WO2013069791A1 - Non-aqueous electrolyte secondary cell - Google Patents

Non-aqueous electrolyte secondary cell Download PDF

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Publication number
WO2013069791A1
WO2013069791A1 PCT/JP2012/079180 JP2012079180W WO2013069791A1 WO 2013069791 A1 WO2013069791 A1 WO 2013069791A1 JP 2012079180 W JP2012079180 W JP 2012079180W WO 2013069791 A1 WO2013069791 A1 WO 2013069791A1
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compound
formula
aqueous electrolyte
secondary battery
electrolyte secondary
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PCT/JP2012/079180
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French (fr)
Japanese (ja)
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真男 岩谷
康人 神座
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旭硝子株式会社
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Publication of WO2013069791A1 publication Critical patent/WO2013069791A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—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
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a non-aqueous electrolyte secondary battery, particularly a lithium ion secondary battery.
  • Lithium ion secondary batteries are widely used in portable electronic devices such as mobile phones and notebook computers. In recent years, it is also expected to be used as an in-vehicle power source for driving a motor, which is the key to the spread of electric vehicles, in order to solve environmental and energy problems. However, in order to obtain a practical on-vehicle power source for driving a motor, a discharge capacity capable of obtaining a sufficient travel distance is required, and a battery having a higher energy density is desired.
  • lithium cobalt oxide LiCoO 2
  • LiNiO 2 lithium nickel compound
  • LiCo cobalt nickel manganese composite oxide for example, LiCo 1/3 Ni 1/3 Mn 1
  • Layered rock salt type compounds such as / 3 O 2
  • spinel type manganese compounds LiMn 2 O 4
  • olivine iron lithium compounds LiFePO 4
  • any of these positive electrode materials has a capacity density of less than 200 mAh / g, and a sufficient discharge capacity cannot be obtained as an in-vehicle power source for driving a motor.
  • Patent Document 1 proposes a positive electrode material for a lithium ion battery, characterized in that an oxidation treatment is performed on a positive electrode material for a lithium ion battery using the same solid solution.
  • Patent Document 3 a nonaqueous electrolyte mainly composed of ⁇ -butyrolactone has been proposed as a nonaqueous electrolyte that can withstand a high charging voltage.
  • Patent Document 4 a non-aqueous electrolyte containing a specific bissulfonylimide salt has been proposed.
  • the solid solution positive electrode using Li 2 MnO 3 which is a high capacity positive electrode candidate material described in Patent Document 1 has a large discharge capacity, but if the charge / discharge potential is high, the cycle characteristics are poor. There was a problem that it deteriorated easily by repeated discharge. Therefore, even a lithium ion battery using such a solid solution positive electrode as a high-capacity positive electrode has a problem that cycle durability under a high-capacity use condition is poor, and deterioration occurs immediately when charging / discharging at a high voltage. It was.
  • Patent Document 2 an attempt is made to improve the above-described degradation problem by oxidation treatment, but the high-voltage charge / discharge cycle characteristics still do not have practically sufficient performance.
  • the non-aqueous electrolyte of Patent Document 3 has only been confirmed to have cycle characteristics of about 10 cycles while being able to withstand a high charge voltage, and can withstand the use of repeated charge / discharge required in practice. I can not say.
  • the non-aqueous electrolyte of patent document 4 it is not examined whether practically sufficient cycle characteristics can be obtained by charging and discharging at a high voltage.
  • the present invention has been made in view of the above problems, can be charged at a high voltage, can have a high capacity, and can withstand the use of repetitive charging / discharging that is practically required as an in-vehicle power source for driving a motor. It is an object to provide a nonaqueous electrolyte secondary battery to be obtained.
  • the non-aqueous electrolyte is One or more compounds ( ⁇ ) selected from the group consisting of a cyclic carbonate compound, a chain carbonate compound, a cyclic ester compound, and a chain ester compound, and LiPF 6 , LiClO 4 , LiBF 4 , and the general formula (A)
  • a non-aqueous electrolyte secondary battery Li (Li x Mn y
  • Rf 1 and Rf 2 are each independently a C 1 to C 4 perfluoroalkyl group that may contain an etheric oxygen atom, and Y 1 and Y 2 are each independently a halogen atom. An atom or a hydrogen atom.
  • Rf 1 and Rf 2 of the compound represented by the formula (II) are both trifluoromethyl groups, and Y 1 and Y 2 are each independently a hydrogen atom or a fluorine atom.
  • the nonaqueous electrolyte secondary battery as described. [3] The above [1] or [2], wherein the content of the compound represented by the formula (II) in the nonaqueous electrolytic solution is 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the base electrolytic solution.
  • non-aqueous electrolyte secondary battery that can be charged at a high voltage to obtain a high capacity and that can withstand the use of repeated charge and discharge that is practically required.
  • the non-aqueous electrolyte secondary battery of the present invention has a positive electrode and a negative electrode facing each other with a separator interposed therebetween, and a non-aqueous electrolyte.
  • a compound represented by the following formula (I) or formula (I ′) is used as the positive electrode active material.
  • the notation of the compound represented by the formula (I) or the formula (I ′) is a composition formula before performing treatment such as charge / discharge and activation.
  • the activation means removing lithium oxide (Li 2 O) or lithium and lithium oxide from the positive electrode active material.
  • an ordinary activation method there is an electrochemical activation method in which charging is performed at a voltage higher than 4.4 V or 4.6 V (a value expressed as a potential difference from the oxidation-reduction potential of Li + / Li).
  • the activation method performed chemically is mentioned by performing the chemical reaction using acids, such as a sulfuric acid, hydrochloric acid, or nitric acid.
  • Me ′ is at least one selected from Co, Ni, Cr, Fe, Al, Ti, Zr and Mg. Further, x, y, z, p, and q in the formula (I) satisfy the relationships of the following formulas (I-1) to (I-8). 0.09 ⁇ x ⁇ 0.3 ............
  • the proportion of Li exceeds 1.2 times mol with respect to the total of transition metal elements Mn and Me ′.
  • the composition ratio of Li element to the total molar amount of the transition metal element is preferably 1.25 ⁇ (1 + x) / (y + z) ⁇ 1.75, and 1.35 ⁇ (1 + x) / (y + z) ⁇ 1.65. More preferably, 1.40 ⁇ (1 + x) / (y + z) ⁇ 1.55 is particularly preferable.
  • the composition ratio is in the above range, a positive electrode material having a high discharge capacity per unit mass can be obtained when a high charging voltage of 4.6 V or higher is applied.
  • the compound (I) contains Mn. Further, the ratio of Mn to the total amount of Mn and Me ′ is 0.4 to 0.8 as shown in the formula (I-6), and preferably 0.55 to 0.75. When the proportion of Mn is in the range of formula (I-6), the discharge capacity becomes high.
  • q represents the proportion of F, but includes 0 as shown in Formula (I-5). That is, the compound (I) includes a compound in which F is not present.
  • p is a value determined according to x, y, z, and q, and is in a range exceeding 1.9 and less than 2.1 as shown in Formula (I-4).
  • the compound (I ′) represented by the following formula (I ′) is more preferable.
  • the proportion of Li exceeds 1.2 times mol with respect to the total of transition metal elements Mn, Ni, and Co. Less than 8.
  • the composition ratio of the Li element to the total molar amount of the transition metal element is preferably 1.35 ⁇ (1 + x) / (y + v + w) ⁇ 1.65, and 1.45 ⁇ (1 + x) / (y + v + w) ⁇ 1.55. More preferred.
  • the composition ratio is in the above range, a positive electrode material having a high discharge capacity per unit mass can be obtained when a high charging voltage of 4.6 V or higher is applied.
  • Compound (I) or Compound (I ′) preferably has a layered rock salt type crystal structure (space group R-3m).
  • XRD X-ray diffraction
  • the surface of the compound (I) or the compound (I ′) is at least one metal element selected from the group consisting of Al, Y, Ga, In, La, Pr, Nd, Gd, Dy, Er, and Yb.
  • a compound containing Li and a nonmetallic element P, S, B).
  • the positive electrode is formed by forming a positive electrode layer containing a positive electrode active material, a conductivity-imparting agent, and a binder on a current collector.
  • a conductivity-imparting agent in addition to a carbon material, a conductive oxide powder or the like can be used.
  • the binder a resin binder such as polyvinylidene fluoride and / or a rubber binder such as hydrocarbon rubber or fluorine rubber can be used.
  • As the current collector a metal thin film mainly composed of Al or the like can be used.
  • the content of the conductivity-imparting agent in the positive electrode is preferably 1 to 10% by mass of the entire positive electrode layer, and the content of the binder is also preferably about 1 to 10% by mass of the entire positive electrode layer.
  • the ratio between the conductivity-imparting agent and the binder is equal to or less than the preferable upper limit value, the ratio of the active material in the positive electrode layer can be sufficiently secured, and a sufficient capacity per unit mass can be obtained. If the ratio between the conductivity-imparting agent and the binder is too small, the conductivity may not be maintained, or a problem of electrode peeling may occur.
  • the proportion of the active material in the positive electrode layer is preferably 80 to 98% by mass.
  • the negative electrode is formed by forming a negative electrode layer containing a powdered negative electrode active material, a conductivity-imparting agent, and a binder on a current collector.
  • the negative electrode active material used for the negative electrode is not particularly limited as long as lithium ions can be occluded during charging and released during discharging, and known materials can be used. Specific examples include carbon materials such as graphite, coke, and hard carbon, lithium alloys such as lithium-aluminum alloy, lithium-lead alloy, and lithium-tin alloy, lithium metal, Si, SnO 2 , SnO, TiO 2 , and Nb 2.
  • a metal oxide having a base potential lower than that of the positive electrode active material such as O 2 SiO, can be used.
  • the negative electrode binder and the conductivity-imparting agent those equivalent to the positive electrode can be used.
  • the current collector a metal thin film mainly composed of Cu or the like can be used.
  • the negative electrode active material can keep its shape by itself (for example, a lithium metal thin film), the negative electrode can be formed only with the negative electrode active material.
  • a non-aqueous electrolyte is an electrolyte that does not substantially contain water, and even if it contains water, the amount of water is in a range where performance degradation of a secondary battery using the non-aqueous electrolyte is not observed.
  • the amount of water that can be contained in the non-aqueous electrolyte is preferably 500 ppm by mass or less, more preferably 100 ppm by mass or less, and 50 ppm by mass or less with respect to the total mass of the non-aqueous electrolyte. It is particularly preferred.
  • the lower limit of the moisture content is 0 mass ppm.
  • the nonaqueous electrolytic solution in the present invention comprises a base electrolytic solution and one or more compounds represented by the general formula (II) described later.
  • the base electrolyte contains one or more compounds ( ⁇ ) and one or more lithium salts ( ⁇ ) described below.
  • the compound ( ⁇ ) is a compound selected from the group consisting of a cyclic carbonate compound, a chain carbonate compound, a cyclic ester compound, and a chain ester compound.
  • the proportion of the compound ( ⁇ ) in the base electrolyte is preferably 50 to 99.8% by mass, more preferably 60 to 99.5% by mass, and 70 to 99% by mass. Particularly preferred.
  • the lithium salt ( ⁇ ) can be dissolved well. Moreover, if it is below a preferable upper limit, sufficient quantity of lithium salt ((beta)) can be contained.
  • the cyclic carbonate compound is a compound in which the ring skeleton has a ring structure composed of carbon atoms and oxygen atoms, and the ring structure has a carbonate bond represented by —O—C ( ⁇ O) —O—. .
  • the ring structure in the cyclic carbonate compound is preferably a 4- to 10-membered ring, more preferably a 4- to 7-membered ring, more preferably a 5- to 6-membered ring, and particularly preferably a 5-membered ring from the viewpoint of availability.
  • the ring structure of the cyclic carbonate compound is preferably a ring structure having one carbonate bond.
  • a ring structure in which a carbonate bond is formed by linking with a linear alkylene group or vinylene group is more preferable.
  • the linear alkylene group preferably has 1 to 7 carbon atoms, more preferably 1 to 4, more preferably 2 or 3 2 is particularly preferable.
  • Specific examples include propylene carbonate (PC) and ethylene carbonate (EC).
  • Examples of the carbonate compound having a ring structure in which a carbonate bond is linked to a vinylene group include vinylene carbonate and dimethyl vinylene carbonate, and vinylene carbonate is particularly preferable.
  • the cyclic carbonate compound is also preferably a compound in which one or more hydrogen atoms of the linear alkylene group are substituted with a substituent.
  • a substituent for example, a halogen atom, an alkyl group, a halogenated alkyl group, a vinyl group, or an allyl group is preferable. Specific examples include fluoroethylene carbonate.
  • the base electrolyte contains a cyclic carbonate compound
  • the cyclic carbonate compound may be only one type or two or more types. The inclusion of a cyclic carbonate compound is preferable because the dielectric constant of the non-aqueous electrolyte can be increased.
  • the chain carbonate compound is a chain compound having no carbonate structure and having a carbonate bond represented by —O—C ( ⁇ O) —O—.
  • the chain carbonate compound is preferably a chain monocarbonate having one carbonate bond. Examples of the chain monocarbonate include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC).
  • DMC dimethyl carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the chain carbonate compound may be only one type or two or more types. It is preferable to contain a chain carbonate compound because the viscosity of the nonaqueous electrolytic solution can be reduced.
  • the cyclic ester compound is a compound in which the ring skeleton has a ring structure composed of a carbon atom and an oxygen atom, and the ring structure has an ester bond represented by —O—C ( ⁇ O) —C—. .
  • the cyclic ester compound is preferably a compound that does not contain a carbon-carbon unsaturated bond in the molecule.
  • the cyclic structure in the cyclic ester compound is preferably a 4- to 10-membered ring, more preferably a 4- to 7-membered ring, more preferably a 5- to 6-membered ring, and particularly preferably a 5-membered ring from the viewpoint of availability.
  • the ring structure of the cyclic ester compound is preferably a ring structure having one ester bond, and more preferably a ring structure formed by linking an ester bond with a linear alkylene group.
  • the linear alkylene group preferably has 1 to 7 carbon atoms, more preferably 1 to 4, more preferably 2 or 3, and particularly preferably 2.
  • the cyclic ester compound may be a compound in which one or more hydrogen atoms of the linear alkylene group are substituted with a substituent. Examples of the substituent include a halogen atom, an alkyl group, and a halogenated alkyl group.
  • cyclic ester compounds such as ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -hexanolactone, and ⁇ -valerolactone, and one hydrogen atom bonded to the carbon atom forming the ring structure of the cyclic ester compound.
  • examples thereof include compounds in which at least one group is substituted with a halogen atom, an alkyl group, or a halogenated alkyl group.
  • ⁇ -butyrolactone or ⁇ -valerolactone is preferable, and ⁇ -butyrolactone is particularly preferable from the viewpoint of easy availability and properties of the electrolytic solution.
  • the cyclic ester compound may be only one type or two or more types. The inclusion of a cyclic ester compound is preferable because the stability of the electrolytic solution is improved.
  • the chain ester compound is a chain compound that has no ring structure and has an ester bond represented by —O—C ( ⁇ O) —C—.
  • the chain ester compound is preferably a chain monoester having one ester bond. Examples of the chain monoester include ethyl acetate, ethyl butyrate, butyl acetate and the like.
  • the chain ester compound may be only one type or two or more types. It is preferable to include a chain ester compound because the viscosity of the electrolytic solution can be easily reduced.
  • the base electrolyte may contain any two or more of a cyclic carbonate compound, a chain carbonate compound, a cyclic ester compound, and a chain ester compound. You may contain all four types.
  • the base electrolyte solution preferably contains one or more compounds ( ⁇ ′) selected from the group consisting of the following compound (1), compound (2), and compound (3).
  • R 1 to R 12 are each independently a hydrogen atom, a halogen atom, an alkyl group, or a halogenated alkyl group, and X is an oxygen atom or CH 2 .
  • R 1 to R 12 are halogen atoms, each is preferably independently a fluorine atom or a chlorine atom.
  • R 1 to R 12 are alkyl groups, the alkyl group preferably has 1 to 6 carbon atoms.
  • R 1 to R 12 are halogenated alkyl groups, the alkyl group preferably has 1 to 6 carbon atoms, and the halogen atom is preferably a fluorine atom or a chlorine atom.
  • the proportion of the compound ( ⁇ ′) in the base electrolyte solution that is, the proportion of the total amount of the compound (1), the compound (2) and the compound (3) in the base electrolyte solution is 50 to 99.8% by mass. It is preferably 60 to 99.5% by mass, more preferably 70 to 99% by mass.
  • the ratio of each of the compound (1), the compound (2), and the compound (3) to the entire compound ( ⁇ ′) is 5 to 100 mass% for the compound (1) and 0 to 95 mass for the compound (2).
  • the compound (3) is preferably 0 to 10% by mass, the compound (1) is 10 to 100% by mass, the compound (2) is 0 to 90% by mass, and the compound (3) is 0 to 5% by mass. More preferably, the compound (1) is 20 to 100% by mass, the compound (2) is 0 to 80% by mass, and the compound (3) is particularly preferably 0 to 3% by mass.
  • the lithium salt ( ⁇ ) is LiPF 6 , LiClO 4 , LiBF 4 , the following compound (A) (where k is an integer of 1 to 5), the following compound (B), the following compound (C), LiCF 3.
  • Examples of the compound (A) include the following compound (A-1) to compound (A-4).
  • the compound (A) preferably includes a compound (A-2) in which k is 2, and is composed of a compound (A-2) in which k is 2, from the viewpoint of easily obtaining a non-aqueous electrolyte with high conductivity. It is more preferable.
  • the concentration of the lithium salt ( ⁇ ) in the base electrolyte is preferably 0.5 mol / l to 1.5 mol / l. In terms of mass, it is preferably 5 to 50% by mass, more preferably 8 to 30% by mass, and further preferably 10 to 20% by mass. If this concentration is too high, the viscosity increases, and if the concentration is too low, the electrical conductivity decreases.
  • the lithium salt ( ⁇ ) is preferably dissolved in the base electrolyte.
  • the base electrolyte may contain a conventional nonaqueous electrolyte solvent other than those described above.
  • chain ethers such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE) and ethoxymethoxyethane (EME), cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran, dimethyl sulfoxide , Formamide, acetamide, dimethylformamide, dioxolane, acetonitrile, propyl nitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, Examples include 3-methyl-2-oxazolidinone, ethylene carbonate derivatives, propylene carbonate derivatives, tetrahydrofuran derivatives,
  • the nonaqueous electrolytic solution of the present invention contains one or more compounds represented by the formula (II).
  • Rf 1 and Rf 2 are each independently a C 1 to C 4 perfluoroalkyl group which may contain an etheric oxygen atom
  • Y 1 and Y 2 are each independently a halogen atom.
  • Rf 1 and Rf 2 are preferably the same as each other, and Y 1 and Y 2 are also preferably the same as each other.
  • Rf 1 and Rf 2 are both trifluoromethyl groups, and Y 1 and Y 2 are preferably each independently a hydrogen atom or a fluorine atom. Only one type of compound (II) may be used, or two or more types may be used.
  • the energy density can be maintained by suppressing the decrease in the average discharge voltage even when charging and discharging are performed at a high voltage.
  • the content of compound (II) in the non-aqueous electrolyte is preferably 0.2 to 10.0 parts by mass, and 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the base electrolyte. It is more preferable. When the content of compound (II) is at least the preferred lower limit, it becomes easy to obtain good high potential charge / discharge cycle characteristics. When the content of the compound (II) is not more than the preferable upper limit value, various characteristics of the electrolytic solution such as conductivity and low temperature characteristics can be achieved at a high level.
  • the material and shape of the porous membrane as the separator are not particularly limited as long as it is stable with respect to the non-aqueous electrolyte and has excellent liquid retention properties.
  • Polyvinylidene fluoride, polytetrafluoroethylene, ethylene and tetrafluoroethylene A porous sheet or non-woven fabric made of a fluororesin such as a copolymer, polyimide, or a polyolefin such as polyethylene or polypropylene is preferred, and the material is preferably a polyolefin such as polyethylene or polypropylene.
  • the lithium secondary battery according to the present invention is, for example, laminated in a dry air or an inert gas atmosphere by laminating a negative electrode and a positive electrode via a separator, or winding the laminated one, and then in an outer container such as a can case.
  • a battery can be manufactured by housing, injecting an electrolytic solution, and sealing with a flexible film made of a laminate of a synthetic resin and a metal foil.
  • the configuration and shape of the battery is not particularly limited, and can take the form of a positive electrode facing the separator, a wound type wound with the negative electrode, a laminated type, etc., and a coin type, laminate pack, square type, etc. It can take the form of a cell, a cylindrical cell or the like.
  • the charging voltage of the lithium secondary battery according to the present invention is preferably 4.2 V or higher, more preferably 4.4 V or higher, and particularly preferably 4.5 V or higher. Moreover, 5.0V or less is preferable, 4.9V or less is more preferable, and 4.8V or less is especially preferable.
  • LiPF 6 was dissolved in a carbonate-based solvent in which ethylene carbonate and diethyl carbonate were mixed in an equal volume so as to have a concentration of 1M (1 mol LiPF 6 / l (liter) electrolytic solution) to obtain a test electrolytic solution of a reference example.
  • a specific additive was added at a specific ratio to obtain test electrolyte solutions of Examples and Comparative Examples.
  • Table 1 shows the types and amounts of additives in the test electrolytes of the examples and comparative examples (the test electrolyte of the reference example is 100 parts by mass).
  • the compound (II-1) in Table 1 is a compound represented by the chemical formula (II-1).
  • a negative electrode was prepared by punching a lithium metal foil having a thickness of 300 ⁇ m into a circle having a diameter of 19 mm.
  • a separator a polyolefin microporous film having a thickness of 20 ⁇ m was present between the positive electrode and the negative electrode, and 0.5 mL of each test electrolyte was added thereto to prepare an evaluation cell.
  • Table 1 shows the number of cycles when the charge / discharge cycle test was stopped. Further, Table 1 shows the ratio of the discharge capacity at the time when the charge / discharge cycle test is stopped to the discharge capacity at the fifth cycle as the discharge capacity maintenance ratio when the 80 cycles are completed or when it is stopped halfway.
  • Table 2 shows the ratio of the average discharge voltage at the completion of 80 cycles to the average discharge voltage at the fifth cycle as the average discharge voltage maintenance ratio.
  • Table 3 shows the ratio with respect to the discharge energy of the 5th cycle of the discharge energy at the time of 80th cycle completion as a discharge energy maintenance factor.
  • the discharge energy is a numerical value represented by the product of the discharge capacity and the average discharge voltage. The larger the numerical value, the larger the work that can be performed by the nonaqueous electrolyte secondary battery.
  • Example 1 As shown in Tables 1 and 2, in Example 1, high values were obtained for both the discharge capacity retention ratio and the average discharge voltage at the 80th cycle. As a result, as shown in Table 3, a high discharge energy maintenance rate was obtained.
  • the non-aqueous electrolyte secondary battery of the present invention can be charged at a high voltage to obtain a high capacity, and can be used as a vehicle-mounted power source for driving a motor. It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2011-247640 filed on November 11, 2011 are incorporated herein as the disclosure of the specification of the present invention. Is.

Abstract

Provided is a non-aqueous electrolyte secondary cell which charges at high voltages, which can obtain high capacities and which can withstand the repeated use demanded in real applications as a vehicle-mounted power source for driving a motor. This non-aqueous electrolyte secondary cell is characterized by comprising a positive electrode having a compound represented by general formula (I) as the positive electrode active substance, a negative electrode, and a non-aqueous electrolyte containing a lithium salt, wherein the non-aqueous electrolyte contains one or more compounds represented by general formula (II) as an essential component. Li(LixMnyMe'z)OpFq ... (I)

Description

非水電解液二次電池Non-aqueous electrolyte secondary battery
　本発明は、非水電解液二次電池、特にリチウムイオン二次電池に関する。 The present invention relates to a non-aqueous electrolyte secondary battery, particularly a lithium ion secondary battery.
　リチウムイオン二次電池は、携帯電話やノート型パソコン等の携帯型電子機器に広く用いられている。また、近年、環境、エネルギー問題の解決へ向けて、電気自動車普及の鍵を握るモータ駆動用の車載電源としても期待されている。
　しかしながら、実用的なモータ駆動用の車載電源とするためには、充分な走行距離が得られる放電容量が必要であり、より高エネルギー密度の電池が望まれている。 Lithium ion secondary batteries are widely used in portable electronic devices such as mobile phones and notebook computers. In recent years, it is also expected to be used as an in-vehicle power source for driving a motor, which is the key to the spread of electric vehicles, in order to solve environmental and energy problems.
However, in order to obtain a practical on-vehicle power source for driving a motor, a discharge capacity capable of obtaining a sufficient travel distance is required, and a battery having a higher energy density is desired.
　現在、リチウム二次電池用の正極活物質としては、リチウムコバルト酸化物（ＬｉＣｏＯ２）、リチウムニッケル化合物（ＬｉＮｉＯ２）、リチウムコバルトニッケルマンガン複合酸化物（例えばＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２）等の層状岩塩型化合物や、スピネル型マンガン化合物（ＬｉＭｎ２Ｏ４）、オリビン鉄リチウム化合物（ＬｉＦｅＰＯ４）等が知られている。しかしながら、これらの正極材料はいずれも容量密度が２００ｍＡｈ／ｇに満たず、モータ駆動用の車載電源としては、充分な放電容量が得られない。 Currently, as a positive electrode active material for a lithium secondary battery, lithium cobalt oxide (LiCoO 2 ), a lithium nickel compound (LiNiO 2 ), a lithium cobalt nickel manganese composite oxide (for example, LiCo 1/3 Ni 1/3 Mn 1) Layered rock salt type compounds such as / 3 O 2 ), spinel type manganese compounds (LiMn 2 O 4 ), olivine iron lithium compounds (LiFePO 4 ) and the like are known. However, any of these positive electrode materials has a capacity density of less than 200 mAh / g, and a sufficient discharge capacity cannot be obtained as an in-vehicle power source for driving a motor.
　この要請にこたえられる可能性のある正極材料としていわゆる固溶体系正極が検討されている。なかでも、電気化学的に不活性の層状のＬｉ２ＭｎＯ３と、電気化学的に活性な層状のＬｉＭＯ２（ここでＭは、Ｃｏ、Ｎｉ等の遷移金属）との固溶体であって、Ｎｉ、Ｃｏ、Ｍｎ等の遷移金属元素に対するＬｉ元素の比率を高くした複合酸化物は、２００ｍＡｈ／ｇを超える大きなエネルギー密度を示しうる高容量正極候補材料として期待されている（たとえば特許文献１）。
　また、特許文献２では同様の固溶体を用いたリチウムイオン電池用正極材料において、酸化処理が施されていることを特徴とするリチウムイオン電池用正極材料が提案されている。 A so-called solid solution positive electrode has been studied as a positive electrode material that may meet this demand. Among them, a solid solution of an electrochemically inactive layered Li 2 MnO 3 and an electrochemically active layered LiMO 2 (where M is a transition metal such as Co or Ni), A composite oxide having a higher ratio of Li element to transition metal element such as Co, Mn, etc. is expected as a high-capacity positive electrode candidate material capable of exhibiting a large energy density exceeding 200 mAh / g (for example, Patent Document 1).
Patent Document 2 proposes a positive electrode material for a lithium ion battery, characterized in that an oxidation treatment is performed on a positive electrode material for a lithium ion battery using the same solid solution.
　また、高い放電容量を得るためには高い充電電圧が必要であるが、充電電圧が高いと非水電解液の分解が生じサイクル特性が悪化しやすい。そこで、高い充電電圧に耐えうる非水電解液として、γ－ブチロラクトンを主成分とする非水電解液が提案されている（特許文献３）。
　一方、非水電解液二次電池の安全性の性能を向上させるため、特定のビススルホニルイミド塩を含有する非水電解液が提案されている（特許文献４） Moreover, in order to obtain a high discharge capacity, a high charging voltage is required. However, if the charging voltage is high, the non-aqueous electrolyte is decomposed and the cycle characteristics are likely to deteriorate. In view of this, a nonaqueous electrolyte mainly composed of γ-butyrolactone has been proposed as a nonaqueous electrolyte that can withstand a high charging voltage (Patent Document 3).
On the other hand, in order to improve the safety performance of a non-aqueous electrolyte secondary battery, a non-aqueous electrolyte containing a specific bissulfonylimide salt has been proposed (Patent Document 4).
日本特許第３５３９５１８号公報Japanese Patent No. 3539518 日本特開２００８－２７０２０１号公報Japanese Unexamined Patent Publication No. 2008-270201 日本特開２００３－２７２７０４号公報Japanese Unexamined Patent Publication No. 2003-272704 国際公開第２０１１／０３４１４９号International Publication No. 2011/034149
　しかしながら、上記特許文献１に記載の高容量正極候補材料であるＬｉ２ＭｎＯ３を用いた固溶体系の正極では、放電容量は大きいものの、充放電電位を高くして使用すると、サイクル特性が悪く充放電の繰り返しで容易に劣化してしまうという問題があった。そのため、こうした固溶体系の正極を高容量正極として用いたリチウムイオン電池でも、高容量使用条件でのサイクル耐久性が悪く、高電圧にして充放電を行うとすぐに劣化してしまうという問題があった。
　特許文献２では、酸化処理により上記劣化の問題を改善する試みがなされているが、依然高電圧の充放電サイクル特性は、実用上充分な性能となっていない。 However, the solid solution positive electrode using Li 2 MnO 3 which is a high capacity positive electrode candidate material described in Patent Document 1 has a large discharge capacity, but if the charge / discharge potential is high, the cycle characteristics are poor. There was a problem that it deteriorated easily by repeated discharge. Therefore, even a lithium ion battery using such a solid solution positive electrode as a high-capacity positive electrode has a problem that cycle durability under a high-capacity use condition is poor, and deterioration occurs immediately when charging / discharging at a high voltage. It was.
In Patent Document 2, an attempt is made to improve the above-described degradation problem by oxidation treatment, but the high-voltage charge / discharge cycle characteristics still do not have practically sufficient performance.
　また、特許文献３の非水電解液は、高い充電電圧に耐えうるとされながら、１０サイクル程度のサイクル特性が確認されただけであり、実用上求められる繰り返し充放電の使用に耐え得るとは言えない。
　また、特許文献４の非水電解液では、高電圧の充放電で、実用上充分なサイクル特性が得られるか否かの検討がされていない。
　本発明は、上記問題に鑑みなされたものであり、高電圧で充電し、高容量を得ることが可能であり、かつ、モータ駆動用の車載電源として実用上求められる繰り返し充放電の使用に耐え得る非水電解液二次電池を提供することを課題とする。 Further, the non-aqueous electrolyte of Patent Document 3 has only been confirmed to have cycle characteristics of about 10 cycles while being able to withstand a high charge voltage, and can withstand the use of repeated charge / discharge required in practice. I can not say.
Moreover, in the non-aqueous electrolyte of patent document 4, it is not examined whether practically sufficient cycle characteristics can be obtained by charging and discharging at a high voltage.
The present invention has been made in view of the above problems, can be charged at a high voltage, can have a high capacity, and can withstand the use of repetitive charging / discharging that is practically required as an in-vehicle power source for driving a motor. It is an object to provide a nonaqueous electrolyte secondary battery to be obtained.
　本発明は、以下の構成を要旨とするものである。
［１］一般式（Ｉ）で表わされる化合物を正極活物質とする正極と、負極と、非水電解液と、を有し、
　前記非水電解液は、
環状カーボネート化合物、鎖状カーボネート化合物、環状エステル化合物、および鎖状エステル化合物からなる群から選択される１種以上の化合物（α）と、ＬｉＰＦ６、ＬｉＣｌＯ４、ＬｉＢＦ４、一般式（Ａ）で表される化合物、一般式（Ｂ）で表される化合物、一般式（Ｃ）で表される化合物、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＣＯ２、ＬｉＣ（ＣＦ３ＳＯ２）３、およびＬｉＮ（ＣＦ３ＳＯ２）２からなる群から選択される１種以上のリチウム塩（β）と、を含むベース電解液と、一般式（ＩＩ）で表わされる１種以上の化合物と、を含有することを特徴とする非水電解液二次電池。
　Ｌｉ（ＬｉｘＭｎｙＭｅ´ｚ）ＯｐＦｑ　…………（Ｉ） The gist of the present invention is as follows.
[1] A positive electrode having a compound represented by the general formula (I) as a positive electrode active material, a negative electrode, and a nonaqueous electrolytic solution,
The non-aqueous electrolyte is
One or more compounds (α) selected from the group consisting of a cyclic carbonate compound, a chain carbonate compound, a cyclic ester compound, and a chain ester compound, and LiPF 6 , LiClO 4 , LiBF 4 , and the general formula (A) Compounds represented by general formula (B), compounds represented by general formula (C), LiCF 3 SO 3 , LiC 4 F 9 CO 2 , LiC (CF 3 SO 2 ) 3 , and LiN A base electrolyte containing one or more lithium salts (β) selected from the group consisting of (CF 3 SO 2 ) 2 and one or more compounds represented by the general formula (II) A non-aqueous electrolyte secondary battery.
Li (Li x Mn y Me' z ) O p F q ............ (I)
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　ただし、式（Ｉ）において、Ｍｅ´は、Ｃｏ、Ｎｉ、Ｃｒ、Ｆｅ、Ａｌ、Ｔｉ、ＺｒおよびＭｇからなる群から選ばれる少なくとも１種である。
　また、０．０９＜ｘ＜０．３、ｙ＞０、ｚ＞０、１．９＜ｐ＜２．１、０≦ｑ≦０．１であり、かつ０．４≦ｙ／（ｙ＋ｚ）≦０．８、ｘ＋ｙ＋ｚ＝１、１．２＜（１＋ｘ）／（ｙ＋ｚ）である。
　また、式（Ａ）において、ｋは１～５の整数である。
　また、式（ＩＩ）において、Ｒｆ１、Ｒｆ２は、それぞれ独立にエーテル性酸素原子を含んでもよい炭素数１から４のパーフルオロアルキル基であり、Ｙ１、Ｙ２は、それぞれ独立にハロゲン原子もしくは水素原子である。 However, in the formula (I), Me ′ is at least one selected from the group consisting of Co, Ni, Cr, Fe, Al, Ti, Zr and Mg.
Further, 0.09 <x <0.3, y> 0, z> 0, 1.9 <p <2.1, 0 ≦ q ≦ 0.1, and 0.4 ≦ y / (y + z) ≦ 0.8, x + y + z = 1, 1.2 <(1 + x) / (y + z).
In the formula (A), k is an integer of 1 to 5.
In Formula (II), Rf 1 and Rf 2 are each independently a C 1 to C 4 perfluoroalkyl group that may contain an etheric oxygen atom, and Y 1 and Y 2 are each independently a halogen atom. An atom or a hydrogen atom.
［２］式（ＩＩ）で表わされる化合物のＲｆ１、Ｒｆ２が、いずれもトリフルオロメチル基であり、Ｙ１、Ｙ２は、それぞれ独立に水素原子またはフッ素原子である上記［１］に記載の非水電解液二次電池。
［３］非水電解液における式（ＩＩ）で表わされる化合物の含有量が、ベース電解液１００質量部に対して、０．２～１０．０質量部である上記［１］または［２］に記載の非水電解液二次電池。
［４］前記ベース電解液に占める前記化合物（α）の割合が、５０～９９．８質量％である上記［１］～［３］のいずれか一項に記載の非水電解液二次電池。
［５］前記ベース電解液における前記リチウム塩（β）の濃度が、０．５ｍｏｌ／ｌ～１．５ｍｏｌ／ｌである上記［１］～［４］のいずれか一項に記載の非水電解液二次電池。
［６］式（Ｉ）で表される化合物が下式（Ｉ’）で表される化合物である上記［１］～［５］のいずれか一項に記載の非水電解液二次電池。
　Ｌｉ（ＬｉｘＭｎｙＮｉｖＣｏｗ）Ｏｐ　…………（Ｉ’）
　ただし、式（Ｉ’）において、０．０９＜ｘ＜０．３、０．３６＜ｙ＜０．７３、０＜ｖ＜０．３２、０＜ｗ＜０．３２、１．９＜ｐ＜２．１、ｘ＋ｙ＋ｖ＋ｗ＝１、１．２＜（１＋ｘ）／（ｙ＋ｖ＋ｗ）＜１．８である。
［７］充電電圧を４．４Ｖ以上として用いる上記［１］～［６］のいずれか一項に記載の非水電解液二次電池。 [2] In the above [1], Rf 1 and Rf 2 of the compound represented by the formula (II) are both trifluoromethyl groups, and Y 1 and Y 2 are each independently a hydrogen atom or a fluorine atom. The nonaqueous electrolyte secondary battery as described.
[3] The above [1] or [2], wherein the content of the compound represented by the formula (II) in the nonaqueous electrolytic solution is 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the base electrolytic solution. A nonaqueous electrolyte secondary battery according to 1.
[4] The nonaqueous electrolyte secondary battery according to any one of [1] to [3], wherein the ratio of the compound (α) in the base electrolyte is 50 to 99.8% by mass. .
[5] The nonaqueous electrolysis according to any one of [1] to [4], wherein the concentration of the lithium salt (β) in the base electrolyte is 0.5 mol / l to 1.5 mol / l. Liquid secondary battery.
[6] The nonaqueous electrolyte secondary battery according to any one of [1] to [5], wherein the compound represented by the formula (I) is a compound represented by the following formula (I ′).
Li (Li x Mn y Ni v Co w) O p ............ (I ')
However, in the formula (I ′), 0.09 <x <0.3, 0.36 <y <0.73, 0 <v <0.32, 0 <w <0.32, 1.9 <p <2.1, x + y + v + w = 1, 1.2 <(1 + x) / (y + v + w) <1.8.
[7] The nonaqueous electrolyte secondary battery according to any one of the above [1] to [6], wherein the charging voltage is 4.4 V or higher.
　本発明によれば、高電圧で充電し、高容量を得ることが可能であり、かつ、実用上求められる繰り返し充放電の使用に耐え得る非水電解液二次電池を提供することができる。 According to the present invention, it is possible to provide a non-aqueous electrolyte secondary battery that can be charged at a high voltage to obtain a high capacity and that can withstand the use of repeated charge and discharge that is practically required.
　本明細書中では、特に説明しない限り、式（Ｉ）で表される化合物を化合物（Ｉ）と示し、他の式についても同様に示す。本発明の非水電解液二次電池は、セパレータを挟んで対向する正極および負極と、非水電解液と、を有している。 In the present specification, unless otherwise specified, the compound represented by the formula (I) is referred to as the compound (I), and other formulas are also shown in the same manner. The non-aqueous electrolyte secondary battery of the present invention has a positive electrode and a negative electrode facing each other with a separator interposed therebetween, and a non-aqueous electrolyte.
［正極］
　本発明の正極では、正極活物質としては、下記式（Ｉ）または式（Ｉ’）で表される化合物を用いる。式（Ｉ）または式（Ｉ’）で表される化合物の表記は、充放電や活性化等の処理を行う前の組成式である。ここで、活性化とは、酸化リチウム（Ｌｉ２Ｏ）、またはリチウムおよび酸化リチウムを、正極活物質から取り除くことをいう。通常の活性化方法としては、４．４Ｖまたは４．６Ｖ（Ｌｉ＋／Ｌｉの酸化還元電位との電位差として表わされる値である。）より大きな電圧で充電する電気化学的活性化法が挙げられる。また、硫酸、塩酸または硝酸等の酸を用いた化学反応を行うことにより、化学的に行う活性化方法が挙げられる。 [Positive electrode]
In the positive electrode of the present invention, a compound represented by the following formula (I) or formula (I ′) is used as the positive electrode active material. The notation of the compound represented by the formula (I) or the formula (I ′) is a composition formula before performing treatment such as charge / discharge and activation. Here, the activation means removing lithium oxide (Li 2 O) or lithium and lithium oxide from the positive electrode active material. As an ordinary activation method, there is an electrochemical activation method in which charging is performed at a voltage higher than 4.4 V or 4.6 V (a value expressed as a potential difference from the oxidation-reduction potential of Li + / Li). . Moreover, the activation method performed chemically is mentioned by performing the chemical reaction using acids, such as a sulfuric acid, hydrochloric acid, or nitric acid.
　Ｌｉ（ＬｉｘＭｎｙＭｅ´ｚ）ＯｐＦｑ　…………（Ｉ）
　ただし、式（Ｉ）において、Ｍｅ´は、Ｃｏ、Ｎｉ、Ｃｒ、Ｆｅ、Ａｌ、Ｔｉ、ＺｒおよびＭｇから選ばれる少なくとも１種である。
　また、式（Ｉ）のｘ、ｙ、ｚ、ｐ、ｑは、以下の式（Ｉ－１）～（Ｉ－８）の関係を満たしている。
　０．０９＜ｘ＜０．３…………（Ｉ－１）
　ｙ＞０…………（Ｉ－２）
　ｚ＞０…………（Ｉ－３）
　１．９＜ｐ＜２．１…………（Ｉ－４）
　０≦ｑ≦０．１…………（Ｉ－５）
　０．４≦ｙ／（ｙ＋ｚ）≦０．８…………（Ｉ－６）
　ｘ＋ｙ＋ｚ＝１…………（Ｉ－７）
　１．２＜（１＋ｘ）／（ｙ＋ｚ）…………（Ｉ－８） Li (Li x Mn y Me' z ) O p F q ............ (I)
However, in the formula (I), Me ′ is at least one selected from Co, Ni, Cr, Fe, Al, Ti, Zr and Mg.
Further, x, y, z, p, and q in the formula (I) satisfy the relationships of the following formulas (I-1) to (I-8).
0.09 <x <0.3 ............ (I-1)
y> 0 ………… (I-2)
z> 0 ………… (I-3)
1.9 <p <2.1 ………… (I-4)
0 ≦ q ≦ 0.1 ………… (I-5)
0.4 ≦ y / (y + z) ≦ 0.8 …… (I-6)
x + y + z = 1 ………… (I-7)
1.2 <(1 + x) / (y + z) ............ (I-8)
　式（Ｉ－８）に示すように、化合物（Ｉ）は、Ｌｉの割合が、遷移金属元素であるＭｎとＭｅ´の合計に対して１．２倍モルを超える。
　前記遷移金属元素の総モル量に対するＬｉ元素の組成比は、１．２５≦（１＋ｘ）／（ｙ＋ｚ）≦１．７５が好ましく、１．３５≦（１＋ｘ）／（ｙ＋ｚ）≦１．６５がより好ましく、１．４０≦（１＋ｘ）／（ｙ＋ｚ）≦１．５５が特に好ましい。この組成比が前記の範囲であれば、４．６Ｖ以上の高い充電電圧を印加した場合に、単位質量あたりの放電容量が高い正極材料が得られる。 As shown in the formula (I-8), in the compound (I), the proportion of Li exceeds 1.2 times mol with respect to the total of transition metal elements Mn and Me ′.
The composition ratio of Li element to the total molar amount of the transition metal element is preferably 1.25 ≦ (1 + x) / (y + z) ≦ 1.75, and 1.35 ≦ (1 + x) / (y + z) ≦ 1.65. More preferably, 1.40 ≦ (1 + x) / (y + z) ≦ 1.55 is particularly preferable. When the composition ratio is in the above range, a positive electrode material having a high discharge capacity per unit mass can be obtained when a high charging voltage of 4.6 V or higher is applied.
　また、式（Ｉ－２）に示すように、化合物（Ｉ）はＭｎを含む。また、ＭｎとＭｅ´の総量に対するＭｎの割合は、式（Ｉ－６）に示すように０．４～０．８であり、０．５５～０．７５が好ましい。Ｍｎの割合が式（Ｉ－６）の範囲であれば、放電容量が高容量となる。
　ｑはＦの割合を示すが、式（Ｉ－５）に示すように０を含む。すなわち、化合物（Ｉ）には、Ｆが存在しない化合物が含まれる。
　ｐは、ｘ、ｙ、ｚおよびｑに応じて決まる値であり、式（Ｉ－４）に示すように、１．９を超え２．１に満たない範囲である。 Further, as shown in the formula (I-2), the compound (I) contains Mn. Further, the ratio of Mn to the total amount of Mn and Me ′ is 0.4 to 0.8 as shown in the formula (I-6), and preferably 0.55 to 0.75. When the proportion of Mn is in the range of formula (I-6), the discharge capacity becomes high.
q represents the proportion of F, but includes 0 as shown in Formula (I-5). That is, the compound (I) includes a compound in which F is not present.
p is a value determined according to x, y, z, and q, and is in a range exceeding 1.9 and less than 2.1 as shown in Formula (I-4).
　化合物（Ｉ）の中でも、下式（Ｉ’）で表される化合物（Ｉ’）がより好ましい。
　Ｌｉ（ＬｉｘＭｎｙＮｉｖＣｏｗ）Ｏｐ　…………（Ｉ’）
　ただし、式（Ｉ’）のｘ、ｙ、ｖ、ｗ、ｐは、以下の式（Ｉ’－１）～（Ｉ’－７）の関係を満たしている。
　０．０９＜ｘ＜０．３…………（Ｉ’－１）
　０．３６＜ｙ＜０．７３…………（Ｉ’－２）
　０＜ｖ＜０．３２…………（Ｉ’－３）
　０＜ｗ＜０．３２…………（Ｉ’－４）
　１．９＜ｐ＜２．１…………（Ｉ’－５）
　ｘ＋ｙ＋ｖ＋ｗ＝１…………（Ｉ’－６）
　１．２＜（１＋ｘ）／（ｙ＋ｖ＋ｗ）＜１．８…………（Ｉ’－７） Among the compounds (I), the compound (I ′) represented by the following formula (I ′) is more preferable.
Li (Li x Mn y Ni v Co w) O p ............ (I ')
However, x, y, v, w, and p in the formula (I ′) satisfy the relationships of the following formulas (I′-1) to (I′-7).
0.09 <x <0.3 ............ (I'-1)
0.36 <y <0.73 ………… (I'-2)
0 <v <0.32 ………… (I'-3)
0 <w <0.32 ………… (I'-4)
1.9 <p <2.1 ............ (I'-5)
x + y + v + w = 1 ………… (I'-6)
1.2 <(1 + x) / (y + v + w) <1.8 ………… (I′−7)
　式（Ｉ’－７）に示すように、化合物（Ｉ’）は、Ｌｉの割合が、遷移金属元素であるＭｎ、Ｎｉ、およびＣｏの合計に対して１．２倍モルを超え、１．８に満たない。
　前記遷移金属元素の総モル量に対するＬｉ元素の組成比は、１．３５＜（１＋ｘ）／（ｙ＋ｖ＋ｗ）＜１．６５が好ましく、１．４５＜（１＋ｘ）／（ｙ＋ｖ＋ｗ）＜１．５５がより好ましい。この組成比が前記の範囲であれば、４．６Ｖ以上の高い充電電圧を印加した場合に、単位質量あたりの放電容量が高い正極材料が得られる。 As shown in the formula (I′-7), in the compound (I ′), the proportion of Li exceeds 1.2 times mol with respect to the total of transition metal elements Mn, Ni, and Co. Less than 8.
The composition ratio of the Li element to the total molar amount of the transition metal element is preferably 1.35 <(1 + x) / (y + v + w) <1.65, and 1.45 <(1 + x) / (y + v + w) <1.55. More preferred. When the composition ratio is in the above range, a positive electrode material having a high discharge capacity per unit mass can be obtained when a high charging voltage of 4.6 V or higher is applied.
　正極活物質としては、Ｌｉ（Ｌｉ０．１６Ｎｉ０．１７Ｃｏ０．０８Ｍｎ０．５９）Ｏ２、Ｌｉ（Ｌｉ０．１７Ｎｉ０．１７Ｃｏ０．１７Ｍｎ０．４９）Ｏ２、Ｌｉ（Ｌｉ０．１７Ｎｉ０．２１Ｃｏ０．０８Ｍｎ０．５４）Ｏ２、Ｌｉ（Ｌｉ０．１７Ｎｉ０．１４Ｃｏ０．１４Ｍｎ０．５５）Ｏ２、Ｌｉ（Ｌｉ０．１８Ｎｉ０．１２Ｃｏ０．１２Ｍｎ０．５８）Ｏ２、Ｌｉ（Ｌｉ０．１８Ｎｉ０．１６Ｃｏ０．１２Ｍｎ０．５４）Ｏ２、Ｌｉ（Ｌｉ０．２０Ｎｉ０．１２Ｃｏ０．０８Ｍｎ０．６０）Ｏ２、Ｌｉ（Ｌｉ０．２０Ｎｉ０．１６Ｃｏ０．０８Ｍｎ０．５６）Ｏ２、またはＬｉ（Ｌｉ０．２０Ｎｉ０．１３Ｃｏ０．１３Ｍｎ０．５４）Ｏ２が特に好ましい。 As the positive electrode active material, Li (Li 0.16 Ni 0.17 Co 0.08 Mn 0.59 ) O 2 , Li (Li 0.17 Ni 0.17 Co 0.17 Mn 0.49 ) O 2 , Li (Li 0.17 Ni 0.21 Co 0.08 Mn 0.54 ) O 2 , Li (Li 0.17 Ni 0.14 Co 0.14 Mn 0.55 ) O 2 , Li (Li 0.18 Ni 0.12 Co 0.12 Mn 0.58 ) O 2 , Li (Li 0.18 Ni 0.16 Co 0.12 Mn 0.54 ) O 2 , Li (Li 0.20 Ni 0.12 Co 0 .08 Mn 0.60 ) O 2 , Li (Li 0.20 Ni 0.16 Co 0.08 Mn 0.56 ) O 2 , or Li (Li 0.20 Ni 0.13 Co 0.13 Mn 0. 54 ) O 2 is particularly preferred.
　化合物（Ｉ）または化合物（Ｉ’）は、層状岩塩型結晶構造（空間群Ｒ－３ｍ）であることが好ましい。また、遷移金属元素に対するＬｉ元素の比率が高いため、Ｘ線源としてＣｕＫα線を用いるＸＲＤ（Ｘ線回折）測定では、層状Ｌｉ２ＭｎＯ３と同様に、２θ＝２０～２５°の範囲にピークが観察される。
　また、化合物（Ｉ）または化合物（Ｉ’）は、その表面をＡｌ、Ｙ、Ｇａ、Ｉｎ、Ｌａ、Ｐｒ、Ｎｄ、Ｇｄ、Ｄｙ、ＥｒおよびＹｂからなる群から選ばれる少なくとも１種の金属元素を含む金属酸化物、および／またはＬｉおよび非金属元素（Ｐ、Ｓ、Ｂ）を含む化合物により被覆されていてもよい。 Compound (I) or Compound (I ′) preferably has a layered rock salt type crystal structure (space group R-3m). In addition, since the ratio of Li element to transition metal element is high, XRD (X-ray diffraction) measurement using CuKα ray as an X-ray source has a peak in the range of 2θ = 20 to 25 °, similarly to layered Li 2 MnO 3. Is observed.
Further, the surface of the compound (I) or the compound (I ′) is at least one metal element selected from the group consisting of Al, Y, Ga, In, La, Pr, Nd, Gd, Dy, Er, and Yb. And / or a compound containing Li and a nonmetallic element (P, S, B).
　正極は、正極活物質と導電付与剤と結着剤を含む正極層が、集電体上に形成されてなる。導電付与剤としては、炭素材料の他、導電性酸化物の粉末等を使用することができる。結着剤としてはポリフッ化ビニリデン等の樹脂バインダーおよび／または炭化水素ゴムやフッ素ゴム等のゴム系バインダーを用いることができる。集電体としてはＡｌ等を主体とする金属薄膜を用いることができる。 The positive electrode is formed by forming a positive electrode layer containing a positive electrode active material, a conductivity-imparting agent, and a binder on a current collector. As the conductivity-imparting agent, in addition to a carbon material, a conductive oxide powder or the like can be used. As the binder, a resin binder such as polyvinylidene fluoride and / or a rubber binder such as hydrocarbon rubber or fluorine rubber can be used. As the current collector, a metal thin film mainly composed of Al or the like can be used.
　正極中の導電付与剤の含有量は、正極層全体の１～１０質量％が好ましく、結着剤の含有量も正極層全体の１～１０質量％程度が好ましい。導電付与剤と結着剤の割合が好ましい上限値以下であれば、正極層中の活物質の割合を充分に確保でき、単位質量あたりの充分な容量を得ることができる。導電付与剤と結着剤の割合が小さすぎると、導電性が保てなくなったり、電極剥離の問題が生じたりすることがある。正極層中の活物質の割合は、８０～９８質量％が好ましい。 The content of the conductivity-imparting agent in the positive electrode is preferably 1 to 10% by mass of the entire positive electrode layer, and the content of the binder is also preferably about 1 to 10% by mass of the entire positive electrode layer. When the ratio between the conductivity-imparting agent and the binder is equal to or less than the preferable upper limit value, the ratio of the active material in the positive electrode layer can be sufficiently secured, and a sufficient capacity per unit mass can be obtained. If the ratio between the conductivity-imparting agent and the binder is too small, the conductivity may not be maintained, or a problem of electrode peeling may occur. The proportion of the active material in the positive electrode layer is preferably 80 to 98% by mass.
［負極］
　負極は、粉末状の負極活物質と導電付与剤と結着剤を含む負極層が、集電体上に形成されてなる。負極に用いる負極活物質としては、リチウムイオンを充電時に吸蔵、放電時に放出することができれば、特に限定されるものでなく、公知のものを用いることができる。具体例としては、黒鉛、コークス、ハードカーボン等の炭素材料、リチウム－アルミニウム合金、リチウム－鉛合金、リチウム－錫合金等のリチウム合金、リチウム金属、Ｓｉ、ＳｎＯ２、ＳｎＯ、ＴｉＯ２、Ｎｂ２Ｏ２ＳｉＯ等の電位が正極活物質に比べて卑な金属酸化物が挙げられる。
　負極の結着剤および導電付与剤は、正極と同等のものが使用できる。集電体としてはＣｕ等を主体とする金属薄膜を用いることができる。
　なお、負極活物質が、それ自体で形状を保てる場合（例えばリチウム金属薄膜）は、負極活物質のみで負極を形成することができる。 [Negative electrode]
The negative electrode is formed by forming a negative electrode layer containing a powdered negative electrode active material, a conductivity-imparting agent, and a binder on a current collector. The negative electrode active material used for the negative electrode is not particularly limited as long as lithium ions can be occluded during charging and released during discharging, and known materials can be used. Specific examples include carbon materials such as graphite, coke, and hard carbon, lithium alloys such as lithium-aluminum alloy, lithium-lead alloy, and lithium-tin alloy, lithium metal, Si, SnO 2 , SnO, TiO 2 , and Nb 2. A metal oxide having a base potential lower than that of the positive electrode active material, such as O 2 SiO, can be used.
As the negative electrode binder and the conductivity-imparting agent, those equivalent to the positive electrode can be used. As the current collector, a metal thin film mainly composed of Cu or the like can be used.
In the case where the negative electrode active material can keep its shape by itself (for example, a lithium metal thin film), the negative electrode can be formed only with the negative electrode active material.
［非水電解液］
　非水電解液とは、水を実質的に含まない電解液であり、仮に水を含んでいたとしてもその水分量が該非水電解液を用いた二次電池の性能劣化が見られない範囲の量である電解液である。かかる非水電解液中に含まれうる水分量は、非水電解液の総質量に対して５００質量ｐｐｍ以下であることが好ましく、１００質量ｐｐｍ以下であることがより好ましく、５０質量ｐｐｍ以下であることが特に好ましい。水分量の下限値は、０質量ｐｐｍである。 [Non-aqueous electrolyte]
A non-aqueous electrolyte is an electrolyte that does not substantially contain water, and even if it contains water, the amount of water is in a range where performance degradation of a secondary battery using the non-aqueous electrolyte is not observed. The amount of electrolyte solution. The amount of water that can be contained in the non-aqueous electrolyte is preferably 500 ppm by mass or less, more preferably 100 ppm by mass or less, and 50 ppm by mass or less with respect to the total mass of the non-aqueous electrolyte. It is particularly preferred. The lower limit of the moisture content is 0 mass ppm.
　本発明における非水電解液は、ベース電解液と、後述の一般式（ＩＩ）で表わされる１種以上の化合物とからなる。また、ベース電解液は、以下に説明する１種以上の化合物（α）および１種以上のリチウム塩（β）を含有する。
　化合物（α）は、環状カーボネート化合物、鎖状カーボネート化合物、環状エステル化合物、および鎖状エステル化合物からなる群から選択される化合物である。
　化合物（α）が、ベース電解液に占める割合は、５０～９９．８質量％であることが好ましく、６０～９９．５質量％であることがより好ましく、７０～９９質量％であることが特に好ましい。
　化合物（α）のベース電解液に占める割合が好ましい下限値以上であれば、リチウム塩（β）を良好に溶解させることができる。また、好ましい上限値以下であれば、充分な量のリチウム塩（β）を含有させることができる。 The nonaqueous electrolytic solution in the present invention comprises a base electrolytic solution and one or more compounds represented by the general formula (II) described later. The base electrolyte contains one or more compounds (α) and one or more lithium salts (β) described below.
The compound (α) is a compound selected from the group consisting of a cyclic carbonate compound, a chain carbonate compound, a cyclic ester compound, and a chain ester compound.
The proportion of the compound (α) in the base electrolyte is preferably 50 to 99.8% by mass, more preferably 60 to 99.5% by mass, and 70 to 99% by mass. Particularly preferred.
When the proportion of the compound (α) in the base electrolyte is at least a preferred lower limit value, the lithium salt (β) can be dissolved well. Moreover, if it is below a preferable upper limit, sufficient quantity of lithium salt ((beta)) can be contained.
　環状カーボネート化合物とは、環骨格が炭素原子と酸素原子からなる環構造を有する化合物であり、該環構造が－Ｏ－Ｃ（＝Ｏ）－Ｏ－で表されるカーボネート結合を有する化合物である。
　環状カーボネート化合物における環構造は、４～１０員環が好ましく、４～７員環がより好ましく、入手容易な点から、５～６員環がさらに好ましく、５員環が特に好ましい。
　環状カーボネート化合物の環構造は、カーボネート結合を１つ有する環構造が好ましい。また、カーボネート結合が、直鎖アルキレン基またはビニレン基と連結して形成された環構造がより好ましい。 The cyclic carbonate compound is a compound in which the ring skeleton has a ring structure composed of carbon atoms and oxygen atoms, and the ring structure has a carbonate bond represented by —O—C (═O) —O—. .
The ring structure in the cyclic carbonate compound is preferably a 4- to 10-membered ring, more preferably a 4- to 7-membered ring, more preferably a 5- to 6-membered ring, and particularly preferably a 5-membered ring from the viewpoint of availability.
The ring structure of the cyclic carbonate compound is preferably a ring structure having one carbonate bond. In addition, a ring structure in which a carbonate bond is formed by linking with a linear alkylene group or vinylene group is more preferable.
　カーボネート結合が、直鎖アルキレン基と連結して形成された環構造を有するカーボネート化合物の場合、直鎖アルキレン基の炭素数は１～７が好ましく、１～４がより好ましく、２または３がさらに好ましく、２が特に好ましい。具体的には、プロピレンカーボネート（ＰＣ）、エチレンカーボネート（ＥＣ）が挙げられる。
　カーボネート結合が、ビニレン基と連結して形成された環構造を有するカーボネート化合物としては、ビニレンカーボネート、ジメチルビニレンカーボネートが挙げられ、ビニレンカーボネートが特に好ましい。 In the case of a carbonate compound having a cyclic structure formed by linking a carbonate bond to a linear alkylene group, the linear alkylene group preferably has 1 to 7 carbon atoms, more preferably 1 to 4, more preferably 2 or 3 2 is particularly preferable. Specific examples include propylene carbonate (PC) and ethylene carbonate (EC).
Examples of the carbonate compound having a ring structure in which a carbonate bond is linked to a vinylene group include vinylene carbonate and dimethyl vinylene carbonate, and vinylene carbonate is particularly preferable.
　また、環状カーボネート化合物は、前記直鎖アルキレン基の水素原子の１個以上を置換基で置換した化合物も好ましい。置換基としては、たとえば、ハロゲン原子、アルキル基、ハロゲン化アルキル基、ビニル基、またはアリル基が好ましい。具体的には、フルオロエチレンカーボネートが挙げられる。
　ベース電解液が環状カーボネート化合物を含有する場合には、環状カーボネート化合物は１種のみでもよく、２種以上であってもよい。環状カーボネート化合物を含有すると、非水電解液の誘電率を大きくすることができるので好ましい。 The cyclic carbonate compound is also preferably a compound in which one or more hydrogen atoms of the linear alkylene group are substituted with a substituent. As the substituent, for example, a halogen atom, an alkyl group, a halogenated alkyl group, a vinyl group, or an allyl group is preferable. Specific examples include fluoroethylene carbonate.
When the base electrolyte contains a cyclic carbonate compound, the cyclic carbonate compound may be only one type or two or more types. The inclusion of a cyclic carbonate compound is preferable because the dielectric constant of the non-aqueous electrolyte can be increased.
　鎖状カーボネート化合物とは、環構造を有さず、－Ｏ－Ｃ（＝Ｏ）－Ｏ－で表されるカーボネート結合を有する鎖状の化合物である。
　鎖状のカーボネート化合物は、カーボネート結合を１つ有する鎖状モノカーボネートが好ましい。鎖状モノカーボネートとしては、ジメチルカーボネート（ＤＭＣ）、エチルメチルカーボネート（ＥＭＣ）、ジエチルカーボネート（ＤＥＣ）が挙げられる。
　ベース電解液が鎖状カーボネート化合物を含有する場合には、鎖状カーボネート化合物は１種のみでもよく、２種以上であってもよい。鎖状カーボネート化合物を含有すると、非水電解液の粘度を低減できるので好ましい。 The chain carbonate compound is a chain compound having no carbonate structure and having a carbonate bond represented by —O—C (═O) —O—.
The chain carbonate compound is preferably a chain monocarbonate having one carbonate bond. Examples of the chain monocarbonate include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC).
When the base electrolyte contains a chain carbonate compound, the chain carbonate compound may be only one type or two or more types. It is preferable to contain a chain carbonate compound because the viscosity of the nonaqueous electrolytic solution can be reduced.
　環状エステル化合物とは、環骨格が炭素原子と酸素原子からなる環構造を有する化合物であり、該環構造が－Ｏ－Ｃ（＝Ｏ）－Ｃ－で表されるエステル結合を有する化合物である。
　環状エステル化合物は、分子内に炭素－炭素不飽和結合を含まない化合物であることが好ましい。環状エステル化合物における環構造は、４～１０員環が好ましく、４～７員環がより好ましく、入手容易な点から、５～６員環がさらに好ましく、５員環が特に好ましい。
　環状エステル化合物の環構造は、エステル結合を１つ有する環構造が好ましく、エステル結合が直鎖アルキレン基と連結して形成された環構造がより好ましい。直鎖アルキレン基の炭素数は１～７が好ましく、１～４がより好ましく、２または３がさらに好ましく、２が特に好ましい。また、環状エステル化合物は、前記直鎖アルキレン基の水素原子の１個以上を置換基で置換した化合物でもよい。置換基としては、たとえば、ハロゲン原子、アルキル基、ハロゲン化アルキル基等が挙げられる。 The cyclic ester compound is a compound in which the ring skeleton has a ring structure composed of a carbon atom and an oxygen atom, and the ring structure has an ester bond represented by —O—C (═O) —C—. .
The cyclic ester compound is preferably a compound that does not contain a carbon-carbon unsaturated bond in the molecule. The cyclic structure in the cyclic ester compound is preferably a 4- to 10-membered ring, more preferably a 4- to 7-membered ring, more preferably a 5- to 6-membered ring, and particularly preferably a 5-membered ring from the viewpoint of availability.
The ring structure of the cyclic ester compound is preferably a ring structure having one ester bond, and more preferably a ring structure formed by linking an ester bond with a linear alkylene group. The linear alkylene group preferably has 1 to 7 carbon atoms, more preferably 1 to 4, more preferably 2 or 3, and particularly preferably 2. Further, the cyclic ester compound may be a compound in which one or more hydrogen atoms of the linear alkylene group are substituted with a substituent. Examples of the substituent include a halogen atom, an alkyl group, and a halogenated alkyl group.
　具体例としては、γ－ブチロラクトン、γ－バレロラクトン、γ－ヘキサノラクトン、δ－バレロラクトン等の環状エステル化合物、および該環状エステル化合物の環構造を形成する炭素原子に結合する水素原子の１個以上が、ハロゲン原子、アルキル基、またはハロゲン化アルキル基に置換された化合物が挙げられる。なかでも、入手容易な点および電解液の性質の点から、γ－ブチロラクトン、またはγ－バレロラクトンが好ましく、γ－ブチロラクトンが特に好ましい。
　非水電解液が環状エステル化合物を含有する場合には、環状エステル化合物は１種のみでもよく、２種以上であってもよい。環状エステル化合物を含有すると、電解液の安定性が向上するので好ましい。 Specific examples include cyclic ester compounds such as γ-butyrolactone, γ-valerolactone, γ-hexanolactone, and δ-valerolactone, and one hydrogen atom bonded to the carbon atom forming the ring structure of the cyclic ester compound. Examples thereof include compounds in which at least one group is substituted with a halogen atom, an alkyl group, or a halogenated alkyl group. Among these, γ-butyrolactone or γ-valerolactone is preferable, and γ-butyrolactone is particularly preferable from the viewpoint of easy availability and properties of the electrolytic solution.
When the nonaqueous electrolytic solution contains a cyclic ester compound, the cyclic ester compound may be only one type or two or more types. The inclusion of a cyclic ester compound is preferable because the stability of the electrolytic solution is improved.
　鎖状エステル化合物とは、環構造を有さず、－Ｏ－Ｃ（＝Ｏ）－Ｃ－で表されるエステル結合を有する鎖状の化合物である。
　鎖状のエステル化合物は、エステル結合を１つ有する鎖状モノエステルが好ましい。鎖状モノエステルとしては、酢酸エチル、酪酸エチル、酢酸ブチル等が挙げられる。
　ベース電解液が鎖状エステル化合物を含有する場合には、鎖状エステル化合物は１種のみでもよく、２種以上であってもよい。鎖状エステル化合物を含有すると、電解液の粘度を低減しやすいので好ましい。 The chain ester compound is a chain compound that has no ring structure and has an ester bond represented by —O—C (═O) —C—.
The chain ester compound is preferably a chain monoester having one ester bond. Examples of the chain monoester include ethyl acetate, ethyl butyrate, butyl acetate and the like.
When the base electrolyte contains a chain ester compound, the chain ester compound may be only one type or two or more types. It is preferable to include a chain ester compound because the viscosity of the electrolytic solution can be easily reduced.
　ベース電解液は、環状カーボネート化合物、鎖状カーボネート化合物、環状エステル化合物、鎖状エステル化合物のいずれか二種以上を含有してもよい。四種総てを含有してもよい。
　ベース電解液は、下記化合物（１）、化合物（２）、および化合物（３）からなる群から選択される１種以上の化合物（α’）を含んでいることが好ましい。 The base electrolyte may contain any two or more of a cyclic carbonate compound, a chain carbonate compound, a cyclic ester compound, and a chain ester compound. You may contain all four types.
The base electrolyte solution preferably contains one or more compounds (α ′) selected from the group consisting of the following compound (1), compound (2), and compound (3).
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　式（１）～（３）において、Ｒ1～Ｒ１2は、それぞれ独立に水素原子、ハロゲン原子、アルキル基、またはハロゲン化アルキル基であり、Ｘは酸素原子またはＣＨ２である。）
　Ｒ1～Ｒ１2がハロゲン原子である場合、各々独立にフッ素原子または塩素原子であることが好ましい。Ｒ1～Ｒ１2がアルキル基である場合、アルキル基の炭素数は１～６であることが好ましい。Ｒ1～Ｒ１2がハロゲン化アルキル基である場合、アルキル基の炭素数は１～６であることが好ましく、ハロゲン原子としては、フッ素原子、または塩素原子が好ましい。 In formulas (1) to (3), R 1 to R 12 are each independently a hydrogen atom, a halogen atom, an alkyl group, or a halogenated alkyl group, and X is an oxygen atom or CH 2 . )
When R 1 to R 12 are halogen atoms, each is preferably independently a fluorine atom or a chlorine atom. When R 1 to R 12 are alkyl groups, the alkyl group preferably has 1 to 6 carbon atoms. When R 1 to R 12 are halogenated alkyl groups, the alkyl group preferably has 1 to 6 carbon atoms, and the halogen atom is preferably a fluorine atom or a chlorine atom.
　化合物（α’）が、ベース電解液に占める割合、すなわち、化合物（１）、化合物（２）、および化合物（３）の合計量がベース電解液に占める割合は、５０～９９．８質量％であることが好ましく、６０～９９．５質量％であることがより好ましく、７０～９９質量％であることが特に好ましい。
　化合物（１）、化合物（２）、および化合物（３）の各々が、化合物（α’）全体に占める割合は、化合物（１）が５～１００質量％、化合物（２）が０～９５質量％、化合物（３）が０～１０質量％であることが好ましく、化合物（１）が１０～１００質量％、化合物（２）が０～９０質量％、化合物（３）が０～５質量％であることがさらに好ましく、化合物（１）が２０～１００質量％、化合物（２）が０～８０質量％、化合物（３）が０～３質量％であることが特に好ましい。 The proportion of the compound (α ′) in the base electrolyte solution, that is, the proportion of the total amount of the compound (1), the compound (2) and the compound (3) in the base electrolyte solution is 50 to 99.8% by mass. It is preferably 60 to 99.5% by mass, more preferably 70 to 99% by mass.
The ratio of each of the compound (1), the compound (2), and the compound (3) to the entire compound (α ′) is 5 to 100 mass% for the compound (1) and 0 to 95 mass for the compound (2). The compound (3) is preferably 0 to 10% by mass, the compound (1) is 10 to 100% by mass, the compound (2) is 0 to 90% by mass, and the compound (3) is 0 to 5% by mass. More preferably, the compound (1) is 20 to 100% by mass, the compound (2) is 0 to 80% by mass, and the compound (3) is particularly preferably 0 to 3% by mass.
　リチウム塩（β）は、ＬｉＰＦ６、ＬｉＣｌＯ４、ＬｉＢＦ４、下記化合物（Ａ）（ただし、ｋは１～５の整数である。）、下記化合物（Ｂ）、下記化合物（Ｃ）、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＣＯ３、ＬｉＣ（ＣＦ３ＳＯ２）３、およびＬｉＮ（ＣＦ３ＳＯ２）２からなる群から選択されるリチウム塩である。 The lithium salt (β) is LiPF 6 , LiClO 4 , LiBF 4 , the following compound (A) (where k is an integer of 1 to 5), the following compound (B), the following compound (C), LiCF 3. A lithium salt selected from the group consisting of SO 3 , LiC 4 F 9 CO 3 , LiC (CF 3 SO 2 ) 3 , and LiN (CF 3 SO 2 ) 2 .
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　化合物（Ａ）としては、たとえば、下記化合物（Ａ－１）～化合物（Ａ－４）が挙げられる。伝導度の高い非水電解液が得られやすい点から、化合物（Ａ）としては、ｋが２の化合物（Ａ－２）を含むことが好ましく、ｋが２の化合物（Ａ－２）からなることがより好ましい。 Examples of the compound (A) include the following compound (A-1) to compound (A-4). The compound (A) preferably includes a compound (A-2) in which k is 2, and is composed of a compound (A-2) in which k is 2, from the viewpoint of easily obtaining a non-aqueous electrolyte with high conductivity. It is more preferable.
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
　ベース電解液における前記リチウム塩（β）の濃度は、０．５ｍｏｌ／ｌ～１．５ｍｏｌ／ｌとすることが好ましい。質量に換算すると、５～５０質量％が好ましく、８～３０質量％がより好ましく、１０～２０質量％がさらに好ましい。この濃度が高すぎると粘度が増加し、濃度が低すぎると電気伝導率が低下する。
　リチウム塩（β）は、ベース電解液に溶解していることが好ましい。 The concentration of the lithium salt (β) in the base electrolyte is preferably 0.5 mol / l to 1.5 mol / l. In terms of mass, it is preferably 5 to 50% by mass, more preferably 8 to 30% by mass, and further preferably 10 to 20% by mass. If this concentration is too high, the viscosity increases, and if the concentration is too low, the electrical conductivity decreases.
The lithium salt (β) is preferably dissolved in the base electrolyte.
　ベース電解液は、上記以外の従来の非水電解液用溶媒を含有してもよい。例えば、１，２－ジメトキシエタン（ＤＭＥ）、１、２－ジエトキシエタン（ＤＥＥ）、エトキシメトキシエタン（ＥＭＥ）等の鎖状エーテル類、テトラヒドロフラン、２－メチルテトラヒドロフラン等の環状エーテル類、ジメチルスルホキシド、ホルムアミド、アセトアミド、ジメチルホルムアミド、ジオキソラン、アセトニトリル、プロピルニトリル、ニトロメタン、エチルモノグライム、リン酸トリエステル、トリメトキシメタン、ジオキソラン誘導体、スルホラン、メチルスルホラン、１、３－ジメチル－２－イミダゾリジノン、３－メチル－２－オキサゾリジノン、エチレンカーボネート誘導体、プロピレンカーボネート誘導体、テトラヒドロフラン誘導体、エチルエーテル、アニソール、Ｎ－メチルピロリドン、等が挙げられる。 The base electrolyte may contain a conventional nonaqueous electrolyte solvent other than those described above. For example, chain ethers such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE) and ethoxymethoxyethane (EME), cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran, dimethyl sulfoxide , Formamide, acetamide, dimethylformamide, dioxolane, acetonitrile, propyl nitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, Examples include 3-methyl-2-oxazolidinone, ethylene carbonate derivatives, propylene carbonate derivatives, tetrahydrofuran derivatives, ethyl ether, anisole, N-methylpyrrolidone, and the like.
　本発明の非水電解液は、式（ＩＩ）で表される１種以上の化合物を含有する。
　ただし、式（ＩＩ）において、Ｒｆ１、Ｒｆ２は、それぞれ独立にエーテル性酸素原子を含んでもよい炭素数１から４のパーフルオロアルキル基であり、Ｙ１、Ｙ２は、それぞれ独立にハロゲン原子もしくは水素原子である。 The nonaqueous electrolytic solution of the present invention contains one or more compounds represented by the formula (II).
However, in the formula (II), Rf 1 and Rf 2 are each independently a C 1 to C 4 perfluoroalkyl group which may contain an etheric oxygen atom, and Y 1 and Y 2 are each independently a halogen atom. An atom or a hydrogen atom.
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　式（ＩＩ）において、Ｒｆ１、Ｒｆ２は互いに同一であることか好ましく、Ｙ１、Ｙ２も互いに同一であることか好ましい。
　Ｒｆ１、Ｒｆ２は、いずれもトリフルオロメチル基であり、Ｙ１、Ｙ２は、それぞれ独立に水素原子またはフッ素原子であることが好ましい。
　化合物（ＩＩ）は１種のみでもよく、２種以上であってもよい。本発明では、非水電解液が化合物（ＩＩ）を含有することにより、高電圧で充放電を行っても、平均放電電圧の低下が抑制されることによりエネルギー密度を維持することができる。
　非水電解液における化合物（ＩＩ）の含有量は、ベース電解液１００質量部に対して、０．２～１０．０質量部であることが好ましく、０．５～５．０質量部であることがより好ましい。
　化合物（ＩＩ）の含有量が好ましい下限値以上であれば、良好な高電位の充放電サイクル特性を得ることが容易となる。化合物（ＩＩ）の含有量が好ましい上限値以下であれば、伝導度や低温特性等電解液の諸特性を高い水準で両立することができる。 In Formula (II), Rf 1 and Rf 2 are preferably the same as each other, and Y 1 and Y 2 are also preferably the same as each other.
Rf 1 and Rf 2 are both trifluoromethyl groups, and Y 1 and Y 2 are preferably each independently a hydrogen atom or a fluorine atom.
Only one type of compound (II) may be used, or two or more types may be used. In the present invention, when the nonaqueous electrolyte contains compound (II), the energy density can be maintained by suppressing the decrease in the average discharge voltage even when charging and discharging are performed at a high voltage.
The content of compound (II) in the non-aqueous electrolyte is preferably 0.2 to 10.0 parts by mass, and 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the base electrolyte. It is more preferable.
When the content of compound (II) is at least the preferred lower limit, it becomes easy to obtain good high potential charge / discharge cycle characteristics. When the content of the compound (II) is not more than the preferable upper limit value, various characteristics of the electrolytic solution such as conductivity and low temperature characteristics can be achieved at a high level.
［セパレータ］
　セパレータとしての多孔膜の材質および形状は、非水電解液に対して安定であり、かつ保液性に優れていれば特に制限はなく、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、エチレンとテトラフルオロエチレンのコポリマー等のフッ素樹脂、ポリイミド、またはポリエチレン、ポリプロピレン等のポリオレフィンを原料とする多孔性シートまたは不織布が好ましく、材質はポリエチレン、ポリプロピレン等のポリオレフィンが好ましい。また、これらの多孔膜に非水電解液を含浸させてゲル化させたものをゲル電解質として用いてもよい。 [Separator]
The material and shape of the porous membrane as the separator are not particularly limited as long as it is stable with respect to the non-aqueous electrolyte and has excellent liquid retention properties. Polyvinylidene fluoride, polytetrafluoroethylene, ethylene and tetrafluoroethylene A porous sheet or non-woven fabric made of a fluororesin such as a copolymer, polyimide, or a polyolefin such as polyethylene or polypropylene is preferred, and the material is preferably a polyolefin such as polyethylene or polypropylene. Moreover, you may use what impregnated these porous membranes with the nonaqueous electrolyte solution and gelatinized it as a gel electrolyte.
　本発明に係るリチウム二次電池は、例えば、乾燥空気または不活性ガス雰囲気において、負極および正極を、セパレータを介して積層し、あるいは積層したものを捲回した後に、缶ケース等の外装容器に収容し、電解液を注入し、合成樹脂と金属箔との積層体等からなる可とう性フィルム等によって封口することによって電池を製造することができる。 The lithium secondary battery according to the present invention is, for example, laminated in a dry air or an inert gas atmosphere by laminating a negative electrode and a positive electrode via a separator, or winding the laminated one, and then in an outer container such as a can case. A battery can be manufactured by housing, injecting an electrolytic solution, and sealing with a flexible film made of a laminate of a synthetic resin and a metal foil.
　電池の構成・形状は、特に制限がなく、セパレータを挟んで対向した正極、負極を捲回した捲回型、積層型等の形態をとることができ、また、コイン型、ラミネートパック、角型セル、円筒型セル等の形態をとることができる。
　本発明に係るリチウム二次電池の充電電圧は、４．２Ｖ以上が好ましく、４．４Ｖ以上がより好ましく、４．５Ｖ以上が特に好ましい。また、５．０Ｖ以下が好ましく、４．９Ｖ以下がより好ましく、４．８Ｖ以下が特に好ましい。 The configuration and shape of the battery is not particularly limited, and can take the form of a positive electrode facing the separator, a wound type wound with the negative electrode, a laminated type, etc., and a coin type, laminate pack, square type, etc. It can take the form of a cell, a cylindrical cell or the like.
The charging voltage of the lithium secondary battery according to the present invention is preferably 4.2 V or higher, more preferably 4.4 V or higher, and particularly preferably 4.5 V or higher. Moreover, 5.0V or less is preferable, 4.9V or less is more preferable, and 4.8V or less is especially preferable.
［試験電解液の調製］
　エチレンカーボネートとジエチルカーボネートを等容量で混合したカーボネート系溶媒に、１Ｍの濃度（１ｍｏｌＬｉＰＦ６／ｌ（リットル）電解液）になるようにＬｉＰＦ６を溶解し、参照例の試験電解液とした。
　この参照例の試験電解液に対して、特定の添加剤を特定の割合で添加して、各実施例、比較例の試験電解液とした。各実施例、比較例の試験電解液における添加剤の種類と添加量（参照例の試験電解液を１００質量部とする。）を表１に示す。
　なお、表１における化合物（ＩＩ－１）は、化式（ＩＩ－１）に示す化合物である。 [Preparation of test electrolyte]
LiPF 6 was dissolved in a carbonate-based solvent in which ethylene carbonate and diethyl carbonate were mixed in an equal volume so as to have a concentration of 1M (1 mol LiPF 6 / l (liter) electrolytic solution) to obtain a test electrolytic solution of a reference example.
With respect to the test electrolyte solution of this reference example, a specific additive was added at a specific ratio to obtain test electrolyte solutions of Examples and Comparative Examples. Table 1 shows the types and amounts of additives in the test electrolytes of the examples and comparative examples (the test electrolyte of the reference example is 100 parts by mass).
In addition, the compound (II-1) in Table 1 is a compound represented by the chemical formula (II-1).
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
［評価用セルの作製］
　正極活物質としてＬｉ（Ｌｉ０．２Ｎｉ０．１２８Ｃｏ０．１３４Ｍｎ０．５３８）Ｏ２　４．４８ｇと、導電付与剤であるアセチレンブラック０．５６ｇと、結着剤であるポリフッ化ビニリデン（ＰＶｄＦ）を１２質量％を含有するＮ－メチルピロリドン（ＮＭＰ）溶液１２．５５ｇとを混合し、スラリー化したものを厚さ２０μｍのアルミニウム箔上に塗工し、乾燥、プレスしたものを直径１８ｍｍの円形に打ち抜いたものを正極とした。また、厚さ３００μｍのリチウム金属箔を直径１９ｍｍの円形に打ち抜いたものを負極とした。セパレータとして厚さ２０μｍのポリオレフィン系微多孔膜を前記正極と負極の間に存在せしめ、そこに各試験電解液を０．５ｍＬ添加し、評価用セルを作成した。 [Production of evaluation cell]
4.48 g of Li (Li 0.2 Ni 0.128 Co 0.134 Mn 0.538 ) O 2 as a positive electrode active material, 0.56 g of acetylene black as a conductivity-imparting agent, and polyvinylidene fluoride as a binder (PVdF) was mixed with 12.55 g of an N-methylpyrrolidone (NMP) solution containing 12% by mass, and the slurry was applied onto an aluminum foil having a thickness of 20 μm, dried and pressed to obtain a diameter. A positive electrode was punched into an 18 mm circle. A negative electrode was prepared by punching a lithium metal foil having a thickness of 300 μm into a circle having a diameter of 19 mm. As a separator, a polyolefin microporous film having a thickness of 20 μm was present between the positive electrode and the negative electrode, and 0.5 mL of each test electrolyte was added thereto to prepare an evaluation cell.
［充放電サイクル試験］
　評価用セルを充放電機に接続し、１サイクル目は２０ｍＡ／ｇの電流量で４．６Ｖ（リチウム金属に対する電圧。以下同様。）まで定電流充電を行った後、さらに４．６Ｖの定電圧で２３時間充電を行い、充電後１０分間休止後、２０ｍＡ／ｇの電流で２．０Ｖに達するまで定電流放電を行った。２サイクル目以降は、２００ｍＡ／ｇの電流量で４．６Ｖまで定電流充電を行った後、さらに４．６Ｖの定電圧で４時間充電を行い、充電後１０分休止後、１００ｍＡ／ｇの電流量で２．０Ｖに達するまで定電流放電を行った。そして、１０分間の休止の後に次のサイクルの充放電を開始するようにして、最大８０回の充放電サイクル試験を実施した。 [Charge / discharge cycle test]
The evaluation cell was connected to the charger / discharger, and in the first cycle, constant current charging was performed at a current amount of 20 mA / g to 4.6 V (voltage against lithium metal; the same shall apply hereinafter), and then a constant voltage of 4.6 V was applied. The battery was charged at a voltage for 23 hours, rested for 10 minutes after charging, and then discharged at a constant current of 20 mA / g until reaching 2.0V. After the second cycle, the battery was charged at a constant current of up to 4.6 V at a current amount of 200 mA / g, then charged at a constant voltage of 4.6 V for 4 hours, paused for 10 minutes after charging, and then 100 mA / g. Constant current discharge was performed until the current reached 2.0V. Then, a charge / discharge cycle test of a maximum of 80 times was performed such that the charge / discharge of the next cycle was started after a pause of 10 minutes.
　８０回に至る前に放電容量維持率の著しい低下が見られた場合は、その時点で充放電サイクル試験を中止した。充放電サイクル試験中止時点のサイクル数を表１に示す。また、８０サイクル完了時点、または途中で中止した場合には充放電サイクル試験中止時点の放電容量の、５サイクル目の放電容量に対する比率を放電容量維持率として表１に示す。
　また、参照例と実施例１については、８０サイクル完了時点の平均放電電圧の５サイクル目の平均放電電圧に対する比率を平均放電電圧維持率として表２に示す。
　また、参照例と実施例１については、８０サイクル完了時点の放電エネルギーの５サイクル目の放電エネルギーに対する比率を放電エネルギー維持率として表３に示す。放電エネルギーは放電容量と平均放電電圧との積で表わされる数値であり、数値が大きいほど該非水電解液二次電池が行うことのできる仕事量が大きいことを意味する。 If a significant decrease in the discharge capacity retention rate was observed before reaching 80 times, the charge / discharge cycle test was stopped at that time. Table 1 shows the number of cycles when the charge / discharge cycle test was stopped. Further, Table 1 shows the ratio of the discharge capacity at the time when the charge / discharge cycle test is stopped to the discharge capacity at the fifth cycle as the discharge capacity maintenance ratio when the 80 cycles are completed or when it is stopped halfway.
For the reference example and Example 1, Table 2 shows the ratio of the average discharge voltage at the completion of 80 cycles to the average discharge voltage at the fifth cycle as the average discharge voltage maintenance ratio.
Moreover, about a reference example and Example 1, Table 3 shows the ratio with respect to the discharge energy of the 5th cycle of the discharge energy at the time of 80th cycle completion as a discharge energy maintenance factor. The discharge energy is a numerical value represented by the product of the discharge capacity and the average discharge voltage. The larger the numerical value, the larger the work that can be performed by the nonaqueous electrolyte secondary battery.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　表１、表２に示すように、実施例１では、８０サイクル目において、放電容量維持率、平均放電電圧ともに高い値が得られた。それにより表３に示すように、放電エネルギー維持率も高い値が得られた。 As shown in Tables 1 and 2, in Example 1, high values were obtained for both the discharge capacity retention ratio and the average discharge voltage at the 80th cycle. As a result, as shown in Table 3, a high discharge energy maintenance rate was obtained.
　本発明の非水電解液二次電池は、高電圧で充電し、高容量を得ることが可能であり、モータ駆動用の車載電源として利用できる。
　なお、２０１１年１１月１１日に出願された日本特許出願２０１１－２４７６４０号の明細書、特許請求の範囲、及び要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。 The non-aqueous electrolyte secondary battery of the present invention can be charged at a high voltage to obtain a high capacity, and can be used as a vehicle-mounted power source for driving a motor.
It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2011-247640 filed on November 11, 2011 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (7)

  1. 　一般式（Ｉ）で表わされる化合物を正極活物質とする正極と、負極と、非水電解液と、を有し、
    　前記非水電解液は、
    環状カーボネート化合物、鎖状カーボネート化合物、環状エステル化合物、および鎖状エステル化合物からなる群から選択される１種以上の化合物（α）と、ＬｉＰＦ６、ＬｉＣｌＯ４、ＬｉＢＦ４、一般式（Ａ）で表される化合物、一般式（Ｂ）で表される化合物、一般式（Ｃ）で表される化合物、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＣＯ２、ＬｉＣ（ＣＦ３ＳＯ２）３、およびＬｉＮ（ＣＦ３ＳＯ２）２からなる群から選択される１種以上のリチウム塩（β）と、を含むベース電解液と、一般式（ＩＩ）で表わされる１種以上の化合物と、を含有することを特徴とする非水電解液二次電池。
    　Ｌｉ（ＬｉｘＭｎｙＭｅ´ｚ）ＯｐＦｑ　…………（Ｉ）
    Figure JPOXMLDOC01-appb-C000001
     　ただし、式（Ｉ）において、Ｍｅ´は、Ｃｏ、Ｎｉ、Ｃｒ、Ｆｅ、Ａｌ、Ｔｉ、ＺｒおよびＭｇからなる群から選ばれる少なくとも１種である。
    　また、０．０９＜ｘ＜０．３、ｙ＞０、ｚ＞０、１．９＜ｐ＜２．１、０≦ｑ≦０．１であり、かつ０．４≦ｙ／（ｙ＋ｚ）≦０．８、ｘ＋ｙ＋ｚ＝１、１．２＜（１＋ｘ）／（ｙ＋ｚ）である。
    　また、式（Ａ）において、ｋは１～５の整数である。
    　また、式（ＩＩ）において、Ｒｆ１、Ｒｆ２は、それぞれ独立にエーテル性酸素原子を含んでもよい炭素数１から４のパーフルオロアルキル基であり、Ｙ１、Ｙ２は、それぞれ独立にハロゲン原子もしくは水素原子である。     A positive electrode having a compound represented by the general formula (I) as a positive electrode active material, a negative electrode, and a non-aqueous electrolyte;
    The non-aqueous electrolyte is
    One or more compounds (α) selected from the group consisting of a cyclic carbonate compound, a chain carbonate compound, a cyclic ester compound, and a chain ester compound, and LiPF 6 , LiClO 4 , LiBF 4 , and the general formula (A) Compounds represented by general formula (B), compounds represented by general formula (C), LiCF 3 SO 3 , LiC 4 F 9 CO 2 , LiC (CF 3 SO 2 ) 3 , and LiN A base electrolyte containing one or more lithium salts (β) selected from the group consisting of (CF 3 SO 2 ) 2 and one or more compounds represented by the general formula (II) A non-aqueous electrolyte secondary battery.
    Li (Li x Mn y Me' z ) O p F q ............ (I)
    Figure JPOXMLDOC01-appb-C000001
     However, in the formula (I), Me ′ is at least one selected from the group consisting of Co, Ni, Cr, Fe, Al, Ti, Zr and Mg.
    Further, 0.09 <x <0.3, y> 0, z> 0, 1.9 <p <2.1, 0 ≦ q ≦ 0.1, and 0.4 ≦ y / (y + z) ≦ 0.8, x + y + z = 1, 1.2 <(1 + x) / (y + z).
    In the formula (A), k is an integer of 1 to 5.
    In Formula (II), Rf 1 and Rf 2 are each independently a C 1 to C 4 perfluoroalkyl group that may contain an etheric oxygen atom, and Y 1 and Y 2 are each independently a halogen atom. An atom or a hydrogen atom.
  2. 　式（ＩＩ）で表わされる化合物のＲｆ１、Ｒｆ２が、いずれもトリフルオロメチル基であり、Ｙ１、Ｙ２は、それぞれ独立に水素原子またはフッ素原子である請求項１に記載の非水電解液二次電池。 The non-aqueous solution according to claim 1 , wherein Rf 1 and Rf 2 of the compound represented by the formula (II) are both trifluoromethyl groups, and Y 1 and Y 2 are each independently a hydrogen atom or a fluorine atom. Electrolyte secondary battery.
  3. 　非水電解液における式（ＩＩ）で表わされる化合物の含有量が、ベース電解液１００質量部に対して、０．２～１０．０質量部である請求項１または２に記載の非水電解液二次電池。 The nonaqueous electrolysis according to claim 1 or 2, wherein the content of the compound represented by the formula (II) in the nonaqueous electrolytic solution is 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the base electrolytic solution. Liquid secondary battery.
  4. 　前記ベース電解液に占める前記化合物（α）の割合が、５０～９９．８質量％である請求項１～３のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein a ratio of the compound (α) to the base electrolyte is 50 to 99.8 mass%.
  5. 　前記ベース電解液における前記リチウム塩（β）の濃度が、０．５ｍｏｌ／ｌ～１．５ｍｏｌ／ｌである請求項１～４のいずれか一項に記載の非水電解液二次電池。 The nonaqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the concentration of the lithium salt (β) in the base electrolyte is 0.5 mol / l to 1.5 mol / l.
  6. 　式（Ｉ）で表される化合物が下式（Ｉ’）で表される化合物である請求項１～５のいずれか一項に記載の非水電解液二次電池。
    　Ｌｉ（ＬｉｘＭｎｙＮｉｖＣｏｗ）Ｏｐ　…………（Ｉ’）
    　ただし、式（Ｉ’）において、０．０９＜ｘ＜０．３、０．３６＜ｙ＜０．７３、０＜ｖ＜０．３２、０＜ｗ＜０．３２、１．９＜ｐ＜２．１、ｘ＋ｙ＋ｖ＋ｗ＝１、１．２＜（１＋ｘ）／（ｙ＋ｖ＋ｗ）＜１．８である。     The non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein the compound represented by the formula (I) is a compound represented by the following formula (I ').
    Li (Li x Mn y Ni v Co w) O p ............ (I ')
    However, in the formula (I ′), 0.09 <x <0.3, 0.36 <y <0.73, 0 <v <0.32, 0 <w <0.32, 1.9 <p <2.1, x + y + v + w = 1, 1.2 <(1 + x) / (y + v + w) <1.8.
  7. 　充電電圧を４．４Ｖ以上として用いる請求項１～６のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 6, wherein the charging voltage is 4.4V or higher.
PCT/JP2012/079180 2011-11-11 2012-11-09 Non-aqueous electrolyte secondary cell WO2013069791A1 (en)

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WO2014034409A1 (en) * 2012-08-28 2014-03-06 住友電気工業株式会社 Molten salt battery, method for manufacturing same, and apparatus for producing battery element for molten salt batteries
CN113851723A (en) * 2020-06-28 2021-12-28 深圳新宙邦科技股份有限公司 Electrolyte and metal-sulfur battery

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WO2008081839A1 (en) * 2006-12-27 2008-07-10 Sanyo Electric Co., Ltd. Nonaqueous electrolyte secondary battery and method for production thereof
JP2009038036A (en) * 2006-09-29 2009-02-19 Mitsui Mining & Smelting Co Ltd Adjustment method for nonaqueous electrolyte secondary battery
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JP2007242581A (en) * 2006-02-08 2007-09-20 Sanyo Electric Co Ltd Nonaqueous electrolyte secondary battery
JP2009038036A (en) * 2006-09-29 2009-02-19 Mitsui Mining & Smelting Co Ltd Adjustment method for nonaqueous electrolyte secondary battery
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JP2010086690A (en) * 2008-09-30 2010-04-15 Gs Yuasa Corporation Active material for lithium secondary battery, lithium secondary battery, and manufacturing method of thereof

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014034409A1 (en) * 2012-08-28 2014-03-06 住友電気工業株式会社 Molten salt battery, method for manufacturing same, and apparatus for producing battery element for molten salt batteries
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