Electrolyte, electrochemical device, lithium ion secondary battery, and assembly

Abstract

The present application provides an electrolyte capable of improving the high-temperature storage characteristics and cycle characteristics of an electrochemical device. The electrolyte contains at least one compound represented by General Formula (1-1) (in the formula, R 101 is an alkyl group having 1 to 7 carbon atoms which can be fluorinated, etc., and can also contain O, etc. in the structure) and General Formula (1-2) (in the formula, R 102 and R 103 (i) are independently H, F, an alkyl group having 1 to 7 carbon atoms which can be fluorinated, etc., or (ii) are a hydrocarbon group which is linked to each other to form a 5- or 6-membered heterocycle together with the nitrogen atom, and can also contain O, etc. in the structure).

Description

[0001] This application is a divisional application of Chinese invention patent application No. 201980007334.2, filed on January 9, 2019, entitled "Electrolyte, Electrochemical Device, Lithium-ion Secondary Battery and Components". Technical Field

[0002] This invention relates to electrolytes, electrochemical devices, lithium-ion secondary batteries and components. Background Technology

[0003] With the recent trend towards lighter and smaller electrical products, the development of electrochemical devices such as high-energy-density lithium-ion secondary batteries is underway. Furthermore, as the application areas of these devices expand, improvements in their performance are required. This is particularly true in the future use of lithium-ion secondary batteries in automotive applications, where improved battery performance will become increasingly important.

[0004] Patent document 1 describes an electrolyte containing compounds such as methyl acrylate.

[0005] Patent document 2 describes an electrolyte containing compounds such as N,N-dimethylacrylamide.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2001-185212

[0009] Patent Document 2: Japanese Patent Application Publication No. 2003-86246 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] The purpose of this invention is to provide an electrolyte that can improve the high-temperature storage and cycling characteristics of electrochemical devices, and an electrochemical device having the electrolyte.

[0012] Another objective of this invention is to provide novel fluoroacrylate compounds and fluoroacrylamide compounds.

[0013] Means for solving technical problems

[0014] The present invention relates to an electrolyte, characterized in that it contains at least one compound selected from those represented by the following general formulas (1-1) and (1-2).

[0015] General formula (1-1):

[0016]

Chemistry 1

[0017]

[0018] (where R is in the formula) 101 It can be an alkyl group with 1 to 7 carbon atoms that can be fluorinated, an alkenyl group with 2 to 8 carbon atoms that can be fluorinated, an alkynyl group with 2 to 9 carbon atoms that can be fluorinated, or an aryl group with 6 to 12 carbon atoms that can be fluorinated, and may contain at least one selected from O, Si, S and N in its structure.

[0019] General formula (1-2):

[0020]

Chemistry 2

[0021]

[0022] (where R is in the formula) 102 and R 103 (i) independently of H, F, an alkyl group having 1 to 7 carbon atoms that can be fluorinated, an alkenyl group having 2 to 7 carbon atoms that can be fluorinated, an alkynyl group having 2 to 9 carbon atoms that can be fluorinated, or an aryl group having 5 to 12 carbon atoms that can be fluorinated, or (ii) a hydrocarbon group that is linked together with a nitrogen atom to form a 5- or 6-membered heterocycle. R 102 and R 103 The structure may contain at least one of O, S, and N.

[0023] The present invention also relates to an electrochemical device, characterized in that it comprises the above-mentioned electrolyte.

[0024] The present invention also relates to a lithium-ion secondary battery, characterized in that it comprises the above-mentioned electrolyte.

[0025] The present invention also relates to a component characterized by having the above-described electrochemical device or the above-described lithium-ion secondary battery.

[0026] This invention relates to a compound characterized by being represented by the following general formula (11):

[0027]

Transformation 3

[0028]

[0029] (where R is in the formula) 111 It can be a fluoroalkenyl group with 2 to 7 carbon atoms, a fluoroalkynyl group with 2 to 7 carbon atoms, an unfluorinated alkynyl group with 5 to 9 carbon atoms, or an aryl group with 6 to 12 carbon atoms that can be fluorinated. The structure may also contain at least one group selected from O and Si.

[0030] This invention relates to a compound characterized by being represented by the following general formula (12):

[0031]

Chemistry 4

[0032]

[0033] (where R is in the formula) 112 and R 113 (i) Independently comprising F, an unfluorinated alkyl group having 1 to 7 carbon atoms, a fluorinated alkyl group having 1 to 5 carbon atoms, an alkenyl group having 3 to 7 carbon atoms that can be fluorinated, or an alkynyl group having 3 to 7 carbon atoms that can be fluorinated, and R 112 and R 113 At least one of them is F, an unfluorinated alkyl group having 3 to 7 carbon atoms, a fluorinated alkyl group having 1 to 5 carbon atoms, an alkenyl group having 3 to 7 carbon atoms that can be fluorinated, or an alkynyl group having 3 to 7 carbon atoms that can be fluorinated, or (ii) a hydrocarbon group that is linked together with a nitrogen atom to form a 5- or 6-membered heterocycle. R 112 and R 113 The structure may contain at least one of O, S, and N.

[0034] Invention Effects

[0035] The electrolyte according to the present invention can improve the high-temperature storage characteristics and cycling characteristics of electrochemical devices. Electrochemical devices equipped with the above-described electrolyte exhibit excellent high-temperature storage characteristics and cycling characteristics.

[0036] In addition, according to the present invention, novel fluoroacrylate compounds and fluoroacrylamide compounds can be provided. Detailed Implementation

[0037] The present invention will now be described in detail.

[0038] The electrolyte of the present invention is characterized in that it contains at least one of the compounds selected from those represented by the following general formulas (1-1) and (1-2) (hereinafter also referred to as compound (1)).

[0039] General formula (1-1):

[0040]

Transformation 5

[0041]

[0042] General formula (1-2):

[0043]

Transformation 6

[0044]

[0045] Through the above features, the electrolyte of the present invention can improve the high-temperature storage characteristics and cycle characteristics of electrochemical devices.

[0046] In addition, in the past, electrolytes containing various additives have been proposed to improve the characteristics of non-aqueous electrolyte secondary batteries. Examples of such additives include vinylene carbonate and its derivatives (Japanese Patent Application Publication No. 8-45545) and halogen-substituted cyclic carbonates (International Publication No. 98 / 15024). However, in electrolytes containing these compounds, the compounds are reduced and decomposed on the negative electrode surface to form a coating. This coating can suppress excessive decomposition of the electrolyte and improve charge-discharge cycle performance. On the other hand, there is a problem of high gas generation when storing secondary batteries at high temperatures and high voltages, and during repeated charge-discharge cycles. The electrolyte of the present invention, by containing compound (1), can suppress the amount of gas generated during high-temperature storage and charge-discharge cycles, thereby improving battery characteristics.

[0047] Compound (1) is selected from at least one compound represented by general formula (1-1) and compound (1-2) represented by general formula (1-2).

[0048] In general formula (1-1), R 101 It may be an alkyl group having 1 to 7 carbon atoms that can be fluorinated, an alkenyl group having 2 to 8 carbon atoms that can be fluorinated, an alkynyl group having 2 to 9 carbon atoms that can be fluorinated, or an aryl group having 6 to 12 carbon atoms that can be fluorinated, and may contain at least one selected from O, Si, S and N in its structure.

[0049] As R 101 The number of carbon atoms in the alkyl group is preferably 1 to 5, more preferably 1 to 4.

[0050] The alkyl group described above can be an unfluorinated alkyl group or a fluorinated alkyl group. Additionally, it may contain at least one element selected from O, Si, S, and N. Furthermore, the alkyl group may have a cyclic structure. The cyclic structure may be an aromatic ring.

[0051] As R 101Examples of the aforementioned alkyl groups include unfluorinated alkyl groups such as methyl (-CH3), ethyl (-CH2CH3), propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), and n-butyl (-CH2CH2CH2CH3); and -CF3, -CF2H, -CFH2, -CF2CF3, -CF2CF2H, -CF2CFH2, -CH2CF3, -CH2CF2H, -CH2CFH2, -CF2CF2CF3, -CF2CF2CF2H, -CF2CF2CFH2, and -CH2CF2C. Fluoroalkyl groups such as F3, -CH2CF2CF2H, -CH2CF2CFH2, -CH2CH2CF3, -CH2CH2CF2H, -CH2CH2CFH2, -CF(CF3)2, -CF(CF2H)2, -CF(CFH2)2, -CH(CF3)2, -CH(CF2H)2, -CH(CFH2)2, -CH2CF(CF3)OC3F7, -CH2CF2OCF3; and trialkylsilyl alkyl groups such as -CH2Si(CH3)3 or -CH2CH2Si(CH3)3.

[0052] In addition, examples can be given of cycloalkyl groups or alkyl groups having aromatic rings, which may contain at least one of O, Si, S and N in their structure, as shown in the following formula.

[0053]

Transformation 7

[0054]

[0055] As the above-mentioned alkyl group, methyl, ethyl, -CH2CF3, -CH2CF2H, -CH2CFH2, -CH2CF2CF3, -CH2CF2CF2H, -CH2CF2CFH2, and -CH2Si(CH3)3 are preferred.

[0056] As R 101 The number of carbon atoms in the alkenyl group is preferably 2 to 6, more preferably 2 to 5.

[0057] The alkenyl group mentioned above can be an unfluorinated alkenyl group or a fluorinated alkenyl group. In addition, the structure may contain at least one of O, Si, S and N.

[0058] As R 101Examples of the alkenyl groups mentioned above include vinyl (-CH=CH2), 1-propenyl (-CH=CH-CH3), 1-methyl vinyl (-C(CH3)=CH2), 2-propenyl (-CH2-CH=CH2), 1-butenyl (-CH=CH-CH2CH3), 2-methyl-1-propenyl (-CH=C(CH3)-CH3), 1-methyl-1-propenyl (-C(CH3)=CH-CH3), 1-ethyl vinyl (-C(CH2CH3)=CH2), 2-butenyl (-CH2-CH=CH-CH3), 2-methyl-2-propenyl (-CH2-C(CH3)=CH2), 1-methyl-2-propenyl (-CH(CH3)-CH=CH2), and 3-butenyl (-CH2CH2-CH =CH2), 1-methylene-2-propenyl (-C(=CH2)-CH=CH2), 1,3-butadienyl (-CH=CH-CH=CH2), 2,3-butadienyl (-CH2-CH=C=CH2), 1-methyl-1,2-propadienyl (-C(CH3)=C=CH2), 1,2-butadienyl (-CH=C=CH-CH3), 2-pentenyl (-CH2-CH=CH-CH2CH3), 2-ethyl-2-propenyl (-CH2-C(CH2CH3)=CH2), 1-ethyl-2-propenyl (-CH(CH2CH3)-CH=CH2), 3-pentenyl (-CH2CH2-CH=CH-CH3), and groups formed by replacing at least one hydrogen atom of these groups with a fluorine atom.

[0059] In addition, examples include cycloalkenyl groups represented by the following formulas, and groups in which at least one hydrogen atom is replaced by a fluorine atom.

[0060]

Transformation 8

[0061]

[0062] As the alkenyl group mentioned above, 2-propenyl (-CH2-CH=CH2), 3-butenyl (-CH2CH2-CH=CH2), 2-butenyl (-CH2-CH=CH-CH3), 2-methyl-2-propenyl (-CH2-C(CH3)=CH2), and 2-pentenyl (-CH2-CH=CH-CH2CH3) are preferred.

[0063]

Chemistry 9

[0064]

[0065] And groups in which at least one hydrogen atom is replaced by a fluorine atom, more preferably 2-propenyl (-CH2-CH=CH2), 2-butenyl (-CH2-CH=CH-CH3), 2-pentenyl (-CH2-CH=CH-CH2CH3),

[0066]

Chemistry 10

[0067]

[0068] And groups formed by replacing at least one hydrogen atom with a fluorine atom in these groups.

[0069] As R 101 The number of carbon atoms in the above-mentioned alkynyl group is preferably 3 to 9, more preferably 3 to 4 or 6 to 9.

[0070] The aforementioned alkynyl group can be an unfluorinated alkynyl group or a fluorinated alkynyl group. In addition, the structure may contain at least one of O, Si, S and N.

[0071] As R 101 Examples of the aforementioned alkynyl groups include ethynyl (-C≡CH), 1-propynyl (-C≡C-CH3), 2-propynyl (-CH2-C≡CH), 1-butynyl (-C≡C-CH2CH3), 2-butynyl (-CH2-C≡C-CH3), 3-butynyl (-CH2CH2-C≡CH), 1-pentynyl (-C≡C-CH2CH2CH3), and 2-pentynyl (-CH2-C≡C-CH2CH3). ), 3-pentynyl (-CH2CH2-C≡C-CH3), 4-pentynyl (-CH2CH2CH2-C≡CH), -CH2-C≡C-TMS, -CH2-C≡C-TES, -CH2-C≡C-TBDMS, -CH2-C≡C-Si(OCH3)3, -CH2-C≡C-Si(OC2H5)3, and groups in which at least one hydrogen atom is replaced by a fluorine atom, etc.

[0072] Additionally, TMS stands for -Si(CH3)3, TES stands for -Si(C2H5)3, and TBDMS stands for -Si(CH3)2C(CH3)3.

[0073] As the aforementioned alkynyl group, 2-propynyl (-CH2-C≡CH), 2-butynyl (-CH2-C≡C-CH3), -CH2-C≡C-TMS, -CH2-C≡C-TBDMS, and groups in which at least one hydrogen atom is replaced by a fluorine atom are preferred, and 2-propynyl (-CH2-C≡CH), -CH2-C≡CF, -CH2-C≡C-CF3, -CH2-C≡C-TMS, and -CH2-C≡C-TBDMS are more preferred.

[0074] As R 101 The aryl group mentioned above is a group formed by removing one hydrogen atom from an aromatic ring, preferably containing a 6-membered aromatic hydrocarbon ring, and preferably a monocyclic or bicyclic type.

[0075] The aryl group mentioned above can be an unfluorinated aryl group or a fluorinated aryl group. In addition, the structure may contain at least one of O, Si, S and N.

[0076] Examples of aryl groups include phenyl, tolyl, xylyl, methoxybenzyl, and naphthyl, which may or may not have fluorine atoms. Among these, phenyl groups that may have fluorine atoms are preferred, and phenyl groups that do not have fluorine atoms are more preferred.

[0077] As R 101 Preferably, it is an alkenyl group that can be fluorinated or an alkynyl group that can be fluorinated.

[0078] As a compound (1-1), for example, compounds represented by the following formula can be exemplified.

[0079]

Chemistry 11

[0080]

[0081]

Chemistry 12

[0082]

[0083]

Chemistry 13

[0084]

[0085] As compound (1-1), preferably a compound represented by the following formula.

[0086]

Chemistry 14

[0087]

[0088]

Chemistry 15

[0089]

[0090] As compound (1-1), the compound represented by the following formula is particularly preferred.

[0091]

Chemistry 16

[0092]

[0093] Among compounds (1-1), compound (11) characterized by the following general formula (11) is a novel compound. The present invention also relates to compound (11).

[0094]

Chemistry 17

[0095]

[0096] In general formula (11), R 111 It can be a fluoroalkenyl group with 2 to 7 carbon atoms, a fluoroalkynyl group with 2 to 7 carbon atoms, an unfluorinated alkynyl group with 5 to 9 carbon atoms, or an aryl group with 6 to 12 carbon atoms that can be fluorinated, and may also contain at least one of O and Si in its structure.

[0097] As R 111 The number of carbon atoms in the fluorinated alkenyl group is preferably 2 to 6, more preferably 2 to 5.

[0098] The aforementioned fluorinated alkenyl groups may contain at least one selected from O and Si in their structure.

[0099] As R 111Examples of the aforementioned fluorinated alkenyl groups include those formed by replacing at least one hydrogen atom with a fluorine atom in the following groups: vinyl (-CH=CH2), 1-propenyl (-CH=CH-CH3), 1-methyl vinyl (-C(CH3)=CH2), 2-propenyl (-CH2-CH=CH2), 1-butenyl (-CH=CH-CH2CH3), 2-methyl-1-propenyl (-CH=C(CH3)-CH3), 1-methyl-1-propenyl (-C(CH3)=CH-CH3), 1-ethyl vinyl (-C(CH2CH3)=CH2), 2-butenyl (-CH2-CH=CH-CH3), 2-methyl-2-propenyl (-CH2-C(CH3)=CH2), 1-methyl-2-propenyl (-CH(CH2)=CH2), and 1-methyl-2-propenyl (-CH(CH2)=CH2). 3) -CH=CH2), 3-butenyl (-CH2CH2-CH=CH2), 1-methylene-2-propenyl (-C(=CH2)-CH=CH2), 1,3-butadienyl (-CH=CH-CH=CH2), 2,3-butadienyl (-CH2-CH=C=CH2), 1-methyl-1,2-propadienyl (-C(CH3)=C=CH2), 1,2-butadienyl (-CH=C=CH-CH3), 2-pentenyl (-CH2-CH=CH-CH2CH3), 2-ethyl-2-propenyl (-CH2-C(CH2CH3)=CH2), 1-ethyl-2-propenyl (-CH(CH2CH3)-CH=CH2) and 3-pentenyl (-CH2CH2-CH=CH-CH3).

[0100] As the above-mentioned fluorinated alkenyl group, preferably 2-propenyl (-CH2-CH=CH2), 2-butenyl (-CH2-CH=CH-CH3) and 2-pentenyl (-CH2-CH=CH-CH2CH3) are groups in which at least one hydrogen atom is replaced by a fluorine atom.

[0101] As R 111 The number of carbon atoms in the above-mentioned fluoroalkynyl group is preferably 2 to 6, more preferably 3 to 5.

[0102] The aforementioned fluoroalkynyl group may contain at least one selected from O and Si in its structure.

[0103] As R 111Examples of the aforementioned fluoroalkynyl groups include those formed by replacing at least one hydrogen atom with a fluorine atom in the following groups: ethynyl (-C≡CH), 1-propynyl (-C≡C-CH3), 2-propynyl (-CH2-C≡CH), 1-butynyl (-C≡C-CH2CH3), 2-butynyl (-CH2-C≡C-CH3), 3-butynyl (-CH2CH2-C≡CH), 1-pentynyl (-C≡C-CH2CH2CH3), 2-pentynyl (-CH2-C≡C-CH2CH3), 3-pentynyl (-CH2CH2-C≡C-CH3), and 4-pentynyl (-CH2CH2CH2-C≡CH).

[0104] As the above-mentioned fluoroalkynyl group, preferably it is a group in which at least one hydrogen atom is replaced by a fluorine atom in 2-propynyl (-CH2-C≡CH) and 2-butynyl (-CH2-C≡C-CH3), and more preferably it is -CH2-C≡CF or -CH2-C≡C-CF3.

[0105] As R 111 The unfluorinated alkynyl group mentioned above may contain at least one selected from O and Si in its structure.

[0106] As R 111 Examples of the unfluorinated alkyne groups mentioned above include 1-pentynyl (-C≡C-CH2CH2CH3), 2-pentynyl (-CH2-C≡C-CH2CH3), 3-pentynyl (-CH2CH2-C≡C-CH3), 4-pentynyl (-CH2CH2CH2-C≡CH), -CH2-C≡C-TMS, -CH2-C≡C-TES, -CH2-C≡C-TBDMS, -CH2-C≡C-Si(OCH3)3, and -CH2-C≡C-Si(OC2H5)3.

[0107] As the unfluorinated alkynyl group mentioned above, 2-pentynyl (-CH2-C≡C-CH2CH3), 3-pentynyl (-CH2CH2-C≡C-CH3), -CH2-C≡C-TMS, and -CH2-C≡C-TBDMS are preferred.

[0108] As R 111 The aryl group mentioned above is a group formed by removing one hydrogen atom from an aromatic ring, preferably containing a 6-membered aromatic hydrocarbon ring, and preferably a monocyclic or bicyclic type.

[0109] The aryl group mentioned above can be an unfluorinated aryl group or a fluorinated aryl group. In addition, the structure may contain at least one selected from O and Si.

[0110] Examples of aryl groups include phenyl, tolyl, xylyl, methoxybenzyl, and naphthyl, which may or may not have fluorine atoms. Among these, phenyl groups that may have fluorine atoms are preferred, and phenyl groups that do not have fluorine atoms are more preferred.

[0111] As R 111 Preferably, the above-mentioned fluorinated alkenyl group or the above-mentioned unfluorinated alkynyl group is used.

[0112] As a compound (11), for example, a compound represented by the following formula can be exemplified.

[0113] [Chemistry 18]

[0114]

[0115]

Chemistry 19

[0116]

[0117] As compound (11), preferably a compound represented by the following formula.

[0118]

Chemistry 20

[0119]

[0120] Compound (11) is preferably manufactured by a manufacturing method comprising step (1-1) of reacting compound (a) represented by the following general formula (a) and compound (b) represented by the following general formula (b) to obtain compound (11) represented by the above general formula (11), but is not limited thereto.

[0121] General formula (a):

[0122]

Chemistry 21

[0123]

[0124] (where X) 101 (These are halogen atoms.)

[0125] General formula (b): R 111 -OH(where R is in the formula) 111 Same as above.

[0126] In general formula (a), X 101 It is a halogen atom. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine, with fluorine being the preferred one.

[0127] In the reaction of step (1-1), relative to 1 mole of compound (a), it is preferable to use 0.5 to 2.0 moles of compound (b), more preferably 0.7 to 1.3 moles, and even more preferably 0.9 to 1.1 moles.

[0128] The reaction in step (1-1) is preferably carried out in the presence of a base. Examples of bases include amines and inorganic bases.

[0129] Examples of the aforementioned amines include triethylamine, tri(n-propyl)amine, tri(n-butyl)amine, diisopropylethylamine, cyclohexyldimethylamine, pyridine, dimethylpyridine, γ-trimethylpyridine, N,N-dimethylaniline, N-methylpiperidine, N-methylpyrrolidine, N-methylmorpholine, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene, 1,4-diazabicyclo[2.2.2]octane (DABCO), 4-dimethylaminopyridine (DMAP), and proton sponges.

[0130] Examples of inorganic bases mentioned above include lithium hydroxide, potassium hydroxide, sodium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, cesium carbonate, cesium bicarbonate, lithium bicarbonate, cesium fluoride, potassium fluoride, sodium fluoride, lithium chloride, and lithium bromide.

[0131] The preferred base is an amine, and more preferably triethylamine or pyridine.

[0132] The base used is preferably 1.0 to 2.0 moles relative to 1 mole of compound (a), and more preferably 1.0 to 1.2 moles.

[0133] The reaction in step (1-1) can be carried out with or without a solvent. When carried out in a solvent, an organic solvent is preferred, including non-aromatic hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, decahydronaphthalene, n-decane, isododecane, and tridecane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, tetrahydronaphthalene, veratrine ether, diethylbenzene, methylnaphthalene, nitrobenzene, o-nitrotoluene, mesitylene, indene, and diphenyl sulfide; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzene, diisobutyl ketone, and isophorone; halogenated hydrocarbon solvents such as dichloromethane, carbon tetrachloride, chloroform, and chlorobenzene; and solvents such as diethyl ether, tetrahydrofuran, diisopropyl ether, methyl tert-butyl ether, dioxane, dimethoxyethane, diethylene glycol dimethyl ether, phenethyl ether, and 1,1-dimethyl ether. - Ether solvents such as dimethoxycyclohexane and diisopentyl ether; ester solvents such as ethyl acetate, isopropyl acetate, diethyl malonate, 3-methoxy-3-methylbutylacetate, γ-butyrolactone, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, α-acetyl-γ-butyrolactone; nitrile solvents such as acetonitrile and benzonitrile; sulfoxide solvents such as dimethyl sulfoxide and sulfolane; and amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolium ketone, N,N-dimethylacrylamide, N,N-dimethylacetylacetamide, N,N-diethylformamide, and N,N-diethylacetamide.

[0134] The preferred solvent is a halogenated hydrocarbon solvent, and more preferably dichloromethane, carbon tetrachloride, or chloroform.

[0135] The reaction temperature for step (1-1) is preferably -10 to 70°C, more preferably 0 to 25°C, and even more preferably 0 to 10°C.

[0136] The reaction time for step (1-1) is preferably 0.1 to 72 hours, more preferably 0.1 to 24 hours, and even more preferably 0.1 to 12 hours.

[0137] After each process is completed, the product can be separated and purified by solvent distillation, distillation, column chromatography, recrystallization, etc.

[0138] In general formula (1-2), R 102 and R 103 (i) Independently, H, F, an alkyl group having 1 to 7 carbon atoms that can be fluorinated, an alkenyl group having 2 to 7 carbon atoms that can be fluorinated, an alkynyl group having 2 to 9 carbon atoms that can be fluorinated, or an aryl group having 5 to 12 carbon atoms that can be fluorinated, or (ii) a hydrocarbon group that forms a 5- or 6-membered heterocycle together with a nitrogen atom in a linked manner. R 102 and R 103 The structure may contain at least one of O, S and N.

[0139] As R 102 and R 103 The number of carbon atoms in the alkyl group is preferably 1 to 5, more preferably 1 to 4.

[0140] The alkyl group can be an unfluorinated alkyl group or a fluorinated alkyl group. In addition, it may contain at least one of O, S and N in its structure.

[0141] As R 102 and R 103 Examples of the aforementioned alkyl groups include unfluorinated alkyl groups such as methyl (-CH3), ethyl (-CH2CH3), propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), tert-butyl (-C(CH3)3), isopropyl (-CH(CH3)2), and cyclopropyl (-CHCH2CH2); and -CF3, -CF2H, -CFH2, -CF2CF3, -CF2CF2H, -CF2CFH2, -CH2CF3, -CH2CF2H, -CH2CFH2, and -C. F2CF2CF3, -CF2CF2CF2H, -CF2CF2CFH2, -CH2CF2CF3, -CH2CF2CF2H, -CH2CF2CFH2, -CH2CH2CF3, -CH2CH2CF2H, -CH2CH2CFH 2. -CF(CF3)2, -CF(CF2H)2, -CF(CFH2)2, -CH(CF3)2, -CH(CF2H)2, -CH(CFH2)2, -CH2CF(CF3)OC3F7, -CH2CF2OCF3 and other fluoroalkyl groups, etc.

[0142] The alkyl group described above is preferably methyl, ethyl, isopropyl, tert-butyl, or -CH2CF3.

[0143] As R 102 and R 103 The number of carbon atoms in the alkenyl group is preferably 2 to 5, more preferably 3 to 5.

[0144] The alkenyl group mentioned above can be an unfluorinated alkenyl group or a fluorinated alkenyl group. In addition, the structure may contain at least one of O, S and N.

[0145] As R 102 and R 103Examples of the alkenyl groups mentioned above include vinyl (-CH=CH2), 1-propenyl (-CH=CH-CH3), 1-methylvinyl (-C(CH3)=CH2), 2-propenyl (-CH2-CH=CH2), 1-butenyl (-CH=CH-CH2CH3), 2-methyl-1-propenyl (-CH=C(CH3)-CH3), 1-methyl-1-propenyl (-C(CH3)=CH-CH3), 1-ethylvinyl (-C(CH2CH3)=CH2), 2-butenyl (-CH2-CH=CH-CH3), 2-methyl-2-propenyl (-CH2-C(CH3)=CH2), 1-methyl-2-propenyl (-CH(CH3)-CH=CH2), and 3-butenyl (-CH2CH2-CH=CH=CH2). CH2), 1-methylene-2-propenyl (-C(=CH2)-CH=CH2), 1,3-butadienyl (-CH=CH-CH=CH2), 2,3-butadienyl (-CH2-CH=C=CH2), 1-methyl-1,2-propadienyl (-C(CH3)=C=CH2), 1,2-butadienyl (-CH=C=CH-CH3), 2-pentenyl (-CH2-CH=CH-CH2CH3), 2-ethyl-2-propenyl (-CH2-C(CH2CH3)=CH2), 1-ethyl-2-propenyl (-CH(CH2CH3)-CH=CH2), 3-pentenyl (-CH2CH2-CH=CH-CH3), and groups in which at least one hydrogen atom is replaced by a fluorine atom, etc.

[0146] As the alkenyl group described above, 2-propenyl (-CH2-CH=CH2) and groups formed by replacing at least one hydrogen atom of the 2-propenyl group with a fluorine atom are preferred, and 2-propenyl (-CH2-CH=CH2) is more preferred.

[0147] As R 102 and R 103 The number of carbon atoms in the above-mentioned alkynyl group is preferably 2 to 5, more preferably 3 to 5.

[0148] The aforementioned alkynyl group can be an unfluorinated alkynyl group or a fluorinated alkynyl group. In addition, the structure may contain at least one selected from O, S and N.

[0149] As R 102 and R 103Examples of the aforementioned alkynyl groups include ethynyl (-C≡CH), 1-propynyl (-C≡C-CH3), 2-propynyl (-CH2-C≡CH), 1-butynyl (-C≡C-CH2CH3), 2-butynyl (-CH2-C≡C-CH3), 3-butynyl (-CH2CH2-C≡CH), 1-pentynyl (-C≡C-CH2CH2CH3), 2-pentynyl (-CH2-C≡C-CH2CH3), 3-pentynyl (-CH2CH2-C≡C-CH3), 4-pentynyl (-CH2CH2CH2-C≡CH), and groups formed by replacing at least one hydrogen atom of these groups with a fluorine atom.

[0150] As the aforementioned alkynyl group, 2-propynyl (-CH2-C≡CH), 2-butynyl (-CH2-C≡C-CH3), and groups in which at least one hydrogen atom is replaced by a fluorine atom are preferred, and 2-propynyl (-CH2-C≡CH) is more preferred.

[0151] As R 102 and R 103 The aryl group mentioned above is a group formed by removing one hydrogen atom from an aromatic ring, preferably containing a 6-membered aromatic hydrocarbon ring or an aromatic heterocycle, and preferably a monocyclic or bicyclic type.

[0152] The aryl group mentioned above can be an unfluorinated aryl group or a fluorinated aryl group. In addition, the structure may contain at least one of O, S and N.

[0153] Examples of aryl groups include phenyl, tolyl, xylyl, methoxybenzyl, naphthyl, and pyridyl, which may or may not have fluorine atoms. Among these, phenyl groups that may have fluorine atoms and pyridyl groups that may have fluorine atoms are preferred, and phenyl groups that do not have fluorine atoms and pyridyl groups that do not have fluorine atoms are more preferred.

[0154] As R 102 and R 103 The aforementioned hydrocarbon groups are linked together with nitrogen atoms (the nitrogen atom in the amide bond of general formula (1-2)) to form a 5- or 6-membered heterocycle. The heterocycle is preferably a non-aromatic heterocycle. The number of carbon atoms in the aforementioned hydrocarbon groups is preferably 3 to 5, more preferably 4 to 5. Furthermore, the aforementioned hydrocarbon groups may contain at least one selected from O, S, and N in the structure.

[0155] Examples of such hydrocarbon groups include groups that form a pyrrolidine ring with the nitrogen atom, groups that form a piperidine ring with the nitrogen atom, groups that form an oxazolidine ring with the nitrogen atom, groups that form a morpholine ring with the nitrogen atom, groups that form a thiazole ring with the nitrogen atom, groups that form a 2,5-dihydro-1H-pyrrole ring with the nitrogen atom, groups that form a pyrrole-2,5-diketone ring with the nitrogen atom, and groups that form a 4,5-dihydro-1H-imidazolium ring with the nitrogen atom. Preferably, these groups form a pyrrolidine ring with the nitrogen atom, a piperidine ring with the nitrogen atom, a morpholine ring with the nitrogen atom, a 2,5-dihydro-1H-pyrrole ring with the nitrogen atom, or a pyrrole-2,5-diketone ring with the nitrogen atom.

[0156] R 102 and R 103 Preferably, H and groups other than the aryl groups mentioned above are used.

[0157] R 102 and R 103 Preferably, it does not contain unsaturated bonds. In this case, the increase in resistance of the electrolyte after high-temperature storage can be further suppressed.

[0158] R 102 and R 103 They can be the same or different.

[0159] As compounds (1-2), for example, compounds represented by the following formulas can be exemplified.

[0160]

Chemistry 22

[0161]

[0162] As compounds (1-2), preferably compounds represented by the following formula.

[0163]

Chemistry 23

[0164]

[0165] Among compounds (1-2), compound (12) characterized by the following general formula (12) is a novel compound.

[0166] General formula (12):

[0167]

Chemistry 24

[0168]

[0169] The present invention also relates to compound (12).

[0170] In general formula (12), R 112 and R 113 (i) Independently comprising F, an unfluorinated alkyl group having 1 to 7 carbon atoms, a fluorinated alkyl group having 1 to 5 carbon atoms, an alkenyl group having 3 to 7 carbon atoms that can be fluorinated, or an alkynyl group having 3 to 7 carbon atoms that can be fluorinated, and R 112 and R 113 At least one of them is F, an unfluorinated alkyl group having 3 to 7 carbon atoms, a fluorinated alkyl group having 1 to 5 carbon atoms, an alkenyl group having 3 to 7 carbon atoms that can be fluorinated, or an alkynyl group having 3 to 7 carbon atoms that can be fluorinated, or (ii) a hydrocarbon group that is linked together with a nitrogen atom to form a 5- or 6-membered heterocycle. R 112 and R 113 The structure may contain at least one of O, S and N.

[0171] As R 112 and R 113 The unfluorinated alkyl group described above preferably has 1 to 6 carbon atoms, more preferably 1 to 5. The unfluorinated alkyl group may have an ether bond in its structure.

[0172] Examples of unfluorinated alkyl groups include methyl (-CH3), ethyl (-CH2CH3), propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), cyclopropyl (-CHCH2CH2), n-butyl (-CH2CH2CH2CH3), and tert-butyl (-C(CH3)3). Among these, methyl, ethyl, isopropyl, and tert-butyl are preferred.

[0173] As R 112 and R 113 The fluoroalkyl group described above preferably has 1 to 4 carbon atoms, and more preferably 1 to 3 carbon atoms. The fluoroalkyl group may have an ether bond in its structure.

[0174] Examples of fluoroalkyl groups include -CF3, -CF2H, -CFH2, -CF2CF3, -CF2CF2H, -CF2CFH2, -CH2CF3, -CH2CF2H, -CH2CFH2, -CF2CF2CF3, -CF2CF2CF2H, -CF2CF2CFH2, -CH2CF2CF3, -CH2CF2CF2H, -CH2CF2CFH2, -CH2CH2CF3, -CH2CH2CF2H, -CH2CH2CFH2, -CF(CF3)2, -CF(CF2H)2, -CF(CFH2)2, -CH(CF3)2, -CH(CF2H)2, -CH(CFH2)2, -CH2CF(CF3)OC3F7, and -CH2CF2OCF3. Among these, -CH2CF3 is preferred.

[0175] As R 112 and R 113 The number of carbon atoms in the alkenyl group is preferably 3 to 5, more preferably 3 to 4.

[0176] The alkenyl group mentioned above can be an unfluorinated alkenyl group or a fluorinated alkenyl group. In addition, it can also have an ether bond in the structure.

[0177] As R 112 and R 113 Examples of the alkenyl groups mentioned above include 1-propenyl (-CH=CH-CH3), 1-methyl vinyl (-C(CH3)=CH2), 2-propenyl (-CH2-CH=CH2), 1-butenyl (-CH=CH-CH2CH3), 2-methyl-1-propenyl (-CH=C(CH3)-CH3), 1-methyl-1-propenyl (-C(CH3)=CH-CH3), 1-ethyl vinyl (-C(CH2CH3)=CH2), 2-butenyl (-CH2-CH=CH-CH3), 2-methyl-2-propenyl (-CH2-C(CH3)=CH2), 1-methyl-2-propenyl (-CH(CH3)-CH=CH2), 3-butenyl (-CH2CH2-CH=CH2), 1 -methylene-2-propenyl (-C(=CH2)-CH=CH2), 1,3-butadienyl (-CH=CH-CH=CH2), 2,3-butadienyl (-CH2-CH=C=CH2), 1-methyl-1,2-propadienyl (-C(CH3)=C=CH2), 1,2-butadienyl (-CH=C=CH-CH3), 2-pentenyl (-CH2-CH=CH-CH2CH3), 2-ethyl-2-propenyl (-CH2-C(CH2CH3)=CH2), 1-ethyl-2-propenyl (-CH(CH2CH3)-CH=CH2), 3-pentenyl (-CH2CH2-CH=CH-CH3), and groups in which at least one hydrogen atom is replaced by a fluorine atom.

[0178] As the alkenyl group described above, 2-propenyl (-CH2-CH=CH2) and groups formed by replacing at least one hydrogen atom of the 2-propenyl group with a fluorine atom are preferred, and 2-propenyl (-CH2-CH=CH2) is more preferred.

[0179] As R 112 and R 113 The number of carbon atoms in the aforementioned alkynyl group is preferably 3 to 5, more preferably 3 to 4.

[0180] The aforementioned alkynyl group can be an unfluorinated alkynyl group or a fluorinated alkynyl group. In addition, it can also have an ether bond in the structure.

[0181] As R 112 and R 113 Examples of the aforementioned alkynyl groups include 1-propynyl (-C≡C-CH3), 2-propynyl (-CH2-C≡CH), 1-butynyl (-C≡C-CH2CH3), 2-butynyl (-CH2-C≡C-CH3), 3-butynyl (-CH2CH2-C≡CH), 1-pentynyl (-C≡C-CH2CH2CH3), 2-pentynyl (-CH2-C≡C-CH2CH3), 3-pentynyl (-CH2CH2-C≡C-CH3), 4-pentynyl (-CH2CH2CH2-C≡CH), and groups formed by replacing at least one hydrogen atom with a fluorine atom in these groups.

[0182] As the aforementioned alkynyl group, 2-propynyl (-CH2-C≡CH) is preferred.

[0183] As R 112 and R 113 The aforementioned hydrocarbon groups are linked together to form a 5- or 6-membered heterocycle with a nitrogen atom (the nitrogen atom in the amide bond of general formula (12)). The aforementioned heterocycle is preferably a non-aromatic heterocycle. The number of carbon atoms in the aforementioned hydrocarbon groups is preferably 3 to 5, more preferably 4 to 5. In addition, the aforementioned hydrocarbon groups may contain at least one of O, S and N in the structure.

[0184] Examples of such hydrocarbon groups include groups that form a pyrrolidine ring with the nitrogen atom, groups that form a piperidine ring with the nitrogen atom, groups that form an oxazolidine ring with the nitrogen atom, groups that form a morpholine ring with the nitrogen atom, groups that form a thiazole ring with the nitrogen atom, groups that form a 2,5-dihydro-1H-pyrrole ring with the nitrogen atom, groups that form a pyrrole-2,5-diketone ring with the nitrogen atom, and groups that form a 4,5-dihydro-1H-imidazolium ring with the nitrogen atom. Preferably, these groups form a pyrrolidine ring with the nitrogen atom, a piperidine ring with the nitrogen atom, a morpholine ring with the nitrogen atom, a 2,5-dihydro-1H-pyrrole ring with the nitrogen atom, or a pyrrole-2,5-diketone ring with the nitrogen atom.

[0185] R 112 and R 113 Preferably, at least one of them is F, the above-mentioned fluoroalkyl, the above-mentioned alkenyl or the above-mentioned alkynyl.

[0186] R 112 and R 113 They can be the same or different.

[0187] As a compound (12), for example, compounds represented by the following formula can be exemplified.

[0188]

Chemistry 25

[0189]

[0190] As compound (12), preferably a compound represented by the following formula.

[0191]

Chemistry 26

[0192]

[0193] Compound (12) is preferably manufactured by the manufacturing method of step (1-2) of reacting compound (a) represented by the following general formula (a) and compound (c) represented by the following general formula (c) to obtain compound (12) represented by the above general formula (12), but is not limited thereto.

[0194] General formula (a):

[0195]

Chemistry 27

[0196]

[0197] (where X) 101 (These are halogen atoms.)

[0198] General formula (c):

[0199]

Chemistry 28

[0200]

[0201] (where R is in the formula) 112 and R 113 Same as above.

[0202] In general formula (a), X 101 It is a halogen atom. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine, with fluorine being the preferred one.

[0203] In the reaction of step (1-2), relative to 1 mole of compound (a), it is preferable to use 0.5 to 4.0 moles of compound (c), more preferably 0.7 to 3.0 moles, and even more preferably 0.9 to 2.2 moles.

[0204] The reaction in step (1-2) is preferably carried out in the presence of a base. Examples of bases include amines and inorganic bases.

[0205] Examples of the amines mentioned above include triethylamine, tri(n-propyl)amine, tri(n-butyl)amine, diisopropylethylamine, cyclohexyldimethylamine, pyridine, dimethylpyridine, γ-trimethylpyridine, N,N-dimethylaniline, N-methylpiperidine, N-methylpyrrolidine, N-methylmorpholine, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene, 1,4-diazabicyclo[2.2.2]octane (DABCO), 4-dimethylaminopyridine (DMAP), proton sponges, etc. Compound (c) used as a reaction raw material is also included in the above amines.

[0206] Examples of inorganic bases mentioned above include lithium hydroxide, potassium hydroxide, sodium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, cesium carbonate, cesium bicarbonate, lithium bicarbonate, cesium fluoride, potassium fluoride, sodium fluoride, lithium chloride, and lithium bromide.

[0207] As the aforementioned base, an amine is preferred. It may be used in combination with compound (c), which is a reactant, and an amine other than compound (c), or they may not be used together. As an amine other than compound (c), triethylamine or pyridine are preferred.

[0208] When using a base other than compound (c) as the base, it is preferable to use 1.0 to 2.0 moles of compound (a) and more preferably 1.0 to 1.2 moles of compound (a).

[0209] The reaction in steps (1-2) can be carried out with or without a solvent. When carried out with a solvent, organic solvents are preferred, including non-aromatic hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, decahydronaphthalene, n-decane, isododecane, and tridecane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, tetrahydronaphthalene, veratrine ether, diethylbenzene, methylnaphthalene, nitrobenzene, o-nitrotoluene, mesitylene, indene, and diphenyl sulfide; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, phenylacetone, diisobutyl ketone, and isophorone; halogenated hydrocarbon solvents such as dichloromethane, carbon tetrachloride, chloroform, and chlorobenzene; and solvents such as diethyl ether, tetrahydrofuran, diisopropyl ether, methyl tert-butyl ether, dioxane, dimethoxyethane, diethylene glycol dimethyl ether, phenethyl ether, and 1,1-dimethyl ether. - Ether solvents such as dimethoxycyclohexane and diisopentyl ether; ester solvents such as ethyl acetate, isopropyl acetate, diethyl malonate, 3-methoxy-3-methylbutylacetate, γ-butyrolactone, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, and α-acetyl-γ-butyrolactone; nitrile solvents such as acetonitrile and benzonitrile; sulfoxide solvents such as dimethyl sulfoxide and sulfolane; and amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolium ketone, N,N-dimethylacrylamide, N,N-dimethylacetylacetamide, N,N-diethylformamide, and N,N-diethylacetamide.

[0210] The preferred solvent is a halogenated hydrocarbon solvent, and more preferably dichloromethane, carbon tetrachloride, or chloroform.

[0211] The reaction temperature for step (1-2) is preferably -10 to 70°C, more preferably 0 to 25°C, and even more preferably 0 to 10°C.

[0212] The reaction time for process (1-2) is preferably 0.1 to 72 hours, more preferably 0.1 to 24 hours, and even more preferably 0.1 to 12 hours.

[0213] After each process is completed, the product can be separated and purified by solvent distillation, distillation, column chromatography, recrystallization, etc.

[0214] Compound (1) can be used alone or in combination with two or more compounds.

[0215] The electrolyte of the present invention preferably contains 0.001 to 10% by mass of compound (1) relative to the electrolyte content. If the content of compound (1) is within the above range, the high-temperature storage characteristics and cycle characteristics of the electrochemical device can be further improved. The content of compound (1) is more preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and particularly preferably 0.1% by mass or more. In addition, it is more preferably 7% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less.

[0216] The electrolyte of the present invention preferably contains a solvent (wherein, it does not include compound (1)).

[0217] The solvents described above preferably contain at least one selected from carbonates and carboxylic esters.

[0218] The aforementioned carbonates can be cyclic carbonates or chain carbonates.

[0219] The aforementioned cyclic carbonates can be either unfluorinated cyclic carbonates or fluorinated cyclic carbonates.

[0220] Examples of unfluorinated cyclic carbonates include unfluorinated saturated cyclic carbonates, preferably unfluorinated saturated alkyl carbonates having 2 to 6 carbon atoms, and more preferably unfluorinated saturated alkyl carbonates having 2 to 4 carbon atoms.

[0221] Among them, the unfluorinated saturated cyclic carbonate is preferably selected from at least one of ethylene carbonate, propylene carbonate, cis-pentenyl carbonate, cis-butenyl carbonate, 2,3-pentenyl carbonate, 2,3-butenyl carbonate, 1,2-pentenyl carbonate, 1,2-butenyl carbonate and butenyl carbonate, considering high dielectric constant and suitable viscosity.

[0222] The aforementioned unfluorinated saturated cyclic carbonates can be used alone or in any combination and ratio of two or more.

[0223] In the case of containing the above-mentioned unfluorinated saturated cyclic carbonate, the content of the above-mentioned unfluorinated saturated cyclic carbonate relative to the above-mentioned solvent is preferably 5 to 90% by volume, more preferably 10 to 60% by volume, and even more preferably 15 to 45% by volume.

[0224] The aforementioned fluorinated cyclic carbonates are cyclic carbonates containing fluorine atoms. Solvents containing fluorinated cyclic carbonates can be used appropriately even at high voltages.

[0225] In addition, in this specification, "high voltage" refers to a voltage of 4.2V or higher. Furthermore, the upper limit of "high voltage" is preferably 4.9V.

[0226] The aforementioned fluorinated cyclic carbonates can be either fluorinated saturated cyclic carbonates or fluorinated unsaturated cyclic carbonates.

[0227] The aforementioned fluorinated saturated cyclic carbonates are saturated cyclic carbonates having fluorine atoms. Specifically, compounds represented by the following general formula (A) can be cited:

[0228]

Chemistry 29

[0229]

[0230] (where X) 1 ~X 4 "Same" or "different" respectively represent -H, -CH3, -C2H5, -F, fluoroalkyl groups that may have ether bonds, or fluoroalkoxy groups that may have ether bonds. Where X... 1 ~X 4 At least one of them is -F, a fluoroalkyl group that may have an ether bond, or a fluoroalkoxy group that may have an ether bond. The aforementioned fluoroalkyl groups are -CF3, -CF2H, -CH2F, etc.

[0231] If the electrolyte contains the aforementioned fluorinated saturated cyclic carbonate, its oxidation resistance is improved when the electrolyte is applied to high-voltage lithium-ion secondary batteries, etc., resulting in stable and excellent charge-discharge characteristics.

[0232] It should be noted that in this specification, "ether bond" is a bond represented by -O-.

[0233] From the perspectives of dielectric constant and good oxidation resistance, X 1 ~X 4 One or two of them are preferably -F, fluoroalkyl groups that may have ether bonds, or fluoroalkoxy groups that may have ether bonds.

[0234] Based on the expected decrease in viscosity, increase in flash point, and improvement in the solubility of electrolyte salts at low temperatures, X 1 ~X 4 Preferably, it is -H, -F, fluoroalkyl (a), fluoroalkyl with an ether bond (b), or fluoroalkoxy (c).

[0235] The aforementioned fluoroalkyl group (a) is a group formed by replacing at least one of the hydrogen atoms in an alkyl group with a fluorine atom. The number of carbon atoms in the fluoroalkyl group (a) is preferably 1 to 20, more preferably 1 to 17, even more preferably 1 to 7, and particularly preferably 1 to 5.

[0236] If the number of carbon atoms is too large, the low-temperature characteristics may be reduced, or the solubility of the electrolyte salt may be reduced. If the number of carbon atoms is too small, sometimes the solubility of the electrolyte salt, the discharge efficiency, and the viscosity are reduced.

[0237] Examples of groups with one carbon atom in the aforementioned fluoroalkyl(a) include CFH2-, CF2H-, and CF3-. CF2H- or CF3- are particularly preferred for high-temperature storage properties, with CF3- being the most preferred.

[0238] As the fluoroalkyl group (a) mentioned above, the group having 2 or more carbon atoms is preferably represented by the following general formula (a-1) from the viewpoint of good solubility in electrolyte salts.

[0239] R 1 -R 2 - (a-1)

[0240] (where R is in the formula) 1 It can be an alkyl group having 1 or more carbon atoms and containing fluorine atoms; R 2 This refers to an alkylene group having 1 to 3 carbon atoms that can have fluorine atoms; wherein, R 1 and R 2 (At least one of them has a fluorine atom).

[0241] It should be noted that R 1 and R 2 It can also have other atoms besides carbon, hydrogen, and fluorine atoms.

[0242] R 1 It can be an alkyl group having one or more carbon atoms and containing fluorine atoms. As R 1 Preferably, it is a straight-chain or branched alkyl group having 1 to 16 carbon atoms. As R 1 The number of carbon atoms is more preferably 1 to 6, and even more preferably 1 to 3.

[0243] As R 1 Specifically, examples of linear or branched alkyl groups include CH3-, CH3CH2-, CH3CH2CH2-, and CH3CH2CH2CH2-.

[0244]

Transformation 30

[0245]

[0246] wait.

[0247] Additionally, in R 1Examples of linear alkyl groups having fluorine atoms include CF3-, CF3CH2-, CF3CF2-, CF3CH2CH2-, CF3CF2CH2-, CF3CF2CF2-, CF3CH2CF2-, CF3CH2CH2CH2-, CF3CF2CH2CH2-, CF3CH2CF2CH2-, CF3CF2CF2CH2-, CF3CF2CF2CF2-, CF3CF2CH2CF2-, CF3CH2CH2CH2CH2-, and CF3CF2CH2CH2C. H2-, CF3CH2CF2CH2CH2-, CF3CF2CF2CH2CH2-, CF3CF2CF2CF2CH2-, CF3CF2CH2CF2CH2-, CF3CF2CH2CH2CH2CH2-, CF3CF2CF 2CF2CH2CH2-, CF3CF2CH2CF2CH2CH2-, HCF2-, HCF2CH2-, HCF2CF2-, HCF2CH2CH2-, HCF2CF2CH2-, HCF2CH2CF2-, HCF2CF2C H2CH2-, HCF2CH2CF2CH2-, HCF2CF2CF2CF2-, HCF2CF2CH2CH2CH2-, HCF2CH2CF2CH2CH2-, HCF2CF2CF2CF2CH2-, HCF2CF2C F2CF2CH2CH2-, FCH2-, FCH2CH2-, FCH2CF2-, FCH2CF2CH2-, FCH2CF2CF2-, CH3CF2CH2-, CH3CF2CF2-, CH3CF2CH2CF2-, CH3 CF2CF2CF2-, CH3CH2CF2CF2-, CH3CF2CH2CF2CH2-, CH3CF2CF2CF2CH2-, CH3CF2CF2CH2CH2-, CH3CH2CF2CF2CH2-, CH3CF2C H2CF2CH2CH2-, CH3CF2CH2CF2CH2CH2-, HCFClCF2CH2-, HCF2CFClCH2-, HCF2CFClCF2CFClCH2-, HFCClCF2CFClCF2CH2-, etc.

[0248] Additionally, in R 1 In the case of a branched alkyl group having fluorine atoms, the following are preferred examples.

[0249]

Chemistry 31

[0250]

[0251]

Chemistry 32

[0252]

[0253] And so on. Among them, if it has branches such as CH3- and CF3-, the viscosity tends to be higher. Therefore, it is more preferable to have fewer (1) or zero branches.

[0254] R 2 It can be an alkylene group having 1 to 3 carbon atoms and containing fluorine atoms. R 2 It can be linear or branched. The following shows examples of the smallest structural units constituting such linear or branched alkylene groups. R 2 It consists of them individually or in combination.

[0255] (i) The smallest structural unit in a linear chain:

[0256] -CH2-, -CHF-, -CF2-, -CHCl-, -CFCl-, -CCl2-

[0257] (ii) Branched minimum structural unit:

[0258]

Transformation 33

[0259]

[0260] It should be noted that, in the above examples, from the perspective of avoiding the deHCl reaction caused by alkali and achieving greater stability, it is preferable to be composed of structural units that do not contain Cl.

[0261] In R 2 In the case of a linear structure, it is composed only of the aforementioned linear minimum structural units, preferably -CH2-, -CH2CH2-, or -CF2-. From the viewpoint of further improving the solubility of the electrolyte salt, -CH2- or -CH2CH2- is more preferred.

[0262] In R 2 In the case of a branched structure, containing at least one of the aforementioned branched minimum structural units, the general formula -(CX) can be preferably exemplified. a X b )-(X a For H, F, CH3 or CF3; X b It is CH3 or CF3. Wherein, in X b In the case of CF3, X a These are units represented by H or CH3. These units, in particular, can further improve the solubility of electrolyte salts.

[0263] Preferred fluoroalkyl groups (a) include, for example, CF3CF2-, HCF2CF2-, H2CFCF2-, CH3CF2-, CF3CHF-, CH3CF2-, CF3CF2CF2-, HCF2CF2CF2-, H2CFCF2CF2-, CH3CF2CF2-.

[0264]

Transformation 34

[0265]

[0266]

Chemistry 35

[0267]

[0268] wait.

[0269] The aforementioned fluoroalkyl group (b) with an ether bond is a group formed by replacing at least one of the hydrogen atoms in the alkyl group with an ether bond with a fluorine atom. The number of carbon atoms in the aforementioned fluoroalkyl group (b) with an ether bond is preferably 2 to 17. If the number of carbon atoms is too high, the viscosity of the aforementioned fluorinated saturated cyclic carbonate increases. Furthermore, due to the increased number of fluorine-containing groups, a decrease in the solubility of the electrolyte salt and a decrease in compatibility with other solvents due to a decrease in the dielectric constant can sometimes be observed. From this perspective, the number of carbon atoms in the aforementioned fluoroalkyl group (b) with an ether bond is more preferably 2 to 10, and even more preferably 2 to 7.

[0270] The alkylene group constituting the ether portion of the fluoroalkyl group (b) having an ether bond described above can be a straight-chain or branched alkylene group. Examples of the smallest structural units constituting such straight-chain or branched alkylene groups are shown below.

[0271] (i) The smallest structural unit in a linear chain:

[0272] -CH2-, -CHF-, -CF2-, -CHCl-, -CFCl-, -CCl2-

[0273] (ii) Branched minimum structural unit:

[0274]

Transformation 36

[0275]

[0276] Alkylenes can be composed of a single one of these smallest structural units, or they can be composed of multiple linear (i), multiple branched (ii), or a combination of linear (i) and branched (ii). Preferred examples are described later.

[0277] It should be noted that, in the above examples, from the perspective of avoiding the deHCl reaction caused by alkali and achieving greater stability, it is preferable to be composed of structural units that do not contain Cl.

[0278] As a further preferred fluoroalkyl group having an ether bond (b), examples include groups represented by general formula (b-1).

[0279] R 3 -(OR 4 ) n1 - (b-1)

[0280] (where R is in the formula) 3 It may be an alkyl group having fluorine atoms, preferably with 1 to 6 carbon atoms; R 4 It is an alkylene group that may have fluorine atoms, preferably with 1 to 4 carbon atoms; n1 is an integer from 1 to 3; wherein, R 3 and R 4 (At least one of them has a fluorine atom).

[0281] As R 3 and R 4 Examples of such groups are given, which can be appropriately combined to form a fluoroalkyl group (b) with an ether bond represented by the above general formula (b-1), but are not limited to these.

[0282] (1) As R 3 Preferably, the general formula is: X c 3C-(R 5 ) n2 -(3 X's) c Whether they are the same or different, both are H or F; R 5 It is an alkylene group having 1 to 5 carbon atoms and may have fluorine atoms; n2 is an alkyl group represented by 0 or 1).

[0283] When n2 is 0, as R 3 Examples include CH3-, CF3-, HCF2-, and H2CF-.

[0284] As a specific example when n2 is 1, as R 3Examples of linear groups include CF3CH2-, CF3CF2-, CF3CH2CH2-, CF3CF2CH2-, CF3CF2CF2-, CF3CH2CF2-, CF3CH2CH2CH2-, CF3CF2CH2CH2-, CF3CH2CF2CH2-, CF3CF2CF2CH2-, CF3CF2CF2CF2-, CF3CF2CH2CF2-, CF3CH2CH2CH2CH2-, CF3CF2CH2CH2CH2- , CF3CH2CF2CH2CH2-, CF3CF2CF2CH2CH2-, CF3CF2CF2CF2CH2-, CF3CF2CH2CF2CH2-, CF3CF2CH2CH2CH2CH2-, CF3CF 2CF2CF2CH2CH2-, CF3CF2CH2CF2CH2CH2-, HCF2CH2-, HCF2CF2-, HCF2CH2CH2-, HCF2CF2CH2-, HCF2CH2CF2-, HCF2CF 2CH2CH2-, HCF2CH2CF2CH2-, HCF2CF2CF2CF2-, HCF2CF2CH2CH2CH2-, HCF2CH2CF2CH2CH2-, HCF2CF2CF2CF2CH2-, H CF2CF2CF2CF2CH2CH2-, FCH2CH2-, FCH2CF2-, FCH2CF2CH2-, CH3CF2-, CH3CH2-, CH3CF2CH2-, CH3CF2CF2-, CH3CH2C H2-, CH3CF2CH2CF2-, CH3CF2CF2CF2-, CH3CH2CF2CF2-, CH3CH2CH2CH2-, CH3CF2CH2CF2CH2-, CH3CF2CF2CF2CH2-, CH3CF2CF2CH2CH2-, CH3CH2CF2CF2CH2-, CH3CF2CH2CF2CH2CH2-, CH3CH2CF2CF2CH2CH2-, CH3CF2CH2CF2CH2CH2-, etc.

[0285] As n2 is 1 and R 3 Branched groups can be listed as examples.

[0286]

Chemistry 37

[0287]

[0288] wait.

[0289] If it has branches such as CH3- and CF3-, the viscosity tends to increase, therefore R 3 More preferably, it is a straight-chain group.

[0290] (2) The -(OR) in the above general formula (b-1) 4 ) n1 In this context, n1 is an integer from 1 to 3, preferably 1 or 2. It should be noted that when n1 = 2 or 3, R... 4 They can be the same or different.

[0291] As R 4 Preferred specific examples may include the following straight-chain or branched groups.

[0292] Examples of linear groups include -CH2-, -CHF-, -CF2-, -CH2CH2-, -CF2CH2-, -CF2CF2-, -CH2CF2-, -CH2CH2CH2-, -CH2CH2CF2-, -CH2CF2CH2-, -CH2CF2CF2-, -CF2CH2CH2-, -CF2CF2CH2-, -CF2CH2CF2-, -CF2CF2CF2-, and so on.

[0293] Examples of branched groups include

[0294]

Transformation 38

[0295]

[0296] wait.

[0297] The aforementioned fluoroalkoxy group (c) is a group formed by replacing at least one of the hydrogen atoms in an alkoxy group with a fluorine atom. The number of carbon atoms in the aforementioned fluoroalkoxy group (c) is preferably 1 to 17. More preferably, it is 1 to 6.

[0298] As the aforementioned fluoroalkoxy group (c), it is particularly preferred to be of the general formula: X d 3C-(R 6 ) n3 -O-(3 X's) d Whether they are the same or different, both are H or F; R 6 Preferably, it is an alkylene group having 1 to 5 carbon atoms and may contain fluorine atoms; n3 is 0 or 1; wherein, 3 X atoms d The fluoroalkoxy group is represented by at least one fluorine atom.

[0299] As a specific example of the aforementioned fluoroalkoxy group (c), one can cite R as an example of the aforementioned general formula (a-1). 1 The fluoroalkoxy group is exemplified by the terminal alkyl group bonded with an oxygen atom.

[0300] The fluorine content of the fluoroalkyl group (a), the fluoroalkyl group having an ether bond (b), and the fluoroalkoxy group (c) in the above-mentioned fluorosaturated cyclic carbonate is preferably 10% by mass or more. If the fluorine content is too low, the viscosity reduction effect at low temperature and the flash point increase effect may not be sufficiently obtained. From this point of view, the fluorine content is more preferably 12% by mass or more, and even more preferably 15% by mass or more. The upper limit is usually 76% by mass.

[0301] The fluorine content of fluoroalkyl (a), fluoroalkyl with ether bond (b), and fluoroalkoxy (c) is calculated based on the structural formula of each group by [(number of fluorine atoms × 19) / formula weight of each group] × 100 (%).

[0302] Furthermore, considering the dielectric constant and good oxidation resistance, the overall fluorine content of the aforementioned fluorinated saturated cyclic carbonate is preferably 10% by mass or more, more preferably 15% by mass or more. The upper limit is typically 76% by mass.

[0303] It should be noted that the fluorine content of the above-mentioned fluorinated saturated cyclic carbonates is a value calculated based on the structural formula of the fluorinated saturated cyclic carbonates by using [(number of fluorine atoms × 19) / molecular weight of the fluorinated saturated cyclic carbonate] × 100 (%).

[0304] Specifically, examples of the aforementioned fluorinated saturated cyclic carbonates include the following substances.

[0305] As X 1 ~X 4 Specific examples of fluorosaturated cyclic carbonates in which at least one is -F can be cited.

[0306]

Chemistry 39

[0307]

[0308] These compounds have high voltage resistance and good solubility in electrolyte salts.

[0309] In addition, it can also be used

[0310]

Chemistry 40

[0311]

[0312] wait.

[0313] As X 1 ~X 4 Specific examples of fluorosaturated cyclic carbonates in which at least one alkyl group (a) is fluoroalkyl and the remainder is all -H include:

[0314]

Chemistry 41

[0315]

[0316]

Chemistry 42

[0317]

[0318]

Chemistry 43

[0319]

[0320] wait.

[0321] As X 1 ~X 4 Specific examples of fluorosaturated cyclic carbonates in which at least one of the constituents is a fluoroalkyl group (b) or a fluoroalkoxy group (c) having an ether bond, and the remainder being all -H, can be cited as follows:

[0322]

Chemistry 44

[0323]

[0324]

Chemistry 45

[0325]

[0326]

Chemistry 46

[0327]

[0328]

Chemistry 47

[0329]

[0330]

Chemistry 48

[0331]

[0332]

Chemistry 49

[0333]

[0334] wait.

[0335] Among them, the fluorinated saturated cyclic carbonate is preferably any one of the following compounds.

[0336] [Transformation 50]

[0337]

[0338]

Chemistry 51

[0339]

[0340] Other examples of fluorinated saturated cyclic carbonates include trans-4,5-difluoro-1,3-dioxapentane-2-one, 5-(1,1-difluoroethyl)-4,4-difluoro-1,3-dioxapentane-2-one, 4-methylene-1,3-dioxapentane-2-one, 4-methyl-5-trifluoromethyl-1,3-dioxapentane-2-one, 4-ethyl-5-fluoro-1,3-dioxapentane-2-one, and 4-ethyl-5,5-difluoro-1,3-dioxapentane-2-one. 3-Dioxapentane-2-one, 4-ethyl-4,5-difluoro-1,3-dioxapentane-2-one, 4-ethyl-4,5,5-trifluoro-1,3-dioxapentane-2-one, 4,4-difluoro-5-methyl-1,3-dioxapentane-2-one, 4-fluoro-5-methyl-1,3-dioxapentane-2-one, 4-fluoro-5-trifluoromethyl-1,3-dioxapentane-2-one, 4,4-difluoro-1,3-dioxapentane-2-one, etc.

[0341] The fluorinated saturated cyclic carbonates described above are preferably fluoroethylene carbonate, difluoroethylene carbonate, trifluoromethyl ethylene carbonate (3,3,3-trifluoropropylene carbonate), or 2,2,3,3,3-pentafluoropropyl ethylene carbonate.

[0342] The aforementioned fluorinated unsaturated cyclic carbonates are cyclic carbonates having unsaturated bonds and fluorine atoms, preferably fluorinated vinyl carbonate derivatives substituted with substituents having aromatic rings or carbon-carbon double bonds. Specifically, examples include 4,4-difluoro-5-phenylvinyl carbonate, 4,5-difluoro-4-phenylvinyl carbonate, 4-fluoro-5-phenylvinyl carbonate, 4-fluoro-5-vinylvinyl carbonate, 4-fluoro-4-phenylvinyl carbonate, 4,4-difluoro-4-vinylvinyl carbonate, 4,4-difluoro-4-allyl vinyl carbonate, 4-fluoro-4-vinylvinyl carbonate, 4-fluoro-4,5-diallyl vinyl carbonate, 4,5-difluoro-4,5-vinylvinyl carbonate, 4,5-difluoro-4,5-divinylvinyl carbonate, and 4,5-difluoro-4,5-diallyl vinyl carbonate.

[0343] The above-mentioned fluorocyclic carbonates can be used alone or in any combination and ratio of two or more.

[0344] In the case of containing the above-mentioned fluorinated cyclic carbonate, the content of the above-mentioned fluorinated cyclic carbonate relative to the above-mentioned solvent is preferably 5 to 90% by volume, more preferably 10 to 60% by volume, and even more preferably 15 to 45% by volume.

[0345] The aforementioned chain carbonates can be unfluorinated chain carbonates or fluorinated chain carbonates.

[0346] Examples of unfluorinated chain carbonates include CH3OCOOCH3 (dimethyl carbonate: DMC), CH3CH2OCOOCH2CH3 (diethyl carbonate: DEC), CH3CH2OCOOCH3 (ethyl methyl carbonate: EMC), CH3OCOOCH2CH2CH3 (methyl propyl carbonate), methyl butyl carbonate, ethyl propyl carbonate, ethyl butyl carbonate, dipropyl carbonate, dibutyl carbonate, methyl isopropyl carbonate, methyl-2-phenylphenyl carbonate, phenyl-2-phenylphenyl carbonate, trans-2,3-pentenyl carbonate, trans-2,3-butenyl carbonate, and ethyl phenyl carbonate. Preferably, at least one of ethyl methyl carbonate, diethyl carbonate, and dimethyl carbonate is selected.

[0347] The aforementioned unfluorinated chain carbonates can be used alone or in combination with two or more in any combination and ratio.

[0348] In the case of containing the above-mentioned unfluorinated chain carbonate, the content of the above-mentioned unfluorinated chain carbonate relative to the above-mentioned solvent is preferably 10 to 90% by volume, more preferably 40 to 85% by volume, and even more preferably 50 to 80% by volume.

[0349] The aforementioned fluorinated chain carbonates are chain carbonates containing fluorine atoms. Solvents containing fluorinated chain carbonates can be used appropriately even at high voltages.

[0350] Examples of the aforementioned fluorinated chain carbonates include compounds represented by general formula (B):

[0351] Rf 2 OCOOR 7 (B)

[0352] (where Rf) 2 It is a fluoroalkyl group with 1 to 7 carbon atoms, R 7 Alkyl groups having 1 to 7 carbon atoms and may contain fluorine atoms.

[0353] Rf 2 It is a fluoroalkyl group with 1 to 7 carbon atoms, R 7 Alkyl groups having 1 to 7 carbon atoms may contain fluorine atoms.

[0354] The aforementioned fluoroalkyl group is formed by replacing at least one of the hydrogen atoms in an alkyl group with a fluorine atom. In R 7 If it is an alkyl group containing a fluorine atom, it is a fluoroalkyl group.

[0355] From the perspective of low viscosity, Rf 2 and R 7 The number of carbon atoms is preferably 1 to 7, more preferably 1 to 2.

[0356] If the number of carbon atoms is too large, the low-temperature characteristics may be reduced, or the solubility of the electrolyte salt may be reduced; if the number of carbon atoms is too small, sometimes a decrease in the solubility of the electrolyte salt, a decrease in discharge efficiency, or even an increase in viscosity are observed.

[0357] Examples of fluoroalkyl groups with one carbon atom include CFH2-, CF2H-, and CF3-. In particular, CFH2- or CF3- are preferred for high-temperature storage properties.

[0358] From the perspective of good solubility in electrolyte salts, the following general formula (d-1) is preferred as a fluoroalkyl group having 2 or more carbon atoms:

[0359] R 1 -R 2 -(d-1)

[0360] (where R is in the formula) 1 It can be an alkyl group having 1 or more carbon atoms and containing fluorine atoms; R 2 This refers to an alkylene group having 1 to 3 carbon atoms that can have fluorine atoms; wherein, R 1 and R 2 At least one of them has a fluorine atom) representing a fluoroalkyl group.

[0361] It should be noted that R 1 and R 2 It can also have other atoms besides carbon, hydrogen, and fluorine atoms.

[0362] R 1 It can be an alkyl group having one or more carbon atoms and containing fluorine atoms. As R 1 Preferably, it is a straight-chain or branched alkyl group having 1 to 6 carbon atoms. As R 1 The number of carbon atoms is more preferably 1 to 3.

[0363] As R 1 Specifically, examples of linear or branched alkyl groups include CH3-, CF3-, CH3CH2-, CH3CH2CH2-, and CH3CH2CH2CH2-.

[0364]

Chemistry 52

[0365]

[0366] wait.

[0367] Additionally, in R 1Examples of linear alkyl groups having fluorine atoms include CF3-, CF3CH2-, CF3CF2-, CF3CH2CH2-, CF3CF2CH2-, CF3CF2CF2-, CF3CH2CF2-, CF3CH2CH2CH2-, CF3CF2CH2CH2-, CF3CH2CF2CH2-, CF3CF2CF2CH2-, CF3CF2CF2CF2-, CF3CF2CH2CF2-, CF3CH2CH2CH2CH2-, and CF3CF2CH2CH2C. H2-, CF3CH2CF2CH2CH2-, CF3CF2CF2CH2CH2-, CF3CF2CF2CF2CH2-, CF3CF2CH2CF2CH2-, CF3CF2CH2CH2CH2CH2-, CF3CF2CF 2CF2CH2CH2-, CF3CF2CH2CF2CH2CH2-, HCF2-, HCF2CH2-, HCF2CF2-, HCF2CH2CH2-, HCF2CF2CH2-, HCF2CH2CF2-, HCF2CF2C H2CH2-, HCF2CH2CF2CH2-, HCF2CF2CF2CF2-, HCF2CF2CH2CH2CH2-, HCF2CH2CF2CH2CH2-, HCF2CF2CF2CF2CH2-, HCF2CF2C F2CF2CH2CH2-, FCH2-, FCH2CH2-, FCH2CF2-, FCH2CF2CH2-, FCH2CF2CF2-, CH3CF2CH2-, CH3CF2CF2-, CH3CF2CH2CF2-, CH3 CF2CF2CF2-, CH3CH2CF2CF2-, CH3CF2CH2CF2CH2-, CH3CF2CF2CF2CH2-, CH3CF2CF2CH2CH2-, CH3CH2CF2CF2CH2-, CH3CF2C H2CF2CH2CH2-, CH3CF2CH2CF2CH2CH2-, HCFClCF2CH2-, HCF2CFClCH2-, HCF2CFClCF2CFClCH2-, HFCClCF2CFClCF2CH2-, etc.

[0368] Additionally, in R 1 In the case of a branched alkyl group having fluorine atoms, the following are preferred examples.

[0369]

Chemistry 53

[0370]

[0371]

Chemistry 54

[0372]

[0373] And so on. Among them, if it has branches such as CH3- and CF3-, the viscosity tends to be higher. Therefore, it is more preferable to have fewer (1) or zero branches.

[0374] R 2 It can be an alkylene group having 1 to 3 carbon atoms and containing fluorine atoms. R 2 It can be linear or branched. The following shows examples of the smallest structural units constituting such linear or branched alkylene groups. R 2 It consists of them individually or in combination.

[0375] (i) The smallest structural unit in a linear chain:

[0376] -CH2-, -CHF-, -CF2-, -CHCl-, -CFCl-, -CCl2-

[0377] (ii) Branched minimum structural unit:

[0378]

Transformation 55

[0379]

[0380] It should be noted that, in the above examples, from the perspective of avoiding the deHCl reaction caused by alkali and achieving greater stability, it is preferable to be composed of structural units that do not contain Cl.

[0381] In R 2 In the case of a linear structure, it is composed only of the aforementioned linear minimum structural units, preferably -CH2-, CH2CH2-, or -CF2-. From the viewpoint of further improving the solubility of the electrolyte salt, -CH2- or -CH2CH2- is more preferred.

[0382] In R 2 In the case of a branched structure, containing at least one of the aforementioned branched minimum structural units, the general formula -(CX) can be preferably exemplified. a X b )-(X a For H, F, CH3 or CF3; X b It is CH3 or CF3. Wherein, in X b In the case of CF3, X a These are units represented by H or CH3. These units, in particular, can further improve the solubility of electrolyte salts.

[0383] Preferred fluoroalkyl groups include, for example, CF3CF2-, HCF2CF2-, H2CFCF2-, CH3CF2-, CF3CH2-, CF3CF2CF2-, HCF2CF2CF2-, H2CFCF2CF2-, and CH3CF2CF2-.

[0384]

Transformation 56

[0385]

[0386]

Chemistry 57

[0387]

[0388] wait.

[0389] Among them, as Rf 2 and R 7 The fluoroalkyl group is preferably CF3-, CF3CF2-, (CF3)2CH-, CF3CH2-, C2F5CH2-, CF3CF2CH2-, HCF2CF2CH2-, CF3CFHCF2CH2-, CFH2-, or CF2H-. From the perspective of high flame retardancy, good rate capability, and good oxidation resistance, it is more preferably CF3CH2-, CF3CF2CH2-, HCF2CF2CH2-, CFH2-, or CF2H-.

[0390] In R 7 In the case of an alkyl group that does not contain fluorine atoms, it is an alkyl group having 1 to 7 carbon atoms. From the perspective of low viscosity, R... 7 The number of carbon atoms is preferably 1 to 4, more preferably 1 to 3.

[0391] Examples of alkyl groups that do not contain fluorine atoms include CH3-, CH3CH2-, (CH3)2CH-, and C3H7-. Among these, CH3- and CH3CH2- are preferred from the perspective of low viscosity and good rate capability.

[0392] The fluorine content of the aforementioned fluorinated chain carbonate is preferably 15 to 70% by mass. If the fluorine content is within the above range, the compatibility with the solvent and the solubility of the salt can be maintained. More preferably, the fluorine content is 20% by mass or more, further preferably 30% by mass or more, particularly preferably 35% by mass or more, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0393] It should be noted that in this invention, the fluorine content is determined according to the structural formula of the above-mentioned fluorinated chain carbonate, through...

[0394] {(Number of fluorine atoms × 19) / Molecular weight of fluorinated chain carbonate} × 100 (%)

[0395] The calculated value.

[0396] From the perspective of low viscosity, any one of the following compounds is preferred as the above-mentioned fluorinated chain carbonate.

[0397]

Chemistry 58

[0398]

[0399] As the above-mentioned fluorinated chain carbonate, methyl 2,2,2-trifluoroethyl carbonate (F3CH2COC(=O)OCH3) is particularly preferred.

[0400] The above-mentioned fluorinated chain carbonates can be used alone or in combination with two or more in any combination and ratio.

[0401] When the above-mentioned fluorinated chain carbonate is contained, the content of the above-mentioned fluorinated chain carbonate relative to the above-mentioned solvent is preferably 10 to 90% by volume, more preferably 40 to 85% by volume, and even more preferably 50 to 80% by volume.

[0402] The aforementioned carboxylic esters can be cyclic carboxylic esters or chain carboxylic esters.

[0403] The aforementioned cyclic carboxylic acid esters can be either unfluorinated or fluorinated cyclic carboxylic acid esters.

[0404] Examples of unfluorinated cyclic carboxylic acid esters include unfluorinated saturated cyclic carboxylic acid esters, with unfluorinated saturated cyclic carboxylic acid esters having alkylene groups having 2 to 4 carbon atoms being preferred.

[0405] Specific examples of unfluorinated saturated cyclic carboxylic acid esters having 2 to 4 carbon atoms include β-propiolactone, γ-butyrolactone, ε-caprolactone, δ-valerolactone, and α-methyl-γ-butyrolactone. Among these, γ-butyrolactone and δ-valerolactone are particularly preferred from the perspective of improving lithium-ion dissociation and loading characteristics.

[0406] The aforementioned unfluorinated saturated cyclic carboxylic esters can be used alone or in any combination and ratio of two or more.

[0407] In the case of containing the above-mentioned unfluorinated saturated cyclic carboxylic acid ester, the content of the above-mentioned unfluorinated saturated cyclic carboxylic acid ester relative to the above-mentioned solvent is preferably 0 to 90 volumes, more preferably 0.001 to 90 volumes, even more preferably 1 to 60 volumes, and particularly preferably 5 to 40 volumes.

[0408] The aforementioned chain carboxylic acid esters can be either unfluorinated or fluorinated. When the solvent contains these chain carboxylic acid esters, the increase in resistance of the electrolyte after high-temperature storage can be further suppressed.

[0409] Examples of unfluorinated chain carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, tert-butyl propionate, tert-butyl butyrate, sec-butyl propionate, sec-butyl butyrate, n-butyl butyrate, methyl pyrophosphate, ethyl pyrophosphate, tert-butyl formate, tert-butyl acetate, sec-butyl formate, sec-butyl acetate, n-hexyl tertvalate, n-propyl formate, n-propyl acetate, etc. Acetic acid n-butyl ester, pteropenic acid n-butyl ester, pteropenic acid n-octyl ester, 2-(dimethoxyphosphoryl)ethyl acetate, 2-(dimethylphosphoryl)ethyl acetate, 2-(diethoxyphosphoryl)ethyl acetate, 2-(diethylphosphoryl)ethyl acetate, isopropyl propionate, isopropyl acetate, ethyl formate, monoethyl oxalate 2-propynyl ester, isopropyl formate, isopropyl butyrate, isobutyl formate, isobutyl propionate, isobutyl butyrate, isobutyl acetate, etc.

[0410] The preferred materials are butyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate, with ethyl propionate and propyl propionate being particularly preferred.

[0411] The aforementioned unfluorinated chain carboxylic esters can be used alone or in combination with two or more in any combination and ratio.

[0412] In the case of containing the above-mentioned unfluorinated chain carboxylic acid ester, the content of the above-mentioned unfluorinated chain carboxylic acid ester relative to the above-mentioned solvent is preferably 0 to 90 volumes, more preferably 0.001 to 90 volumes, even more preferably 1 to 60 volumes, and particularly preferably 5 to 40 volumes.

[0413] The aforementioned fluorinated chain carboxylic esters are chain carboxylic esters containing fluorine atoms. Solvents containing fluorinated chain carboxylic esters can be used appropriately even at high voltages.

[0414] From the perspective of good compatibility with other solvents and good oxidation resistance, the above-mentioned fluorinated chain carboxylic acid esters are preferably those with the following general formula:

[0415] R 31 COOR 32

[0416] (where R is in the formula) 31 and R 32 Each of the above is an alkyl group having 1 to 4 carbon atoms and may contain fluorine atoms, R 31 and R 32 At least one of them contains a fluorine atom. ) represents a fluorinated chain carboxylic acid ester.

[0417] As R 31 and R 32, for example, unfluorinated alkyl groups such as methyl (-CH3), ethyl (-CH2CH3), propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), tert-butyl (-C(CH3)3), etc.; -CF3, -CF2H, -CFH2, -CF2CF3, -CF2CF2H, -CF2CFH2, -CH2CF3, -CH2CF2H, -CH2CFH2, -CF2CF2CF3, -CF2CF2CF2H, -CF2CF2CFH2, -CH2CF2CF3, -CH2CF2CF2H, -CH2CF2CFH2, -CH2CH2CF3, -CH2CH2CF2H, -CH2CH2CFH2, -CF(CF3)2, -CF(CF2H)2, -CF(CFH2)2, -CH(CF3)2, -CH(CF2H)2, -CH(CFH2)2, -CF(OCH3)CF3, -CF2CF2CF2CF3, -CF2CF2CF2CF2H, -CF2CF2CF2CFH2, -CH2CF2CF2CF3, -CH2CF2CF2CF2H, -CH2CF2CF2CFH2, -CH2CH2CF2CF3, -CH2CH2CF2CF2H, -CH2CH2CF2CFH2, -CH2CH2CH2CF3, -CH(CH2CH2CF2H, -CH2CH2CH2CFH2, -CF(CF3)CF2CF3, -CF(CF2H)CF2CF3, -CF(CFH2)CF2CF3, -CF(CF3)CF2CF2H, -CF(CF3)CF2CFH2, -CF(CF3)CH2CF3, -CF(CF3)CH2CF2H, -CF(CF3)CH2CFH2, -CH(CF3)CF2CF3, -CH(CF2H)CF2CF3, -CH(CFH2)CF2CF3, -CH(CF3)CF2CF2H, -CH(CF3)CF2CFH2, -CH(CF3)CH2CF3, -CH(CF3)CH2CF2H, -CH(CF3)CH2CFH2, -CF2CF(CF3)CF3, -CF2CF(CF2H)CF3, -CF2CF(CFH2)CF3, -CF2CF(CF3)CF2H, -CF2CF(CF3)CFH2, -CH2CF(CF3)CF3, -CH2CF(CF2H)CF3, -CH2CF(CFH2)CF3, -CH2CF(CF3)CF2H, -CH2CF(CF3)CFH2, -CH2CH(CF3)CF3, -CH2CH(CF2H)CF3, -CH2CH(CFH2)CF3, -CH2CH(CF3)CF2H,Fluoroalkyl groups such as -CH2CH(CF3)CFH2, -CF2CH(CF3)CF3, -CF2CH(CF2H)CF3, -CF2CH(CFH2)CF3, -CF2CH(CF3)CF2H, -CF2CH(CF3)CFH2, -C(CF3)3, -C(CF2H)3, and -C(CFH2)3 are preferred. Among these, methyl, ethyl, -CF3, -CF2H, -CF2CF3, -CH2CF3, -CH2CF2H, -CH2CFH2, -CH2CH2CF3, -CH2CF2CF3, -CH2CF2CF2H, and -CH2CF2CFH2 are particularly preferred due to their good compatibility with other solvents, viscosity, and oxidation resistance.

[0418] Specific examples of the aforementioned fluorinated chain carboxylic acid esters include one or more of the following substances: CF3CH2C(=O)OCH3 (methyl 3,3,3-trifluoropropionate), HCF2C(=O)OCH3 (methyl difluoroacetate), HCF2C(=O)OC2H5 (ethyl difluoroacetate), CF3C(=O)OCH2CH2CF3, CF3C(=O)OCH2C2H5, CF3C(=O)OCH2CF2CF2H (2,2,3,3-tetrafluoropropyl trifluoroacetate), CF3C(=O)OCH2CF3, CF3C(=O)OCH(CF3)2, ethyl pentafluorobutyrate, methyl pentafluoropropionate, methyl pentafluoropropionate, methyl heptafluoroisobutyrate, isopropyl trifluorobutyrate, and trifluoroethyl... Ethyl acetate, tert-butyl trifluoroacetate, n-butyl trifluoroacetate, methyl tetrafluoro-2-(methoxy)propionate, 2,2-difluoroethyl acetate, 2,2,3,3-tetrafluoropropyl acetate, CH3C(=O)OCH2CF3 (2,2,2-trifluoroethyl acetate), 2,2,3,3,4,4,4-heptafluorobutyl acetate, methyl 4,4,4-trifluorobutyrate, 4 Ethyl 4,4-trifluorobutyrate, ethyl 3,3,3-trifluoropropionate, 3,3,3-trifluoropropionate, ethyl 3-(trifluoromethyl)butyrate, methyl 2,3,3,3-tetrafluoropropionate, butyl 2,2-difluoroacetate, methyl 2,2,3,3-tetrafluoropropionate, methyl 2-(trifluoromethyl)-3,3,3-trifluoropropionate, methyl heptafluorobutyrate, etc.

[0419] Among these, considering good compatibility with other solvents and good rate capability, the preferred solvents are CF3CH2C(=O)OCH3, HCF2C(=O)OCH3, HCF2C(=O)OC2H5, CF3C(=O)OCH2C2F5, CF3C(=O)OCH2CF2CF2H, CF3C(=O)OCH2CF3, CF3C(=O)OCH(CF3)2, ethyl pentafluorobutyrate, methyl pentafluoropropionate, ethyl pentafluoropropionate, methyl heptafluoroisobutyrate, isopropyl trifluorobutyrate, ethyl trifluoroacetate, tert-butyl trifluoroacetate, n-butyl trifluoroacetate, methyl tetrafluoro-2-(methoxy)propionate, 2,2-difluoroethyl acetate, 2,2,3,3-tetrafluoropropyl acetate, CH3C(=O)OCH2CF3, 2,2,3,3-tetrafluoroethyl acetate, and 2,2,3,3-tetrafluoropropyl acetate. 3,4,4,4-Hepenobutyl ester, methyl 4,4,4-trifluorobutyrate, ethyl 4,4,4-trifluorobutyrate, ethyl 3,3,3-trifluoropropionate, 3,3,3-trifluoropropionate, ethyl 3-(trifluoromethyl)butyrate, methyl 2,3,3,3-tetrafluoropropionate, butyl 2,2-difluoroacetate, methyl 2,2,3,3-tetrafluoropropionate, 2-(trifluoromethyl) -3,3,3-methyl trifluoropropionate, methyl heptafluorobutyrate, more preferably CF3CH2C(=O)OCH3, HCF2C(=O)OCH3, HCF2C(=O)OC2H5, CH3C(=O)OCH2CF3, particularly preferably HCF2C(=O)OCH3, HCF2C(=O)OC2H5, CH3C(=O)OCF2CF3.

[0420] The above-mentioned fluorinated chain carboxylic esters can be used alone or in any combination and ratio of two or more.

[0421] When the above-mentioned fluorinated chain carboxylic acid ester is contained, the content of the above-mentioned fluorinated chain carboxylic acid ester relative to the above-mentioned solvent is preferably 10 to 90 vol%, more preferably 40 to 85 vol%, and even more preferably 50 to 80 vol%.

[0422] The solvent preferably contains at least one selected from the above-mentioned cyclic carbonate, the above-mentioned chain carbonate, and the above-mentioned chain carboxylic acid ester; more preferably, it contains the above-mentioned cyclic carbonate and at least one selected from the above-mentioned chain carbonate and the above-mentioned chain carboxylic acid ester. The above-mentioned cyclic carbonate is preferably a saturated cyclic carbonate.

[0423] Electrolytes containing the above-mentioned solvents can further improve the high-temperature storage and cycling characteristics of electrochemical devices.

[0424] When the solvent contains the cyclic carbonate and at least one selected from the chain carbonate and the chain carboxylic acid ester, it preferably contains 10 to 100% by volume, more preferably 30 to 100% by volume, and even more preferably 50 to 100% by volume of the cyclic carbonate and at least one selected from the chain carbonate and the chain carboxylic acid ester.

[0425] When the solvent contains the cyclic carbonate and at least one selected from the cyclic carbonate and the cyclic carboxylic acid ester, the volume ratio of the cyclic carbonate to at least one selected from the cyclic carbonate and the cyclic carboxylic acid ester is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 or more, even more preferably 15 / 85 or more, particularly preferably 20 / 80 or more, more preferably 90 / 10 or less, even more preferably 60 / 40 or less, and particularly preferably 50 / 50 or less.

[0426] The solvent described above preferably contains at least one selected from the above-mentioned unfluorinated saturated cyclic carbonates, the above-mentioned unfluorinated linear carbonates, and the above-mentioned unfluorinated linear carboxylic acid esters; more preferably, it contains the above-mentioned unfluorinated saturated cyclic carbonates and at least one selected from the above-mentioned unfluorinated linear carbonates and the above-mentioned unfluorinated linear carboxylic acid esters. Electrolytes containing the solvents described above are suitable for use in electrochemical devices operating at relatively low voltages.

[0427] When the solvent contains at least one of the unfluorinated saturated cyclic carbonate and the unfluorinated chain carbonate and the unfluorinated chain carboxylic acid ester, it preferably contains 5 to 100% by volume, more preferably 20 to 100% by volume, and even more preferably 30 to 100% by volume of the unfluorinated saturated cyclic carbonate and the unfluorinated chain carbonate and the unfluorinated chain carboxylic acid ester.

[0428] When the electrolyte contains the unfluorinated saturated cyclic carbonate and at least one selected from the unfluorinated chain carbonate and the unfluorinated chain carboxylic acid ester, the volume ratio of the unfluorinated saturated cyclic carbonate to at least one selected from the unfluorinated chain carbonate and the unfluorinated chain carboxylic acid ester is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 or more, even more preferably 15 / 85 or more, particularly preferably 20 / 80 or more, more preferably 90 / 10 or less, even more preferably 60 / 40 or less, and particularly preferably 50 / 50 or less.

[0429] The solvent preferably contains at least one selected from the above-mentioned fluorinated saturated cyclic carbonates, fluorinated chain carbonates, and fluorinated chain carboxylic esters; more preferably, it contains the above-mentioned fluorinated saturated cyclic carbonates and at least one selected from the above-mentioned fluorinated chain carbonates and fluorinated chain carboxylic esters. Electrolytes containing the solvents described above are suitable not only for use in electrochemical devices operating at relatively low voltages but also for use in electrochemical devices operating at relatively high voltages.

[0430] When the solvent contains the fluorinated saturated cyclic carbonate and at least one selected from the fluorinated chain carbonate and the fluorinated chain carboxylic acid ester, it preferably contains 5 to 100% by volume, more preferably 10 to 100% by volume, and even more preferably 30 to 100% by volume of the fluorinated saturated cyclic carbonate and at least one selected from the fluorinated chain carbonate and the fluorinated chain carboxylic acid ester.

[0431] When the solvent contains the fluorinated saturated cyclic carbonate and at least one selected from the fluorinated chain carbonate and the fluorinated chain carboxylic acid ester, the volume ratio of the fluorinated saturated cyclic carbonate to at least one selected from the fluorinated chain carbonate and the fluorinated chain carboxylic acid ester is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 or more, even more preferably 15 / 85 or more, particularly preferably 20 / 80 or more, more preferably 90 / 10 or less, even more preferably 60 / 40 or less, and particularly preferably 50 / 50 or less.

[0432] Alternatively, ionic liquids can also be used as the solvents mentioned above. An "ionic liquid" is a liquid composed of ions that combine organic cations and anions.

[0433] As an organic cation, there are no particular limitations; examples include imidazolium ions such as dialkylimidazolium cations and trialkylimidazolium cations; tetraalkylammonium ions; alkylpyridinium ions; dialkylpyrrolidineium ions; and dialkylpiperidineium ions.

[0434] There are no particular limitations on the anions that can act as counteracts to these organic cations. For example, PF6 anion, PF3(C2F5)3 anion, PF3(CF3)3 anion, BF4 anion, BF2(CF3)2 anion, BF3(CF3) anion, bis(oxalatoborate) anion, P(C2O4)F2 anion, Tf (trifluoromethanesulfonyl) anion, Nf (nonafluorobutanesulfonyl) anion, bis(fluorosulfonyl)imide anion, bis(trifluoromethanesulfonyl)imide anion, bis(pentafluoroethanesulfonyl)imide anion, dicyandiamide anion, and halide anions can be used.

[0435] The solvents mentioned above are preferably non-aqueous solvents, and the electrolyte of the present invention is preferably a non-aqueous electrolyte.

[0436] The content of the solvent in the electrolyte is preferably 70 to 99.999% by mass, more preferably 80% by mass or more, and even more preferably 92% by mass or less.

[0437] The electrolyte of the present invention may also contain a compound (5) represented by general formula (5).

[0438] General formula (5):

[0439]

Chemistry 59

[0440]

[0441] (where A is in the formula) a+ It can be a metal ion, hydrogen ion, or onium ion. a is an integer from 1 to 3, b is an integer from 1 to 3, p is b / a, n203 is an integer from 1 to 4, n201 is an integer from 0 to 8, n202 is 0 or 1, Z 201 Transition metals, elements in groups III, IV or V of the periodic table.

[0442] X 201 O, S, alkylene with 1-10 carbon atoms, alkyl haloidene with 1-10 carbon atoms, arylene with 6-20 carbon atoms, or arylene haloidene with 6-20 carbon atoms (alkylene, alkyl haloidene, and arylene haloidene may have substituents or heteroatoms in their structure; additionally, when n202 is 1 and n203 is 2-4, the X atoms in n203...) 201 (They can be bonded separately).

[0443] L 201 The structure can contain halogen atoms, cyano groups, alkyl groups with 1 to 10 carbon atoms, haloalkyl groups with 1 to 10 carbon atoms, aryl groups with 6 to 20 carbon atoms, and haloaryl groups with 6 to 20 carbon atoms (alkyl, haloalkyl, aryl, and haloaryl groups may have substituents and heteroatoms in their structure). Additionally, when n201 is 2 to 8, n201 L... 201 (can be bonded separately to form rings) or -Z 203 Y 203 .

[0444] Y 201 Y 202 and Z 203 Each is independently designated as O, S, or NY. 204 Hydrocarbon group or fluorinated hydrocarbon group. 203 and Y 204The elements are independently H, F, alkyl with 1 to 10 carbon atoms, haloalkyl with 1 to 10 carbon atoms, aryl with 6 to 20 carbon atoms, or haloaryl with 6 to 20 carbon atoms (alkyl, haloalkyl, aryl, and haloaryl can have substituents and heteroatoms in their structure, and multiple Y atoms are present). 203 and Y 204 In this case, they can be bonded separately to form a ring.

[0445] A a+ This refers to lithium ions, sodium ions, potassium ions, magnesium ions, calcium ions, barium ions, cesium ions, silver ions, zinc ions, copper ions, cobalt ions, iron ions, nickel ions, manganese ions, titanium ions, lead ions, chromium ions, vanadium ions, ruthenium ions, yttrium ions, lanthanide ions, actinide ions, tetrabutylammonium ions, tetraethylammonium ions, tetramethylammonium ions, triethylmethylammonium ions, triethylammonium ions, pyridinium ions, imidazolium ions, hydrogen ions, tetraethylphosphonium ions, tetramethylphosphonium ions, tetraphenylphosphonium ions, triphenylsulfonium ions, triethylsulfonium ions, etc.

[0446] In applications such as electrochemical devices, A a+ The preferred ions are lithium ions, sodium ions, magnesium ions, tetraalkylammonium ions, and hydrogen ions, with lithium ions being particularly preferred. A a+ The valence a of the cation is an integer from 1 to 3. When it is greater than 3, the lattice energy becomes larger, thus causing problems with dissolution in the solvent. Therefore, when solubility is required, a valence of 1 is more preferred. The valence b of the anion is also an integer from 1 to 3, and 1 is particularly preferred. The constant p representing the ratio of cation to anion is necessarily determined by the ratio of their valences, b / a.

[0447] Next, the ligand portion of general formula (5) will be described. In this specification, the ligand portion of general formula (5) will be related to Z. 201 The organic or inorganic parts that are bonded together are called ligands.

[0448] Z 201 Preferably, the mineral is Al, B, V, Ti, Si, Zr, Ge, Sn, Cu, Y, Zn, Ga, Nb, Ta, Bi, P, As, Sc, Hf, or Sb, and more preferably Al, B, or P.

[0449] X 201This indicates O, S, an alkylene group with 1 to 10 carbon atoms, a haloalkylene group with 1 to 10 carbon atoms, an arylene group with 6 to 20 carbon atoms, or a haloarylene group with 6 to 20 carbon atoms. These alkylene and arylene groups may have substituents or heteroatoms in their structure. Specifically, to replace the hydrogen on the alkylene and arylene groups, halogen atoms, chain-like or cyclic alkyl, aryl, alkenyl, alkoxy, aryloxy, sulfonyl, amino, cyano, carbonyl, acyl, amide, or hydroxyl groups can be used as substituents. Alternatively, the structure can be formed by introducing nitrogen, sulfur, or oxygen to replace the carbon on the alkylene and arylene groups. Furthermore, when n2O2 is 1 and n2O3 is 2 to 4, the X atoms in n2O3... 201 They can also be bonded separately. An example of this is ethylenediaminetetraacetic acid (EDTA).

[0450] L 201 This indicates a halogen atom, a cyano group, an alkyl group with 1 to 10 carbon atoms, a haloalkyl group with 1 to 10 carbon atoms, an aryl group with 6 to 20 carbon atoms, a haloaryl group with 6 to 20 carbon atoms, or -Z. 203 Y 203 (About Z) 203 Y 203 (To be discussed later). The alkyl and aryl groups here can also be combined with X. 201 Similarly, its structure can contain substituents and heteroatoms. Furthermore, when n201 is 2–8, n201 L... 201 They can also be bonded separately to form rings. As L... 201 Preferably, it contains a fluorine atom or a cyano group. This is because, in the case of a fluorine atom, the solubility and dissociation of the anionic compound salt increase, accompanied by an increase in ionic conductivity. Furthermore, it improves oxidation resistance, thereby suppressing side reactions.

[0451] Y 201 Y 202 and Z 203 Each can be represented independently as O, S, or NY. 204 Hydrocarbon group or fluorinated hydrocarbon group. 201 and Y 202 O, S or NY are preferred. 204 More preferably O. As a characteristic of compound (5), due to the presence of Y within the same ligand... 201 and Y 202 The formation of Z 201 The binding of these ligands with Z 201 The compound forms a chelate structure. Through this chelation effect, the compound's heat resistance, chemical stability, and hydrolysis resistance are improved. The constant n202 in the ligand is 0 or 1; particularly when it is 0, the chelate ring is a five-membered ring, thus exhibiting the strongest chelation effect and increased stability, making it a preferred choice.

[0452] It should be noted that, in this specification, a fluoroalkyl group is a group in which at least one hydrogen atom of a hydrocarbon group is replaced by a fluorine atom.

[0453] Y 203 and Y 204 Each of the following is independently H, F, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a haloaryl group having 6 to 20 carbon atoms. These alkyl and aryl groups may have substituents or heteroatoms in their structure. Furthermore, the presence of multiple Y atoms... 203 Or Y 204 In some cases, they can also be bonded separately to form rings.

[0454] Furthermore, the constant n203 related to the quantity of the aforementioned ligands is an integer from 1 to 4, preferably 1 or 2, more preferably 2. Additionally, the constant n201 related to the quantity of the aforementioned ligands is an integer from 0 to 8, preferably an integer from 0 to 4, more preferably 0, 2, or 4. Moreover, it is preferable that when n203 is 1, n201 is 2, and when n203 is 2, n201 is 0.

[0455] In general formula (5), alkyl, haloalkyl, aryl, haloaryl also include groups with other functional groups such as branched chains, hydroxyl groups, and ether bonds.

[0456] As compound (5), the preferred formula is:

[0457]

Transformation 60

[0458]

[0459] (where A is in the formula) a+ a, b, p, n201, Z 201 and L 201 Compounds represented as shown above, or those with the general formula:

[0460]

Chemistry 61

[0461]

[0462] (where A is in the formula) a+ a, b, p, n201, Z 201 and L 201 The compound represented as shown above.

[0463] As compounds (5), lithium oxalate-borate salts can be cited, and the following chemical formulas can be cited:

[0464]

Transformation 62

[0465]

[0466] The following chemical formula represents lithium bis(oxalate)borate (LIBOB): [Chem. 63]

[0467]

[0468] Lithium difluorooxalate borate (LIDFOB) is indicated.

[0469] As a compound (5), the following formula can also be cited:

[0470]

Chemistry 64

[0471]

[0472] Lithium difluorooxalate phosphate (LIDFOP) is represented by the following chemical formula: [Chemical Engineering 65]

[0473]

[0474] The following chemical formula represents lithium tetrafluorooxalatophosphate (LITFOP): [Chemical 66]

[0475]

[0476] Lithium bis(oxalate) difluorophosphate, etc.

[0477] In addition, specific examples of dicarboxylic acid complex salts with boron as the central element of the complex include lithium bis(malonic acid)borate, lithium difluoro(malonic acid)borate, lithium bis(methylmalonic acid)borate, lithium difluoro(methylmalonic acid)borate, lithium bis(dimethylmalonic acid)borate, and lithium difluoro(dimethylmalonic acid)borate.

[0478] Specific examples of dicarboxylic acid complex salts with phosphorus as the central element include lithium tri(oxalate) phosphate, lithium tri(malonic acid) phosphate, lithium difluorobis(malonic acid) phosphate, lithium tetrafluoro(malonic acid) phosphate, lithium tri(methylmalonic acid) phosphate, lithium difluorobis(methylmalonic acid) phosphate, lithium tetrafluoro(methylmalonic acid) phosphate, lithium tri(dimethylmalonic acid) phosphate, lithium difluorobis(dimethylmalonic acid) phosphate, and lithium tetrafluoro(dimethylmalonic acid) phosphate.

[0479] Specific examples of dicarboxylic acid complex salts with aluminum as the central element include LiAl(C2O4)2 and LiAlF2(C2O4).

[0480] Among these, lithium bis(oxalate)borate, lithium difluoro(oxalate)borate, lithium tri(oxalate)phosphate, lithium difluorobis(oxalate)phosphate, and lithium tetrafluoro(oxalate)phosphate are preferred from the perspective of easy availability and the ability to form stable film-like structures.

[0481] As compound (5), lithium bis(oxalate)borate is particularly preferred.

[0482] From the perspective of obtaining even better cycling characteristics, the content of compound (5) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, more preferably 10% by mass or less, and more preferably 3% by mass or less, relative to the solvent.

[0483] The electrolyte of the present invention preferably further contains an electrolyte salt (excluding compound (5)). As the electrolyte salt, in addition to lithium salt, ammonium salt, and metal salt, any electrolyte salt that can be used in the electrolyte, such as liquid salt (ionic liquid), inorganic polymeric salt, and organic polymeric salt, can also be used.

[0484] Lithium salts are preferred as electrolyte salts for lithium-ion secondary batteries.

[0485] As the aforementioned lithium salt, any lithium salt can be used, specifically including the following: LiPF6, LiBF4, LiClO4, LiAlF4, LiSbF6, LiTaF6, LiWF7, LiAsF6, LiAlCl4, LiI, LiBr, LiCl, and LiB. 10 Cl 10 Inorganic lithium salts such as Li2SiF6, Li2PFO3, and LiPO2F2;

[0486] Lithium tungstates such as LiWOF5;

[0487] Lithium carboxylate salts such as HCO2Li, CH3CO2Li, CH2FCO2Li, CHF2CO2Li, CF3CO2Li, CF3CH2CO2Li, CF3CF2CO2Li, CF3CF2CF2CO2Li, CF3CF2CF2CF2CO2Li, etc.

[0488] Lithium salts with S=O groups include FSO3Li, CH3SO3Li, CH2FSO3Li, CHF2SO3Li, CF3SO3Li, CF3CF2SO3Li, CF3CF2CF2SO3Li, CF3CF2CF2CF2SO3Li, lithium methyl sulfate, lithium ethyl sulfate (C2H5OSO3Li), and 2,2,2-trifluoroethyl lithium sulfate.

[0489] LiN(FCO)2, LiN(FCO)(FSO2), LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, LiN(C2F5SO2)2, lithium bis-perfluoroethanesulfonylimide, cyclic 1,2-perfluoroethane disulfonylimide, cyclic 1,3-perfluoropropane disulfonylimide, cyclic 1,2-ethane disulfonylimide, cyclic 1,3-propane disulfonylimide, cyclic 1,4-perfluorobutane disulfonylimide, LiN(CF3SO2)(FSO2), LiN(CF3SO2)(C3F7SO2), LiN(CF3SO2)(C4F9SO2), LiN(POF2)2 and other lithium imide salts;

[0490] Methyl lithium salts such as LiC(FSO2)3, LiC(CF3SO2)3, and LiC(C2F5SO2)3;

[0491] Additionally, an example can be given: LiPF a (C n F 2n+1 ) 6-a (In the formula, a is an integer from 0 to 5, and n is an integer from 1 to 6) represents salts (e.g., LiPF3(C2F5)3, LiPF3(CF3)3, LiPF3(iso-C3F7)3, LiPF5(iso-C3F7), LiPF4(CF3)2, LiPF4(C2F5)2), LiPF4(CF3SO2)2, LiPF4(C2F5SO2)2, LiBF3CF3, LiBF3C2F5, LiBF3C3F7, LiBF2(CF3)2, LiBF2(C2F5)2, LiBF2(CF3SO2)2, LiBF2(C2F5SO2)2, etc., fluorinated organic lithium salts, LiSCN, LiB(CN)4, LiB(C6H5)4, Li2(C2O4), LiP(C2O4)3, Li2B 12 F b H 12-b (b is an integer from 0 to 3) etc.

[0492] Among them, considering the effects of improved output characteristics, high-rate charge and discharge characteristics, high-temperature storage characteristics, and cycle characteristics, LiPF6, LiBF4, LiSbF6, LiTaF6, LiPO2F2, FSO3Li, CF3SO3Li, LiN(FSO2)2, and LiN(FSO2) are particularly preferred.

[0493] The lithium salts selected from LiPF6, LiN(FSO2)2, LiN(C2F5SO2)2, cyclic 1,2-perfluoroethane disulfonylimide lithium, cyclic 1,3-perfluoropropane disulfonylimide lithium, LiC(FSO2)3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiBF3CF3, LiBF3C2F5, LiPF3(CF3)3, LiPF3(C2F5)3, etc., are most preferably at least one lithium salt selected from LiPF6, LiN(FSO2)2 and LiBF4.

[0494] These electrolyte salts can be used alone or in combination of two or more. A preferred example of using two or more together is the combination of LiPF6 and LiBF4, or the combination of LiPF6 with LiPO2F2, C2H5OSO3Li, or FSO3Li, which improves high-temperature storage characteristics, loading characteristics, and cycling characteristics.

[0495] In this case, there is no limitation on the amount of LiBF4, LiPO2F2, C2H5OSO3Li or FSO3Li in the electrolyte as a whole, and it is arbitrary as long as it does not significantly impair the effect of the present invention. The amount is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0496] Another example is the combined use of inorganic and organic lithium salts, which has the effect of suppressing degradation caused by high-temperature storage. Preferred organic lithium salts include CF3SO3Li, LiN(FSO2)2, LiN(FSO2)(CF3SO2), and LiN(CF3SO2).

[0497] 2. LiN(C2F5SO2)2, cyclic 1,2-perfluoroethane disulfonylimide lithium, cyclic 1,3-perfluoropropane disulfonylimide lithium, LiC(FSO2)3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiBF3CF3, LiBF3C2F5, LiPF3(CF3)3, LiPF3(C2F5)3, etc. In this case, the proportion of the organic lithium salt relative to 100% by mass of the electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and further preferably 30% by mass or less, particularly preferably 20% by mass or less.

[0498] There are no particular limitations on the concentration of these electrolyte salts in the electrolyte, as long as it does not impair the effectiveness of the present invention. From the perspective of setting the conductivity of the electrolyte within a favorable range and ensuring good battery performance, the total molar concentration of lithium in the electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, even more preferably 0.5 mol / L or more, and preferably 3 mol / L or less, more preferably 2.5 mol / L or less, and even more preferably 2.0 mol / L or less.

[0499] If the total molar concentration of lithium is too low, the conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the conductivity may decrease due to increased viscosity, resulting in reduced battery performance.

[0500] Ammonium salts are preferred as electrolyte salts for use in double-layer capacitors.

[0501] Examples of the above-mentioned ammonium salts include (IIa) to (IIe).

[0502] (IIa) Tetraalkyl quaternary ammonium salts

[0503] The general formula (IIa) can be preferably exemplified as follows:

[0504]

Transformation 67

[0505]

[0506] (where R is in the formula) 1a R 2a R 3a and R 4a Whether the two are the same or different, they are all alkyl groups with 1 to 6 carbon atoms that may contain ether bonds; X - (represented by an anion) is a tetraalkyl quaternary ammonium salt.

[0507] In addition, from the perspective of improving oxidation resistance, it is also preferable to obtain a substance in which some or all of the hydrogen atoms of the ammonium salt are replaced by fluorine atoms and / or fluorinated alkyl groups having 1 to 4 carbon atoms.

[0508] As a specific example, the general formula (IIa-1) can be given:

[0509]

Transformation 68

[0510]

[0511] (where R is in the formula) 1a R 2a and X - Same as above; x and y may be the same or different, and are integers from 0 to 4, and x + y = 4) represent tetraalkyl quaternary ammonium salts,

[0512] General formula (IIa-2):

[0513]

Transformation 69

[0514]

[0515] (where R is in the formula) 5a It is an alkyl group having 1 to 6 carbon atoms; R 6a It is a divalent hydrocarbon group with 1 to 6 carbon atoms; R 7a It is an alkyl group having 1 to 4 carbon atoms; z is 1 or 2; X - Trialkylammonium salts containing alkyl ether groups (represented as anions).

[0516] The viscosity can be reduced by introducing alkyl ether groups.

[0517] Anion X - It can be an inorganic anion or an organic anion. An example of an inorganic anion is AlCl4. - BF4 - PF6 - AsF6 - TaF6 - I - SbF6 - Examples of organic anions include, for example, bis(oxalato)borate anion, difluoro(oxalato)borate anion, tetrafluoro(oxalato)phosphate anion, difluoro(bis(oxalato)phosphate)phosphate anion, and CF3COO. - CF3SO3 - (CF3SO2)2N - (C2F5SO2)2N - wait.

[0518] Among them, BF4 is preferred due to its good oxidation resistance and ion dissociation properties. - PF6 - AsF6 - SbF6 - .

[0519] Preferred specific examples of tetraalkyl quaternary ammonium salts include Et4NBF4, Et4NClO4, Et4NPF6, Et4NAsF6, Et4NSbF6, Et4NCF3SO3, Et4N(CF3SO2)2N, Et4NC4F9SO3, Et3MeNBF4, Et3MeNClO4, Et3MeNPF6, Et3MeNAsF6, Et3MeNSbF6, Et3MeNCF3SO3, Et3MeN(CF3SO2)2N, and Et3MeNC4F9SO3. In particular, Et4NBF4, Et4NPF6, Et4NSbF6, Et4NAsF6, Et3MeNBF4, and N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium salts are also mentioned.

[0520] (IIb) Spirocyclic bispyrrolidine onium salt

[0521] The general formula (IIb-1) can be preferably cited as an example:

[0522]

Transformation 70

[0523]

[0524] (where R is in the formula) 8a and R 9a Whether the two are the same or different, they are all alkyl groups with 1 to 4 carbon atoms; X - (where n1 is an anion; n2 is an integer from 0 to 5; n2 is an integer from 0 to 5) represents a spirocyclic bispyrrolidine onium salt.

[0525] General formula (IIb-2):

[0526]

Chemistry 71

[0527]

[0528] (where R is in the formula) 10a and R 11a Whether the two are the same or different, they are all alkyl groups with 1 to 4 carbon atoms; X - (where n is an anion; n3 is an integer from 0 to 5; n4 is an integer from 0 to 5) represents a spirocyclic bispyrrolidine onium salt, or

[0529] General formula (IIb-3):

[0530]

Chemistry 72

[0531]

[0532] (where R is in the formula) 12a and R 13a Whether the two are the same or different, they are all alkyl groups with 1 to 4 carbon atoms; X -(n is an anion; n5 is an integer from 0 to 5; n6 is an integer from 0 to 5) represents a spirocyclic bispyrrolidine onium salt.

[0533] In addition, from the perspective of improving oxidation resistance, it is preferable to obtain a substance in which some or all of the hydrogen atoms of the spirocyclic bispyrrolidine onium salt are replaced by fluorine atoms and / or fluorinated alkyl groups having 1 to 4 carbon atoms.

[0534] Anion X - The preferred specific example is the same as in (IIa). Among them, considering the high dissociation and low internal resistance at high voltage, BF4-, PF6-, (CF3SO2)2N- or (C2F5SO2)2N- are preferred.

[0535] Preferred specific examples of spirocyclic bispyrrolidine onium salts include, for example,

[0536]

Transformation 73

[0537]

[0538] wait.

[0539] This spirocyclic bispyrrolidine onium salt exhibits excellent solubility in solvents, oxidation resistance, and ionic conductivity.

[0540] (IIc) Imidazolium salts

[0541] General formula (IIc) can be exemplified:

[0542]

Chemistry 74

[0543]

[0544] (where R is in the formula) 14a and R 15a Whether the two are the same or different, they are all alkyl groups with 1 to 6 carbon atoms; X - Imidazolium salts (represented by anion).

[0545] Furthermore, from the perspective of improving oxidation resistance, it is preferable to obtain a substance in which some or all of the hydrogen atoms of the imidazolium salt are replaced by fluorine atoms and / or fluorinated alkyl groups having 1 to 4 carbon atoms.

[0546] The preferred specific example of the anion X- is the same as that in (IIa).

[0547] As a preferred specific example, for example, can be cited as follows:

[0548]

Chemistry 75

[0549]

[0550] wait.

[0551] This imidazolium salt is excellent in terms of low viscosity and good solubility.

[0552] (IId): N-alkylpyridinium salt

[0553] The general formula (IId) can be preferably exemplified as follows:

[0554]

Chemical formula 76

[0555]

[0556] (In the formula, R 16a is an alkyl group having 1 to 6 carbon atoms; X− is an anion) represents an N-alkylpyridinium salt.

[0557] In addition, from the aspect of improving oxidation resistance, a substance in which a part or all of the hydrogen atoms of the N-alkylpyridinium salt are substituted with fluorine atoms and / or fluoroalkyl groups having 1 to 4 carbon atoms is preferred.

[0558] Anion X - has the same preferred specific examples as (IIa).

[0559] As preferred specific examples, for example, there can be cited

[0560]

Chemical formula 77

[0561]

[0562] etc.

[0563] This N-alkylpyridinium salt is excellent in terms of low viscosity and good solubility.

[0564] (IIe) N,N-dialkylpyrrolidinium salt

[0565] The general formula (IIe) can be preferably exemplified as follows:

[0566]

Chemical formula 78

[0567]

[0568] (In the formula, R 17a and R 18a are the same or different and are each an alkyl group having 1 to 6 carbon atoms; X - is an anion) represents an N,N-dialkylpyrrolidinium salt.

[0569] In addition, from the aspect of improving oxidation resistance, a substance in which a part or all of the hydrogen atoms of the N,N-dialkylpyrrolidinium salt are substituted with fluorine atoms and / or fluoroalkyl groups having 1 to 4 carbon atoms is preferred.

[0570] Anion X -The preferred specific example is the same as (IIa).

[0571] As a preferred specific example, for example, can be cited as follows:

[0572]

Transformation 79

[0573]

[0574]

Chemistry 80

[0575]

[0576] wait.

[0577] This N,N-dialkylpyrrolidine onium salt exhibits excellent properties in terms of low viscosity and good solubility.

[0578] Among these ammonium salts, considering good solubility, oxidation resistance, and ion conductivity, (IIa), (IIb), and (IIc) are preferred, and more preferably...

[0579]

Chemistry 81

[0580]

[0581] (In the formula, Me is methyl; Et is ethyl; X) - x, y are the same as in equation (IIa-1).

[0582] Alternatively, lithium salts can be used as electrolyte salts for double-layer capacitors. Preferred lithium salts include, for example, LiPF6, LiBF4, LiN(FSO2)2, LiAsF6, LiSbF6, and LiN(SO2C2H5)2.

[0583] Magnesium salts can also be used to further improve capacity. Preferred magnesium salts include, for example, Mg(ClO4)2 and Mg(OOC2H5)2.

[0584] When the electrolyte salt is the aforementioned ammonium salt, the concentration is preferably 0.7 mol / L or higher. If it is lower than 0.7 mol / L, there is a risk that not only will the low-temperature characteristics deteriorate, but the initial internal resistance will also increase. The concentration of the electrolyte salt is more preferably 0.9 mol / L or higher.

[0585] From the perspective of low-temperature characteristics, the upper limit of the above concentration is preferably 2.0 mol / L or less, more preferably 1.5 mol / L or less.

[0586] When the ammonium salt is triethylmethylammonium tetrafluoroborate (TEMABF4), its concentration is preferably 0.7 to 1.5 mol / L from the perspective of excellent low-temperature characteristics.

[0587] In addition, when the spirocyclic bispyrrolidine ontium tetrafluoroborate (SBPBF4) is used, the concentration is preferably 0.7 to 2.0 mol / L.

[0588] The electrolyte of the present invention preferably further contains a solution of general formula (2):

[0589]

Chemistry 82

[0590]

[0591] (where X) 21 It is a group containing at least H or C, n21 is an integer from 1 to 3, Y 21 and Z 21 Same or different, is a group containing at least H, C, O or F, n22 is 0 or 1, Y 21 and Z 21 Compounds (2) can bond together to form rings. If the electrolyte contains compound (2), the capacity retention rate is unlikely to decrease further, and the amount of gas generated is unlikely to increase further, even when stored at high temperatures.

[0592] When n21 is 2 or 3, there are 2 or 3 X's. 21 They can be the same or different.

[0593] In the existence of multiple Y 21 and Z 21 In the case of multiple Ys 21 and Z 21 They can be the same or different.

[0594] As X 21 Preferred is -CY 21 Z 21 -(where Y is in the formula) 21 and Z 21 (as shown above) or -CY 21 =CZ 21 -(where Y is in the formula) 21 and Z 21 (As shown above) represents the group.

[0595] As Y 21 Preferably, it is selected from at least one of H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-.

[0596] As Z 21Preferably, it is selected from at least one of H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-.

[0597] Or, Y 21 and Z 21 They can bond with each other to form carbon rings or heterocycles that may contain unsaturated bonds or be aromatic. The number of carbon atoms in the ring is preferably 3 to 20.

[0598] Next, specific examples of compound (2) will be described. It should be noted that in the following examples, "analytes" refers to an anhydride obtained by replacing a portion of the illustrated anhydride structure with other structures within the scope of the present invention, such as dimers, trimers, and tetramers containing multiple anhydrides; or structural isomers with the same number of carbon atoms in the substituents but having, for example, branches, etc., substances in which the substituents are bonded to the anhydride at different sites, etc.

[0599] Specific examples of acid anhydrides that form five-membered ring structures include succinic anhydride, methylsuccinic anhydride (4-methylsuccinic anhydride), dimethylsuccinic anhydride (4,4-dimethylsuccinic anhydride, 4,5-dimethylsuccinic anhydride, etc.), 4,4,5-trimethylsuccinic anhydride, 4,4,5,5-tetramethylsuccinic anhydride, 4-vinylsuccinic anhydride, 4,5-divinylsuccinic anhydride, phenylsuccinic anhydride (4-phenylsuccinic anhydride), 4,5 -Diphenylsuccinic anhydride, 4,4-diphenylsuccinic anhydride, citraconic anhydride, maleic anhydride, methylmaleic anhydride (4-methylmaleic anhydride), 4,5-dimethylmaleic anhydride, phenylmaleic anhydride (4-phenylmaleic anhydride), 4,5-diphenylmaleic anhydride, itaconic anhydride, 5-methylitaconic anhydride, 5,5-dimethylitaconic anhydride, phthalic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, and their analogues.

[0600] Specific examples of acid anhydrides that form six-membered ring structures include cyclohexane dicarboxylic anhydrides (cyclohexane-1,2-dicarboxylic anhydrides, etc.), 4-cyclohexene-1,2-dicarboxylic anhydrides, glutaric anhydride, pentene anhydride, 2-phenylglutaric anhydride, and their analogues.

[0601] Other examples of anhydrides that form cyclic structures include 5-norbornene-2,3-dicarboxylic anhydride, cyclopentanetetracarboxylic anhydride, pyromellitic anhydride, diethylene glycol anhydride, and their analogues.

[0602] Specific examples of acid anhydrides that form cyclic structures and are replaced by halogen atoms include monofluorosuccinic anhydride (4-fluorosuccinic anhydride, etc.), 4,4-difluorosuccinic anhydride, 4,5-difluorosuccinic anhydride, 4,4,5-trifluorosuccinic anhydride, trifluoromethylsuccinic anhydride, tetrafluorosuccinic anhydride (4,4,5,5-tetrafluorosuccinic anhydride), 4-fluoromaleic anhydride, 4,5-difluoromaleic anhydride, trifluoromethylmaleic anhydride, 5-fluoroitaconic anhydride, 5,5-difluoroitaconic anhydride, etc., and their analogues.

[0603] As compound (2), preferably, glutaric anhydride, citraconic anhydride, pentene dicarboxylic anhydride, itaconic anhydride, diethylene glycol anhydride, cyclohexane dicarboxylic anhydride, cyclopentane tetracarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phenylsuccinic anhydride, 2-phenylglutaric anhydride, maleic anhydride, methylmaleic anhydride, trifluoromethylmaleic anhydride, phenylmaleic anhydride, succinic anhydride, methylsuccinic anhydride, dimethylsuccinic anhydride, trifluoromethylsuccinic anhydride, monofluorosuccinic anhydride, tetrafluorosuccinic anhydride, etc., more preferably maleic anhydride, methylmaleic anhydride, trifluoromethylmaleic anhydride, succinic anhydride, methylsuccinic anhydride, trifluoromethylsuccinic anhydride, tetrafluorosuccinic anhydride, and even more preferably maleic anhydride and succinic anhydride.

[0604] Compound (2) is preferably selected from general formula (3):

[0605]

Chemistry 83

[0606]

[0607] (where X) 31 ~X 34 Compounds (3) and general formula (4) that are identical or different (containing at least H, C, O or F groups):

[0608]

Chemical 84

[0609]

[0610] (where X) 41 and X 42 At least one of the compounds (4) that are the same or different (containing at least H, C, O or F groups).

[0611] As X 31 ~X 34 They may be the same or different, and preferably at least one is selected from alkyl, fluoroalkyl, alkenyl and fluoroalkenyl. 31 ~X 34 The number of carbon atoms is preferably 1 to 10, more preferably 1 to 3.

[0612] As X 31 ~X 34 , which are the same or different, more preferably at least one selected from H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-.

[0613] As X 41 and X 42 , which are the same or different, preferably at least one selected from alkyl, fluoroalkyl, alkenyl and fluoroalkenyl. X 41 and X 42 and X preferably have 1 to 10 carbon atoms, more preferably 1 to 3 carbon atoms.

[0614] As X 41 and X 42 , which are the same or different, more preferably at least one selected from H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-.

[0615] Compound (3) is preferably any one of the following compounds.

[0616]

Chemical Formula 85

[0617]

[0618] Compound (4) is preferably any one of the following compounds.

[0619]

Chemical Formula 86

[0620]

[0621] In order to make the above electrolyte such that the capacity retention rate is not easily further reduced and the gas generation amount is not easily further increased even when stored at high temperature, preferably 0.0001 to 15% by mass of compound (2) is contained relative to the above electrolyte. As the content of compound (2), more preferably 0.01 to 10% by mass, further preferably 0.1 to 3% by mass, and particularly preferably 0.1 to 1.0% by mass.

[0622] When both compound (3) and (4) are contained in the above electrolyte, from the viewpoint that the capacity retention rate is not easily further reduced and the gas generation amount is not easily further increased even when stored at high temperature, in the above electrolyte, preferably 0.08 to 2.50% by mass of compound (3) and 0.02 to 1.50% by mass of compound (4) are contained relative to the above electrolyte, and more preferably 0.80 to 2.50% by mass of compound (3) and 0.08 to 1.50% by mass of compound (4) are contained.

[0623] The electrolyte of the present invention may contain at least one selected from nitrile compounds represented by the following general formulas (1a), (1b), and (1c).

[0624]

Chemical formula 87

[0625]

[0626] (In the formula, R a and R b each independently represent a hydrogen atom, a cyano group (CN), a halogen atom, an alkyl group, or a group in which at least a part of the hydrogen atoms of the alkyl group are substituted by halogen atoms. n represents an integer of 1 to 10.)

[0627]

Chemical formula 88

[0628]

[0629] (In the formula, R c represents a hydrogen atom, a halogen atom, an alkyl group, a group in which at least a part of the hydrogen atoms of the alkyl group are substituted by halogen atoms, or a group represented by NC-R c1 -X c1 -(R c1 represents an alkylene group, and X c1 represents an oxygen atom or a sulfur atom.). R d and R e each independently represent a hydrogen atom, a halogen atom, an alkyl group, or a group in which at least a part of the hydrogen atoms of the alkyl group are substituted by halogen atoms. m represents an integer of 1 to 10.)

[0630]

Chemical formula 89

[0631]

[0632] (In the formula, R f , R g , R h and R i each independently represent a group containing a cyano group (CN), a hydrogen atom (H), a halogen atom, an alkyl group, or a group in which at least a part of the hydrogen atoms of the alkyl group are substituted by halogen atoms. Among them, at least one of R f , R g , R h and R i is a group containing a cyano group. l represents an integer of 1 to 3.)

[0633] Thereby, the high-temperature storage characteristics of the electrochemical device can be improved. The above nitrile compounds can be used alone or in combination of two or more in any combination and ratio.

[0634] In the above general formula (1a), R a and R b Each of the following groups is independently composed of a hydrogen atom, a cyano group (CN), a halogen atom, an alkyl group, or a group in which at least some of the hydrogen atoms of an alkyl group are replaced by halogen atoms.

[0635] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Fluorine is preferred.

[0636] The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, etc.

[0637] As a group formed by replacing at least a portion of the hydrogen atoms of an alkyl group with halogen atoms, examples of such groups are groups formed by replacing at least a portion of the hydrogen atoms of an alkyl group with halogen atoms.

[0638] In R a and R b In the case of an alkyl group or a group in which at least some of the hydrogen atoms of an alkyl group are replaced by halogen atoms, R a With R b They can bond with each other to form a ring structure (e.g., cyclohexane ring).

[0639] R a and R b Preferably, it contains hydrogen atoms or alkyl groups.

[0640] In the above general formula (1a), n is an integer from 1 to 10. When n is 2 or more, n R... a They can be completely the same, or at least partially different. (Regarding R) b Similarly, n is preferably an integer from 1 to 7, and more preferably an integer from 2 to 5.

[0641] As the nitrile compound represented by the above general formula (1a), dinitrile and trinitrile are preferred.

[0642] Specific examples of dinitriles include malononitrile, butadionitrile, glutaronitrile, adiponitrile, heptadionitrile, octadionitrile, nonadionitrile, decanadionitrile, undecanedionitrile, dodecanedionitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononitrile, methylbutadionitrile, 2,2-dimethylbutadionitrile, 2,3-dimethylbutadionitrile, 2,3,3-trimethylbutadionitrile, 2,2,3,3-tetramethylbutadionitrile, 2,3-diethyl-2,3-dimethylbutadionitrile, 2,2-diethyl-3,3-dimethylbutadionitrile, dicyclohexane-1,1-dicarboxylon, dicyclohexane-2,2-dicarboxylon, dicyclohexane-3,3-dicarboxylon, 2,5-dimethyl-2,5-hexanedicarboxylon, 2,3-diisobutyl-2,3-dimethylbutadionitrile, 2,2-diisobutyl-2,3-dimethylbutadionitrile, etc. Butyl-3,3-dimethylbutanedionitrile, 2-methylglutaronitrile, 2,3-dimethylglutaronitrile, 2,4-dimethylglutaronitrile, 2,2,3,3-tetramethylglutaronitrile, 2,2,4,4-tetramethylglutaronitrile, 2,2,3,4-tetramethylglutaronitrile, 2,3,3,4-tetramethylglutaronitrile, 1,4-dicyanopentane, 2,6-dicyanopentane, 2,7-dicyanopentane The following are examples of alkyl octane, 2,8-dicyanonane, 1,6-dicyanodecane, 1,2-dicyanobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene, 3,3'-(ethylenedioxy)dipropionitrile, 3,3'-(ethylenedithio)dipropionitrile, 3,9-bis(2-cyanoethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, butyronitrile, and phthalonitrile. Butyronitrile, glutaronitrile, and adiponitrile are particularly preferred.

[0643] In addition, specific examples of trinitriles include pentamethylenetricarbonitrile, propanetricarbonitrile, 1,3,5-hexanetricarbonitrile, 1,3,6-hexanetricarbonitrile, heptatricarbonitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, cyclohexanetricarbonitrile, tricyanoethylamine, tricyanoethoxypropane, tricyanoethylene, tri(2-cyanoethyl)amine, etc., with 1,3,6-hexanetricarbonitrile and cyclohexanetricarbonitrile being particularly preferred, and cyclohexanetricarbonitrile being the most preferred.

[0644] In the above general formula (1b), R c This refers to a group consisting of a hydrogen atom, a halogen atom, an alkyl group, a group in which at least some of the hydrogen atoms of an alkyl group are replaced by halogen atoms, or NC-R. c1 -X c1 -(R c1 Indicates alkylene, X c1 Represents an oxygen or sulfur atom. The group represented by R... d and R e Each of the following groups is independently formed by replacing hydrogen atoms, halogen atoms, alkyl groups, or at least a portion of the hydrogen atoms of an alkyl group with halogen atoms.

[0645] Groups formed by replacing at least a portion of the hydrogen atoms of a halogen atom, an alkyl group, and an alkyl group with a halogen atom, can be exemplified by the group shown in the above general formula (1a).

[0646] The above NC-R c1 -X c1 -in R c1 It is an alkylene group. Preferably, it is an alkylene group having 1 to 3 carbon atoms.

[0647] R c R d and R e Each is preferably a group consisting of a hydrogen atom, a halogen atom, an alkyl group, or a group in which at least a portion of the hydrogen atoms of an alkyl group are replaced by halogen atoms.

[0648] R c R d and R e At least one of the groups is preferably a halogen atom or an alkyl group in which at least a portion of the hydrogen atoms are replaced by halogen atoms, more preferably a fluorine atom or an alkyl group in which at least a portion of the hydrogen atoms are replaced by fluorine atoms.

[0649] In R d and R e In the case of an alkyl group or a group in which at least some of the hydrogen atoms of an alkyl group are replaced by halogen atoms, R d With R e They can also bond together to form a ring structure (e.g., cyclohexane ring).

[0650] In the above general formula (1b), m is an integer from 1 to 10. When m is 2 or more, there are m R... d They can be completely identical, or at least partially different. For R... e The same applies. m is preferably an integer from 2 to 7, and more preferably an integer from 2 to 5.

[0651] Examples of nitrile compounds represented by the general formula (1b) above include acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 3-methoxypropionitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanonitrile, cyclopentanone, cyclohexanenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitrile, 2,3-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3,3'-oxodipropionitrile, 3,3'-thiodipropionitrile, pentafluoropropionitrile, methoxyacetonitrile, benzonitrile, etc. Among these, 3,3,3-trifluoropropionitrile is particularly preferred.

[0652] In the above general formula (1c), R f R g R h and Ri Each of the following is an independent group consisting of a cyano (CN) group, a hydrogen atom, a halogen atom, an alkyl group, or a group in which at least some of the hydrogen atoms of an alkyl group are replaced by a halogen atom.

[0653] Groups formed by replacing at least a portion of the hydrogen atoms of a halogen atom, an alkyl group, and an alkyl group with a halogen atom, can be exemplified by the group shown in the above general formula (1a).

[0654] As a group containing a cyano group, in addition to the cyano group, other examples include alkyl groups in which at least some of the hydrogen atoms are replaced by cyano groups. As such alkyl groups, the alkyl groups exemplified by the above general formula (1a) can be cited.

[0655] R f R g R h and R i At least one of them is a cyano group. R is preferred. f R g R h and R i At least two of them are cyano groups, more preferably R. h and R i It is a group containing a cyano group. In R h and R i In the case where R is a group containing a cyano group, f and R g Hydrogen atoms are preferred.

[0656] In the above general formula (1c), l is an integer from 1 to 3. When l is 2 or greater, l R... f They can be completely identical, or at least partially different. For R... g The same applies. l is preferably an integer from 1 to 2.

[0657] Examples of nitrile compounds represented by the above general formula (1c) include 3-hexenedicyano, hexadienedionitrile, maleic nitrile, fumaric acid nitrile, acrylonitrile, methacrylonitrile, crotonitrile, 3-methylcrotonitrile, 2-methyl-2-butenonitrile, 2-pentenonitrile, 2-methyl-2-pentenonitrile, 3-methyl-2-pentenonitrile, and 2-hexenedicyano, with 3-hexenedicyano and hexadienedionitrile being preferred, and 3-hexenedicyano being particularly preferred.

[0658] The content of the aforementioned nitrile compounds is preferably 0.2 to 7% by mass relative to the electrolyte. This further improves the high-temperature storage characteristics and safety of the electrochemical device under high voltage. The lower limit of the total content of the aforementioned nitrile compounds is more preferably 0.3% by mass, and even more preferably 0.5% by mass. The upper limit is more preferably 5% by mass, even more preferably 2% by mass, and particularly preferably 0.5% by mass.

[0659] The electrolyte of the present invention may contain a compound having an isocyanate group (hereinafter sometimes simply referred to as "isocyanate"). There is no particular limitation on the isocyanate used; any isocyanate may be used. Examples of isocyanates include monoisocyanates, diisocyanates, and triisocyanates.

[0660] Specific examples of monoisocyanates include isocyanomethane, isocyanoethane, 1-isocyanopropane, 1-isocyanobutane, 1-isocyanopentane, 1-isocyanohexane, 1-isocyanoheptane, 1-isocyanooctane, 1-isocyanononane, 1-isocyanodecane, isocyanocyclohexane, methoxycarbonyl isocyanate, ethoxycarbonyl isocyanate, propoxycarbonyl isocyanate, butoxycarbonyl isocyanate, methoxysulfonyl isocyanate, ethoxysulfonyl isocyanate, propoxysulfonyl isocyanate, butoxysulfonyl isocyanate, fluorosulfonyl isocyanate, methyl isocyanate, butyl isocyanate, phenyl isocyanate, ethyl 2-isocyanate, ethyl 2-methacrylate, and ethyl isocyanate.

[0661] Specific examples of diisocyanates include 1,4-diisocyanate butane, 1,5-diisocyanate pentane, 1,6-diisocyanate hexane, 1,7-diisocyanate heptane, 1,8-diisocyanate octane, 1,9-diisocyanate nonane, 1,10-diisocyanate decane, 1,3-diisocyanate propylene, 1,4-diisocyanate-2-butene, and 1,4-diisocyanate-2-fluorobutane. 1,4-Diisocyanate-2,3-difluorobutane, 1,5-diisocyanate-2-pentene, 1,5-diisocyanate-2-methylpentane, 1,6-diisocyanate-2-hexene, 1,6-diisocyanate-3-hexene, 1,6-diisocyanate-3-fluorohexane, 1,6-diisocyanate-3,4-difluorohexane, toluene diisocyanate, xylene diisocyanate, toluene diisocyanate, 1,2-bis(diisocyanate) (Isocyanate-methyl)cyclohexane, 1,3-bis(isocyanate-methyl)cyclohexane, 1,4-bis(isocyanate-methyl)cyclohexane, 1,2-diisocyanate-cyclohexane, 1,3-diisocyanate-cyclohexane, 1,4-diisocyanate-cyclohexane, dicyclohexylmethane-1,1'-diisocyanate, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, dicyclohexylmethane-4 , 4'-diisocyanate, isophorone diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo[2.2.1]heptane, 2,6-bis(isocyanatomethyl)bicyclo[2.2.1]heptane, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, 1,4-phenylene diisocyanate, octamethylene diisocyanate, tetramethylene diisocyanate, etc.

[0662] Specific examples of triisocyanates include 1,6,11-triisocyanate undecane, 4-isocyanate methyl-1,8-octamethylene diisocyanate, 1,3,5-triisocyanate methylbenzene, 1,3,5-tris(6-isocyanate hexane-1-yl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 4-(isocyanate methyl)octamethylene diisocyanate.

[0663] Among them, 1,6-diisocyanate hexane, 1,3-bis(isocyanate methyl)cyclohexane, 1,3,5-tris(6-isocyanate hexane-1-yl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,4,4-trimethylhexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate are readily available industrially and can keep the manufacturing cost of the electrolyte low, so they are preferred. In addition, from a technical point of view, they can also help to form a stable film-like structure, so they are more preferred.

[0664] The isocyanate content is not particularly limited and can be arbitrary as long as it does not significantly impair the effects of the present invention. Relative to the electrolyte, it is preferably 0.001% by mass or more and 1.0% by mass or less. If the isocyanate content is above this lower limit, it can provide a sufficient improvement in the cycle characteristics of the non-aqueous electrolyte secondary battery. Furthermore, if it is below this upper limit, the initial increase in resistance of the non-aqueous electrolyte secondary battery can be avoided. The isocyanate content is more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and even more preferably 0.8% by mass or less, further preferably 0.7% by mass or less, and particularly preferably 0.6% by mass or less.

[0665] The electrolyte of the present invention may contain cyclic sulfonates. There are no particular limitations on the type of cyclic sulfonate used; any type of cyclic sulfonate may be used. Examples of cyclic sulfonates include saturated cyclic sulfonates, unsaturated cyclic sulfonates, saturated cyclic disulfonates, and unsaturated cyclic disulfonates.

[0666] Specific examples of saturated cyclic sulfonates include 1,3-propanesulfonyl lactone, 1-fluoro-1,3-propanesulfonyl lactone, 2-fluoro-1,3-propanesulfonyl lactone, 3-fluoro-1,3-propanesulfonyl lactone, 1-methyl-1,3-propanesulfonyl lactone, 2-methyl-1,3-propanesulfonyl lactone, 3-methyl-1,3-propanesulfonyl lactone, 1,3-butanesulfonyl lactone, and 1,4-butanesulfonyl lactone. Sulfolactone, 1-fluoro-1,4-butanesulfonolactone, 2-fluoro-1,4-butanesulfonolactone, 3-fluoro-1,4-butanesulfonolactone, 4-fluoro-1,4-butanesulfonolactone, 1-methyl-1,4-butanesulfonolactone, 2-methyl-1,4-butanesulfonolactone, 3-methyl-1,4-butanesulfonolactone, 4-methyl-1,4-butanesulfonolactone, 2,4-butanesulfonolactone, etc.

[0667] Specific examples of unsaturated cyclic sulfonates include 1-propen-1,3-sulfonolactone, 2-propen-1,3-sulfonolactone, 1-fluoro-1-propen-1,3-sulfonolactone, 2-fluoro-1-propen-1,3-sulfonolactone, 3-fluoro-1-propen-1,3-sulfonolactone, 1-fluoro-2-propen-1,3-sulfonolactone, 2-fluoro-2-propen-1,3-sulfonolactone, 3-fluoro-2-propen-1,3-sulfonolactone, 1-methyl-1-propen-1,3-sulfonolactone, and 2-methyl-1-propen-1,3-sulfonolactone. 3-Methyl-1-propen-1,3-sulactone, 1-Methyl-2-propen-1,3-sulactone, 2-Methyl-2-propen-1,3-sulactone, 3-Methyl-2-propen-1,3-sulactone, 1-Butene-1,4-sulactone, 2-Butene-1,4-sulactone, 3-Butene-1,4-sulactone, 1-Fluoro-1-butene-1,4-sulactone, 2-Fluoro-1-butene-1,4-sulactone, 3-Fluoro-1-butene-1,4-sulactone, 4-Fluoro-1-butene-1,4-sulactone, 1 1,4-Fluoro-2-butene-1,4-sulactone, 2-Fluoro-2-butene-1,4-sulactone, 3-Fluoro-2-butene-1,4-sulactone, 4-Fluoro-2-butene-1,4-sulactone, 1,3-Propylenesulfonyl, 1-Fluoro-3-butene-1,4-sulactone, 2-Fluoro-3-butene-1,4-sulactone, 3-Fluoro-3-butene-1,4-sulactone, 4-Fluoro-3-butene-1,4-sulactone, 1-Methyl-1-butene-1,4-sulactone, 2-Methyl-1-butene-1,4-sulactone 3-Methyl-1-butene-1,4-sulfolactone, 4-methyl-1-butene-1,4-sulfolactone, 1-methyl-2-butene-1,4-sulfolactone, 2-methyl-2-butene-1,4-sulfolactone, 3-methyl-2-butene-1,4-sulfolactone, 4-methyl-2-butene-1,4-sulfolactone, 1-methyl-3-butene-1,4-sulfolactone, 2-methyl-3-butene-1,4-sulfolactone, 3-methyl-3-butene-1,4-sulfolactone, 4-methyl-3-butene-1,4-sulfolactone, etc.

[0668] Of these, 1,3-propanesulfonyl lactone, 1-fluoro-1,3-propanesulfonyl lactone, 2-fluoro-1,3-propanesulfonyl lactone, 3-fluoro-1,3-propanesulfonyl lactone, and 1-propene-1,3-sulfonyl lactone are preferred from the perspectives of ease of acquisition and contribution to the formation of stable film-like structures. The content of the cyclic sulfonate is not particularly limited and can be arbitrary as long as it does not significantly impair the effects of the invention; it is preferably 0.001% by mass or more and 3.0% by mass or less relative to the electrolyte.

[0669] If the content of cyclic sulfonate is above the lower limit, it can provide a sufficient improvement in cycle characteristics for non-aqueous electrolyte secondary batteries. Conversely, if it is below the upper limit, it can avoid increasing the manufacturing cost of non-aqueous electrolyte secondary batteries. The content of cyclic sulfonate is more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and even more preferably 2.5% by mass or less, further preferably 2.0% by mass or less, and particularly preferably 1.8% by mass or less.

[0670] The electrolyte of the present invention may also contain polyoxyethylene with a weight average molecular weight of 2000 to 4000 and terminal -OH, -OCOOH or -COOH.

[0671] By incorporating such compounds, the stability of the electrode interface is improved, thereby enhancing the characteristics of electrochemical devices.

[0672] Examples of the aforementioned polyethylene oxides include polyethylene monool, polyethylene carboxylic acid, polyethylene glycol, polyethylene dicarboxylic acid, polyethylene triol, and polyethylene tricarboxylic acid. They can be used alone or in combination of two or more.

[0673] From the perspective of improving the characteristics of electrochemical devices, a mixture of polyoxyethylene monool and polyoxyethylene diol, and a mixture of polyoxyethylene carboxylic acid and polyoxyethylene dicarboxylic acid are preferred.

[0674] If the weight-average molecular weight of the aforementioned polyoxyethylene is too low, it may be easily oxidized and decomposed. A more preferred weight-average molecular weight is 3000–4000.

[0675] The weight-average molecular weight mentioned above can be determined by conversion of polystyrene using gel permeation chromatography (GPC).

[0676] The preferred content of the aforementioned polyoxyethylene in the electrolyte is 1×10⁻⁶. -6 ~1×10 -2 mol / kg. Excessive amounts of the aforementioned polyoxyethylene may impair the characteristics of electrochemical devices.

[0677] The preferred content of the aforementioned polyoxyethylene is 5 × 10⁻⁶. -6 Above mol / kg.

[0678] The electrolyte of the present invention may also contain fluorinated saturated cyclic carbonates, unsaturated cyclic carbonates, overcharge inhibitors, and other known additives as additives. This helps to suppress the degradation of the characteristics of electrochemical devices.

[0679] Examples of fluorinated saturated cyclic carbonates include compounds represented by the above general formula (A). Among these, fluoroethylene carbonate, difluoroethylene carbonate, monofluoromethyl ethylene carbonate, trifluoromethyl ethylene carbonate, and 2,2,3,3,3-pentafluoropropyl ethylene carbonate (4-(2,2,3,3,3-pentafluoropropyl)-[1,3]dioxapentane-2-one) are preferred. A single fluorinated saturated cyclic carbonate may be used alone, or two or more may be used in any combination and proportion.

[0680] The content of the above-mentioned fluorinated saturated cyclic carbonate relative to the above-mentioned electrolyte is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.1 to 3% by mass.

[0681] Examples of unsaturated cyclic carbonates include vinylene carbonates, ethylene carbonates substituted with substituents having aromatic rings or carbon-carbon double or triple bonds, phenyl carbonates, vinyl carbonates, allyl carbonates, and catechol carbonates.

[0682] Examples of vinylene carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-divinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, 4-fluorovinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluorovinylene carbonate, ethynyl vinylene carbonate, propynyl vinylene carbonate, methyl vinylene carbonate, and dimethyl vinylene carbonate.

[0683] Specific examples of ethylene carbonates substituted with substituents having aromatic rings or carbon-carbon double or triple bonds include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4-allyl-5-vinyl ethylene carbonate, ethynyl ethylene carbonate, 4,5-diethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate, 4-allyl-5- Ethylene carbonate, phenyl ethylene carbonate, 4,5-diphenyl ethylene carbonate, 4-phenyl-5-vinyl ethylene carbonate, 4-allyl-5-phenyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate, 4-methyl-5-allyl ethylene carbonate, 4-methylene-1,3-dioxapentane-2-one, 4,5-dioxapentane-1,3-dioxapentane-2-one, 4-methyl-5-allyl ethylene carbonate, etc.

[0684] Among these, the unsaturated cyclic carbonates are preferably vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate, 4-methyl-5-allyl ethylene carbonate, 4-allyl-5-vinyl ethylene carbonate, ethynyl ethylene carbonate, 4,5-dieethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, and 4-vinyl-5-ethynyl ethylene carbonate. Furthermore, vinylene carbonate, vinylene carbonate, and ethynyl ethylene carbonate are particularly preferred, and most preferably, because they further form a stable interfacial protective coating.

[0685] There is no particular limitation on the molecular weight of the unsaturated cyclic carbonate, and it can be any value as long as it does not significantly impair the effects of the present invention. The molecular weight is preferably 50 or more and 250 or less. Within this range, it is easy to ensure the solubility of the unsaturated cyclic carbonate relative to the electrolyte, and the effects of the present invention are easily and fully manifested. More preferably, the molecular weight of the unsaturated cyclic carbonate is 80 or more, and even more preferably, 150 or less.

[0686] There are no particular restrictions on the manufacturing method of unsaturated cyclic carbonates; any known method can be selected.

[0687] Unsaturated cyclic carbonates can be used alone or in any combination and ratio of two or more.

[0688] The content of the aforementioned unsaturated cyclic carbonate is not particularly limited, and can be arbitrary as long as it does not significantly impair the effect of the present invention. The content of the aforementioned unsaturated cyclic carbonate in 100% by mass of the electrolyte is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more. Furthermore, the aforementioned content is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less. If within the above range, the electrochemical device using the electrolyte easily exhibits a sufficient improvement in cycle characteristics, and it is also easy to avoid situations such as reduced high-temperature storage characteristics, increased gas generation, and decreased discharge capacity retention.

[0689] In addition to the unfluorinated unsaturated cyclic carbonates mentioned above, fluorinated unsaturated cyclic carbonates are also preferred as unsaturated cyclic carbonates.

[0690] Fluorinated unsaturated cyclic carbonates are cyclic carbonates containing unsaturated bonds and fluorine atoms. There are no particular restrictions on the number of fluorine atoms in a fluorinated unsaturated cyclic carbonate, as long as it is one or more. Typically, the number of fluorine atoms is six or less, preferably four or less, and most preferably one or two.

[0691] Examples of fluorounsaturated cyclic carbonates include fluoroethylene carbonate derivatives and fluoroethylene carbonate derivatives substituted with substituents having aromatic rings or carbon-carbon double bonds.

[0692] Examples of fluoroethylene carbonate derivatives include 4-fluoroethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4-allyl-5-fluoroethylene carbonate, and 4-fluoro-5-vinylethylene carbonate.

[0693] Examples of fluoroethylene carbonate derivatives substituted with substituents having aromatic rings or carbon-carbon double bonds include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allyl ethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allyl ethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allyl ethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, and 4,5-difluoro-4-vinylethylene carbonate. Fluoro-4-allyl vinyl carbonate, 4-fluoro-4,5-divinyl vinyl carbonate, 4-fluoro-4,5-diallyl vinyl carbonate, 4,5-difluoro-4,5-divinyl vinyl carbonate, 4,5-difluoro-4,5-diallyl vinyl carbonate, 4-fluoro-4-phenyl vinyl carbonate, 4-fluoro-5-phenyl vinyl carbonate, 4,4-difluoro-5-phenyl vinyl carbonate, 4,5-difluoro-4-phenyl vinyl carbonate, etc.

[0694] Among them, 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-vinylene carbonate, 4-allyl-5-fluorovinylene carbonate, 4-fluoro-4-vinylene carbonate, 4-fluoro-4-allylene carbonate, 4-fluoro-5-vinylene carbonate, 4-fluoro-5-allylene carbonate, 4,4-difluoro-4-vinylene carbonate, 4,4-difluoro-4-allylene carbonate, 4,5-difluoro-4-vinylene carbonate, 4,5-difluoro-4-allylene carbonate, 4-fluoro-4,5-divinylene carbonate, 4,5-difluoro-4,5-diallylene carbonate, 4,5-difluoro-4,5-diallylene carbonate, and 4,5-difluoro-4,5-diallylene carbonate are preferred because they form a stable interfacial protective coating.

[0695] There is no particular limitation on the molecular weight of the fluorinated unsaturated cyclic carbonate, and it can be any value as long as it does not significantly impair the effects of the invention. The molecular weight is preferably 50 or higher, and further preferably 500 or lower. Within this range, it is easy to ensure the solubility of the fluorinated unsaturated cyclic carbonate relative to the electrolyte.

[0696] There are no particular restrictions on the manufacturing method of fluorinated unsaturated cyclic carbonates; any known method can be used. A molecular weight of 100 or higher is more preferred, and even more preferred is 200 or higher.

[0697] Fluorinated unsaturated cyclic carbonates can be used alone or in combination with two or more in any proportion. Furthermore, the content of the fluorinated unsaturated cyclic carbonates is not particularly limited, and can be arbitrary as long as it does not significantly impair the effects of the invention. The content of the fluorinated unsaturated cyclic carbonates is typically 0.001% by mass or more in 100% by mass of the electrolyte, more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. Within this range, electrochemical devices using the electrolyte readily exhibit a sufficient improvement in cycle characteristics, and it is easier to avoid issues such as reduced high-temperature storage characteristics, increased gas generation, and decreased discharge capacity retention.

[0698] The electrolyte of this invention may also contain compounds with triple bonds. There is no limitation on the type of compound as long as it has one or more triple bonds within its molecule.

[0699] Specific examples of compounds with triple bonds include the following compounds.

[0700] Hydrocarbon compounds including 1-pentyne, 2-pentyne, 1-hexyne, 2-hexyne, 3-hexyne, 1-heptyne, 2-heptyne, 3-heptyne, 1-octyne, 2-octyne, 3-octyne, 4-octyne, 1-nonyne, 2-nonyne, 3-nonyne, 4-nonyne, 1-dodecyne, 2-dodecyne, 3-dodecyne, 4-dodecyne, 5-dodecyne, phenylacetylene, 1-phenyl-1-propyne, 1-phenyl-2-propyne, 1-phenyl-1-butyne, 4-phenyl-1-butyne, 4-phenyl-1-butyne, 1-phenyl-1-pentyne, 5-phenyl-1-pentyne, 1-phenyl-1-hexyne, 6-phenyl-1-hexyne, diphenylacetylene, 4-ethynyltoluene, dicyclohexylacetylene, etc.

[0701] 2-Prolynylmethyl carbonate, 2-Prolynylethyl carbonate, 2-Prolynylpropyl carbonate, 2-Prolynylbutyl carbonate, 2-Prolynylphenyl carbonate, 2-Prolynylcyclohexyl carbonate, di(2-propynyl) carbonate, 1-methyl-2-propynylmethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, 2-butynylmethyl carbonate, 3-butynylmethyl carbonate, 2-pentynylmethyl carbonate, Monocarbonates such as 3-pentynylmethyl carbonate and 4-pentynylmethyl carbonate; dicarbonates such as 2-butyn-1,4-diol dimethyl dicarbonate, 2-butyn-1,4-diol diethyl dicarbonate, 2-butyn-1,4-diol dipropyl dicarbonate, 2-butyn-1,4-diol dibutyl dicarbonate, 2-butyn-1,4-diol diphenyl dicarbonate, and 2-butyn-1,4-diol dicyclohexyl dicarbonate.

[0702] 2-Prolyne acetate, 2-Prolyne propionate, 2-Prolyne butyrate, 2-Prolyne benzoate, 2-Prolyne cyclohexanecarboxylate, 1,1-Dimethyl-2-propyne acetate, 1,1-Dimethyl-2-propyne propionate, 1,1-Dimethyl-2-propyne butyrate, 1,1-Dimethyl-2-propyne benzoate, 1,1-Dimethyl-2-propyne cyclohexanecarboxylate, 2-Butyne acetate, 3-Butyne acetate, 2-Pentyne acetate, 3-Pentyne acetate, 4-Pentyne acetate, methyl acrylate, ethyl acrylate Ester, propyl acrylate, vinyl acrylate, 2-propylene acrylate, 2-butenyl acrylate, 3-butenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, vinyl methacrylate, 2-propylene methacrylate, 2-butenyl methacrylate, 3-butenyl methacrylate, methyl 2-propynate, ethyl 2-propynate, propyl 2-propynate, vinyl 2-propynate, 2-propynate 2-propylene, 2-propynate 2-butenyl, 2-propynate 3-butenyl, 2-butenyl Methyl butyronitrile, ethyl butyronitrile, propyl butyronitrile, vinyl butyronitrile, 2-propenyl butyronitrile, 2-butyronitrile, 3-butyronitrile, methyl butyronitrile, ethyl butyronitrile, propyl butyronitrile, vinyl butyronitrile, 2-propenyl butyronitrile, 2-butenyl butyronitrile, 3-butenyl butyronitrile, methyl 2-pentyronitrile, ethyl 2-pentyronitrile, propyl 2-pentyronitrile, vinyl butyronitrile, 2-propenyl butyronitrile, 2-pentyronitrile Monocarboxylic acid esters such as 2-butenyl 2-pentynyl ester, 3-butenyl 2-pentynyl ester, methyl 3-pentynyl ester, ethyl 3-pentynyl ester, propyl 3-pentynyl ester, vinyl 3-pentynyl ester, 2-propenyl 3-pentynyl ester, 2-butenyl 3-pentynyl ester, methyl 4-pentynyl ester, ethyl 4-pentynyl ester, propyl 4-pentynyl ester, vinyl 4-pentynyl ester, 2-propenyl 4-pentynyl ester, 2-butenyl 4-pentynyl ester, 3-butenyl 4-pentynyl ester, fumarate, methyl trimethylacetate, and ethyl trimethylacetate.

[0703] 2-Butyne-1,4-diol diacetate, 2-Butyne-1,4-diol dipropionate, 2-Butyne-1,4-diol dibutyrate, 2-Butyne-1,4-diol dibenzoate, 2-Butyne-1,4-diol dicyclohexyl ester, hexahydrobenzo[1,3,2]dioxothiacyclopentane-2-oxide (1,2-cyclohexanediol, 2,2-dioxo-1,2-oxothiacyclopentane-4-ylacetate, 2,2-dioxo-1,2-oxothiacyclopentane-4-ylacetate, etc. dicarboxylic acid esters;

[0704] Monomethyl 2-propynyl oxalate, monoethyl 2-propynyl oxalate, monopropyl 2-propynyl oxalate, monoethylene 2-propynyl oxalate, monoallyl 2-propynyl oxalate, di(2-propynyl oxalate), monomethyl 2-butynyl oxalate, monoethyl 2-butynyl oxalate, monopropyl 2-butynyl oxalate, monoethylene 2-butynyl oxalate, monoallyl 2-butynyl oxalate, di(2-butynyl oxalate), monomethyl 3-butynyl oxalate, monoethyl 3-butynyl oxalate, monopropyl 3-butynyl oxalate, monoethylene 3-butynyl oxalate, monoallyl 3-butynyl oxalate, di(3-butynyl oxalate), and other oxalate diesters;

[0705] Phosphine oxides including methyl(2-propynyl)(vinyl)phosphine oxide, divinyl(2-propynyl)phosphine oxide, di(2-propynyl)(vinyl)phosphine oxide, di(2-propynyl)(2-propynyl)phosphine oxide, di(2-propynyl)(2-propynyl)phosphine oxide, di(3-butenyl)(2-propynyl)phosphine oxide, and di(2-propynyl)(3-butenyl)phosphine oxide;

[0706] 2-Propylene methyl(2-propenyl)phosphinocyanide, 2-Butenyl(methyl)phosphinocyanide, 2-Propylene bis(2-propenyl)phosphinocyanide, 2-Propylene bis(3-butenyl)phosphinocyanide, 1,1-dimethyl-2-propenyl methyl(2-propenyl)phosphinocyanide, 1,1-dimethyl-2-propenyl 2-butenyl(methyl)phosphinocyanide, 1,1-dimethyl-2-propenyl bis(2-propenyl)phosphinocyanide Phosphate esters, including 1,1-dimethyl-2-propynyl bis(3-butenyl)phosphine, 2-propynyl methyl(2-propynyl)phosphine, 3-butenyl methyl(2-propynyl)phosphine, 2-propynyl bis(2-propynyl)phosphine, 3-butenyl bis(2-propynyl)phosphine, 2-propynyl(2-propenyl)phosphine, and 3-butenyl 2-propynyl(2-propenyl)phosphine;

[0707] 2-Prolylphosphonic acid (methyl)(2-propynyl) ester, 2-Butenylphosphonic acid (methyl)(2-propynyl) ester, 2-Prolylphosphonic acid (2-propynyl)(2-propenyl) ester, 3-Butenylphosphonic acid (3-butenyl)(2-propynyl) ester, 2-Prolylphosphonic acid (1,1-dimethyl-2-propynyl)(methyl) ester, 2-Butenylphosphonic acid (1,1-dimethyl-2-propynyl)(methyl) ester, 2-Prolylphosphonic acid (1,1-dimethyl-2-propynyl)(2-propenyl) ester, 3-Butenylphosphonic acid (3-butenyl)(1,1-dimethyl-2-propynyl)(methyl) ester Phosphonates including (2-propynyl)(2-propynyl) ester, (3-butenyl)(2-propynyl) ester, (1,1-dimethyl-2-propynyl)(2-propynyl) ester, (3-butenyl)(1,1-dimethyl-2-propynyl) ester, (2-propynyl)(2-propynyl) ester, (3-butenyl)(2-propynyl) ester, (1,1-dimethyl-2-propynyl)(2-propynyl) ester, (3-butenyl)(2-propynyl) ester, (1,1-dimethyl-2-propynyl)(2-propynyl) ester, and (3-butenyl)(1,1-dimethyl-2-propynyl) ester;

[0708] Phosphate esters include (methyl)(2-propenyl)(2-propynyl) phosphate, (ethyl)(2-propenyl)(2-propynyl) phosphate, (2-butenyl)(methyl)(2-propynyl) phosphate, (2-butenyl)(ethyl)(2-propynyl) phosphate, (1,1-dimethyl-2-propynyl)(methyl)(2-propenyl) phosphate, (1,1-dimethyl-2-propynyl)(ethyl)(2-propenyl) phosphate, (2-butenyl)(1,1-dimethyl-2-propynyl)(methyl) phosphate, and (2-butenyl)(ethyl)(1,1-dimethyl-2-propynyl) phosphate.

[0709] Among them, compounds with alkynyl groups are more stable in forming a negative electrode coating in the electrolyte, and are therefore preferred.

[0710] Furthermore, from the perspective of improving preservation properties, compounds such as 2-propynyl methyl carbonate, di(2-propynyl) carbonate, 2-butyn-1,4-diol dimethyl dicarbonate, 2-propynyl acetate, 2-butyn-1,4-diol diacetate, monomethyl mono-2-propynyl oxalate, and di(2-propynyl) oxalate are particularly preferred.

[0711] The aforementioned compound with triple bonds can be used alone, or in combination with two or more compounds in any ratio. There is no limitation on the amount of the compound with triple bonds relative to the overall electrolyte of the present invention; it can be used arbitrarily as long as it does not significantly impair the effects of the present invention. Relative to the electrolyte of the present invention, it is typically contained at a concentration of 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and generally at a concentration of 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less. When the above ranges are satisfied, the output characteristics, load characteristics, cycle characteristics, high-temperature storage characteristics, and other effects are further improved.

[0712] In the electrolyte of the present invention, an anti-overcharge agent can be used to effectively suppress battery rupture and fire when the electrochemical device using the electrolyte is in an overcharged state.

[0713] Examples of anti-overfill agents include unsubstituted or alkyl-substituted terphenyl derivatives such as biphenyl, o-terphenyl, m-terphenyl, and p-terphenyl; partially hydrides of unsubstituted or alkyl-substituted terphenyl derivatives; cyclohexylbenzene, tert-butylbenzene, tert-pentylbenzene, diphenyl ether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindenhydride, cyclopentylbenzene, cyclohexylbenzene, cumene, 1,3-diisopropylbenzene, 1,4-diisopropylbenzene, tert-butylbenzene, tert-pentylbenzene, tert-hexylbenzene, and anisole; aromatic compounds such as 2-fluorobiphenyl, 4-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene, o-cyclohexylfluorobenzene, and p-cyclohexylfluorobenzene. Partially fluorinated derivatives of the above-mentioned aromatic compounds such as fluorotoluene and benzylfluoroform; fluorinated anisole compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole, 1,6-difluoroanisole, 2,6-difluoroanisole, and 3,5-difluoroanisole; aromatic acetates such as 3-propylphenylacetate, 2-ethylphenylacetate, benzylphenylacetate, methylphenylacetate, benzyl acetate, and phenethylphenylacetate; aromatic carbonates such as diphenyl carbonate and methyl phenylcarbonate; toluene derivatives such as toluene and xylene; and unsubstituted or alkyl-substituted biphenyl derivatives such as 2-methylbiphenyl, 3-methylbiphenyl, 4-methylbiphenyl, and o-cyclohexylbiphenyl. Preferably, the compounds used include biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, tert-butylbenzene, tert-amylbenzene, diphenyl ether, dibenzofuran, and other aromatic compounds, as well as diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindenium, 3-propylphenylacetate, 2-ethylphenylacetate, benzylphenylacetate, methylphenylacetate, benzyl acetate, diphenyl carbonate, methyl phenyl carbonate, etc. One of these compounds can be used alone, or two or more can be used in combination. When two or more compounds are used in combination, from the perspective of balancing overcharge prevention and high-temperature storage characteristics, a combination of cyclohexylbenzene and tert-butylbenzene or tert-amylbenzene is particularly preferred. Preferably, at least one of the following is selected from non-oxygen-containing aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, tert-butylbenzene, and tert-amylbenzene, and at least one of the following is selected from oxygen-containing aromatic compounds such as diphenyl ether and dibenzofuran.

[0714] Carboxylic anhydrides (excluding compound (2)) may also be used in the electrolyte used in this invention. Preferably, compounds represented by the following general formula (6) are preferred. There are no particular limitations on the method of manufacturing carboxylic anhydrides; any known method may be used.

[0715]

Chemistry 90

[0716]

[0717] (In general formula (6), R) 61 R 62Each can independently represent a hydrocarbon group having 1 or more but less than 15 carbon atoms that can have substituents.

[0718] R 61 R 62 There are no particular restrictions on the type of monovalent hydrocarbon group. For example, it can be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a group formed by the bonding of two aliphatic and aromatic hydrocarbon groups. The aliphatic hydrocarbon group can be a saturated hydrocarbon group or contain unsaturated bonds (carbon-carbon double or triple bonds). Furthermore, the aliphatic hydrocarbon group can be chain-like or cyclic; if chain-like, it can be straight-chain or branched. Additionally, it can be a group formed by the bonding of chains and rings. It should be noted that R... 61 and R 62 They can be the same or different.

[0719] Additionally, in R 61 R 62 When the hydrocarbon group has substituents, the type of substituent is not particularly limited as long as it does not violate the spirit of the invention. Examples include halogen atoms such as fluorine, chlorine, bromine, and iodine, with fluorine atoms being preferred. Alternatively, substituents other than halogen atoms can include ester groups, cyano groups, carbonyl groups, ether groups, and other substituents with functional groups, with cyano and carbonyl groups being preferred. 61 R 62 The hydrocarbon group may have only one such substituent or more than two. In the case of more than two substituents, these substituents may be the same or different from each other.

[0720] R 61 R 62 The number of carbon atoms in each hydrocarbon group is typically 1 or more, and typically 15 or less, preferably 12 or less, more preferably 10 or less, and even more preferably 9 or less. In R 61 With R 62 When the divalent hydrocarbon group is formed by mutual bonding, the number of carbon atoms in the divalent hydrocarbon group is generally 1 or more, and generally 15 or less, preferably 13 or less, more preferably 10 or less, and even more preferably 8 or less. Additionally, in R... 61 R 62 When the hydrocarbon group has substituents containing carbon atoms, R is preferably included in the substituents. 61 R 62 The total number of carbon atoms meets the above range.

[0721] Next, specific examples of anhydrides represented by the above general formula (6) will be described. It should be noted that in the following examples, "analogous" refers to anhydrides obtained by replacing a portion of the illustrated anhydride structure with other structures without departing from the spirit of the present invention. Examples include dimers, trimers, and tetramers containing multiple anhydrides; or structural isomers with the same number of carbon atoms in the substituents but having, for example, branches, etc., or substances in which the substituents are bonded to the anhydride at different sites.

[0722] First, the following are examples of R 61 R 62 Specific examples of the same acid anhydride.

[0723] As R 61 R 62 Specific examples of chain-alkyl anhydrides include acetic anhydride, propionic anhydride, butyric anhydride, 2-methylpropionic anhydride, 2,2-dimethylpropionic anhydride, 2-methylbutyric anhydride, 3-methylbutyric anhydride, 2,2-dimethylbutyric anhydride, 2,3-dimethylbutyric anhydride, 3,3-dimethylbutyric anhydride, 2,2,3-trimethylbutyric anhydride, 2,3,3-trimethylbutyric anhydride, 2,2,3,3-tetramethylbutyric anhydride, 2-ethylbutyric anhydride, and their analogues.

[0724] As R 61 R 62 Specific examples of cyclic alkyl anhydrides include cyclopropionic anhydride, cyclopentanionic anhydride, cyclohexanionic anhydride, and their analogues.

[0725] As R 61 R 62 Specific examples of alkenyl anhydrides include acrylic anhydride, 2-methacrylic anhydride, 3-methacrylic anhydride, 2,3-dimethylacrylic anhydride, 3,3-dimethylacrylic anhydride, 2,3,3-trimethylacrylic anhydride, 2-phenylacrylic anhydride, 3-phenylacrylic anhydride, 2,3-diphenylacrylic anhydride, 3,3-diphenylacrylic anhydride, 3-butenoic anhydride, 2-methyl-3-butenoic anhydride, 2,2-dimethyl-3-butenoic anhydride, 3-methyl-3-butenoic anhydride, 2,2-dimethyl-3-methyl-3-butenoic anhydride, 3-pentenoic anhydride, 4-pentenoic anhydride, 2-cyclopentenic anhydride, 3-cyclopentenic anhydride, 4-cyclopentenic anhydride, and their analogues.

[0726] As R 61 R 62 Specific examples of alkynyl anhydrides include propynyl anhydride, 3-phenylpropynyl anhydride, 2-butynyl anhydride, 2-pentynyl anhydride, 3-butynyl anhydride, 3-pentynyl anhydride, 4-pentynyl anhydride, and their analogues.

[0727] As R61 R 62 Specific examples of aryl anhydrides include benzoic anhydride, 4-methylbenzoic anhydride, 4-ethylbenzoic anhydride, 4-tert-butylbenzoic anhydride, 2-methylbenzoic anhydride, 2,4,6-trimethylbenzoic anhydride, 1-naphthoic anhydride, 2-naphthoic anhydride, and their analogues.

[0728] Additionally, as R 61 R 62 Examples of acid anhydrides substituted with halogen atoms are given below, mainly those substituted with fluorine atoms, but acid anhydrides obtained by replacing some or all of these fluorine atoms with chlorine, bromine, or iodine atoms are also included in the exemplified compounds.

[0729] As R 61 R 62 Examples of acid anhydrides that are chain-like alkyl groups substituted with halogen atoms include fluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, 2-fluoropropionic anhydride, 2,2-difluoropropionic anhydride, 2,3-difluoropropionic anhydride, 2,2,3-trifluoropropionic anhydride, 2,3,3-trifluoropropionic anhydride, 2,2,3,3-tetrafluoropropionic anhydride, 2,3,3,3-tetrafluoropropionic anhydride, 3-fluoropropionic anhydride, 3,3-difluoropropionic anhydride, 3,3,3-trifluoropropionic anhydride, perfluoropropionic anhydride, and their analogues.

[0730] As R 61 R 62 Examples of cyclic alkyl anhydrides that are substituted with halogen atoms include 2-fluorocyclopentanecarboxylic anhydride, 3-fluorocyclopentanecarboxylic anhydride, 4-fluorocyclopentanecarboxylic anhydride, and their analogues.

[0731] As R 61 R 62 Examples of acid anhydrides with alkenyl groups substituted with halogen atoms include 2-fluoroacrylic anhydride, 3-fluoroacrylic anhydride, 2,3-difluoroacrylic anhydride, 3,3-difluoroacrylic anhydride, 2,3,3-trifluoroacrylic anhydride, 2-(trifluoromethyl)acrylic anhydride, 3-(trifluoromethyl)acrylic anhydride, 2,3-bis(trifluoromethyl)acrylic anhydride, 2,3,3-tris(trifluoromethyl)acrylic anhydride, 2-(4-fluorophenyl)acrylic anhydride, 3-(4-fluorophenyl)acrylic anhydride, 2,3-bis(4-fluorophenyl)acrylic anhydride, 3,3-bis(4-fluorophenyl)acrylic anhydride, 2-fluoro-3-butenoic anhydride, 2,2-difluoro-3-butenoic anhydride, 3-fluoro-2-butenoic anhydride, 4-fluoro-3-butenoic anhydride, 3,4-difluoro-3-butenoic anhydride, 3,3,4-trifluoro-3-butenoic anhydride, and their analogues.

[0732] As R 61 R 62Examples of acid anhydrides with alkynyl groups substituted with halogen atoms include 3-fluoro-2-propynic anhydride, 3-(4-fluorophenyl)-2-propynic anhydride, 3-(2,3,4,5,6-pentafluorophenyl)-2-propynic anhydride, 4-fluoro-2-butynic anhydride, 4,4-difluoro-2-butynic anhydride, 4,4,4-trifluoro-2-butynic anhydride, and their analogues.

[0733] As R 61 R 62 Examples of aryl anhydrides that are substituted with halogen atoms include 4-fluorobenzoic anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, 4-trifluoromethylbenzoic anhydride, and their analogues.

[0734] As R 61 R 62 Examples of acid anhydrides with substituents that have functional groups, such as esters, nitriles, ketones, and ethers, include methoxyformic anhydride, ethoxyformic anhydride, methyloxalic anhydride, ethyloxalic anhydride, 2-cyanoacetic anhydride, 2-oxopropionic anhydride, 3-oxobutyric anhydride, 4-acetylbenzoic anhydride, methoxyacetic anhydride, 4-methoxybenzoic anhydride, and their analogues.

[0735] Next, the following are examples of R. 61 R 62 Specific examples of different acid anhydrides.

[0736] As R 61 R 62 Consider the examples given above and all combinations of their analogues. The following are representative examples.

[0737] Examples of combinations of chain alkyl groups include acetic propionic anhydride, acetic butyric anhydride, butyric propionic anhydride, and 2-methylpropionic anhydride.

[0738] Examples of combinations of chain alkyl and cyclic alkyl groups include cyclopentanoic acid anhydride, cyclohexanoic acid anhydride, and cyclopentanoic acid propionic anhydride.

[0739] Examples of combinations of chain alkyl and alkenyl groups include acetic acid acrylic anhydride, 3-methacrylic acid anhydride, 3-butenoic acid anhydride, and propionic acid anhydride.

[0740] Examples of combinations of chain alkyl groups and alkynyl groups include acetic propynyl anhydride, 2-butynyl acetic acid anhydride, 3-butynyl acetic acid anhydride, 3-phenylpropynyl acetic acid anhydride, propynyl propionate anhydride, etc.

[0741] Examples of combinations of chain alkyl groups and aryl groups include benzoic anhydride, 4-methylbenzoic anhydride, 1-naphthoic anhydride, and propionic anhydride.

[0742] Examples of combinations of chain alkyl groups and hydrocarbon groups with functional groups include fluoroacetic anhydride, trifluoroacetic anhydride, 4-fluorobenzoic anhydride, fluoroacetic propionic anhydride, alkyl oxalic anhydride, 2-cyanoacetic anhydride, 2-oxopropionic anhydride, methoxyacetic anhydride, and methoxyacetic propionic anhydride.

[0743] Examples of combinations of cyclic alkyl groups include cyclopentanoic acid and cyclohexane.

[0744] Examples of combinations of cyclic alkyl and alkenyl groups include cyclopentanoic acid anhydride, 3-methacrylic acid cyclopentanoic acid anhydride, 3-butenoic acid cyclopentanoic acid anhydride, and cyclohexylacrylic acid anhydride.

[0745] Examples of combinations of cyclic alkyl groups and alkynyl groups include propynic acid cyclopentyl carboxylic anhydride, 2-butynic acid cyclopentyl carboxylic anhydride, propynic acid cyclohexyl carboxylic anhydride, etc.

[0746] Examples of combinations of cyclic alkyl and aryl groups include cyclopentanolic anhydride benzoate, 4-methylcyclopentanolic anhydride benzoate, and cyclohexanolic anhydride benzoate.

[0747] Examples of combinations of cyclic alkyl groups and hydrocarbon groups with functional groups include cyclopentanoic anhydride fluoroacetate, trifluoroacetic anhydride cyclopentanoic acid, 2-cyanoacetic anhydride cyclopentanoic acid, methoxyacetic anhydride cyclopentanoic acid, and fluoroacetic anhydride cyclohexanoic acid.

[0748] Examples of combinations of alkenes include 2-methacrylic anhydride, 3-methacrylic anhydride, 3-butenoic anhydride, and 2-methacrylic acid-3-methacrylic anhydride.

[0749] Examples of combinations of alkenyl and alkynyl groups include propargyl anhydride of acrylic acid, 2-butargyl anhydride of acrylic acid, and 2-methacrylic acid propargyl anhydride.

[0750] Examples of combinations of alkenyl and aryl groups include benzoic anhydride acrylic acid, 4-methylbenzoic anhydride acrylic acid, and 2-methacrylic anhydride acrylic acid.

[0751] Examples of combinations of alkenyl groups and hydrocarbon groups with functional groups include fluoroacetic anhydride acrylate, trifluoroacetic anhydride acrylate, 2-cyanoacetic anhydride acrylate, methoxyacetic anhydride acrylate, and fluoroacetic anhydride 2-methacrylic acid.

[0752] Examples of combinations of alkynyl groups include 2-butynic acid anhydride, 3-butynic acid anhydride, and 2-butynic acid 3-butynic acid anhydride.

[0753] Examples of combinations of alkynyl and aryl groups include benzoic acid propargyl anhydride, 4-methylbenzoic acid propargyl anhydride, and benzoic acid 2-butargyl anhydride.

[0754] Examples of combinations of an alkynyl group and a hydrocarbon group with a functional group include propynic acid fluoroacetic anhydride, propynic acid trifluoroacetic anhydride, propynic acid 2-cyanoacetic anhydride, propynic acid methoxyacetic anhydride, and 2-butynic acid fluoroacetic anhydride.

[0755] Examples of combinations of aryl groups include 4-methylbenzoic anhydride benzoate, 1-naphthoic anhydride benzoate, and 4-methylbenzoic anhydride 1-naphthoic anhydride.

[0756] Examples of combinations of aryl groups and hydrocarbon groups with functional groups include fluoroacetic anhydride benzoate, trifluoroacetic anhydride benzoate, 2-cyanoacetic anhydride benzoate, methoxyacetic anhydride benzoate, and fluoroacetic anhydride 4-methylbenzoate.

[0757] Examples of combinations of hydrocarbon groups with functional groups include fluoroacetic acid trifluoroacetic anhydride, fluoroacetic acid 2-cyanoacetic anhydride, fluoroacetic acid methoxyacetic anhydride, and trifluoroacetic acid 2-cyanoacetic anhydride.

[0758] Among the anhydrides that form the above-mentioned chain structure, acetic anhydride, propionic anhydride, 2-methylpropionic anhydride, cyclopentanoic anhydride, cyclohexanecarboxylic anhydride, acrylic anhydride, 2-methylacrylic anhydride, 3-methylacrylic anhydride, 2,3-dimethylacrylic anhydride, 3,3-dimethylacrylic anhydride, 3-butenoic anhydride, 2-methyl-3-butenoic anhydride, propynic anhydride, 2-butynic anhydride, benzoic anhydride, 2-methylbenzoic anhydride, 4-methylbenzoic anhydride, 4-tert-butylbenzoic anhydride, trifluoroacetic anhydride, 3,3,3-trifluoroacetic anhydride, etc. Fluoropropionic anhydride, 2-(trifluoromethyl)acrylic anhydride, 2-(4-fluorophenyl)acrylic anhydride, 4-fluorobenzoic anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, methoxyformic anhydride, ethoxyformic anhydride, more preferably acrylic anhydride, 2-methacrylic anhydride, 3-methacrylic anhydride, benzoic anhydride, 2-methylbenzoic anhydride, 4-methylbenzoic anhydride, 4-tert-butylbenzoic anhydride, 4-fluorobenzoic anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, methoxyformic anhydride, ethoxyformic anhydride.

[0759] These compounds form a durable coating by appropriately bonding with lithium oxalate salts, which can particularly improve charge / discharge rate characteristics, input / output characteristics, and impedance characteristics after durability testing. In this respect, these compounds are preferred.

[0760] Furthermore, the molecular weight of the aforementioned carboxylic anhydride is not limited and can be arbitrary as long as it does not significantly impair the effects of the present invention. It is typically 90 or more, preferably 95 or more, and typically 300 or less, preferably 200 or less. If the molecular weight of the carboxylic anhydride is within the above range, the increase in electrolyte viscosity can be suppressed, and the coating density can be appropriately adjusted, thus appropriately improving durability.

[0761] Furthermore, there are no particular limitations on the manufacturing method of the aforementioned carboxylic anhydrides; any known method can be selected. The carboxylic anhydrides described above can be contained individually in the non-aqueous electrolyte of this invention, or two or more can be contained simultaneously in any combination and ratio.

[0762] Furthermore, the content of the carboxylic anhydride relative to the electrolyte of the present invention is not particularly limited, and can be arbitrary as long as it does not significantly impair the effect of the present invention. It is typically contained at a concentration of 0.01% by mass or more, preferably 0.1% by mass or more, and typically at a concentration of 5% by mass or less, preferably 3% by mass or less, relative to the electrolyte of the present invention. If the content of the carboxylic anhydride is within the above range, it is easy to exhibit improved cycle characteristics, and in addition, the reactivity is good, thus the battery characteristics are easily improved.

[0763] The electrolyte of the present invention can use other known additives. Examples of other additives include: pentane, heptane, octane, nonane, decane, cycloheptane, benzene, furan, naphthalene, 2-phenylbicyclohexane, cyclohexane, 2,4,8,10-tetraoxaspiro[5.5]undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane, and other hydrocarbon compounds;

[0764] Fluorobenzene, difluorobenzene, hexafluorobenzene, benzenefluoroform, monofluorobenzene, 1-fluoro-2-cyclohexylbenzene, 1-fluoro-4-tert-butylbenzene, 1-fluoro-3-cyclohexylbenzene, 1-fluoro-2-cyclohexylbenzene, fluorobiphenyls and other fluorinated aromatic compounds;

[0765] 1,4-Erythritan carbonate, spirobis-dimethylene carbonate, methoxyethyl-methyl carbonate, and other carbonate compounds;

[0766] Ether compounds such as dioxolane, dioxane, 2,5,8,11-tetraoxadodecane, 2,5,8,11,14-pentapentadecane, ethoxymethoxyethane, trimethoxymethane, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether (ethyl monoglyme).

[0767] Ketone compounds such as dimethyl ketone, diethyl ketone, and 3-pentanone;

[0768] 2-Allylsuccinic anhydride and other acid anhydrides;

[0769] Ester compounds such as dimethyl oxalate, diethyl oxalate, methyl ethyl oxalate, di(2-propynyl) oxalate, monomethyl mono-2-propynyl oxalate, dimethyl succinate, di(2-propynyl) glutarate, methyl formate, ethyl formate, 2-propynyl formate, 2-butyn-1,4-dimethyldicarboxylate, 2-propynyl methacrylate, and dimethyl malonate;

[0770] Acetamide compounds such as acetamide, N-methylformamide, N,N-dimethylformamide, and N,N-dimethylacetamide;

[0771] Vinyl sulfate, vinylene sulfate, vinyl sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, cyclobutene sulfone, diphenyl sulfone, N,N-dimethylmethanesulfonamide, N,N-diethylmethanesulfonamide, methyl vinyl sulfonate, ethyl vinyl sulfonate, allyl vinyl sulfonate, propargyl vinyl sulfonate, methyl allyl sulfonate, ethyl allyl sulfonate, allyl sulfonate, propargyl sulfonate, 1,2-bis(vinylsulfonyloxy)ethane, malondisulfonic anhydride, sulfonylbutyric anhydride, sulfonylbenzoic anhydride, sulfonylpropionic anhydride, ethylenedisulfonic anhydride, methanedisulfonate methylene, 2-propynyl-1-ol methanesulfonate, pentylenite sulfite, pentafluorophenyl methanesulfonate, propylene sulfate, propylene sulfite, propane sulpholactone, butenyl sulfite Butane-2,3-dimethyldimethane sulfonate, 2-butyn-1,4-dimethyldimethane sulfonate, 2-propynyl vinylsulfonate, bis(2-vinylsulfonylethyl) ether, 5-vinyl-hexahydro-1,3,2-benzodioxane-2-oxide, 2-(methanesulfonyloxy)propionic acid 2-propynyl ester, 5,5-dimethyl-1,2-oxothiacyclopentane-4-one 2,2-dioxide, 3-sulfonyl-propionic anhydride methane disulfonate trimethylene ester 2-methyltetrahydrofuran, methane disulfonate trimethylene ester, tetramethylene sulfoxide, methane disulfonate trimethylene ester, difluoroethylmethyl sulfone, divinyl sulfone, 1,2-bis(vinylsulfonyl)ethane, methyl ethanedisulfonate, ethyl ethanedisulfonate, vinyl sulfate, thiophene 1-oxide, and other sulfur-containing compounds;

[0772] Nitrogen-containing compounds such as 1-methyl-2-pyrrolidone, 1-methyl-2-piperidinone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolium ketone, N-methylsuccinimide, nitromethane, nitrobenzene, and ethylenediamine;

[0773] Trimethyl phosphite, triethyl phosphite, triphenyl phosphite, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dimethyl methylphosphonate, diethyl ethylphosphonate, dimethyl vinylphosphonate, diethyl vinylphosphonate, ethyl diethylphosphonoyl, methyl dimethylphosphinium, ethyl diethylphosphinium, trimethylphosphine oxide, triethylphosphine oxide, bis(2,2-difluoroethyl)2,2,2-trifluoroethyl phosphate, bis(2,2,3,3-tetrafluoropropyl)2,2,2- Trifluoroethyl phosphate, bis(2,2,2-trifluoroethyl)methyl phosphate, bis(2,2,2-trifluoroethyl)ethyl phosphate, bis(2,2,2-trifluoroethyl)2,2-difluoroethyl phosphate, bis(2,2,2-trifluoroethyl)2,2,3,3-tetrafluoropropyl phosphate, tributyl phosphate, tri(2,2,2-trifluoroethyl) phosphate, tri(1,1,1,3,3,3-hexafluoropropane-2-yl) phosphate, trioctyl phosphate, 2-phenylphenyldimethyl phosphate Ester, 2-phenylphenyl diethyl phosphate, (2,2,2-trifluoroethyl)(2,2,3,3-tetrafluoropropyl)methyl phosphate, methyl 2-(dimethoxyphosphoryl)acetate, methyl 2-(dimethylphosphoryl)acetate, methyl 2-(diethoxyphosphoryl)acetate, methyl 2-(diethylphosphoryl)acetate, methyl methylene bisphosphonate, ethyl methylene bisphosphonate, methyl ethyl ethyl bisphosphonate, ethyl ethyl bisphosphonate, methyl butyl bisphosphonate, 2- Phosphorus-containing compounds include (dimethoxyphosphoryl)acetic acid 2-propynyl ester, 2-(dimethylphosphoryl)acetic acid 2-propynyl ester, 2-(diethoxyphosphoryl)acetic acid 2-propynyl ester, 2-(diethylphosphoryl)acetic acid 2-propynyl ester, tri(trimethylsilyl) phosphate, tri(triethylsilyl) phosphate, tri(trimethoxysilyl) phosphate, tri(trimethylsilyl) phosphite, tri(triethylsilyl) phosphite, tri(trimethoxysilyl) phosphite, trimethylsilyl polyphosphate, etc.

[0774] Boron-containing compounds such as tris(trimethylsilyl) borate and tris(trimethoxysilyl) borate;

[0775] Silane compounds such as dimethylammonium trimethylaluminum silicate, diethanoltriethylaluminum silicate, dipropanoltriethylaluminum silicate, dibutanoltrimethylaluminum silicate, dibutanoltriethylaluminum silicate, tetra(trimethylsiloxy)titanium, tetra(triethylsiloxy)titanium, and tetramethylsilane;

[0776] These additives can be used individually or in combination of two or more. Adding these additives can improve capacity retention and cycling characteristics after high-temperature storage.

[0777] As other additives mentioned above, phosphorus-containing compounds are preferred, and tris(trimethylsilyl) phosphate or tris(trimethylsilyl) phosphite are particularly preferred.

[0778] The amount of other additives is not particularly limited, and can be arbitrary as long as it does not significantly impair the effect of the present invention. The amount of other additives in 100% by mass of the electrolyte is preferably 0.01% by mass or more, and further preferably 5% by mass or less. Within this range, the effects of the other additives are easily and fully manifested, and it is also easy to avoid the degradation of battery characteristics such as high-load discharge characteristics. The amount of other additives is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, further preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0779] The electrolyte of the present invention may further contain cyclic and chain carboxylic esters, ether compounds, nitrogen-containing compounds, boron-containing compounds, organosilicon compounds, non-flammable (flame retardant) agents, surfactants, high dielectric constant additives, cycling and rate performance improvers, sulfone compounds, etc., as additives, without impairing the effects of the present invention.

[0780] Examples of cyclic carboxylic acid esters include those with a total carbon number of 3 to 12 in their structural formula. Specifically, examples include γ-butyrolactone, γ-valerolactone, γ-caprolactone, ε-caprolactone, and 3-methyl-γ-butyrolactone. Among these, γ-butyrolactone is particularly preferred because it can improve the degree of lithium-ion dissociation, thereby enhancing the characteristics of electrochemical devices.

[0781] The amount of the cyclic carboxylic acid ester used as an additive is preferably 0.1% by mass or more, more preferably 1% by mass or more, in 100% by mass of the solvent. Within this range, the conductivity of the electrolyte can be improved, making it easier to enhance the high-current discharge characteristics of the electrochemical device. Furthermore, the amount of the cyclic carboxylic acid ester is preferably 10% by mass or less, more preferably 5% by mass or less. By setting this upper limit, the viscosity of the electrolyte is kept within an appropriate range, preventing a decrease in conductivity, suppressing an increase in negative electrode resistance, and making it easier to maintain the high-current discharge characteristics of the electrochemical device within a favorable range.

[0782] Furthermore, fluorocyclic carboxylic acid esters (fluorinated lactones) are also preferably used as the aforementioned cyclic carboxylic acid esters. Examples of fluorinated lactones include the following formula (C):

[0783]

Chemistry 91

[0784]

[0785] (where X) 15 ~X 20 Whether identical or different, all are -H, -F, -Cl, -CH3, or fluoroalkyl; wherein, X 15 ~X 20 Fluorinated lactones are defined as having at least one fluoroalkyl group in their names.

[0786] As X 15 ~X 20 The fluoroalkyl groups in the fluoroalkyl group include, for example, -CFH2, -CF2H, -CF3, -CH2CF3, -CF2CF3, -CH2CF2CF3, -CF(CF3)2, etc. From the perspective of high oxidation resistance and improved safety, -CH2CF3 or -CH2CF2CF3 is preferred.

[0787] If X 15 ~X 20 If at least one of the atoms is a fluoroalkyl group, then -H, -F, -Cl, -CH3, or a fluoroalkyl group may be used only in X. 15 ~X 20 It can be substituted at one position, or at multiple positions. From the perspective of good solubility of the electrolyte salt, 1 to 3 positions are preferred, and 1 to 2 positions are more preferred.

[0788] The substitution position of the fluoroalkyl group is not particularly limited; from the perspective of good synthetic yield, X 17 and / or X 18 Especially X 17 or X 18 It is a fluoroalkyl group, preferably -CH2CF3 or -CH2CF2CF3. X other than fluoroalkyl groups 15 ~X 20 The atom is -H, -F, -Cl or CH3, and -H is preferred, especially considering the good solubility of the electrolyte salt.

[0789] In addition to the compounds represented by the above formula, other examples of fluorinated lactones, such as those represented by formula (D), can also be cited:

[0790]

Chemistry 92

[0791]

[0792] (In the formula, either A or B is CX) 226 X 227 (X 226 and X 227 Whether the two are the same or different, both are -H, -F, -Cl, -CF3, -CH3, or hydrogen atoms can be replaced by halogen atoms, and the chain can contain heteroatoms in alkyl groups; the other is an oxygen atom; Rf 12 It can be a fluoroalkyl or fluoroalkoxy group that has an ether bond; X 221 and X 222 Whether the values ​​are the same or different, they are all -H, -F, -Cl, -CF3, or CH3; X 223 ~X 225Whether the two are the same or different, they are all -H, -F, -Cl, or hydrogen atoms can be replaced by halogen atoms, and the chain can contain heteroatoms of alkyl groups; n = 0 or 1).

[0793] From the perspectives of ease of synthesis and good chemical stability, the following formula (E) is preferred as the fluorinated lactone represented by formula (D):

[0794]

Chemistry 93

[0795]

[0796] (where A, B, and Rf are in the formula) 12 X 221 X 222 and X 223 Same as equation (D)

[0797] The 5-membered ring structure shown, further, based on the combination of A and B, includes the following equation (F):

[0798]

Chemical 94

[0799]

[0800] (where Rf) 12 X 221 X 222 X 223 X 226 and X 227 Same as equation (D)

[0801] The fluorinated lactones represented are those of the following formula (G):

[0802]

Chemical 95

[0803]

[0804] (where Rf) 12 X 221 X 222 X 223 X 226 and X 227 Same as equation (D)

[0805] The term refers to fluorinated lactones.

[0806] From the perspective of particularly leveraging excellent properties such as high dielectric constant and high voltage withstand capability, and from the perspective of improving the properties of the electrolyte in this invention in terms of good solubility of electrolyte salt and reduction of internal resistance, examples can be cited.

[0807]

Chemistry 96

[0808]

[0809] wait.

[0810] By using fluorinated cyclic carboxylic esters, effects such as improved ionic conductivity, enhanced safety, and increased stability at high temperatures can be achieved.

[0811] Examples of the aforementioned chain-like carboxylic acid esters include those with a total carbon number of 3 to 7 in their structural formula. Specifically, examples include methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isobutyl propionate, n-butyl propionate, methyl butyrate, isobutyl propionate, tert-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, n-propyl isobutyrate, and isopropyl isobutyrate.

[0812] From the perspective of improving ionic conductivity due to reduced viscosity, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, methyl butyrate, and ethyl butyrate are preferred.

[0813] The preferred ether compounds are chain ethers with 2 to 10 carbon atoms and cyclic ethers with 3 to 6 carbon atoms.

[0814] Examples of chain ethers with 2 to 10 carbon atoms include dimethyl ether, diethyl ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, diethoxymethane, dimethoxyethane, methoxyethoxyethane, diethoxyethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol, diethylene glycol dimethyl ether, pentaethylene glycol, triethylene glycol dimethyl ether, triethylene glycol, tetraethylene glycol, tetraethylene glycol dimethyl ether, and diisopropyl ether.

[0815] In addition, fluoroethers are also preferred as the ether compounds mentioned above.

[0816] Examples of the above-mentioned fluoroethers include the following general formula (I):

[0817] Rf 3 -O-Rf 4 (I)

[0818] (where Rf) 3 and Rf 4 Whether the groups are the same or different, they are alkyl groups with 1 to 10 carbon atoms or fluoroalkyl groups with 1 to 10 carbon atoms. Among them, Rf... 3 and Rf 4 At least one of them is a fluoroalkyl group. ) represents a fluoroether (I).

[0819] By including fluorinated ethers (I), the flame retardancy of the electrolyte is improved, as well as its stability and safety under high temperature and high voltage.

[0820] In the above general formula (I), Rf 3 and Rf 4 At least one of the components can be a fluoroalkyl group with 1 to 10 carbon atoms. From the perspective of further improving the flame retardancy and stability and safety of the electrolyte under high temperature and high voltage, Rf is preferred. 3 and Rf 4 It is also a fluoroalkyl group with 1 to 10 carbon atoms. In this case, Rf 3 and Rf 4 They can be the same, or they can be different from each other.

[0821] Among them, Rf is more preferred. 3 and Rf 4 Same or different, Rf 3 It is a fluoroalkyl group with 3 to 6 carbon atoms and Rf 4 It is a fluoroalkyl group with 2 to 6 carbon atoms.

[0822] If Rf 3 and Rf 4 If the total number of carbon atoms is too low, the boiling point of the fluoroether becomes too low. Additionally, if Rf... 3 or Rf 4 An excessive number of carbon atoms reduces the solubility of the electrolyte salt and negatively impacts its compatibility with other solvents. Furthermore, the increased viscosity leads to a decrease in rate capability. (In Rf) 3 The number of carbon atoms is 3 or 4, Rf 4 Having 2 or 3 carbon atoms is advantageous in terms of excellent boiling point and rate capability.

[0823] The fluorine content of the aforementioned fluorinated ether (I) is preferably 40-75% by mass. When the fluorine content is within this range, the balance between non-flammability and compatibility is particularly excellent. In addition, it is also preferred from the perspective of good oxidation resistance and safety.

[0824] The lower limit of the fluorine content is more preferably 45% by mass, further preferably 50% by mass, and particularly preferably 55% by mass. The upper limit is more preferably 70% by mass, and further preferably 66% by mass.

[0825] In addition, the fluorine content of fluorinated ether (I) is calculated based on the structural formula of fluorinated ether (I) by {(number of fluorine atoms × 19) / molecular weight of fluorinated ether (I)} × 100 (%).

[0826] As Rf 3Examples include CF3CF2CH2-, CF3CFHCF2-, HCF2CF2CF2-, HCF2CF2CH2-, CF3CF2CH2CH2-, CF3CFHCF2CH2-, HCF2CF2CF2CF2-, HCF2CF2CF2CH2-, HCF2CF2CH2CH2-, and HCF2CF(CF3)CH2-. Additionally, as Rf... 4 Examples include -CH2CF2CF3, -CF2CFHCF3, -CF2CF2CF2H, -CH2CF2CF2H, -CH2CH2CF2CF3, -CH2CF2CFHCF3, -CF2CF2CF2CF2H, -CH2CF2CF2CF2H, -CH2CH2CF2CF2H, -CH2CF(CF3)CF2H, -CF2CF2H, -CH2CF2H, -CF2CH3, etc.

[0827] Specific examples of the aforementioned fluorinated ethers (I) include HCF2CF2CH2OCF2CF2H, CF3CF2CH2OCF2CF2H, HCF2CF2CH2OCF2CFHCF3, CF3CF2CH2OCF2CFHCF3, and C6F. 13 OCH3, C6F 13 OC2H5, C8F 17 OCH3, C8F 17 OC2H5, CF3CFHCF2CH(CH3)OCF2CFHCF3, HCF2CF2OCH(C2H5)2, HCF2CF2OC4H9, HCF2CF2OCH2CH(C2H5)2, HCF2CF2OCH2CH(CH3)2, etc.

[0828] Among them, substances containing HCF2- or CF3CFH- at one or both ends exhibit excellent polarizability and can form fluorinated ethers (I) with high boiling points. The boiling point of the fluorinated ether (I) is preferably 67 to 120°C. More preferably, it is 80°C or higher, and even more preferably, it is 90°C or higher.

[0829] Examples of such fluorinated ethers (I) include one or more of the following: CF3CH2OCF2CFHCF3, CF3CF2CH2OCF2CFHCF3, HCF2CF2CH2OCF2CFHCF3, HCF2CF2CH2OCH2CF2CF2H, CF3CFHCF2CH2OCF2CFHCF3, HCF2CF2CH2OCF2CF2H, and CF3CF2CH2OCF2CF2H.

[0830] From the perspective of advantages in terms of high boiling point, good compatibility with other solvents, and good solubility of electrolyte salts, it is preferable to select at least one of HCF2CF2CH2OCF2CFHCF3 (boiling point 106°C), CF3CF2CH2OCF2CFHCF3 (boiling point 82°C), HCF2CF2CH2OCF2CF2H (boiling point 92°C), and CF3CF2CH2OCF2CF2H (boiling point 68°C), and more preferably at least one of HCF2CF2CH2OCF2CFHCF3 (boiling point 106°C) and HCF2CF2CH2OCF2CF2H (boiling point 92°C).

[0831] Examples of cyclic ethers with 3 to 6 carbon atoms include 1,2-dioxane, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1,4-dioxane, trioxymethylene, 2-methyl-1,3-dioxolane, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 2-(trifluoroethyl)dioxolane, 2,2-bis(trifluoromethyl)-1,3-dioxolane, and their fluorinated compounds. Among them, from the perspective of high solubility for lithium ions and improved ion dissociation, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, and crown ether are preferred; from the perspective of low viscosity and high ion conductivity, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are particularly preferred.

[0832] Examples of nitrogen-containing compounds include nitriles, fluoronitriles, carboxylic amides, fluorocarboxylic amides, sulfonamides, fluorosulfonamides, acetamides, and formamides. Additionally, 1-methyl-2-pyrrolidone, 1-methyl-2-piperidinone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolium ketone, and N-methylsuccinimide may also be used. Nitrile compounds represented by the above general formulas (1a), (1b), and (1c) are not included among the nitrogen-containing compounds described above.

[0833] Examples of boron-containing compounds include, for example, trimethyl borate, triethyl borate and other borate esters, borate ethers and alkylboranes.

[0834] Examples of the aforementioned organosilicon compounds include (CH3)4-Si, (CH3)3-Si-Si(CH3)3, and silicone oil.

[0835] Examples of non-flammable (flame retardant) agents include phosphate esters and phosphazene compounds. Examples of phosphate esters include fluoroalkyl phosphate esters, non-fluorinated alkyl phosphate esters, and aryl phosphate esters. Among these, fluoroalkyl phosphate esters are preferred from the perspective that a small amount is sufficient to achieve a non-flammable effect.

[0836] Examples of the aforementioned phosphazene compounds include methoxypentafluorocyclotriphosphazene, phenoxypentafluorocyclotriphosphazene, dimethylaminopentafluorocyclotriphosphazene, diethylaminopentafluorocyclotriphosphazene, ethoxypentafluorocyclotriphosphazene, and ethoxyheptafluorocyclotetraphosphazene.

[0837] Specifically, examples of the aforementioned fluorinated alkyl phosphates include the fluorinated dialkyl phosphates disclosed in Japanese Patent Application Publication No. 11-233141, the cyclic alkyl phosphates disclosed in Japanese Patent Application Publication No. 11-283669, and fluorinated trialkyl phosphates.

[0838] As the above-mentioned non-flammable (flame retardant) agent, (CH3O)3P=O, (CF3CH2O)3P=O, (HCF2CH2O)3P=O, (CF3CF2CH2)3P=O, (HCF2CF2CH2)3P=O, etc. are preferred.

[0839] The surfactant can be any of the following: cationic surfactant, anionic surfactant, nonionic surfactant, or amphoteric surfactant. However, from the perspective of good cycling characteristics and rate capability, a surfactant containing fluorine atoms is preferred.

[0840] As a surfactant containing fluorine atoms, the following formula (30) is preferred, for example:

[0841] Rf 5 COO - M + (30)

[0842] (where Rf) 5 It is a fluorinated alkyl group with 3 to 10 carbon atoms that may contain ether bonds; M + For Li + Na + K + or NHR'3 + (Whether R' is the same or different, it is either H or an alkyl group with 1 to 3 carbon atoms)

[0843] The fluorinated carboxylate, or the following formula (40):

[0844] Rf 6 SO3 - M + (40)

[0845] (where Rf) 6 It is a fluorinated alkyl group with 3 to 10 carbon atoms that may contain ether bonds; M + For Li + Na + K+ or NHR'3 + (Whether R' is the same or different, it is either H or an alkyl group with 1 to 3 carbon atoms)

[0846] This refers to fluorosulfonates, etc.

[0847] From the perspective of reducing the surface tension of the electrolyte without reducing the charge-discharge cycle characteristics, the content of the above-mentioned surfactant in the electrolyte is preferably 0.01 to 2% by mass.

[0848] Examples of additives that can be used to increase the dielectric constant include sulfolane, methyl sulfolane, γ-butyrolactone, and γ-valerolactone.

[0849] Examples of agents that improve the aforementioned cycling and rate characteristics include methyl acetate, ethyl acetate, tetrahydrofuran, and 1,4-dioxane.

[0850] In addition, the electrolyte of the present invention can also be combined with polymer materials to form a gel-like (plasticized) gel electrolyte.

[0851] Examples of such polymeric materials include conventionally known polyoxyethylene, polyoxypropylene, and their modified forms (Japanese Patent Application Publication No. 8-222270, Japanese Patent Application Publication No. 2002-100405); polyacrylate polymers, polyacrylonitrile, polyvinylidene fluoride, and fluoropolymers such as vinylidene fluoride-hexafluoropropylene copolymers (Japanese Patent Application Publication No. 4-506726, Japanese Patent Application Publication No. 8-507407, Japanese Patent Application Publication No. 10-294131); and complexes of these fluoropolymers with hydrocarbon resins (Japanese Patent Application Publication No. 11-35765, Japanese Patent Application Publication No. 11-86630). Polyvinylidene fluoride and vinylidene fluoride-hexafluoropropylene copolymers are particularly preferred as polymeric materials for gel electrolytes.

[0852] Furthermore, the electrolyte of the present invention may also contain the ion-conducting compound described in Japanese Patent Application No. 2004-301934.

[0853] The ion-conducting compound is an amorphous fluorinated polyether compound with fluorinated groups on its side chains, represented by formula (101):

[0854] A-(D)-B(101)

[0855] [In the formula, D represents equation (201):]

[0856] -(D1) n -(FAE) m -(AE) p -(Y)q -(201)

[0857] (In the formula, D1 is an ether unit with a fluorinated ether group in the side chain, represented by formula (2a):)

[0858]

Chemistry 97

[0859]

[0860] (In the formula, Rf is a fluorinated ether group that can have crosslinking functional groups; R 10 (The group or bond that bonds Rf to the main chain);

[0861] FAE is an ether unit with a fluoroalkyl side chain, represented by formula (2b):

[0862]

Chem.98

[0863]

[0864] (In the formula, Rfa is a hydrogen atom, and a fluoroalkyl group that may have cross-linking functional groups; R 11 (The group or bond that bonds Rfa to the main chain);

[0865] AE represents the ether unit as shown in equation (2c):

[0866]

Chem.99

[0867]

[0868] (where R is in the formula) 13 It can be a hydrogen atom, an alkyl group that may have a crosslinking functional group, an aliphatic cyclic hydrocarbon group that may have a crosslinking functional group, or an aromatic hydrocarbon group that may have a crosslinking functional group; R 12 To make R 13 (Groups or bonds bonded to the main chain);

[0869] Y is a unit containing at least one of the formulas (2d-1) to (2d-3):

[0870]

Chemistry 100

[0871]

[0872] n is an integer from 0 to 200; m is an integer from 0 to 200; p is an integer from 0 to 10000; q is an integer from 1 to 100; where n+m is not 0, and the bonding order of D1, FAE, AE and Y is not specific.

[0873] A and B may be the same or different, and can be a hydrogen atom, an alkyl group that may contain fluorine atoms and / or cross-linking functional groups, a phenyl group that may contain fluorine atoms and / or cross-linking functional groups, a -COOH group, a -OR group (R is a hydrogen atom or an alkyl group that may contain fluorine atoms and / or cross-linking functional groups), an ester group, or a carbonate group (wherein, if the terminal of D is an oxygen atom, it is not a -COOH group, a -OR group, an ester group, or a carbonate group)).

[0874] The electrolyte of the present invention may contain sulfone compounds. Preferably, cyclic sulfones with 3 to 6 carbon atoms and chain sulfones with 2 to 6 carbon atoms are sulfones. The number of sulfonyl groups in one molecule is preferably 1 or 2.

[0875] Examples of cyclic sulfones include monosulfone compounds such as trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones; and disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones. From the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, and hexamethylene disulfones are more preferred, and tetramethylene sulfones (sulfolane) are particularly preferred.

[0876] As sulfolane, sulfolane and / or sulfolane derivatives are preferred (hereinafter, including sulfolane, it is sometimes abbreviated as "sulfolane"). As sulfolane derivatives, sulfolane derivatives in which one or more of the hydrogen atoms bonded to the carbon atoms constituting the sulfolane ring are replaced by fluorine atoms or alkyl groups are preferred.

[0877] Among these, 2-methylcyclobutane sulfone, 3-methylcyclobutane sulfone, 2-fluorocyclobutane sulfone, 3-fluorocyclobutane sulfone, 2,2-difluorocyclobutane sulfone, 2,3-difluorocyclobutane sulfone, 2,4-difluorocyclobutane sulfone, 2,5-difluorocyclobutane sulfone, 3,4-difluorocyclobutane sulfone, 2-fluoro-3-methylcyclobutane sulfone, 2-fluoro-2-methylcyclobutane sulfone, 3-fluoro-3-methylcyclobutane sulfone, 3-fluoro-2-methylcyclobutane sulfone, 4-fluoro-3-methylcyclobutane sulfone, 4- Fluoro-2-methylcyclobutane sulfone, 5-fluoro-3-methylcyclobutane sulfone, 5-fluoro-2-methylcyclobutane sulfone, 2-fluoromethylcyclobutane sulfone, 3-fluoromethylcyclobutane sulfone, 2-difluoromethylcyclobutane sulfone, 3-difluoromethylcyclobutane sulfone, 2-trifluoromethylcyclobutane sulfone, 3-trifluoromethylcyclobutane sulfone, 2-fluoro-3-(trifluoromethyl)cyclobutane sulfone, 3-fluoro-3-(trifluoromethyl)cyclobutane sulfone, 4-fluoro-3-(trifluoromethyl)cyclobutane sulfone, 3-cyclobutene sulfone, 5-fluoro-3-(trifluoromethyl)cyclobutane sulfone, etc.

[0878] In addition, examples of chain sulfones include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n-butyl methyl sulfone, n-butyl ethyl sulfone, tert-butyl methyl sulfone, tert-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, and ethyl... Trifluoromethyl sulfone, perfluoroethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di(trifluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl n-propyl sulfone, difluoromethyl n-propyl sulfone, trifluoromethyl n-propyl sulfone, fluoromethyl isopropyl sulfone, difluoromethyl isopropyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl n-propyl sulfone, trifluoroethyl isopropyl sulfone, pentafluoroethyl n-propyl sulfone, pentafluoroethyl isopropyl sulfone, trifluoroethyl n-butyl sulfone, trifluoroethyl tert-butyl sulfone, pentafluoroethyl n-butyl sulfone, pentafluoroethyl tert-butyl sulfone, etc.

[0879] Among these, from the perspective of high ionic conductivity and high input-output ratio, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, tert-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, trifluoromethyl n-propyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl n-butyl sulfone, trifluoroethyl tert-butyl sulfone, trifluoromethyl n-butyl sulfone, trifluoromethyl tert-butyl sulfone, etc. are preferred.

[0880] The content of sulfone compounds is not particularly limited, and can be arbitrary as long as it does not significantly impair the effects of the present invention. In the above-mentioned solvent 100 vol%, it is usually 0.3 vol% or more, preferably 0.5 vol% or more, more preferably 1 vol% or more, and usually 40 vol% or less, preferably 35 vol% or less, more preferably 30 vol% or less. If the content of sulfone compounds is within the above range, it is easy to obtain the effect of improved durability such as cycle characteristics and storage characteristics. In addition, keeping the viscosity of the non-aqueous electrolyte within an appropriate range can avoid the decrease in conductivity, and can keep the input-output characteristics and charge-discharge rate characteristics of the non-aqueous electrolyte secondary battery within an appropriate range.

[0881] From the viewpoint of improving output characteristics, the electrolyte of the present invention preferably contains at least one compound (7) selected from lithium fluorophosphates (excluding LiPF6) and lithium salts having S=O groups as an additive.

[0882] It should be noted that when using compound (7) as an additive, it is preferable to use a compound other than compound (7) as the electrolyte salt mentioned above.

[0883] Examples of lithium fluorophosphate salts include lithium monofluorophosphate (LiPO3F) and lithium difluorophosphate (LiPO2F2).

[0884] Examples of lithium salts containing the S=O group include lithium monofluorosulfonate (FSO3Li), lithium methyl sulfate (CH3OSO3Li), lithium ethyl sulfate (C2H5OSO3Li), and 2,2,2-trifluoroethyl lithium sulfate.

[0885] As compound (7), preferably LiPO2F2, FSO3Li, or C2H5OSO3Li.

[0886] The content of compound (7) relative to the electrolyte is preferably 0.001 to 20% by mass, more preferably 0.01 to 15% by mass, even more preferably 0.1 to 10% by mass, and particularly preferably 0.1 to 7% by mass.

[0887] The electrolyte of the present invention can be further formulated with other additives as needed. Examples of other additives include metal oxides and glass.

[0888] The preferred hydrogen fluoride (HF) content in the electrolyte of the present invention is 5 to 200 ppm. The presence of HF promotes the film formation of the aforementioned additives. If the HF content is too low, the film formation ability on the negative electrode tends to decrease, and the characteristics of the electrochemical device tend to deteriorate. Conversely, if the HF content is too high, the oxidation resistance of the electrolyte tends to decrease due to the influence of HF. Even when the electrolyte of the present invention contains HF within the above-mentioned range, it does not reduce the high-temperature storage capability and capacity recovery rate of the electrochemical device.

[0889] The HF content is more preferably 10 ppm or more, and even more preferably 20 ppm or more. Furthermore, the HF content is more preferably 100 ppm or less, even more preferably 80 ppm or less, and particularly preferably 50 ppm or less.

[0890] The content of HF can be determined by neutralization titration.

[0891] The electrolyte of the present invention can be prepared using the above-mentioned components by any method.

[0892] The electrolyte of the present invention is preferably applicable to electrochemical devices such as lithium-ion secondary batteries, lithium-ion capacitors, hybrid capacitors, and double-layer capacitors. Hereinafter, a non-aqueous electrolyte battery using the electrolyte of the present invention will be described.

[0893] The aforementioned non-aqueous electrolyte battery can employ a known structure, typically comprising a positive electrode and a negative electrode capable of absorbing and releasing ions (e.g., lithium ions), as well as the electrolyte of the present invention. Such an electrochemical device incorporating the electrolyte of the present invention is also part of the present invention.

[0894] Examples of electrochemical devices include lithium-ion secondary batteries, lithium-ion capacitors, capacitors (hybrid capacitors, double-layer capacitors), free radical batteries, solar cells (especially pigment-sensitized solar cells), lithium-ion primary batteries, fuel cells, various electrochemical sensors, electrochromic elements, electrochemical switching elements, aluminum electrolytic capacitors, tantalum electrolytic capacitors, etc., with lithium-ion secondary batteries, lithium-ion capacitors, and double-layer capacitors being preferred.

[0895] Components incorporating the aforementioned electrochemical devices are also part of this invention.

[0896] The present invention also relates to a lithium-ion secondary battery having the electrolyte of the present invention.

[0897] The aforementioned lithium-ion secondary battery preferably comprises a positive electrode, a negative electrode, and the aforementioned electrolyte.

[0898] Positive electrode

[0899] The positive electrode consists of a layer of positive electrode active material containing positive electrode active material and a current collector.

[0900] There are no particular limitations on the positive electrode active material as long as it can electrochemically absorb and release lithium ions. Examples include lithium-containing transition metal composite oxides, lithium-containing transition metal phosphate compounds, sulfides, and conductive polymers. Among these, lithium-containing transition metal composite oxides and lithium-containing transition metal phosphate compounds are preferred as positive electrode active materials, and lithium-containing transition metal composite oxides that produce high voltage are particularly preferred.

[0901] The transition metals used in lithium-containing transition metal composite oxides are preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. Specific examples include lithium-cobalt composite oxides such as LiCoO2, lithium-nickel composite oxides such as LiNiO2, and lithium-manganese composite oxides such as LiMnO2, LiMn2O4, and Li2MnO4. Substances formed by replacing part of the transition metal atoms that form the main body of these lithium transition metal composite oxides with other elements such as Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W are also examples. Specific examples of the substances formed after substitution include LiNi... 0.5 Mn 0.5 O2, LiNi 0.85 Co 0.10Al 0.05 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.33 Co 0.33 Mn 0.33 O2, LiNi 0.45 Co 0.10 Al 0.45 O2, LiMn 1.8 Al 0.2 O4, LiMn 1.5 Ni 0.5 O4, etc.

[0902] Among these, LiMn is preferred as the lithium-containing transition metal composite oxide, as it exhibits high energy density even under high voltage conditions. 1.5 Ni 0.5 O4, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2.

[0903] The transition metals used in lithium-containing transition metal phosphate compounds are preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. For specific examples, iron phosphates such as LiFePO4, Li3Fe2(PO4)3, and LiFeP2O7, and cobalt phosphates such as LiCoPO4 can be cited. Substances formed by replacing part of the transition metal atoms that are the main body of these lithium transition metal phosphate compounds with other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, etc.

[0904] Examples of lithium-containing transition metal composite oxides include, for example,

[0905] Formula: Li a Mn 2-b M 1 b O4 (where 0.9≤a; 0≤b≤1.5; M) 1 Lithium-manganese spinel composite oxide (represented by at least one metal selected from Fe, Co, Ni, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge)

[0906] Formula: LiNi 1-cM 2 c O2 (where 0 ≤ c ≤ 0.5; M) 2 A lithium-nickel composite oxide represented by at least one metal selected from Fe, Co, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge, or

[0907] Formula: LiCo 1-d M 3 d O2 (where 0 ≤ d ≤ 0.5; M) 3 Lithium-cobalt composite oxides are defined as those containing at least one metal selected from Fe, Ni, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge.

[0908] From the perspective of providing lithium-ion secondary batteries with high energy density and high output, LiCoO2, LiMnO2, LiNiO2, LiMn2O4, and LiNi are preferred. 0.8 Co 0.15 Al 0.05 O2 or LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2.

[0909] Other examples of positive electrode active materials mentioned above include LiFePO4 and LiNi. 0.8 Co 0.2 O2, Li 1.2 Fe 0.4 Mn 0.4 O2, LiNi 0.5 Mn 0.5 O2, LiV3O6, etc.

[0910] Examples of sulfides include compounds with two-dimensional layered structures such as TiS2 and MoS2, and compounds with the general formula Me. x Chevrel compounds with a robust three-dimensional framework, represented by Mo6S8 (where Me represents various transition metals such as Pb, Ag, and Cu). Additionally, elemental sulfur or compounds derived from LiS can also be cited. x The term refers to organolithium sulfides, etc.

[0911] Examples of conductive polymers include p-doped and n-doped conductive polymers. Examples of conductive polymers also include polyacetylene-based polymers, polyphenylene-based polymers, heterocyclic polymers, ionic polymers, ladder-like polymers, and network polymers.

[0912] Furthermore, if the positive electrode active material contains lithium phosphate, the continuous charging characteristics are improved, which is therefore preferred. There are no restrictions on the use of lithium phosphate, but it is preferable to use a mixture of the aforementioned positive electrode active material and lithium phosphate. The lower limit of the amount of lithium phosphate used relative to the total amount of the aforementioned positive electrode active material and lithium phosphate is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, and the upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less.

[0913] Alternatively, materials with a different composition can be used, where the surface of the aforementioned positive electrode active material is coated with a substance. Examples of surface coating substances include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide; sulfates such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, and aluminum sulfate; carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate; and carbon.

[0914] These surface-adhesive substances can be attached to the surface of the positive electrode active material by methods such as dissolving or suspending them in a solvent and then impregnating and adding them to the positive electrode active material, followed by drying; dissolving or suspending the surface-adhesive substance precursor in a solvent, then impregnating and adding it to the positive electrode active material, followed by reacting it by heating or the like; or adding it to the positive electrode active material precursor and simultaneously sintering it. It should be noted that, in the case of carbon attachment, methods such as mechanically attaching carbonaceous material subsequently in the form of activated carbon can also be used.

[0915] The amount of surface-attached material, relative to the aforementioned positive electrode active material, is preferably 0.1 ppm or more by mass as a lower limit, more preferably 1 ppm or more, and even more preferably 10 ppm or more, and preferably 20% or less as an upper limit, more preferably 10% or less, and even more preferably 5% or less. The surface-attached material can suppress the oxidation reaction of the electrolyte on the surface of the positive electrode active material, thereby improving battery life. However, if the amount of material is too small, its effect will not be fully realized; if it is too large, it may sometimes hinder the movement of lithium ions, thus increasing resistance.

[0916] The shapes of positive electrode active material particles can include those previously used, such as blocky, polyhedral, spherical, ellipsoidal, plate-like, needle-like, and columnar shapes. In addition, primary particles can also condense to form secondary particles.

[0917] The tap density of the positive electrode active material is preferably 0.5 g / cm³. 3 The above, more preferably 0.8 g / cm 3 The above is further preferred to be 1.0 g / cm³. 3The above applies. If the tap density of the positive electrode active material is lower than the aforementioned lower limit, the amount of dispersion medium required during the formation of the positive electrode active material layer increases, as does the amount of conductive material and binder required. Sometimes, the filling rate of the positive electrode active material in the positive electrode active material layer is limited, thus restricting the battery capacity. By using composite oxide powder with high tap density, a high-density positive electrode active material layer can be formed. Generally, a higher tap density is better, with no particular upper limit. However, if it is too high, the diffusion of lithium ions using the electrolyte as a medium within the positive electrode active material layer may become the rate-determining step, easily reducing the loading characteristics. Therefore, the upper limit is preferably 4.0 g / cm³. 3 The preferred value is 3.7 g / cm³. 3 The following is a further preferred value: 3.5 g / cm³ 3 the following.

[0918] It should be noted that in this invention, for the tap density, 5-10g of the positive electrode active material powder is placed into a 10ml glass graduated cylinder, and the powder filling density (tap density) is measured in g / cm³ when the powder is tapped 200 times at an amplitude of approximately 20mm. 3 Let's find out.

[0919] The median particle size d50 (secondary particle size in the case of primary particle aggregation to form secondary particles) of the positive electrode active material is preferably 0.3 μm or more, more preferably 0.5 μm or more, further preferably 0.8 μm or more, and most preferably 1.0 μm or more. It is also preferably 30 μm or less, more preferably 27 μm or less, further preferably 25 μm or less, and most preferably 22 μm or less. If it is below the lower limit, a high tap density may not be obtained. If it exceeds the upper limit, the diffusion of lithium within the particles takes longer, which may sometimes lead to a decrease in battery performance. Furthermore, during the fabrication of the positive electrode, i.e., when the active material, conductive material, binder, etc., are slurried with a solvent and coated into a thin film, problems such as stretching may occur. Here, by mixing two or more of the above-mentioned positive electrode active materials with different median particle sizes d50, the filling properties during positive electrode fabrication can be further improved.

[0920] It should be noted that in this invention, the median particle size d50 is determined using a known laser diffraction / scattering particle size distribution measuring device. When using a HORIBA LA-920 particle size meter, a 0.1% by mass sodium hexametaphosphate aqueous solution is used as the dispersion medium. After ultrasonic dispersion for 5 minutes, the refractive index is set to 1.24 for measurement.

[0921] When secondary particles are formed by the aggregation of primary particles, the average primary particle size of the aforementioned positive electrode active material is preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.2 μm or more, with an upper limit preferably 5 μm or less, more preferably 4 μm or less, even more preferably 3 μm or less, and most preferably 2 μm or less. If the upper limit is exceeded, it becomes difficult to form spherical secondary particles, which adversely affects the powder filling properties or significantly reduces the specific surface area, thus increasing the possibility of reduced battery performance such as output characteristics. Conversely, if the lower limit is exceeded, problems such as poor reversibility of charge and discharge may occur due to underdeveloped crystallization.

[0922] It should be noted that in this invention, the average primary particle size can be determined by observation using a scanning electron microscope (SEM). Specifically, in a 10,000x magnification photograph, the longest values ​​of the intercepts of the left and right boundary lines of any 50 primary particles to the horizontal straight line are calculated, and the average value is taken.

[0923] The preferred BET specific surface area of ​​the positive electrode active material is 0.1 m². 2 / g or more, preferably 0.2m 2 / g or more, further preferably 0.3m 2 / g or more, with an upper limit preferably of 50m 2 / g or less, preferably 40m 2 / g or less, more preferably 30m 2 Below / g. If the BET specific surface area is less than this range, the battery performance is prone to deterioration; if it is greater than this range, the tap density is difficult to improve, and sometimes the coating properties during the formation of the positive electrode active material layer are prone to problems.

[0924] It should be noted that in this invention, the BET specific surface area is defined by measuring the value using a surface area meter (e.g., a fully automatic surface area measuring device manufactured by Riken Okura Co., Ltd.) after the sample has been pre-dried at 150°C for 30 minutes under nitrogen flow. The value is then determined by measuring the nitrogen adsorption BET 1-point method based on the gas flow method using a nitrogen-helium mixed gas that has been accurately adjusted so that the relative pressure of nitrogen relative to atmospheric pressure is 0.3.

[0925] When the lithium-ion secondary battery of the present invention is used as a large lithium-ion secondary battery for hybrid electric vehicles or distributed power sources, high output is required. Therefore, the particles of the positive electrode active material are preferably mainly secondary particles.

[0926] The positive electrode active material is preferably composed of secondary particles with an average particle size of 40 μm or less and containing 0.5 to 7.0 vol% of primary particles with a particle size of 1 μm or less. By containing primary particles with a particle size of 1 μm or less, the contact area with the electrolyte is increased, which can further accelerate the diffusion of lithium ions between the electrode and the electrolyte, thereby improving the output performance of the battery.

[0927] As a method for manufacturing positive electrode active materials, conventional methods for manufacturing inorganic compounds can be used. In particular, various methods can be conceived for producing spherical or ellipsoidal active materials. For example, one method is to dissolve or disperse a transition metal raw material in a solvent such as water, adjust the pH while stirring to produce a spherical precursor, dry it as needed, add a Li source such as LiOH, Li2CO3, or LiNO3, and calcine it at a high temperature to obtain the active material.

[0928] To manufacture the positive electrode, the aforementioned positive electrode active materials can be used alone, or in any combination or ratio, using two or more materials with different compositions. As a preferred combination in this case, LiCoO2 and LiNi can be cited as examples. 0.33 Co 0.33 Mn 0.33 A combination of substances formed by replacing part of Mn in LiMn2O4 with O2 or other transition metals, or a combination of substances formed by replacing part of Co in LiCoO2 or other transition metals.

[0929] From the perspective of high battery capacity, the content of the aforementioned positive electrode active material is preferably 50 to 99.5% by mass of the positive electrode compound, more preferably 80 to 99% by mass. Furthermore, the content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. The upper limit is preferably 99% by mass or less, more preferably 98% by mass or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the battery capacity may sometimes be insufficient. Conversely, if the content is too high, the strength of the positive electrode may sometimes be insufficient.

[0930] The above-mentioned positive electrode mixture is further preferably composed of binder, thickener and conductive material.

[0931] As the aforementioned binder, any material safe for the solvents and electrolytes used in electrode manufacturing can be used. Examples include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, chitosan, alginate, polyacrylic acid, polyimide, cellulose, and nitrocellulose; rubber-like polymers such as SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR (acrylonitrile-butadiene rubber), and ethylene-propylene rubber; and styrene-butadiene-styrene block copolymers. or their hydrides; thermoplastic elastomers such as EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-styrene copolymer, styrene-isoprene-styrene block copolymer, or their hydrides; soft resinous polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymer, and propylene-α-olefin copolymer; fluorinated polymers such as polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride copolymer, and tetrafluoroethylene-ethylene copolymer; and polymer compositions with ion conductivity of alkali metal ions (especially lithium ions). They can be used individually or in any combination and ratio of two or more.

[0932] The binder content, calculated as the proportion of binder in the positive electrode active material layer, is typically 0.1% by mass or more, preferably 1% by mass or more, more preferably 1.5% by mass or more, and typically 80% by mass or less, preferably 60% by mass or less, more preferably 40% by mass or less, and most preferably 10% by mass or less. If the binder proportion is too low, the mechanical strength of the positive electrode may be insufficient, failing to adequately retain the positive electrode active material, leading to deterioration of battery performance such as cycle characteristics. On the other hand, if the proportion is too high, it may sometimes result in a decrease in battery capacity and conductivity.

[0933] Examples of thickeners include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, polyvinylpyrrolidone, and their salts. A single agent can be used, or two or more can be used in any combination and proportion.

[0934] The ratio of thickener to active material is typically 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and typically 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. If it is below this range, the coatability may be significantly reduced. If it is above this range, the proportion of active material in the positive electrode active material layer decreases, sometimes resulting in problems such as reduced battery capacity and increased resistance between positive electrode active materials.

[0935] As the aforementioned conductive material, any known conductive material can be used. Specific examples include metallic materials such as copper and nickel; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal cracking black; and carbon materials such as needle coke, carbon nanotubes, fullerenes, and VGCF. It should be noted that one of these materials can be used alone, or two or more can be used in any combination and ratio. The conductive material is used in the positive electrode active material layer at a content of typically 0.01% by mass or more, preferably 0.1% by mass or more, and more preferably 1% by mass or more; and at a content of typically 50% by mass or less, preferably 30% by mass or less, and more preferably 15% by mass or less. If the content is below this range, the conductivity may sometimes become insufficient. Conversely, if the content is above this range, the battery capacity may sometimes decrease.

[0936] As a solvent used to form the slurry, there are no particular restrictions on its type, as long as it can dissolve or disperse the positive electrode active material, conductive material, binder, and thickener used as needed. Either aqueous or organic solvents can be used. Examples of aqueous solvents include water, mixtures of alcohol and water, etc. Examples of organic solvents include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N,N-dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide, and tetrahydrofuran (THF); amides such as N-methylpyrrolidone (NMP), dimethylformamide, and dimethylacetamide; and aprotic polar solvents such as hexamethylphosphoramide and dimethyl sulfoxide, etc.

[0937] Materials that can be used as current collectors for the positive electrode include metallic materials such as aluminum, titanium, tantalum, stainless steel, nickel, or their alloys; and carbon materials such as carbon cloth and carbon paper. Among these, metallic materials are preferred, especially aluminum or its alloys.

[0938] In the case of metallic materials, examples of current collector shapes include metal foil, metal cylinder, metal coil, metal plate, metal film, expanded metal, perforated metal, and foamed metal; in the case of carbon materials, examples include carbon plate, carbon film, and carbon cylinder. Metal film is preferred. It should be noted that the film can also be appropriately formed into a mesh. The thickness of the film is arbitrary, typically 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and typically 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less. If the film is thinner than this range, the strength required for current collection may be insufficient. Conversely, if the film is thicker than this range, operability may be compromised.

[0939] Furthermore, from the perspective of reducing the electrical contact resistance between the current collector and the positive electrode active material layer, it is preferable to coat the surface of the current collector with a conductive additive. Examples of conductive additives include: carbon; and precious metals such as gold, platinum, and silver.

[0940] The ratio of the current collector thickness to the thickness of the positive electrode active material layer is not particularly limited, but the value of (thickness of the positive electrode active material layer on one side before electrolyte injection) / (thickness of the current collector) is preferably 20 or less, more preferably 15 or less, most preferably 10 or less, and preferably 0.5 or more, more preferably 0.8 or more, and most preferably 1 or more. If it exceeds this range, the current collector may generate heat due to Joule heating during high current density charging and discharging. If it is below this range, the volume ratio of the current collector to the positive electrode active material increases, and sometimes the battery capacity decreases.

[0941] The positive electrode can be manufactured using conventional methods. For example, a method can be used to prepare a slurry-like positive electrode mixture by adding the aforementioned binder, thickener, conductive material, solvent, etc., to the positive electrode active material, coating it onto a current collector, drying it, and then pressing it to achieve high density.

[0942] The aforementioned high density can be achieved through hand pressing, roller pressing, etc. The preferred density of the positive electrode active material layer is 1.5 g / cm³. 3 The above, more preferably 2g / cm 3 The above is further optimized to be 2.2 g / cm³. 3 In addition, the preferred value is 5g / cm³. 3 The following is more preferably 4.5 g / cm³. 3 The following is a further preferred value: 4g / cm 3 The following range applies. If this range is exceeded, the electrolyte's permeability to the vicinity of the current collector / active material interface decreases, particularly reducing charge-discharge characteristics at high current densities, sometimes resulting in insufficient output. Conversely, if the range is below this range, the conductivity between active materials decreases, battery resistance increases, and sometimes high output is also unattainable.

[0943] When using the electrolyte of the present invention, from the viewpoint of high output and improved stability at high temperatures, it is preferable that the area of ​​the positive electrode active material layer is larger than the outer surface area of ​​the battery casing. Specifically, the total area of ​​the positive electrodes is preferably 15 times or more, and more preferably 40 times or more, relative to the surface area of ​​the secondary battery casing. The outer surface area of ​​the battery casing refers to the total area calculated based on the length, width, and thickness of the casing portion filled with the power generation element, excluding the terminal protrusions, in the case of a square-shaped casing with a base. In the case of a cylindrical-shaped casing with a base, it is the geometric surface area when the casing portion filled with the power generation element, excluding the terminal protrusions, is approximately cylindrical. The total area of ​​the positive electrodes refers to the geometric surface area of ​​the positive electrode compound layer opposite to the compound layer containing the negative electrode active material; in a structure where the positive electrode compound layer is formed on both sides with a current collector foil in between, it refers to the sum of the areas of each side calculated separately.

[0944] The thickness of the positive electrode plate is not particularly limited. From the viewpoint of high capacity and high output, the thickness of the additive layer obtained by subtracting the thickness of the metal foil of the core material is preferably 10 μm or more, more preferably 20 μm or more, and preferably 500 μm or less, more preferably 450 μm or less, as a lower limit for one side of the current collector.

[0945] Alternatively, materials with a different composition can be used, where the surface of the positive electrode plate is coated with a substance. Examples of such surface coating substances include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide; sulfates such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, and aluminum sulfate; carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate; and carbon.

[0946] <Negative electrode>

[0947] The negative electrode consists of a layer of negative electrode active material containing negative electrode active material and a current collector.

[0948] As a negative electrode material, there are no particular restrictions as long as it can electrochemically absorb and release lithium ions. Specific examples include carbon materials, alloy materials, lithium-containing metal composite oxide materials, and conductive polymers. One type can be used alone, or two or more can be used in any combination.

[0949] Examples of negative electrode active materials include thermal decomposition products of organic matter under various thermal decomposition conditions, carbonaceous materials such as artificial graphite and natural graphite that can absorb and release lithium; metal oxide materials such as tin oxide and silicon oxide that can absorb and release lithium; lithium metal; various lithium alloys; and lithium-containing metal composite oxide materials. Two or more of these negative electrode active materials can be used in combination.

[0950] As a carbonaceous material capable of absorbing and releasing lithium, artificial graphite or refined natural graphite, manufactured by high-temperature treatment of easily graphitizable pitch obtained from various raw materials, or a substance obtained by carbonizing these graphites after surface treatment with organic materials such as pitch, is preferred. From the viewpoint of achieving a good balance between initial irreversible capacity and high current density charge-discharge characteristics, the following materials are more preferred: natural graphite; artificial graphite; carbonaceous materials obtained by heat-treating artificial carbonaceous materials and artificial graphitic materials once or more in the range of 400 to 3200°C; carbonaceous materials in which the negative electrode active material layer contains at least two or more types of carbonaceous materials with different crystallinity and / or has a contact interface of said different types of carbonaceous materials; carbonaceous materials in which the negative electrode active material layer has a contact interface of at least two or more types of carbonaceous materials with different orientations. In addition, these carbon materials can be used alone or in any combination and ratio of two or more.

[0951] Examples of carbonaceous materials obtained by heat-treating artificial carbonaceous materials and artificial graphitic materials at a temperature of 400–3200°C or higher include coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, and carbonaceous materials obtained by oxidizing these pitches, needle coke, pitch coke, carbonizing agents obtained by partially graphitizing these pitches, furnace black, acetylene black, pitch-based carbon fibers, and other organic thermal decomposition products, carbonizable organic materials and their carbides, or solutions obtained by dissolving carbonizable organic materials in low-molecular-weight organic solvents such as benzene, toluene, xylene, quinoline, and n-hexane, and their carbides.

[0952] The metallic material used as the aforementioned negative electrode active material (excluding lithium-titanium composite oxides) can be any of elemental lithium, elemental metals and alloys forming lithium alloys, or their oxides, carbides, nitrides, silicides, sulfides, or phosphides, as long as it can absorb and release lithium, without particular limitation. As for the elemental metals and alloys forming lithium alloys, materials containing group 13 and 14 metallic or semi-metallic elements are preferred, more preferably elemental metals of aluminum, silicon, and tin (hereinafter referred to as "specific metallic elements") and alloys or compounds containing these atoms. They can be used individually or in any combination and ratio of two or more.

[0953] As the negative electrode active material having at least one atom selected from specific metal elements, any one of the metal simple substances of specific metal elements, alloys containing two or more specific metal elements, alloys containing one or two or more specific metal elements and one or two or more other metal elements, and compounds containing one or two or more specific metal elements and composite compounds such as oxides, carbides, nitrides, silicides, sulfides or phosphides of the compounds can be cited. By using these metal simple substances, alloys or metal compounds as the negative electrode active material, high capacity of the battery can be achieved.

[0954] In addition, compounds in which these composite compounds are complexly bonded with various elements such as metal simple substances, alloys or non-metal elements can also be cited. Specifically, for example, in the case of silicon and tin, alloys of these elements and metals that do not function as negative electrodes can be used. For example, in the case of tin, combinations of tin and metals that function as negative electrodes other than silicon, and further metals and non-metal elements that do not function as negative electrodes can also be used, such complex compounds containing 5 to 6 elements.

[0955] Specifically, Si simple substance, SiB4, SiB6, Mg2Si, Ni2Si, TiSi2, MoSi2, CoSi2, NiSi2, CaSi2, CrSi2, Cu6Si, FeSi2, MnSi2, NbSi2, TaSi2, VSi2, WSi2, ZnSi2, SiC, Si3N4, Si2N2O, SiO v (0 < v ≤ 2), LiSiO, or tin simple substance, SnSiO3, LiSnO, Mg2Sn, SnO w (0 < w ≤ 2).

[0956] In addition, composite materials having Si or Sn as the first constituent element and further containing the second and third constituent elements can be cited. The second constituent element is, for example, at least one of cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium and zirconium. The third constituent element is, for example, at least one of boron, carbon, aluminum and phosphorus.

[0957] Particularly, from the viewpoint of obtaining high battery capacity and excellent battery characteristics, as the above-mentioned metal materials, silicon or tin simple substances (trace impurities may be contained), SiO v (0 < v ≤ 2), SnO w (0 ≤ w ≤ 2), Si-Co-C composite material, Si-Ni-C composite material, Sn-Co-C composite material, Sn-Ni-C composite material are preferred.

[0958] As for lithium-containing metal composite oxide materials used as negative electrode active materials, there are no particular limitations as long as they can absorb and release lithium. From the perspective of high current density charge and discharge characteristics, materials containing titanium and lithium are preferred, lithium-containing composite metal oxide materials containing titanium are more preferred, and composite oxides of lithium and titanium (hereinafter referred to as "lithium-titanium composite oxides") are even more preferred. That is, if lithium-titanium composite oxides with a spinel structure are contained in or used in the negative electrode active material for electrolyte batteries, the output resistance is greatly reduced, and therefore it is particularly preferred.

[0959] The preferred lithium-titanium composite oxide is of the following general formula:

[0960] Li x Ti y M z O4

[0961] [In the formula, M represents at least one element selected from Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb.]

[0962] The compound represented.

[0963] In the above composition, due to

[0964] (i)1.2≤x≤1.4, 1.5≤y≤1.7, z=0

[0965] (ii)0.9≤x≤1.1, 1.9≤y≤2.1, z=0

[0966] (iii)0.7≤x≤0.9, 2.1≤y≤2.3, z=0

[0967] The structure offers a good balance of battery performance, making it a particularly preferred choice.

[0968] A particularly preferred representative composition of the above-mentioned compound is Li in (i). 4 / 3 Ti 5 / 3 O4, in (ii) is Li1Ti2O4, and in (iii) is Li 4 / 5 Ti 11 / 5 O4. Additionally, for structures where Z≠0, Li can be cited as an example. 4 / 3 Ti 4 / 3 Al 1 / 3 O4 is the preferred structure.

[0969] The aforementioned negative electrode mixture is further preferably composed of binders, thickeners, and conductive materials.

[0970] As the binder described above, the same binder used for the positive electrode as described above can be cited. The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 8% by mass or less. If the ratio of the binder to the negative electrode active material exceeds the above range, the increased binder ratio will lead to a decrease in battery capacity since the binder dosage does not contribute to battery capacity. Conversely, if the ratio is below the above range, the strength of the negative electrode may decrease.

[0971] In particular, when the main component contains a rubbery polymer represented by SBR, the proportion of the binder relative to the negative electrode active material is typically 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and typically 5% by mass or less, preferably 3% by mass or less, and even more preferably 2% by mass or less. Furthermore, when the main component contains a fluorinated polymer represented by polyvinylidene fluoride, the proportion relative to the negative electrode active material is typically 1% by mass or more, preferably 2% by mass or more, and even more preferably 3% by mass or more, and typically 15% by mass or less, preferably 10% by mass or less, and even more preferably 8% by mass or less.

[0972] As the aforementioned thickener, the same thickeners used for the positive electrode as described above can be cited. The ratio of the thickener to the negative electrode active material is typically 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and typically 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. If the ratio of the thickener to the negative electrode active material is lower than the above range, the coatability will be significantly reduced. Furthermore, if the ratio exceeds the above range, the proportion of the negative electrode active material in the negative electrode active material layer will decrease, resulting in a decrease in battery capacity and an increase in the resistance between the negative electrode active materials.

[0973] Examples of conductive materials that can serve as negative electrodes include metallic materials such as copper and nickel, and carbon materials such as graphite and carbon black.

[0974] As a solvent used to form the slurry, there are no particular restrictions on its type, as long as it can dissolve or disperse the negative electrode active material, binder, and thickener and conductive material as needed. Any of the aqueous and organic solvents can be used.

[0975] Examples of aqueous solvents include water and alcohols. Examples of organic solvents include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethylenetriamine, N,N-dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphoramide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, and hexane.

[0976] Materials that can be used as current collectors for the negative electrode include copper, nickel, or stainless steel. Among these, copper foil is preferred due to its ease of processing into thin films and its cost.

[0977] The thickness of the current collector is typically 1 μm or more, preferably 5 μm or more, typically 100 μm or less, and preferably 50 μm or less. If the thickness of the negative electrode current collector is too thick, the overall capacity of the battery may be excessively reduced; conversely, if it is too thin, it may become difficult to process.

[0978] The negative electrode can be manufactured using conventional methods. For example, a method can be used to prepare a slurry by adding the aforementioned binder, thickener, conductive material, solvent, etc., to the negative electrode material, coating it onto a current collector, drying it, and then pressing it to achieve high density. Alternatively, when using alloy materials, a method can be used to form a thin film layer (negative electrode active material layer) containing the aforementioned negative electrode active material by methods such as vapor deposition, sputtering, or plating.

[0979] There are no particular restrictions on the electrode structure when the negative electrode active material is polarized, but the density of the negative electrode active material present on the current collector is preferably 1 g·cm³. -3 The above is further preferred to be 1.2 g·cm³. -3 The above, especially preferred, is 1.3 g·cm³. -3 In addition, the preferred value is 2.2 g·cm³. -3 The following is a preferred value: 2.1 g·cm³ -3 The following is a further preferred value: 2.0 g·cm³ -3 The following is particularly preferred: 1.9 g·cm³ -3 The following applies. If the density of the negative electrode active material on the current collector exceeds the above range, it may damage the negative electrode active material particles, leading to an increase in initial irreversible capacity and deterioration of high current density charge-discharge characteristics due to reduced electrolyte permeability near the current collector / negative electrode active material interface. Conversely, if the density is below the above range, there will be a decrease in conductivity between the negative electrode active materials, an increase in battery resistance, and a decrease in capacity per unit volume.

[0980] The thickness of the negative electrode plate is designed according to the positive electrode plate used and is not particularly limited. The thickness of the compound layer after subtracting the thickness of the core material metal foil is generally expected to be 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and usually 300 μm or less, preferably 280 μm or less, more preferably 250 μm or less.

[0981] Alternatively, materials with a different composition can be used, where the surface of the aforementioned negative electrode plate is coated with a substance. Examples of such surface coating substances include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide; sulfates such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, and aluminum sulfate; and carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate.

[0982] <Isolation Component>

[0983] The lithium-ion secondary battery of the present invention preferably further includes an separator.

[0984] The material and shape of the aforementioned separator are not particularly limited as long as they are stable in the electrolyte and have excellent liquid retention properties; known materials and shapes can be used. Among these, it is preferable to use articles in the form of porous sheets or non-woven fabrics with excellent liquid retention properties, formed from materials that are stable relative to the electrolyte of the present invention, such as resins, glass fibers, inorganic materials, etc.

[0985] Materials used for resin and fiberglass separators include, for example, polyolefins such as polyethylene and polypropylene, aromatic polyamides, polytetrafluoroethylene, polyethersulfone, and glass filters. Polypropylene / polyethylene two-layer membranes, polypropylene / polyethylene / polypropylene three-layer membranes, etc., can be used individually or in any combination and ratio of two or more materials. From the perspective of good electrolyte permeability and shutdown effect, the separators are preferably porous sheets or non-woven fabrics made from polyolefins such as polyethylene and polypropylene.

[0986] The thickness of the separator is arbitrary, typically 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and typically 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, insulation and mechanical strength will decrease. Conversely, if the separator is too thick than the above range, not only will battery performance, such as rate characteristics, decrease, but the overall energy density of the electrolyte battery will also decrease.

[0987] Furthermore, when using porous materials such as porous sheets or nonwoven fabrics as separators, the porosity of the separator is arbitrary, typically 20% or more, preferably 35% or more, more preferably 45% or more, and typically 90% or less, preferably 85% or less, more preferably 75% or less. If the porosity is too small compared to the above ranges, there is a tendency for the film resistivity to increase and the rate capability to deteriorate. Conversely, if the porosity is too large compared to the above ranges, there is a tendency for the mechanical strength and insulation properties of the separator to decrease.

[0988] Furthermore, the average aperture of the separator is arbitrary, typically 0.5 μm or less, preferably 0.2 μm or less, and usually 0.05 μm or more. If the average aperture exceeds the above range, short circuits are likely to occur. Conversely, if it is below the above range, the film resistance increases and the rate capability decreases.

[0989] On the other hand, as inorganic materials, for example, oxides such as aluminum oxide and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate can be used, and materials in particle shape or fiber shape can be used.

[0990] As the form, materials in the shape of a thin film, such as nonwoven fabric, woven fabric, or microporous membrane, can be used. In the case of a thin film shape, materials with a pore size of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferred. In addition to the above-mentioned independent thin film shapes, the following separators can also be used: separators formed by using a resin-based adhesive to form a composite porous layer containing the aforementioned inorganic particles on the surface of the positive and / or negative electrodes. For example, a porous layer can be formed on both sides of the positive electrode using a fluororesin as an adhesive, with 90% of the alumina particles having a particle size of less than 1 μm.

[0991] Battery Design

[0992] The electrode assembly can be either a stacked electrode assembly consisting of the positive and negative electrode plates separated by the separator, or an electrode assembly consisting of the positive and negative electrode plates wound into a spiral shape separated by the separator. The proportion of the electrode assembly volume in the battery internal volume (hereinafter referred to as the electrode assembly occupancy rate) is typically 40% or more, preferably 50% or more, and typically 90% or less, preferably 80% or less.

[0993] If the electrode assembly occupancy rate is below the above range, the battery capacity will be smaller. In addition, if it exceeds the above range, there will be less space, and when the battery becomes hot, the components will expand or the vapor pressure of the liquid components of the electrolyte will increase, thereby increasing the internal pressure. This may sometimes reduce the battery's charge-discharge repeatability, high-temperature storage and other characteristics, and cause the gas release valve that releases the internal pressure to the outside to activate.

[0994] There are no particular limitations on the current collector structure. However, to more effectively achieve the improved charge-discharge characteristics with high current density provided by the electrolyte of the present invention, it is preferable to manufacture a structure that reduces the resistance of the wiring and bonding portions. With such a reduction in internal resistance, the effects of using the electrolyte of the present invention can be particularly well realized.

[0995] When the electrode assembly has the aforementioned stacked structure, it is preferable to use a structure formed by bundling and welding the metal core portions of each electrode layer into terminals. As the area of ​​a single electrode increases, the internal resistance also increases; therefore, it is also preferable to use a method that reduces resistance by providing multiple terminals within the electrode. When the electrode assembly has the aforementioned wound structure, the internal resistance can be reduced by providing multiple wire structures at the positive and negative electrodes respectively and bundling them into terminals.

[0996] There are no particular restrictions on the material of the outer casing, as long as it is a substance stable relative to the electrolyte used. Specifically, nickel-plated steel, stainless steel, aluminum or aluminum alloy, magnesium alloy, or laminated films of resin and aluminum foil can be used. From a lightweight perspective, aluminum or aluminum alloy laminates are preferred.

[0997] When using a metal casing, examples include casings where metals are fused together using laser welding, resistance welding, or ultrasonic welding to form a sealed structure, or casings where the metal is bonded together using resin gaskets to form a kashime-like structure. When using a laminated casing, examples include casings where resin layers are thermally fused together to form a sealed structure. To improve sealing, a resin different from the resin used in the laminate can be used between the resin layers. In particular, when a sealed structure is formed by thermally fusing resin layers with current collectors, since a bond is formed between the metal and the resin, it is preferable to use a resin with polar groups or a modified resin with introduced polar groups as an intermediate resin.

[0998] The lithium-ion secondary battery of the present invention can have any shape, such as cylindrical, square, laminated, coin-shaped, or large. It should be noted that the shape and configuration of the positive electrode, negative electrode, and separator can be modified according to the shape of the respective battery.

[0999] In addition, components incorporating the lithium-ion secondary battery of the present invention are also part of the present invention.

[1000] Furthermore, a preferred embodiment of the lithium-ion secondary battery is characterized by comprising a positive electrode, a negative electrode, and the aforementioned electrolyte. The positive electrode comprises a positive electrode current collector and a positive electrode active material layer containing a positive electrode active material, wherein the positive electrode active material contains Mn. Because it comprises a positive electrode active material layer containing Mn, the high-temperature storage characteristics of the aforementioned lithium-ion secondary battery are superior.

[1001] From the perspective of providing lithium-ion secondary batteries with high energy density and high output, LiMn is preferred as the aforementioned Mn-containing positive electrode active material. 1.5 Ni 0.5 O4, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2.

[1002] The content of the aforementioned positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. Furthermore, the upper limit is preferably 99% by mass or less, more preferably 98% by mass or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the battery capacity may sometimes become insufficient. Conversely, if the content is too high, the strength of the positive electrode may sometimes be insufficient.

[1003] The aforementioned positive electrode active material layer may also contain conductive materials, thickeners, and binders.

[1004] As the aforementioned binder, any material that is safe for the solvents and electrolytes used in electrode manufacturing can be used. Examples include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose, NBR (acrylonitrile-butadiene rubber), fluororubber, etc. Ethylene-propylene rubber, styrene-butadiene-styrene block copolymers or their hydrogenated forms, EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-ethylene copolymer, styrene-isoprene-styrene block copolymers or their hydrogenated forms, syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymer, propylene-α-olefin copolymer, fluorinated polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer, and polymeric compositions with ion conductivity of alkali metal ions (especially lithium ions), etc. It should be noted that these substances can be used alone or in any combination and ratio of two or more.

[1005] The binder content, calculated as the proportion of binder in the positive electrode active material layer, is typically 0.1% by mass or more, preferably 1% by mass or more, more preferably 1.5% by mass or more, and typically 80% by mass or less, preferably 60% by mass or less, more preferably 40% by mass or less, and most preferably 10% by mass or less. If the binder proportion is too low, the mechanical strength of the positive electrode may be insufficient, failing to adequately retain the positive electrode active material, leading to deterioration of battery performance such as cycle characteristics. On the other hand, if the proportion is too high, it may sometimes result in a decrease in battery capacity and conductivity.

[1006] Examples of thickeners include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and their salts. A single agent can be used, or two or more can be used in any combination and proportion.

[1007] The ratio of thickener to active material is typically 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and typically 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. If it is below this range, the coatability may be significantly reduced. If it is above this range, the proportion of active material in the positive electrode active material layer decreases, sometimes resulting in problems such as reduced battery capacity and increased resistance between positive electrode active materials.

[1008] As the aforementioned conductive material, any known conductive material can be used. Specific examples include metallic materials such as copper and nickel; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black; and amorphous carbon such as needle coke. It should be noted that one of these materials can be used alone, or two or more can be used in any combination and ratio. The conductive material is typically used in the positive electrode active material layer at a concentration of 0.01% by mass or more, preferably 0.1% by mass or more, and more preferably 1% by mass or more. It is also typically used at a concentration of 50% by mass or less, preferably 30% by mass or less, and more preferably 15% by mass or less. If the content is below this range, the conductivity may become insufficient. Conversely, if the content is above this range, the battery capacity may decrease.

[1009] From the perspective of further improving high-temperature storage characteristics, the aforementioned positive electrode current collector is preferably made of a valve metal or its alloy. Examples of valve metals include aluminum, titanium, tantalum, and chromium. More preferably, the aforementioned positive electrode current collector is made of aluminum or an aluminum alloy.

[1010] From the perspective of further improving the high-temperature storage characteristics of the aforementioned lithium-ion secondary battery, the portion in contact with the electrolyte in the part electrically connected to the positive electrode current collector is preferably made of valve metal or its alloy. In particular, the portions of the battery casing, and the wires, safety valves, etc., housed within the battery casing, that are electrically connected to the positive electrode current collector and in contact with the non-aqueous electrolyte, are preferably made of valve metal or its alloy. Stainless steel covered with valve metal or its alloy may also be used.

[1011] The manufacturing method of the above positive electrode is as described above. For example, a method can be described by adding the above-mentioned binder, thickener, conductive material, solvent, etc. to the above-mentioned positive electrode active material to make a slurry-like positive electrode mixture, coating it on the above-mentioned positive electrode current collector, drying it, and then pressing it to make it high-density.

[1012] The structure of the negative electrode is as shown above.

[1013] The aforementioned double-layer capacitor may have a positive electrode, a negative electrode, and the aforementioned electrolyte.

[1014] In the above-mentioned double-layer capacitor, at least one of the positive and negative electrodes is a polarized electrode. The following electrodes, which are detailed in Japanese Patent Application Publication No. 9-7896, can be used as polarized and non-polarized electrodes.

[1015] The polarization electrode used in this invention, primarily composed of activated carbon, preferably contains activated carbon with a large specific surface area and conductive materials such as carbon black, which imparts electronic conductivity. The polarization electrode can be formed by various methods. For example, by mixing activated carbon powder, carbon black, and phenolic resin, pressing them into shape, and then sintering and activating them in an inert gas atmosphere and a water vapor atmosphere, a polarization electrode containing activated carbon and carbon black can be formed. Preferably, this polarization electrode is bonded to the current collector using a conductive adhesive or the like.

[1016] Alternatively, activated carbon powder, carbon black, and binder can be mixed in the presence of alcohol, molded into sheets, and dried to form a polarized electrode. For example, polytetrafluoroethylene (PTFE) can be used as the binder. Alternatively, activated carbon powder, carbon black, binder, and solvent can be mixed to form a slurry, which is then coated onto the metal foil of the current collector and dried to form a polarized electrode integrated with the current collector.

[1017] A double-layer capacitor can be made by using a polarized electrode with activated carbon as the main body on both electrodes, or it can be constructed by using a non-polarized electrode on one side. For example, it can be constructed by combining a positive electrode with a battery active material such as metal oxide as the main body and a negative electrode with activated carbon as the main body. It can also be constructed by combining a negative electrode with a carbon material that can reversibly absorb and release lithium ions, or a negative electrode with lithium metal or lithium alloy as the main body, and a polarized positive electrode with activated carbon as the main body.

[1018] Alternatively, carbon black, graphite, expanded graphite, porous carbon, carbon nanotubes, carbon nanotubes, Ketjen black, and other carbonaceous materials can be used to replace activated carbon or in combination with activated carbon.

[1019] As a non-polarized electrode, a carbon material capable of reversibly absorbing and releasing lithium ions is preferred, and the substance obtained by absorbing lithium ions from this carbon material is used as the electrode. In this case, a lithium salt can be used as the electrolyte. Based on this configuration, a higher withstand voltage exceeding 4V can be obtained for the double-layer capacitor.

[1020] The solvent used in the preparation of the slurry for electrode fabrication is preferably a solvent for dissolving the binder. Depending on the type of binder, N-methylpyrrolidone, dimethylformamide, toluene, xylene, isophorone, methyl ethyl ketone, ethyl acetate, methyl acetate, dimethyl phthalate, ethanol, methanol, butanol, or water can be selected appropriately.

[1021] Activated carbon used in polarization electrodes includes phenolic resin activated carbon, coconut shell activated carbon, and petroleum coke activated carbon. Among these, petroleum coke activated carbon or phenolic resin activated carbon is preferred for achieving a larger capacity. Furthermore, activation treatment methods for activated carbon include steam activation and molten KOH activation; for even greater capacity, activated carbon treated with molten KOH is preferred.

[1022] Preferred conductive materials for use in polarization electrodes include carbon black, Ketjen black, acetylene black, natural graphite, artificial graphite, metal fibers, conductive titanium dioxide, and ruthenium oxide. Regarding the mixing amount of conductive materials such as carbon black used in the polarization electrode, to obtain good conductivity (low internal resistance), and because an excessive amount would reduce the capacity of the product, the preferred mixing amount with activated carbon is 1 to 50% by mass.

[1023] Furthermore, for the activated carbon used in the polarization electrode, in order to obtain a double-layer capacitor with high capacitance and low internal resistance, it is preferable to use an average particle size of 20 μm or less and a specific surface area of ​​1500–3000 m². 2 / g of activated carbon. Furthermore, preferred carbon materials for constructing electrodes primarily composed of carbon materials capable of reversibly absorbing and releasing lithium ions include natural graphite, artificial graphite, graphitized mesophase carbon microspheres, graphitized whiskers, vapor-grown carbon fibers, sintered furfuryl alcohol resin, or sintered Novolak resin.

[1024] The current collector only needs to be chemically and electrochemically corrosion-resistant. For current collectors with activated carbon as the main polarized electrode, stainless steel, aluminum, titanium, or tantalum are preferred. Stainless steel or aluminum are particularly preferred materials in terms of both the properties and cost of the resulting electric double-layer capacitor. For current collectors with carbon materials as the main electrode capable of reversibly absorbing and releasing lithium ions, stainless steel, copper, or nickel are preferred.

[1025] In addition, in order to pre-absorb lithium ions into carbon materials that can reversibly absorb and release lithium ions, the following methods exist: (1) a method of pre-mixing powdered lithium into carbon materials that can reversibly absorb and release lithium ions; (2) placing lithium foil on an electrode formed by carbon materials that can reversibly absorb and release lithium ions and a binder, making the lithium foil electrically contact the electrode, and in this state, immersing the electrode in an electrolyte containing dissolved lithium salt to ionize lithium and to allow lithium ions to be absorbed into the carbon material; (3) placing an electrode formed by carbon materials that can reversibly absorb and release lithium ions and a binder on the negative electrode side, placing lithium metal on the positive electrode side, immersing it in a non-aqueous electrolyte with lithium salt as the electrolyte, and electrochemically allowing lithium to be absorbed into the carbon material in an ionized state by passing an electric current through it.

[1026] As double-layer capacitors, wound double-layer capacitors, laminated double-layer capacitors, coin-type double-layer capacitors, etc. are commonly known, and the above-mentioned double-layer capacitors can also be made in these forms.

[1027] For example, a wound double-layer capacitor is assembled by winding the positive and negative electrodes of a laminate containing a current collector and an electrode layer through an insulating element to form a wound element, placing the wound element in a housing such as aluminum, filling it with an electrolyte, preferably a non-aqueous electrolyte, and then sealing it with a rubber sealing body.

[1028] As a spacer, spacers made of materials and structures known in the past can be used. Examples include porous polyethylene membranes, polytetrafluoroethylene, polypropylene fibers, glass fibers, and nonwoven fabrics made of cellulose fibers.

[1029] Alternatively, a laminated double-layer capacitor can be manufactured by means of a sheet-shaped positive and negative electrode stacked together with an electrolyte and a separator, or a coin-shaped double-layer capacitor can be manufactured by means of a gasket fixing the positive and negative electrodes together with an electrolyte and a separator.

[1030] The electrolyte of the present invention is useful as an electrolyte for large lithium-ion secondary batteries used in hybrid electric vehicles and distributed power sources, and as an electrolyte for double-layer capacitors.

[1031] Example

[1032] The present invention will then be illustrated by examples, but the present invention is not limited to these examples.

[1033] Synthesis example 1

[1034] <Manufacturing of 2-Fluoro-2-Propylene 2-Fluoroacrylate>

[1035] Triethylamine (2.4 g, 24.0 mmol), 2-fluoro-2-propen-1-ol (1.5 g, 20.0 mmol), and 16 mL of dichloromethane were added to a reaction vessel after nitrogen purging. A solution containing 1.8 g, 20.0 mmol of 2-fluoroacryloyl fluoride dissolved in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was brought to room temperature and stirred for 2 hours, water was added to wash the reaction solution. The solution was then concentrated and distilled to obtain the target product, 2-fluoro-2-propenyl 2-fluoroacrylate (1.6 g, 10.6 mmol, yield 53%).

[1036] Synthesis example 2

[1037] <Manufacturing of 2-Propyryl 2-Fluoroacrylate>

[1038] Triethylamine (2.4 g, 24.0 mmol), propargyl alcohol (1.1 g, 20.0 mmol), and 16 mL of dichloromethane were added to the reaction vessel after nitrogen purging. A solution prepared by dissolving 2-fluoroacryloyl fluoride (1.8 g, 20.0 mmol) in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was brought to room temperature and stirred for 2 hours, water was added to wash the reaction solution, and after concentration, it was distilled to obtain the target product 2-fluoroacrylate 2-propargyl ester (1.6 g, 12.2 mmol, yield 61%).

[1039] Synthesis example 3

[1040] <Manufacturing of 3-trimethylsilyl-2-propynyl 2-fluoroacrylate>

[1041] Triethylamine (2.4 g, 24.0 mmol), 3-trimethylsilyl-2-propyn-1-ol (2.6 g, 20.0 mmol), and 16 mL of dichloromethane were added to the reaction vessel after nitrogen purging. A solution prepared by dissolving 1.8 g, 20.0 mmol of 2-fluoroacryloyl fluoride in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was brought to room temperature and stirred for 2 hours, water was added to wash the reaction solution, and after concentration, it was distilled to obtain the target product, 3-trimethylsilyl-2-propynyl ester of 2-fluoroacrylate (2.0 g, 10.0 mmol, yield 50%).

[1042] Synthesis example 4

[1043] <Production of N,N-diallyl-2-fluoropropenamide>

[1044] Add triethylamine (2.4 g, 24.0 mmol), diallylamine (1.5 g, 20.0 mmol), and 16 mL of dichloromethane to a reaction vessel after purging with nitrogen. Dropwise add a solution prepared by dissolving 2-fluoropropenoyl fluoride (1.8 g, 20.0 mmol) in 8 mL of dichloromethane at 0 °C. After restoring the solution to room temperature and stirring for 2 hours, add water to the reaction solution for washing. After concentration, distillation is carried out to obtain the target product N,N-diallyl-2-fluoropropenamide (2.5 g, 14.8 mmol, yield 74%).

[1045] Synthesis Example 5

[1046] <Production of N-allyl-N-tert-butyl-2-fluoropropenamide>

[1047] Add triethylamine (2.4 g, 24.0 mmol), N-allyl-N-tert-butylamine (2.3 g, 20.0 mmol), and 16 mL of dichloromethane to a reaction vessel after purging with nitrogen. Dropwise add a solution prepared by dissolving 2-fluoropropenoyl fluoride (1.8 g, 20.0 mmol) in 8 mL of dichloromethane at 0 °C. After restoring the solution to room temperature and stirring for 2 hours, add water to the reaction solution for washing. After concentration, distillation is carried out to obtain the target product N-allyl-N-tert-butyl-2-fluoropropenamide (2.0 g, 10.8 mmol, yield 54%).

[1048] Synthesis Example 6

[1049] <Production of N,N-diethyl-2-fluoropropenamide>

[1050] Add triethylamine (2.4 g, 24.0 mmol), diethylamine (1.5 g, 20.0 mmol), and 16 mL of dichloromethane to a reaction vessel after purging with nitrogen. Dropwise add a solution prepared by dissolving 2-fluoropropenoyl fluoride (1.8 g, 20.0 mmol) in 8 mL of dichloromethane at 0 °C. After restoring the solution to room temperature and stirring for 2 hours, add water to the reaction solution for washing. After concentration, distillation is carried out to obtain the target product N,N-diethyl-2-fluoropropenamide (1.7 g, 11.6 mmol, yield 58%).

[1051] Synthesis Example 7

[1052] <Production of 2-fluoro-N,N-diisopropylacrylamide>

[1053] Triethylamine (2.4 g, 24.0 mmol), diisopropylamine (2.0 g, 20.0 mmol), and 16 mL of dichloromethane were added to a reaction vessel after nitrogen purging. A solution containing 1.8 g, 20.0 mmol of 2-fluoroacryloyl fluoride dissolved in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was brought to room temperature and stirred for 2 hours, water was added to wash the reaction solution. The solution was then concentrated and distilled to obtain the target product, 2-fluoro-N,N-diisopropylacrylamide (2.6 g, 15.0 mmol, yield 75%).

[1054] Synthesis example 8

[1055] <Manufacturing of 2-fluoro-1-pyrrolidone-1-yl-propenone>

[1056] Triethylamine (2.4 g, 24.0 mmol), pyrrolidine (1.4 g, 20.0 mmol), and 16 mL of dichloromethane were added to a reaction vessel after nitrogen purging. A solution containing 1.8 g, 20.0 mmol of 2-fluoroacryloyl fluoride dissolved in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was brought to room temperature and stirred for 2 hours, water was added to wash the reaction solution. The solution was then concentrated and distilled to obtain the target product, 2-fluoro-1-pyrrolidine-1-yl-propenone (1.7 g, 11.5 mmol, yield 58%).

[1057] Synthesis example 9

[1058] <Manufacturing of 2-Fluoro-1-piperidin-1-yl-propenone>

[1059] Triethylamine (2.4 g, 24.0 mmol), piperidine (1.7 g, 20.0 mmol), and 16 mL of dichloromethane were added to a reaction vessel after nitrogen purging. A solution containing 1.8 g, 20.0 mmol of 2-fluoroacryloyl fluoride dissolved in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was brought to room temperature and stirred for 2 hours, water was added to wash the reaction solution. The solution was then concentrated and distilled to obtain the target product, 2-fluoro-1-piperidin-1-yl-propenone (1.6 g, 10.0 mmol, yield 50%).

[1060] Synthesis example 10

[1061] <Manufacturing of 2-Fluoro-1-morpholino-4-yl-propenone>

[1062] Triethylamine (2.4 g, 24.0 mmol), morpholine (1.7 g, 20.0 mmol), and 16 mL of dichloromethane were added to a reaction vessel after purging with nitrogen. A solution prepared by dissolving 2-fluoropropionyl fluoride (1.8 g, 20.0 mmol) in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was returned to room temperature and stirred for 2 hours, water was added to the reaction solution for washing. After concentration, distillation was performed to obtain the target product, 2-fluoro-1-morpholin-4-yl-propenone (1.8 g, 11.2 mmol, yield 56%).

[1063] Synthesis Example 11

[1064] <Preparation of N,N-bis(2,2,2-trifluoroethyl)-2-fluoropropenamide>

[1065] Triethylamine (2.4 g, 24.0 mmol), 2,2,2-trifluoroethylamine (2.0 g, 20.0 mmol), and 16 mL of dichloromethane were added to a reaction vessel after purging with nitrogen. A solution prepared by dissolving 2-fluoropropionyl fluoride (1.8 g, 20.0 mmol) in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was returned to room temperature and stirred for 2 hours, water was added to the reaction solution for washing. After concentration, distillation was performed to obtain the target product, N,N-bis(2,2,2-trifluoroethyl)-2-fluoropropenamide (2.7 g, 10.7 mmol, yield 53%).

[1066] Synthesis Example 12

[1067] <Preparation of methyl 2-fluoropropionate>

[1068] Triethylamine (2.4 g, 24.0 mmol), methanol (0.6 g, 20.0 mmol), and 16 mL of dichloromethane were added to a reaction vessel after purging with nitrogen. A solution prepared by dissolving 2-fluoropropionyl fluoride (1.8 g, 20.0 mmol) in 8 mL of dichloromethane was added dropwise at 0 °C. After the solution was returned to room temperature and stirred for 2 hours, water was added to the reaction solution for washing. After concentration, distillation was performed to obtain the target product, methyl 2-fluoropropionate (1.9 g, 18.3 mmol, yield 92%).

[1069] The structures of the compounds obtained above were confirmed by NMR analysis.

[1070] (Preparation of electrolyte)

[1071] Examples 1 to 8

[1072] A basic electrolyte was prepared by adding LiPF6 to a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (volume ratio 30:70) at a concentration of 1.0 mol / L. Then, 2-fluoro-2-propenyl 2-fluoroacrylate was added to this basic electrolyte to the concentrations shown in Table 1 to obtain a non-aqueous electrolyte. The concentrations of each added compound in the tables represent proportions relative to the final electrolyte obtained.

[1073] Example 9

[1074] In Example 4, 2-propynyl 2-fluoroacrylate was added instead of 2-fluoro-2-propenyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1075] Example 10

[1076] In Example 4, 3-trimethylsilyl-2-propynyl 2-fluoroacrylate was added instead of 2-fluoro-2-propynyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1077] Example 11

[1078] In Example 4, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1079] Example 12

[1080] In Example 4, N-allyl-N-tert-butyl-2-fluoroacrylamide was added instead of 2-fluoroacrylic acid 2-fluoro-2-propylene ester to obtain a non-aqueous electrolyte.

[1081] Example 13

[1082] In Example 4, N,N-diethyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1083] Example 14

[1084] In Example 4, 2-fluoro-N,N-diisopropylacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1085] Example 15

[1086] In Example 4, 2-fluoro-1-pyrrolidone-1-yl-propenone was added instead of 2-fluoro-2-propenyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1087] Example 16

[1088] In Example 4, 2-fluoro-1-piperidin-1-yl-propenone was added instead of 2-fluoro-2-propenyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1089] Example 17

[1090] In Example 4, 2-fluoro-1-morpholino-4-yl-propenone was added instead of 2-fluoro-2-propenyl acrylate to obtain a non-aqueous electrolyte.

[1091] Example 18

[1092] In Example 4, N,N-bis(2,2,2-trifluoroethyl)-2-fluoroacrylamide was added instead of 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1093] Example 19

[1094] In Example 4, methyl 2-fluoroacrylate was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1095] Example 20

[1096] A basic electrolyte was prepared by adding LiPF6 to a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio 30:70) at a concentration of 1.0 mol / L. Then, 2-fluoro-2-propenyl 2-fluoroacrylate was added to this basic electrolyte to the concentrations listed in Table 1 to obtain a non-aqueous electrolyte.

[1097] Example 21

[1098] A basic electrolyte was prepared by adding LiPF6 to a mixture of ethylene carbonate (EC) and ethyl propionate (volume ratio 30:70) at a concentration of 1.0 mol / L. Then, 2-fluoro-2-propenyl 2-fluoroacrylate was added to this basic electrolyte to the concentrations listed in Table 1 to obtain a non-aqueous electrolyte.

[1099] Example 22

[1100] In Example 21, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1101] Comparative Example 1

[1102] In Example 1, a non-aqueous electrolyte was prepared without the addition of 2-fluoro-2-propene 2-fluoroacrylate.

[1103] Comparative Example 2

[1104] In Example 4, methyl acrylate was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1105] Comparative Example 3

[1106] In Example 4, N,N-dimethylacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1107] Comparative Example 4

[1108] In Example 4, N-allylacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1109] (Fabrication of aluminum laminated lithium-ion secondary batteries)

[1110] [The production of the positive electrode]

[1111] Li(Ni) will be used as the positive electrode active material 1 / 3 Mn 1 / 3 Co 1 / 3 O2 90% by mass, acetylene black (5% by mass) as a conductive material, and polyvinylidene fluoride (PVdF) (5% by mass) as a binder are mixed in N-methylpyrrolidone solvent and slurried. The resulting slurry is coated on one side of an aluminum foil with a thickness of 15 μm pre-coated with conductive additives, dried, and rolled using a forming machine to cut it into shapes with an active material layer of 50 mm wide and 30 mm long, and an uncoated portion of 5 mm wide and 9 mm long, to form the positive electrode.

[1112] [Making the negative electrode]

[1113] To 98 parts by weight of carbonaceous material (graphite), 1 part by weight of an aqueous dispersion of sodium carboxymethyl cellulose (1% by weight) and 1 part by weight of an aqueous dispersion of styrene-butadiene rubber (50% by weight) were added as a thickener and binder, and the mixture was slurried using a disperser. The resulting slurry was coated onto a 10 μm thick copper foil and dried. After calendering using a molding machine, it was cut into shapes with an active material layer of 52 mm width and 32 mm length, and an uncoated portion of 5 mm width and 9 mm length, to form a negative electrode.

[1114] [Fabrication of aluminum laminated battery cells]

[1115] With the positive and negative electrodes facing each other through a 20μm thick microporous polyethylene membrane (separator), the above-mentioned non-aqueous electrolyte is injected. After the non-aqueous electrolyte fully permeates the separator, it is sealed, pre-charged, and aged to produce a lithium-ion secondary battery.

[1116] (Determination of battery characteristics)

[1117] [Initial Feature Evaluation]

[1118] The lithium-ion secondary battery, manufactured as described above, is held in a plate clamp and pressurized. It is then charged at 25°C with a constant current of 0.2C to 4.2V, followed by a constant current discharge of 0.2C to 3.0V. This process is repeated for two cycles to stabilize the battery. In the third cycle, the battery is charged at a constant current of 0.2C to 4.2V, then charged at a constant voltage of 4.2V until the current reaches 0.05C, and then discharged at a constant current of 0.2C to 3.0V. Then, in the fourth cycle, the battery is charged at a constant current of 0.2C to 4.2V, then charged at a constant voltage of 4.2V until the current reaches 0.05C, and then discharged at a constant current of 0.2C to 3.0V. The initial discharge capacity is calculated. Then, the battery is charged at a constant current of 0.2C to 4.2V, then charged at a constant voltage of 4.2V until the current reaches 0.05C.

[1119] Here, 1C represents the current value at which the battery's base capacity is discharged in 1 hour, 5C represents 5 times that current value, 0.1C represents 1 / 10 of that current value, and 0.2C represents 1 / 5 of that current value.

[1120] [High-Temperature Storage Test]

[1121] After the initial characteristic evaluation, the secondary batteries were stored at 85°C for 36 hours. After the batteries were fully cooled, their volume was measured using the Archimedes method, and the amount of gas produced was determined from the volume change before and after storage. Next, the batteries were discharged to 3V at 0.5C at 25°C, and the residual capacity after high-temperature storage was measured. The capacity retention rate (%) was calculated based on the following formula.

[1122] (Residual Capacity) / (Initial Discharge Capacity) × 100 = Capacity Retention Rate (%)

[1123] The results are shown in Table 1.

[1124] [High-Temperature Cycling Test]

[1125] With the lithium-ion secondary battery manufactured above held in a plate clamp and pressurized, it is charged at 45°C using a constant current-constant voltage (CC / CV charging) at a current equivalent to 1C (0.1C cutoff) to 4.2V. Then, it is discharged at a constant current of 1C to 3V, which is considered one cycle. The initial discharge capacity is calculated from the discharge capacity of the third cycle. Here, 1C represents the current value at which the battery's reference capacity is discharged in 1 hour; for example, 0.2C represents 1 / 5 of that current value. The cycle is repeated, and the discharge capacity is measured after 200 cycles. The ratio of the discharge capacity after 200 cycles to the initial discharge capacity is calculated and taken as the cycle capacity retention rate (%).

[1126] (Discharge capacity after 200 cycles ÷ (initial discharge capacity) × 100 = Capacity retention rate (%))

[1127] The results are shown in Table 1.

[1128] (Preparation of electrolyte)

[1129] Example 23

[1130] A basic electrolyte was prepared by adding LiPF6 to a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (volume ratio 30:70) at a concentration of 1.2 mol / L. Then, 2-fluoro-2-propenyl 2-fluoroacrylate and vinylene carbonate (VC) were added to this basic electrolyte to achieve the contents described in Table 2, resulting in a non-aqueous electrolyte.

[1131] Example 24

[1132] In Example 23, lithium bis(oxalatoborate) (LiBOB) was added instead of vitamin C to achieve the amounts described in Table 2, resulting in a non-aqueous electrolyte.

[1133] Example 25

[1134] In Example 23, lithium difluorophosphate (LiPO2F2) was added instead of VC to achieve the amounts described in Table 2, resulting in a non-aqueous electrolyte.

[1135] Example 26

[1136] In Example 23, lithium fluorosulfonate (FSO3Li) was added instead of VC to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1137] Example 27

[1138] In Example 23, ethyl lithium sulfate (C2H5OSO3Li) was added instead of VC in such a manner as to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1139] Example 28

[1140] In Example 23, fluoroethylene carbonate (FEC) was added instead of VC in such a manner as to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1141] Example 29

[1142] In Example 23, a non-aqueous electrolyte was obtained by adding 4-(2,2,3,3,3-pentafluoropropyl)-[1,3]dioxapentane-2-one (CF3CF2CH2-EC) instead of VC in such a manner as to achieve the amounts described in Table 2.

[1143] Example 30

[1144] In Example 23, 2-propynyl 2-fluoroacrylate was added instead of 2-fluoro-2-propenyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1145] Example 31

[1146] In Example 23, 3-trimethylsilyl-2-propynyl 2-fluoroacrylate was added instead of 2-fluoro-2-propynyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1147] Example 32

[1148] In Example 23, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1149] Example 33

[1150] In Example 24, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1151] Example 34

[1152] In Example 25, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1153] Example 35

[1154] In Example 26, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1155] Example 36

[1156] In Example 27, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1157] Example 37

[1158] In Example 28, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1159] Example 38

[1160] In Example 29, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1161] Example 39

[1162] In Example 23, N-allyl-N-tert-butyl-2-fluoroacrylamide was added instead of 2-fluoroacrylic acid 2-fluoro-2-propylene ester to obtain a non-aqueous electrolyte.

[1163] Example 40

[1164] In Example 23, N,N-diethyl-2-fluoroacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1165] Example 41

[1166] In Example 23, 2-fluoro-N,N-diisopropylacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1167] Example 42

[1168] In Example 23, 2-fluoro-1-pyrrolidone-1-yl-propenone was added instead of 2-fluoro-2-propenyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1169] Example 43

[1170] In Example 23, 2-fluoro-1-piperidin-1-yl-propenone was added instead of 2-fluoro-2-propenyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1171] Example 44

[1172] In Example 23, 2-fluoro-1-morpholino-4-yl-propenone was added instead of 2-fluoro-2-propenyl 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1173] Example 45

[1174] In Example 23, N,N-bis(2,2,2-trifluoroethyl)-2-fluoroacrylamide was added instead of 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1175] Example 46

[1176] In Example 23, methyl 2-fluoroacrylate was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1177] Example 47

[1178] A basic electrolyte was prepared by adding LiPF6 to a mixture of EC, EMC, and ethyl propionate (volume ratio 30:40:30) at a concentration of 1.2 mol / L. Then, 2-fluoro-2-propene 2-fluoroacrylate and vinylene carbonate (VC) were added to this basic electrolyte to the amounts described in Table 2 to obtain a non-aqueous electrolyte.

[1179] Example 48

[1180] In Example 47, lithium bis(oxalateborate)borate (LiBOB) was added instead of vitamin C to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1181] Example 49

[1182] In Example 47, lithium difluorophosphate (LiPO2F2) was added instead of VC to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1183] Example 50

[1184] In Example 47, lithium fluorosulfonate (FSO3Li) was added instead of VC to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1185] Example 51

[1186] In Example 47, ethyl lithium sulfate (C2H5OSO3Li) was added instead of VC in such a manner as to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1187] Example 52

[1188] In Example 47, fluoroethylene carbonate (FEC) was added instead of VC to achieve the content described in Table 2, resulting in a non-aqueous electrolyte.

[1189] Example 53

[1190] In Example 47, 4-(2,2,3,3,3-pentafluoropropyl)-[1,3]dioxapentane-2-one (CF3CF2CH2-EC) was added instead of VC to obtain a non-aqueous electrolyte in order to achieve the content described in Table 2.

[1191] Examples 54-60

[1192] In Examples 47-53, N,N-diallyl-2-fluoroacrylamide was added instead of 2-fluoroacrylic acid 2-fluoro-2-propylene ester to obtain a non-aqueous electrolyte.

[1193] Examples 61-67

[1194] In Examples 47-53, 2-fluoro-1-morpholino-4-yl-propenone was added instead of 2-fluoro-2-propenyl acrylate to obtain a non-aqueous electrolyte.

[1195] Comparative Example 5

[1196] In Example 23, a non-aqueous electrolyte was prepared without the addition of 2-fluoro-2-propene 2-fluoroacrylate.

[1197] Comparative Example 6

[1198] In Example 28, a non-aqueous electrolyte was prepared without the addition of 2-fluoro-2-propene 2-fluoroacrylate.

[1199] Comparative Example 7

[1200] In Example 23, methyl acrylate was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1201] Comparative Example 8

[1202] In Example 23, N,N-dimethylacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1203] Comparative Example 9

[1204] In Example 23, N-allylacrylamide was added instead of 2-fluoro-2-propene 2-fluoroacrylate to obtain a non-aqueous electrolyte.

[1205] Comparative Example 10

[1206] In Example 47, a non-aqueous electrolyte was prepared without the addition of 2-fluoro-2-propene 2-fluoroacrylate.

[1207] Comparative Example 11

[1208] In Example 52, a non-aqueous electrolyte was prepared without the addition of 2-fluoro-2-propene 2-fluoroacrylate.

[1209] (Fabrication of aluminum laminated lithium-ion secondary batteries)

[1210] Lithium-ion secondary batteries were manufactured in the same manner as in Example 1, except that the non-aqueous electrolytes described in Examples 23-67 and Comparative Examples 5-11 were used.

[1211] (Determination of battery characteristics)

[1212] [Initial Feature Evaluation]

[1213] The lithium secondary battery, manufactured as described above, was held in a plate clamp and pressurized. It was then charged at 25°C with a constant current of 0.2C to 4.2V, followed by a constant current discharge of 0.2C to 3.0V. This process was repeated for two cycles to stabilize the battery. In the third cycle, the battery was charged at a constant current of 0.2C to 4.2V, then charged at a constant voltage of 4.2V until the current reached 0.05C, and then discharged at a constant current of 0.2C to 3.0V. Then, in the fourth cycle, the battery was charged at a constant current of 0.2C to 4.2V, then charged at a constant voltage of 4.2V until the current reached 0.05C, and then discharged at a constant current of 0.2C to 3.0V. The initial discharge capacity was calculated. Then, the battery was charged at a constant current of 0.2C to 4.2V, then charged at a constant voltage of 4.2V until the current reached 0.05C, and the initial resist...

Claims

1. A compound, characterized in that, It can be represented by the following general formula (12): ； In the formula, R 112 and R 113 : (i) Independently comprising an unfluorinated alkyl group having 1 to 7 carbon atoms, a fluorinated alkyl group having 1 to 5 carbon atoms, an alkenyl group having 3 to 7 carbon atoms (fluorinated or unfluorinated), or an alkynyl group having 3 to 7 carbon atoms (fluorinated or unfluorinated), and R 112 and R 113 At least one of them is isopropyl, tert-butyl, a fluoroalkyl group having 1 to 5 carbon atoms, an alkenyl group having 3 to 7 carbon atoms (fluorinated or unfluorinated), or an alkynyl group having 3 to 7 carbon atoms (fluorinated or unfluorinated); or (ii) Hydrocarbon groups with 3 to 5 carbon atoms that form 5- or 6-membered heterocycles with nitrogen atoms for mutual linkage.

2. The compound according to claim 1, wherein, R 112 and / or R 113 The structure contains at least one of O, S, and N, or R. 112 and / or R 113 The structure does not contain any of the elements O, S, and N.

3. Compounds represented by any of the following formulas: 。

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