７時間充電し、０．２Ｃの定電流下、終止電圧２．５Ｖまで放電することで連続充電後の回復放電容量を求めた。連続充電後の放電容量回復率を以下の式により求めた。
　放電容量回復率（％）＝（回復放電容量／初期放電容量）×１００ <Continuous charging test>
Next, this laminate type battery was charged to 4.3 V at a constant current of 0.2 C in a constant temperature bath at 60 ° C., and then switched to a constant voltage for 7 days. Then, it put into a 25 degreeC thermostat, and discharged to final voltage 2.5V under the constant current of 1C.
Subsequently, in a constant temperature bath at 25 ° C., the battery is continuously charged by charging at a constant current of 0.2 C and a constant voltage for 7 hours to a final voltage of 4.3 V, and discharging to a final voltage of 2.5 V under a constant current of 0.2 C. The recovery discharge capacity after charging was determined. The discharge capacity recovery rate after continuous charging was determined by the following formula.
Discharge capacity recovery rate (%) = (Recovery discharge capacity / initial discharge capacity) × 100
＜連続充電後の平均放電電圧低下率＞
　引き続き、１Ｃの定電流及び定電圧で、終止電圧４．３Ｖまで３時間充電し、１Ｃの定電流下、終止電圧２．５Ｖまで放電した。この１Ｃの定電流で放電した時の平均の放電電圧を連続充電後の平均放電電圧として、以下の式により平均放電電圧変化率を算出した。
　平均放電電圧変化率（相対値）（％）＝（初期の平均放電電圧－連続充電後の平均放電電圧）／（比較例１の初期の平均放電電圧－比較例１の連続充電後の平均放電電圧）×１００ <Average discharge voltage drop rate after continuous charging>
Subsequently, the battery was charged with a constant current and a constant voltage of 1 C to a final voltage of 4.3 V for 3 hours, and discharged under a constant current of 1 C to a final voltage of 2.5 V. The average discharge voltage change rate was calculated by the following equation, using the average discharge voltage when discharged at a constant current of 1 C as the average discharge voltage after continuous charging.
Average discharge voltage change rate (relative value) (%) = (initial average discharge voltage−average discharge voltage after continuous charge) / (initial average discharge voltage in comparative example 1−average discharge after continuous charge in comparative example 1) Voltage) x 100
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　上記実施例１～４５のリチウム二次電池は何れも、本願発明の添加剤を含まない比較例１や一般式（Ｉ）で表される化合物のみを含む比較例２と比べて、高温保存後の容量回復率及び平均放電電圧低下率が顕著に向上している。
　また比較例３に示すように、特開２００８－１２３８９８号（特許文献１）に記載のメチルシクロヘキシルカーボネート及びアリルメチルカーボネートを添加した非水電解液では高温保存後の容量回復率及び平均放電電圧低下率の向上は不十分であった。
　加えて特許文献１に記載のシクロヘキシルメチルカーボネートとイオン液体を含む電解液においても同じく高温保存後の容量回復率及び平均放電電圧低下率の向上は不十分であった。以上より、本発明の効果は、非水溶媒に電解質塩が溶解されている非水電解液において、本願発明の特定量の一般式（Ｉ）で表される化合物とフッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を組み合わせて含有させた場合に特有の効果であることが判明した。 All of the lithium secondary batteries of Examples 1 to 45 were compared with Comparative Example 1 not containing the additive of the present invention and Comparative Example 2 containing only the compound represented by the general formula (I) after high-temperature storage. The capacity recovery rate and the average discharge voltage drop rate are significantly improved.
In addition, as shown in Comparative Example 3, in the non-aqueous electrolyte to which methylcyclohexyl carbonate and allylmethyl carbonate described in JP-A-2008-123898 (Patent Document 1) are added, the capacity recovery rate after storage at high temperature and the average discharge voltage drop are reduced. The rate improvement was insufficient.
In addition, in the electrolytic solution containing cyclohexylmethyl carbonate and ionic liquid described in Patent Document 1, the capacity recovery rate and the average discharge voltage reduction rate after high-temperature storage were also insufficient. As described above, the effects of the present invention are as follows. In a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a non-aqueous solvent, a specific amount of the compound represented by the general formula (I) of the present invention, a fluorine atom-containing cyclic carbonate, It has been found that the effect is unique when at least one selected from the group consisting of saturated bond-containing cyclic carbonates is contained in combination.
　更に、本発明の非水電解液は、リチウムイオンキャパシタ、リチウム空気電池等の高温保存後の容量回復率及び平均放電電圧低下率を改善する効果も有する。 Furthermore, the non-aqueous electrolyte of the present invention also has an effect of improving the capacity recovery rate and average discharge voltage reduction rate after high-temperature storage such as lithium ion capacitors and lithium air batteries.
　本発明の非水電解液を使用すれば、高温かつ高電圧環境下での連続充電特性に優れた蓄電デバイスを得ることができる。特にハイブリッド電気自動車、プラグインハイブリッド電気自動車、バッテリー電気自動車等に搭載される蓄電デバイス用の非水電解液として使用される場合、高温かつ高電圧環境下での連続充電特性を向上できる蓄電デバイスを得ることができる。
  If the non-aqueous electrolyte of the present invention is used, an electricity storage device having excellent continuous charging characteristics under a high temperature and high voltage environment can be obtained. In particular, when used as a non-aqueous electrolyte for power storage devices mounted on hybrid electric vehicles, plug-in hybrid electric vehicles, battery electric vehicles, etc., a power storage device capable of improving the continuous charging characteristics under high temperature and high voltage environment. Obtainable.

Claims (13)

  1. 　非水溶媒に電解質塩が溶解されている非水電解液であって、非水電解液中に下記一般式（Ｉ）で表される化合物を０．１～４質量％含有し、添加剤としてフッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種を０．１～３０質量％含有することを特徴とする蓄電デバイス用非水電解液。
    Figure JPOXMLDOC01-appb-C000001
    （式中、Ｒ１は炭素数１～７のアルキル基又は炭素数３～６のシクロアルキル基を示し、Ｒ2～Ｒ6はそれぞれ独立に、水素原子、炭素数１～４のアルキル基、又は－ＣＨ２ＯＣ（＝Ｏ）ＯＲ７基を示し、Ｒ７は炭素数１～４のアルキル基を示し、ｎ＝０又は１を示す。     A non-aqueous electrolyte in which an electrolyte salt is dissolved in a non-aqueous solvent, containing 0.1 to 4% by mass of a compound represented by the following general formula (I) in the non-aqueous electrolyte, A nonaqueous electrolytic solution for an electricity storage device, comprising 0.1 to 30% by mass of at least one selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate.
    Figure JPOXMLDOC01-appb-C000001
    (Wherein R 1 represents an alkyl group having 1 to 7 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and R 2 to R 6 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, Or —CH 2 OC (═O) OR 7 group, R 7 represents an alkyl group having 1 to 4 carbon atoms, and n = 0 or 1.
  2. 　前記一般式（Ｉ）で表される化合物が、メチルシクロヘキシルカーボネート、メチル（２－メチルシクロヘキシル）カーボネート、メチル（３－メチルシクロヘキシル）カーボネート、メチル（４－メチルシクロヘキシル）カーボネート、エチルシクロヘキシルカーボネート、エチル（２－メチルシクロヘキシル）カーボネート、エチル（３－メチルシクロヘキシル）カーボネート、エチル（４－メチルシクロヘキシル）カーボネート、ジシクロヘキシルカーボネート、シクロヘキシルメチルメチルカーボネート、シクロヘキシルメチルエチルカーボネート、ビス（シクロヘキシルメチル）カーボネート、シクロヘキサン－１，４－ジイルビス（メチレン）ジメチルビス（カーボネート）、及びシクロヘキサン－１，４－ジイルビス（メチレン）ジエチルビス（カーボネート）からなる群より選ばれる１種以上である、請求項１に記載の非水電解液。 The compound represented by the general formula (I) is methyl cyclohexyl carbonate, methyl (2-methyl cyclohexyl) carbonate, methyl (3-methyl cyclohexyl) carbonate, methyl (4-methyl cyclohexyl) carbonate, ethyl cyclohexyl carbonate, ethyl ( 2-methylcyclohexyl) carbonate, ethyl (3-methylcyclohexyl) carbonate, ethyl (4-methylcyclohexyl) carbonate, dicyclohexyl carbonate, cyclohexylmethyl methyl carbonate, cyclohexylmethyl ethyl carbonate, bis (cyclohexylmethyl) carbonate, cyclohexane-1,4 -Diylbis (methylene) dimethylbis (carbonate) and cyclohexane-1,4-diylbis (methyl) Emissions) Jiechirubisu (at least one selected from the group consisting of carbonate), non-aqueous electrolyte according to claim 1.
  3. 　前記フッ素原子含有環状カーボネートが、４－フルオロ－１，３－ジオキソラン－２－オン及びトランスもしくはシス－４，５－ジフルオロ－１，３－ジオキソラン－２－オンからなる群より選ばれる１種以上である、請求項１又は２に記載の非水電解液。 The fluorine atom-containing cyclic carbonate is one or more selected from the group consisting of 4-fluoro-1,3-dioxolan-2-one and trans or cis-4,5-difluoro-1,3-dioxolan-2-one The nonaqueous electrolytic solution according to claim 1 or 2, wherein
  4. 　前記不飽和結合含有環状カーボネートが、ビニレンカーボネート、ビニルエチレンカーボネート、及び４－エチニル－１，３－ジオキソラン－２－オンからなる群より選ばれる１種以上である、請求項１又は２に記載の非水電解液。 The unsaturated bond-containing cyclic carbonate is at least one selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, and 4-ethynyl-1,3-dioxolan-2-one. Non-aqueous electrolyte.
  5. 一般式（Ｉ）で表される化合物の含有量をＡ質量％、フッ素原子含有環状カーボネート及び不飽和結合含有環状カーボネートからなる群より選ばれる少なくとも１種の含有量をＢ質量％としたときにＡ／Ｂが０．０１～３の範囲である、請求項１～４のいずれか１項に記載の非水電解液。 When the content of the compound represented by the general formula (I) is A mass%, and at least one content selected from the group consisting of a fluorine atom-containing cyclic carbonate and an unsaturated bond-containing cyclic carbonate is B mass%. The nonaqueous electrolytic solution according to any one of claims 1 to 4, wherein A / B is in the range of 0.01 to 3.
  6. 　該非水電解液が、更にシュウ酸構造を有するリチウム塩、リン酸構造を有するリチウム塩、Ｓ＝Ｏ基を有するリチウム塩、及びフッ素原子を有するリチウムイミド塩からなる群より選ばれる１種以上のリチウム塩を含む、請求項１～５のいずれか１項に記載の非水電解液。 The non-aqueous electrolyte further includes at least one selected from the group consisting of a lithium salt having an oxalic acid structure, a lithium salt having a phosphoric acid structure, a lithium salt having an S═O group, and a lithium imide salt having a fluorine atom. The nonaqueous electrolytic solution according to any one of claims 1 to 5, comprising a lithium salt.
  7. 　前記シュウ酸構造を有するリチウム塩が、リチウム　ビス（オキサラト）ボレート、リチウム　ジフルオロ（オキサラト）ボレート、リチウム　テトラフルオロ（オキサラト）ホスフェート、及びリチウム　ジフルオロビス（オキサラト）ホスフェートからなる群より選ばれる１種又は２種以上である、請求項６に記載の非水電解液。 The lithium salt having the oxalic acid structure is one or two selected from the group consisting of lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium tetrafluoro (oxalato) phosphate, and lithium difluorobis (oxalato) phosphate. The nonaqueous electrolytic solution according to claim 6, which is a seed or more.
  8. 　前記リン酸構造を有するリチウム塩が、ＬｉＰＯ２Ｆ２、Ｌｉ２ＰＯ３Ｆ、リチウム　ビス（ジフルオロホスホリル）アミド、リチウム（ジフルオロホスホリル）（フルオロオキシドホスホリル）アミドからなる群より選ばれる１種又は２種以上である、請求項６に記載の非水電解液。 The lithium salt having the phosphoric acid structure is one or two selected from the group consisting of LiPO 2 F 2 , Li 2 PO 3 F, lithium bis (difluorophosphoryl) amide, lithium (difluorophosphoryl) (fluorooxidephosphoryl) amide The nonaqueous electrolytic solution according to claim 6, which is a seed or more.
  9. 　前記Ｓ＝Ｏ基を有するリチウム塩が、リチウム　トリフルオロ（（メタンスルホニル）オキシ）ボレート、リチウム　ペンタフルオロ（（メタンスルホニル）オキシ）ホスフェート、リチウム　メチルサルフェート、リチウムエチルサルフェート、リチウム　２，２，２－トリフルオロエチルサルフェート、及びＦＳＯ３Ｌｉからなる群より選ばれる１種又は２種以上である、請求項６に記載の非水電解液。 The lithium salt having the S═O group is lithium trifluoro ((methanesulfonyl) oxy) borate, lithium pentafluoro ((methanesulfonyl) oxy) phosphate, lithium methyl sulfate, lithium ethyl sulfate, lithium 2,2,2- The nonaqueous electrolytic solution according to claim 6, which is one or more selected from the group consisting of trifluoroethyl sulfate and FSO 3 Li.
  10. 前記フッ素原子を有するリチウムイミド塩が、ＬｉＮ（ＳＯ２Ｆ）２及びＬｉＮ（ＳＯ２ＣＦ３）２から選ばれる１種又は２種である、請求項６に記載の非水電解液。 The nonaqueous electrolytic solution according to claim 6, wherein the lithium imide salt having a fluorine atom is one or two selected from LiN (SO 2 F) 2 and LiN (SO 2 CF 3 ) 2 .
  11. 　前記非水電解液において、非水溶媒に鎖状エステルを１種以上含む、請求項１～１０のいずれか１項に記載の非水電解液。 The nonaqueous electrolytic solution according to any one of claims 1 to 10, wherein the nonaqueous electrolytic solution contains one or more chain esters in a nonaqueous solvent.
  12. 　前記鎖状エステルが、ジメチルカーボネート、メチルエチルカーボネート、ジエチルカーボネート、酢酸プロピル、酢酸ブチル、プロピオン酸メチル、プロピオン酸エチル、プロピオン酸プロピル、及びピバリン酸メチルから選ばれる１種又は２種である、請求項１１に記載の非水電解液。 The chain ester is one or two selected from dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, and methyl pivalate, Item 12. A nonaqueous electrolytic solution according to Item 11.
  13. 　正極、負極、及び非水溶媒に電解質塩が溶解されている非水電解液を備えた蓄電デバイスであって、該非水電解液が請求項１～１２のいずれか１項に記載の非水電解液であることを特徴とする蓄電デバイス。
          An electricity storage device comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte in which an electrolyte salt is dissolved in a non-aqueous solvent, wherein the non-aqueous electrolyte is the non-aqueous electrolysis according to any one of claims 1 to 12. An electricity storage device characterized by being a liquid.
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WO2017069278A1 (en) * 2015-10-23 2017-04-27 宇部興産株式会社 Non-aqueous electrolyte solution and power storage device using same

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CN114008830A (en) * 2019-03-29 2022-02-01 株式会社大阪曹达 Nonaqueous electrolyte solution for electricity storage device and electricity storage device using same
WO2022203048A1 (en) * 2021-03-26 2022-09-29 Ｍｕアイオニックソリューションズ株式会社 Non-aqueous electrolyte and non-aqueous electrolyte battery using same

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