Nonaqueous electrolyte and nonaqueous electrolyte secondary battery

Abstract

Provided are: a nonaqueous electrolyte that makes it possible to further improve low-temperature characteristics and high-temperature storage characteristics; and a nonaqueous electrolyte secondary battery that comprises the nonaqueous electrolyte.　A nonaqueous electrolyte that includes (I) a first additive that is represented by general formula [1], (II) at least one type of second additive that is selected from the group that consists of compounds that are represented by general formulas [2]–[5], difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluoro bis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate, (III) a nonaqueous organic solvent, and (IV) a solute.

Description

[Technical field]

[0001] The present invention relates to a nonaqueous electrolyte and a nonaqueous electrolyte secondary battery comprising the nonaqueous electrolyte. [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 of improving 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 electrolyte to suppress degradation due to electrolyte decomposition on the surface of the active positive and negative electrodes.

[0003] For example, Patent Document 1 discloses that, when used in an electricity storage device such as a non-aqueous electrolyte secondary battery, in order to improve battery characteristics in terms of long-term cycle characteristics, resistance characteristics, and initial resistance characteristics, a compound in which a cyclic sulfone group is bonded to a phosphinyloxy group is included as an additive in the electrolyte. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 016195 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0005] The electrolyte described in Patent Document 1, when used in an electricity storage device such as a nonaqueous electrolyte secondary battery, exhibits an effect of improving battery characteristics in terms of cycle characteristics, resistance characteristics, and initial resistance characteristics at 25°C. However, there has been a demand for further improvement in long-term high-temperature storage characteristics and low-temperature characteristics in a wide temperature environment of -40°C to +80°C, as required for automotive batteries and large stationary batteries.

[0006] Therefore, an object of the present invention is to provide a nonaqueous electrolyte solution that can further improve high-temperature storage characteristics and low-temperature characteristics, and a nonaqueous electrolyte secondary battery including the nonaqueous electrolyte solution. [Means for solving the problem]

[0007] In view of these problems, the present inventors conducted extensive research and found that by adding a first additive, which is a compound in which a cyclic sulfone group is bonded to a phosphinyloxy group, and a specified second additive to a nonaqueous electrolyte solution containing a nonaqueous organic solvent and a solute, when the electrolyte solution is used in a nonaqueous electrolyte secondary battery, the high-temperature storage characteristics and low-temperature characteristics can be further improved, thereby completing the present invention.

[0008] That is, the present invention provides (I) a first additive represented by the following general formula [1]: (II) at least one second additive selected from the group consisting of compounds represented by the following general formulas [2] to [5], difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate; (III) a nonaqueous organic solvent, and (IV) solute; The present invention relates to a non-aqueous electrolyte solution comprising:

[0009] [ka] [In formula [1], R a and R beach 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.

[0010] [ka] [In formula [2], R 1 and R 2 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, in which a fluorine atom, an oxygen atom, or an unsaturated bond may be present in the organic group, with the proviso that R 1 and R 2 At least one of is a fluorine atom, M m+ is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and m represents an integer equal to the valence of the corresponding cation.

[0011] [ka] [In formula [3], R 3 ~R 6 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, in which a fluorine atom, an oxygen atom, a cyano group, or an unsaturated bond may be present in the organic group, with the proviso that R 3 ~R 6 at least one of is a fluorine atom, and M m+ and m are the same as in general formula [2].

[0012] [ka] [In formula [4], R 7 ~R 9are 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, in which a fluorine atom, an oxygen atom, or an unsaturated bond may be present in the organic group, with the proviso that R 7 ~R 9 at least one of is a fluorine atom, and M m+ and m are the same as in general formula [2].

[0013] [ka] [In formula [5], R 10 each independently represents a group having a carbon-carbon unsaturated bond, R 11 each independently represents 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, and a is an integer from 2 to 4.

[0014] Although the mechanism by which the present invention improves the battery characteristics is not clear, it is important to use the first additive and the second additive in combination. It is presumed that by adding them in combination, the decomposition products of the first additive and the second additive combine to form an SEI, and the composite coating, which has excellent permeability to cations such as lithium ions and sodium ions, further improves high-temperature storage characteristics and low-temperature characteristics.

[0015] In the above general formula [1], R a and R b are preferably each independently a fluorine atom, an alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom, an alkenyloxy group having 2 to 4 carbon atoms which may be substituted with a halogen atom, an alkynyloxy group having 2 to 4 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.

[0016] In the above general formula [1], A is preferably a hydrogen atom or a fluorine atom.

[0017] In the above general formula [2], when the compound has an SF bond, excellent low-temperature properties can be obtained. The more the number of SF bonds, the more the low-temperature properties can be improved, which is preferable. 1 and R 2 It is particularly preferable that each of them is a fluorine atom.

[0018] In addition, in the above general formula [2], R 1 is a fluorine atom, R 2 is preferably an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, or an alkynyloxy group having 6 or less carbon atoms which may contain a fluorine atom.

[0019] In addition, in the above general formula [2], R 1 is a fluorine atom, R 2is preferably a group selected from a methyl group, a methoxy group, an ethyl group, an ethoxy group, an n-propyl group, an n-propoxy group, an isopropyl group, an isopropoxy group, a vinyl group, an allyl group, an allyloxy group, an ethynyl group, a 2-propynyl group, a 2-propynyloxy group, a phenyl group, a phenyloxy group, a trifluoromethyl group, a trifluoromethoxy group, a 2,2-difluoroethyl group, a 2,2-difluoroethyloxy group, a 2,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyloxy group, a 2,2,3,3-tetrafluoropropyl group, a 2,2,3,3-tetrafluoropropyloxy group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyloxy group.

[0020] In the above general formula [3], when the compound has a PF bond, excellent low-temperature properties can be obtained. The more the number of PF bonds, the more the low-temperature properties can be improved, which is preferable. 3 ~R 6 It is particularly preferable that each of the groups is a fluorine atom.

[0021] In addition, in the above general formula [3], R 3 ~R 6 At least one of the following is a fluorine atom: R 3 ~R 6 At least one of these is preferably a group selected from alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkenyloxy groups, and alkynyloxy groups having 6 or less carbon atoms, which may contain a fluorine atom.

[0022] In addition, in the above general formula [3], R 3 ~R 6 At least one of the following is a fluorine atom: R 3 ~R 6At least one of these is preferably a group selected from a methyl group, a methoxy group, an ethyl group, an ethoxy group, an n-propyl group, an n-propoxy group, an isopropyl group, an isopropoxy group, a vinyl group, an allyl group, an allyloxy group, an ethynyl group, a 2-propynyl group, a 2-propynyloxy group, a phenyl group, a phenyloxy group, a trifluoromethyl group, a trifluoromethoxy group, a 2,2-difluoroethyl group, a 2,2-difluoroethyloxy group, a 2,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyloxy group, a 2,2,3,3-tetrafluoropropyl group, a 2,2,3,3-tetrafluoropropyloxy group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyloxy group.

[0023] In the above general formula [4], when a PF bond or an SF bond is present, excellent low-temperature properties can be obtained. The more the number of the PF bonds or the SF bonds, the further the low-temperature properties can be improved, which is preferable. 7 ~R 9 It is particularly preferable that each of the groups is a fluorine atom.

[0024] In addition, in the above general formula [4], R 7 ~R 9 At least one of the groups is a fluorine atom, R 7 ~R 9 At least one of these is preferably a group selected from alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkenyloxy groups, and alkynyloxy groups having 6 or less carbon atoms, which may contain a fluorine atom.

[0025] In addition, in the above general formula [4], R 7 ~R 9 At least one of the following is a fluorine atom: R 7 ~R 9At least one of these is preferably a group selected from a methyl group, a methoxy group, an ethyl group, an ethoxy group, an n-propyl group, an n-propoxy group, an isopropyl group, an isopropoxy group, a vinyl group, an allyl group, an allyloxy group, an ethynyl group, a 2-propynyl group, a 2-propynyloxy group, a phenyl group, a phenyloxy group, a trifluoromethyl group, a trifluoromethoxy group, a 2,2-difluoroethyl group, a 2,2-difluoroethyloxy group, a 2,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyloxy group, a 2,2,3,3-tetrafluoropropyl group, a 2,2,3,3-tetrafluoropropyloxy group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyloxy group.

[0026] In addition, in the above general formulas [2] to [4], M m+ is preferably selected from the group consisting of lithium ions, sodium ions, potassium ions, and tetraalkylammonium ions. In the above general formula [5], R 10 are each preferably independently a group selected from the group consisting of a vinyl group, an allyl group, a 1-propenyl group, a 2-propenyl group, an ethynyl group, and a 2-propynyl group.

[0027] In addition, in the above general formula [5], R 11 are each independently a group selected from the group consisting of a fluorine atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a 2,2,2-trifluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,1-trifluoroisopropyl group, a 1,1,1,3,3,3-hexafluoroisopropyl group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropoxy group, a 2,2,3,3,3-pentafluoropropoxy group, a 1,1,1-trifluoroisopropoxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group.

[0028] In the above general formula [5], it is more preferable that a is 3 or 4, and it is particularly preferable that a is 4.

[0029] In addition, the counter cation of the above difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate is preferably a group selected from the group consisting of a lithium ion, a sodium ion, a potassium ion, and a tetraalkylammonium ion.

[0030] The content of the above (I) relative to the total amount of the above (I) to (IV) is preferably 0.01 to 10.0 mass %, more preferably 0.05 to 5.0 mass %, and particularly preferably 0.5 to 2.0 mass %.

[0031] The content of the above (II) relative to the total amount of the above (I) to (IV) is preferably 0.005 to 12.0 mass %, more preferably 0.05 to 10.0 mass %, and particularly preferably 0.1 to 5.0 mass %.

[0032] The above (IV) 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, LiI, NaPF 6 , NaBF 4 , NaSbF 6 , NaAsF 6 , NaClO 4 , NaCF 3 SO 3 , NaC 4 F 9 SO 3, NaAlO 2 , NaAlCl 4 , NaCl, and NaI.

[0033] The above (III) is preferably at least one selected from the group consisting of cyclic carbonates, chain carbonates, cyclic esters, chain esters, cyclic ethers, chain ethers, sulfone compounds, sulfoxide compounds, and ionic liquids. It is more preferable that the above (III) contains a cyclic carbonate, and in particular, it is preferable that the above (III) contains at least one selected from the group consisting of ethylene carbonate, propylene carbonate, fluoroethylene carbonate, vinylene carbonate, and vinylethylene carbonate.

[0034] The non-aqueous electrolyte solution may further contain vinylene carbonate, vinylene carbonate oligomer (having a number average molecular weight of 170 to 5000 in terms of polystyrene), vinyl ethylene carbonate, fluoroethylene carbonate, 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, methylene methane disulfonate, 1,2-ethane disulfonate, and at least one additive selected from the group consisting of sulfonic anhydride, methanesulfonyl fluoride, tris(trimethylsilyl)borate, succinonitrile, (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.

[0035] The present invention also provides a nonaqueous electrolyte secondary battery comprising at least a positive electrode, a negative electrode, and the above-mentioned nonaqueous electrolyte. Effect of the Invention

[0036] According to the present invention, it is possible to provide a nonaqueous electrolyte solution capable of further improving high-temperature storage characteristics and low-temperature characteristics, and a nonaqueous electrolyte secondary battery including the nonaqueous electrolyte solution. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The present invention will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present invention, and the present invention is not limited to these specific contents. Various modifications can be made within the scope of the gist of the present invention.

[0038] 1. Non-aqueous electrolyte The nonaqueous electrolyte solution of the present invention contains (I) a first additive represented by the above general formula [1], (II) at least one second additive selected from the group consisting of the compounds represented by the above general formulas [2] to [5], difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate, (III) a nonaqueous organic solvent, and (IV) a solute.

[0039] (I) First Additive The compound represented by the above general formula [1] is considered 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 presumably intended to prevent the decomposition of the nonaqueous organic solvent or the solute by suppressing direct contact between the active material and the nonaqueous organic solvent or the solute, thereby suppressing the deterioration of the battery performance.

[0040] In the present invention, the term "optionally 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 represented by the formula (I) may be substituted with a halogen atom.

[0041] R in the above general formula [1] a and R bExamples 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 preferable.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] R in the above general formula [1] a and R bExamples 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.

[0046] R in the above general formula [1] a and R b Examples 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 or an allyloxy group having 2 to 4 carbon atoms is preferred.

[0047] 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.

[0048] 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.

[0049] R in the above general formula [1]a and R b From the viewpoint of battery resistance, the "halogen atom" is preferably a fluorine atom.

[0050] 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.

[0051] The compound represented by the above general formula [1] can be obtained by using available raw materials and combining ordinary reactions. For example, R in the above general formula [1] a and R b In the case where each of the groups is a methyl group and A is a hydrogen atom, 3-dimethylphosphinyloxytetrahydrothiophene-1,1-dioxide can be obtained by reacting 3-hydroxysulfolane with dimethylphosphinic chloride as described in the examples of Patent Document 1. Specifically, 3-dimethylphosphinyloxytetrahydrothiophene-1,1-dioxide can be produced as follows. Pyridine is placed in a flask, and 3-hydroxysulfolane is added in an ice bath. Dimethylphosphinyl chloride is then added dropwise in an ice bath, and the temperature is raised to 60°C. The reaction solution is stirred for 12 hours while maintaining the temperature. Water is then added, and the precipitate is filtered and washed by repulping with methyl tert-butyl ether (MTBE). The resulting crystals are dried to produce 3-dimethylphosphinyloxytetrahydrothiophene-1,1-dioxide.

[0052] Examples of the compound represented by the above 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-trifluoromethoxyphosphine 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-1,1-dioxide, lahydrothiophene-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-1,1-dioxide, 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.

[0053] The preferred content of (I) relative to the total amount of (I) to (IV) is 0.01% by mass at the lower limit and 10.0% by mass at the upper limit. If the content is 0.01% by mass or more, the effect of suppressing deterioration of battery performance is easily exhibited, and if the content is 10.0% by mass or less, a decrease in the charge / discharge efficiency of the battery due to excessive film formation is unlikely to occur. The content is more preferably 0.05 to 5.0% by mass, and particularly preferably 0.5 to 2.0% by mass.

[0054] (II) Second Additive It is believed that the second additive partially decomposes at the interface between the positive electrode and the electrolyte and at the interface between the negative electrode and the electrolyte to form a relatively thin coating. It is presumed that the combined use of the first additive and the second additive forms the composite coating having excellent cation permeability such as lithium ions and sodium ions, resulting in improved high-temperature storage characteristics and low-temperature characteristics.

[0055] [Regarding the compound represented by the general formula [2]] In the above general formula [2], R 1 and R 2 It is important that at least one of the above is a fluorine atom. Although the reason is not clear, when at least one of the above is a fluorine atom, the effect of suppressing the internal resistance of a battery using the electrolyte is large.

[0056] R 1 and R 2 In the organic group represented by the formula (I), a fluorine atom, an oxygen atom or an unsaturated bond may be present.

[0057] In the present invention, "a fluorine atom is present in an organic group" means that at least one hydrogen atom in 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 that the organic group has. 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.

[0058] 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 (1) 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. Among these, a methyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, and a 1,1,2,2,2-pentafluoroethyl group are preferred.

[0059] 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-tetrafluoropropoxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group. Among these, a methoxy group, a 2,2-difluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropoxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group are preferred.

[0060] 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. Among these, the vinyl group is preferable.

[0061] 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. Among these, an allyloxy group is preferable.

[0062] 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.

[0063] 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. Of these, the 2-propynyloxy group is preferred.

[0064] Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group and a cyclohexyl group.

[0065] Examples of the cycloalkoxy group having 3 to 10 carbon atoms include a cyclopentyloxy group and a cyclohexyloxy group.

[0066] Examples of the cycloalkenyl group having 3 to 10 carbon atoms include a cyclopentenyl group and a cyclohexenyl group.

[0067] Examples of the cycloalkenyloxy group having 3 to 10 carbon atoms include a cyclopentenyloxy group and a cyclohexenyloxy group.

[0068] 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. Among these, a phenyl group, a 2-fluorophenyl group, and a pentafluorophenyl group are preferable.

[0069] 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 preferable.

[0070] More specifically, examples of the anion of the compound represented by the above general formula [2] include the following compounds No. 2-1 to No. 2-17, etc. However, the compound represented by the general formula [2] used in the present invention is not limited in any way by the following examples.

[0071] [ka]

[0072] 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 a hydrocarbon group having 6 or less carbon atoms which may contain a fluorine atom. When the number of carbon atoms of the hydrocarbon group is more than 6, the internal resistance when a coating is formed on an electrode tends to be relatively large. When the number of carbon atoms is 6 or less, the internal resistance tends to be smaller, which is preferable, and in particular, when the number of carbon atoms is 6 or less, it is preferable that the methyl group, the ethyl group, the n-propyl group, the vinyl group, the allyl group, the ethynyl group, the 2-propynyl group, the phenyl group, the trifluoromethyl group, the 2,2-difluoroethyl group, the 2,2,2-trifluoroethyl group, the 2,2,3,3-tetrafluoropropyl group, the 1,1,1,3,3,3-hexafluoroisopropyl group, or an alkoxy group, an alkenyloxy group, or an alkynyloxy group derived from these groups, since a nonaqueous electrolyte secondary battery capable of exhibiting a good balance between cycle characteristics and internal resistance characteristics can be obtained.

[0073] 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.

[0074] The compound represented by the general formula [2] is preferably one that has been highly purified by a general refining operation. In particular, the Cl (chlorine) content in the compound as a raw material before dissolving in an electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and even more preferably 100 mass ppm or less. If a salt having an imide anion with a high concentration of Cl (chlorine) is used, it is not preferable because it tends to corrode battery components.

[0075] Similarly, the content of free acid in the compound as a raw material before dissolving in the electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and even more preferably 100 mass ppm or less. If a salt having an imide anion in which free acid remains at a high concentration is used, it is not preferable because it tends to corrode battery components. In this specification, the free acid refers to an acid component present in the solution, and examples thereof include hydrogen fluoride (HF), sulfuric acid, and fluorosulfonic acid.

[0076] In order to obtain a highly pure compound represented by the above general formula [2] or to adjust the content of chlorine or free acid to the above range, a purification operation can be carried out. The purification procedure may be any procedure commonly used in organic synthesis, and is not particularly limited. Specific examples include washing, separation, concentration, distillation, recrystallization, activated carbon treatment, column chromatography, and the like.

[0077] The compound represented by the above general formula [2] can be produced by various methods. The production method is not limited, but for example, it can be obtained by the following method. The corresponding sulfonylamide (H 2 NSO 2 R 1 ) and the corresponding sulfonyl halides (R 2 SO 2 X; X is a halogen atom) in the presence of an organic base or an inorganic base. As disclosed in JP-A-2004-522681, a method in which a salt having an imide anion in which the fluorine atom of the corresponding salt having an imide anion is replaced by a halogen atom other than a fluorine atom is obtained by the above-mentioned method, and then a fluorination reaction is carried out.

[0078] [Regarding the compound represented by the general formula [3]] In the above general formula [3], R 3 ~R 6 It is important that at least one of the above is a fluorine atom. Although the reason is not clear, when at least one of the above is a fluorine atom, the effect of suppressing the internal resistance of a battery using the electrolyte is large.

[0079] R 3 ~R 6 In the organic group represented by the formula (I), a fluorine atom, an oxygen atom, a cyano group or an unsaturated bond may be present.

[0080] In the present invention, "a cyano group is present in an organic group" means that at least one hydrogen atom in the organic group is substituted with a cyano group.

[0081] 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.

[0082] 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-tetrafluoropropoxy group, a 1,1,1,3,3,3-hexafluoroisopropoxy group, and a 2-cyanoethoxy group. Among 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.

[0083] 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.

[0084] 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. Among these, an allyloxy group is preferable.

[0085] 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.

[0086] 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. Of these, the 2-propynyloxy group is preferred.

[0087] Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group and a cyclohexyl group.

[0088] Examples of the cycloalkoxy group having 3 to 10 carbon atoms include a cyclopentyloxy group and a cyclohexyloxy group.

[0089] Examples of the cycloalkenyl group having 3 to 10 carbon atoms include a cyclopentenyl group and a cyclohexenyl group.

[0090] Examples of the cycloalkenyloxy group having 3 to 10 carbon atoms include a cyclopentenyloxy group and a cyclohexenyloxy group.

[0091] 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.

[0092] 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 preferable.

[0093] More specifically, examples of the anion of the compound represented by the above general formula [3] include the following compounds No. 3-1 to No. 3-13. However, the compound represented by the general formula [3] used in the present invention is not limited to the following examples. In the formula, Me represents a methyl group.

[0094] [ka]

[0095] In the above general formula [3], R 3 ~R 6 At least one of R is a fluorine atom, 3 ~R 6It is preferable that at least one of the groups is selected from a hydrocarbon group having 6 or less carbon atoms which may contain a fluorine atom. If the number of carbon atoms of the hydrocarbon group is more than 6, the internal resistance when a coating is formed on an electrode tends to be relatively large. If the number of carbon atoms is 6 or less, the internal resistance tends to be smaller, which is preferable, and in particular, if the group is 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 these groups, it is preferable that a nonaqueous electrolyte secondary battery capable of exhibiting a good balance between cycle characteristics and internal resistance characteristics is obtained.

[0096] 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.

[0097] The compound represented by the general formula [3] is preferably one that has been highly purified by a general refining operation. In particular, the Cl (chlorine) content in the compound as a raw material before dissolving in an electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and even more preferably 100 mass ppm or less. If a salt having an imide anion with a high concentration of Cl (chlorine) is used, it is not preferable because it tends to corrode battery components.

[0098] Similarly, the content of free acid in the compound as a raw material before dissolving in the electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and further preferably 100 mass ppm or less. Use of a salt having an imide anion in which free acid remains at a high concentration is undesirable because it tends to corrode battery components.

[0099] In order to obtain a highly pure compound represented by the above general formula [3], or to adjust the content of chlorine or free acid to the above range, a purification operation can be carried out. This purification procedure may be any procedure commonly used in organic synthesis, and is not particularly limited. Specific examples include washing, separation, concentration, distillation, activated carbon treatment, column chromatography, and the like.

[0100] The compound represented by the above general formula [3] can be produced by various methods. The production method is not limited, but for example, it can be obtained by the following method. The corresponding phosphoramide (H 2 NP(=O)R 3 R 4 ) and the corresponding phosphoryl halide (R 5 R 6 A method in which P(=O)X (X is a halogen atom) is reacted in the presence of an organic base or an inorganic base. As shown in Z. anorg. allg. chem., 621, 894-900, 1995, a method in which a salt having an imide anion in which the fluorine atom of the corresponding salt having an imide anion is replaced by a halogen atom other than a fluorine atom is obtained by the above method, and then a fluorination reaction is carried out. R 3 ~R 6 When a part of R contains an alkoxy group, 3 ~R 6 A method in which an imide anion in which R is a halogen atom is obtained, and then the imide anion is reacted with a corresponding alcohol in the presence of an inorganic base or an organic base.

[0101] [Regarding the compound represented by the general formula [4]] In the above general formula [4], R7 ~R 9 It is important that at least one of the above is a fluorine atom. Although the reason is not clear, when at least one of the above is a fluorine atom, the effect of suppressing the internal resistance of a battery using the electrolyte is large.

[0102] R 7 ~R 9 In the organic group represented by the formula (I), a fluorine atom, an oxygen atom or an unsaturated bond may be present.

[0103] In addition, 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 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. Among these, a methyl group and a trifluoromethyl group are preferred.

[0104] 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. Among 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.

[0105] 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. Among these, the vinyl group is preferable.

[0106] 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. Among these, an allyloxy group is preferable.

[0107] 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.

[0108] 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. Among these, the 2-propynyloxy group is preferable.

[0109] Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group and a cyclohexyl group.

[0110] Examples of the cycloalkoxy group having 3 to 10 carbon atoms include a cyclopentyloxy group and a cyclohexyloxy group.

[0111] Examples of the cycloalkenyl group having 3 to 10 carbon atoms include a cyclopentenyl group and a cyclohexenyl group.

[0112] Examples of the cycloalkenyloxy group having 3 to 10 carbon atoms include a cyclopentenyloxy group and a cyclohexenyloxy group.

[0113] 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.

[0114] 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 and the tolyloxy group are preferred.

[0115] More specifically, examples of the anion of the compound represented by the above general formula [4] include the following compounds No. 4-1 to No. 4-18. However, the compound represented by the general formula [4] used in the present invention is not limited by the following examples. In the formula, Me represents a methyl group, and Et represents an ethyl group.

[0116] [ka]

[0117] In the above general formula [4], R 7 ~R 9 At least one of R is a fluorine atom, 7 ~R 9 It is preferable that at least one of the groups is selected from a hydrocarbon group having 6 or less carbon atoms which may contain a fluorine atom. If the number of carbon atoms of the hydrocarbon group is more than 6, the internal resistance when a coating is formed on an electrode tends to be relatively large. If the number of carbon atoms is 6 or less, the internal resistance tends to be smaller, which is preferable, and in particular, if the group is 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 these groups, it is preferable that a nonaqueous electrolyte secondary battery capable of exhibiting a good balance between cycle characteristics and internal resistance characteristics is obtained.

[0118] 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.

[0119] The compound represented by the general formula [4] is preferably one that has been highly purified by a general refining operation. In particular, the Cl (chlorine) content in the compound as a raw material before dissolving in the electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and even more preferably 100 mass ppm or less. If a salt having an imide anion with a high concentration of Cl (chlorine) is used, it is not preferable because it tends to corrode battery components.

[0120] Similarly, the content of free acid in the compound as a raw material before dissolving in the electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and further preferably 100 mass ppm or less. Use of a salt having an imide anion in which free acid remains at a high concentration is undesirable because it tends to corrode battery components.

[0121] In order to obtain a highly pure compound represented by the above general formula [4], or to adjust the chlorine or free acid content to the above range, a purification operation can be carried out. This purification procedure may be any procedure commonly used in organic synthesis, and is not particularly limited. Specific examples include washing, separation, concentration, distillation, activated carbon treatment, column chromatography, and the like.

[0122] The compound represented by the above general formula [4] can be produced by various methods. The production method is not limited, but for example, it can be obtained by any of the following methods. The corresponding phosphoramide (H 2 NP(=O)R 7 R 8 ) and the corresponding sulfonyl halides (R 9 SO 2 X; X is a halogen atom) in the presence of an organic base or an inorganic base. The corresponding sulfonylamide (H 2 NSO 2 R 9 ) and the corresponding phosphoryl halide (R 7 R 8 A method in which P(=O)X (X is a halogen atom) is reacted in the presence of an organic base or an inorganic base. As disclosed in CN Patent Publication No. 101654229 or CN Patent Publication No. 102617414, a compound in which the fluorine atom of the corresponding compound is replaced with a halogen atom other than a fluorine atom is obtained by the above method, and then the compound is subjected to a fluorination reaction.

[0123] In addition, in the above 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 especially preferably lithium ions.

[0124] [Regarding the compound represented by the general formula [5]] In the above general formula [5], R 10Examples of the group having a carbon-carbon unsaturated bond represented by the formula include alkenyl groups having 2 to 8 carbon atoms, such as vinyl groups, allyl groups, 1-propenyl groups, 2-propenyl groups, isopropenyl groups, 2-butenyl groups, and 1,3-butadienyl groups, or alkenyloxy groups derived from these groups; alkynyl groups having 2 to 8 carbon atoms, such as ethynyl groups, 2-propynyl groups, and 1,1-dimethyl-2-propynyl groups, or alkynyloxy groups derived from these groups; aryl groups having 6 to 12 carbon atoms, such as phenyl groups, tolyl groups, and xylyl groups, or aryloxy groups derived from these groups. The above groups may also have fluorine atoms and oxygen atoms. Incidentally, having a fluorine atom means that a hydrogen atom bonded to a carbon atom is replaced with a fluorine atom, and having an oxygen atom means that an oxygen atom exists as an ether bond between the carbon-carbon bonds. Among them, a group containing a carbon-carbon unsaturated bond having 6 or less carbon atoms is preferred. If the number of carbon atoms is more than 6, the internal resistance when a coating is formed on an electrode tends to be relatively high. A group containing a carbon-carbon unsaturated bond having 6 or less carbon atoms is preferred because the internal resistance tends to be smaller, specifically, a group selected from the group consisting of a vinyl group, an allyl group, a 1-propenyl group, a 2-propenyl group, an ethynyl group, and a 2-propynyl group is preferred, and a vinyl group is particularly preferred.

[0125] In addition, in the above general formula [5], R 11Examples of the alkyl group represented by the formula (I) include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, and pentyl groups. The above groups may also have a fluorine atom and an oxygen atom. Examples of groups having an oxygen atom include alkoxy groups derived from the above alkyl groups. Groups selected from alkyl groups and alkoxy groups tend to have smaller resistance when a coating is formed on an electrode, and as a result, are preferred from the viewpoint of output characteristics. In particular, a group selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, a 2,2,2-trifluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,1-trifluoroisopropyl group, a 1,1,1,3,3,3-hexafluoroisopropyl group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropoxy group, a 2,2,3,3,3-pentafluoropropoxy group, a 1,1,1-trifluoroisopropoxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group is preferred, since this allows for a nonaqueous electrolyte battery to be obtained that is more excellent in high-temperature cycle characteristics and high-temperature storage characteristics without increasing the internal resistance when a coating is formed on an electrode.

[0126] The number of groups having a carbon-carbon unsaturated bond represented by a in the above general formula [5] must be an integer of 2 to 4 in order to form a film on the electrode and thereby to achieve the object of the present invention, 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 unclear, it is thought that this is because it is easier to form a stronger film.

[0127] More specifically, examples of the compound represented by the above general formula [5] include the following compounds No. 5-1 to No. 5-20, etc. However, the silane compound used in the present invention is not limited in any way by the following examples.

[0128] [ka]

[0129] As the compound represented by the above general formula [5], among the above 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 preferable 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 preferable.

[0130] The compound represented by the above general formula [5] is preferably one that has been highly purified by a general purification operation. In particular, the Cl (chlorine) content in the compound as a raw material before dissolving in the electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and even more preferably 100 mass ppm or less. If a salt having an imide anion in which Cl (chlorine) remains at a high concentration is used, it is not preferable because it tends to corrode battery components.

[0131] Similarly, the content of free acid in the compound as a raw material before dissolving in the electrolyte is preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and further preferably 100 mass ppm or less. Use of a salt having an imide anion in which free acid remains at a high concentration is undesirable because it tends to corrode battery components.

[0132] In order to obtain a highly pure compound represented by the above general formula [5], or to adjust the chlorine or free acid content to the above range, a purification operation can be carried out. This purification procedure may be any procedure commonly used in organic synthesis, and is not particularly limited. Specific examples include washing, separation, concentration, distillation, activated carbon treatment, column chromatography, and the like.

[0133] The compound represented by the above general formula [5] can be produced by a method of reacting a silicon compound having a silanol group or a hydrolyzable group with an organometallic reagent containing a carbon-carbon unsaturated bond to substitute the silanol group or the hydrolyzable group in the silicon compound with a carbon-carbon unsaturated bond group, as described in, for example, JP-A-10-139784, Journal of Organic Chemistry (1957), vol. 22, p. 1200-2, or Chemicke Zvesti (1964), vol. 18, p. 21-7, to produce a silicon compound containing a carbon-carbon unsaturated bond.

[0134] In addition, difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, or fluorosulfonate can also be used as the second additive. These compounds can also improve high-temperature storage properties and low-temperature properties when used in combination with the first additive.

[0135] The content of the above (II) relative to the total amount of the above (I) to (IV) is preferably 0.005 mass % or more, more preferably 0.05 mass % or more, and more preferably 0.1 mass % or more, and is preferably 12.0 mass % or less, more preferably 10.0 mass % or less, and more preferably 5.0 mass % or less. When the content is 0.005% by mass or more, the effect of improving the battery characteristics tends to be easily obtained.When the content is 12.0% by mass or less, deterioration of characteristics at low temperatures due to an increase in the viscosity of the electrolyte solution is unlikely to occur. The content of the above (II) is preferably within a range not exceeding 12.0% by mass, and one type may be used alone, or two or more types may be mixed in any combination and ratio depending on the application.

[0136] (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 cyclic carbonates such as propylene carbonate (hereinafter sometimes referred to as "PC"), ethylene carbonate (hereinafter sometimes referred to as "EC"), and butylene carbonate; 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"); cyclic esters such as γ-butyrolactone and γ-valerolactone; chain esters such as methyl acetate, methyl propionate, and ethyl propionate (hereinafter sometimes referred to as "EP"); cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, and dioxane; chain ethers such as dimethoxyethane and diethyl ether; sulfone compounds and sulfoxide compounds such as dimethyl sulfoxide and sulfolane; and the like. Ionic liquids and the like can also be mentioned. The nonaqueous organic solvent used in the present invention may be used alone or in any combination and ratio of two or more kinds according to the purpose. 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 above-mentioned solutes.

[0137] For example, it is preferable to use a non-aqueous organic solvent that contains one or more cyclic carbonates with high dielectric constants and one or more chain carbonates or chain esters with low liquid viscosity, since this increases the ionic conductivity of the electrolyte. Specifically, it is more preferable to use a non-aqueous organic solvent that contains the following combinations:

[0138] (1) Combination of EC and EMC, (2) A combination of EC and DEC, (3) A combination of EC, DMC and EMC, (4) A 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

[0139] (IV) Solutes Specific examples of solutes in the non-aqueous electrolyte of the present invention include LiPF in the case of lithium batteries and lithium ion batteries. 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiAlO 2 , LiAlCl 4 , LiCl, LiI, LiC(CF 3 SO 2 ) 3 , LiPF 3 (C 3 F 7 ) 3 , LiB(CF 3 ) 4 , LiBF 3 (C 2 F 5 ) and the like are typical electrolyte salts. In the case of sodium ion batteries, NaPF 6 , NaBF 4 , NaSbF 6 , NaAsF 6 , NaClO 4 , NaCF 3 SO 3 , NaC 4 F 9SO 3 , NaAlO 2 , NaAlCl 4 , NaCl, NaI, NaC(CF 3 SO 2 ) 3 , NaPF 3 (C 3 F 7 ) 3 , NaB(CF 3 ) 4 , NaBF 3 (C 2 F 5 ) and the like. These solutes may be used alone or in any combination or ratio of two or more depending on the application. Among them, in the case of lithium batteries and lithium ion batteries, in terms of the energy density, output characteristics, life, etc. of the battery, at least LiPF 6 It is preferable that the compound contains LiPF. 6 When used in combination with other (IV) components, the other (IV) components are LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiAlO 2 , LiAlCl 4 It is preferable to use at least one selected from the group consisting of LiCl and LiI.

[0140] In the case of a sodium ion battery, the above (IV) is at least NaPF 6 It is preferable that the compound contains NaPF. 6 When used in combination with other (IV) components, the other (IV) components include NaBF 4 , NaSbF 6 , NaAsF 6 , NaClO 4 , NaCF 3 SO 3 , NaC4 F 9 SO 3 , NaAlO 2 , NaAlCl 4 It is preferable to use at least one selected from the group consisting of NaCl and NaI.

[0141] (IV) The concentration of the solute is not particularly limited, but the suitable lower limit of the solute concentration in the nonaqueous electrolyte is 0.5 mol / L or more, preferably 0.7 mol / L or more, more preferably 0.9 mol / L or more, and the suitable upper limit is 2.5 mol / L or less, preferably 2.0 mol / L or less, more preferably 1.5 mol / L or less.

[0142] The liquid temperature when the solute is dissolved in the nonaqueous organic solvent is not particularly limited, but is preferably from -20 to 80°C, more preferably from 0 to 60°C.

[0143] Other additives or ingredients The above is an explanation of the basic configuration of the nonaqueous electrolyte solution of the present invention. However, as long as the gist of the present invention is not impaired, additives that are generally used in the nonaqueous electrolyte solution of the present invention may be added in any ratio.

[0144] Specific examples include vinylene carbonate (hereinafter sometimes referred to as "VC"), vinylene carbonate oligomer (polystyrene equivalent number average molecular weight of 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, and 1,2-ethane disulfonic acid. Examples of compounds that have an overcharge prevention effect, a negative electrode coating effect, or a positive electrode protection effect include anhydrides, methanesulfonyl fluoride, tris(trimethylsilyl)borate, succinonitrile, (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.

[0145] In addition, carboxylates such as lithium acrylate, sodium acrylate, lithium methacrylate, and sodium methacrylate, and sulfates such as lithium methyl sulfate, sodium methyl sulfate, lithium ethyl sulfate, and sodium methyl sulfate may be added.

[0146] Also, as in the case of use in a non-aqueous electrolyte secondary battery called a lithium polymer battery, the non-aqueous electrolyte may be quasi-solidified with a gelling agent or a crosslinked polymer and used.

[0147] In addition, the nonaqueous electrolyte of the present invention may contain a total of four or more kinds of alkali metal salts in combination, depending on the required characteristics, such as the above (IV) solute (lithium salt, sodium salt), the above (II) salt having an imide anion represented by the general formulas [2] to [4] (lithium salt, sodium salt), difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate (all of which are lithium salt or sodium salt).

[0148] For example, when the above components (II) and (IV) contain four kinds of lithium salts, LiPF 6 As the second solute, 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, and as a second additive, lithium salts having imide anions represented by the general formulas [2] to [4], lithium difluoro(oxalato)borate (hereinafter referred to as "LiBF 2 (C 2 O 4 ) and lithium bis(oxalato)borate (hereinafter referred to as "LiB(C 2 O 4 ) 2 "), lithium tetrafluoro(oxalato)phosphate (hereinafter referred to as "LiPF 4 (C 2 O 4 ) and lithium difluorobis(oxalato)phosphate (hereinafter referred to as "LiPF 2 (C 2 O 4 ) 2 "), lithium tris(oxalato)phosphate (hereinafter referred to as "LiP(C2 O 4 ) 3 "), lithium difluorophosphate (hereinafter referred to as "LiPO 2 F 2 "), and lithium fluorosulfonate (hereinafter "LiSO 3 F) or LiPF as the first solute. 6 using a lithium salt having an imide anion represented by the above general formulas [2] to [4], LiBF 2 (C 2 O 4 ), LiB(C 2 O 4 ) 2 , LiPF 4 (C 2 O 4 ), LiPF 2 (C 2 O 4 ) 2 , LiP(C 2 O 4 ) 3 , LiPO 2 F 2 , and LiSO 3 It is considered that three types from F can be used.

[0149] in particular, (1) LiPF 6 , the Li salt of compound No. 2-1, the Li salt of compound No. 2-6, and LiPF 2 (C 2 O 4 ) 2 A combination of (2) LiPF 6 , LiBF 4 , the Li salt of compound No. 2-1, and LiPO 2 F 2 A combination of (3) LiPF 6 , the Li salt of compound No. 2-1, the Li salt of compound No. 3-1, and LiPO 2 F 2 A combination of (4) LiPF 6 , Li salt of compound No. 3-1, LiPF2 (C 2 O 4 ) 2 , and LiPO 2 F 2 A combination of (5) LiPF 6 , Li salt of compound No. 3-1, LiB(C 2 O 4 ) 2 , and LiPO 2 F 2 A combination of (6) LiPF 6 , Li salt of compound No. 4-1, LiPF 2 (C 2 O 4 ) 2 , and LiPO 2 F 2 A combination of It is preferable to contain four kinds of lithium salts as described above, because the effect of suppressing the increase in internal resistance at low temperatures is greater. The above combination is an example, and it is of course possible to use combinations other than the above. In addition, additives other than the above may be further added in combination as necessary.

[0150] Furthermore, the total number of alkali metal salts in the components (I) and (IV) may be five or more. For example, the above components (I) and (IV) may include LiPF as the first solute. 6 and further using one of the second solutes, a lithium salt having an imide anion represented by the above general formulas [2] to [4], LiBF 2 (C 2 O 4 ), LiB(C 2 O 4 ) 2 , LiPF 4 (C 2 O 4 ), LiPF 2 (C 2 O 4 ) 2 , LiP(C 2 O 4 ) 3 , LiPO 2 F 2 , LiSO3 Use three types from F. Or LiPF as the first solute 6 using a lithium salt having an imide anion represented by the above general formulas [2] to [4], LiBF 2 (C 2 O 4 ), LiB(C 2 O 4 ) 2 , LiPF 4 (C 2 O 4 ), LiPF 2 (C 2 O 4 ) 2 , LiP(C 2 O 4 ) 3 , LiPO 2 F 2 , and LiSO 3 It is possible to use four types from F.

[0151] in particular, (1) LiPF 6 , Li salt of compound No. 2-1, Li salt of compound No. 2-6, LiPF 4 (C 2 O 4 ), and LiPF 2 (C 2 O 4 ) 2 In combination with (2) LiPF 6 , LiBF 4 , Li salt of compound No. 2-1, LiB(C 2 O 4 ) 2 , and LiPO 2 F 2 A combination of (3) LiPF 6 , Li salt of compound No. 2-1, LiBF 2 (C 2 O 4 ), LiPO 2 F 2 , and LiSO 3 Combination of F. (4) LiPF 6, Li salt of compound No. 2-1, Li salt of compound No. 3-1, LiB(C 2 O 4 ) 2 , and LiPO 2 F 2 A combination of (5) LiPF 6 , Li salt of compound No. 3-1, LiPF 4 (C 2 O 4 ), LiPF 2 (C 2 O 4 ) 2 , and LiPO 2 F 2 A combination of (6) LiPF 6 , Li salt of compound No. 3-1, Li salt of compound No. 3-4, LiPF 4 (C 2 O 4 ), and LiPF 2 (C 2 O 4 ) 2 A combination of (7) LiPF 6 , Li salt of compound No. 3-1, Li salt of compound No. 4-1, LiPF 2 (C 2 O 4 ) 2 , and LiSO 3 Combination of F. (8) LiPF 6 , Li salt of compound No. 4-1, LiPF 4 (C 2 O 4 ), LiPF 2 (C 2 O 4 ) 2 , and LiPO 2 F 2 A combination of (9) LiPF 6 , Li salt of compound No. 4-1, Li salt of compound No. 4-5, LiBF 2 (C 2 O 4 ), and LiPO 2 F 2 A combination of (10) LiPF 6 , Li salt of compound No. 4-6, LiB(C 2 O 4 ) 2 , LiPO 2 F 2 , and LiSO 3 Combination of F. It is preferable to contain five kinds of lithium salts as described above, since the effect of suppressing gas generation at high temperatures is greater. The above combinations are only examples, and combinations other than the above may be used. In addition, lithium salts other than the above (the above additives) may be further added in combination as necessary.

[0152] 2. Non-aqueous electrolyte secondary batteries Next, the configuration of the nonaqueous electrolyte secondary battery of the present invention will be described. The nonaqueous electrolyte secondary battery of the present invention is characterized by using the nonaqueous electrolyte of the present invention described above, and other components are the same as those used in general nonaqueous electrolyte secondary batteries.

[0153] The nonaqueous electrolyte secondary battery may be a nonaqueous electrolyte secondary battery including (a) the above-mentioned nonaqueous electrolyte, (b) a positive electrode, (c) a negative electrode, and (d) a separator, as described below.

[0154] [(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.

[0155] [Cathode active material] In the case of a lithium ion secondary battery in which the cations in the nonaqueous electrolyte are mainly lithium, (a) the positive electrode active material constituting the positive electrode is not particularly limited as long as it is a material capable of being charged and discharged. Examples of the positive electrode active material include those 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.

[0156] ((A) Lithium transition metal composite oxide) Cathode active material (A) Examples of lithium transition metal composite oxides that contain at least one metal selected from nickel, manganese, and cobalt and have a layered structure include 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. In addition, some of the transition metal atoms that are the main components of these lithium transition metal composite oxides may be replaced with other elements such as Al, Ti, V, Cr, Fe, Cu, Zn, Mg, Ga, Zr, Si, B, Ba, Y, Sn, etc.

[0157] Specific examples of lithium-cobalt composite oxide and lithium-nickel composite oxide are LiCoO 2 , LiNiO 2 Lithium cobalt oxide (LiCo) 0.98 Mg 0.01 Zr 0.01 O 2 , LiCo 0.98 Mg 0.01 Al 0.01 O 2 , LiCo 0.975 Mg 0.01 Zr 0.005 Al 0.01 O 2 Lithium cobalt oxide having a rare earth compound fixed to the surface thereof, as described in WO2014 / 034043, may also be used. In addition, as described in JP2002-151077A, LiCoO 2 The particle powder may have a part of its surface coated with aluminum oxide.

[0158] 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 O 2 (6) In formula (6), M 1 is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, and B, a satisfies the conditions of 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 O 2 , LiNi 0.85 Co 0.10 Al 0.05 O 2 , LiNi 0.87 Co 0.10 Al 0.03 O 2 , LiNi 0.90 Co 0.07 Al 0.03 O 2 , LiNi 0.6 Co 0.3 Al 0.1 O 2 etc.

[0159] Specific examples of lithium-cobalt-manganese composite oxides and lithium-nickel-manganese composite oxides include LiCo 0.5 Mn 0.5 O 2 Or LiNi 0.5 Mn 0.5 O 2 etc.

[0160] 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 M2 h O 2 (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.

[0161] The lithium-nickel-manganese-cobalt composite oxide preferably contains manganese in the range shown in general formula (7) in order to enhance the structural stability and improve the safety of lithium secondary batteries at high temperatures, and more preferably further contains cobalt in the range shown in general formula (7) in order to enhance the high-rate characteristics of lithium ion secondary batteries. Specifically, for example, Li[Ni 1 / 3 Mn 1 / 3 Co 1 / 3 ]O 2 , Li[Ni 0.45 Mn 0.35 Co 0.2 ]O 2 , Li[Ni 0.5 Mn 0.3 Co 0.2 ]O 2 , Li[Ni 0.6 Mn 0.2 Co 0.2 ]O 2 , Li[Ni 0.8 Mn 0.1 Co 0.1 ]O 2 , Li[Ni 0.49 Mn 0.3 Co 0.2 Zr 0.01 ]O 2 , Li[Ni 0.49 Mn 0.3 Co 0.2 Mg 0.01 ]O 2 , Li[Ni 0.8 Mn 0.1 Co 0.1 ]O 2 etc.

[0162] ((B) Lithium manganese composite oxide with spinel structure) Cathode active material (B) An example of the lithium manganese composite oxide having a spinel structure is a spinel-type lithium manganese composite oxide represented by the general formula (8). Li j (M 2-k M 3 k )O 4 (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, LiMn 2 O 4 , LiMn 1.95 Al 0.05 O 4 , LiMn 1.9 Al 0.1 O 4 , LiMn 1.9 Ni 0.1 O 4 , LiMn 1.5 Ni 0.5 O 4 etc.

[0163] ((C) Lithium-containing olivine-type phosphate) Cathode active material (C) An example of the lithium-containing olivine-type phosphate is represented by the general formula (9). Life 1-n M 4 n PO 4 (9) In 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, LiFePO 4 , LiCoPO4 , LiNiPO 4 , LiMnPO 4 etc. can be mentioned, among which LiFePO 4 and / or LiMnPO 4 are preferred.

[0164] ((D) Lithium-excess layered transition metal oxide) Positive electrode active material (D) Examples of the lithium-excess layered transition metal oxide having a layered rock salt-type structure include those represented by the general formula (10). xLiM 5 O 2 ·(1 - x)Li 2 M 6 O 3 (10) In formula (10), x is a number satisfying 0 < x < 1, and M 5 is at least one metal element with an average oxidation number of 3 + , and M 6 is at least one metal element with an average oxidation number of 4 + . In formula (10), M 5 is preferably one metal element selected from trivalent Mn, Ni, Co, Fe, V, and Cr, but the average oxidation number may also be made trivalent with an equal amount of divalent and tetravalent metals. Also, in formula (10), M 6 is preferably one or more metal elements selected from Mn, Zr, and Ti. Specifically, 0.5[LiNi 0.5 Mn 0.5 O 2 ·0.5[Li 2 MnO 3 , 0.5[LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 ·0.5[Li 2 MnO 3 , 0.5[LiNi 0.375 Co 0.25 Mn 0.375 O 2 ·0.5[Li 2 MnO 3], 0.5[LiNi 0.375 Co 0.125 Fe 0.125 Mn 0.375 O 2 ]·0.5[Li 2 MnO 3 ], 0.45[LiNi 0.375 Co 0.25 Mn 0.375 O 2 ]·0.10[Li 2 TiO 3 ]·0.45[Li 2 MnO 3 ] etc. The positive electrode active material (D) represented by the general formula (10) is known to exhibit high capacity upon high-voltage charging of 4.4 V (based on Li) or more (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-2008-270201, WO2013 / 118661, JP-A-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 may also be included, such as FeS 2 , TiS 2 , V 2 O 5 , MoO 3 , MoS 2 Examples of the material include transition element chalcogenides such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole, conductive polymers such as activated carbon, polymers that generate radicals, and carbon materials.

[0165] [Positive electrode current collector] (a) The positive electrode has a positive electrode current collector. As the positive electrode current collector, for example, aluminum, stainless steel, nickel, titanium, or an alloy thereof can be used.

[0166] [Cathode active material layer] (a) The positive electrode is, 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.

[0167] Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, and styrene butadiene rubber (SBR) resin.

[0168] As the conductive agent, for example, carbon materials such as acetylene black, ketjen black, carbon fiber, graphite (granular graphite, flake graphite), etc. are usable. In the positive electrode, it is preferable to use acetylene black or ketjen black, which has low crystallinity.

[0169] [(C) Negative electrode] (c) The negative electrode preferably contains at least one type of negative electrode active material.

[0170] [Negative electrode active material] In the case of a lithium ion secondary battery in which the cations in the non-aqueous electrolyte are mainly lithium, the negative electrode active material constituting the negative electrode (c) is capable of doping and dedoping lithium ions, and examples thereof include (E) a carbon material having a d value of 0.340 nm or less in the lattice plane (002 plane) in X-ray diffraction, (F) a carbon material having a d value of more than 0.340 nm in the lattice plane (002 plane) 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 an alloy containing these metals, or an alloy of these metals or alloys and lithium, and (I) a material containing at least one selected from lithium titanium oxide. These negative electrode active materials can be used alone or in combination of two or more. In addition, lithium metal, metal nitride, tin compound, conductive polymer, etc. may also be used.

[0171] ((E) Carbon material with d value of lattice plane (002 plane) of 0.340 nm or less in X-ray diffraction) Negative electrode active material (E) Examples of carbon materials having a lattice plane (002 plane) d value of 0.340 nm or less in X-ray diffraction include pyrolytic carbons, cokes (e.g., pitch coke, needle coke, petroleum coke, etc.), graphites, organic polymer compound baked bodies (e.g., phenol resin, furan resin, etc. baked at an appropriate temperature and carbonized), carbon fibers, activated carbon, etc., which may be graphitized. The carbon materials in question are those having a (002) plane interplanar spacing (d002) of 0.340 nm or less as measured by X-ray diffraction, and among them, those having a true density of 1.70 g / cm 3 Graphite having the above properties or a highly crystalline carbon material having properties similar thereto is preferred.

[0172] ((F) Carbon material with d value of lattice plane (002 plane) exceeding 0.340 nm in X-ray diffraction) Negative electrode active material (F) Carbon materials with a d value of the lattice plane (002 plane) exceeding 0.340 nm in X-ray diffraction include amorphous carbon, which is a carbon material in which the stacking order hardly changes 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.

[0173] ((G) Oxide of one or more metals selected from Si, Sn and Al) Negative electrode active material (G) Examples of the oxide of one or more metals selected from Si, Sn, and Al include silicon oxide, tin oxide, and the like, which can be doped and dedoped with lithium ions. Ultrafine particles of Si are SiO 2 SiO with a structure dispersed in x When this material is used as the negative electrode active material, charging and discharging are smooth because the Si that reacts with Li is in the form of ultrafine particles, while the SiO xSince 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 By using the graphite of the negative electrode active material (E) in a specific ratio in combination with the negative electrode active material, it is possible to achieve both high capacity and good charge / discharge cycle characteristics.

[0174] ((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) Negative electrode active material (H) Examples of the one or more metals selected from Si, Sn, and Al, or alloys containing these metals, or alloys of these metals or alloys with lithium include metals such as silicon, tin, and aluminum, silicon alloys, tin alloys, and aluminum alloys, and materials in which these metals or alloys are alloyed with lithium during charging and discharging can also be used. Preferred specific examples of these include metal elements (e.g., powders) such as silicon (Si) and tin (Sn), metal alloys, compounds containing the metals, and alloys containing tin (Sn) and cobalt (Co) in the metals, as described in WO2004 / 100293 and JP2008-016424. When the metals are used in electrodes, they are preferred because they can achieve high charge capacity and the volume expansion and contraction associated with charging and discharging is relatively small. In addition, it is known that when these metals are used in the negative electrode of a lithium ion secondary battery, they are alloyed with Li during charging, resulting in high charge capacity, which is also 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, for example, WO2004 / 042851, WO2007 / 083155, and the like, may also be used.

[0175] ((I) Lithium Titanium Oxide) Negative electrode active material (I) Examples of the 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 Li 4+α Ti 5 O 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 Ti 3 O 7 (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-2007-018883 and JP-A-2009-176752. 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, the negative electrode active material is, for example, hard carbon or TiO 2 , V 2 O 5 , MoO 3 For example, in the case of a sodium ion secondary battery in which the cations in the non-aqueous electrolyte are mainly sodium, NaFeO 2 , NaCrO 2 , NaNiO 2 , NaMnO 2 , NaCoO 2 Sodium-containing transition metal composite oxides such as Fe, Cr, Ni, Ti, Mn, Co, etc., are mixed with multiple transition metals such as Fe, Cr, Ni, Ti, Mn, Co, etc. (e.g., NaNi 0.5 Ti 0.3 Mn 0.2 O 2 ), those in which a part of the transition metal in the sodium-containing transition metal composite oxide is replaced by a metal other than the transition metal, 2 FeP 2 O 7 , NaCo 3 (PO 4 ) 2 P 2 O 7Phosphates of transition metals such as TiS 2 , FeS 2 or conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole; activated carbon; polymers that generate radicals; and carbon materials.

[0176] [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.

[0177] [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.

[0178] Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, and styrene butadiene rubber (SBR) resin.

[0179] 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.

[0180] [Method of manufacturing electrodes ((a) positive electrode and (c) negative electrode)] The electrode can be obtained, for example, by dispersing and kneading the active material, the binder, and optionally the conductive agent in a predetermined blending amount in a solvent such as N-methyl-2-pyrrolidone (NMP) or water, applying the obtained paste to a current collector, and drying to form an active material layer. The obtained electrode is preferably compressed by a method such as a roll press to adjust the density of the electrode to an appropriate value.

[0181] [(D) Separator] The non-aqueous electrolyte secondary battery includes a separator (d). The separator for preventing contact between the positive electrode (b) and the negative electrode (c) is a non-woven fabric or porous sheet made of polyolefin such as polypropylene or polyethylene, cellulose, paper, glass fiber, etc. These films are preferably microporous so that the electrolyte can penetrate and ions can easily pass through.

[0182] Examples of the polyolefin separator include a film that electrically insulates the positive electrode and the negative electrode, such as a microporous polymer film, such as a porous polyolefin film, and is permeable to lithium ions. Specific examples of the porous polyolefin film include a porous polyethylene film alone, or a multilayer film formed by stacking a porous polyethylene film and a porous polypropylene film. Also included are films obtained by compounding a porous polyethylene film and a polypropylene film.

[0183] [Exterior body] In constructing a nonaqueous electrolyte secondary battery, the exterior body of the nonaqueous electrolyte secondary battery may 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, titanium, etc.

[0184] As the laminate exterior body, for example, an aluminum laminate film, a SUS laminate film, a silica-coated polypropylene, a polyethylene laminate film, or the like can be used.

[0185] 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 shape, a cylindrical shape, a square shape, or an aluminum laminate sheet shape is assembled from the above-mentioned elements. EXAMPLES

[0186] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0187] <About lithium-ion batteries> (Preparation of electrolyte) (Comparative electrolyte No.1-1) (III) A mixed solvent of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 2.5:4:3.5 was used as a nonaqueous organic solvent, and (IV) LiPF was added as a solute to the solvent. 6 (I) 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] as the first additive was dissolved in the nonaqueous organic solvent, the solute, and the compound at a concentration of 1.0 mass % (relative to the total amount of (I), (III), and (IV)) to obtain a comparative electrolyte No. 1-1 for nonaqueous electrolyte batteries. The preparation conditions for the comparative electrolyte No. 1-1 are shown in Table 1. In all tables hereafter, "-" indicates that no additive was added.

[0188] (Electrolyte No.1-1) (III) A mixed solvent of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 2.5:4:3.5 was used as a nonaqueous organic solvent, and (IV) LiPF was added as a solute to the solvent. 6(I) 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] as a first additive, and (II) a lithium salt of compound No. 2-1 represented by the above general formula [2] as a second additive were dissolved in a concentration of 1.0 mol / L relative to the total amount of (I) to (IV) of the nonaqueous electrolyte solution (relative to the total amount of (I) to (IV)) as shown in Table 1, to prepare electrolyte No. 1-1.

[0189] (Electrolyte No.1-2~No.1-27) (II) Electrolyte solutions No. 1-2 to No. 1-27 were prepared in the same manner as in electrolyte solution No. 1-1, except that, as the second additive, instead of the lithium salt of compound No. 2-1 represented by the above general formula [2], the compounds shown in Table 1 (the counter cations of the compounds of general formulas [2] to [4] are all lithium) were dissolved so as to have a concentration relative to the total amount of (I) to (IV) shown in Table 1. Incidentally, the electrolyte solutions 1-16 to 1-20 relating to the compound represented by the general formula [5] are reference examples.

[0190] (Comparative electrolyte No.1-2 ~No.1-28) Comparative electrolyte solutions No. 1-2 to No. 1-28 were prepared in the same manner as electrolyte solution No. 1-1, except that (I) no first additive was added, and (II) as the second additive, instead of the lithium salt of compound No. 2-1 represented by the above general formula [2], a compound shown in Table 2 (all of the counter cations of the compounds of general formulas [2] to [4] are lithium) was dissolved in the electrolyte solution in a concentration relative to the total amount of (I) to (IV) shown in Table 2.

[0191] [Table 1]

[0192] [Table 2]

[0193] (Electrolyte No.2-1) (III) A mixed solvent of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 2:4:4 was used as a nonaqueous organic solvent, and (IV) LiPF was added as a solute to the solvent. 6 (I) 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] as the first additive was dissolved in a concentration of 0.5 mass% relative to the total amount of (I) to (IV) relative to the total amount of the nonaqueous electrolyte (relative to the total amount of (I) to (IV)), and (II) lithium salt of compound No. 3-1 represented by the above general formula [3] as the second additive was dissolved in a concentration of 1.5 mass% relative to the total amount of (I) to (IV) to prepare electrolyte No. 2-1. The preparation conditions for electrolyte No. 2-1 are shown in Table 3.

[0194] (Electrolyte No.2-2~No.2-11) (I) As the first additive, instead of 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1], a and R b Electrolyte solutions No. 2-2 to No. 2-11 were prepared in the same manner as in electrolyte solution No. 2-1, except that a compound having the formula:

[0195] (Comparative electrolyte No.2-1 ~No.2-11) (II) No second additive is added, and (I) As the first additive, A and R shown in Table 3 are used instead of 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1]. a and R b Comparative electrolytes No. 2-1 to No. 2-11 were prepared in the same manner as electrolyte No. 2-1, except that a compound having the formula:

[0196] [Table 3]

[0197] (Electrolyte No.3-1) (III) A mixed solvent of propylene carbonate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 1:2:4:3 was used as a nonaqueous organic solvent, and (IV) LiPF was added as a solute to the solvent. 6 (I) 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] was dissolved as the first additive to a concentration of 0.05% by mass relative to the total amount of (I) to (IV) to a concentration of 1.0 mol / L relative to the total amount of the nonaqueous electrolyte (relative to the total amount of (I) to (IV)), and (II) lithium salt of compound No. 2-1 represented by the above general formula [2] was dissolved as the second additive to a concentration of 2.5% by mass relative to the total amount of (I) to (IV), and vinylene carbonate was dissolved as another additive or component to a concentration of 1.0% by mass relative to the total amount of the electrolyte to prepare electrolyte No. 3-1. The preparation conditions of electrolyte No. 3-1 are shown in Table 4.

[0198] (Electrolyte No.3-2~No.3-6) Electrolyte solutions No. 3-2 to No. 3-6 were prepared in the same manner as electrolyte solution No. 3-1, except that (I) 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] was dissolved as the first additive to a concentration shown in Table 4, and (II) lithium salt of compound No. 2-1 represented by the above general formula [2] was dissolved as the second additive to a concentration shown in Table 4.

[0199] (Electrolyte No.3-7~No.3-53) Electrolyte solutions No. 3-7 to No. 3-53 were prepared in the same manner as electrolyte solution No. 3-1, except that (I) as a first additive, 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] was dissolved to the concentrations shown in Tables 4 to 6, and (II) as a second additive, instead of the lithium salt of compound No. 2-1 represented by the above general formula [2], the compounds shown in Tables 4 to 6 (the counter cations of the compounds of general formulas [2] to [4] are all lithium) were dissolved to the concentrations shown in Tables 4 to 6, respectively.

[0200] (Comparative electrolyte No.3-1~No.3-9) Comparative electrolytes No. 3-1 to No. 3-9 were prepared in the same manner as electrolyte No. 3-1, except that (I) no first additive was added, and (II) the compounds shown in Tables 4 to 6 (the counter cations of the compounds of general formulas [2] to [4] are all lithium) were dissolved as the second additive to the concentrations shown in Tables 4 to 6, respectively.

[0201] (Comparative electrolyte No.3-10) (II) Comparative electrolyte No. 3-10 was prepared in the same manner as electrolyte No. 3-35, except that the second additive was not added.

[0202] [Table 4]

[0203] [Table 5]

[0204] [Table 6]

[0205] (Battery Construction) Using the above electrolyte, LiNi 0.6 Co 0.2 Mn 0.2 O 2The test cells were fabricated using the positive electrode material and graphite as the negative electrode material, and the high-temperature storage characteristics and low-temperature characteristics of the batteries were evaluated. The test cells were fabricated as follows. LiNi 0.6 Co 0.2 Mn 0.2 O 2 90% by mass of the powder was mixed with 5% by mass of polyvinylidene fluoride (hereinafter referred to as "PVDF") as a binder and 5% by mass of acetylene black as a conductive material, and N-methylpyrrolidone (hereinafter referred to as "NMP") was further added to make a paste. This paste was applied to aluminum foil and dried to make a test cathode body. In addition, 90% by mass of graphite powder was mixed with 10% by mass of PVDF as a binder, and NMP was further added to prepare a slurry. This slurry was applied onto copper foil and dried at 120° C. for 12 hours to prepare a test negative electrode body. Then, a polyethylene separator was impregnated with the electrolyte and a 50mAh cell with an aluminum laminate exterior was assembled.

[0206] [Low temperature output characteristic evaluation] Using the above cell, at an ambient temperature of 25°C, the upper limit of charging was 4.3 V and the lower limit of discharging was 3.0 V, using a constant current / constant voltage method with a current density of 0.33 mA / cm 2 The battery was charged and discharged 10 times at 1000 mA / cm. The 10th discharge capacity was designated as discharge capacity A. After this, the battery was charged to a maximum charge voltage of 4.3 V at a current density of 0.33 mA / cm using a constant current / constant voltage method at an ambient temperature of -15°C. 2 After charging with a current density of 9.5 mA / cm until the discharge cut-off voltage of 3.0 V 2 The discharge capacity at this time was designated as discharge capacity B, and the value calculated from "(discharge capacity B / discharge capacity A) x 100" was designated as the high output capacity maintenance rate (%), and the low temperature output characteristics of the cell were evaluated.

[0207] [Low temperature input characteristic evaluation] Using the above cell, at an ambient temperature of 25°C, the upper limit of charging was 4.3 V and the lower limit of discharging was 3.0 V, using a constant current / constant voltage method with a current density of 0.33 mA / cm 2The battery was charged and discharged 10 times at 1000 mA / cm. The 10th charge capacity was designated as charge capacity A. After this, the battery was charged at a constant current density of 9.0 mA / cm up to a maximum charge voltage of 4.3 V at an ambient temperature of -15°C. 2 The charge capacity at this time was designated as charge capacity B, and the value calculated from "(charge capacity B / charge capacity A) x 100" was designated as the high input capacity retention rate (%), and the low temperature input characteristics of the cell were evaluated.

[0208] [High temperature storage characteristic evaluation (durability at 80℃)] After the above charge and discharge, the current density was again 0.33 mA / cm 2 After charging to 4.3 V, the battery was stored at an ambient temperature of 80°C for 3 days. Then, the battery was charged at a current density of 0.33 mA / cm at an ambient temperature of 25°C. 2 The battery was discharged to 3.0 V, and then charged to an upper limit of 4.3 V using a constant current / constant voltage method at a current density of 0.33 mA / cm. 2 The battery was charged at a current density of 0.33 mA / cm until the final discharge voltage of 3.0 V. 2 The discharge capacities when the batteries were discharged at a constant current of 100 mA were compared and evaluated.

[0209] The results of nonaqueous electrolytes No. 1-1 to 1-15 and 1-21 to 1-27 and comparative nonaqueous electrolytes No. 1-1 to 1-16 and 1-22 to 1-28 were compared. More specifically, the results of the other Examples and Comparative Examples were expressed as relative values, with Comparative Example 1-1 using comparative nonaqueous electrolyte No. 1-1 being taken as the standard, the capacity retention rate in low-temperature output characteristics being 100, and the absolute value of the discharge capacity in high-temperature storage characteristics being 100. The results are shown in Tables 7 to 8.

[0210] Nonaqueous electrolyte No.1-16~1-20 (Reference example) The results of comparative nonaqueous electrolytes No. 1-17 to 1-21 were compared. More specifically, Comparative Example 1-1 using comparative nonaqueous electrolyte No. 1-1 was used as the standard, and the capacity retention rate in the low temperature input characteristics was set to 100, and the absolute value of the discharge capacity in the high temperature storage characteristics was set to 100, and the results of the other Examples and Comparative Examples were expressed as relative values. The results are shown in Table 9.

[0211] [Table 7]

[0212] [Table 8]

[0213] [Table 9]

[0214] As can be seen from Tables 7 to 9, (I) the comparative examples not containing the first additive (e.g., Comparative Example 1-2) are compared to the comparative examples not containing the first additive (I) the first additive represented by the above general formula [1] and (II) the general formula [2] to [4] A corresponding example (e.g., Example 1-1) containing at least one second additive selected from the group consisting of a compound represented by the formula (I), difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate showed results in which the low temperature characteristics and high temperature storage characteristics were further improved. In comparison with Examples 1-2 to 1-4, in Example 1-1, the low-temperature output characteristics and the high-temperature storage characteristics are further improved. 1 and R 2 However, it is particularly preferable that each of them is a fluorine atom.

[0215] Compared with Examples 1-6 to 1-8, Example 1-5 has a well-balanced improvement in low-temperature output characteristics and high-temperature storage characteristics. 3 ~R 6 However, it is particularly preferable that each of them is a fluorine atom.

[0216] In comparison with Examples 1-10 to 1-11 and 1-13 to 1-15, in Examples 1-9 and 1-12, the low-temperature output characteristics and the high-temperature storage characteristics are improved in a well-balanced manner. 7 ~R 9 are both fluorine atoms, or R 7 ~R8 are both fluorine atoms and R 9 It is particularly preferred that is a trifluoromethyl group.

[0217] In addition, reference Compared to examples 1-16 to 1-17 and 1-19 to 1-20, reference In Example 1-18, the low-temperature input characteristics and high-temperature storage characteristics are further improved. 10 is preferably a group selected from the group consisting of a vinyl group, an allyl group, a 1-propenyl group, a 2-propenyl group, an ethynyl group, and a 2-propynyl group, and is particularly preferably a vinyl group.

[0218] The results of the nonaqueous electrolyte solutions No. 2-1 to 2-11 and the comparative nonaqueous electrolyte solutions No. 2-1 to 2-11 were compared. More specifically, (II) the second additive is a compound represented by the above general formula [2] to [4] The results of each Example were expressed as a relative value, with each Comparative Example not containing at least one selected from the group consisting of the compound represented by the formula (I), difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate, and the absolute value of the capacity retention rate in the low-temperature output characteristic was set to 100, and the absolute value of the discharge capacity in the high-temperature storage characteristic was set to 100. The results are shown in Table 10.

[0219] [Table 10]

[0220] As can be seen from Table 10, (I) the first additive represented by the above general formula [1] and (II) the corresponding example (e.g., Example 2-1) containing the above second additive, compared to the corresponding comparative example (e.g., Comparative Example 2-1) not containing the second additive (II), showed improved low-temperature output characteristics and high-temperature storage characteristics.

[0221] The results of nonaqueous electrolytes No. 3-1 to 3-34 and comparative nonaqueous electrolytes No. 3-1 to 3-9 were compared. More specifically, the results of each Example were expressed as a relative value, with the capacity retention rate in the low-temperature output characteristics set to 100 and the absolute value of the discharge capacity in the high-temperature storage characteristics set to 100, for each Comparative Example in which the first additive (I) was not added. The results are shown in Tables 11 and 12.

[0222] The results of nonaqueous electrolytes No. 3-35 to 3-53 and comparative nonaqueous electrolyte No. 3-10 were compared. More specifically, the results of each Example were expressed as a relative value, with Comparative Example 3-10, in which no (II) second additive was added, being taken as the standard, the capacity retention rate in the low-temperature output characteristics being 100, and the absolute value of the discharge capacity in the high-temperature storage characteristics being 100. The results are shown in Table 13.

[0223] [Table 11]

[0224] [Table 12]

[0225] [Table 13]

[0226] As can be seen from Tables 11 and 12, (I) the comparative example not containing the first additive (e.g., Comparative Example 3-1) was compared to the comparative example not containing the first additive (e.g., Comparative Example 3-2), which contained the first additive represented by the above general formula [1] and the second additive represented by the above general formula [2] to [4] A corresponding example (e.g., Example 3-1) including at least one selected from the group consisting of a compound represented by the formula (I), difluoro(oxalato)borate, bis(oxalato)borate, tetrafluoro(oxalato)phosphate, difluorobis(oxalato)phosphate, tris(oxalato)phosphate, difluorophosphate, and fluorosulfonate showed results in which the low-temperature output characteristics and high-temperature storage characteristics were further improved. That is, the content of the first additive (I) relative to the total amount of (I) to (IV) is preferably 0.01 to 10.0 mass %, and more preferably 0.05 to 5.0 mass %.

[0227] Compared with Examples 3-1 to 3-2 and 3-6, Examples 3-3 to 3-5 have improved low-temperature output characteristics and high-temperature storage characteristics. Therefore, the content of (I) above with respect to the total amount of (I) to (IV) above is preferably 0.5 to 2.0 mass%.

[0228] As can be seen from Table 13, compared to the comparative examples (e.g., Comparative Example 3-10) that do not contain the second additive (II), the examples (e.g., Example 3-35) that contain the first additive represented by the general formula [1] above and the second additive (II) above showed improved low-temperature output characteristics and high-temperature storage characteristics. That is, the content of (II) relative to the total amount of (I) to (IV) is preferably 0.005 to 12.0 mass%, more preferably 0.05 to 10.0 mass%, and particularly preferably 0.1 to 5.0 mass%.

[0229] <About sodium-ion batteries> (Preparation of electrolyte) (Comparative electrolyte No.4-1) (III) As a non-aqueous organic solvent, a mixed solvent of propylene carbonate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 2:1:4:3 was used, and (IV) NaPF was added as a solute to the solvent. 6 (I) 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] as the first additive was dissolved in the nonaqueous solvent, the solute, and the compound at a concentration of 1.0 mass% (relative to the total amount of (I), (III), and (IV)) to obtain a comparative electrolyte No. 4-1 for nonaqueous electrolyte batteries. The preparation conditions for comparative electrolyte No. 4-1 are shown in Table 14.

[0230] (Electrolyte No.4-1) (III) As a non-aqueous organic solvent, a mixed solvent of propylene carbonate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 2:1:4:3 was used, and (IV) NaPF was added as a solute to the solvent. 6 (I) 3-(difluorophosphinyloxy)tetrahydrothiophene-1,1-dioxide represented by the above general formula [1] as a first additive, and (II) the sodium salt of compound No. 2-1 represented by the above general formula [2] as a second additive were dissolved in the above-mentioned electrolyte solution No. 4-1 at a concentration of 1.15 mol / L relative to the total amount of (I) to (IV) shown in Table 14.

[0231] (Electrolyte No.4-2 ~No.4-25) (II) Electrolyte solutions No. 4-2 to No. 4-25 were prepared in the same manner as electrolyte solution No. 4-1, except that, as a second additive, instead of the sodium salt of compound No. 2-1 represented by the above general formula [2], the compounds shown in Table 14 (the counter cations of the compounds of general formulas [2] to [4] are all sodium) were dissolved therein to the concentrations relative to the total amounts of (I) to (IV) shown in Table 14.

[0232] (Comparative electrolyte No.4-2 ~No.4-26) Comparative electrolytes No. 4-2 to No. 4-26 were prepared in the same manner as electrolyte No. 4-1, except that (I) no first additive was added, and (II) as the second additive, instead of the sodium salt of compound No. 2-1 represented by the above general formula [2], a compound shown in Table 15 (the counter cations of the compounds of general formulas [2] to [4] are all sodium) was dissolved to the concentrations shown in Table 15. It should be noted that electrolyte solutions Nos. 4-14 to 4-18, which contain the silicon compound represented by formula [5], are for reference only.

[0233] [Table 14]

[0234] [Table 15]

[0235] (Battery Construction) Using the above electrolyte, NaNi 0.5 Ti 0.3 Mn 0.2 O 2 As the positive electrode material, and as the negative electrode material, a cell was fabricated, and the high-temperature storage characteristics and low-temperature characteristics of the battery were evaluated. The test cell was fabricated as follows. NaNi 0.5 Ti 0.3 Mn 0.2 O 2 90% by mass of the powder was mixed with 5% by mass of PVDF as a positive electrode binder and 5% by mass of acetylene black as a conductive material, and NMP was further added to make a paste. This paste was applied to an aluminum foil and dried to prepare a test positive electrode body. In addition, 90% by mass of hard carbon powder was mixed with 10% by mass of PVDF as a negative electrode binder, and NMP was further added to prepare a slurry. The slurry was applied onto an aluminum foil and dried to prepare a test negative electrode body. Then, a polyethylene separator was impregnated with the electrolyte and a 50mAh cell with an aluminum laminate exterior was assembled.

[0236] [Low temperature output characteristic evaluation] Using the above cell, at an ambient temperature of 25°C, the upper limit of charging was 4.1V and the lower limit of discharging was 1.5V, using a constant current / constant voltage method with a current density of 0.33mA / cm 2 The battery was charged and discharged 10 times at 1000 mA / cm. The 10th discharge capacity was designated as discharge capacity A. After this, the battery was charged at a current density of 0.33 mA / cm using a constant current / constant voltage method up to a maximum charging voltage of 4.1 V at an ambient temperature of -15°C. 2 After charging with a current density of 9.5 mA / cm until the discharge cut-off voltage of 1.5 V 2The discharge capacity at this time was designated as discharge capacity B, and the value calculated from "(discharge capacity B / discharge capacity A) x 100" was designated as the high output capacity maintenance rate (%), and the low temperature output characteristics of the cell were evaluated.

[0237] [Low temperature input characteristic evaluation] Using the above cell, at an ambient temperature of 25°C, the upper limit of charging was 4.1V and the lower limit of discharging was 1.5V, using a constant current / constant voltage method with a current density of 0.33mA / cm 2 The battery was charged and discharged 10 times at 1000 mA / cm. The 10th charge capacity was designated as charge capacity A. After this, the battery was charged at a constant current density of 9.0 mA / cm up to a maximum charge voltage of 4.1 V at an ambient temperature of -15°C. 2 The charge capacity at this time was designated as charge capacity B, and the value calculated from "(charge capacity B / charge capacity A) x 100" was designated as the high input capacity retention rate (%), and the low temperature input characteristics of the cell were evaluated.

[0238] [High temperature storage characteristic evaluation (durability at 80℃)] After the above charge and discharge, the current density was again 0.33 mA / cm 2 After charging to 4.1 V, the battery was stored at an ambient temperature of 80°C for 3 days. Then, the battery was charged at a current density of 0.33 mA / cm at an ambient temperature of 25°C. 2 The battery was discharged to 1.5 V, and then charged to an upper limit of 4.1 V at a current density of 0.33 mA / cm using a constant current / constant voltage method. 2 The battery was charged at a current density of 0.33 mA / cm until the discharge cut-off voltage of 1.5 V. 2 The discharge capacities when the batteries were discharged at a constant current of 100 mA were compared and evaluated.

[0239] The results of nonaqueous electrolytes No. 4-1 to 4-13 and 4-19 to 4-25 and comparative nonaqueous electrolytes No. 4-1 to 4-14 and 4-20 to 4-26 were compared. More specifically, the results of the other Examples and Comparative Examples were expressed as relative values, with Comparative Example 4-1 using comparative nonaqueous electrolyte No. 4-1 as the standard, the capacity retention rate in the low-temperature output characteristics as 100, and the absolute value of the discharge capacity in the high-temperature storage characteristics as 100. The results are shown in Tables 16 to 17.

[0240] The results of nonaqueous electrolyte Nos. 4-14 to 4-18 and comparative nonaqueous electrolyte Nos. 4-15 to 4-19 were compared. More specifically, the results of each of the other Examples and Comparative Examples were expressed as relative values, with Comparative Example 4-1 using comparative nonaqueous electrolyte No. 4-1 as the standard, the capacity retention rate in the low temperature input characteristic being set to 100, and the absolute value of the discharge capacity in the high temperature storage characteristic being set to 100. The results are shown in Table 18.

[0241] [Table 16]

[0242] [Table 17]

[0243] [Table 18]

[0244] Table 16~ 17 As can be seen from the results, the corresponding examples (e.g., Example 4-1) containing the first additive (I) and the second additive (II) showed improved low temperature properties and high temperature storage properties compared to the corresponding comparative examples (e.g., Comparative Example 4-2) not containing the first additive (I) or the corresponding comparative example 4-1 not containing the second additive (II).

[0245] Compared with Examples 4-2 to 4-4, Example 4-1 has a well-balanced improvement in low-temperature output characteristics and high-temperature storage characteristics. 1 and R 2 However, it is particularly preferable that each of them is a fluorine atom.

[0246] Compared with Example 4-6, Example 4-5 has a well-balanced improvement in low-temperature output characteristics and high-temperature storage characteristics. 3 ~R 6 However, it is particularly preferable that each of them is a fluorine atom.

[0247] In comparison with Examples 4-8 to 4-9 and 4-11 to 4-13, Examples 4-7 and 4-10 have improved low-temperature output characteristics and high-temperature storage characteristics. 7 ~R 9 are both fluorine atoms, or R 7 ~R 8 are both fluorine atoms and R 9 It is particularly preferred that is a trifluoromethyl group.

[0248] For reference, Compared to Examples 4-14 to 4-15 and 4-17 to 4-18, reference In Example 4-16, the low-temperature input characteristics and high-temperature storage characteristics are further improved. 10 is preferably a group selected from the group consisting of a vinyl group, an allyl group, a 1-propenyl group, a 2-propenyl group, an ethynyl group, and a 2-propynyl group, and is particularly preferably a vinyl group.

Claims

1. (I) a first additive represented by the following general formula [1]: (II) at least one second additive selected from the group consisting of compounds represented by the following general formulas [2] to [4], lithium or sodium difluoro(oxalato)borate, lithium or sodium bis(oxalato)borate, lithium or sodium tetrafluoro(oxalato)phosphate, lithium or sodium difluorobis(oxalato)phosphate, lithium or sodium tris(oxalato)phosphate, lithium or sodium difluorophosphate, and lithium or sodium fluorosulfonate; (III) a nonaqueous organic solvent, and (IV) solute, A non-aqueous electrolyte comprising: 【Chemistry 1】 [In 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. 【Chemistry 2】 [In formula [2], R 1 and R 2 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, in which a fluorine atom, an oxygen atom, or an unsaturated bond may be present in the organic group, with the proviso that R 1 and R 2 At least one of is a fluorine atom, M m+ is a lithium ion or a sodium ion, and m represents an integer equal to the valence of the corresponding cation. 【Chemistry 3】 [In formula [3], R 3 ~R 6 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, in which a fluorine atom, an oxygen atom, a cyano group, or an unsaturated bond may be present in the organic group, with the proviso that R 3 ~R 6 is a fluorine atom, and M m+ , m is the same as in general formula [2]. 【Chemistry 4】 [In 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, in which a fluorine atom, an oxygen atom, or an unsaturated bond may be present in the organic group, with the proviso that R 7 ~R 9 is a fluorine atom, and M m+ , m is the same as in general formula [2]. However, the non-aqueous electrolyte does not contain a silicon compound represented by the following formula A. [C5] Si(R 1 ) a (R 2 ) 4-a (Formula A) [In general formula (A), R 1 s each independently represent a group having a carbon-carbon unsaturated bond. R 2 s each independently represent a group selected from the group consisting of a fluorine atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an allyl group having 3 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, an allyloxy group having 3 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, and an aryloxy group having 6 to 15 carbon atoms, and these groups may have a fluorine atom and / or an oxygen atom. a is 2 to 4.]

2. In the general formula [1], R a and R b are each independently a fluorine atom, an alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom, an alkenyloxy group having 2 to 4 carbon atoms which may be substituted with a halogen atom, an alkynyloxy group having 2 to 4 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.

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

4. The second additive comprises a compound represented by the general formula [2], wherein R 1 and R 2 The nonaqueous electrolyte solution according to any one of claims 1 to 3, wherein each of is a fluorine atom.

5. The second additive comprises a compound represented by the general formula [2], R 1 is a fluorine atom, R 2 is an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, or an alkynyloxy group having 6 or less carbon atoms, which may contain a fluorine atom.

6. The second additive comprises a compound represented by the general formula [2], R 1 is a fluorine atom, R 2 is a group selected from a methyl group, a methoxy group, an ethyl group, an ethoxy group, an n-propyl group, an n-propoxy group, an isopropyl group, an isopropoxy group, a vinyl group, an allyl group, an allyloxy group, an ethynyl group, a 2-propynyl group, a 2-propynyloxy group, a phenyl group, a phenyloxy group, a trifluoromethyl group, a trifluoromethoxy group, a 2,2-difluoroethyl group, a 2,2-difluoroethyloxy group, a 2,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyloxy group, a 2,2,3,3-tetrafluoropropyl group, a 2,2,3,3-tetrafluoropropyloxy group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyloxy group. The nonaqueous electrolyte solution according to any one of claims 1 to 3 and 5.

7. The second additive comprises a compound represented by the general formula [3], wherein R 3 ~R 6 The nonaqueous electrolyte solution according to any one of claims 1 to 3, wherein each of is a fluorine atom.

8. The second additive comprises a compound represented by the general formula [3], R 3 ~R 6 At least one of the following is a fluorine atom: R 3 ~R 6 The nonaqueous electrolyte solution according to any one of claims 1 to 3, wherein at least one of the groups is selected from an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, and an alkynyloxy group, each of which has 6 or less carbon atoms and may contain a fluorine atom.

9. The second additive comprises a compound represented by the general formula [3], R 3 ~R 6 At least one of the following is a fluorine atom: R 3 ~R 6 At least one of the above is selected from the group consisting of a methyl group, a methoxy group, an ethyl group, an ethoxy group, an n-propyl group, an n-propoxy group, an isopropyl group, an isopropoxy group, a vinyl group, an allyl group, an allyloxy group, an ethynyl group, a 2-propynyl group, a 2-propynyloxy group, a phenyl group, a phenyloxy group, a trifluoromethyl group, a trifluoromethoxy group, a 2,2-difluoroethyl group, a 2,2-difluoroethyloxy group, a 2,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyloxy group, a 2,2,3,3-tetrafluoropropyl group, a 2,2,3,3-tetrafluoropropyloxy group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyloxy group. The nonaqueous electrolyte solution according to any one of claims 1 to 3 and 8.

10. The second additive comprises a compound represented by the general formula [4], wherein R 7 ~R 9 The nonaqueous electrolyte solution according to any one of claims 1 to 3, wherein each of is a fluorine atom.

11. The second additive comprises a compound represented by the general formula [4], wherein the general formula [4] is R 7 ~R 9 At least one of the following is a fluorine atom: R 7 ~R 9 The nonaqueous electrolyte solution according to any one of claims 1 to 3, wherein at least one of the groups is selected from an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, and an alkynyloxy group, each of which has 6 or less carbon atoms and may contain a fluorine atom.

12. The second additive comprises a compound represented by the general formula [4], R 7 ~R 9 At least one of the following is a fluorine atom: R 7 ~R 9 At least one of the above is selected from the group consisting of a methyl group, a methoxy group, an ethyl group, an ethoxy group, an n-propyl group, an n-propoxy group, an isopropyl group, an isopropoxy group, a vinyl group, an allyl group, an allyloxy group, an ethynyl group, a 2-propynyl group, a 2-propynyloxy group, a phenyl group, a phenyloxy group, a trifluoromethyl group, a trifluoromethoxy group, a 2,2-difluoroethyl group, a 2,2-difluoroethyloxy group, a 2,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyloxy group, a 2,2,3,3-tetrafluoropropyl group, a 2,2,3,3-tetrafluoropropyloxy group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyloxy group. The nonaqueous electrolyte solution according to any one of claims 1 to 3 and 11.

13. The nonaqueous electrolyte solution according to any one of claims 1 to 12, wherein the second additive comprises any one of the compounds represented by the general formulas [2] to [4].

14. The nonaqueous electrolyte solution according to any one of claims 1 to 13, wherein the content of (I) is 0.01 to 10.0 mass% based on the total amount of (I) to (IV).

15. The nonaqueous electrolyte solution according to any one of claims 1 to 14, wherein the content of (II) is 0.005 to 12.0 mass% relative to the total amount of (I) to (IV).

16. The (IV) 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, LiI, NaPF 6 , NaBF 4 , NaSbF 6 , NaAsF 6 , NaClO 4 , NaCF 3 SO 3 , NaC 4 F 9 SO 3 , NaAlO 2 , NaAlCl 4 15. The non-aqueous electrolyte solution according to claim 1, which is at least one selected from the group consisting of NaCl, and NaI.

17. The nonaqueous electrolyte solution according to any one of claims 1 to 16, wherein the (III) is at least one selected from the group consisting of cyclic carbonates, chain carbonates, cyclic esters, chain esters, cyclic ethers, chain ethers, sulfone compounds, sulfoxide compounds, and ionic liquids.

18. Further, vinylene carbonate, vinylene carbonate oligomer (having a number average molecular weight of 170 to 5000 in terms of polystyrene), vinyl ethylene carbonate, fluoroethylene carbonate, 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-ethane disulfonic anhydride, methanesulfonyl The non-aqueous electrolyte solution according to any one of claims 1 to 17, comprising at least one additive selected from the group consisting of tetrafluoroethylene, tris(trimethylsilyl)borate, succinonitrile, (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.

19. A non-aqueous electrolyte secondary battery comprising at least a positive electrode, a negative electrode, and the non-aqueous electrolyte according to any one of claims 1 to 18.

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