Non-aqueous electrolyte and non-aqueous electrolyte secondary battery using the same

Abstract

Provided are a novel non-aqueous electrolyte capable of suppressing an increase in initial resistance, and a non-aqueous electrolyte secondary battery using the same. The non-aqueous electrolyte contains (I) a compound represented by general formula [1a], (II) a solute, and (III). The non-aqueous electrolyte secondary battery contains the non-aqueous electrolyte.　[1a]: M+[X-S(=O)2-N-C(=O)-R]- (In general formula [1a], X represents a halogen atom, R represents a -CN group or -OCN group, and M+ represents an alkali metal ion.)

Description

[Technical Field]

[0001] The present disclosure relates to a nonaqueous electrolyte solution and a nonaqueous electrolyte secondary battery using the same. [Background technology]

[0002] To date, optimization of various battery components, including the active materials of the positive and negative electrodes, has been investigated as a means to improve the durability of non-aqueous electrolyte secondary batteries. Non-aqueous electrolytes are no exception, and it has been proposed to use various additives to form a solid electrolyte interface (SEI) at the interface between the electrode and the electrolyte, thereby suppressing degradation due to electrolyte decomposition on the surface of the active positive and negative electrodes.

[0003] For example, Patent Document 1 discloses a nonaqueous electrolyte solution for lithium batteries that can be used to construct lithium batteries with excellent battery characteristics such as cycle characteristics, battery capacity, storage characteristics, and conductivity. The nonaqueous electrolyte solution is characterized in that the nonaqueous electrolyte solution contains an electrolyte dissolved in a nonaqueous solvent and further contains a nitrile compound and an S═O group-containing compound. It is also disclosed that when a dinitrile compound is used as the nitrile compound, it is also preferable to use it without combining it with an S=O group-containing compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-266825 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the present inventors have found that when a nonaqueous electrolyte containing a nitrile compound as described in Patent Document 1 is used, the elution of the copper component, which is the metal of the negative electrode current collector, into the electrolyte during overdischarge can be reduced, possibly because a protective coating that inhibits corrosion is formed on the metal surface, but there is a problem in that the initial resistance increases. Therefore, an object of the present invention is to provide a novel non-aqueous electrolyte solution that can suppress an increase in initial resistance, and a non-aqueous electrolyte secondary battery using the same. [Means for solving the problem]

[0006] As a result of intensive research in view of the above problems, the present inventors have found that an increase in initial resistance can be suppressed by using a nitrile compound having a specific structure in a nonaqueous electrolyte solution containing a solute and a nonaqueous organic solvent, and have arrived at the present invention. That is, the present inventors have found that the above object can be achieved by the following configuration.

[0007] [1] (I) a compound represented by the following general formula [1a], (II) a solute; (III) a nonaqueous organic solvent; A non-aqueous electrolyte solution containing: M + [XS(=O)2-NC(=O)-R] - [1a] (In the general formula [1a], X represents a halogen atom, R represents a -CN group or an -OCN group, and M + represents an alkali metal ion. [2] The nonaqueous electrolyte solution according to the above [1], wherein X in the general formula [1a] is a fluorine atom. [3] The non-aqueous electrolyte solution according to the above [1] or [2], wherein the concentration of (I) is 0.01 to 5.00% by mass relative to the total amount of the electrolyte solution. [4] The non-aqueous electrolyte solution according to any one of the above [1] to [3], wherein (II) is at least one selected from the group consisting of LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiC4F9SO3, LiAlO2, LiAlCl4, LiCl, and LiI, or at least one selected from the group consisting of NaPF6, NaBF4, NaSbF6, NaAsF6, NaClO4, NaCF3SO3, NaC4F9SO3, NaAlO2, NaAlCl4, NaCl, and NaI. [5] The nonaqueous electrolyte solution according to any one of the above [1] to [4], wherein the (III) is at least one selected from the group consisting of cyclic esters, chain esters, cyclic ethers, chain ethers, sulfone compounds, sulfoxide compounds, and ionic liquids. [6] The nonaqueous electrolyte solution according to [5] above, wherein the (III) is a cyclic ester, and the cyclic ester is a cyclic carbonate. [7] The nonaqueous electrolyte solution according to [5] above, wherein the (III) is a chain ester, and the chain ester is a chain carbonate. [8] Furthermore, difluoro(oxalato)borates, bis(oxalato)borates, tetrafluoro(oxalato)phosphates, difluorobis(oxalato)phosphates, tris(oxalato)phosphates, difluorophosphates, fluorosulfonates, bis(fluorosulfonyl)imide salts, vinylene carbonate, vinylene carbonate oligomers (number average molecular weight in polystyrene equivalent: 170 to 5000), vinylethylene carbonate, fluoroethylene carbonate, 1,6-diisocyanatohexane, ethynylethylene carbonate, trans-difluoroethylene carbonate, propane sultone, propene sultone, 1,3,2-dioxathiolane-2,2-dioxide, 4-propyl- The non-aqueous electrolyte solution according to any one of the above [1] to [7], further comprising at least one additive selected from the group consisting of 1,3,2-dioxathiolane-2,2-dioxide, methylenemethane disulfonate, 1,2-ethanedisulfonic anhydride, methanesulfonyl fluoride, tris(trimethylsilyl)borate, (ethoxy)pentafluorocyclotriphosphazene, lithium tetrafluoro(malonato)phosphate, tetrafluoro(picolinato)phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,3-hexafluoroisopropyl)disiloxane, t-butylbenzene, t-amylbenzene, fluorobenzene, and cyclohexylbenzene. [9] The non-aqueous electrolyte solution according to any one of the above items [1] to [8], which is used in a non-aqueous electrolyte secondary battery having a current collector containing copper.

[10] A non-aqueous electrolyte secondary battery comprising at least a positive electrode, a negative electrode, a separator, and the non-aqueous electrolyte solution according to any one of the above items [1] to [9].

[11] The nonaqueous electrolyte secondary battery according to the above

[10] , wherein the negative electrode contains copper as a current collector. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a novel non-aqueous electrolyte solution that can suppress an increase in initial resistance, and a non-aqueous electrolyte secondary battery using the same. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present disclosure will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present disclosure, and the scope of the present disclosure is not limited to these specific details. Various modifications can be made within the scope of the gist of the present disclosure.

[0010] 1. Non-aqueous electrolyte The nonaqueous electrolyte solution of the present disclosure contains (I) a compound represented by the following general formula [1a], (II) a solute, and (III) a nonaqueous organic solvent. M + [XS(=O)2-NC(=O)-R] - [1a] (In the general formula [1a], X represents a halogen atom, R represents a -CN group or an -OCN group, and M + represents an alkali metal ion.

[0011] (I) Compounds represented by general formula [1a] The compound represented by the general formula [1a] is thought to partially decompose at the interface between the positive electrode and the electrolyte and at the interface between the negative electrode and the electrolyte to form a coating, which is presumed to prevent direct contact between the nonaqueous organic solvent or solute and the active material, thereby preventing decomposition of the nonaqueous organic solvent or solute and suppressing deterioration of battery performance. The mechanism by which the use of a compound represented by general formula [1a] in a non-aqueous electrolyte solution can suppress an increase in initial resistance when used in a non-aqueous electrolyte secondary battery is not clear, but the present inventors speculate as follows. As mentioned above, it is believed that the compound represented by the general formula [1a] partially decomposes at the interface between the positive electrode and the electrolyte solution and at the interface between the negative electrode and the electrolyte solution to form a coating. This coating not only prevents direct contact between the nonaqueous organic solvent or the solute and the active material, thereby preventing decomposition of the nonaqueous organic solvent or the solute, but also has cation conductivity for lithium ions, sodium ions, etc., and is therefore believed to suppress an increase in initial resistance.

[0012] In addition, This disclosure In the above, the initial resistance refers to the resistance of the cell after conditioning the cell under any conditions, and the smaller this resistance value, the better.

[0013] In the above general formula [1a], X represents a halogen atom. Examples of the halogen atom represented by X include a fluorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom is preferred from the viewpoint of lowering the battery resistance.

[0014] In the above general formula [1a], R represents a —CN group or a —OCN group.

[0015] In the above general formula [1a], M + represents an alkali metal ion. M + Examples of the alkali metal ion represented by the formula (I) include a lithium ion, a sodium ion, and a potassium ion, with a lithium ion or a sodium ion being preferred, a lithium ion being more preferred in the case of a lithium ion battery, and a sodium ion being more preferred in the case of a sodium ion battery.

[0016] Specific examples of the compound represented by the general formula [1a] include, but are not limited to, the following compounds: LiN(SO2F)(COCN) LiN(SO2F)(CO(OCN)) NaN(SO2F)(COCN) NaN(SO2F)(CO(OCN)) LiN(SO2Cl)(COCN) LiN(SO2Cl)(CO(OCN)) NaN(SO2Cl)(COCN) NaN(SO2Cl)(CO(OCN))

[0017] The compound represented by the general formula [1a] may be used alone or in combination of two or more.

[0018] The concentration of the compound represented by general formula [1a] in the non-aqueous electrolyte is preferably 0.01 to 5.00 mass% and more preferably 0.1 to 2.0 mass% relative to the total amount of the electrolyte. By setting the concentration of the compound represented by general formula [1a] to 0.01 mass% or more, the effect of suppressing an increase in initial resistance in a non-aqueous electrolyte secondary battery is easily achieved. Furthermore, by setting the concentration to 5.00 mass% or less, the coating formed on the electrode does not become too thick, which is unlikely to lead to an increase in resistance. The compound represented by the general formula [1a] can be produced by various methods, and the production method is not particularly limited. For example, a method of reacting a corresponding halogenated sulfonyl isocyanate with a corresponding cyanide salt or cyanate salt without a solvent or in a solvent that does not react with these may be mentioned.

[0019] (II) Solute Specific examples of the solute of the nonaqueous electrolyte solution of the present disclosure include, in the case of lithium batteries and lithium ion batteries, electrolyte salts typified by LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiC4F9SO3, LiAlO2, LiAlCl4, LiCl, LiI, LiC(CF3SO2)3, LiPF3(C3F7)3, LiB(CF3)4, LiBF3(C2F5), etc., and in the case of sodium ion batteries, electrolyte salts typified by NaPF6, NaBF4, NaSbF6, NaAsF6, NaClO4, NaCF3SO3, NaC4F9SO3, NaAlO2, NaAlCl4, NaCl, NaI, NaC(CF3SO2)3, NaPF3(C3F7)3, NaB(CF3)4, NaBF3(C2F5), etc. These solutes may be used singly or in any combination and ratio of two or more depending on the application. In the case of lithium batteries and lithium ion batteries, it is preferable that the electrolyte be at least one selected from the group consisting of LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiC4F9SO3, LiAlO2, LiAlCl4, LiCl, and LiI, and in the case of sodium ion batteries, it is preferable that the electrolyte be at least one selected from the group consisting of NaPF6, NaBF4, NaSbF6, NaAsF6, NaClO4, NaCF3SO3, NaC4F9SO3, NaAlO2, NaAlCl4, NaCl, and NaI.

[0020] Among these, in the case of lithium batteries and lithium ion batteries, it is preferable that the component (II) contains at least LiPF6, considering the energy density, output characteristics, lifespan, etc. of the battery. When LiPF6 is used in combination with other (II) components, it is preferable that the other (II) components be at least one selected from the group consisting of LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiC4F9SO3, LiAlO2, LiAlCl4, LiCl, and LiI.

[0021] In the case of a sodium ion battery, the component (II) preferably contains at least NaPF6. When NaPF6 is used in combination with other components (II), the other components (II) preferably include at least one selected from the group consisting of NaBF4, NaSbF6, NaAsF6, NaClO4, NaCF3SO3, NaC4F9SO3, NaAlO2, NaAlCl4, NaCl, and NaI.

[0022] (II) The concentration of the solute is not particularly limited, but the lower limit is preferably 0.5 mol / L or more, more preferably 0.7 mol / L or more, and even more preferably 0.9 mol / L or more, and the upper limit is preferably 2.5 mol / L or less, more preferably 2.0 mol / L or less, and even more preferably 1.5 mol / L or less.

[0023] The liquid temperature when dissolving the solute in the nonaqueous organic solvent is not particularly limited, but is preferably from -20 to 80°C, more preferably from 0 to 60°C.

[0024] (III) Non-aqueous organic solvents (III) The type of non-aqueous organic solvent is not particularly limited, and any non-aqueous organic solvent can be used. Specific examples include the following non-aqueous organic solvents: Examples of cyclic esters include cyclic carbonates such as propylene carbonate (hereinafter sometimes referred to as "PC"), ethylene carbonate (hereinafter sometimes referred to as "EC"), and butylene carbonate, as well as γ-butyrolactone and γ-valerolactone. Examples of chain esters include chain carbonates such as diethyl carbonate (hereinafter sometimes referred to as "DEC"), dimethyl carbonate (hereinafter sometimes referred to as "DMC"), and ethyl methyl carbonate (hereinafter sometimes referred to as "EMC"), as well as methyl acetate, methyl propionate, and ethyl propionate (hereinafter sometimes referred to as "EP"). Examples of cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, and dioxane. Examples of the chain ether include dimethoxyethane and diethyl ether. Other examples include sulfone compounds such as dimethyl sulfoxide and sulfolane, sulfoxide compounds, etc. Furthermore, ionic liquids and the like can also be used. The above (III) is preferably at least one selected from the group consisting of cyclic esters, chain esters, cyclic ethers, chain ethers, sulfone compounds, sulfoxide compounds, and ionic liquids. In one preferred embodiment, the above (III) contains a cyclic ester, and the cyclic ester is a cyclic carbonate.In another preferred embodiment, the above (III) contains a chain ester, and the chain ester is a chain carbonate.

[0025] The nonaqueous organic solvent used in the present disclosure may be a single type, or two or more types may be mixed in any combination and ratio depending on the application. Among these, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, methyl propionate, and ethyl propionate are particularly preferred from the viewpoints of electrochemical stability against oxidation-reduction and chemical stability related to heat and reactions with the solute.

[0026] For example, it is preferable to use a nonaqueous organic solvent containing one or more cyclic carbonates with high dielectric constants and one or more chain carbonates or chain esters other than chain carbonates with low liquid viscosity, since this increases the ionic conductivity of the electrolyte solution. Specifically, it is more preferable to use a nonaqueous organic solvent containing the following combinations:

[0027] (1) Combination of EC and EMC, (2) Combination of EC and DEC, (3) Combination of EC, DMC and EMC, (4) Combination of EC, DEC and EMC, (5) Combination of EC, EMC and EP, (6) Combination of PC and DEC, (7) Combination of PC and EMC, (8) Combination of PC and EP, (9) Combination of PC, DMC and EMC, (10) Combination of PC, DEC and EMC, (11) Combination of PC, DEC and EP, (12) Combination of PC, EC and EMC, (13) Combination of PC, EC, DMC and EMC, (14) Combination of PC, EC, DEC and EMC, (15) Combination of PC, EC, EMC and EP

[0028] Other additives The above This disclosure This is a description of the basic configuration of the nonaqueous electrolyte solution of the present disclosure, but additives that are generally used in the nonaqueous electrolyte solution of the present disclosure may be added in any ratio as long as the gist of the present disclosure is not impaired.

[0029] Specific examples include vinylene carbonate (hereinafter sometimes referred to as "VC"), vinylene carbonate oligomer (number average molecular weight in polystyrene equivalent: 170 to 5000), vinyl ethylene carbonate, fluoroethylene carbonate (hereinafter sometimes referred to as "FEC"), 1,6-diisocyanatohexane, ethynyl ethylene carbonate, trans-difluoroethylene carbonate, propane sultone, propene sultone, 1,3,2-dioxathiolane-2,2-dioxide, 4-propyl-1,3,2-dioxathiolane-2,2-dioxide, methylenemethane disulfonate, 1,2-ethanediol, Examples of compounds that have an overcharge prevention effect, a negative electrode coating effect, or a positive electrode protection effect include sulfonic acid anhydride, methanesulfonyl fluoride, tris(trimethylsilyl)borate, (ethoxy)pentafluorocyclotriphosphazene, lithium tetrafluoro(malonato)phosphate, tetrafluoro(picolinato)phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,3-hexafluoroisopropyl)disiloxane, t-butylbenzene, t-amylbenzene, fluorobenzene, cyclohexylbenzene, biphenyl, difluoroanisole, and dimethylvinylene carbonate.

[0030] Also, carboxylic acid salts such as lithium acrylate, sodium acrylate, lithium methacrylate, and sodium methacrylate, lithium methyl sulfate, sodium methyl sulfate, lithium ethyl sulfate, and sodium workman Sulfuric acid ester salts such as methyl sulfate may also be added.

[0031] Furthermore, as in the case of non-aqueous electrolyte secondary batteries known as lithium polymer batteries, the non-aqueous electrolyte may be quasi-solidified with a gelling agent or crosslinked polymer and used.

[0032] The nonaqueous electrolyte solution of the present disclosure may contain a compound represented by any one of the following general formulas [1] to [5], difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, fluorosulfonate, or the like.

[0033] TIFF0007719394000001.tif29169

[0034] [In general formula [1], R a and R b each independently represent a fluorine atom, an alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkenyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom, an alkynyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom, an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom, an alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkenyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom, an alkynyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom, or an aryloxy group having 6 to 10 carbon atoms which may be substituted with a halogen atom, A represents a hydrogen atom or a halogen atom.

[0035] In addition, This disclosure In the formula, "may be substituted with a halogen atom" means that R a or R b This means that at least one hydrogen atom of the alkyl group or the like may be substituted with a halogen atom.

[0036] R in the above general formula [1] a and R b Examples of the alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a trifluoromethyl group, and a trifluoroethyl group, etc. Among these, a methyl group is preferred.

[0037] R in the above general formula [1] a and R b Examples of the alkenyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom include a vinyl group, an allyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, an isobutenyl group, and a 1,1-difluoro-1-propenyl group, etc. Among these, an allyl group which may be substituted with a halogen atom is preferred.

[0038] R in the above general formula [1] a and R b Examples of the alkynyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom include a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, and a 3-butynyl group, etc. Among these, a 2-propynyl group which may be substituted with a halogen atom is preferred.

[0039] R in the above general formula [1] a and R b Examples of the aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom include a phenyl group, a tosyl group, a xylyl group, a naphthyl group, a trifluorophenyl group, and a pentafluorophenyl group.

[0040] R in the above general formula [1] a and R b Examples of the alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a trifluoromethoxy group, and a trifluoroethoxy group, etc. Among these, an alkoxy group having 1 to 3 carbon atoms is preferred, and a methoxy group is particularly preferred.

[0041] R in the above general formula [1] a and R bExamples of the alkenyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom include an allyloxy group, a 1-methyl-2-propenyloxy group, a 2-methyl-2-propenyloxy group, a 2-butenyloxy group, a 3-butenyloxy group, and a propenyloxy group, etc. Among these, an alkenyloxy group having 2 to 4 carbon atoms or an allyloxy group is preferred.

[0042] R in the above general formula [1] a and R b Examples of the alkynyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom include a 2-propynyloxy group, a 1-methyl-2-propynyloxy group, a 2-methyl-2-propynyloxy group, a 2-butynyloxy group, and a 3-butynyloxy group, etc. Among these, an alkynyloxy group having 2 to 4 carbon atoms or a 2-propynyloxy group is preferred.

[0043] R in the above general formula [1] a and R b Examples of the aryloxy group having 6 to 10 carbon atoms which may be substituted with a halogen atom include a phenoxy group, a 2-methylphenoxy group, a 3-methylphenoxy group, a 4-methylphenoxy group, a 2-ethylphenoxy group, a 3-ethylphenoxy group, a 4-ethylphenoxy group, a 2-methoxyphenoxy group, a 3-methoxyphenoxy group, and a 4-methoxyphenoxy group, etc. Among these, a phenoxy group which may be substituted with a halogen atom is preferred.

[0044] R in the above general formula [1] a and R b As the "halogen atom" in the above, a fluorine atom is preferred from the viewpoint of battery resistance.

[0045] Furthermore, examples of the "halogen atom" represented by A in the general formula [1] include a fluorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom is preferred from the viewpoint of lowering the battery resistance.

[0046] Examples of the compound represented by the general formula [1] include 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide, 3-dimethylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-diethylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-diphenylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-bis-allylphosphinyl Oxytetrahydrothiophene-1,1-dioxide, 3-divinylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-dipropargylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-dimethoxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-diethoxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-diphenoxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethoxyphosphin phosphinyloxytetrahydrothiophene-1,1-dioxide, 3-bis-allyloxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-bis-cyclohexyloxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-dimethylphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-diethylphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethylphosphinyloxy-4-fluorotetrahydrothiophene tetrahydrothiophene-1,1-dioxide, 3-diphenylphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-diallylphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-divinylphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-dipropargylphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-dimethoxyphosphinyloxy-4-fluorotetrahydrothiophene-1,Examples of suitable tetrahydrothiophene-1,1-dioxide include 3-diethoxyphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-diphenoxyphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethoxy-4-fluorophosphinyloxytetrahydrothiophene-1,1-dioxide, 3-bis-allyloxy-4-fluorophosphinyloxytetrahydrothiophene-1,1-dioxide, and 3-bis-cyclohexyloxyphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide. Among these, from the viewpoint of further suppressing the initial resistance, it is preferable to contain at least one compound selected from the group consisting of 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide, 3-dimethylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-diphenylphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-dimethoxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-bis-allyloxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-diphenoxyphosphinyloxytetrahydrothiophene-1,1-dioxide, 3-dimethoxyphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-bis-allyloxy-4-fluorophosphinyloxytetrahydrothiophene-1,1-dioxide, and 3-dipropargylphosphinyloxytetrahydrothiophene-1,1-dioxide.

[0047] TIFF0007719394000002.tif24169

[0048] [In general formula [2], R 1 and R 2are each independently an organic group selected from a fluorine atom, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms, a linear alkoxy group having 1 to 10 carbon atoms or a branched alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may also contain a fluorine atom, an oxygen atom, or an unsaturated bond. 1 and R 2 At least one of the groups is a fluorine atom. M m+ is an alkali metal cation, alkaline earth metal cation, or onium cation, m represents an integer equal to the valence of the corresponding cation.

[0049] In addition, This disclosure In the above, "a fluorine atom is present in the organic group" means that at least one hydrogen atom of the organic group is substituted with a fluorine atom. The phrase "an oxygen atom is present in an organic group" means that an oxygen atom is contained between at least one carbon-carbon bond of the organic group. The phrase "an unsaturated bond is present in an organic group" means that at least one carbon-carbon bond in the organic group is an unsaturated bond.

[0050] In the above general formula [2], R 1 or R 2Examples of the linear alkyl group having 1 to 10 carbon atoms or the branched alkyl group having 3 to 10 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a trifluoromethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyl group. Of these, a methyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, and a 1,1,2,2,2-pentafluoroethyl group are preferred.

[0051] Examples of the linear alkoxy group having 1 to 10 carbon atoms or the branched alkoxy group having 3 to 10 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, a 2,2-difluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropyloxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group. Of these, a methoxy group, a 2,2-difluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropyloxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group are preferred.

[0052] Examples of the alkenyl group having 2 to 10 carbon atoms include a vinyl group, an allyl group, a 1-propenyl group, an isopropenyl group, a 2-butenyl group, and a 1,3-butadienyl group, etc. Of these, a vinyl group is preferred.

[0053] Examples of the alkenyloxy group having 2 to 10 carbon atoms include a vinyloxy group, an allyloxy group, a 1-propenyloxy group, an isopropenyloxy group, a 2-butenyloxy group, and a 1,3-butadienyloxy group, etc. Of these, an allyloxy group is preferred.

[0054] Examples of the alkynyl group having 2 to 10 carbon atoms include an ethynyl group, a 2-propynyl group, and a 1,1-dimethyl-2-propynyl group.

[0055] Examples of the alkynyloxy group having 2 to 10 carbon atoms include an ethynyloxy group, a 2-propynyloxy group, and a 1,1-dimethyl-2-propynyloxy group, etc. Of these, the 2-propynyloxy group is preferred.

[0056] Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group and a cyclohexyl group.

[0057] Examples of the cycloalkoxy group having 3 to 10 carbon atoms include a cyclopentyloxy group and a cyclohexyloxy group.

[0058] Examples of the cycloalkenyl group having 3 to 10 carbon atoms include a cyclopentenyl group and a cyclohexenyl group.

[0059] Examples of the cycloalkenyloxy group having 3 to 10 carbon atoms include a cyclopentenyloxy group and a cyclohexenyloxy group.

[0060] Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a 2-fluorophenyl group, a pentafluorophenyl group, a tolyl group, and a xylyl group. Of these, a phenyl group, a 2-fluorophenyl group, and a pentafluorophenyl group are preferred.

[0061] Examples of the aryloxy group having 6 to 10 carbon atoms include a phenyloxy group, a 2-fluorophenyloxy group, a pentafluorophenyloxy group, a tolyloxy group, and a xylyloxy group. Of these, the phenyloxy group is preferred.

[0062] More specifically, examples of the anion of the compound represented by the general formula [2] include the following compounds No. 2-1 to No. 2-17, etc., where: This disclosureThe compound represented by the general formula [2] used in the above is not limited to the following examples.

[0063] TIFF0007719394000003.tif170169

[0064] In the above general formula [2], for example, R 1 is a fluorine atom, and R 2 When is a group other than a fluorine atom, the group other than a fluorine atom is preferably a group selected from hydrocarbon groups having 6 or less carbon atoms which may contain a fluorine atom. is These groups are preferred because they tend to result in a relatively small internal resistance when a coating is formed on an electrode, and in particular, methyl groups, ethyl groups, n-propyl groups, vinyl groups, allyl groups, ethynyl groups, 2-propynyl groups, phenyl groups, trifluoromethyl groups, 2,2-difluoroethyl groups, 2,2,2-trifluoroethyl groups, 2,2,3,3-tetrafluoropropyl groups, 1,1,1,3,3,3-hexafluoroisopropyl groups, and alkoxy groups, alkenyloxy groups, and alkynyloxy groups derived from these groups are preferred because they result in a nonaqueous electrolyte secondary battery that can exhibit a good balance between cycle characteristics and internal resistance characteristics.

[0065] As the anion of the compound represented by the general formula [2], among the compounds No. 2-1 to No. 2-17, compounds No. 2-1, No. 2-2, No. 2-3, No. 2-6, No. 2-10, No. 2-11, No. 2-14, and No. 2-16 are more preferable from the viewpoint of suppressing an increase in internal resistance, and compounds No. 2-1, No. 2-2, No. 2-6, and No. 2-10 are particularly preferable.

[0066] TIFF0007719394000004.tif23169

[0067] [In general formula [3], R 3 ~R 6are each independently an organic group selected from a fluorine atom, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms, a linear alkoxy group having 1 to 10 carbon atoms or a branched alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may also contain a fluorine atom, an oxygen atom, a cyano group, or an unsaturated bond. 3 ~R 6 At least one of the groups is a fluorine atom. Also, M m+ , m is the same as in general formula [2].

[0068] In addition, This disclosure In the above, "a cyano group is present in the organic group" means that at least one hydrogen atom of the organic group is substituted with a cyano group.

[0069] In the above general formula [3], R 3 ~R 6 Examples of the linear alkyl group having 1 to 10 carbon atoms or the branched alkyl group having 3 to 10 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyl group.

[0070] Examples of the linear alkoxy group having 1 to 10 carbon atoms or the branched alkoxy group having 3 to 10 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, a 2,2-difluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropyloxy group, a 1,1,1,3,3,3-hexafluoroisopropoxy group, and a 2-cyanoethoxy group. Of these, a methoxy group, a 2,2-difluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 1,1,1,3,3,3-hexafluoroisopropoxy group, and a 2-cyanoethoxy group are preferred.

[0071] Examples of the alkenyl group having 2 to 10 carbon atoms include a vinyl group, an allyl group, a 1-propenyl group, an isopropenyl group, a 2-butenyl group, and a 1,3-butadienyl group.

[0072] Examples of the alkenyloxy group having 2 to 10 carbon atoms include a vinyloxy group, an allyloxy group, a 1-propenyloxy group, an isopropenyloxy group, a 2-butenyloxy group, and a 1,3-butadienyloxy group, etc. Of these, an allyloxy group is preferred.

[0073] Examples of the alkynyl group having 2 to 10 carbon atoms include an ethynyl group, a 2-propynyl group, and a 1,1-dimethyl-2-propynyl group.

[0074] Examples of the alkynyloxy group having 2 to 10 carbon atoms include an ethynyloxy group, a 2-propynyloxy group, and a 1,1-dimethyl-2-propynyloxy group, etc. Of these, the 2-propynyloxy group is preferred.

[0075] Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group and a cyclohexyl group.

[0076] Examples of the cycloalkoxy group having 3 to 10 carbon atoms include a cyclopentyloxy group and a cyclohexyloxy group.

[0077] Examples of the cycloalkenyl group having 3 to 10 carbon atoms include a cyclopentenyl group and a cyclohexenyl group.

[0078] Examples of the cycloalkenyloxy group having 3 to 10 carbon atoms include a cyclopentenyloxy group and a cyclohexenyloxy group.

[0079] Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a 2-fluorophenyl group, a pentafluorophenyl group, a tolyl group, and a xylyl group.

[0080] Examples of the aryloxy group having 6 to 10 carbon atoms include a phenyloxy group, a 2-fluorophenyloxy group, a pentafluorophenyloxy group, a tolyloxy group, and a xylyloxy group. Of these, the phenyloxy group is preferred.

[0081] More specifically, examples of the anion of the compound represented by the general formula [3] include the following compounds No. 3-1 to No. 3-13, etc., where: This disclosure The compound represented by the general formula [3] used in the above is not limited to the following examples: In the formula, Me represents a methyl group.

[0082] TIFF0007719394000005.tif210163

[0083] In the above general formula [3], R 3 ~R 6 At least one of R is a fluorine atom, 3 ~R 6 At least one of the above is preferably a group selected from hydrocarbon groups having 6 or less carbon atoms which may contain a fluorine atom. isis preferred because the internal resistance when a coating is formed on an electrode tends to be relatively small, and in particular, at least one group selected from a methyl group, an ethyl group, an n-propyl group, a vinyl group, an allyl group, an ethynyl group, a 2-propynyl group, a phenyl group, a trifluoromethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and an alkoxy group, an alkenyloxy group, or an alkynyloxy group derived from any of these groups is preferred because a nonaqueous electrolyte secondary battery that can exhibit a good balance between cycle characteristics and internal resistance characteristics can be obtained.

[0084] As the anion of the compound represented by the general formula [3], among the compounds No. 3-1 to No. 3-13, compounds No. 3-1, No. 3-2, No. 3-3, No. 3-4, No. 3-6, No. 3-7, No. 3-9, and No. 3-13 are more preferable from the viewpoint of suppressing an increase in internal resistance, and compounds No. 3-1, No. 3-2, No. 3-4, and No. 3-9 are particularly preferable.

[0085] TIFF0007719394000006.tif23169

[0086] [In general formula [4], R 7 ~R 9 are each independently an organic group selected from a fluorine atom, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms, a linear alkoxy group having 1 to 10 carbon atoms or a branched alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may also contain a fluorine atom, an oxygen atom, or an unsaturated bond. 7 ~R 9At least one of the groups is a fluorine atom. Also, M m+ , m is the same as in general formula [2].

[0087] In the above general formula [4], R 7 ~R 9 Examples of the linear alkyl group having 1 to 10 carbon atoms or the branched alkyl group having 3 to 10 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a trifluoromethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyl group. Of these, a methyl group and a trifluoromethyl group are preferred.

[0088] Examples of the linear alkoxy group having 1 to 10 carbon atoms or the branched alkoxy group having 3 to 10 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, a 2,2-difluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropyloxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group. Of these, a methoxy group, an ethoxy group, a 2,2,2-trifluoroethoxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group are preferred.

[0089] Examples of the alkenyl group having 2 to 10 carbon atoms include a vinyl group, an allyl group, a 1-propenyl group, an isopropenyl group, a 2-butenyl group, and a 1,3-butadienyl group, etc. Of these, a vinyl group is preferred.

[0090] Examples of the alkenyloxy group having 2 to 10 carbon atoms include a vinyloxy group, an allyloxy group, a 1-propenyloxy group, an isopropenyloxy group, a 2-butenyloxy group, and a 1,3-butadienyloxy group, etc. Of these, an allyloxy group is preferred.

[0091] Examples of the alkynyl group having 2 to 10 carbon atoms include an ethynyl group, a 2-propynyl group, and a 1,1-dimethyl-2-propynyl group.

[0092] Examples of the alkynyloxy group having 2 to 10 carbon atoms include an ethynyloxy group, a 2-propynyloxy group, and a 1,1-dimethyl-2-propynyloxy group, etc. Of these, the 2-propynyloxy group is preferred.

[0093] Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group and a cyclohexyl group.

[0094] Examples of the cycloalkoxy group having 3 to 10 carbon atoms include a cyclopentyloxy group and a cyclohexyloxy group.

[0095] Examples of the cycloalkenyl group having 3 to 10 carbon atoms include a cyclopentenyl group and a cyclohexenyl group.

[0096] Examples of the cycloalkenyloxy group having 3 to 10 carbon atoms include a cyclopentenyloxy group and a cyclohexenyloxy group.

[0097] Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a 2-fluorophenyl group, a pentafluorophenyl group, a tolyl group, and a xylyl group.

[0098] Examples of the aryloxy group having 6 to 10 carbon atoms include a phenyloxy group, a 2-fluorophenyloxy group, a pentafluorophenyloxy group, a tolyloxy group, and a xylyloxy group. Of these, a phenyloxy group and a tolyloxy group are preferred.

[0099] More specifically, examples of the anion of the compound represented by the general formula [4] include the following compounds No. 4-1 to No. 4-18, etc., where: This disclosureThe compound represented by the general formula [4] used in the above is not limited to the following examples: In the formula, Me represents a methyl group, and Et represents an ethyl group.

[0100] TIFF0007719394000007.tif222169

[0101] In the above general formula [4], R 7 ~R 9 At least one of R is a fluorine atom, 7 ~R 9 At least one of the above is preferably a group selected from hydrocarbon groups having 6 or less carbon atoms which may contain a fluorine atom. is is preferred because the internal resistance when a coating is formed on an electrode tends to be relatively small, and in particular, at least one group selected from a methyl group, an ethyl group, an n-propyl group, a vinyl group, an allyl group, an ethynyl group, a 2-propynyl group, a phenyl group, a trifluoromethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and an alkoxy group, an alkenyloxy group, or an alkynyloxy group derived from any of these groups is preferred because a nonaqueous electrolyte secondary battery that can exhibit a good balance between cycle characteristics and internal resistance characteristics can be obtained.

[0102] As the anion of the compound represented by the general formula [4], among the compounds No. 4-1 to No. 4-18, compounds No. 4-1, No. 4-2, No. 4-3, No. 4-5, No. 4-6, No. 4-7, No. 4-10, No. 4-11, No. 4-15, No. 4-17, and No. 4-18 are more preferable from the viewpoint of suppressing an increase in internal resistance, and compounds No. 4-1, No. 4-2, No. 4-5, No. 4-6, No. 4-7, No. 4-15, and No. 4-18 are particularly preferable.

[0103] In the general formulas [2] to [4], M m+is preferably selected from the group consisting of lithium ions, sodium ions, potassium ions, and tetraalkylammonium ions, more preferably lithium ions or sodium ions, and particularly preferably lithium ions.

[0104] TIFF0007719394000008.tif9169

[0105] [In general formula [5], R 10 are each independently a group having a carbon-carbon unsaturated bond, and R 11 are each independently a fluorine atom, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms which may be substituted with a fluorine atom, and a linear alkoxy group having 1 to 10 carbon atoms or a branched alkoxy group having 3 to 10 carbon atoms which may be substituted with a fluorine atom. a is an integer from 2 to 4.

[0106] In the above general formula [5], R 10 Examples of groups having a carbon-carbon unsaturated bond represented by the formula (I) include alkenyl groups having 2 to 8 carbon atoms, such as vinyl, allyl, 1-propenyl, 2-propenyl, isopropenyl, 2-butenyl, and 1,3-butadienyl, or alkenyloxy groups derived from these groups; alkynyl groups having 2 to 8 carbon atoms, such as ethynyl, 2-propynyl, and 1,1-dimethyl-2-propynyl, or alkynyloxy groups derived from these groups; and aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, and xylyl, or aryloxy groups derived from these groups. The above groups may also contain fluorine and oxygen atoms. "Containing a fluorine atom" means that a hydrogen atom bonded to a carbon atom has been replaced with a fluorine atom, and "containing an oxygen atom" means that an oxygen atom is present between the carbon-carbon bond as an ether bond. Among these, groups containing a carbon-carbon unsaturated bond having 6 or less carbon atoms are preferred. isThese groups are preferred because they tend to result in a relatively small internal resistance when a coating is formed on an electrode. Specifically, groups selected from the group consisting of vinyl groups, allyl groups, 1-propenyl groups, 2-propenyl groups, ethynyl groups, and 2-propynyl groups are preferred, with vinyl groups being particularly preferred.

[0107] In addition, in the above general formula [5], R 11 Examples of the alkyl group represented by the formula (I) include alkyl groups having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, and a pentyl group. The above groups may also contain a fluorine atom and an oxygen atom. Examples of groups containing an oxygen atom include alkoxy groups derived from the above alkyl groups. Groups selected from alkyl groups and alkoxy groups tend to have lower resistance when a coating is formed on an electrode, and as a result are preferred from the standpoint of output characteristics. In particular, groups selected from the group consisting of methyl, ethyl, n-propyl, 2,2,2-trifluoroethyl, 2,2,3,3-tetrafluoropropyl, 1,1,1-trifluoroisopropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,2-trifluoroethoxy, 2,2,3,3-tetrafluoropropoxy, 2,2,3,3,3-pentafluoropropoxy, 1,1,1-trifluoroisopropoxy, and 1,1,1,3,3,3-hexafluoroisopropoxy are preferred, since they can provide a nonaqueous electrolyte battery with superior high-temperature cycle characteristics and high-temperature storage characteristics without increasing the internal resistance when a coating is formed on an electrode.

[0108] The number of groups having a carbon-carbon unsaturated bond represented by a in the above general formula [5] is preferably an integer of 2 to 4 in order to form a film on the electrode, and is preferably 3 or 4 because it is easier to improve the high-temperature cycle characteristics and high-temperature storage characteristics, and is particularly preferably 4. Although the details are unknown, it is thought that this is because it is easier to form a stronger film.

[0109] More specifically, examples of the compound represented by the general formula [5] include the following compounds Nos. 5-1 to 5-20. This disclosure The silane compounds used in the above step 1 are not limited to the following examples.

[0110] TIFF0007719394000009.tif145169

[0111] As the compound represented by the general formula [5], among the compounds No. 5-1 to No. 5-20, compounds No. 5-1, No. 5-2, No. 5-3, No. 5-4, No. 5-5, No. 5-6, No. 5-8, No. 5-9, No. 5-12, No. 5-17, No. 5-18, and No. 5-20 are more preferred from the viewpoint of improving durability at high temperatures, and compounds No. 5-2, No. 5-4, No. 5-5, No. 5-8, and No. 5-18 are particularly preferred.

[0112] The nonaqueous electrolyte solution of the present disclosure may be prepared from a difluoro(oxalato)borate, a bis(oxalato)borate, a tetrafluoro(oxalato)phosphate, a difluorobis(oxalato)phosphate, a tris(oxalato)phosphate, a difluorophosphate, a fluorosulfonate, a bis(fluorosulfonyl)imide salt, vinylene carbonate, a vinylene carbonate oligomer (having a number average molecular weight of 170 to 5000 in terms of polystyrene), vinylethylene carbonate, fluoroethylene carbonate, 1,6-diisocyanatohexane, ethynylethylene carbonate, trans-difluoroethylene carbonate, propane sultone, propene sultone, 1,3,2-dioxathiolane-2,2 -dioxide, 4-propyl-1,3,2-dioxathiolane-2,2-dioxide, methylenemethane disulfonate, 1,2-ethanedisulfonic anhydride, methanesulfonyl fluoride, tris(trimethylsilyl)borate, (ethoxy)pentafluorocyclotriphosphazene, lithium tetrafluoro(malonato)phosphate, tetrafluoro(picolinato)phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,3-hexafluoroisopropyl)disiloxane, t-butylbenzene, t-amylbenzene, fluorobenzene, and cyclohexylbenzene.

[0113] When the nonaqueous electrolyte solution according to this embodiment contains the other additives, the content thereof is preferably 0.01 mass % or more and 5.00 mass % or less with respect to the total amount of the electrolyte solution.

[0114] The nonaqueous electrolyte solution of the present disclosure described above is suitably used in nonaqueous electrolyte secondary batteries, and is particularly preferably used in nonaqueous electrolyte secondary batteries equipped with a current collector containing copper. The nonaqueous electrolyte solution of the present disclosure can suppress an increase in initial resistance when used in a nonaqueous electrolyte secondary battery. When used in a nonaqueous electrolyte secondary battery including a current collector containing copper, the nonaqueous electrolyte solution also exhibits the effect of reducing elution of the copper component, which is the metal of the current collector, into the electrolyte.

[0115] 2. Non-aqueous electrolyte secondary batteries Next, the configuration of the nonaqueous electrolyte secondary battery of the present disclosure will be described. The nonaqueous electrolyte secondary battery of the present disclosure is characterized by using the nonaqueous electrolyte of the present disclosure described above, and other components are the same as those used in general nonaqueous electrolyte secondary batteries.

[0116] The nonaqueous electrolyte secondary battery may be a nonaqueous electrolyte secondary battery including (a) the nonaqueous electrolyte, (b) a positive electrode, (c) a negative electrode, and (d) a separator, as described below.

[0117] [(A) Positive electrode] (a) The positive electrode preferably contains at least one type of oxide and / or polyanion compound as a positive electrode active material.

[0118] [Cathode active material] In the case of a lithium ion secondary battery in which the cations in the nonaqueous electrolyte solution are mainly lithium, (i) the positive electrode active material constituting the positive electrode is not particularly limited as long as it is a material that can be charged and discharged. Examples include materials containing at least one of (A) lithium transition metal composite oxides containing at least one metal selected from nickel, manganese, and cobalt and having a layered structure, (B) lithium manganese composite oxides having a spinel structure, (C) lithium-containing olivine-type phosphates, and (D) lithium-excess layered transition metal oxides having a layered rock salt structure.

[0119] ((A) Lithium transition metal composite oxide) Positive electrode active material (A) lithium transition metal composite oxides containing at least one metal selected from nickel, manganese, and cobalt and having a layered structure include, for example, lithium-cobalt composite oxide, lithium-nickel composite oxide, lithium-nickel-cobalt composite oxide, lithium-nickel-cobalt-aluminum composite oxide, lithium-cobalt-manganese composite oxide, lithium-nickel-manganese composite oxide, lithium-nickel-manganese-cobalt composite oxide, etc. Furthermore, some of the transition metal atoms that make up the main components of these lithium transition metal composite oxides may be substituted with other elements such as Al, Ti, V, Cr, Fe, Cu, Zn, Mg, Ga, Zr, Si, B, Ba, Y, and Sn.

[0120] Specific examples of lithium-cobalt composite oxides and lithium-nickel composite oxides include LiCoO2, LiNiO2, and lithium cobalt oxide (LiCoO) containing different elements such as Mg, Zr, Al, and Ti. 0.98 Mg 0.01 Zr 0.01 O2, LiCo 0.98 Mg 0.01 Al 0.01 O2, LiCo 0.975 Mg 0.01 Zr 0.005 Al 0.01 Lithium cobalt oxide having a rare earth compound fixed to the surface, as described in WO2014 / 034043, may also be used. Also, as described in JP2002-151077A, LiCoO2 particles having a part of their particle surfaces coated with aluminum oxide may also be used.

[0121] Lithium-nickel-cobalt composite oxide and lithium-nickel-cobalt-aluminum composite oxide are represented by the general formula (6). Li a Ni 1-b-c Co b M 1 c O2(6) In formula (6), M 1is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, and B, a is 0.9≦a≦1.2, and b and c satisfy the conditions of 0.01≦b≦0.3 and 0≦c≦0.1. These can be prepared, for example, according to the manufacturing method described in JP-A-2009-137834. 0.8 Co 0.2 O2, LiNi 0.85 Co 0.10 Al 0.05 O2, LiNi 0.87 Co 0.10 Al 0.03 O2, LiNi 0.90 Co 0.07 Al 0.03 O2, LiNi 0.6 Co 0.3 Al 0.1 Examples include O2.

[0122] Specific examples of lithium-cobalt-manganese composite oxide and lithium-nickel-manganese composite oxide are LiNi 0.5 Mn 0.5 O2, LiCo 0.5 Mn 0.5 Examples include O2.

[0123] The lithium-nickel-manganese-cobalt composite oxide includes the lithium-containing composite oxide represented by the general formula (7). Li d Ni e Mn f Co g M 2 h O2(7) In formula (7), M 2 is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, B, and Sn, d is 0.9≦d≦1.2, and e, f, g, and h satisfy the conditions e+f+g+h=1, 0≦e≦0.9, 0≦f≦0.5, 0≦g≦0.5, and h≧0.

[0124] The lithium-nickel-manganese-cobalt composite oxide preferably contains manganese in the range shown in general formula (7) to enhance structural stability and improve safety at high temperatures in lithium secondary batteries, and more preferably further contains cobalt in the range shown in general formula (7) to enhance the high-rate characteristics of lithium-ion secondary batteries. Specifically, for example, Li[Ni 1 / 3 Mn 1 / 3 Co 1 / 3 ]O2, Li[Ni 0.45 Mn 0.35 Co 0.2 ]O2, Li[Ni 0.5 Mn 0.3 Co 0.2 ]O2, Li[Ni 0.6 Mn 0.2 Co 0.2 ]O2, Li[Ni 0.8 Mn 0.1 Co 0.1 ]O2, Li[Ni 0.49 Mn 0.3 Co 0.2 Zr 0.01 ]O2, Li[Ni 0.49 Mn 0.3 Co 0.2 Mg 0.01 ]O2, Li[Ni 0.8 Mn 0.1 Co 0.1 ]O2, etc.

[0125] ((B) Lithium manganese composite oxide with spinel structure) An example of the lithium manganese composite oxide having a spinel structure as the positive electrode active material (B) is a spinel-type lithium manganese composite oxide represented by the general formula (8). Li j (Mn 2-k M 3 k )O4(8) In formula (8), M 3 is at least one metal element selected from the group consisting of Ni, Co, Fe, Mg, Cr, Cu, Al, and Ti, j is 1.05≦j≦1.15, and k is 0≦k≦0.20. Specifically, for example, LiMn2O4, LiMn 1.95 Al 0.05 O4, LiMn 1.9 Al 0.1 O4, LiMn 1.9 Ni 0.1 O4, LiMn 1.5 Ni 0.5 O4 and the like can be mentioned.

[0126] ((C) Lithium-containing olivine-type phosphate) Examples of the positive electrode active material (C) lithium-containing olivine-type phosphate include those represented by the general formula (9). LiFe 1-n M 4 n PO4(9) In the formula (9), M 4 is at least one selected from Co, Ni, Mn, Cu, Zn, Nb, Mg, Al, Ti, W, Zr, and Cd, and n is 0 ≦ n ≦ 1. Specifically, for example, LiFePO4, LiCoPO4, LiNiPO4, LiMnPO4, etc. can be mentioned, and among them, LiFePO4 and / or LiMnPO4 are preferable.

[0127] ((D) Lithium-excess layered transition metal oxide) Examples of the positive electrode active material (D) lithium-excess layered transition metal oxide having a layered rock salt structure include those represented by the general formula (10). xLiM 5 O2·(1 - x)Li2M 6 O3(10) In the formula (10), x is a number satisfying 0 < x < 1, and M 5 is at least one or more metal elements having an average oxidation number of 3 + and M 6 is at least one metal element having an average oxidation number of 4 + . In the formula (10), M 5 is preferably one metal element selected from trivalent Mn, Ni, Co, Fe, V, Cr, but it may also have an average oxidation number of 3 with equal amounts of divalent and tetravalent metals. In addition, in formula (10), M 6 is preferably one or more metal elements selected from Mn, Zr, and Ti. 0.5 Mn 0.5 O2]·0.5[Li2MnO3], 0.5[LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2]·0.5[Li2MnO3], 0.5[LiNi 0.375 Co 0.25 Mn 0.375 O2]·0.5[Li2MnO3], 0.5[LiNi 0.375 Co 0.125 Fe 0.125 Mn 0.375 O2]·0.5[Li2MnO3], 0.45[LiNi 0.375 Co 0.25 Mn 0.375 O2]·0.10[Li2TiO3]·0.45[Li2MnO3], etc. The positive electrode active material (D) represented by the general formula (10) is known to exhibit high capacity when charged at a high voltage of 4.4 V (based on Li) or higher (for example, US Pat. No. 7,135,252). These positive electrode active materials can be prepared in accordance with the manufacturing methods described in, for example, JP-A No. 2008-270201, WO2013 / 118661, JP-A No. 2013-030284, and the like. The positive electrode active material may contain at least one selected from the above (A) to (D) as a main component, but other components that may be contained include, for example, transition element chalcogenides such as FeS2, TiS2, V2O5, MoO3, and MoS2; conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole; activated carbon; radical-generating polymers; and carbon materials.

[0128] [Positive electrode current collector] (a) The positive electrode has a positive electrode current collector, which may be made of, for example, aluminum, stainless steel, nickel, titanium, or an alloy thereof.

[0129] [Cathode active material layer] (A) The positive electrode has, for example, a positive electrode active material layer formed on at least one surface of a positive electrode current collector. The positive electrode active material layer is composed of, for example, the above-mentioned positive electrode active material, a binder, and, if necessary, a conductive agent.

[0130] Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, and styrene butadiene rubber (SBR) resin.

[0131] As the conductive agent, for example, carbon materials such as acetylene black, ketjen black, carbon fiber, or graphite (granular graphite or flake graphite) can be used. For the positive electrode, it is preferable to use acetylene black or ketjen black, which have low crystallinity.

[0132] [(c) Negative electrode] (c) The negative electrode preferably contains at least one negative electrode active material.

[0133] [Negative electrode active material] In the case of a lithium-ion secondary battery in which the cations in the nonaqueous electrolyte are primarily lithium, (c) the negative electrode active material constituting the negative electrode is capable of doping and dedoping lithium ions. Examples include (E) carbon materials with a d value of the lattice plane (002 plane) of 0.340 nm or less in X-ray diffraction, (F) carbon materials with a d value of the lattice plane (002 plane) of greater than 0.340 nm in X-ray diffraction, (G) oxides of one or more metals selected from Si, Sn, and Al, (H) alloys containing one or more metals selected from Si, Sn, and Al, or alloys of these metals or alloys with lithium, and (I) lithium titanium oxide. These negative electrode active materials can be used alone or in combination. Lithium metal, metal nitrides, tin compounds, conductive polymers, etc. may also be used.

[0134] ((E) Carbon material with a d value of the lattice plane (002 plane) of 0.340 nm or less in X-ray diffraction) Examples of carbon materials having a d value of 0.340 nm or less in the lattice plane (002 plane) in X-ray diffraction for the negative electrode active material (E) include pyrolytic carbons, cokes (e.g., pitch coke, needle coke, petroleum coke, etc.), graphites, fired organic polymer compounds (e.g., phenolic resins, furan resins, etc., fired at an appropriate temperature and carbonized), carbon fibers, activated carbons, etc., which may be graphitized. The carbon materials have a lattice spacing (d002) of 0.340 nm or less in the (002) plane measured by X-ray diffraction, and among these, those having a true density of 1.70 g / cm 3 Graphite or a highly crystalline carbon material having properties similar to those of graphite is preferred.

[0135] ((F) Carbon materials with d values of lattice planes (002 planes) exceeding 0.340 nm in X-ray diffraction) Carbon materials with a d value of the lattice plane (002 plane) exceeding 0.340 nm in X-ray diffraction of the negative electrode active material (F) include amorphous carbon, which is a carbon material whose stacking order remains almost unchanged even when heat-treated at high temperatures of 2000°C or higher. Examples include non-graphitizable carbon (hard carbon), mesocarbon microbeads (MCMB) fired at 1500°C or lower, and mesophase pitch carbon fiber (MCF). Carbotron (registered trademark) P manufactured by Kureha Corporation is a representative example.

[0136] ((G) Oxides of one or more metals selected from Si, Sn, and Al) The negative electrode active material (G) is an oxide of one or more metals selected from Si, Sn, and Al, and examples thereof include silicon oxide and tin oxide, which can be doped and dedoped with lithium ions. SiO2 with a structure in which ultrafine Si particles are dispersed in SiO2 x When this material is used as the negative electrode active material, the Si reacting with Li is in the form of ultrafine particles, so charging and discharging can be performed smoothly, while the SiO x Since the particles themselves have a small surface area, the particles have good paint properties when made into a composition (paste) for forming a negative electrode active material layer, and the negative electrode mixture layer has good adhesion to the current collector. In addition, SiO x Since the volume change during charging and discharging is large, SiO x and the graphite of the negative electrode active material (E) in a specific ratio in the negative electrode active material, it is possible to achieve both high capacity and good charge-discharge cycle characteristics.

[0137] ((H) One or more metals selected from Si, Sn, and Al, or alloys containing these metals, or alloys of these metals or alloys with lithium) Examples of the negative electrode active material (H) include one or more metals selected from Si, Sn, and Al, alloys containing these metals, and alloys of these metals or alloys with lithium. Examples include metals such as silicon, tin, and aluminum, silicon alloys, tin alloys, and aluminum alloys. Materials in which these metals or alloys are alloyed with lithium during charge and discharge can also be used. Preferred examples of these include metals such as silicon (Si) and tin (Sn) (e.g., powders), alloys of these metals, compounds containing these metals, and alloys of these metals containing tin (Sn) and cobalt (Co), as described in WO 2004 / 100293 and JP 2008-016424 A. These metals are preferred because, when used in electrodes, they can achieve high charge capacities and exhibit relatively little volume expansion or contraction during charge and discharge. Furthermore, these metals are known to achieve high charge capacities when used in the negative electrodes of lithium-ion secondary batteries because they form alloys with Li during charging, which also makes them preferred in this respect. Furthermore, negative electrode active materials formed from silicon pillars with submicron diameters, negative electrode active materials made of silicon fibers, and the like, as described in publications such as WO2004 / 042851 and WO2007 / 083155, may also be used.

[0138] ((I) Lithium Titanium Oxide) Examples of the negative electrode active material (I), lithium titanium oxide, include lithium titanate having a spinel structure and lithium titanate having a ramsdellite structure. Examples of lithium titanate having a spinel structure include Li4+α Ti5O 12 (α varies within the range of 0≦α≦3 depending on the charge / discharge reaction). Examples of lithium titanate having a ramsdellite structure include Li 2+β An example is Ti3O7 (β varies within the range of 0≦β≦3 depending on the charge / discharge reaction). These negative electrode active materials can be prepared in accordance with the manufacturing methods described in, for example, JP-A Nos. 2007-018883 and 2009-176752.

[0139] On the other hand, in the case of a sodium ion secondary battery in which the cations in the non-aqueous electrolyte are mainly sodium, for example, hard carbon or oxides such as TiO2, V2O5, MoO3, etc. are used as the negative electrode active material. For example, in the case of a sodium ion secondary battery in which the cations in the non-aqueous electrolyte are mainly sodium, for example, sodium-containing transition metal composite oxides such as NaFeO2, NaCrO2, NaNiO2, NaMnO2, NaCoO2, etc., and mixtures of multiple transition metals such as Fe, Cr, Ni, Ti, Mn, Co, etc. in these sodium-containing transition metal composite oxides (for example, NaNi 0.5 Ti 0.3 Mn 0.2 O2), sodium-containing transition metal composite oxides in which part of the transition metal has been replaced with a metal other than the transition metal, transition metal phosphate compounds such as Na2FeP2O7 and NaCo3(PO4)2P2O7, sulfides such as TiS2 and FeS2, conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole, activated carbon, radical-generating polymers, carbon materials, etc., are used.

[0140] [Negative electrode current collector] (c) The negative electrode has a negative electrode current collector. As the negative electrode current collector, for example, copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof can be used. The nonaqueous electrolyte secondary battery of the present disclosure preferably contains copper as the negative electrode current collector. When the nonaqueous electrolyte of the present disclosure is used in a nonaqueous electrolyte secondary battery containing copper as the negative electrode current collector, an effect of suppressing copper elution into the electrolyte can be obtained in addition to an effect of suppressing an increase in initial resistance.

[0141] [Negative electrode active material layer] (c) The negative electrode has, for example, a negative electrode active material layer formed on at least one surface of a negative electrode current collector. The negative electrode active material layer is composed of, for example, the above-mentioned negative electrode active material, a binder, and, if necessary, a conductive agent.

[0142] Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, and styrene butadiene rubber (SBR) resin.

[0143] As the conductive agent, for example, carbon materials such as acetylene black, ketjen black, carbon fiber, or graphite (granular graphite or flake graphite) can be used.

[0144] [Method for manufacturing electrodes ((a) positive electrode and (c) negative electrode)] The electrode can be obtained, for example, by dispersing and kneading the active material, binder, and optionally conductive agent in predetermined amounts in a solvent such as N-methyl-2-pyrrolidone (NMP) or water, applying the resulting paste to a current collector, and drying to form an active material layer. The resulting electrode is preferably compressed by a method such as a roll press to adjust the electrode to an appropriate density.

[0145] [(D) Separator] The nonaqueous electrolyte secondary battery includes a separator (d). The separator prevents contact between the positive electrode (b) and the negative electrode (c). A nonwoven fabric or porous sheet made of polyolefins such as polypropylene or polyethylene, cellulose, paper, or glass fiber is used as the separator. These films are preferably microporous so that the electrolyte can penetrate and ions can easily pass through.

[0146] Examples of polyolefin separators include microporous polymer films such as porous polyolefin films, which electrically insulate the positive and negative electrodes and are permeable to lithium ions. Specific examples of porous polyolefin films include porous polyethylene films alone, or multilayer films formed by stacking porous polyethylene films and porous polypropylene films. Other examples include composite films of porous polyethylene films and polypropylene films.

[0147] [Exterior body] In constructing a nonaqueous electrolyte secondary battery, the exterior body of the nonaqueous electrolyte secondary battery can be, for example, a coin-shaped, cylindrical, or rectangular metal can or a laminate exterior body. Examples of metal can materials include nickel-plated steel plate, stainless steel plate, nickel-plated stainless steel plate, aluminum or its alloy, nickel, and titanium.

[0148] Examples of the laminate exterior body that can be used include aluminum laminate film, SUS laminate film, silica-coated polypropylene, polyethylene, and the like laminate film.

[0149] The configuration of the nonaqueous electrolyte secondary battery according to this embodiment is not particularly limited, but may be, for example, a configuration in which an electrode element in which a positive electrode and a negative electrode are arranged opposite each other, and a nonaqueous electrolyte are enclosed in an exterior body. The shape of the nonaqueous electrolyte secondary battery is not particularly limited, but an electrochemical device in a shape such as a coin, a cylinder, a square, or an aluminum laminate sheet is assembled from the above components. [Example]

[0150] The present disclosure will be further specifically explained below using examples, but the scope of the present disclosure is not limited to these examples in any way.

[0151] <Preparation of Electrolyte No. 1-1 to 1-8 and Comparative Electrolyte No. 1-1 to 1-3> As a non-aqueous solvent, a mixed solvent obtained by mixing ethylene carbonate (hereinafter referred to as "EC"), propylene carbonate (hereinafter referred to as "PC"), dimethyl carbonate (hereinafter referred to as "DMC"), and ethyl methyl carbonate (hereinafter referred to as "EMC") at a volume ratio of EC:PC:DMC:EMC = 2:1:3:4 was used. Lithium hexafluorophosphate (hereinafter referred to as "LiPF6") was dissolved in the solvent as a solute to a concentration of 1.00 mol / L, and further LiN(SO2F)(COCN) was dissolved as (I) to a concentration of 0.02% by mass to prepare Electrolyte No. 1-1. The above preparation was carried out while maintaining the liquid temperature at 25°C. The preparation conditions of Electrolyte No. 1-1 are shown in Table 1. Also, by changing the type and concentration of (I) as shown in Table 1 below, Electrolyte No. 1-2 to 1-8 and Comparative Electrolyte No. 1-1 to 1-3 were prepared in the same procedure as the preparation of Electrolyte No. 1-1 except for this. In the preparation of Comparative Electrolyte No. 1-2 and 1-3, succinonitrile (hereinafter referred to as "SN") was used instead of (I).

[0152]

Table 1

[0153] <Preparation of NCM811 Positive Electrode> LiNi 0.8 Co 0.1 Mn 0.1 To 91.0% by mass of LiNi 0.8 Co 0.1 Mn[[ID=二十九]] 0.1 45% by mass of O2 powder, polyvinylidene fluoride (hereinafter referred to as "PVDF") as a binder, and 4.5% by mass of acetylene black as a conductive material were mixed. Further, N-methyl-2-pyrrolidone (hereinafter referred to as "NMP") was added to the total mass of LiNi

[0154] <Preparation of graphite negative electrode> A negative electrode composite paste was prepared by mixing 98.0% by mass of artificial graphite powder with 1.0% by mass of carboxymethyl cellulose (hereinafter "CMC") and 1.0% by mass of styrene-butadiene copolymer (hereinafter "SBR") as binders, and then adding 50% by mass of pure water based on the total mass of the artificial graphite powder and binder. This paste was applied to one side of copper foil, dried, pressed, and then punched out to a 4.5 cm x 5.5 cm piece to obtain a graphite negative electrode for testing.

[0155] [Examples 1-1 to 1-8, Comparative Examples 1-1 to 1-3] <Fabrication of non-aqueous electrolyte secondary battery> Aluminum laminate exterior cells (capacity 70 mAh) equipped with the above-mentioned test NCM811 positive electrode, test graphite negative electrode, and cellulose separator were impregnated with electrolyte solutions Nos. 1-1 to 1-8 and comparative electrolyte solutions Nos. 1-1 to 1-3 listed in Table 1 above, respectively, to obtain nonaqueous electrolyte secondary batteries according to Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-3.

[0156] 〔evaluation〕 The nonaqueous electrolyte secondary batteries according to Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-3 were each evaluated as follows.

[0157] <Low temperature output characteristics (initial resistance evaluation)> Each cell impregnated with the electrolyte solution as described above was left to stand for 12 hours at an ambient temperature of 25° C. (impregnation time: 12 hours), and then conditioned under the following conditions at an ambient temperature of 25° C. That is, as the initial charge / discharge cycle, the cells were charged at a constant current / constant voltage of 0.1 C rate (7 mA) with an upper charge voltage of 4.3 V, and discharged at a constant current / constant voltage of 0.2 C rate to a discharge cut-off voltage of 3.0 V. Thereafter, the cells were charged at a constant current / constant voltage of 0.2 C rate with an upper charge voltage of 4.3 V, and discharged at a constant current / constant voltage of 0.2 C rate to a discharge cut-off voltage of 3.0 V, and this charge / discharge cycle was repeated three times. After the above conditioning, the battery was charged at a constant current / constant voltage rate of 0.2 C at an ambient temperature of 25°C up to an upper charge voltage of 4.3 V, and then discharged at a constant current rate of 5 C at an ambient temperature of -30°C down to a discharge cut-off voltage of 3.0 V, and the discharge capacity (-30°C discharge capacity) was measured. Table 2 below lists the relative capacity values of each Example and Comparative Example, with the capacity of Comparative Example 1-1 set to 100. A larger relative capacity value indicates a smaller initial resistance.

[0158] In addition to evaluating the initial resistance, the initial discharge capacity and overdischarge characteristics were also evaluated as indicators of the effect of suppressing the elution of copper, which is the negative electrode current collector, into the electrolyte.

[0159] <Comparison of initial discharge capacity> Each cell impregnated with the electrolyte solution as described above was left to stand for 3 days at an ambient temperature of 25°C (impregnation time: 3 days), and then, as an initial charge / discharge, it was charged at a constant current / constant voltage of 0.1C rate (7mA) to an upper charge voltage limit of 4.3V at an ambient temperature of 25°C, and discharged at a constant current / constant voltage of 0.2C rate to a discharge cut-off voltage of 3.0V, and the initial discharge capacities were compared. Table 2 shows the relative values of the initial discharge capacities of each Example and Comparative Example, with the capacity of Comparative Example 1-1 set to 100.

[0160] <Overdischarge characteristics> Each cell impregnated with the electrolyte solution as described above was left to stand at an ambient temperature of 25°C for 12 hours (impregnation time: 12 hours), and then conditioned at an ambient temperature of 25°C under the following conditions: First, the cells were charged at a constant current and constant voltage at a 0.1C rate (7mA) with a maximum charging voltage of 4.3V, and then discharged at a constant current and constant voltage of 0.2C to a discharge cut-off voltage of 3.0V. This charge-discharge cycle was repeated three times, followed by three cycles of constant current and constant voltage charging at a 0.2C rate with a maximum charging voltage of 4.3V, and then discharged at a constant current and constant voltage of 0.2C to a discharge cut-off voltage of 3.0V. The discharge capacity of this third cycle was designated the initial capacity. After the conditioning, the discharged cell was further discharged to 0 V at a constant resistance of 75 Ω to create an overdischarge state, and then left for 3 days. After leaving, the cell was again charged at a constant current and voltage of 0.2 C at an ambient temperature of 25°C with an upper charge voltage limit of 4.3 V, and then discharged at a constant current and voltage of 0.2 C to a discharge cut-off voltage of 3.0 V. The discharge capacity at this time was measured, and the capacity retention rate relative to the initial capacity was calculated. Table 2 below lists the "discharge capacity retention rate after overdischarge," which is the relative value of the capacity retention rate of each Example and Comparative Example, with the capacity retention rate of Comparative Example 1-1 set to 100.

[0161] [Table 2]

[0162] Comparing the above results, when comparing the discharge capacities at low temperatures, Comparative Examples 1-2 and 1-3, in which succinonitrile was added, showed lower discharge capacities than Comparative Example 1-1, but the various electrolyte solutions to which (I) was added showed significantly increased discharge capacities, confirming that the increase in initial resistance was suppressed.

[0163] Furthermore, when comparing the initial discharge capacities, it was found that by using (I), even when the impregnation time was long, the initial discharge capacity was equivalent to that of Comparative Examples 1-2 and 1-3, suggesting that the elution of copper, which is the negative electrode current collector, was suppressed. Furthermore, when comparing the discharge capacity retention rate after overdischarge, it was found that by using (I), even in the case of an overdischarge state, the discharge capacity retention rate after overdischarge was equivalent to that of Comparative Example 1-2, suggesting that the elution of copper, which is the negative electrode current collector, was suppressed. When the active material contains carbon, the potential of the negative electrode before charging is equal to or greater than the copper dissolution potential, and copper dissolution begins as soon as the electrolyte is poured in. It is generally known that the cell capacity decreases when the dissolved copper deposits on the positive electrode or on the negative electrode during charging.

Claims

1. (I) a compound represented by the following general formula [1a], (II) a solute; and (III) a nonaqueous organic solvent; and the concentration of (II) is 0.5 mol / L or more and 2.5 mol / L or less. M + [X-S(=O) 2 -N-C(=O)-R] - [1a] (In the general formula [1a], X represents a halogen atom, R represents a —CN group or an —OCN group, and M + represents an alkali metal ion.

2. The nonaqueous electrolyte solution according to claim 1, wherein X in the general formula [1a] is a fluorine atom.

3. A non-aqueous electrolyte solution as described in claim 1 or 2, wherein (I) is at least one selected from the group consisting of LiN(SO2F)(COCN), LiN(SO2F)(CO(OCN)), NaN(SO2F)(COCN), NaN(SO2F)(CO(OCN)), LiN(SO2Cl)(COCN), LiN(SO2Cl)(CO(OCN)), NaN(SO2Cl)(COCN), and NaN(SO2Cl)(CO(OCN)).

4. A non-aqueous electrolyte solution as described in claim 1 or 2, wherein (I) is at least one selected from the group consisting of LiN(SO2F)(COCN), LiN(SO2F)(CO(OCN)), NaN(SO2F)(COCN), and NaN(SO2F)(CO(OCN)).

5. The nonaqueous electrolyte solution according to any one of claims 1 to 4, wherein the concentration of (I) is 0.01 to 5.00 mass% with respect to the total amount of the electrolyte solution.

6. The non-aqueous electrolyte solution according to claim 1, wherein the concentration of (I) is 0.1 to 2.0 mass % relative to the total amount of the electrolyte solution.

7. The (II) is LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiAlO 2 , LiAlCl 4 , LiCl, and LiI, or NaPF 6 , NaBF 4 , NaSbF 6 , NaAsF 6 , NaClO 4 , NaCF 3 SO 3 , NaC 4 F 9 SO 3 , NaAlO 2 , NaAlCl 4 7. The non-aqueous electrolyte solution according to claim 1, wherein the non-aqueous electrolyte solution is at least one selected from the group consisting of NaCl, NaI, and NaI.

8. The non-aqueous electrolyte solution according to claim 1, wherein (II) contains at least LiPF 6 or at least NaPF 6 .

9. A non-aqueous electrolyte solution described in any one of claims 1 to 8, wherein (II) is LiPF6 and at least one selected from the group consisting of LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiC4F9SO3, LiAlO2, LiAlCl4, LiCl, and LiI, or NaPF6 and at least one selected from the group consisting of NaBF4, NaSbF6, NaAsF6, NaClO4, NaCF3SO3, NaC4F9SO3, NaAlO2, NaAlCl4, NaCl, and NaI.

10. The nonaqueous electrolyte solution according to claim 1, wherein the (II) is LiPF 6 .

11. The nonaqueous electrolyte solution according to any one of claims 1 to 10, wherein the (III) is at least one selected from the group consisting of a cyclic ester, a chain ester, a cyclic ether, a chain ether, a sulfone compound, a sulfoxide compound, and an ionic liquid.

12. The nonaqueous electrolyte solution according to claim 11 , wherein the compound (III) is a cyclic ester, and the cyclic ester is a cyclic carbonate.

13. The nonaqueous electrolyte solution according to claim 11 , wherein the (III) is a chain ester, and the chain ester is a chain carbonate.

14. The nonaqueous electrolyte solution according to claim 1, wherein (III) comprises at least one selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, methyl propionate, and ethyl propionate.

15. The (III) is (1) a combination of ethylene carbonate and ethyl methyl carbonate, (2) a combination of ethylene carbonate and diethyl carbonate, (3) a combination of ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, (4) a combination of ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, (5) a combination of ethylene carbonate, ethyl methyl carbonate and ethyl propionate, (6) a combination of propylene carbonate and diethyl carbonate, (7) a combination of propylene carbonate and ethyl methyl carbonate, (8) a combination of propylene carbonate and ethyl propionate, (9) a combination of propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, (1 (10) A combination of propylene carbonate, diethyl carbonate, and ethyl methyl carbonate, (11) A combination of propylene carbonate, diethyl carbonate, and ethyl propionate, (12) A combination of propylene carbonate, ethylene carbonate, and ethyl methyl carbonate, (13) A combination of propylene carbonate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, (14) A combination of propylene carbonate, ethylene carbonate, diethyl carbonate, and ethyl methyl carbonate, and (15) A combination of propylene carbonate, ethylene carbonate, ethyl methyl carbonate, and ethyl propionate. The nonaqueous electrolyte solution according to any one of claims 1 to 10 and 14, 16. The nonaqueous electrolyte solution according to any one of claims 1 to 10, 14 and 15, wherein (III) comprises a combination of propylene carbonate, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate.

17. Further, difluoro(oxalato)borates, bis(oxalato)borates, tetrafluoro(oxalato)phosphates, difluorobis(oxalato)phosphates, tris(oxalato)phosphates, difluorophosphates, fluorosulfonates, bis(fluorosulfonyl)imide salts, vinylene carbonate, vinylene carbonate oligomers (having a number average molecular weight of 170 to 5000 in terms of polystyrene), vinylethylene carbonate, fluoroethylene carbonate, 1,6-diisocyanatohexane, ethynylethylene carbonate, trans-difluoroethylene carbonate, propane sultone, propene sultone, 1,3,2-dioxathiolane-2,2-dioxide, 4-propyl 17. The non-aqueous electrolyte solution according to any one of claims 1 to 16, comprising at least one additive selected from the group consisting of 1,3,2-dioxathiolane-2,2-dioxide, methylenemethane disulfonate, 1,2-ethanedisulfonic anhydride, methanesulfonyl fluoride, tris(trimethylsilyl)borate, (ethoxy)pentafluorocyclotriphosphazene, lithium tetrafluoro(malonato)phosphate, tetrafluoro(picolinato)phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,3-hexafluoroisopropyl)disiloxane, t-butylbenzene, t-amylbenzene, fluorobenzene, and cyclohexylbenzene.

18. The nonaqueous electrolyte solution according to any one of claims 1 to 17, further comprising a compound represented by any one of the following general formulas [1] to [5]: [In general formula [1], R a and R b each independently represent a fluorine atom, an alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkenyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom, an alkynyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom, an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom, an alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkenyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom, an alkynyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom, or an aryloxy group having 6 to 10 carbon atoms which may be substituted with a halogen atom; A represents a hydrogen atom or a halogen atom. [In general formula [2], R 1 and R 2 each independently represent an organic group selected from a fluorine atom, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may contain a fluorine atom, an oxygen atom, or an unsaturated bond, provided that at least one of R 1 and R 2 is a fluorine atom. M m+ is an alkali metal cation, an alkaline earth metal cation, or an onium cation; m represents an integer equal to the valence of the corresponding cation. [In general formula [3], R3 to R6 are each independently an organic group selected from a fluorine atom, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may contain a fluorine atom, an oxygen atom, a cyano group, or an unsaturated bond, provided that at least one of R3 to R6 is a fluorine atom. Furthermore, M m+ and m are the same as in general formula [2]. [In general formula [4], R 7 to R 9 are each independently an organic group selected from a fluorine atom, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms, a linear alkoxy group having 1 to 10 carbon atoms or a branched alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may contain a fluorine atom, an oxygen atom, or an unsaturated bond, provided that at least one of R 7 to R 9 is a fluorine atom. Furthermore, M m+ and m are the same as in general formula [2]. [In general formula [5], Each R 10 is independently a group having a carbon-carbon unsaturated bond, and each R 11 is independently a fluorine atom, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms which may be substituted with a fluorine atom, or a linear alkoxy group having 1 to 10 carbon atoms or a branched alkoxy group having 3 to 10 carbon atoms which may be substituted with a fluorine atom. a is an integer of 2 to 4.

19. The non-aqueous electrolyte solution according to any one of claims 1 to 18, which is used in a non-aqueous electrolyte secondary battery having a current collector containing copper.

20. A non-aqueous electrolyte secondary battery comprising at least a positive electrode, a negative electrode, a separator, and the non-aqueous electrolyte solution according to any one of claims 1 to 19.

21. 21. The nonaqueous electrolyte secondary battery according to claim 20, wherein the negative electrode contains copper as a current collector.

22. The nonaqueous electrolyte secondary battery according to claim 20, wherein the negative electrode contains at least one negative electrode active material selected from the group consisting of: (E) a carbon material having a d value of the lattice plane (002 plane) of 0.340 nm or less in X-ray diffraction; (F) a carbon material having a d value of the lattice plane (002 plane) of more than 0.340 nm in X-ray diffraction; (G) an oxide of one or more metals selected from Si, Sn, and Al; (H) one or more metals selected from Si, Sn, and Al or alloys containing these metals, or alloys of these metals or alloys with lithium; and (I) lithium titanium oxide.

23. The nonaqueous electrolyte secondary battery according to claim 22, wherein the negative electrode active material is at least one selected from the group consisting of (E) carbon materials having a d value of the lattice plane (002 plane) of 0.340 nm or less in X-ray diffraction, and (F) carbon materials having a d value of the lattice plane (002 plane) of more than 0.340 nm in X-ray diffraction.

24. A non-aqueous electrolyte secondary battery as described in claim 22 or 23, wherein the negative electrode active material is artificial graphite.

25. The nonaqueous electrolyte secondary battery according to claim 20, wherein the positive electrode contains at least one positive electrode active material selected from the group consisting of (A) a lithium transition metal composite oxide containing at least one metal selected from the group consisting of nickel, manganese, and cobalt, and having a layered structure, (B) a lithium manganese composite oxide having a spinel structure, (C) a lithium-containing olivine-type phosphate, and (D) a lithium-excess layered transition metal oxide having a layered rock salt-type structure.

26. The nonaqueous electrolyte secondary battery according to claim 25, wherein the positive electrode active material is a lithium-containing composite oxide represented by general formula (7): Li d Ni e Mn f Co g M 2 h O 2 (7) In formula (7), M2 is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, B, and Sn, d is 0.9≦d≦1.2, and e, f, g, and h satisfy the conditions e+f+g+h=1, 0≦e≦0.9, 0≦f≦0.5, 0≦g≦0.5, and h≧0.

27. The non-aqueous electrolyte secondary battery according to claim 25 or 26, wherein the positive electrode active material is LiNi 0.8 Co 0.1 Mn 0.1 O 2 .

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