Fluorine-containing carboxylate compound

Abstract

This invention provides a novel method for manufacturing fluorinated carboxylate compounds, for producing formula (P1): (B 1f ) mp (A) 1 ) np [B] 1f RfCOO; Rf is a hydrocarbon group having one or more fluorine atoms; A 1 It is a group other than H; mp is (A 1 The valence of () × np and is 1 or 2; np is mp / (A 1 The valence of A is 1; 1 The method of manufacturing a compound having a valence of 1 or 2 includes: making formula (S1): (B 1f (R) 1 ) [R 1 The compound shown is an organic group and is related to formula (S2): (A 1 ) ms2 (B) 2 ) ns2 [B] 2 It is OH, CO3 or HCO3; ms2 is (B 2 (valence) × ns2 / (A) 1 The valence of ns is 1 or 2; ns2 is (A 1 (value) × ms² / (B) 2 The reaction of the compound or its hydrate shown in the figure (with a valence of 1 or 2) is a step A.

Description

[0001] This case is filed on the date of application. September 6, 2021 Application number is 202180061692.9 (PCT / JP2021 / 032577) A divisional application of the patent application entitled "Fluorocarboxylate Compound". Technical Field

[0002] This invention relates to fluorinated carboxylate compounds, etc. Background Technology

[0003] Fluorocarboxylate compounds are useful compounds used in electrochemical devices, etc. (Patent Document 1).

[0004] The method of synthesizing lithium fluorinated carboxylate by reacting a fluorinated carboxyl halide with lithium hydroxide or by reacting a fluorinated carboxylic acid with lithium hydroxide or lithium carbonate is known (Patent Document 2).

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2004-22379 Patent Document 2: Japanese Patent Application Publication No. 2011-93808 Summary of the Invention

[0006] The problem that the invention aims to solve In existing methods for manufacturing fluorinated carboxylate compounds, as described above, water is generated as a byproduct and is difficult to remove.

[0007] The purpose of this invention is to provide a new method for manufacturing fluorinated carboxylate compounds (preferably fluorinated carboxylate compounds with low moisture content).

[0008] Technical solutions for solving the problem The above-mentioned problem is solved by the following manufacturing method. This manufacturing method is a method for manufacturing the compound shown in formula (P1), which includes step A of reacting the compound shown in formula (S1) with the compound shown in formula (S2) or their hydrates.

[0009] Formula (P1): (B) 1f ) mp (A) 1 ) np [In the formula,] B 1f For RfCOO, Rf is a hydrocarbon group having one or more fluorine atoms. A 1 Groups other than H mp is (A 1 (value) × np / (B) 1The valence number is a number that is either 1 or 2. np is (B) 1 (value) × mp / (A) 1 The valence number is 1. A 1 The price is 1 or 2. B 1f The value is 1. Formula (S1): (B) 1f (R) 1 ) [In the formula,] B 1f The meaning is the same as above. R 1 It is an organic group. But R 1 With A 1 They are different functional groups. Formula (S2): (A) 1 ) ms2 (B) 2 ) ns2 [In the formula,] A 1 The meaning is the same as above. B 2 It can be OH, CO3, or HCO3. ms2 is (B 2 (valence) × ns2 / (A) 1 The valence number is a number that is either 1 or 2. ns2 is (A 1 (value) × ms² / (B) 2 [The value of the valence (i.e., 1 or 2).] The present invention provides the following embodiments, etc.

[0010] Item 1. A method for manufacturing a compound of formula (P1), comprising step A of reacting the compound of formula (S1) with the compound of formula (S2) or their hydrates.

[0011] Formula (P1): (B) 1f ) mp (A) 1 ) np [In the formula,] B 1f For RfCOO, Rf is a hydrocarbon group having one or more fluorine atoms. A 1 Groups other than H mp is (A 1 (value) × np / (B)1f The valence number is a number that is either 1 or 2. np is (B) 1f (value) × mp / (A) 1 The valence number is 1. A 1 The price is 1 or 2. B 1f The value is 1. Formula (S1): (B) 1f (R) 1 ) [In the formula,] B 1f The meaning is the same as above. R 1 It is an organic group. But R 1 With A 1 They are different functional groups. Formula (S2): (A) 1 ) ms2 (B) 2 ) ns2 [In the formula,] A 1 The meaning is the same as above. B 2 It can be OH, CO3, or HCO3. ms2 is (B 2 (valence) × ns2 / (A) 1 The valence number is a number that is either 1 or 2. ns2 is (A 1 (value) × ms² / (B) 2 [The value of the valence (i.e., 1 or 2).] Item 2. The manufacturing method as described in Item 1, wherein A 1 It consists of metal atoms or ammonium.

[0012] Item 3. The manufacturing method as described in Item 1 or Item 2 further includes a step B in which the compound of formula (P2) generated as a byproduct in step A is removed.

[0013] Formula (P2): (R) 1 ) op (B) 2 ) [In the formula,] B 2 and R 1 The meaning is the same as above. op is (B) 2 (price) / (R) 1 The valence (of the valence) is a number that is either 1 or 2. Item 4. The manufacturing method as described in any one of Items 1 to 3, wherein Rf is a C1-6 alkyl group having one or more fluorine atoms.

[0014] Item 5. The manufacturing method as described in any one of Items 1 to 4, wherein Rf is a C1-3 alkyl group having two or more fluorine atoms.

[0015] Item 6. The manufacturing method as described in any one of Items 1 to 5, wherein A 1 It consists of alkali metal atoms.

[0016] Item 7. The manufacturing method as described in any one of Items 1 to 6, wherein A 1 For Li.

[0017] Item 8. The manufacturing method as described in any one of Items 1 to 7, wherein B 2 It is OH.

[0018] Item 9. An additive for electrochemical devices, comprising a compound of formula (P1A) and water in an amount of 0 to 50,000 ppm by mass relative to the compound of formula (P1A).

[0019] Formula (P1A): RfCOOA d [In the formula,] Rf is an organic group having one or more fluorine atoms. A d These are metal atoms. Item 10. An electrolyte containing the additives for electrochemical devices described in Item 9.

[0020] Item 11. An electrochemical device having the electrolyte described in Item 10.

[0021] Item 12. A lithium-ion secondary battery having the electrolyte described in item 10.

[0022] Item 13. A compound represented by formula (P1A) having a water content of less than 50,000 ppm by mass.

[0023] Formula (P1A): RfCOOA d [In the formula,] Rf is an organic group having one or more fluorine atoms. A d [These are Li atoms.] Item 14. A composition comprising a compound of formula (P1A) and water at a mass concentration of less than 50,000 ppm relative to the compound of formula (P1).

[0024] Formula (P1A): RfCOOA d [In the formula,] Rf is an organic group having one or more fluorine atoms. A d [These are Li atoms.] Item 15. The compound as described in Item 13, which is manufactured by any one of the manufacturing methods described in Items 1 to 8.

[0025] Item 16. The composition as described in Item 14, manufactured by any one of the manufacturing methods described in Items 1 to 8.

[0026] Invention Effects In the manufacturing method of one embodiment of the present invention, water is not generated as a byproduct. Therefore, it is advantageous to provide industrially fluorinated carboxylate compounds, preferably with low moisture content, and more preferably with substantially no moisture content.

[0027] An electrochemical device or lithium-ion secondary battery according to one embodiment of the present invention, which uses an electrolyte containing the fluorinated carboxylate compound, has industrial advantages [lower manufacturing cost and higher performance (e.g., higher cycle capacity retention or lower resistance increase rate). Detailed Implementation

[0028] the term Unless otherwise specified, the symbols and abbreviations in this specification may be understood, in the context of this specification, as commonly used in the technical field to which this invention pertains.

[0029] In this specification, the use of the phrase "contains" is intended to include both the phrase "essentially constitutes..." and the phrase "consisting only of...".

[0030] Unless otherwise specified, the procedures, treatments or operations described in this manual may be performed at room temperature.

[0031] In this instruction manual, room temperature may refer to a temperature in the range of 10 to 40°C.

[0032] In this specification, the symbol "C" is used. n -C m (where n and m are numbers) as commonly understood by those skilled in the art, means that the number of carbon atoms is n or more and m or less.

[0033] In this specification, unless otherwise specified, examples of "halogenated" include fluorinated, chlorinated, brominated, and iodinated.

[0034] In this specification, unless otherwise specified, examples of "halogen (atom)" include fluorine (atom), chlorine (atom), bromine (atom) and iodine (atom).

[0035] In this specification, "organic group" means a group containing one or more carbon atoms (or a group formed by removing one hydrogen atom from an organic compound).

[0036] In this specification, unless otherwise specified, "heteroatom" may refer to an atom other than hydrogen and carbon.

[0037] In this specification, unless otherwise specified, examples of "heteroatoms" may include nitrogen atoms, oxygen atoms, and sulfur atoms.

[0038] In this specification, unless otherwise specified, "organic group" means a group whose constituent atoms contain one or more carbon atoms.

[0039] In this specification, unless otherwise specified, examples of "organic groups" include: (1) Hydrocarbon group (which may have more than one substituent). (2) A group in which one or more heteroatoms are inserted into a hydrocarbon group (which may have more than one substituent) [in this specification, it is sometimes referred to as "heterohydrocarbon group"].

[0040] Examples of such substituents include halogen, nitro, cyano, oxy, thioxo group, sulfo group, sulfamoyl group, sulfinyl group, and sulfenamoyl group.

[0041] In this specification, unless otherwise specified, "hydrocarbon (group)" refers to a group whose constituent atoms contain one or more carbon atoms and one or more hydrogen atoms, preferably a group whose constituent atoms consist of only one or more carbon atoms and one or more hydrogen atoms.

[0042] Examples of “(1) hydrocarbon group” above include aliphatic hydrocarbon groups (e.g., benzyl) that can be replaced by one or more aromatic hydrocarbon groups, and aromatic hydrocarbon groups (aryl in the narrow sense) that can be replaced by one or more aliphatic hydrocarbon groups.

[0043] In this specification, (hetero)aryl includes aryl in the narrow sense and heteroaryl.

[0044] Examples of “(2) groups with one or more heteroatoms inserted into the hydrocarbon group” (heterohydrocarbon group) include 5-6 member heteroaryl groups and groups that condense the benzene ring with the 5-6 member heteroaryl group, including alkoxy groups, ester groups, ether groups and heterocyclic groups.

[0045] In this specification, unless otherwise specified, "aliphatic hydrocarbon (base)" can be linear, branched, cyclic, or a combination thereof.

[0046] In this specification, unless otherwise specified, "aliphatic hydrocarbons (bases)" can be saturated or unsaturated.

[0047] In this specification, unless otherwise specified, examples of "aliphatic hydrocarbons (groups)" include alkyl, alkenyl, ynyl and cycloalkyl groups.

[0048] In this specification, unless otherwise specified, examples of "alkyl" include alkyl groups with 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, and hexyl, which are straight-chain or branched.

[0049] In this specification, unless otherwise specified, examples of "alken(yl)" include alkenyl groups with 1 to 10 carbon atoms that are either straight-chain or branched (e.g., vinyl, 1-propenyl, isopropenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-ethyl-1-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 4-methyl-3-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, and 5-hexenyl, etc.).

[0050] In this specification, unless otherwise specified, examples of "alkynyl" include linear or branched alkynyl groups with 2 to 6 carbon atoms (e.g., ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl and 5-hexynyl).

[0051] In this specification, unless otherwise specified, examples of "cycloalkyl" include cycloalkyl groups having 3 to 8 carbon atoms (e.g., cyclopentyl, cyclohexyl, and cycloheptyl).

[0052] In this specification, unless otherwise specified, "aromatic hydrocarbon (group) [aromatic (group)]" can be exemplified by phenyl, naphthyl, phenanthryl, anthraceneyl, and pyrene.

[0053] In this specification, unless otherwise specified, the term "arane(yl)" as commonly understood means an alkyl group substituted with one aryl group.

[0054] In this specification, unless otherwise specified, "alkoxy(group)" can be, for example, a group represented by RO- (where R is an alkyl group).

[0055] In this specification, unless otherwise specified, "ester group" refers to an organic group having an ester bond [i.e., -CO2- (i.e., -C(=O)-O- or -O-C(=O)-).

[0056] Examples of ester groups include groups represented by the formula: RCO2- (where R is an alkyl group) and groups represented by the formula: Ra-CO2-Rb- (where Ra is an alkyl group and Rb is an alkylene group).

[0057] In this specification, unless otherwise specified, "ether group" refers to a group having an ether bond (-O-).

[0058] Examples of "ether group" include polyether group.

[0059] Examples of polyether groups include those represented by the formula: Ra-(O-Rb)n- (where Ra is an alkyl group, Rb is the same or different each time it appears, is an alkylene group, and n is an integer greater than or equal to 1).

[0060] An alkylene group is a divalent group formed by removing one hydrogen atom from the aforementioned alkyl group.

[0061] Examples of "ether groups" also include hydrocarbon ether groups.

[0062] A hydrocarbon ether group refers to a hydrocarbon group having one or more ether bonds. "A hydrocarbon group having one or more ether bonds" can also refer to a hydrocarbon group with one or more ether bonds inserted into it. Examples include benzyloxy groups.

[0063] Examples of "hydrocarbon groups having more than one ether bond" include alkyl groups having more than one ether bond.

[0064] "An alkyl group having one or more ether bonds" can be an alkyl group with one or more ether bonds inserted. In this specification, such a group is sometimes referred to as an alkyl ether group.

[0065] In this specification, unless otherwise specified, "acyl" includes the alkanoyl group. In this specification, unless otherwise specified, "alkanoyl" is, for example, a group represented by RcCO- (where Rc is an alkyl group).

[0066] In this specification, examples of "5- to 6-membered heteroaryl groups" include: 5- to 6-membered heteroaryl groups having one or more (e.g., one, two, or three) heteroatoms selected from oxygen, sulfur, and nitrogen as cyclic atoms [e.g., pyrrole (e.g., 1-pyrrole, 2-pyrrole, 3-pyrrole), furanyl (e.g., 2-furanyl, 3-furanyl), thiophene (e.g., 2-thiophene, 3-thiophene), pyrazolyl (e.g., 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl), imidazole (e.g., 1-imidazole, 2-imidazole, 4-imidazole), isoxazolyl (e.g., 3-isooxazolyl, 4-isooxazolyl, 5-isooxazolyl), oxazolyl (e.g., 2-oxazolyl, 4-oxazolyl, 5-oxazolyl)]. Isothiazolyl (e.g., 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl), thiazolyl (e.g., 2-thiazolyl, 4-thiazolyl, 5-thiazolyl), triazolyl (e.g., 1,2,3-triazol-4-yl, 1,2,4-triazol-3-yl), oxadiazolyl (e.g., 1,2,4-oxadiazol-3-yl, 1,2,4-oxadiazol-5-yl), thiazolyl (e.g., 1,2,4-thiadiazol-3-yl, 1,2,4-thiadiazol-5-yl), tetrazolyl, pyridyl (e.g., 2-pyridyl, 3-pyridyl, 4-pyridyl), pyrazinyl (e.g., 3-pyrazinyl, 4-pyrazinyl), pyrimidinyl (e.g., 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl), and pyrazinyl, etc.

[0067] Methods for manufacturing compounds Process A One embodiment of the present invention provides a manufacturing method for producing a compound of formula (P1), comprising step A of reacting the compound of formula (S1) with the compound of formula (S2) or their hydrates.

[0068] Formula (P1): (B) 1f ) mp (A) 1 ) np [In the formula,] B 1f For RfCOO, Rf is a hydrocarbon group having one or more fluorine atoms. A 1 Groups other than H mp is (A 1 (value) × np / (B) 1 The valence number is a number that is either 1 or 2. np is (B) 1 (value) × mp / (A) 1 The valence number is 1. A 1 The price is 1 or 2. B 1f The value is 1. Formula (S1): (B) 1f (R) 1 ) [In the formula,] B 1f The meaning is the same as above. R 1 It is an organic group. But R 1 With A 1 They are different functional groups. Formula (S2): (A) 1 ) ms2 (B) 2 ) ns2 [In the formula,] A 1 The meaning is the same as above. B 2 It can be OH, CO3, or HCO3. ms2 is (B 2 (valence) × ns2 / (A) 1 The valence number is a number that is either 1 or 2. ns2 is (A 1 (value) × ms² / (B) 2 [The value of the valence (i.e., 1 or 2).] From the perspectives of reaction addition rate, target product selectivity, and yield, A is preferred. 1 It consists of metal atoms or ammonium.

[0069] From the perspectives of reaction addition rate, target product selectivity, and yield, A is preferred. 1 It consists of alkali metal atoms.

[0070] From the perspectives of reaction addition rate, target product selectivity, and yield, the preferred metal atom is an alkali metal atom.

[0071] From the viewpoints of reaction addition rate, target analyte selectivity, and yield, it is preferable that the metal atom be Li, Na, or K.

[0072] From the perspectives of reaction addition rate, target analyte selectivity, and yield, the metal atom is further preferred to be Li.

[0073] From the perspectives of reaction addition rate, target product selectivity, and yield, Rf is preferably an alkyl group having one or more fluorine atoms.

[0074] From the viewpoints of reaction addition rate, target product selectivity, and yield, it is more preferable that Rf is a C1-6 alkyl group having one or more fluorine atoms.

[0075] From the perspectives of reaction addition rate, target product selectivity, and yield, Rf is further preferred to be a C1-3 alkyl group having two or more fluorine atoms.

[0076] From the perspectives of reaction addition rate, target product selectivity, and yield, option B is preferred. 2 It is OH.

[0077] In equation (P1), mp is (A 1 (value of) × np / (B) 1 The valence of np is a number that is either 1 or 2, and np is (B 1 (price) × mp / (A) 1 The valence of (A) is a number that is 1. That is, mp is (A) 1 (value) / (B) 1 The valence of np is 1 or 2, and np is 1.

[0078] In equation (S2), ms2 is (B 2 (valence) × ns2 / (A) 1 The valence of ns is a number that is either 1 or 2, and ns2 is (A 1 (value) × ms² / (B) 2 The valence of the valence is 1 or 2.

[0079] Process A can be carried out using techniques commonly used in chemical reactions.

[0080] From the viewpoints of reaction addition rate, target selection rate, yield, etc., it is preferable, for example, to add compound (S2) to compound (S1) placed in the reactor in one or several batches.

[0081] Furthermore, from the viewpoints of reaction addition rate, target selection rate, yield, etc., it is preferable, for example, to add compound (S1) to compound (S2) placed in the reactor in one or several batches.

[0082] From the viewpoint that fluorinated carboxylate compounds with low moisture content are readily available, and preferably fluorinated carboxylate compounds that are substantially free of moisture, it is preferable to use the anhydrous salt of compound (S2). The anhydrous salt of compound (S2) can be a commercially available product, or it can be used after dehydrating (anhydrousizing) compound (S2) according to known methods.

[0083] Solvents can be used in process A.

[0084] From the viewpoint that fluorinated carboxylate compounds with low water content are readily available, and preferably fluorinated carboxylate compounds that are substantially free of water, any solvent other than water can be used as the solvent.

[0085] Specific examples of this solvent include: (1) Alcohol solvents [e.g., methanol, ethanol, n-propanol, isopropanol, n-butanol, pentanol, hexanol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, trimethylene glycol, hexanetriol]; (2) Non-aromatic hydrocarbon solvents [e.g., pentane, hexane, heptane, octane, cyclohexane, decahydronaphthalene, n-decane, isododecane, tridecane]; (3) Aromatic hydrocarbon solvents [e.g., benzene, toluene, xylene, tetrahydronaphthalene, o-dimethoxybenzene, ethylbenzene, diethylbenzene, methylnaphthalene, anisole, phenethyl ether nitrobenzene, o-nitrotoluene, mesitylene, indene, diphenyl sulfide, anisole, acetone]; (4) Ketone solvents [e.g., acetone, methyl ethyl ketone, diethyl ketone, hexanone, methyl isobutyl ketone, heptanone, diisobutyl ketone, acetylacetone, methyl hexanone, acetophenone, cyclohexanone, diacetone alcohol, phenylacetone, isophorone]; (5) Halogenated hydrocarbon solvents [e.g., dichloromethane, chloroform, chlorobenzene]; (6) Ether solvents [e.g., diethyl ether, tetrahydrofuran (THF), diisopropyl ether, methyl tert-butyl ether (MTBE), dioxane, dimethoxyethane, diethylene glycol dimethyl ether, anisole, phenethyl ether, 1,1-dimethoxycyclohexane, diisopentyl ether, cyclopentyl methyl ether (CPME)]; (7) Ester solvents [e.g., ethyl acetate, isopropyl acetate, diethyl malonate, 3-methoxy-3-methylbutyl acetate, γ-butyrolactone, ethylene carbonate, propylene carbonate, dimethyl carbonate, α-acetyl-γ-butyrolactone]; (8) Nitrile solvents [e.g., acetonitrile, benzonitrile]; (9) Sulfoxide solvents [e.g., dimethyl sulfoxide, sulfolane]; and (10) Amide solvents [e.g., N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methylpyrrolidone (NMP), 1,3-dimethyl-2-imidazolinone (DMI), N,N-dimethylacrylamide, N,N-dimethylacetylacetamide (DMA), N,N-diethylformamide, N,N-diethylacetamide].

[0086] These solvents can be used alone or in combination of two or more.

[0087] From the viewpoints of reaction addition rate, target product selectivity, yield, etc., the temperature of process A is preferably below 120°C, more preferably below 110°C, even more preferably below 100°C, even more preferably below 90°C, and particularly preferably below 80°C.

[0088] From the viewpoints of reaction addition rate, target product selectivity, and yield, the temperature of process A is preferably -50°C or higher, more preferably -20°C or higher, even more preferably -10°C or higher, even more preferably 0°C or higher, and particularly preferably 5°C or higher.

[0089] There is no specific time limit for process A; for example, it can be carried out until the reaction is complete.

[0090] The conditions for process A can be achieved, for example, by using a pressure vessel (e.g., an autoclave) to achieve high temperature and high pressure. In this case, the reaction time can be shortened accordingly.

[0091] Process A can be carried out in an inert gas atmosphere (such as nitrogen).

[0092] Process A can be carried out in an atmospheric atmosphere.

[0093] From the viewpoint that fluorinated carboxylate compounds with low moisture content are readily available, and preferably fluorinated carboxylate compounds that are substantially free of moisture, it is preferable to carry out the process in an inactive gas atmosphere.

[0094] After step A and before step B, which removes the compound (P2) of formula (P2) generated as a byproduct in step A, treatments such as adsorption removal, filtration, and / or decantation for removing unwanted substances other than the compound (P2) may be performed as needed.

[0095] Formula (P2): (R) 1 ) op (B) 2 ) [In the formula,] B 2 and R 1 The meaning is the same as above. op is (B) 2 (value) / (R) 1 The valence (of the valence) is a number that is either 1 or 2. Process B The manufacturing method of one embodiment of the present invention may further include step B, which removes the compound of formula (P2) generated as a byproduct in step A above.

[0096] Formula (P2): (R) 1 ) op (B) 2 ) [In the formula,] B 2 and R 1 The meaning is the same as above. op is (B) 2 (value) / (R)1 The valence (of the valence) is a number that is either 1 or 2. The removal of compound (P2) in step B is preferably carried out by, for example, distillation (which can be carried out under reduced pressure), filtration or decantation, or a combination thereof.

[0097] This distillation removal is preferably carried out under reduced pressure.

[0098] The conditions for this distillation removal can be appropriately set by those skilled in the art based on common technical knowledge in the field of chemistry.

[0099] For example, after step B, or during it, in order to reduce, for example, moisture (e.g., moisture from the atmosphere), recrystallization or azeotropic dehydration with the addition of any solvent, or a combination thereof, may be performed as needed.

[0100] The compound (P1) obtained in step A can be dried at any stage and any number of times by conventionally conceivable drying processes after step A and before it is used for purposes such as additives for electrochemical devices described later.

[0101] Additives for electrochemical devices An electrochemical device additive according to one embodiment of the present invention contains a compound represented by formula (P1A) and water in an amount of 0 to 50,000 ppm by mass relative to the compound represented by formula (P1).

[0102] Formula (P1A): RfCOOA d [In the formula,] Rf is an organic group having one or more fluorine atoms. A d These are metal atoms. In formula (P1A), from the viewpoint that fluorinated carboxylate compounds with low moisture content are readily obtained, and preferably fluorinated carboxylate compounds that are substantially free of moisture, Rf is preferably a hydrocarbon group having one or more fluorine atoms, more preferably an alkyl group having one or more fluorine atoms, even more preferably a C1-6 alkyl group having one or more fluorine atoms, and even more preferably a C1-3 alkyl group having two or more fluorine atoms.

[0103] Furthermore, in formula (P1A), from the viewpoint that fluorinated carboxylate compounds with low moisture content are readily obtained, and preferably fluorinated carboxylate compounds that are substantially free of moisture, A d Alkali metal atoms are preferred, Li, Na or K are more preferred, and Li is even more preferred.

[0104] From the viewpoint of the performance of electrochemical devices, the amount of water is preferably 20,000 ppm by mass or less, more preferably 10,000 ppm by mass or less, even more preferably 7,000 ppm by mass or less, and even more preferably 5,000 ppm by mass or less. The water content can also be 0 ppm by mass.

[0105] In this invention, the additive for electrochemical devices may be anhydrous, and if it is anhydrous, the lower limit of its amount is, for example, 50 ppm by mass, 100 ppm by mass, or 500 ppm by mass.

[0106] This additive for electrochemical devices can be used, for example, in the treatment of electrodes for electrochemical devices or lithium-ion secondary batteries.

[0107] The additive for this electrochemical device is included in such an electrochemical device or lithium-ion secondary battery due to its use. At this time, the additive for this electrochemical device can be modified or altered.

[0108] The present invention also discloses an electrochemical device containing the additive (or its variants or modifiers) of the present invention for electrochemical devices.

[0109] Such electrochemical devices can be understood based on common sense about technology.

[0110] compound One embodiment of the present invention is a compound of formula (P1A) with a moisture content of less than 50,000 ppm by mass.

[0111] Formula (P1A): RfCOOA d [In the formula,] Rf is an organic group having one or more fluorine atoms. A d [These are Li atoms.] In formula (P1A), from the viewpoint that fluorinated carboxylate compounds with low moisture content are readily obtained, and preferably fluorinated carboxylate compounds that are substantially free of moisture, Rf is preferably a hydrocarbon group having one or more fluorine atoms, more preferably an alkyl group having one or more fluorine atoms, even more preferably a C1-6 alkyl group having one or more fluorine atoms, and even more preferably a C1-3 alkyl group having two or more fluorine atoms.

[0112] Moisture content can be determined using the Karl Fischer method.

[0113] From the viewpoint of electrochemical device performance, the moisture content is preferably below 20,000 ppm by mass, more preferably below 10,000 ppm by mass, even more preferably below 7,000 ppm by mass, even more preferably below 5,000 ppm by mass, and particularly preferably below 3,000 ppm by mass. The moisture content can also be 0 ppm by mass. 0 ppm by mass means below the detection limit using the Karl Fischer method.

[0114] Here, the compound of one embodiment of the present invention may be water-free, and if it contains water, the lower limit of its amount is, for example, 50 ppm by mass, 100 ppm by mass, or 500 ppm by mass.

[0115] Those skilled in the art can understand this compound by referring to the description of additives for electrochemical devices in this invention.

[0116] Composition One embodiment of the present invention is a composition comprising a compound of formula (P1A) and water in an amount of 50,000 ppm by mass relative to the compound of formula (P1).

[0117] Formula (P1A): RfCOOA d [In the formula,] Rf is an organic group having one or more fluorine atoms. A d [These are Li atoms.] In formula (P1A), from the viewpoint that fluorinated carboxylate compounds with low moisture content are readily obtained, and preferably fluorinated carboxylate compounds that are substantially free of moisture, Rf is preferably a hydrocarbon group having one or more fluorine atoms, more preferably an alkyl group having one or more fluorine atoms, even more preferably a C1-6 alkyl group having one or more fluorine atoms, and even more preferably a C1-3 alkyl group having two or more fluorine atoms.

[0118] From the viewpoint of the performance of electrochemical devices, the water content is preferably below 20,000 ppm by mass, more preferably below 10,000 ppm by mass, even more preferably below 7,000 ppm by mass, even more preferably below 5,000 ppm by mass, and particularly preferably below 3,000 ppm by mass.

[0119] Here, the lower limit of the water content in the composition of one embodiment of the present invention can be, for example, 50 ppm by mass, 100 ppm by mass, or 500 ppm by mass.

[0120] Those skilled in the art can understand this composition by referring to the description of additives for electrochemical devices of the present invention.

[0121] electrolyte The electrolyte of one embodiment of the present invention contains the additives, compounds or compositions of the present invention for electrochemical devices.

[0122] From the viewpoint of the performance of the electrochemical device, the amount of the electrolyte relative to the whole is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, further preferably 0.1% by mass or more, further more preferably 0.2% by mass or more, and particularly preferably 0.5% by mass or more.

[0123] Furthermore, from the viewpoint of the performance of the electrochemical device, the amount of the electrolyte is typically 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, even more preferably 1.8% by mass or less, and particularly preferably 1.5% by mass or less, relative to the total electrolyte.

[0124] The electrolyte of the present invention preferably contains a solvent.

[0125] From the viewpoint of the performance of electrochemical devices, the solvents mentioned above preferably contain at least one selected from carbonates and carboxylic esters.

[0126] The aforementioned carbonates can be cyclic carbonates or chain carbonates.

[0127] The aforementioned cyclic carbonates can be non-fluorinated cyclic carbonates or fluorinated cyclic carbonates.

[0128] As examples of the aforementioned non-fluorinated cyclic carbonates, non-fluorinated saturated cyclic carbonates can be listed. From the viewpoint of the performance of electrochemical devices, non-fluorinated saturated alkylene carbonates having 2 to 6 carbon atoms are preferred, and non-fluorinated saturated alkylene carbonates having 2 to 4 carbon atoms are more preferred.

[0129] Among them, the non-fluorinated saturated cyclic carbonate is preferably selected from at least one of ethylene carbonate, propylene carbonate, cis-2,3-pentene carbonate, cis-2,3-butene carbonate, 2,3-pentene carbonate, 2,3-butene carbonate, 1,2-pentene carbonate, 1,2-butene carbonate and butene carbonate, considering its high dielectric constant and ease of achieving a suitable viscosity.

[0130] The above-mentioned non-fluorinated saturated cyclic carbonates can be used alone, or two or more can be used in any combination and proportion.

[0131] In the case of containing the above-mentioned non-fluorinated saturated cyclic carbonate, from the viewpoint of the performance of electrochemical devices, the content of the above-mentioned non-fluorinated saturated cyclic carbonate relative to the above-mentioned solvent is preferably 5 to 90 vol%, more preferably 10 to 60 vol%, and even more preferably 15 to 45 vol%.

[0132] The aforementioned fluorinated cyclic carbonates are cyclic carbonates containing fluorine atoms. Solvents containing fluorinated cyclic carbonates are also suitable for use under high voltage.

[0133] 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.

[0134] The aforementioned fluorinated cyclic carbonates can be either fluorinated saturated cyclic carbonates or fluorinated unsaturated cyclic carbonates.

[0135] The aforementioned fluorinated saturated cyclic carbonates are saturated cyclic carbonates containing fluorine atoms, specifically those represented by the following general formula (A). [In the formula, 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 (-O-). Examples of fluoroalkyl groups include -CF3, -CF2H, and -CH2F.

[0136] When the electrolyte contains the above-mentioned fluorinated saturated cyclic carbonate, its oxidation resistance is improved when the electrolyte is applied to high-voltage lithium-ion secondary batteries, etc., and stable and excellent charge-discharge characteristics are easily obtained.

[0137] From the perspective of dielectric constant and good oxidation resistance, X is preferred. 1 ~X 4 One or two of them are -F, can be fluoroalkyl with ether bonds, or can be fluoroalkoxy with ether bonds.

[0138] From the perspective of expecting to reduce low-temperature viscosity, increase flash point, and improve the solubility of electrolyte salts, X 1 ~X 4 Preferred are -H, -F, fluoroalkyl (a), fluoroalkyl with ether bond (b), or fluoroalkoxy (c).

[0139] The aforementioned fluoroalkyl group (a) is a group in which at least one hydrogen atom of the alkyl group is replaced by 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.

[0140] Among the fluoroalkyl groups (a) mentioned above, those with one carbon atom include CFH2-, CF2H-, and CF3-. In particular, considering the high-temperature storage properties, CF2H- or CF3- are preferred, with CF3- being the most preferred.

[0141] In the above-mentioned fluoroalkyl group (a), from the viewpoint of good solubility in electrolyte salts, the fluoroalkyl group shown in the following general formula (a-1) is preferred as a group having 2 or more carbon atoms.

[0142] R 1 -R 2 - (a-1) (where R) 1 It can be an alkyl group having 1 or more carbon atoms and containing fluorine atoms; R 2 It is an alkylene group having 1 to 3 carbon atoms and may have fluorine atoms; wherein, R 1 and R 2 (At least one of them has a fluorine atom.) Among them, R 1 and R 2 It can also have atoms other than carbon, hydrogen, and fluorine atoms.

[0143] 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.

[0144] As R 1 Specifically, examples include CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, which are straight-chain or branched alkyl groups. wait.

[0145] Additionally, in R 1When the alkyl group is a straight-chain alkyl group containing fluorine atoms, the following can be listed: CF3-, CF3CH2-, CF3CF2-, CF3CH2CH2-, CF3CF2CF2-, CF3CH2CF2-, CF3CH2CH2CH2-, CF3CH2CF2CH2-, CF3CF2CF2CH2-, CF3CF2CF2CH2-, CF3CF2CF2CF2-, CF3CF2CH2CH2CH2-, CF3CF2CH2CH2CH2 2-, 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.

[0146] Additionally, in R 1 In the case of a branched alkyl group having a fluorine atom, the following are preferred examples: wait.

[0147] However, when there are side chains such as CH3- or CF3-, the viscosity tends to increase, so it is preferable to have fewer (1) or zero of them.

[0148] R 2 It can be an alkylene group having 1 to 3 carbon atoms and containing fluorine atoms. R 2 It can be either linear or branched. Below is an example of the smallest structural unit constituting such a linear or branched alkylene group. R 2 It consists of them individually or in combination.

[0149] (i) The smallest linear structural unit: -CH2-, -CHF-, -CF2-, -CHCl-, -CFCl-, -CCl2-.

[0150] (ii) Branched minimum structural unit: In the examples above, from the viewpoint of not triggering the deHCl reaction due to alkali and being more stable, it is preferable to be composed of structural units that do not contain Cl.

[0151] In R 2 In the case of a linear structure, it is composed only of the aforementioned linear minimum structural units, wherein -CH2-, -CH2CH2-, or -CF2- are preferred. From the viewpoint of further improving the solubility of the electrolyte salt, -CH2- or -CH2CH2- are more preferred.

[0152] In R 2 In the case of a branched structure, it contains at least one of the aforementioned branched minimum structural units, preferably exemplified by the general formula – (CX a X b ) - (X a For H, F, CH3 or CF3; X b It is CH3 or CF3. Wherein, in X b When it is CF3, X a These are groups represented by H or CH3. They can further enhance the solubility of electrolyte salts.

[0153] Preferred fluoroalkyl groups (a) include, for example, CF3CF2-, HCF2CF2-, H2CFCF2-, CH3CF2-, CF3CHF-, CH3CF2-, CF3CF2CF2-, HCF2CF2CF2-, H2CFCF2CF2-, CH3CF2CF2-. wait.

[0154] The aforementioned fluoroalkyl group (b) having an ether bond is a group having an ether bond in which at least one hydrogen atom of the alkyl group is replaced by a fluorine atom. The number of carbon atoms in the aforementioned fluoroalkyl group (b) having an ether bond is preferably 2 to 17. When the number of carbon atoms is too high, the viscosity of the aforementioned fluorinated saturated cyclic carbonate increases, and due to the increase in fluorine-containing groups, the solubility of the electrolyte salt and the compatibility with other solvents may decrease due to a decrease in the dielectric constant. From this viewpoint, the number of carbon atoms in the aforementioned fluoroalkyl group (b) having an ether bond is more preferably 2 to 10, and even more preferably 2 to 7.

[0155] The alkylene group constituting the ether moiety of the aforementioned fluoroalkyl group (b) with an ether bond can be a straight-chain or branched alkylene group. An example of the smallest structural unit constituting such a straight-chain or branched alkylene group is shown below.

[0156] (i) The smallest linear structural unit: -CH2-, -CHF-, -CF2-, -CHCl-, -CFCl-, -CCl2-.

[0157] (ii) Branched minimum structural unit: Alkylenes can be composed of these smallest structural units individually, or they can be composed of straight-chain (i) units, branched-chain (ii) units, or a combination of straight-chain (i) and branched-chain (ii) units. Preferred examples are described later.

[0158] In the examples above, from the viewpoint of not triggering the deHCl reaction due to alkali and being more stable, it is preferable to be composed of structural units that do not contain Cl.

[0159] As a further preferred fluoroalkyl group having an ether bond (b), groups represented by general formula (b-1) can be listed.

[0160] R 3 - (OR) 4 ) n1 - (b-1) (where R) 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.) As R 3 and R 4 Examples of such groups can be found, which can be appropriately combined to form a fluoroalkyl group (b) with an ether bond as shown in the above general formula (b-1), but are not limited to these.

[0161] (1) As R 3 Preferred general formula: 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).

[0162] When n2 is 0, as R 3 Examples include CH3-, CF3-, HCF2- and H2CF-.

[0163] 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-, CF3C F2CF2CF2CH2CH2-, CF3CF2CH2CF2CH2CH2-, HCF2CH2-, HCF2CF2-, HCF2CH2CH2-, HCF2CF2CH2-, HCF2CH2CF2-, HCF2C F2CH2CH2-, HCF2CH2CF2CH2-, HCF2CF2CF2CF2-, HCF2CF2CH2CH2CH2-, HCF2CH2CF2CH2CH2-, HCF2CF2CF2CF2CH2-, HCF2CF2CF2CF2CH2CH2-, FCH2CH2-, FCH2CF2-, FCH2CF2CH2-, CH3CF2-, CH3CH2-, CH3CF2CH2-, CH3CF2CF2-, CH3CH2 CH2-, CH3CF2CH2CF2-, CH3CF2CF2CF2-, CH3CH2CF2CF2-, CH3CH2CH2CH2-, CH3CF2CH2CF2CH2-, CH3CF2CF2CF2CH2-, CH3CF2CF2CH2CH2-, CH3CH2CF2CF2CH2-, CH3CF2CH2CF2CH2CH2-, CH3CH2CF2CF2CH2CH2-, CH3CF2CH2CF2CH2CH2-, etc.

[0164] As n2 is 1 and R 3 Branched groups can be listed as follows: wait.

[0165] However, when there are side chains such as CH3− or CF3−, the viscosity tends to increase, therefore R 3 Further preferred are straight-chain groups.

[0166] (2) In the above general formula (b-1), -(OR) 4 ) n1In the given information, n1 is an integer from 1 to 3, preferably 1 or 2. Specifically, when n1 = 2 or 3, R... 4 They can be the same or different.

[0167] As R 4 Preferred specific examples may include the following straight-chain or branched groups.

[0168] Examples of linear groups include -CH2-, -CHF-, -CF2-, -CH2CH2-, -CF2CH2-, -CF2CF2-, -CH2CF2-, -CH2CH2CH2-, -CH2CH2CF2-, -CH2CF2CH2-, -CH2CF2CF2-, -CF2CH2CH2-, -CF2CF2CH2-, -CF2CH2CF2-, -CF2CF2CF2-, and -CF2CF2CF2-.

[0169] Examples of branched groups include: wait.

[0170] The aforementioned fluoroalkoxy group (c) is a group in which at least one hydrogen atom of the alkoxy group is substituted by 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.

[0171] As for the above-mentioned fluoroalkoxy group (c), the general formula X is particularly preferred. 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 there are 3 X atoms d The fluoroalkoxy group (containing any number of fluorine atoms) is shown as a fluoroalkoxy group.

[0172] As a specific example of the above-mentioned fluoroalkoxy group (c), the R group in the above general formula (a-1) can be listed. 1 The alkyl group shown is terminally bonded with a fluoroalkoxy group containing an oxygen atom.

[0173] From the perspective of reducing viscosity at low temperatures and increasing flash point, the fluorine content of the fluoroalkyl group (a), the fluoroalkyl group with ether bond (b), and the fluoroalkoxy group (c) in the above-mentioned fluorosaturated cyclic carbonate is preferably 10% by mass or more, more preferably 12% by mass or more, and even more preferably 15% by mass or more. The upper limit is usually 76% by mass.

[0174] The fluorine content of fluoroalkyl (a), fluoroalkyl with ether bonds (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 (mass%).

[0175] Furthermore, from the viewpoint of good dielectric constant and 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.

[0176] The fluorine content of the above-mentioned fluorinated saturated cyclic carbonate is calculated based on the structural formula of the fluorinated saturated cyclic carbonate by using {(number of fluorine atoms × 19) / molecular weight of fluorinated saturated cyclic carbonate} × 100 (mass%).

[0177] Specifically, examples of the aforementioned fluorinated saturated cyclic carbonates are listed below.

[0178] As X 1 ~X 4 Specific examples of fluorosaturated cyclic carbonates in which at least one is -F can be listed as follows: wait.

[0179] These compounds have high voltage resistance and good solubility in electrolyte salts.

[0180] Alternatively, you can use: wait.

[0181] As X 1 ~X 4 Specific examples of fluorosaturated cyclic carbonates in which at least one alkyl group (a) is fluoro and the remainder is all -H can be listed as follows: wait.

[0182] 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 are all -H, can be listed as follows: wait.

[0183] Among them, any of the following compounds are preferred as the above-mentioned fluorinated saturated cyclic carbonates. In addition to the aforementioned fluorinated saturated cyclic carbonates, other examples include trans-4,5-difluoro-1,3-dioxolane-2-one, 5-(1,1-difluoroethyl)-4,4-difluoro-1,3-dioxolane-2-one, 4-methylene-1,3-dioxolane-2-one, 4-methyl-5-trifluoromethyl-1,3-dioxolane-2-one, 4-ethyl-5-fluoro-1,3-dioxolane-2-one, and 4-ethyl-5,5-difluoro -1,3-dioxolane-2-one, 4-ethyl-4,5-difluoro-1,3-dioxolane-2-one, 4-ethyl-4,5,5-trifluoro-1,3-dioxolane-2-one, 4,4-difluoro-5-methyl-1,3-dioxolane-2-one, 4-fluoro-5-methyl-1,3-dioxolane-2-one, 4-fluoro-5-trifluoromethyl-1,3-dioxolane-2-one, 4,4-difluoro-1,3-dioxolane-2-one, etc.

[0184] Of the aforementioned fluorinated saturated cyclic carbonates, from the viewpoint of the performance of electrochemical devices, fluoroethylene carbonate, difluoroethylene carbonate, trifluoromethyl ethylene carbonate (3,3,3-trifluoropropylene carbonate), and 2,2,3,3,3-pentafluoropropyl ethylene carbonate are more preferred.

[0185] The aforementioned fluorinated unsaturated cyclic carbonates are cyclic carbonates having unsaturated bonds and fluorine atoms. From the viewpoint of electrochemical device performance, fluoroethylene carbonate derivatives substituted with substituents having aromatic rings or carbon-carbon double bonds are preferred. Specifically, examples include 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-vinylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, and 4,5-difluoro-4,5-diallylethylene carbonate.

[0186] The above-mentioned fluorocyclic carbonates can be used alone or in combination or proportion of two or more.

[0187] In the case of containing the above-mentioned fluorinated cyclic carbonate, from the viewpoint of the performance of electrochemical devices, the content of the above-mentioned fluorinated cyclic carbonate relative to the above-mentioned solvent is preferably 5 to 90 vol%, more preferably 10 to 60 vol%, and even more preferably 15 to 45 vol%.

[0188] The aforementioned chain carbonates can be either non-fluorinated chain carbonates or fluorinated chain carbonates.

[0189] Examples of non-fluorinated chain carbonates include, for instance, 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-pentylene carbonate, trans-2,3-butylene carbonate, and ethyl phenyl carbonate. From the viewpoint of electrochemical device performance, at least one of ethyl methyl carbonate, diethyl carbonate, and dimethyl carbonate is preferred.

[0190] The above-mentioned non-fluorinated chain carbonates can be used alone or in combination or proportion of two or more.

[0191] In the case of containing the above-mentioned non-fluorinated chain carbonate, from the viewpoint of the performance of electrochemical devices, the content of the above-mentioned non-fluorinated chain carbonate 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%.

[0192] The aforementioned fluorinated chain carbonates are chain carbonates containing fluorine atoms. Solvents containing fluorinated chain carbonates are also suitable for use under high voltage.

[0193] As examples of the aforementioned fluorinated chain carbonates, compounds represented by general formula (B) can be listed.

[0194] Rf 2 OCOOR 7 (B) (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. 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.

[0195] The aforementioned fluoroalkyl group is a group in which at least one of the hydrogen atoms of an alkyl group is replaced by a fluorine atom. In R 7 When it is an alkyl group containing a fluorine atom, it is a fluoroalkyl group.

[0196] From the perspectives of low viscosity and the solubility of electrolyte salts, Rf 2 and R 7 The number of carbon atoms is preferably 1 to 7, and more preferably 1 to 2.

[0197] Examples of fluoroalkyl groups with one carbon atom include CFH2−, CF2H−, and CF3−. Considering high-temperature storage properties, CFH2− or CF3− are particularly preferred.

[0198] From the viewpoint of good solubility in electrolyte salts, fluoroalkyl groups with two or more carbon atoms are preferably exemplified by the following general formula (d-1).

[0199] R 1 -R 2 - (d-1) (where R) 1 It can be an alkyl group having 1 or more carbon atoms and containing fluorine atoms; R 2 It is an alkylene group having 1 to 3 carbon atoms and may have fluorine atoms; wherein, R 1 and R 2 (At least one of them has a fluorine atom.) Furthermore, R 1 and R 2 It can also have other atoms besides carbon, hydrogen, and fluorine atoms.

[0200] 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.

[0201] As R 1 Specifically, examples of linear or branched alkyl groups include: CH3-, CF3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, wait.

[0202] Additionally, in R 1When the alkyl group is a straight-chain alkyl group having fluorine atoms, the following can be listed: CF3-, CF3CH2-, CF3CF2-, CF3CH2CH2-, CF3CF2CH2-, CF3CH2CF2-, CF3CH2CH2CH2-, CF3CH2CF2CH2-, CF3CF2CF2CH2-, CF3CF2CF2CF2-, CF3CF2CH2CF2-, CF3CH2CH2CH2CH2-, 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.

[0203] Additionally, in R 1 In the case of a branched alkyl group having fluorine atoms, the following are preferred examples: wait.

[0204] However, when there are side chains such as CH3- or CF3-, the viscosity tends to increase, so it is preferable to have fewer (1) or zero of them.

[0205] R 2 It can be an alkylene group with 1 to 3 carbon atoms and containing fluorine atoms. R 2 It can be either linear or branched. Below is an example of the smallest structural unit constituting such a linear or branched alkylene group. R 2 It consists of them individually or in combination.

[0206] (i) The smallest linear structural unit: -CH2-, -CHF-, -CF2-, -CHCl-, -CFCl-, -CCl2-.

[0207] (ii) Branched minimum structural unit: In the examples above, from the viewpoint of not triggering the deHCl reaction due to alkali and being more stable, it is preferable to be composed of structural units that do not contain Cl.

[0208] In R 2 In the case of a linear structure, it is composed only of the aforementioned linear minimum structural units, wherein -CH2-, -CH2CH2-, or -CF2- are preferred. From the viewpoint of further improving the solubility of the electrolyte salt, -CH2- or -CH2CH2- are more preferred.

[0209] In R 2 In the case of a branched structure, it contains at least one of the aforementioned branched minimum structural units, preferably exemplified by the general formula – (CX a X b ) - (X a For H, F, CH3 or CF3; X b It is CH3 or CF3. Wherein, in X b When it is CF3, X a These are groups represented by H or CH3. They can further enhance the solubility of electrolyte salts.

[0210] Preferred fluoroalkyl groups include, specifically, CF3CF2-, HCF2CF2-, H2CFCF2-, CH3CF2-, CF3CH2-, CF3CF2CF2-, HCF2CF2CF2-, H2CFCF2CF2-, CH3CF2CF2-, wait.

[0211] Among them, as Rf 2 and R 7Fluoroalkyl groups are preferred, such as CF3-, CF3CF2-, (CF3)2CH-, CF3CH2-, C2F5CH2-, CF3CF2CH2-, HCF2CF2CH2-, CF3CFHCF2CH2-, CFH2-, and CF2H-. From the viewpoint of high flame retardancy, good rate capability and good oxidation resistance, CF3CH2-, CF3CF2CH2-, HCF2CF2CH2-, CFH2-, and CF2H- are more preferred.

[0212] In R 7 When it is an alkyl group that does not contain fluorine atoms, it is an alkyl group with 1 to 7 carbon atoms. From the viewpoint of low viscosity, R 7 The number of carbon atoms is preferably 1 to 4, more preferably 1 to 3.

[0213] 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 viewpoint of low viscosity and good rate capability.

[0214] The fluorine content of the aforementioned fluorinated chain carbonate is preferably 15 to 70% by mass. When the fluorine content is within the above range, it can maintain compatibility with solvents and solubility in salts. The aforementioned fluorine content is more preferably 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 further preferably 50% by mass or less.

[0215] The fluorine content in this invention is calculated based on the structural formula of the above-mentioned fluorinated chain carbonate by using {(number of fluorine atoms × 19) / molecular weight of fluorinated chain carbonate} × 100 (mass%).

[0216] From the viewpoint of low viscosity, any of the following compounds are preferred as the above-mentioned fluorinated chain carbonates. As the above-mentioned fluorinated chain carbonate, methyl 2,2,2-trifluoroethyl carbonate (F3CH2COC(=O)OCH3) is particularly preferred.

[0217] The above-mentioned fluorinated chain carbonates can be used alone or in combination or proportion of two or more.

[0218] In the case of containing the above-mentioned fluorinated chain carbonate, from the viewpoint of the performance of electrochemical devices, the content of the above-mentioned fluorinated chain carbonate 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%.

[0219] The aforementioned carboxylic esters can be cyclic carboxylic esters or chain carboxylic esters.

[0220] The aforementioned cyclic carboxylic acid esters can be either non-fluorinated cyclic carboxylic acid esters or fluorinated cyclic carboxylic acid esters.

[0221] As examples of the aforementioned non-fluorinated cyclic carboxylic acid esters, non-fluorinated saturated cyclic carboxylic acid esters can be listed. From the viewpoint of the performance of electrochemical devices, non-fluorinated saturated cyclic carboxylic acid esters having 2 to 4 carbon atoms are preferred.

[0222] Specific examples of non-fluorinated 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 viewpoint of improving lithium-ion dissociation and loading characteristics.

[0223] The above-mentioned non-fluorinated saturated cyclic carboxylic esters can be used alone, or two or more can be used in any combination and proportion.

[0224] In the case of containing the above-mentioned non-fluorinated saturated cyclic carboxylic acid ester, from the viewpoint of the performance of the electrochemical device, the content of the above-mentioned non-fluorinated 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.

[0225] The aforementioned chain carboxylic esters can be non-fluorinated or fluorinated. When the solvent contains the aforementioned chain carboxylic esters, the increase in resistance of the electrolyte after high-temperature storage can be further suppressed.

[0226] Examples of the aforementioned non-fluorinated 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 neopentanoate, n-propyl formate, n-propyl acetate, n-butyl formate. Neopentanoic acid n-butyl ester, neopentanoic acid n-octyl ester, ethyl-2-(dimethoxyphosphoryl)acetate, ethyl-2-(dimethylphosphoryl)acetate, ethyl-2-(diethoxyphosphoryl)acetate, ethyl-2-(diethylphosphoryl)acetate, isopropyl propionate, isopropyl acetate, ethyl formate, ethyl-2-propynyl oxalate, isopropyl formate, isopropyl butyrate, isobutyl formate, isobutyl propionate, isobutyl butyrate, isobutyl acetate, etc.

[0227] From the perspective of the performance of electrochemical devices, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate are preferred, with ethyl propionate and propyl propionate being particularly preferred.

[0228] The above-mentioned non-fluorinated chain carboxylic esters can be used alone, or two or more can be used in any combination and proportion.

[0229] In the case of containing the above-mentioned non-fluorinated chain carboxylic ester, from the viewpoint of the performance of the electrochemical device, the content of the above-mentioned non-fluorinated chain carboxylic ester relative to the above-mentioned solvent is preferably 0 to 90 vol%, more preferably 0.001 to 90 vol%, further preferably 1 to 60 vol%, and particularly preferably 5 to 40 vol%.

[0230] The aforementioned fluorinated chain carboxylic esters are chain carboxylic esters containing fluorine atoms. Solvents containing fluorinated chain carboxylic esters are also suitable for use under high voltage.

[0231] From the viewpoint of good compatibility with other solvents and good oxidation resistance, the following general formula is preferred as the above-mentioned fluorinated chain carboxylic ester: R 31 COOR 32 (where R) 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 A fluorinated chain carboxylic acid ester (at least one of which contains a fluorine atom) is shown.

[0232] As R 31 and R 32, for example, non-fluorinated alkyl groups such as methyl (-CH3), ethyl (-CH2CH3), propyl (-CH2CH2CH3), isopropyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3), tert-butyl (-C(CH3)3); -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, -CH2CH2CH2CF2H, -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)CF2HFluoroalkyl 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 from the viewpoint of good compatibility with other solvents, viscosity, and oxidation resistance.

[0233] Specific examples of the aforementioned fluorinated chain carboxylic acid esters include CF3CH2C(=O)OCH3 (methyl 3,3,3-trifluoropropionate), HCF2C(=O)OCH3 (methyl difluoroacetate), HCF2C(=O)OC2H5 (ethyl difluoroacetate), CF3C(=O)OCH2CH2CF3, CF3C(=O)OCH2C2F5, 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, ethyl trifluoroacetate, and so on. One or more of the following: tert-butyl fluoroacetate, 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), 1H,1H-heptafluorobutyl acetate, 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, methyl 2-(trifluoromethyl)-3,3,3-trifluoropropionate, and methyl heptafluorobutyrate.

[0234] From the perspectives of electrochemical device performance, 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, methyl 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, and CH3C(=O)OCH2C. F3, 1H,1H-heptafluorobutyl acetate, 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)butyrate, methyl ... Methyl heptafluoropropionate (HFC)-3,3,3-trifluoropropionate and methyl heptafluorobutyrate, more preferably CF3CH2C(=O)OCH3, HCF2C(=O)OCH3, HCF2C(=O)OC2H5, CH3C(=O)OCH2CF3, and particularly preferably HCF2C(=O)OCH3, HCF2C(=O)OC2H5, CH3C(=O)OCH2CF3.

[0235] The above-mentioned fluorinated chain carboxylic esters can be used alone, or two or more can be used in any combination and proportion.

[0236] In the case of containing the above-mentioned fluorinated chain carboxylic ester, from the viewpoint of the performance of the electrochemical device, the content of the above-mentioned fluorinated chain carboxylic ester is preferably 10 to 90 vol% relative to the above-mentioned solvent, more preferably 40 to 85 vol%, and even more preferably 50 to 80 vol%.

[0237] From the viewpoint of electrochemical device performance, the solvent preferably contains at least one selected from the above-mentioned cyclic carbonate, the above-mentioned linear carbonate, and the above-mentioned linear carboxylic acid ester; more preferably, it contains the above-mentioned cyclic carbonate and at least one selected from the above-mentioned linear carbonate and the above-mentioned linear carboxylic acid ester. The above-mentioned cyclic carbonate is preferably a saturated cyclic carbonate.

[0238] Electrolytes containing the above-mentioned solvents can further enhance the high-temperature storage and cycling characteristics of electrochemical devices.

[0239] When the solvent contains the cyclic carbonate and at least one of the cyclic carbonate and the cyclic carboxylic acid ester, from the viewpoint of the performance of the electrochemical device, the cyclic carbonate and at least one of the cyclic carbonate and the cyclic carboxylic acid ester are preferably contained in an aggregate of 10 to 100 vol%, more preferably 30 to 100 vol%, and even more preferably 50 to 100 vol%.

[0240] When the solvent contains the cyclic carbonate and at least one of the linear carbonate and the linear carboxylic acid ester, from the viewpoint of the performance of the electrochemical device, the volume ratio of the cyclic carbonate to at least one of the linear carbonate and the linear 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.

[0241] The solvent described above preferably contains at least one selected from the above-mentioned non-fluorinated saturated cyclic carbonates, the above-mentioned non-fluorinated chain carbonates, and the above-mentioned non-fluorinated chain carboxylic acid esters. From the viewpoint of the performance of electrochemical devices, it is more preferable that the solvent contains the above-mentioned non-fluorinated saturated cyclic carbonates and at least one selected from the above-mentioned non-fluorinated chain carbonates and the above-mentioned non-fluorinated chain carboxylic acid esters. Electrolytes containing the solvents described above are suitable for electrochemical devices used at lower voltages.

[0242] When the solvent contains the non-fluorinated saturated cyclic carbonate and at least one of the non-fluorinated chain carbonate and the non-fluorinated chain carboxylic acid ester, from the viewpoint of the performance of the electrochemical device, the total amount of the non-fluorinated saturated cyclic carbonate and at least one of the non-fluorinated chain carbonate and the non-fluorinated chain carboxylic acid ester is preferably 5 to 100 vol%, more preferably 20 to 100 vol%, and even more preferably 30 to 100 vol%.

[0243] When the electrolyte contains the aforementioned non-fluorinated saturated cyclic carbonate and at least one selected from the aforementioned non-fluorinated chain carbonate and the aforementioned non-fluorinated chain carboxylic acid ester, from the viewpoint of the performance of the electrochemical device, the volume ratio of the aforementioned non-fluorinated saturated cyclic carbonate to at least one selected from the aforementioned non-fluorinated chain carbonate and the aforementioned non-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.

[0244] From the viewpoint of electrochemical device performance, 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 electrochemical devices used at lower voltages but also for electrochemical devices used at higher voltages.

[0245] 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, from the viewpoint of the performance of the electrochemical device, the fluorinated saturated cyclic carbonate and at least one selected from the fluorinated chain carbonate and the fluorinated chain carboxylic acid ester are preferably contained in an aggregate of 5 to 100 vol%, more preferably 10 to 100 vol%, and even more preferably 30 to 100 vol%.

[0246] When the solvent contains the aforementioned fluorinated saturated cyclic carbonate and at least one selected from the aforementioned fluorinated chain carbonate and the aforementioned fluorinated chain carboxylic acid ester, from the viewpoint of the performance of the electrochemical device, the volume ratio of the aforementioned fluorinated saturated cyclic carbonate to at least one selected from the aforementioned fluorinated chain carbonate and the aforementioned 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.

[0247] In addition, ionic liquids can also be used as the solvents mentioned above. An "ionic liquid" is a liquid composed of ions formed by the combination of organic cations and anions.

[0248] As organic cations, there are no particular limitations, but examples include: imidazolium ions such as dialkylimidazolium cations and trialkylimidazolium cations; tetraalkylammonium ions; alkylpyridinium ions; dialkylpyrrolidineium ions; and dialkylpiperidineium ions.

[0249] There are no particular limitations on the anions that can be used to balance these organic cations. For example, PF6 anion, PF3(C2F5)3 anion, PF3(CF3)3 anion, BF4 anion, BF2(CF3)2 anion, BF3(CF3) anion, dioxaborate anion, P(C2O4)F2 anion, Tf (trifluoromethanesulfonyl) anion, Nf (nonafluorobutyryl) anion, bis(fluorosulfonyl)imide anion, bis(trifluoromethanesulfonyl)imide anion, bis(pentafluoroethanesulfonyl)imide anion, dicyanoamine anion, and halide anions can be used.

[0250] From the viewpoint of the performance of electrochemical devices, the solvents mentioned above are preferably non-aqueous solvents, and the electrolyte of the present invention is preferably a non-aqueous electrolyte.

[0251] From the viewpoint of the performance of electrochemical devices, the content of the solvent is preferably 70 to 99.999% by mass in the electrolyte, more preferably 80% by mass or more, and more preferably 92% by mass or less.

[0252] The electrolyte of the present invention may also contain a compound (5) represented by general formula (5).

[0253] General formula (5): (In the formula, A a＋ It indicates metal ions, hydrogen ions, or onium ions.

[0254] 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 This refers to transition metals and elements in groups III, IV, or V of the periodic table.

[0255] X 201 This indicates O, S, alkylene groups with 1 to 10 carbon atoms, alkyl halides with 1 to 10 carbon atoms, aryl groups with 6 to 20 carbon atoms, or aryl halides with 6 to 20 carbon atoms (alkylene groups, alkyl halides, aryl groups, and aryl halides may have substituents or heteroatoms in their structure; additionally, when n202 is 1 and n203 is 2 to 4, the X atoms in n203...). 201 (They can be combined).

[0256] L 201 The terms represent 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 (alkylene, haloalkylene, arylene, and haloarylene can have substituents and heteroatoms in their structures). Additionally, when n201 is 2 to 8, the L atoms in n201... 201 (They can combine to form a ring) or -Z 203 Y 203 .

[0257] Y 201 Y 202 and Z 203 Each is independent of the others: O, S, NY 204 Hydrocarbon group or fluorinated hydrocarbon group. Y 203 and Y 204Independently representing H, F, alkyl groups with 1-10 carbon atoms, haloalkyl groups with 1-10 carbon atoms, aryl groups with 6-20 carbon atoms, or haloaryl groups with 6-20 carbon atoms (alkyl, haloalkyl, aryl, and haloaryl groups may have substituents and heteroatoms in their structure), Y 203 Or Y 204 When multiple instances exist, they can combine with each other to form a ring.

[0258] As A a＋ Examples of ions that can be listed include 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, and triethylsulfonium ions.

[0259] When used in applications such as electrochemical devices, from the perspective of the performance of electrochemical devices, A a＋ Lithium ions, sodium ions, magnesium ions, tetraalkylammonium ions, and hydrogen ions are preferred, with lithium ions being particularly preferred. From the viewpoint of easily adjusting the lattice energy and thus readily dissolving in solvents, A... a＋ The valence a of the cation is an integer from 1 to 3. Where solubility is a concern, 1 is more preferred. The valence b of the anion is also an integer from 1 to 3, and is particularly preferred to be 1. The constant p representing the ratio of cation to anion is necessarily determined by the ratio of their valences, b / a.

[0260] The ligand portion of general formula (5) will now 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 bound together are called ligands.

[0261] From the perspective of the performance of electrochemical devices, 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.

[0262] 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, they may have halogen atoms, chain-like or cyclic alkyl groups, aryl groups, alkenyl groups, alkoxy groups, aryloxy groups, sulfonyl groups, amino groups, cyano groups, carbonyl groups, acyl groups, amide groups, or hydroxyl groups as substituents to replace hydrogen on the alkylene and arylene groups, or they may have structures with nitrogen, sulfur, or oxygen introduced to replace carbon on the alkylene and arylene groups. Furthermore, when n202 is 1 and n203 is 2 to 4, the X atoms in n203... 201 They can bind to each other. As an example, ligands such as ethylenediaminetetraacetic acid (EDTA) can be cited.

[0263] 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 (Regarding Z) 203 Y 203 (To be explained later). Here, alkyl and aryl groups also relate to X. 201 Similarly, its structure can contain substituents and heteroatoms. Furthermore, when n201 is 2–8, n201 L... 201 They can combine to form a ring. As L 201 Preferably, fluorine or cyano groups are used. With fluorine atoms, the solubility and dissociation of the anionic compound salt are increased, thus facilitating improved ionic conductivity. Furthermore, oxidation resistance is enhanced, making it easier to suppress side reactions.

[0264] Y 201 Y 202 and Z 203 O, S, and NY are represented independently respectively. 204 Hydrocarbon group or fluorinated hydrocarbon group. From the perspective of electrochemical device performance, Y 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 bond, therefore these ligands are related to Z. 201 This forms a chelate structure. Through this chelate effect, the compound's heat resistance, chemical stability, and hydrolysis resistance are easily improved. The constant n2O2 in this ligand is 0 or 1. In particular, when it is 0, the chelate ring becomes a five-membered ring, thus maximizing the chelate effect and easily improving stability.

[0265] 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.

[0266] Y 203 and Y 204 Each of the following can be 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. Additionally, Y... 203 Or Y 204 When multiple instances exist, they can combine to form a ring.

[0267] Furthermore, the constant n203 related to the number of ligands is an integer from 1 to 4. From the viewpoint of the performance of the electrochemical device, 1 or 2 is preferred, and 2 is more preferred. Additionally, the constant n201 related to the number of ligands is an integer from 0 to 8. From the viewpoint of the performance of the electrochemical device, an integer from 0 to 4 is preferred, and 0, 2, or 4 is more preferred. It is further preferred that n201 is 2 when n203 is 1, and n201 is 0 when n203 is 2.

[0268] In general formula (5), alkyl, haloalkyl, aryl, haloaryl also include groups with branched chains or other functional groups such as hydroxyl, ether bond, etc.

[0269] As compound (5), the preferred general formula is: (where A) a＋ a, b, p, n201, Z 201 and L 201 As mentioned above), or general formula: (where A) a＋ a, b, p, n201, Z 201 and L 201 The compound shown above.

[0270] As compounds (5), lithium oxalate-borate salts can be listed, including: The following formula: The lithium di(oxalate)borate (LIBOB) shown is... The following formula: .

[0271] Lithium difluorooxalate borate (LIDFOB) is shown.

[0272] As compounds (5), the following can also be listed: The following formula: The lithium difluorooxalate phosphate (LIDFOP) shown is... The following formula: The lithium tetrafluorooxalate phosphate (LITFOP) shown is shown. The following formula: Lithium di(oxalate) difluorophosphate, etc., are shown.

[0273] 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.

[0274] 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.

[0275] Specific examples of dicarboxylic acid complex salts with aluminum as the central element include LiAl(C2O4)2 and LiAlF2(C2O4).

[0276] From the perspective of easy availability and the ability to form stable film-like structures, lithium di(oxalate)borate, lithium difluoro(oxalate)borate, lithium tri(oxalate)phosphate, lithium difluorobis(oxalate)phosphate, and lithium tetrafluoro(oxalate)phosphate are more suitable.

[0277] Lithium di(oxalate)borate is particularly preferred as compound (5).

[0278] From the viewpoint of obtaining better cycling characteristics, the content of compound (5) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, relative to the solvent; preferably 10% by mass or less, more preferably 3% by mass or less.

[0279] From the viewpoint of the performance of electrochemical devices, the electrolyte of the present invention preferably also contains an electrolyte salt (but does not include compounds (1) and (5)). As the electrolyte salt, in addition to lithium salts, ammonium salts, and metal salts, any electrolyte salt that can be used in the electrolyte, such as liquid salts (ionic liquids), inorganic polymeric salts, and organic polymeric salts, can also be used.

[0280] Lithium salts are preferred as electrolyte salts for lithium-ion secondary batteries.

[0281] As the lithium salt mentioned above, any lithium salt can be used, and the following lithium salts can be listed as examples: LiPF6, LiBF4, LiClO4, LiAlF4, LiSbF6, LiTaF6, LiWF7, LiAsF6, LiAlCl4, LiI, LiBr, LiCl, LiB 10 Cl 10 Inorganic lithium salts such as Li2SiF6, Li2PFO3, and LiPO2F2; Lithium tungstates such as LiWOF5; Lithium carboxylate salts such as HCO2Li, CH3CO2Li, CH2FCO2Li, CHF2CO2Li, CF3CO2Li, CF3CH2CO2Li, CF3CF2CO2Li, CF3CF2CF2CO2Li, CF3CF2CF2CF2CO2Li, etc. 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. 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; Methyl lithium salts such as LiC(FSO2)3, LiC(CF3SO2)3, and LiC(C2F5SO2)3; And the formula: 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) The salts shown include (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 and other 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.

[0282] From the perspective of improving output characteristics, high-rate charge-discharge characteristics, high-temperature storage characteristics, and cycle characteristics, lithium salts of at least one of LiPF6, LiBF4, LiSbF6, LiTaF6, LiPO2F2, FSO3Li, CF3SO3Li, LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)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, and LiPF3(C2F5)3 are particularly preferred.

[0283] These electrolyte salts can be used alone or in combination of two or more. When two or more are used in combination, preferred examples include LiPF6 and LiBF4, or LiPF6 and LiPO2F2, C2H5OSO3Li, or FSO3Li, which have the effect of improving high-temperature storage characteristics, loading characteristics, and cycling characteristics.

[0284] In this case, the amount of LiBF4, LiPO2F2, C2H5OSO3Li or FSO3Li in combination relative to 100% by mass of the electrolyte is not limited, and is arbitrary as long as it does not significantly impair the effect of the present invention. Relative to the electrolyte of the present invention, it 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.

[0285] In addition, other examples include the combined use of inorganic and organic lithium salts, which have the effect of suppressing degradation caused by high-temperature storage. Preferred organic lithium salts include CF3SO3Li, LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)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, and LiPF3(C2F5)3. In this case, from the viewpoint of the performance of the electrochemical device, the proportion of 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 preferably 30% by mass or less, particularly preferably 20% by mass or less.

[0286] There are no particular limitations regarding the concentration of these electrolyte salts in the electrolyte, as long as it does not impair the effects of the present invention. From the viewpoint of ensuring good battery performance by keeping the conductivity of the electrolyte within a good range, 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, even more preferably 2.0 mol / L or less.

[0287] Ammonium salts are preferred as electrolyte salts for electrolytes used in double-layer capacitors.

[0288] The following (IIa) to (IIe) can be listed as ammonium salts mentioned above.

[0289] (IIa) Tetraalkyl quaternary ammonium salt The tetraalkyl quaternary ammonium salt of general formula (IIa) is preferred. (where R) 1a R 2a R 3a and R 4aWhether the two are the same or different, they are all alkyl groups with 1 to 6 carbon atoms that may contain ether bonds; X － (This indicates anion.) Furthermore, from the viewpoint of improving oxidation resistance, compounds 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 are preferred.

[0290] Specific examples of tetraalkyl quaternary ammonium salts include tetraalkyl quaternary ammonium salts represented by general formula (IIa-1) and trialkyl ammonium salts containing alkyl ether groups represented by general formula (IIa-2). (where R) 1a R 2a and X － Same as above; x and y may represent integers from 0 to 4, either the same or different, and x + y = 4. (where R) 5a R represents an alkyl group having 1 to 6 carbon atoms; 6a R represents a divalent hydrocarbon group with 1 to 6 carbon atoms; 7a Indicates an alkyl group with 1 to 4 carbon atoms; z indicates 1 or 2; X － (This indicates anion.) By introducing alkyl ether groups, viscosity can be reduced.

[0291] Anion X － It can be either an inorganic anion or an organic anion. Examples of inorganic anions include AlCl4. － BF4 － PF6 － AsF6 － TaF6 － I － SbF6 － Examples of organic anions include 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.

[0292] Among these, BF4 is preferred from the perspective of good oxidation resistance and ion dissociation properties. － PF6 － AsF6 － SbF6 － .

[0293] Preferred 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 can be used (Et represents ethyl, and Me represents methyl).

[0294] (IIb) Spirocyclic bipyridinium salts Preferred examples include spirocyclic bipyridinium salts represented by general formula (IIb-1), spirocyclic bipyridinium salts represented by general formula (IIb-2), or spirocyclic bipyridinium salts represented by general formula (IIb-3). (where R) 8a and R 9a Whether the two are the same or different, they both indicate alkyl groups with 1 to 4 carbon atoms; X － (n1 represents an anion; n2 represents an integer from 0 to 5.) (where R) 10a and R 11a Whether the two are the same or different, they both indicate alkyl groups with 1 to 4 carbon atoms; X － (n represents anion; n3 represents an integer from 0 to 5; n4 represents an integer from 0 to 5.) (where R) 12a and R 13a Whether the two are the same or different, they both indicate alkyl groups with 1 to 4 carbon atoms; X － (n represents anion; n5 represents an integer from 0 to 5; n6 represents an integer from 0 to 5.) Furthermore, from the viewpoint of improving oxidation resistance, it is also preferable to be a substance in which some or all of the hydrogen atoms of the spirocyclic bipyridinium salt are replaced by fluorine atoms and / or fluorinated alkyl groups having 1 to 4 carbon atoms.

[0295] Anion X － The preferred specific example is the same as in (IIa). From the viewpoint of high dissociation and low internal resistance at high voltage, BF4 is preferred. － PF6－ (CF3SO2)2N － Or (C2F5SO2)2N － .

[0296] Preferred examples of spirocyclic bipyridinium salts include: wait.

[0297] This spirocyclic bipyridinium salt exhibits excellent solubility, oxidation resistance, and ion conductivity in solvents.

[0298] (IIc) Imidazolium salts The imidazolium salts represented by general formula (IIc) are preferred examples. (where R) 14a and R 15a Whether the two are the same or different, they both indicate alkyl groups with 1 to 6 carbon atoms; X － (This indicates anion.) Furthermore, from the viewpoint of improving oxidation resistance, it is also preferable to be 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.

[0299] Anion X － The preferred specific example is the same as (IIa).

[0300] As a preferred specific example, the following can be listed: wait.

[0301] This imidazolium salt excels in low viscosity and good solubility.

[0302] (IId): N-alkylpyridinium salt Preferred examples are N-alkylpyridinium salts represented by general formula (IId). (where R) 16a Indicates an alkyl group having 1 to 6 carbon atoms; X － (This indicates anion.) Furthermore, from the viewpoint of improving oxidation resistance, it is also preferable to be a substance in which some or all of the hydrogen atoms of the N-alkylpyridinium salt are replaced by fluorine atoms and / or fluorinated alkyl groups having 1 to 4 carbon atoms.

[0303] Anion X － The preferred specific example is the same as (IIa).

[0304] Preferred examples of N-alkylpyridinium salts include, for example: wait.

[0305] This N-alkylpyridinium salt exhibits excellent properties in terms of low viscosity and good solubility.

[0306] (IIe)N,N-dialkylpyrrolidine onium salt Preferred examples are N,N-dialkylpyrrolidone onium salts represented by general formula (IIe). (where R) 17a and R 18a Whether the two are the same or different, they both indicate alkyl groups with 1 to 6 carbon atoms; X － (This indicates anion.) Furthermore, from the viewpoint of improving oxidation resistance, it is also preferable to be a substance in which some or all of the hydrogen atoms of the N,N-dialkylpyrrolidine onium salt are replaced by fluorine atoms and / or fluorinated alkyl groups having 1 to 4 carbon atoms.

[0307] Anion X － The preferred specific example is the same as (IIa).

[0308] Preferred examples of N,N-dialkylpyrrolidine onium salts include, for example: wait.

[0309] This N,N-dialkylpyrrolidine onium salt exhibits excellent properties in terms of low viscosity and good solubility.

[0310] Among these ammonium salts, (IIa), (IIb), and (IIc) are preferred in terms of good solubility, oxidation resistance, and ion conductivity, and are further preferred. .

[0311] (In the formula, Me is methyl; Et is ethyl; X) － x, y are the same as in equation (IIa-1). Alternatively, lithium salts can be used as the electrolyte salt for double-layer capacitors. Preferred lithium salts include, for example, LiPF6, LiBF4, LiN(FSO2)2, LiAsF6, LiSbF6, and LiN(SO2C2H5)2.

[0312] Magnesium salts can also be used to further improve capacity. Preferred magnesium salts include, for example, Mg(ClO4)2 and Mg(OOC2H5)2.

[0313] When the electrolyte salt is the aforementioned ammonium salt, from the viewpoint of low-temperature characteristics and initial internal resistance, the concentration is preferably 0.7 mol / L or more. The concentration of the aforementioned electrolyte salt is more preferably 0.9 mol / L or more.

[0314] 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.

[0315] When the ammonium salt is triethylmethylammonium tetrafluoroborate (TEMABF4), its concentration is preferably 0.7 to 1.5 mol / L, considering its excellent low-temperature properties.

[0316] In addition, when the substance is spiropyridinium tetrafluoroborate (SBPBF4), from the viewpoint of the performance of the electrochemical device, a concentration of 0.7 to 2.0 mol / L is preferred.

[0317] The electrolyte of the present invention preferably further contains compound (2) represented by general formula (2).

[0318] General formula (2): (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" indicates that it contains at least one group of H, C, O, or F, n22 is 0 or 1, Y 21 and Z 21 They can combine to form a ring. When the electrolyte contains compound (2), even under high temperature storage conditions, the capacity retention rate is not easily reduced further and the amount of gas generated is not easily increased further.

[0319] When n21 is 2 or 3, there are 2 or 3 X's. 21 They can be the same or different.

[0320] In Y 21 and Z 21 In the case of multiple Ys, there are multiple Ys 21 and Z 21 They can be the same or different.

[0321] As X 21 From the perspective of electrochemical device performance, the preferred option is -CY. 21 Z 21 - (where Y) 21 and Z 21 (as described above) or -CY 21 =CZ 21 - (where Y)21 and Z 21 The groups shown above.

[0322] As Y 21 From the viewpoint of the performance of electrochemical devices, it is preferred to select at least one of H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-.

[0323] As Z 21 From the viewpoint of the performance of electrochemical devices, it is preferred to select at least one of H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-.

[0324] Or, Y 21 and Z 21 They can combine 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.

[0325] Hereinafter, specific examples of compound (2) will be described. In the following examples, "analogous" refers to an anhydride formed by replacing a part of the structure of the illustrated anhydride with another structure without departing from the spirit of the present invention. For example, dimers, trimers and tetramers composed of multiple anhydrides can be listed, or structural isomers with the same number of carbon atoms in the substituents but with branches, or compounds with different binding sites between the substituents and the anhydride.

[0326] 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.

[0327] Specific examples of acid anhydrides that form six-membered ring structures include: cyclohexane dicarboxylic anhydrides (such as cyclohexane-1,2-dicarboxylic anhydride), 4-cyclohexene-1,2-dicarboxylic anhydride, glutaric anhydride, pentene anhydride, 2-phenylglutaric anhydride, and their analogues.

[0328] 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.

[0329] 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.

[0330] As compound (2), from the viewpoint of the performance of electrochemical devices, the preferred compounds are 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, phenyl succinic anhydride, 2-phenylglutaric anhydride, maleic anhydride, methyl maleic anhydride, trifluoromethyl maleic anhydride, phenyl maleic anhydride, succinic anhydride, methyl succinic anhydride, dimethyl succinic anhydride, trifluoromethyl succinic anhydride, monofluoro succinic anhydride, tetrafluoro succinic anhydride, etc., more preferably maleic anhydride, methyl maleic anhydride, trifluoromethyl maleic anhydride, succinic anhydride, methyl succinic anhydride, trifluoromethyl succinic anhydride, tetrafluoro succinic anhydride, and even more preferably maleic anhydride and succinic anhydride.

[0331] From the viewpoint of the performance of electrochemical devices, compound (2) is preferably selected from at least one of compound (3) of general formula (3) and compound (4) of general formula (4).

[0332] (3) (where X) 31 ~X 34 "Same" or "different" indicates that it contains at least one of the following groups: H, C, O, or F. (4) (where X) 41 and X 42 "Same" or "different" indicates that it contains at least one of the following groups: H, C, O, or F. As X31 ~X 34 Preferably, it is selected from at least one of alkyl, fluoroalkyl, alkenyl and fluoroalkenyl groups, either the same or different. 31 ~X 34 The number of carbon atoms is preferably 1 to 10, more preferably 1 to 3.

[0333] As X 31 ~X 34 More preferably, it is selected from at least one of H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-, either the same or different.

[0334] As X 41 and X 42 Preferably, it is selected from at least one of alkyl, fluoroalkyl, alkenyl and fluoroalkenyl groups, either the same or different. 41 and X 42 The number of carbon atoms is preferably 1 to 10, more preferably 1 to 3.

[0335] As X 41 and X 42 More preferably, it is selected from at least one of H-, F-, CH3-, CH3CH2-, CH3CH2CH2-, CF3-, CF3CF2-, CH2FCH2- and CF3CF2CF2-, either the same or different.

[0336] Compound (3) is preferably any of the following compounds. Compound (4) is preferably any of the following compounds. From the viewpoint that the capacity retention rate is not likely to decrease further and the amount of gas generated is not likely to increase further when the electrolyte is stored at high temperatures, it is preferable that the electrolyte contains 0.0001 to 15% by mass of compound (2). The content of compound (2) is more preferably 0.01 to 10% by mass, more preferably 0.1 to 3% by mass, and particularly preferably 0.1 to 1.0% by mass.

[0337] In the case where the electrolyte contains both compounds (3) and (4), from the viewpoint that the capacity retention rate is not likely to decrease further and the amount of gas generated is not likely to increase further even when stored at high temperature, the electrolyte preferably contains 0.08 to 2.50% by mass of compound (3) and 0.02 to 1.50% by mass of compound (4) relative to the electrolyte, and more preferably contains 0.80 to 2.50% by mass of compound (3) and 0.08 to 1.50% by mass of compound (4).

[0338] The electrolyte of the present invention may contain at least one nitrile compound selected from those represented by general formulas (1a), (1b) and (1c). (where R) a and R b Each group independently represents a hydrogen atom, a cyano (CN) group, a halogen atom, an alkyl group, or a group in which at least some hydrogen atoms of an alkyl group are replaced by halogen atoms. n represents an integer from 1 to 10. (where R) c Indicates a hydrogen atom, a halogen atom, an alkyl group, a group in which at least some hydrogen atoms of an alkyl group are replaced by halogen atoms, or NC-R c1 -X c1 - (R) c1 Indicates alkylene, X c1 The group indicated by the symbol (representing an oxygen atom or a sulfur atom). R d and R e Each group independently represents a hydrogen atom, a halogen atom, an alkyl group, or a group in which at least some hydrogen atoms of an alkyl group are replaced by halogen atoms. m represents an integer from 1 to 10. (where R) f R g R h and R i Each of these groups independently represents a cyano (CN) group, a hydrogen atom (H), 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. However, R f R g R h and R i At least one of them is a cyano group. l represents an integer from 1 to 3. This improves the high-temperature storage characteristics of electrochemical devices. The aforementioned nitrile compounds can be used alone or in any combination and ratio of two or more.

[0339] In the above general formula (1a), R a and R b A group that is independently a hydrogen atom, a cyano (CN) group, a halogen atom, an alkyl group, or at least a portion of the hydrogen atoms of an alkyl group being replaced by a halogen atom.

[0340] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Fluorine is preferred.

[0341] As an alkyl group, it is preferred to be an alkyl group having 1 to 5 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc.

[0342] As a group in which at least a portion of the hydrogen atoms of an alkyl group are replaced by halogen atoms, examples of alkyl groups in which at least a portion of the hydrogen atoms are replaced by halogen atoms can be listed above.

[0343] 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 and R b They can combine with each other to form a ring structure (e.g., the cyclohexane ring).

[0344] R a and R b Preferably, it contains hydrogen atoms or alkyl groups.

[0345] 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. R b Similarly, n is preferably an integer from 1 to 7, and more preferably an integer from 2 to 5.

[0346] From the viewpoint of the performance of electrochemical devices, dinitrile and trimethylnitrile are preferred as nitrile compounds represented by the above general formula (1a).

[0347] 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, dicyclohexyl-1,1-dicarboxylon, dicyclohexyl-2,2-dicarboxylon, dicyclohexyl-3,3-dicarboxylon, 2,5-dimethyl-2,5-hexanedionitrile, 2,3-diisobutyl-2,3-dimethylbutadionitrile, 2,2-di... Isobutyl-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-dibutyl-3,3-dimethylglutaronitrile Cyanooctane, 2,8-dicyanonane, 1,6-dicyanodecane, 1,2-dicyanobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene, 3,3′-(ethylenedioxy)dipropionitrile, 3,3′-(ethylenedisulfide)dipropionitrile, 3,9-bis(2-cyanoethyl)-2,4,8,10-tetraoxaziro[5,5]undecane, butyronitrile, phthalonitrile, etc. Among them, butyronitrile, glutaronitrile, and adiponitrile are particularly preferred.

[0348] In addition, specific examples of triformonitriles include pentanetriformonitriles, propanetriformonitriles, 1,3,5-hexanetriformonitriles, 1,3,6-hexanetriformonitriles, heptanetriformonitriles, 1,2,3-propanetriformonitriles, 1,3,5-pentanetriformonitriles, cyclohexanetriformonitriles, tricyanoethylamine, tricyanoethoxypropane, tricyanoethylene, tri(2-cyanoethyl)amine, etc., with 1,3,6-hexanetriformonitriles and cyclohexanetriformonitriles being particularly preferred, and cyclohexanetriformonitriles being the most preferred.

[0349] In the above general formula (1b), R c It is 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 The group represented by R (indicating oxygen or sulfur atoms) d and R e A group that is independently a hydrogen atom, a halogen atom, an alkyl group, or at least a portion of the hydrogen atoms of an alkyl group are replaced by halogen atoms.

[0350] Regarding halogen atoms, alkyl groups, and groups in which at least some of the hydrogen atoms of an alkyl group are replaced by halogen atoms, examples of groups exemplified for the above general formula (1a) can be listed.

[0351] The above NC-R c1 -X c1 R in - c1 It is an alkylene group. Preferably, it is an alkylene group having 1 to 3 carbon atoms.

[0352] Preferred R c R d and R e A group that is independently a hydrogen atom, a halogen atom, an alkyl group, or at least a portion of the hydrogen atoms of an alkyl group are replaced by halogen atoms.

[0353] Preferred R c R d and R e At least one of them is a group in which at least a portion of the hydrogen atoms of a halogen atom or an alkyl group is replaced by a halogen atom, more preferably a group in which at least a portion of the hydrogen atoms of a fluorine atom or an alkyl group is replaced by a fluorine atom.

[0354] 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 and R e They can combine with each other to form a ring structure (e.g., the cyclohexane ring).

[0355] 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 the same, or at least partially different. R e Similarly, m is preferably an integer from 2 to 7, and more preferably an integer from 2 to 5.

[0356] Examples of nitrile compounds represented by the above general formula (1b) include acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 3-methoxypropionitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanonitrile, cyclopentaneformitrile, cyclohexaneformitrile, 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.

[0357] In the above general formula (1c), R f R g R h and R iEach is independently 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.

[0358] Regarding halogen atoms, alkyl groups, and groups in which at least some of the hydrogen atoms of an alkyl group are replaced by halogen atoms, examples of groups exemplified for the above general formula (1a) can be listed.

[0359] As a cyano-containing group, in addition to cyano groups, groups in which at least some of the hydrogen atoms of an alkyl group are replaced by cyano groups can also be listed. As an alkyl group in this case, groups exemplified for the above general formula (1a) can be listed.

[0360] R f R g R h and R i At least one of them is a cyano-containing 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 cyano-containing group. In R h and R i In the case where R is a cyano-containing group, f and R g Hydrogen atoms are preferred.

[0361] In the above general formula (1c), l is an integer from 1 to 3. When l is 2 or more, l R f They can be completely the same, or at least partially different. R g Similarly, l is preferably an integer from 1 to 2.

[0362] Examples of nitrile compounds represented by the above general formula (1c) include 3-hexenonitrile, hexadienoic acid (Mucononitrile), maleic acid, fumaric acid, acrylonitrile, methacrylonitrile, crotonitrile, 3-methylcrotonitrile, 2-methyl-2-butenonitrile, 2-pentenonitrile, 2-methyl-2-pentenonitrile, 3-methyl-2-pentenonitrile, and 2-hexenonitrile, with 3-hexenonitrile and hexadienoic acid being preferred, and 3-hexenonitrile being particularly preferred.

[0363] 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.

[0364] The electrolyte of the present invention may contain compounds 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, triisocyanates, etc.

[0365] Specific examples of monoisocyanates include isocyanate methane, isocyanate ethane, 1-isocyanate propane, 1-isocyanate butane, 1-isocyanate pentane, 1-isocyanate hexane, 1-isocyanate heptane, 1-isocyanate octane, 1-isocyanate nonane, 1-isocyanate decane, isocyanate cyclohexane, 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 acrylate, ethyl 2-isocyanate methacrylate, and ethyl isocyanate.

[0366] 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, 2,3-difluorobutane 1,4-diisocyanate, 2-pentene 1,5-diisocyanate, 2-methylpentane 1,5-diisocyanate, 2-hexene 1,6-diisocyanate, 3-hexene 1,6-diisocyanate, 3-fluorohexane 1,6-diisocyanate, 3,4-difluorohexane 1,6-diisocyanate, toluene diisocyanate, xylene diisocyanate, tolylene Diisocyanate, 1,2-bis(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-3,3′-diisocyanate, dicyclohexylmethane-1,1′-diisocyanate, dicyclohexylmethane-2,2′-diisocyanate, dicyclohexylmethane-3,3′-diisocyanate, dicyclohexylmethane-1,1′-diisocyanate, dicyclohexylmethane-2,2′-diisocyanate, dicyclohexylmethane-3,3′-diisocyanate, dicyclohexylmethane-1,2 ... Hexylmethane-4,4′-diisocyanate, isophorone diisocyanate, bicyclo[2.2.1]heptane-2,5-dimethylbis(methyl=isocyanate), bicyclo[2.2.1]heptane-2,6-dimethylbis(methyl=isocyanate), 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, 1,4-phenylene diisocyanate, octamethylene diisocyanate, tetramethylene diisocyanate, etc.

[0367] 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 hexa-1-yl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 4-(isocyanate methyl)octamethylene diisocyanate.

[0368] Among them, 1,6-diisocyanate hexane, 1,3-bis(isocyanate methyl)cyclohexane, 1,3,5-tris(6-isocyanate hexa-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 are preferred from the viewpoint of keeping the manufacturing cost of the electrolyte low. From a technical point of view, they also help to form a stable film-like structure and are more suitable for use.

[0369] 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. When the isocyanate content is above this lower limit, it can sufficiently improve the cycle characteristics of the non-aqueous electrolyte secondary battery. Furthermore, when it is below this upper limit, it can prevent an increase in the initial resistance of the non-aqueous electrolyte secondary battery. 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 more preferably 0.8% by mass or less, further preferably 0.7% by mass or less, particularly preferably 0.6% by mass or less.

[0370] 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.

[0371] 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.

[0372] Specific examples of unsaturated cyclic sulfonates include 1-propene-1,3-sulfonolactone, 2-propene-1,3-sulfonolactone, 1-fluoro-1-propene-1,3-sulfonolactone, 2-fluoro-1-propene-1,3-sulfonolactone, 3-fluoro-1-propene-1,3-sulfonolactone, 1-fluoro-2-propene-1,3-sulfonolactone, 2-fluoro-2-propene-1,3-sulfonolactone, 3-fluoro-2-propene-1,3-sulfonolactone, 1-methyl-1-propene-1,3-sulfonolactone, and 2-methyl-1-propene-1,3-sulfonolactone. Ester, 3-methyl-1-propene-1,3-sulfonolactone, 1-methyl-2-propene-1,3-sulfonolactone, 2-methyl-2-propene-1,3-sulfonolactone, 3-methyl-2-propene-1,3-sulfonolactone, 1-butene-1,4-sulfonolactone, 2-butene-1,4-sulfonolactone, 3-butene-1,4-sulfonolactone, 1-fluoro-1-butene-1,4-sulfonolactone, 2-fluoro-1-butene-1,4-sulfonolactone, 3-fluoro-1-butene-1,4-sulfonolactone, 4-fluoro-1-butene-1,4-sulfonolactone 1-Fluoro-2-butene-1,4-sulfonolactone, 2-Fluoro-2-butene-1,4-sulfonolactone, 3-Fluoro-2-butene-1,4-sulfonolactone, 4-Fluoro-2-butene-1,4-sulfonolactone, 1,3-propenesulfonolactone, 1-Fluoro-3-butene-1,4-sulfonolactone, 2-Fluoro-3-butene-1,4-sulfonolactone, 3-Fluoro-3-butene-1,4-sulfonolactone, 4-Fluoro-3-butene-1,4-sulfonolactone, 1-Methyl-1-butene-1,4-sulfonolactone, 2-Methyl-1-butene-1,4-sulfonolactone 3-Methyl-1-butene-1,4-sulfonolactone, 4-methyl-1-butene-1,4-sulfonolactone, 1-methyl-2-butene-1,4-sulfonolactone, 2-methyl-2-butene-1,4-sulfonolactone, 3-methyl-2-butene-1,4-sulfonolactone, 4-methyl-2-butene-1,4-sulfonolactone, 1-methyl-3-butene-1,4-sulfonolactone, 2-methyl-3-butene-1,4-sulfonolactone, 3-methyl-3-butene-1,4-sulfonolactone, 4-methyl-3-butene-1,4-sulfonolactone, etc.

[0373] From the viewpoint of easy availability and facilitating the formation of a stable film-like structure, 1,3-propanesulfonyl lactone, 1-fluoro-1,3-propanesulfonyl lactone, 2-fluoro-1,3-propanesulfonyl lactone, 3-fluoro-1,3-propanesulfonyl lactone, and 1-propylene-1,3-sulfonyl lactone are more suitable. The content of the cyclic sulfonate is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the invention; however, it is preferably 0.001% by mass or more and 3.0% by mass or less relative to the electrolyte.

[0374] When the content of cyclic sulfonate is above the lower limit, it can sufficiently improve the cycle characteristics of non-aqueous electrolyte secondary batteries. Furthermore, when 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 more preferably 2.5% by mass or less, further preferably 2.0% by mass or less, particularly preferably 1.8% by mass or less.

[0375] The electrolyte of the present invention may also contain polyoxyethylene with a weight average molecular weight of 2000 to 4000 and terminally having -OH, -OCOOH or -COOH.

[0376] By incorporating such compounds, the stability of the electrode interface is improved, thereby enhancing the characteristics of electrochemical devices.

[0377] Examples of the aforementioned polyoxyethylene compounds include, for instance, polyoxyethylene monohydric alcohol, polyoxyethylene carboxylic acid, polyoxyethylene dihydric alcohol, polyoxyethylene dicarboxylic acid, polyoxyethylene trihydric alcohol, and polyoxyethylene tricarboxylic acid. These can be used individually or in combination of two or more.

[0378] From the viewpoint of improving the characteristics of electrochemical devices, mixtures of polyoxyethylene monohydric alcohol and polyoxyethylene dihydric alcohol, and mixtures of polyvinyl carboxylic acid and polyvinyl dicarboxylic acid are preferred.

[0379] If the weight-average molecular weight of the aforementioned polyoxyethylene is too low, it may easily undergo oxidative decomposition. A more preferable weight-average molecular weight is 3000–4000.

[0380] The weight-average molecular weight mentioned above can be determined by conversion from polystyrene using gel permeation chromatography (GPC).

[0381] From the perspective of electrochemical device performance, the preferred content of the aforementioned polyoxyethylene in the electrolyte is 1×10⁻⁶. －6 ~1×10 －2 mol / kg.

[0382] The preferred content of the aforementioned polyoxyethylene is 5 × 10⁻⁶. －6 Above mol / kg.

[0383] The electrolyte of the present invention may further contain fluorinated saturated cyclic carbonates, unsaturated cyclic carbonates, anti-overcharge agents, and other known additives as additives. This facilitates the suppression of performance degradation in electrochemical devices.

[0384] As fluorinated saturated cyclic carbonates, compounds represented by the above general formula (A) can be listed. Among them, 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 can be used alone, or two or more can be used in any combination and proportion.

[0385] From the viewpoint of the performance of electrochemical devices, 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.

[0386] Examples of unsaturated cyclic carbonates include vinylene carbonates, ethylene carbonates substituted with substituents having aromatic rings, carbon-carbon double bonds or carbon-carbon triple bonds, phenyl carbonates, vinyl carbonates, allyl carbonates, and catechol carbonates.

[0387] 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.

[0388] Specific examples of ethylene carbonates substituted with substituents having aromatic rings, carbon-carbon double bonds, or carbon-carbon 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-dieethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate, and 4-allyl-5-vinyl ethylene carbonate. - 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.

[0389] Among these, vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl vinylene carbonate, 4,5-divinyl vinylene carbonate, 4-methyl-5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, 4-methyl-5-allyl vinylene carbonate, 4-allyl-5-vinyl vinylene carbonate, ethynyl vinylene carbonate, 4,5-diethynyl vinylene carbonate, 4-methyl-5-ethynyl vinylene carbonate, and 4-vinyl-5-ethynyl vinylene carbonate are preferred as unsaturated cyclic carbonates. Furthermore, vinylene carbonate, vinyl vinylene carbonate, and ethynyl vinylene carbonate are particularly preferred, and most preferred, as they can form a more stable interfacial protective film.

[0390] 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 to 250. Within this range, it is easy to ensure the solubility of the unsaturated cyclic carbonate in 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.

[0391] There are no particular restrictions on the manufacturing method of unsaturated cyclic carbonates; any known method can be chosen.

[0392] Unsaturated cyclic carbonates can be used alone or in combination or proportion of two or more.

[0393] 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. Within the above ranges, electrochemical devices using the electrolyte readily exhibit a sufficiently improved cycle performance, and easily avoid conditions such as reduced high-temperature storage characteristics, increased gas generation, and decreased discharge capacity retention.

[0394] In addition to the non-fluorinated unsaturated cyclic carbonates mentioned above, fluorinated unsaturated cyclic carbonates may also be appropriately used as unsaturated cyclic carbonates.

[0395] 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 1 or more. Typically, it has 6 or fewer fluorine atoms, preferably 4 or fewer, and most preferably 1 or 2.

[0396] Examples of fluorounsaturated cyclic carbonates include fluoroethylene carbonate derivatives and fluoroethylene carbonate derivatives substituted with substituents having aromatic rings or carbon-carbon double bonds.

[0397] 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.

[0398] 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-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, and 4,5- Difluoro-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.

[0399] Among them, as fluorinated unsaturated cyclic carbonates, 4-fluoroethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-allyl-5-fluoroethylene carbonate, 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, and 4,5-difluoro-4,5-diallylethylene carbonate can form a stable interfacial protective film and are therefore more suitable for use.

[0400] There are no particular limitations on the molecular weight of the fluorinated unsaturated cyclic carbonate, and it can be arbitrary as long as it does not significantly impair the effects of the present invention. The molecular weight is preferably 50 or more and 500 or less. Within this range, it is easy to ensure the solubility of the fluorinated unsaturated cyclic carbonate in the electrolyte.

[0401] There are no particular restrictions on the manufacturing method of fluorinated unsaturated cyclic carbonates; any known method can be selected. A molecular weight of 100 or more is more preferred, and even more preferred to be 200 or less.

[0402] Fluorinated unsaturated cyclic carbonates can be used alone, or two or more can be used in any combination and 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 present invention. The content of the fluorinated unsaturated cyclic carbonates in 100% by mass of the electrolyte is preferably 0.001% by mass or more, 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 significant improvement in cycle characteristics, and easily avoid conditions such as decreased high-temperature storage characteristics, increased gas generation, and reduced discharge capacity retention.

[0403] The electrolyte of this invention may also contain compounds with triple bonds. There is no particular limitation on the type of compound, as long as it has one or more triple bonds within its molecule.

[0404] As specific examples of compounds with triple bonds, the following compounds can be listed: 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. 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; 2-Prolyne acetate, 2-Prolyne propionate, 2-Prolyne butyrate, 2-Prolyne benzoate, 2-Prolyne cyclohexanecarboxylate, 1,1-Dimethyl-2-Prolyne acetate, 1,1-Dimethyl-2-Prolyne propionate, 1,1-Dimethyl-2-Prolyne butyrate, 1,1-Dimethyl-2-Prolyne benzoate, 1,1-Dimethyl-2-Prolyne cyclohexanecarboxylate, 2-Butyne acetate, 3-Butyne acetate, 2-Pentyne acetate, 3-Pentyne acetate, 4-Pentyne acetate, methyl acrylate Ethyl acrylate, 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-propynic acid-2-propylene ester, 2-propynic acid-2-butenyl ester, 2-propynic acid-3-butenyl Ester, methyl 2-butynate, ethyl 2-butynate, propyl 2-butynate, vinyl 2-butynate, 2-butynate-2-propylene, 2-butynate-2-butenyl, 2-butynate-3-butenyl, methyl 3-butynate, ethyl 3-butynate, propyl 3-butynate, vinyl 3-butynate, 2-butynate-2-propylene, 2-butynate-2-butenyl, 3-butynate-3-butenyl, methyl 2-pentynate, ethyl 2-pentynate, propyl 2-pentynate, vinyl 2-pentynate, 2-pentynate-2-propylene, 2-pentynate Monocarboxylic acid esters, fumarates, trimethylacetate, and ethyl 3-pentynolate, ethyl 3-pentynolate, propyl 3-pentynolate, vinyl 3-pentynolate, 2-propenyl 3-pentynolate, 2-butenyl 3-pentynolate, 3-butenyl 3-pentynolate, methyl 4-pentynolate, ethyl 4-pentynolate, propyl 4-pentynolate, vinyl 4-pentynolate, 2-propenyl 4-pentynolate, 2-butenyl 4-pentynolate, 3-butenyl 4-pentynolate, etc. 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 dicyclohexane carboxylate, hexahydrobenzo[1,3,2]dioxothiacyclopentane-2-oxide (1,2-cyclohexanediol, 2,2-dioxo-1,2-dioxothiacyclopentane-4-ylacetate, 2,2-dioxo-1,2-dioxothiacyclopentane-4-ylacetate, etc. dicarboxylic acid esters); Methyl-2-propynyl oxalate, ethyl-2-propynyl oxalate, propyl-2-propynyl oxalate, 2-propynyl vinyl oxalate, allyl-2-propynyl oxalate, di-2-propynyl oxalate, 2-butynyl methyl oxalate, 2-butynyl ethyl oxalate, 2-butynyl propyl oxalate, 2-butynyl vinyl oxalate, allyl-2-butynyl oxalate, di-2-butynyl oxalate, 3-butynyl methyl oxalate, 3-butynyl ethyl oxalate, 3-butynyl propyl oxalate, 3-butynyl vinyl oxalate, allyl-3-butynyl oxalate, di-3-butynyl oxalate, etc., are all oxalate diesters. 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; Methyl(2-propenyl)phosphino-2-propynyl ester, 2-butenyl(methyl)phosphino-2-propynyl ester, bis(2-propenyl)phosphino-2-propynyl ester, bis(3-butenyl)phosphino-2-propynyl ester, methyl(2-propenyl)phosphino-1,1-dimethyl-2-propynyl ester, 2-butenyl(methyl)phosphino-1,1-dimethyl-2-propynyl ester, bis(2-propenyl)phosphino-1,1-dimethyl-2-propynyl Esters, and bis(3-butenyl)phosphonic acid-1,1-dimethyl-2-propynyl ester, methyl(2-propynyl)phosphonic acid-2-propenyl ester, methyl(2-propynyl)phosphonic acid-3-butenyl ester, bis(2-propynyl)phosphonic acid-2-propenyl ester, bis(2-propynyl)phosphonic acid-3-butenyl ester, 2-propynyl(2-propenyl)phosphonic acid-2-propenyl ester, and 2-propynyl(2-propenyl)phosphonic acid-3-butenyl ester, etc. 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) (2-propenyl) ester Phosphonates include (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. Phosphate esters including (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.

[0405] Among these, compounds with alkynyl groups are preferred because they form a negative electrode film more stably in the electrolyte.

[0406] Furthermore, considering the improvement of 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, methyl oxalate-2-propynyl ester, and di-2-propynyl oxalate are particularly preferred.

[0407] The aforementioned compounds with triple bonds can be used alone, or two or more can be used in any combination and proportion. There is no limitation on the amount of the compound with triple bonds relative to the overall electrolyte of the present invention; it is arbitrary as long as it does not significantly impair the effects of the present invention. The concentration relative to the electrolyte of the present invention is typically 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and typically 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less. When the above ranges are met, the output characteristics, load characteristics, cycle characteristics, high-temperature storage characteristics, and other effects are further improved.

[0408] In order to effectively prevent battery rupture and fire when electrochemical devices using electrolytes reach overcharge or other states, an anti-overcharge agent can be used in the electrolyte of the present invention.

[0409] As anti-overfill agents, examples include: biphenyl, o-terphenyl, m-terphenyl, p-terphenyl and other unsubstituted or alkyl-substituted terphenyl derivatives; partially hydrides of unsubstituted or alkyl-substituted terphenyl derivatives; cyclohexylbenzene, tert-butylbenzene, tert-pentylbenzene, diphenyl ether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindenium, cyclopentylbenzene, cyclohexylbenzene, isopropylbenzene, 1,3-diisopropylbenzene, 1,4-diisopropylbenzene, tert-butylbenzene, tert-pentylbenzene, tert-hexylbenzene, anisole and other aromatic compounds; 2-fluorobiphenyl, 4-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene, etc. Partially fluorinated derivatives of the above-mentioned aromatic compounds such as fluorotoluene and trifluorotoluene; 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 methylphenyl carbonate; 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. Among them, preferred aromatic compounds include biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, tert-butylbenzene, tert-amylbenzene, diphenyl ether, dibenzofuran, etc., diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindenium, 3-propylphenylacetate, 2-ethylphenylacetate, benzylphenylacetate, methylphenylacetate, benzyl acetate, diphenyl carbonate, methylphenyl carbonate, etc. These can be used individually or in combination of two or more. When two or more are used together, from the viewpoint of balancing overcharge prevention characteristics and high-temperature storage characteristics, a combination of cyclohexylbenzene and tert-butylbenzene or tert-amylbenzene, and the use of at least one non-oxygen-containing aromatic compound selected from biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, tert-butylbenzene, tert-amylbenzene, etc., and at least one oxygen-containing aromatic compound selected from diphenyl ether, dibenzofuran, etc.

[0410] 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. (In general formula (6), R) 61 R 62 Each can be independently represented as a hydrocarbon group having 1 to 15 carbon atoms that can have substituents. R 61 R 62When the hydrocarbon group is monovalent, its type is not particularly limited. For example, it can be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a group formed by the combination of an aliphatic and an aromatic hydrocarbon group. 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; when chain-like, it can be straight-chain or branched, or a group formed by the combination of chains and rings. Additionally, R... 61 and R 62 They can be the same or different.

[0411] Additionally, in the hydrocarbon group R 61 R 62 When substituents are present, 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 those with functional groups such as ester, cyano, carbonyl, and ether groups, with cyano and carbonyl groups being preferred. Hydrocarbon group R 61 R 62 It may have only one of these substituents, or it may have two or more. When it has two or more substituents, these substituents may be the same or different from each other.

[0412] hydrocarbon group R 61 R 62 Each of them typically has 1 or more carbon atoms; and typically 15 or less, preferably 12 or less, more preferably 10 or less, and even more preferably 9 or less. In R 1 With R 2 When they combine to form a divalent hydrocarbon group, 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. Furthermore, in the hydrocarbon group R... 61 R 62 When R has a carbon-containing substituent, it is preferable to include the substituent. 61 R 62 The total number of carbon atoms meets the above range.

[0413] Hereinafter, specific examples of the anhydrides represented by the general formula (6) above will be described. In the following examples, "analogous" refers to an anhydride formed by replacing a part of the structure of the illustrated anhydride with another structure without departing from the spirit of the present invention. For example, dimers, trimers and tetramers composed of multiple anhydrides can be listed, or structural isomers with the same number of carbon atoms in the substituents but with branches, etc., or compounds with different binding sites between the substituents and the anhydride.

[0414] First, the following lists R61 R 62 Specific examples of the same acid anhydride.

[0415] As R 61 R 62 Specific examples of anhydrides that are chain-like alkyl groups 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, etc., and their analogues.

[0416] As R 61 R 62 Specific examples of cyclic alkyl anhydrides include cyclopropionic acid anhydride, cyclopentocarboxylic acid anhydride, cyclohexanecarboxylic acid anhydride, and their analogues.

[0417] As R 61 R 62 Specific examples of alkenyl anhydrides include: acrylic anhydride, 2-methylacrylic anhydride, 3-methylacrylic 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-cyclopentenecarboxylic anhydride, 3-cyclopentenecarboxylic anhydride, 4-cyclopentenecarboxylic anhydride, and their analogues.

[0418] 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.

[0419] As R 61 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.

[0420] Additionally, as R 61 R62 Examples of acid anhydrides substituted with halogen atoms are listed below, with a focus on those substituted with fluorine atoms. However, acid anhydrides formed by replacing some or all of these fluorine atoms with chlorine, bromine, or iodine atoms are also included in the illustrated compounds.

[0421] As R 61 R 62 Examples of acid anhydrides consisting of chain 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.

[0422] As R 61 R 62 Examples of anhydrides of cyclic alkyl groups substituted with halogen atoms include 2-fluorocyclopentanediol, 3-fluorocyclopentanediol, 4-fluorocyclopentanediol, and their analogues.

[0423] As R 61 R 62 Examples of 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.

[0424] As R 61 R 62 Examples of acid anhydrides with halogen-substituted alkynyl groups 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.

[0425] As R 61 R62 Examples of aryl anhydrides substituted with halogen atoms include 4-fluorobenzoic anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, 4-trifluoromethylbenzoic anhydride, and their analogues.

[0426] As R 61 R 62 Examples of substituent-containing acid anhydrides having functional groups such as esters, nitriles, ketones, and ethers include: methoxyformic anhydride, ethoxyformic anhydride, methyl oxalic anhydride, ethyl oxalic anhydride, 2-cyanoacetic anhydride, 2-oxopropionic anhydride, 3-oxobutyric anhydride, 4-acetylbenzoic anhydride, methoxyacetic anhydride, 4-methoxybenzoic anhydride, and their analogues.

[0427] Next, the following lists R 61 R 62 Specific examples of different acid anhydrides.

[0428] As R 61 R 62 You can consider the examples listed above, as well as all combinations of their analogues. The following are representative examples.

[0429] Examples of combinations of chain alkyl groups include acetic propionic anhydride, acetic butyric anhydride, butyric propionic anhydride, and acetic-2-methylpropionic anhydride.

[0430] Examples of combinations of chain alkyl and cyclic alkyl groups include cyclopentanoic acid anhydride, cyclohexanoic acid anhydride, and cyclopentanoic acid propionic anhydride.

[0431] Examples of combinations of chain alkyl and alkenyl groups include acetic acid acrylic anhydride, acetic acid-3-methylacrylic anhydride, acetic acid-3-butenoic anhydride, and acrylate propionic anhydride.

[0432] Examples of combinations of chain alkyl groups and alkynyl groups include acetic propynyl anhydride, acetic-2-butynyl anhydride, acetic-3-butynyl anhydride, acetic-3-phenylpropynyl anhydride, propynyl propionate, etc.

[0433] Examples of combinations of chain alkyl groups and aryl groups include benzoic anhydride, 4-methylbenzoic anhydride, 1-naphthoic anhydride, and propionic anhydride.

[0434] 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.

[0435] Examples of cyclic alkyl groups combined together include cyclopentanoic acid and cyclohexanoic anhydride.

[0436] Examples of combinations of cyclic alkyl and alkenyl groups include cyclopentanolic anhydride of acrylic acid, cyclopentanolic anhydride of 3-methacrylic acid, cyclopentanolic anhydride of 3-butenoic acid, and cyclohexanoic anhydride of acrylic acid.

[0437] Examples of combinations of cyclic alkyl groups and alkynyl groups include propynic acid cyclopentanoic anhydride, 2-butynic acid cyclopentanoic anhydride, propynic acid cyclohexanoic anhydride, etc.

[0438] Examples of combinations of cyclic alkyl and aryl groups include cyclopentanoic anhydride benzoate, 4-methylcyclopentanoic anhydride benzoate, and cyclohexanoic anhydride benzoate.

[0439] Examples of combinations of cyclic alkyl groups with functional hydrocarbon groups include cyclopentanoic anhydride fluoroacetic acid, trifluoroacetic anhydride cyclopentanoic acid, 2-cyanoacetic anhydride cyclopentanoic acid, methoxyacetic anhydride cyclopentanoic acid, and fluoroacetic anhydride cyclohexanoic acid.

[0440] Examples of alkenyl groups combining with each other include 2-methacrylic anhydride, 3-methacrylic anhydride, 3-butenoic anhydride, and 2-methacrylic anhydride-3-methacrylic anhydride.

[0441] 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.

[0442] Examples of combinations of alkenyl and aryl groups include benzoic anhydride acrylic acid, 4-methylbenzoic anhydride acrylic acid, and 2-methacrylic anhydride acrylic acid.

[0443] 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.

[0444] Examples of alkynyl groups combining with each other include propynic acid-2-butynic anhydride, propynic acid-3-butynic anhydride, and 2-butynic acid-3-butynic anhydride.

[0445] Examples of combinations of alkynyl and aryl groups include benzoic acid propargyl anhydride, 4-methylbenzoic acid propargyl anhydride, and benzoic acid-2-butargyl anhydride.

[0446] Examples of combinations of an alkyne group with a hydrocarbon group having 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.

[0447] Examples of aryl groups combining with each other include benzoic acid-4-methylbenzoic anhydride, benzoic acid-1-naphthoic anhydride, and 4-methylbenzoic acid-1-naphthoic anhydride.

[0448] Examples of combinations of aryl groups with functional hydrocarbon groups include fluoroacetic anhydride benzoate, trifluoroacetic anhydride benzoate, 2-cyanoacetic anhydride benzoate, methoxyacetic anhydride benzoate, and fluoroacetic anhydride 4-methylbenzoate.

[0449] 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.

[0450] Among the aforementioned anhydrides that form chain structures, 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; further preferred are 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, etc.

[0451] These compounds form durable films by appropriately forming bonds with lithium oxalate salts, and particularly easily improve charge / discharge rate characteristics, input / output characteristics, and impedance characteristics after durability testing. From this point of view, these compounds are preferred.

[0452] 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 on the other hand, typically 300 or less, preferably 200 or less. When the molecular weight of the carboxylic anhydride is within the above range, the increase in electrolyte viscosity can be suppressed, and since the film density is optimized, durability can be appropriately improved.

[0453] 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 combined in any combination and ratio.

[0454] Furthermore, there are no particular limitations on the content of the aforementioned carboxylic anhydride relative to the electrolyte of the present invention; it can be arbitrary as long as it does not significantly impair the effects of the present invention. The concentration relative to the electrolyte of the present invention is typically 0.01% by mass or more, preferably 0.1% by mass or more, and typically 5% by mass or less, preferably 3% by mass or less. When the content of carboxylic anhydride is within the above range, it easily exhibits an improvement in cycle characteristics, and due to appropriate reactivity, it easily improves battery characteristics.

[0455] In the electrolyte of the present invention, other known additives can be used. Examples of other additives include: Hydrocarbon compounds such as pentane, heptane, octane, nonane, decane, cycloheptane, benzene, furan, naphthalene, 2-phenylbicyclohexane, cyclohexane, 2,4,8,10-tetraoxazolo[5.5]undecane, and 3,9-divinyl-2,4,8,10-tetraoxazolo[5.5]undecane; Fluorobenzene, difluorobenzene, hexafluorobenzene, trifluorotoluene, monofluorobenzene, 1-fluoro-2-cyclohexylbenzene, 1-fluoro-4-tert-butylbenzene, 1-fluoro-3-cyclohexylbenzene, 1-fluoro-2-cyclohexylbenzene, fluorobiphenyls and other fluorinated aromatic compounds. Erythritan Carbonate, spirobis-dimethylene carbonate, methoxyethyl-methyl carbonate and other carbonate compounds; Ether compounds such as dioxolane, dioxane, 2,5,8,11-tetraoxadodecane, 2,5,8,11,14-pentapentadecane, ethoxymethoxyethane, trimethoxymethane, ethylene glycol dimethyl ether, and ethyl monoethylene glycol dimethyl ether. Ketones such as dimethyl ketone, diethyl ketone, and 3-pentanone; 2-Allylsuccinic anhydride and other acid anhydrides; Ester compounds such as dimethyl oxalate, diethyl oxalate, methyl ethyl oxalate, di(2-propynyl) oxalate, methyl-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. Acetamide compounds such as acetamide, N-methylformamide, N,N-dimethylformamide, and N,N-dimethylacetamide; 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, propane disulfonic anhydride, sulfonylbutyric anhydride, sulfonylbenzoic anhydride, sulfonylpropionic anhydride, ethane disulfonic anhydride, methane disulfonic acid methylene ester, methanesulfonic acid-2-propargyl ester, pentylenite sulfite, pentafluorophenyl methanesulfonate, propylene sulfate, propylene sulfite, propanesulfonyl lactone, butene sulfite, butane -2,3-Dimethyl dimethanesulfonate, 2-Butyn-1,4-Dimethyl dimethanesulfonate, Vinylsulfonic acid-2-propynyl ester, 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, trimethylene methane disulfonate, 2-methyltetrahydrofuran, trimethylene methane disulfonate, tetramethylene sulfoxide, dimethylene methane disulfonate, difluoroethylmethyl sulfone, divinyl sulfone, 1,2-bis(vinylsulfonyl)ethane, methyl ethyl ethylene disulfonate, ethyl ethylene disulfonate, ethylene sulfate, thiophene-1-oxide, and other sulfur-containing compounds. Nitrogen-containing compounds such as 1-methyl-2-pyrrolidone, 1-methyl-2-piperidinone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolium, N-methylsuccinimide, nitromethane, nitrobenzene, and ethylenediamine; Trimethyl phosphite, triethyl phosphite, triphenyl phosphite, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dimethyl methylphosphonate, diethyl ethylphosphonate, dimethyl vinylphosphonate, diethyl vinylphosphonate, ethyl diethylphosphonoacetate, methyl dimethylphosphinium hydroxide, ethyl diethylphosphinium hydroxide, 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, tris(2,2,2-trifluoroethyl) phosphate, tris(1,1,1,3,3,3-hexafluoropropane-2-yl) phosphate, trioctyl phosphate, 2-phenylphenyl dimethyl phosphate, 2-phenylphenyl diethyl phosphate, 2, 2,2-Trifluoroethyl)(2,2,3,3-Tetrafluoropropyl)methyl ester, 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 butyl bisphosphonate, methyl butyl bisphosphonate, ethyl butyl bisphosphonate, 2-propynyl-2-(dimethoxyphosphoryl)acetate Phosphorus-containing compounds such as 2-propynyl-2-(dimethylphosphoryl) acetate, 2-propynyl-2-(diethoxyphosphoryl) acetate, 2-propynyl-2-(diethylphosphoryl) acetate, tri(trimethylsilyl) phosphate, tri(triethylsilyl) phosphate, tri(trimethoxysilyl) phosphate, tri(trimethylsilyl) phosphite, tri(triethylsilyl) phosphite, tri(trimethoxysilyl) phosphite, and trimethylsilyl polyphosphate; Boron-containing compounds such as tris(trimethylsilyl) borate and tris(trimethoxysilyl) borate; Silane compounds such as dimethylammonium trimethylaluminum silicate, diethanoltriethylaluminum silicate, dipropanoltriethylaluminum silicate, dibutanoltrimethylaluminum silicate, dibutanoltriethylaluminum silicate, tetra(trimethylsiloxy)titanium, tetra(triethylsiloxy)titanium, and tetramethylsilane; etc.

[0456] They can be used individually or in combination of two or more. By adding these additives, it is easy to improve the capacity retention and cycling characteristics after high-temperature storage.

[0457] As other adjuvants mentioned above, phosphorus-containing compounds are preferred, and tris(trimethylsilyl) phosphate and tris(trimethylsilyl) phosphite are particularly preferred.

[0458] 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 more preferably 5% by mass or less. Within this range, it is easy to fully exhibit the effects of the other additives, 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; and more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0459] The electrolyte of the present invention may also 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, within a range that does not impair the effects of the present invention.

[0460] 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 from the viewpoint of improving the characteristics of electrochemical devices due to increased lithium-ion dissociation.

[0461] The amount of the cyclic carboxylic acid ester used as an additive is preferably 0.1% by mass or more, and more preferably 1% by mass or more, in 100% by mass of the solvent. Within this range, it is easy to improve the conductivity of the electrolyte and 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, and more preferably 5% by mass or less. By setting such an upper limit, it is easy to achieve a suitable viscosity range for the electrolyte, avoid a decrease in conductivity, suppress an increase in negative electrode resistance, and easily achieve a good range of high-current discharge characteristics for the electrochemical device.

[0462] In addition, fluorocyclic carboxylic acid esters (fluorinated lactones) are also suitable as the aforementioned cyclic carboxylic acid esters. Examples of fluorinated lactones include those shown in formula (C). (where X) 15 ~X 20 Whether identical or different, all are -H, -F, -Cl, -CH3, or fluoroalkyl; among which, X 15 ~X 20 At least one of them represents a fluoroalkyl group. As X 15 ~X 20Fluorinated alkyl groups can be exemplified by, for example, -CFH2, -CF2H, -CF3, -CH2CF3, -CF2CF3, -CH2CF2CF3, -CF(CF3)2, etc. From the viewpoint of high oxidation resistance and improved safety, -CH2CF3 and -CH2CF2CF3 are preferred.

[0463] X 15 ~X 20 When at least one of them is a fluoroalkyl group, -H, -F, -Cl, -CH3, or a fluoroalkyl group can be used only in X. 15 ~X 20 One substitution may be made at one location, or multiple substitutions may be made. From the viewpoint of good solubility of electrolyte salts, one to three substitutions are preferred, and one to two substitutions are more preferred.

[0464] The substitution position of the fluoroalkyl group is not particularly limited; from the viewpoint of good synthetic yield, X is preferred. 17 and / or X 18 Especially X 17 or X 18 It is a fluoroalkyl group, preferably -CH2CF3 or -CH2CF2CF3. X other than a fluoroalkyl group 15 ~X 20 The form can be -H, -F, -Cl, or CH3, with -H being particularly preferred from the viewpoint of good solubility of electrolyte salts.

[0465] In addition to the substances shown in the above formula, other examples of fluorinated lactones, such as those shown in formula (D), can also be listed as fluorinated lactones. (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 alkylene groups (where the hydrogen atom can be replaced by a halogen atom and the chain can contain heteroatoms), and 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 two are the same or different, they are all -H, -F, -Cl, -CF3 or CH3; X 223 ~X 225 Whether identical or different, all are alkyl groups in which -H, -F, -Cl, or hydrogen atoms can be replaced by halogen atoms, and the chain may contain heteroatoms; n = 0 or 1. From the viewpoints of ease of synthesis and good chemical stability, the 5-membered ring structure shown in formula (E) is preferred as the fluorinated lactone represented by formula (D). (In the formula, A, B, Rf) 12 X 221 X 222 and X 223 Same as equation (D). Furthermore, through the combination of A and B, there are fluorinated lactones as shown in formula (F) and fluorinated lactones as shown in formula (G). (where Rf) 12 X 221 X 222 X 223 X 226 and X 227 Same as equation (D). (where Rf) 12 X 221 X 222 X 223 X 226 and X 227 Same as equation (D). Among these, from the perspectives of particularly exhibiting excellent properties such as high dielectric constant and high voltage resistance, as well as the viewpoints of good solubility of electrolyte salt and reduction of internal resistance, and the viewpoints of improved properties of the electrolyte of the present invention, the following can be listed: wait.

[0466] By using fluorinated cyclic carboxylic esters, it is easy to obtain effects such as improved ionic conductivity, enhanced safety, and improved stability at high temperatures.

[0467] As examples of the aforementioned chain-like carboxylic acid esters, substances with a total carbon number of 3 to 7 in their structural formulas can be listed. 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.

[0468] From the viewpoint of improving ionic conductivity by reducing 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.

[0469] As the above-mentioned ether compounds, chain ethers with 2 to 10 carbon atoms and cyclic ethers with 3 to 6 carbon atoms are preferred.

[0470] 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.

[0471] In addition, fluoroethers are also suitable as the aforementioned ether compounds.

[0472] As examples of the aforementioned fluoroethers, fluoroethers represented by the following general formula (I) can be listed (I).

[0473] Rf 3 -O-Rf 4 (I) (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.) By containing fluorinated ethers (I), the flame retardancy of the electrolyte can be easily improved, as well as its stability and safety under high temperature and high voltage.

[0474] In the above general formula (I), Rf 3 and Rf 4 At least one of them can be a fluoroalkyl group having 1 to 10 carbon atoms, but from the viewpoint 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 All are fluoroalkyl groups with 1 to 10 carbon atoms. At this point, Rf 3 and Rf 4 They can be the same, or they can be different from each other.

[0475] Among these, from the perspectives of optimizing the boiling point of fluoroethers, and also improving the solubility of electrolyte salts and compatibility with other solvents, Rf 3 and Rf 4 Same or different, Rf is preferred 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.

[0476] Rf 3 and Rf 4 When the total number of carbon atoms is too low, the boiling point of fluoroethers becomes too low; while Rf3 or Rf 4 When the number of carbon atoms is too high, the solubility of the electrolyte salt decreases, its compatibility with other solvents begins to be adversely affected, and its rate performance decreases due to increased viscosity. 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.

[0477] The fluorine content of the aforementioned fluorinated ether (I) is preferably 40–75% by mass. At fluorine contents within this range, the balance between non-flammability and compatibility is particularly excellent. Furthermore, it is also preferred from the viewpoint of good oxidation resistance and safety.

[0478] The lower limit of the aforementioned 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.

[0479] The fluorine content of fluorinated ether (I) is calculated based on the structural formula of fluorinated ether (I) by using {(number of fluorine atoms × 19) / molecular weight of fluorinated ether (I)} × 100 (mass%).

[0480] As Rf 3 Examples include CF3CF2CH2-, CF3CFHCF2-, HCF2CF2CF2-, HCF2CF2CH2-, CF3CF2CH2CH2-, CF3CFHCF2CH2-, HCF2CF2CF2CF2-, HCF2CF2CF2CH2-, HCF2CF2CH2CH2-, HCF2CF(CF3)CH2-, etc. Additionally, as Rf 4 Examples of such combinations include -CH2CF2CF3, -CF2CFHCF3, -CF2CF2CF2H, -CH2CF2CF2H, -CH2CH2CF2CF3, -CH2CF2CFHCF3, -CF2CF2CF2CF2H, -CH2CF2CF2CF2H, -CH2CH2CF2CF2H, -CH2CF(CF3)CF2H, -CF2CF2H, -CH2CF2H, -CF2CH3, etc.

[0481] Specific examples of the aforementioned fluorinated ethers (I) include, for example, HCF2CF2CH2OCF2CF2H, CF3CF2CH2OCF2CF2H, HCF2CF2CH2OCF2CFH, CF3, CF3CF2CH2OCF2CFHCF3, and C6F. 13 OCH3, C6F 13 OC2H5, C8F 17OCH3, C8F 17 OC2H5, CF3CFHCF2CH (CH3) OCF2CFHCF3, HCF2CF2OCH (C2H5) 2, HCF2CF2OC4H9, HCF2CF2OCH2CH (C2H5) 2, HCF2CF2OCH2CH (CH3) 2, etc.

[0482] Among them, substances with HCF2− or CF3CFH− at one or both ends have excellent polarizability and can produce fluorinated ethers (I) with high boiling points. The boiling point of fluorinated ethers (I) is preferably 67–120°C. More preferably, it is 80°C or higher, and even more preferably, it is 90°C or higher.

[0483] Examples of such fluorinated ethers (I) include one or more of the following: CF3CH2OCF2CFHCF3, CF3CF2CH2OCF2CFHCF3, HCF2CF2CH2OCF2CFHCF3, HCF2CF2CH2O CH2CF2CF2H, CF3CFHCF2CH2OCF2CFHCF3, HCF2CF2CH2OCF2CF2H, and CF3CF2CH2OCF2CF2H.

[0484] From the viewpoints of high boiling point, compatibility with other solvents, and good solubility of electrolyte salts, it is preferred 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).

[0485] 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, trioxane, 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. From the viewpoint of high solvation ability 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 ethers are preferred. From the viewpoint of low viscosity and the ability to impart high ionic conductivity, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are particularly preferred.

[0486] 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-imidazolinone, and N-methylsuccinimide may also be used. However, the nitrogen-containing compounds mentioned above do not include nitrile compounds represented by the general formulas (1a), (1b), and (1c).

[0487] Examples of boron-containing compounds mentioned above include borate esters such as trimethyl borate and triethyl borate, borate ethers, and alkyl borate esters.

[0488] Examples of the aforementioned organosilicon compounds include (CH3)4-Si, (CH3)3-Si-Si(CH3)3, and silicone oil.

[0489] Examples of non-flammable (flame retardant) agents include phosphate esters and phosphazene compounds. Examples of phosphate esters include, for example, fluorinated alkyl phosphate esters, non-fluorinated alkyl phosphate esters, and aryl phosphate esters. Among these, fluorinated alkyl phosphate esters are preferred from the viewpoint that they can exert a non-flammable effect with a small amount.

[0490] Examples of the aforementioned phosphazene compounds include methoxypentafluorocyclotriphosphazene, phenoxypentafluorocyclotriphosphazene, dimethylaminopentafluorocyclotriphosphazene, diethylaminopentafluorocyclotriphosphazene, ethoxypentafluorocyclotriphosphazene, and ethoxyheptafluorocyclotetraphosphazene.

[0491] 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 the fluorinated trialkyl phosphates.

[0492] As the aforementioned non-flammable (flame retardant) agents, (CH3O)3P=O, (CF3CH2O)3P=O, (HCF2CH2O)3P=O, (CF3CF2CH2)3P=O, (HCF2CF2CH2)3P=O, etc. are preferred.

[0493] The surfactants mentioned above can be any type of cationic surfactant, anionic surfactant, nonionic surfactant, or amphoteric surfactant. From the viewpoint of good cycling characteristics and rate capability, surfactants containing fluorine atoms are preferred.

[0494] As such surfactants containing fluorine atoms, fluorinated carboxylates as shown in formula (30) and fluorinated sulfonates as shown in formula (40) are preferred.

[0495] Rf 5 COO － M ＋ (30) (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, both are H or alkyl groups with 1 to 3 carbon atoms). Rf 6 SO3 － M ＋ (40) (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, both are H or alkyl groups with 1 to 3 carbon atoms). Regarding the content of the surfactant, from the viewpoint that it is easy to reduce the surface tension of the electrolyte without reducing the charge-discharge cycle characteristics, it is preferably 0.01 to 2% by mass in the electrolyte.

[0496] Examples of additives that can be used to increase the dielectric constant include sulfolane, methylsulfolane, γ-butyrolactone, and γ-valerolactone.

[0497] Examples of agents that can improve the aforementioned cycling and rate characteristics include methyl acetate, ethyl acetate, tetrahydrofuran, and 1,4-dioxane.

[0498] In addition, the electrolyte of the present invention can be further combined with polymer materials to form a gel-like (plasticized) gel electrolyte.

[0499] Examples of such polymeric materials include existing known polyoxyethylene or polyoxypropylene, their modified forms (Japanese Patent Application Publication No. 8-222270, Japanese Patent Application Publication No. 2002-100405); fluoropolymers such as polyacrylate polymers, polyacrylonitrile or polyvinylidene fluoride, and polyvinylidene 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 composites of these fluoropolymers with hydrocarbon resins (Japanese Patent Application Publication No. 11-35765, Japanese Patent Application Publication No. 11-86630). It is particularly desirable to use polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymers as polymeric materials for gel electrolytes.

[0500] Furthermore, the electrolyte of the present invention may also contain an ion-conducting compound as described in Japanese Patent Application No. 2004-301934.

[0501] The ion-conducting compound is an amorphous fluorinated polyether compound with fluorinated groups on the side chain, as shown in formula (101).

[0502] A-(D)-B(101) [In the formula, D represents formula (201).] - (D1) n - (FAE) m - (AE) p (Y) q - (201) (In the formula, D1 is the ether unit with a fluorinated ether group in the side chain as shown in formula (2a),) (In the formula, Rf represents a fluorinated ether group that can have crosslinking functional groups; R 10 (This refers to the group or valence bond that binds Rf to the main chain.) FAE is an ether unit with a fluoroalkyl side chain as shown in formula (2b). (In the formula, Rfa represents a hydrogen atom and a fluoroalkyl group that can have cross-linking functional groups; R 11 This refers to the group or valence bond that binds Rfa to the main chain. AE is the ether unit shown in formula (2c). (where R) 13 Represents 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 Indicates that R 13(Groups or valence bonds that are bonded to the main chain.) Y is a unit containing at least one of the formulas (2d-1) to (2d-3). ; 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 combination order of D1, FAE, AE, and Y is not specific). A and B may be the same or different, and can be a hydrogen atom, an alkyl group that may contain a fluorine atom and / or a cross-linking functional group, a phenyl group that may contain a fluorine atom and / or a cross-linking functional group, a -COOH group, a -OR group (where R is a hydrogen atom or an alkyl group that may contain a fluorine atom and / or a cross-linking functional group), an ester group, or a carbonate group (wherein, when the terminal of D is an oxygen atom, it is not a -COOH group, -OR group, ester group, or carbonate group). 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.

[0503] Examples of cyclic sulfones include: trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones as monosulfone compounds; and trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones as disulfone compounds. From the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, and hexamethylene sulfones are further preferred, with tetramethylene sulfones (sulfolane) being particularly preferred.

[0504] As sulfolane derivatives, sulfolane and / or sulfolane derivatives are preferred (hereinafter, sometimes including sulfolane, they are simply referred to as "sulfolane derivatives"). As sulfolane derivatives, 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.

[0505] From the perspective of high ionic conductivity and high input / output efficiency, the preferred ions are 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.

[0506] 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.

[0507] 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.

[0508] The content of sulfone compounds is not particularly limited, and any value is acceptable as long as it does not significantly impair the effects of the present invention. In the above-mentioned solvent 100% by volume, it is typically 0.3% by volume or more, preferably 0.5% by volume or more, more preferably 1% by volume or more, and typically 40% by volume or less, preferably 35% by volume or less, more preferably 30% by volume or less. When the content of sulfone compounds is within the above range, it is easy to obtain effects such as improved cycle characteristics and storage characteristics, thus enhancing durability. Furthermore, it allows the viscosity of the non-aqueous electrolyte to be within an appropriate range, preventing a decrease in conductivity, and enabling the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery to be within an appropriate range.

[0509] From the viewpoint of improving output characteristics, the electrolyte of the present invention preferably contains, as an additive, at least one compound selected from lithium fluorophosphates (excluding LiPF6) and lithium salts having an S=O group.

[0510] In the case of using this compound as an additive, it is preferable to use a compound other than this compound as the electrolyte salt mentioned above.

[0511] Examples of lithium fluorophosphate salts include lithium monofluorophosphate (LiPO3F) and lithium difluorophosphate (LiPO2F2).

[0512] Examples of lithium salts with the S=O group include lithium monofluorosulfonate (FSO3Li), lithium methyl sulfate (CH3OSO3Li), lithium ethyl sulfate (C2H5OSO3Li), and 2,2,2-trifluoroethyl lithium sulfate.

[0513] LiPO2F2, FSO3Li, and C2H5OSO3Li are preferred compounds.

[0514] From the viewpoint of the performance of electrochemical devices, the content of the compound 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.

[0515] The electrolyte of this invention can be further formulated with other additives as needed. Examples of other additives include metal oxides and glass.

[0516] The preferred hydrogen fluoride (HF) content in the electrolyte of the present invention is 5 to 200 ppm. The presence of HF facilitates the formation of a film on the aforementioned additives. When the HF content is too low, the ability to form a film on the negative electrode decreases, leading to a tendency for a decline in the characteristics of the electrochemical device. Furthermore, when 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 capacity recovery rate of the electrochemical device.

[0517] 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.

[0518] The content of HF can be determined by neutralization titration.

[0519] The electrolyte of the present invention can be prepared using the above-mentioned components by any method.

[0520] The electrolyte of the present invention is suitable for use in 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.

[0521] The aforementioned non-aqueous electrolyte battery can employ a known structure, typically including a positive electrode and a positive electrode capable of adsorbing and releasing ions (e.g., lithium ions), and the electrolyte of the present invention described above. Electrochemical devices incorporating such an electrolyte of the present invention are also part of this invention.

[0522] 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, and tantalum electrolytic capacitors. Lithium-ion secondary batteries, lithium-ion capacitors, and double-layer capacitors are preferred.

[0523] A module equipped with the aforementioned electrochemical devices is also one of the inventions.

[0524] The present invention also relates to lithium-ion secondary batteries having the electrolyte of the present invention.

[0525] The aforementioned lithium-ion secondary battery preferably includes a positive electrode, a negative electrode, and the aforementioned electrolyte.

[0526] <Positive electrode> The positive electrode can be composed of a layer of positive electrode active material containing positive electrode active material and a current collector.

[0527] As for the aforementioned positive electrode active material, there are no particular restrictions as long as it can electrochemically retain and release lithium ions. Examples include lithium-containing transition metal composite oxides, lithium-containing transition metal phosphate compounds, sulfides (chalcogenide materials), 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 generate high voltage are particularly preferred.

[0528] Transition metals preferred for lithium-containing transition metal composite oxides include V, Ti, Cr, Mn, Fe, Co, Ni, and Cu. 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. Compounds formed by replacing a portion of the main transition metal atom in 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 compounds formed by substitution include LiNi... 0.5 Mn 0.5 O2, LiNi 0.85 Co 0.10 Al 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.

[0529] Among these, LiMn, which has a high energy density even at high voltages, is preferred as the aforementioned lithium-containing transition metal composite oxide. 1.5 Ni 0.5 O4, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2O2. Among these, LiMn is preferred at high voltages above 4.4V. 1.5 Ni 0.5 O4.

[0530] The preferred transition metals for lithium transition metal phosphate compounds are V, Ti, Cr, Mn, Fe, Co, Ni, and Cu. Specific examples include iron phosphates such as LiFePO4, Li3Fe2(PO4)3, and LiFeP2O7; cobalt phosphates such as LiCoPO4; and compounds formed by replacing a portion of the main transition metal atom in 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, and Si.

[0531] Examples of lithium-containing transition metal composite oxides mentioned above include: Formula: Li a Mn 2－b M 1 b O4 (where 0.9≤a; 0≤b≤1.5; M) 1 The lithium manganese spinel composite oxide is 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. Formula: LiNi 1－c M 2 c O2 (where 0 ≤ c ≤ 0.5; M) 2 A lithium-nickel composite oxide (or) selected from at least one metal chosen from Fe, Co, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge) Formula: LiCo 1－d M 3 d O2 (where 0 ≤ d ≤ 0.5; M) 3 The lithium cobalt composite oxide is selected from at least one metal chosen from Fe, Ni, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si and Ge.

[0532] 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 Co1／3 Mn 1／3 O2.

[0533] Other examples of the aforementioned positive electrode active materials 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, Li2MnO3, etc.

[0534] Examples of sulfur-based materials include those containing sulfur atoms, preferably selected from at least one of elemental sulfur, metal sulfides, and organosulfur compounds, more preferably elemental sulfur. The metal sulfides may be metal polysulfides. The organosulfur compounds may be organopolysulfides.

[0535] Examples of the aforementioned metal sulfides include: LiS x The compound shown is (0 < x ≤ 8); Li2S x Compounds with the formula (0 < x ≤ 8); compounds with two-dimensional layered structures such as TiS2 and MoS2; compounds with the general formula Me x Chevrel compounds, such as Mo6S8 (where Me represents various transition metals such as Pb, Ag, and Cu), have a robust three-dimensional framework structure.

[0536] Examples of the aforementioned organosulfur compounds include carbon sulfide compounds.

[0537] The aforementioned organosulfur compounds are sometimes supported on microporous materials such as carbon and used as carbon composite materials. From the viewpoint of superior cycling performance and further reduction of overpotential, the sulfur content in the carbon composite material is preferably 10 to 99% by mass, more preferably 20% by mass or more, even more preferably 30% by mass or more, particularly preferably 40% by mass or more, and most preferably 85% by mass or less.

[0538] When the above-mentioned positive electrode active material is the above-mentioned elemental sulfur, the sulfur content contained in the above-mentioned positive electrode active material is equal to the content of the above-mentioned elemental sulfur.

[0539] Examples of conductive polymers include p-doped and n-doped conductive polymers. Examples of conductive polymers include polyacetylene-based polymers, polyphenylene-based polymers, heterocyclic polymers, ionic polymers, ladder-like polymers, and network polymers.

[0540] Furthermore, the presence of lithium phosphate in the positive electrode active material improves continuous charging characteristics, making it preferable. 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, and even more preferably 0.5% by mass or more; 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.

[0541] Furthermore, active materials with a different composition can be used on the surface of the aforementioned positive electrode active material. Examples of surface-attached materials 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.

[0542] 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, impregnating them into the positive electrode active material, and then drying them; dissolving or suspending the surface-adhesive substance precursor in a solvent, impregnating it into the positive electrode active material, and then reacting it by heating or the like; adding it to the positive electrode active material precursor while simultaneously calcining it, etc. Additionally, in the case of carbon attachment, a method can be used to mechanically attach carbonaceous material, such as activated carbon.

[0543] The amount of surface-attached material, relative to the mass of the aforementioned positive electrode active material, is preferably 0.1 ppm or more, more preferably 1 ppm or more, and even more preferably 10 ppm or more, as a lower limit; and preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less, as an upper limit. 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, this effect is not fully realized, while if the amount is too large, it may sometimes hinder the movement of lithium ions, thus increasing the resistance.

[0544] The shapes of positive electrode active material particles can include currently used blocky, polyhedral, spherical, ellipsoidal, plate-like, needle-like, and columnar shapes. Furthermore, primary particles can aggregate to form secondary particles.

[0545] The tap density of the positive electrode active material is preferably 0.5 g / cm³. 3 The above, more preferably 0.8 g / cm³ 3 The above is further preferred to be 1.0 g / cm³. 3The above applies. When the tap density of the positive electrode active material is lower than the aforementioned lower limit, the amount of dispersion medium required to form the positive electrode active material layer increases, and the amount of conductive material and binder required also increases. Sometimes, the filling rate of the positive electrode active material in the positive electrode active material layer is limited, thus limiting the battery capacity. By using composite oxide powder with high tap density, a high-density positive electrode active material layer can be formed. Generally, the higher the tap density, the better, and there is no particular upper limit. However, if it is too high, sometimes the diffusion of lithium ions using the electrolyte as a medium within the positive electrode active material layer becomes the rate-determining step, and the loading characteristics are easily reduced. 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.

[0546] In this invention, the tap density is defined as the powder filling density (tap density) in g / cm³ when 5-10g of the positive electrode active material powder is placed into a 10ml glass graduated cylinder and tapped 200 times at an amplitude of approximately 20mm. 3 Find the answer.

[0547] The median diameter d50 (secondary particle size when primary particles aggregate to form secondary particles) of the positive electrode active material particles 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; and preferably 30 μm or less, more preferably 27 μm or less, further preferably 25 μm or less, and most preferably 22 μm or less. Below the above lower limits, products with high tap density are sometimes not obtained. Above the upper limit, due to the time required for lithium diffusion within the particles, battery performance may be reduced, or problems such as pull-out streaks may occur during the fabrication of the positive electrode, i.e., when the active material, conductive material, and binder are slurried together using a solvent and coated into a thin film. Here, the filling properties during positive electrode fabrication can be further improved by mixing two or more of the above-mentioned positive electrode active materials with different median diameters d50.

[0548] In this invention, the median diameter d50 is measured using a known laser diffraction / scattering particle size distribution measuring device. When using a HORIBA LA-920 particle size analyzer, 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.

[0549] 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, and even more preferably 0.2 μm or more; the upper limit is 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. Above the above upper limit, it is difficult to form spherical secondary particles, which adversely affects powder filling properties or significantly reduces the specific surface area, thus increasing the possibility of decreased battery performance such as output characteristics. Conversely, below the above lower limit, crystal growth is usually not achieved, which may sometimes lead to problems such as poor reversibility of charge and discharge.

[0550] In this invention, the primary particle size can be determined by observation using a scanning electron microscope (SEM). Specifically, in a 10,000x magnification photograph, for any 50 primary particles, the longest value of the slice formed by the left and right boundary lines of the primary particles relative to a straight line in the horizontal direction is taken, and the average value is calculated.

[0551] 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; the upper limit is preferably 50m 2 / g or less, preferably 40m 2 / g or less, more preferably 30m 2 Below / g. When the BET specific surface area is less than this range, the battery performance is prone to decline, while when it is greater than this range, it is difficult to increase the tap density, and sometimes the coating properties when forming the positive electrode active material layer are prone to problems.

[0552] In addition, in this invention, the BET specific surface area is defined as the value measured by the following method: using a surface area meter (e.g., Ohkura Riken Co. Ltd., which manufactures fully automated surface area measuring devices), after pre-drying the sample at 150°C for 30 minutes under nitrogen flow, a nitrogen-helium mixed gas with the relative pressure of nitrogen to atmospheric pressure accurately adjusted to 0.3 is used to determine the BET 1-point method based on gas flow.

[0553] In the case where 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 above-mentioned positive electrode active material are preferably mainly secondary particles.

[0554] The positive electrode active material particles preferably contain 0.5 to 7.0% by volume of secondary particles with an average particle size of less than 40 μm and an average primary particle size of less than 1 μm. By containing particles with an average primary particle size of less than 1 μm, the contact area with the electrolyte is increased, which further accelerates the diffusion of lithium ions between the electrode and the electrolyte, thereby improving the output performance of the battery.

[0555] The method for manufacturing positive electrode active materials can employ conventional methods used for manufacturing inorganic compounds. Especially when preparing spherical or ellipsoidal active materials, various methods can be considered, such as the following: dissolving or dispersing the transition metal raw material in a solvent such as water, adjusting the pH while stirring, forming a spherical precursor and recovering it, drying it as needed, adding a Li source such as LiOH, Li₂CO₃, or LiNO₃, and calcining at high temperature to obtain the active material.

[0556] To manufacture the positive electrode, the aforementioned positive electrode active material can be used alone, or two or more different components can be combined in any combination or proportion. As a preferred combination in this case, LiCoO2 and LiNi can be cited as examples. 0.33 Co 0.33 Mn 0.33 Combinations of substances formed by replacing LiMn2O4 or a portion of its Mn with other transition metals, such as O2, or combinations of substances formed by replacing LiCoO2 or a portion of its Co with other transition metals.

[0557] 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. Moreover, the upper limit is preferably 99% by mass or less, more preferably 98% by mass or less. When the content of the positive electrode active material in the positive electrode active material layer is low, the electrical capacity may sometimes be insufficient. Conversely, when the content is too high, the strength of the positive electrode may sometimes be insufficient.

[0558] The aforementioned positive electrode mixture preferably further contains a binder, a thickener, and a conductive material.

[0559] As the aforementioned binder, any material safe for the solvents and electrolytes used in the manufacture of the electrodes can be used. Examples include: resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamides, 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 intercalation polymers. Block copolymers or their hydrides; thermoplastic elastomers such as EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-styrene copolymer, and 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 combination or proportion of two or more in any way.

[0560] Regarding the binder content, based on the proportion of binder in the positive electrode active material layer, it 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. When the binder proportion is too low, the positive electrode active material may not be sufficiently retained, resulting in insufficient mechanical strength of the positive electrode and deterioration of battery performance such as cycle characteristics. Conversely, when the proportion is too high, it may sometimes lead to a decrease in battery capacity or conductivity.

[0561] Examples of thickeners mentioned above include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, polyvinylpyrrolidone, and their salts. One type can be used alone, or two or more can be used in any combination and proportion.

[0562] 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. Below this range, the coatability may sometimes decrease significantly. Above this range, the proportion of active material in the positive electrode active material layer decreases, sometimes resulting in reduced battery capacity or increased resistance between positive electrode active materials.

[0563] 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, etc. Each of these materials can be used individually or in any combination and proportion. The conductive material is typically used in the positive electrode active material layer at a content of 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, and typically 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less. When the content is below this range, conductivity may become insufficient. Conversely, when the content is above this range, battery capacity may decrease.

[0564] 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 and mixtures of alcohol and water. 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.

[0565] Materials that can be used as current collectors for the positive electrode include metals such as aluminum, titanium, tantalum, stainless steel, and nickel, or their alloys; and carbon materials such as carbon cloth and carbon paper. Among these, metal materials are preferred, and aluminum or its alloys are particularly preferred.

[0566] In the case of metallic materials, various shapes of current collectors can be included, such as metal foil, metal cylinder, metal coil, metal plate, metal film, expanded metal, punched metal, and foamed metal. In the case of carbon materials, carbon plates, carbon films, and carbon cylinders can be included. Among these, metal films are preferred. Furthermore, the film can be appropriately shaped 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. When the film is thinner than this range, the strength required for current collection may be insufficient. Conversely, when the film is thicker than this range, operability may be impaired.

[0567] Furthermore, from the viewpoint of reducing the electrical contact resistance between the current collector and the positive electrode active material layer, it is also preferable to coat the surface of the current collector with a conductive additive. Examples of conductive additives include carbon or precious metals such as gold, platinum, and silver.

[0568] The ratio of the current collector thickness to the thickness of the positive electrode active material layer is not particularly limited, but preferably (the thickness of the positive electrode active material layer on one side before electrolyte injection) / (the thickness of the current collector) is 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. Above this range, the current collector may sometimes generate exothermic heat due to Joule heating during high current density charging and discharging. Below this range, the volume ratio of the current collector to the positive electrode active material increases, and sometimes the battery capacity decreases.

[0569] The positive electrode can be manufactured using conventional methods. For example, one method is to add the aforementioned binder, thickener, conductive material, solvent, etc., to the above-mentioned positive electrode active material to form a slurry-like positive electrode mixture, coat it onto the current collector, and then pressurize it after drying to achieve high density.

[0570] The aforementioned high-density processing can be carried out using a hand press, roller press, etc. The preferred density of the positive electrode active material layer is 1.5 g / cm³. 3 The above is preferred, 2g / cm 3 The above is further optimized to 2.2 g / cm³. 3 The above range; and preferably 5g / cm 3 Below, 4.5 g / cm³ is preferred. 3 The following is a further preferred option: 4g / cm 3 The following range applies. Above this range, the permeability of the electrolyte to the interface between the current collector and the active material decreases, especially the charge-discharge characteristics at high current densities, sometimes resulting in a failure to achieve high output. Below this range, the conductivity between the active materials decreases, the battery resistance increases, and sometimes a failure to achieve high output is also observed.

[0571] 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 large relative to the outer surface area of ​​the battery outer 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 outer casing. The outer surface area of ​​the battery outer 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 of ​​the casing portion filled with the power generation element, excluding the terminal protrusions, approximating a cylinder. 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 calculated for each side separately.

[0572] 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 after deducting the thickness of the core metal foil is preferably 10 μm or more, more preferably 20 μm or more, for one side of the current collector; and preferably 500 μm or less, more preferably 450 μm or less.

[0573] Alternatively, a positive electrode plate with a different composition can be used, on the surface of which the aforementioned positive electrode plate is attached. Examples of such surface attachment materials 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.

[0574] <Negative electrode> The negative electrode consists of a layer of negative electrode active material containing negative electrode active material and a current collector.

[0575] As a negative electrode material, there are no particular restrictions as long as it can electrochemically adsorb 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 combined in any way.

[0576] Examples of negative electrode active materials include thermal decomposition products of organic matter under various thermal decomposition conditions, or 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 also be used in combination.

[0577] As a carbonaceous material capable of absorbing and releasing lithium, materials preferably include artificial graphite or refined natural graphite obtained by high-temperature treatment of easily graphitizable pitch from various raw materials, or materials obtained by carbonizing these graphites after surface treatment with pitch or other organic substances. The materials are selected from: carbonaceous materials formed by heat-treating natural graphite, artificial graphite, artificial carbonaceous materials, and artificial graphitic materials at a temperature ranging from 400 to 3200°C once or more; carbonaceous materials in which the negative electrode active material layer is composed of at least two types of carbonaceous materials with different crystallinities and / or has an interface where carbonaceous phases with these different crystallinities are in contact; and carbonaceous materials in which the negative electrode active material layer has an interface where carbonaceous phases with at least two different orientations are in contact. Materials with a good balance between initial irreversible capacity and high current density charge-discharge characteristics are more preferred. Furthermore, these carbon materials can be used individually or in combination or proportion of two or more types in any combination.

[0578] Examples of carbonaceous materials formed by subjecting artificial carbonaceous materials and artificial graphitic materials to heat treatment at a temperature of 400–3200°C or higher include: coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch and substances obtained by oxidizing these pitches, needle coke, pitch coke and carbonizing agents formed by partially graphitizing these, furnace black, acetylene black, pitch-based carbon fibers and other organic thermal decomposition products, carbonizable organic materials and their carbides, or solutions of carbonizable organic materials dissolved in low-molecular-weight organic solvents such as benzene, toluene, xylene, quinoline, n-hexane and their carbides.

[0579] As the metallic material used as the aforementioned negative electrode active material (excluding lithium-titanium composite oxides), it can be any type of elemental lithium, elemental metals forming lithium alloys, alloys, or their oxides, carbides, nitrides, silicides, sulfides, or phosphides, as long as it can adsorb and release lithium, without particular limitation. As the elemental metals and alloys forming lithium alloys, materials containing metals or half-metals of Group 13 and Group 14 are preferred, and elemental metals of aluminum, silicon, and tin (hereinafter referred to as "specific metal elements") and alloys or compounds containing these atoms are more preferred. One type can be used alone, or two or more can be used in any combination and proportion.

[0580] Examples of negative electrode active materials having atoms selected from at least one specific metallic element include: elemental metals of any one specific metallic element; alloys formed from two or more specific metallic elements; alloys formed from one or more specific metallic elements and one or more other metallic elements; compounds containing one or more specific metallic elements; and composite compounds such as oxides, carbides, nitrides, silicides, sulfides, or phosphides of such compounds. By using these elemental metals, alloys, or metallic compounds as negative electrode active materials, high battery capacity can be achieved.

[0581] Furthermore, these composite compounds can also include metallic elements, alloys, or compounds that are complex combinations of multiple elements such as non-metallic elements. Specifically, for example, when using silicon or tin, alloys of these elements with metals that do not function as negative electrodes can be used. For example, in the case of tin, complex compounds containing 5 to 6 elements can be used, such as metals other than tin and silicon that function as negative electrodes, metals that do not function as negative electrodes, and combinations of non-metallic elements.

[0582] Specifically, examples include elemental Si, SiB4, SiB6, Mg2Si, Ni2Si, TiSi2, MoSi2, CoSi2, NiSi2, CaSi2, CrSi2, Cu6Si, FeSi2, MnSi2, NbSi2, TaSi2, VSi2, WSi2, ZnSi2, SiC, Si3N4, Si2N2O, and SiO2. v (0 < v ≤ 2), LiSiO or elemental tin, SnSiO3, LiSnO, Mg2Sn, SnO w (0 < w ≤ 2).

[0583] Additionally, composite materials that use Si or Sn as the first constituent element, and also contain a second and a third constituent element, can be listed. 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.

[0584] In particular, from the viewpoint of achieving high battery capacity and excellent battery characteristics, elemental silicon or tin (which may contain trace impurities) and SiO2 are preferred as the aforementioned metallic materials. 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.

[0585] 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 viewpoint 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, when lithium-titanium composite oxides with spinel structures are used as negative electrode active materials for electrolyte batteries, the output resistance is significantly reduced, and therefore they are particularly preferred.

[0586] As the aforementioned lithium-titanium composite oxide, the preferred general formula is: Li x Ti y M z The compound shown is O4.

[0587] [In the formula, M represents at least one element selected from Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb.] In the above composition, the following condition is met: (i) 1.2≤x≤1.4, 1.5≤y≤1.7, z=0 (ii) 0.9≤x≤1.1, 1.9≤y≤2.1, z=0 (iii) 0.7≤x≤0.9, 2.1≤y≤2.3, z=0 The structure is particularly preferred due to its good balance of battery performance.

[0588] Regarding the particularly preferred representative composition of the above-mentioned compound, in (i) it is Li 4／3 Ti 5／3 O4, (ii) contains Li1Ti2O4, and (iii) contains Li 4／5 Ti 11／5 O4. Furthermore, regarding the configuration where Z≠0, Li is a preferred example. 4／3 Ti 4／3 Al 1／3 O4.

[0589] The aforementioned negative electrode mixture preferably further contains a binder, a thickener, and a conductive material.

[0590] As the binder described above, the same substances as those used in the positive electrode can be listed. 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, and particularly preferably 0.6% by mass or more. Furthermore, it is preferably 20% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, and particularly preferably 8% by mass or less. When the ratio of the binder to the negative electrode active material is higher than the above range, the proportion of binder in the binder dosage that does not contribute to the battery capacity increases, which may sometimes lead to a decrease in battery capacity. Conversely, when it is lower than the above range, it may sometimes lead to a decrease in the strength of the negative electrode.

[0591] Especially when the main component contains a rubbery polymer such as 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, more preferably 2% by mass or less. Furthermore, when the main component contains a fluorinated polymer such as polyvinylidene fluoride, the proportion relative to the negative electrode active material is typically 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more, and typically 15% by mass or less, preferably 10% by mass or less, more preferably 8% by mass or less.

[0592] As the aforementioned thickener, the same substances as those used in the positive electrode can be listed. 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. When the ratio of the thickener to the negative electrode active material is lower than the above range, the coatability may sometimes decrease significantly. When it exceeds the above range, the proportion of the negative electrode active material in the negative electrode active material layer decreases, sometimes resulting in a reduction in battery capacity or an increase in resistance between the negative electrode active materials.

[0593] Examples of conductive materials that can serve as negative electrodes include metallic materials such as copper or nickel, and carbon materials such as graphite and carbon black.

[0594] 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 type of aqueous solvent or organic solvent can be used.

[0595] 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, diethyltriamine, N,N-dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphoramide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, and hexane.

[0596] Materials that can be used as current collectors for negative electrodes include copper, nickel, and stainless steel. Among these, copper foil is preferred from the perspectives of ease of processing into thin films and cost.

[0597] The thickness of the current collector is typically 1 μm or more, preferably 5 μm or more, and typically less than 100 μm, preferably less than 50 μm. When the thickness of the negative electrode current collector is too thick, the overall capacity of the battery may decrease excessively; conversely, when it is too thin, operation may become difficult.

[0598] The negative electrode can be manufactured using conventional methods. For example, one method involves adding the aforementioned binder, thickener, conductive material, solvent, etc., to the negative electrode material to form a slurry, coating it onto the current collector, and then pressing it to achieve high density after drying. Alternatively, when using alloy materials, a thin film layer (negative electrode active material layer) containing the aforementioned negative electrode active material can be formed using methods such as vapor deposition, sputtering, or plating.

[0599] 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, more preferably 1.2 g·cm －3 The above, especially preferred, is 1.3 g·cm³. －3 The above, and preferably 2.2 g·cm³ －3 The following is more preferably 2.1 g·cm⁻¹ －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. When the density of the negative electrode active material on the current collector is higher than the above range, sometimes the negative electrode active material particles are destroyed, leading to an increase in initial irreversible capacity, or the permeability of the electrolyte to the area near the current collector / negative electrode active material interface decreases, resulting in poor high-current-density charge-discharge characteristics. Additionally, when the density is lower than the above range, sometimes the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume decreases.

[0600] The thickness of the negative electrode plate is designed in conjunction with the positive electrode plate used, and there are no particular limitations. It is desirable that the thickness of the compound layer after deducting the thickness of the core metal foil is generally 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more; and generally 300 μm or less, preferably 280 μm or less, more preferably 250 μm or less.

[0601] Alternatively, a negative electrode plate 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.

[0602] <Septum> The lithium-ion secondary battery of the present invention preferably also has a separator.

[0603] Regarding the material and shape of the aforementioned diaphragm, there are no particular limitations as long as it is stable with respect to the electrolyte and has excellent liquid retention properties; known diaphragms can be used. Among these, it is preferable to use a porous sheet or non-woven fabric-like material formed from a material stable with respect to the electrolyte of the present invention, such as resin, glass fiber, or inorganic materials, which has excellent liquid retention properties.

[0604] Materials used for resin and glass fiber membranes 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 combination or proportion of two or more materials. From the viewpoint of good electrolyte permeability and shutdown effect, the aforementioned membranes are preferably porous sheets or non-woven fabrics made from polyolefins such as polyethylene and polypropylene.

[0605] 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. When the separator is too thin compared to the above range, insulation and mechanical strength may decrease. Furthermore, when it is too thick compared to the above range, not only may battery performance such as rate capability decrease, but the overall energy density of the electrolyte battery may also decrease.

[0606] Furthermore, when using porous materials such as porous sheets or nonwoven fabrics as the diaphragm, the porosity of the diaphragm 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 range, there is a tendency for increased membrane resistivity and deteriorated rate performance. Conversely, if the porosity is too large compared to the above range, there is a tendency for decreased mechanical strength and reduced insulation properties of the diaphragm.

[0607] Furthermore, the average pore size of the membrane is arbitrary, typically 0.5 μm or less, preferably 0.2 μm or less, and usually 0.05 μm or more. When the average pore size is higher than the above range, short circuits are more likely to occur. Conversely, when it is lower than the above range, the membrane resistance sometimes increases and the rate capability decreases.

[0608] On the other hand, as inorganic materials, for example, oxides such as aluminum oxide or silicon dioxide, nitrides such as aluminum nitride or silicon nitride, and sulfates such as barium sulfate or calcium sulfate can be used, and materials in granular or fibrous form can be used.

[0609] As a form, it can take the form of a thin film, such as nonwoven fabric, woven fabric, or microporous membrane. When in thin film form, materials with a pore size of 0.01–1 μm and a thickness of 5–50 μm are suitable. Besides the aforementioned individual thin film shapes, a membrane can be formed by using a resin-based binder to create a composite porous layer containing the aforementioned inorganic particles on the surface of the positive and / or negative electrodes. For example, using fluororesin as a binder, a porous layer can be formed on both sides of the positive electrode with 90% alumina particles having a particle size less than 1 μm.

[0610] <Battery Design> The electrode assembly can be any configuration, such as a stacked structure consisting of a positive electrode plate and a negative electrode plate separated by a separator, or a structure in which the positive electrode plate and the negative electrode plate are wound into a vortex shape separated by a separator. The proportion of the volume of the electrode assembly in the internal volume of the battery (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.

[0611] When the electrode assembly occupancy rate is below the above range, the battery capacity decreases. When it is above the above range, there is less space, and sometimes the battery may reach high temperatures, causing component expansion or an increase in the vapor pressure of the liquid components of the electrolyte, resulting in an increase in internal pressure. This reduces the battery's charge-discharge repeatability and high-temperature storage characteristics, and may even cause the gas release valve that releases internal pressure to the outside to activate.

[0612] There are no particular limitations on the current collector structure, but in order to more effectively improve the high current density charge-discharge characteristics using the electrolyte of the present invention, a structure that reduces the resistance of the wiring portion and the joint portion is preferred. With such a reduction in internal resistance, the effects of using the electrolyte of the present invention can be particularly well utilized.

[0613] When the electrode assembly has the aforementioned stacked structure, it is preferable to use a structure formed by bundling the metal core portions of each electrode layer together and fusing them with terminals. As the area of ​​an electrode increases, the internal resistance also increases; therefore, it is suitable to provide multiple terminals within the electrode to reduce resistance. When the electrode assembly has the aforementioned wound structure, by providing multiple wire structures at the positive and negative electrodes respectively and bundling them together into terminals, the internal resistance can be reduced.

[0614] There are no particular restrictions on the material of the outer packaging shell, as long as it is a substance stable to the electrolyte used. Specifically, nickel-plated steel plates, stainless steel, aluminum or aluminum alloys, magnesium alloys, or laminated films of resin and aluminum foil can be used. From a lightweight perspective, aluminum or aluminum alloys and laminated films are suitable.

[0615] In the case of metal outer packaging shells, examples include welding metals together to form a sealed encapsulation structure using laser welding, resistance welding, or ultrasonic welding, or using the aforementioned metals with resin gaskets in between to form a riveted structure. In the case of outer packaging shells using laminated films, examples include outer packaging shells that form a sealed encapsulation structure by thermally fusing resin layers together. To improve sealing, a resin different from the resin used in the laminated film can be present between the resin layers. Particularly when a sealed structure is formed by thermally fusing resin layers with current collector terminals sandwiched between them, due to the bonding between the metal and resin, it is preferable to use a resin with polar groups or a modified resin with introduced polar groups as the resin sandwiched between them.

[0616] The lithium-ion secondary battery of the present invention can have any shape, including, for example, cylindrical, square, laminated, coin-shaped, and large shapes. The shapes and configurations of the positive electrode, negative electrode, and separator can be varied according to the shape of each battery.

[0617] In addition, a module having the lithium-ion secondary battery of the present invention is also one of the present inventions.

[0618] Alternatively, a lithium-ion secondary battery is also a preferred option. This lithium-ion secondary battery is characterized by having a positive electrode, a negative electrode, and the aforementioned electrolyte. The positive electrode includes a positive electrode current collector and a positive electrode active material layer containing Mn. Because it has a positive electrode active material layer containing Mn, the high-temperature storage characteristics of the aforementioned lithium-ion secondary battery are superior.

[0619] 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.

[0620] 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. When the content of the positive electrode active material in the positive electrode active material layer is low, the electrical capacity may sometimes become insufficient. Conversely, when the content is too high, the strength of the positive electrode may sometimes be insufficient.

[0621] The aforementioned positive electrode active material layer may also contain conductive materials, thickeners, and binders.

[0622] As the aforementioned binder, any material that is safe for the solvents and electrolytes used in the manufacture of the electrodes 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), and fluorinated rubber. The following substances are permitted: 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 exhibiting ion conductivity with alkali metal ions (especially lithium ions). These substances may be used individually or in combination or proportion in any way.

[0623] Regarding the binder content, based on the proportion of binder in the positive electrode active material layer, it 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. When the binder proportion is too low, the positive electrode active material may not be sufficiently retained, resulting in insufficient mechanical strength of the positive electrode and deterioration of battery performance such as cycle characteristics. Conversely, when the proportion is too high, it may sometimes lead to a decrease in battery capacity or conductivity.

[0624] Examples of thickeners mentioned above include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and their salts. One type can be used alone, or two or more can be used in any combination and proportion.

[0625] 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. Below this range, the coatability may sometimes decrease significantly. Above this range, the proportion of active material in the positive electrode active material layer decreases, sometimes resulting in reduced battery capacity or increased resistance between positive electrode active materials.

[0626] 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 materials such as carbon black such as acetylene black; and amorphous carbon such as needle coke. Each of these materials can be used individually or in combination or proportion of two or more in any way. The conductive material is typically used in the positive electrode active material layer at a content of 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, and typically 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less. When the content is below this range, conductivity may become insufficient. Conversely, when the content is above this range, battery capacity may decrease.

[0627] From the viewpoint of further improving high-temperature storage characteristics, it is preferable that the above-mentioned positive electrode current collector is made of a valve metal or its alloy. Examples of valve metals include aluminum, titanium, tantalum, and chromium. More preferably, the above-mentioned positive electrode current collector is made of aluminum or an aluminum alloy.

[0628] From the viewpoint of further improving high-temperature storage characteristics, it is preferable that the portion of the lithium-ion secondary battery that is electrically connected to the positive current collector and comes into contact with the electrolyte is also made of valve metal or its alloy. Particularly preferred are the battery outer casing, and the portions of the leads, safety valves, etc., housed within the battery outer casing, that are electrically connected to the positive current collector and come into contact with the non-aqueous electrolyte, made of valve metal or its alloy. Stainless steel covered with valve metal or its alloy may also be used.

[0629] The manufacturing method of the above positive electrode is as described above. For example, the following methods can be used: add the above binder, thickener, conductive material, solvent, etc. to the above positive electrode active material to make a slurry-like positive electrode mixture, coat it on the above positive electrode current collector, dry it and then press it to make it high density.

[0630] The negative electrode is constructed as described above.

[0631] The aforementioned double-layer capacitor may have a positive electrode, a negative electrode, and the aforementioned electrolyte.

[0632] 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.

[0633] The polarization electrode used in this invention, which is primarily composed of activated carbon, preferably contains non-activated carbon with a large specific surface area and conductive agents such as carbon black that impart electronic conductivity. The polarization electrode can be formed by various methods. For example, a polarization electrode composed of activated carbon and carbon black can be formed by mixing activated carbon powder, carbon black, and phenolic resin, followed by pressure molding and firing and activation in an inert gas atmosphere and a water vapor atmosphere. Preferably, this polarization electrode is bonded to the current collector using a conductive binder or the like.

[0634] Alternatively, a polarizing electrode can be fabricated by mixing activated carbon powder, carbon black, and a binder in the presence of alcohol, molding the mixture into sheets, and then drying it. For example, polytetrafluoroethylene (PTFE) can be used as the binder. Alternatively, a polarizing electrode integrated with the current collector can be fabricated by mixing activated carbon powder, carbon black, a binder, and a solvent to form a slurry, coating the slurry onto the metal foil of the current collector, and then drying it.

[0635] A double-charge-layer capacitor can be formed by using polarized electrodes with activated carbon as the main body on both poles, or a structure using a non-polarized electrode on one side can be adopted. For example, it can be a structure composed of a positive electrode composed of battery active materials such as metal oxides and a negative electrode composed of polarized electrodes with activated carbon as the main body; or a structure composed of a negative electrode composed of carbon materials that can reversibly absorb and release lithium ions, or a negative electrode of lithium metal or lithium alloy, and a polarized positive electrode composed of activated carbon as the main body.

[0636] Alternatively, it can replace activated carbon, or be used in combination with activated carbon and carbonaceous materials such as carbon black, graphite, expanded graphite, porous carbon, carbon nanotubes, carbon nanotubes, and Ketjen black.

[0637] As a non-polarized electrode, a carbon material capable of reversibly absorbing and releasing lithium ions is preferred, allowing the carbon material to absorb lithium ions before being used as the electrode. In this case, a lithium salt is used as the electrolyte. Based on this configuration, a higher withstand voltage exceeding 4V can be obtained for the double-layer capacitor.

[0638] The solvent used in the preparation of the slurry for electrode fabrication is preferably a solvent that dissolves the binder. Corresponding to the type of binder, appropriate solvents such as N-methylpyrrolidone, dimethylformamide, toluene, xylene, isophorone, methyl ethyl ketone, ethyl acetate, methyl acetate, dimethyl phthalate, ethanol, methanol, butanol, or water can be selected.

[0639] Activated carbon used as polarizing electrodes includes phenolic resin activated carbon, coconut shell activated carbon, and petroleum coke activated carbon. From the perspective of obtaining a large capacity, petroleum coke-based activated carbon or phenolic resin-based activated carbon is preferred. Furthermore, activated carbon activation methods include steam activation and molten KOH activation; from the perspective of obtaining even greater capacity, activated carbon obtained through molten KOH activation is preferred.

[0640] Preferred conductive agents used 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 agents such as carbon black used in polarization electrodes, to obtain good conductivity (low internal resistance) and because an excessive amount reduces the capacity of the product, it is preferably 1 to 50% by mass in the total amount with activated carbon.

[0641] Furthermore, the activated carbon used as the polarization electrode has an average particle size of less than 20 μm and a specific surface area of ​​1500–3000 m². 2 Activated carbon at a concentration of / g is preferred because it can produce a double-layer capacitor with high capacity and low internal resistance. 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 products of furfuryl alcohol resin, or sintered products of phenolic varnish resin.

[0642] The current collector can be made of any material that is resistant to chemical and electrochemical corrosion. For current collectors with activated carbon as the main polarized electrode, stainless steel, aluminum, titanium, or tantalum are preferred. Among these, stainless steel or aluminum are particularly preferred materials in terms of both the characteristics and cost of the resulting double-layer capacitor. For current collectors with carbon materials as the main electrode capable of reversibly adsorbing and releasing lithium ions, stainless steel, copper, or nickel are preferred.

[0643] In addition, in order to pre-absorb lithium ions in a carbon material that can reversibly absorb and release lithium ions, the following methods are used: (1) mixing powdered lithium with a carbon material that can reversibly absorb and release lithium ions; (2) placing a lithium foil on an electrode formed by a carbon material that can reversibly absorb and release lithium ions and a binder, and immersing the electrode in an electrolyte containing lithium salt while in electrical contact with the electrode, thereby ionizing the lithium and allowing the lithium ions to enter the carbon material; (3) placing an electrode formed by a carbon material that can reversibly absorb and release lithium ions and a binder on the negative electrode side and placing lithium metal on the positive electrode side, immersing the electrode in a non-aqueous electrolyte with lithium salt as the electrolyte, and passing current through it, so that lithium enters the carbon material in an ionized state in an electrochemical manner.

[0644] As double-layer capacitors, wound double-layer capacitors, multilayer 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.

[0645] For example, a wound double-layer capacitor is assembled in the following way: the positive and negative electrodes, which are composed of a stack of current collectors and electrode layers (electrodes), are wound together with a diaphragm to form a wound element. The wound element is placed in a housing made of aluminum or the like, filled with electrolyte, preferably a non-aqueous electrolyte, and then sealed with a rubber sealing body.

[0646] As a diaphragm, existing and known materials and compositions can be used. Examples include porous polyethylene membranes, polytetrafluoroethylene, nonwoven fabrics made of polypropylene fibers or glass fibers, cellulose fibers, etc.

[0647] Alternatively, known methods can be used to fabricate a laminated double-layer capacitor formed by stacking sheet-shaped positive and negative electrodes with an electrolyte and a separator, or a coin-shaped double-layer capacitor formed by fixing the positive and negative electrodes with a gasket and separating them with an electrolyte and a separator.

[0648] The electrolyte of the present invention is useful as an electrolyte for large lithium-ion secondary batteries used in hybrid electric vehicles or distributed power sources, or as an electrolyte for double-layer capacitors.

[0649] Example The present invention will be described in more detail below with reference to embodiments, but the present invention is not limited thereto.

[0650] Unless otherwise specified, the term "yield" refers to molar yield.

[0651] [Symbols and abbreviations in the examples and tables] (Fluorocarboxylate compounds) Compound F: HCF2COOLi Compound G: CF3COOLi Compound H: CFH2COOLi Compound I: CF3CH2COOLi Compound J: HCF2CF2COOLi.

[0652] (carbonate) chain carbonates (a): Dimethyl carbonate (b): Ethyl methyl carbonate (c): Diethyl carbonate (d): CF3CH2OCOOCH3.

[0653] Cyclic carbonates EC: Ethylene carbonate PC: Propylene carbonate FEC: 4-Fluoro-1,3-dioxolane-2-one.

[0654] [Moisture content determination] The moisture content of lithium difluoroacetate in each example and Comparative Example 4 was determined using the Karl Fischer method in a drying chamber (dew point below -40°C). As for Comparative Example 4, a purchased product (Lithium difluoroacetate manufactured by APOLLO SCIENTIFIC) was used.

[0655] Example 1 (Preparation of Compound F) Ethyl difluoroacetate (100 g, 0.8065 mol) was added to the reactor and stirred at room temperature. Lithium hydroxide (17.4 g, 0.7258 mol) was added in portions and stirred at room temperature until the reaction was complete. After the reaction was complete, the liquid medium was removed from the reaction mixture by distillation under reduced pressure to give compound F (lithium difluoroacetate) as a fluorinated carboxylate (64.9 g, 88% yield) (water content: 2340 ppm).

[0656] Example 2 (Preparation of Compound F) Ethyl difluoroacetate (100 g, 0.8065 mol) and ethanol (200 g) were added to the reactor and stirred at room temperature. While maintaining the temperature below 70 °C, lithium hydroxide (17.4 g, 0.7258 mol) was added in portions, and the mixture was stirred at room temperature until the reaction was complete. After the reaction was complete, the liquid medium was removed from the reaction mixture by distillation under reduced pressure to give compound F (lithium difluoroacetate) (62.3 g, 85% yield) as a fluorinated carboxylate (water content: 1462 ppm).

[0657] Examples 3-16 (Preparation of Compound F) Referring to Example 1, compound F (lithium difluoroacetate) with various moisture contents was obtained as described in Table 1. The moisture content was adjusted by performing azeotropic dehydration and / or adding trace amounts of water.

[0658] Example 17 (Preparation of Compound G) Compound G was prepared in the same manner as in Example 2, except that ethyl trifluoroacetate was used instead of ethyl difluoroacetate.

[0659] Example 18 (Preparation of Compound H) Compound H was prepared in the same manner as in Example 2, except that ethyl monofluoroacetate was used instead of ethyl difluoroacetate.

[0660] Example 19 (Preparation of Compound I) Compound I was prepared in the same manner as in Example 2, except that ethyl 3-trifluoropropionate was used instead of ethyl difluoroacetate and tetrahydrofuran was used instead of ethanol.

[0661] Example 20 (Preparation of Compound J) Compound J was prepared in the same manner as in Example 2, except that ethyl 2-difluoro-3-difluoropropionate was used instead of ethyl difluoroacetate and acetonitrile was used instead of ethanol.

[0662] Test case The moisture content of lithium difluoroacetate in Examples 1-21 and Comparative Example 4 was determined by Karl Fischer method in a drying chamber (dew point below -40°C). As Comparative Example 4, a purchased product (Lithium difluoroacetate manufactured by APOLLO SCIENTIFIC) was used. The results are shown in the "Moisture Content" column of Table 1.

[0663] Experiment 1 (Lithium Battery Evaluation) Electrolytes for Examples 1 to 21 and Comparative Examples 1 to 4 were prepared as follows (wherein, as shown in Table 1, no fluorinated carboxylate compounds were added in Comparative Examples 1 to 3 (Reference Examples)). Lithium-ion secondary batteries were fabricated using the obtained electrolytes, and their resistance increase rate and cycle capacity retention rate were evaluated respectively.

[0664] (Preparation of electrolyte) Under a dry argon atmosphere, chain carbonates and cyclic carbonates were mixed in the proportions shown in Table 1. The amounts of fluorinated carboxylate compounds obtained in the above examples, as shown in Table 1, were added to this solution, followed by the addition of dry LiPF6 to achieve a concentration of 1.2 mol / L, thus obtaining a non-aqueous electrolyte. The proportions of the fluorinated carboxylate compounds are expressed as a percentage of mass relative to the electrolyte.

[0665] (Making the negative electrode) Artificial graphite powder was used as the negative electrode active material; an aqueous dispersion of sodium carboxymethyl cellulose (1% by mass) was used as the thickener; and an aqueous dispersion of styrene-butadiene rubber (50% by mass) was used as the binder. These materials were mixed in an aqueous solvent to prepare a slurry-like negative electrode mixture. The solid content ratio of the negative electrode active material, thickener, and binder was 98.1 / 0.9 / 1.0 (by mass). This mixture was uniformly coated onto a 20 μm thick copper foil, dried, and then compressed using a press to form the negative electrode.

[0666] (The production of the positive electrode) LiNi is used as the positive electrode active material. 0.6 Mn 0.2 Co 0.2 O2; acetylene black was used as the conductive material; and an N-methyl-2-pyrrolidone dispersion of polyvinylidene fluoride (PVdF) was used as the binder. These were mixed to prepare a slurry-like positive electrode mixture. The solid content ratio of the positive electrode active material, conductive material, and binder was 97 / 1.5 / 1.5 (mass %). The obtained positive electrode mixture slurry was uniformly coated onto a 20 μm thick aluminum foil current collector, dried, and then compressed using a press to form the positive electrode.

[0667] (The manufacture of lithium-ion secondary batteries) A battery element is fabricated by stacking the negative electrode, positive electrode, and polyethylene separator manufactured as described above in the order of negative electrode, separator, and positive electrode.

[0668] After inserting the battery element into a bag made of a laminated film consisting of resin layers covering two sides of an aluminum sheet (40 μm thick) with the positive and negative terminals protruding, the electrolytes of Examples 1-22 and Comparative Examples 1-3 were injected into the bag respectively, and vacuum sealing was performed to produce a sheet-like lithium-ion secondary battery.

[0669] <High-Temperature Cycling Capacity Retention> With the aforementioned secondary battery clamped in a pressurized state, it is charged at 45°C using a constant current-constant voltage (CC / CV) charge at a current equivalent to 0.2C until 4.2V (0.1C cutoff). Then, it is discharged at a constant current of 0.2C to 3V, constituting one cycle. The initial discharge capacity is calculated based on the discharge capacity of the third cycle. Here, 1C represents the current value required to discharge the battery to its reference capacity in one hour; for example, 0.2C represents 1 / 5 of that current value. By repeating the cycle, the discharge capacity after 600 cycles is taken as the cycle capacity. The ratio of the discharge capacity after 600 cycles to the initial discharge capacity is calculated and taken as the cycle capacity retention rate (%).

[0670] (Discharge capacity after 600 cycles) ÷ (Initial discharge capacity) × 100 = Cycle capacity retention rate (%) (Rate of increase in resistance) A charge-discharge cycle performed under specified charge-discharge conditions (charging at 0.2C with a specified voltage until the charging current reaches 1 / 10C, ​​and discharging at a current equivalent to 1C to 3.0V) is considered as one cycle. The resistance is measured after 3 cycles and after 600 cycles. The measurement temperature is 25°C. The rate of increase in resistance after 600 cycles is calculated based on the following formula.

[0671] The results are shown in Table 1.

[0672] The rate of increase in resistance after 600 cycles (%) = Resistance after 600 cycles (Ω) / Resistance after 3 cycles (Ω) × 100.

[0673] [Table 1] .

Claims

1. A method for producing a compound represented by formula (P1), characterized in that: Step A includes reacting the compound shown in formula (S1) with the compound shown in formula (S2) or their hydrates. Formula (P1): (B) 1f ) mp (A) 1 ) np In formula (P1), B 1f For RfCOO, Rf is a hydrocarbon group having one or more fluorine atoms. A 1 Groups other than H mp is (A 1 (value) × np / (B) 1f The valence number is a number that is either 1 or 2. np is (B) 1f (value) × mp / (A) 1 The valence number is 1. A 1 The price is 1 or 2. B 1f The value is 1; Formula (S1): (B) 1f (R) 1 ) In formula (S1), B 1f The meaning is the same as above. R 1 It is an organic group. But R 1 With A 1 They are different groups; (S2):(A 1 ) ms2 (B 2 ) ns2 In formula (S2), A 1 The meaning is the same as above. B 2 It can be OH, CO3 or HCO3. ms2 is (B 2 (valence) × ns2 / (A) 1 The valence number is a number that is either 1 or 2. ns2 is (A 1 (value) × ms² / (B) 2 The valence (of which), and is either 1 or 2.

2. The manufacturing method as described in claim 1, characterized in that: A 1 It consists of metal atoms or ammonium.

3. The manufacturing method as described in claim 1 or 2, characterized in that: It also includes a step B that removes the compound of formula (P2) generated as a byproduct in step A. Formula (P2): (R) 1 ) op (B) 2 ) In formula (P2), B 2 and R 1 The meaning is the same as above. op is (B) 2 (price) / (R) 1 The valence of the number is 1 or 2.

4. The manufacturing method as described in claim 1 or 2, characterized in that: Rf is a C1-6 alkyl group having one or more fluorine atoms.

5. The manufacturing method as described in claim 1 or 2, characterized in that: Rf is a C1-3 alkyl group having two or more fluorine atoms.

6. The manufacturing method as described in claim 1 or 2, characterized in that: A 1 It consists of alkali metal atoms.

7. The manufacturing method as described in claim 1 or 2, characterized in that: A 1 For Li.

8. The manufacturing method as described in claim 1 or 2, characterized in that: B 2 It is OH.

9. An additive for electrochemical devices, characterized in that: Containing a compound of formula (P1A) and water in amounts of 0 to 50,000 ppm by mass relative to the compound of formula (P1A), Formula (P1A): RfCOOA d In formula (P1A), Rf is an organic group having one or more fluorine atoms. A d It consists of metal atoms.

10. An electrolyte, characterized in that: It contains the additive for electrochemical devices as described in claim 9.

11. An electrochemical device, characterized in that: It has the electrolyte as described in claim 10.

12. A lithium-ion secondary battery, characterized in that: It has the electrolyte as described in claim 10.

13. A compound represented by formula (P1A), characterized in that: Moisture content is below 50,000 ppm by mass. Formula (P1A): RfCOOA d In formula (P1A), Rf is an organic group having one or more fluorine atoms. A d It consists of Li atoms.

14. A composition, characterized in that: Containing a compound of formula (P1A) and water at a concentration of less than 50,000 ppm by mass relative to the compound of formula (P1), Formula (P1A): RfCOOA d In formula (P1A), Rf is an organic group having one or more fluorine atoms. A d It consists of Li atoms.

15. The compound according to claim 13, characterized in that: Manufactured by the manufacturing method according to any one of claims 1 to 8.

16. The composition of claim 14, characterized in that: Manufactured by the manufacturing method according to any one of claims 1 to 8.

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