Non-aqueous electrolyte for battery and lithium secondary battery

Abstract

A non-aqueous electrolyte for a battery, comprising: an additive A, wherein the additive A is at least one selected from the group consisting of compounds represented by the following formula (A); an additive B, wherein the additive B is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate; and an additive C, wherein the additive C is at least one selected from the group consisting of compounds having a sulfur-oxygen bond. In formula (A), R 1 represents a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, R 2 ~R 4 Each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms. #imgabs0#

Description

Technical Field

[0001] The present disclosure relates to a non-aqueous electrolyte for a battery and a lithium secondary battery. Background Art

[0002] Various studies have been conducted on nonaqueous electrolytes used in batteries such as lithium secondary batteries.

[0003] For example, Patent Document 1 discloses a non-aqueous electrolyte having excellent safety, high conductivity and low viscosity, wherein the non-aqueous electrolyte comprises the following [A] non-aqueous solvent and [B] electrolyte, wherein the [A] non-aqueous solvent comprises fluorocarbonate, cyclic carbonate and chain carbonate, wherein (i) the content of cyclic carbonate is 2 to 63 mol %, (ii) the content of chain carbonate is 2 to 63 mol %, and (iii) the content of fluorocarbonate is 60 to 96 mol % (wherein the sum of (i) to (iii) does not exceed 100 mol %), and the fluorocarbonate is a compound having a specific chemical structure.

[0004] In addition, in Patent Document 2, in an electrochemical element (especially a high-voltage lithium secondary battery) in which the positive electrode potential of the electrochemical element in a fully charged state is 4.35V or more relative to the potential of metallic lithium, as a non-aqueous electrolyte with little decrease in battery capacity associated with charge and discharge cycles at high temperatures and little gas generation during high-temperature storage, the following non-aqueous electrolyte for an electrochemical element is disclosed, the non-aqueous electrolyte comprising a non-aqueous solvent containing a cyclic carbonate and a chain carbonate as main components and an electrolyte solute, Wherein, more than 60 weight % of cyclic carbonate is 4-fluoroethylene carbonate, more than 25 weight % of chain carbonate is at least one fluorinated chain carbonate selected from the group consisting of methyl carbonate-2,2,2-trifluoroethyl ester, ethyl carbonate-2,2,2-trifluoroethyl ester and di-2,2,2-trifluoroethyl carbonate, and the weight ratio of cyclic carbonate to chain carbonate is 3:97 to 35:65, and based on the potential of metallic lithium, the positive electrode potential in a fully charged state is more than 4.35V.

[0005] Patent Document 3 discloses a nonaqueous electrolyte containing a cyclic sulfate ester compound of a specific structure as a nonaqueous electrolyte capable of improving the capacity retention performance of a battery and significantly suppressing a decrease in the open circuit voltage of the battery during charge storage.

[0006] Patent Document 1: Japanese Patent No. 4392726

[0007] Patent Document 2: Japanese Patent No. 4976715

[0008] Patent Document 3: Japanese Patent No. 5524347 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, for batteries using a non-aqueous electrolyte solution containing a specific fluorinated cyclic carbonate such as 4-fluoroethylene carbonate (specifically, a compound represented by formula (A) described below, the same applies hereinafter), there is sometimes a demand for further reduction in battery resistance after storage.

[0011] An object of one embodiment of the present disclosure is to provide a non-aqueous electrolyte for a battery, which is a non-aqueous electrolyte for a battery containing a specific fluorinated cyclic carbonate and can reduce the battery resistance after storage.

[0012] Another aspect of the present disclosure aims to provide a lithium secondary battery which uses a non-aqueous electrolyte solution containing a specific fluorinated cyclic carbonate and can reduce the battery resistance after storage.

[0013] Means for solving problems

[0014] Means for solving the above-mentioned problems include the following aspects.

[0015] <1> A non-aqueous electrolyte for a battery, comprising:

[0016] Additive A, wherein the additive A is at least one selected from the group consisting of compounds represented by the following formula (A);

[0017] Additive B, wherein the additive B is at least one selected from the group consisting of monofluoro lithium phosphate and difluoro lithium phosphate;

[0018] The additive C is at least one selected from the group consisting of compounds having a sulfur-oxygen bond.

[0019] [Chemical formula 1]

[0020]

[0021] In formula (A), R 1 represents a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, R 2 ~R 4 Each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0022] <2> The non-aqueous electrolyte for a battery according to <1>, wherein the additive C is at least one selected from the group consisting of cyclic sulfate ester compounds, cyclic sulfonate ester compounds, substituted or unsubstituted sulfobenzoic anhydride, fluorosulfonyl compounds, and lithium sulfonate compounds.

[0023] <3> A non-aqueous electrolyte for a battery as described in <1> or <2>, wherein the additive C is at least one selected from the group consisting of a compound represented by the following formula (C1), a compound represented by the following formula (C2), a compound represented by the following formula (C3), a compound represented by the following formula (C4), and a compound represented by the following formula (C5).

[0024] [Chemical formula 2]

[0025]

[0026] In formula (C1), R 11 ~R 14 Each independently represents a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b). In formula (1a) and formula (1b), * represents a bonding position.

[0027] In formula (C2), R 21 ~R 24 Each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0028] In formula (C3), R 31 ~R 34 Each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a halogenated hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a halogenated hydrocarbonoxy group having 1 to 6 carbon atoms.

[0029] In formula (C4), R 41 It represents a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0030] In formula (C5), R 51 It represents a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0031] <4> The nonaqueous electrolyte for a battery according to any one of <1> to <3>, which is used for a battery containing a negative electrode active material containing a graphite material.

[0032] <5> The non-aqueous electrolyte solution for a battery according to <4>, wherein the negative electrode active material further comprises silicon oxide represented by the following composition formula (1).

[0033] SiO X …Composition formula (1)

[0034] [In the composition formula (1), X represents 0.5 or more and less than 1.6.]

[0035] <6> The non-aqueous electrolyte for a battery according to any one of <1> to <5>, wherein the content of the additive A is 0.001% by mass to 20% by mass based on the total amount of the non-aqueous electrolyte for a battery.

[0036] <7> The non-aqueous electrolyte for a battery according to any one of <1> to <6>, wherein the content of the additive B is 0.001% by mass to 10% by mass based on the total amount of the non-aqueous electrolyte for a battery.

[0037] <8> The non-aqueous electrolyte for a battery according to any one of <1> to <7>, wherein the content of the additive C is 0.001% by mass to 10% by mass based on the total amount of the non-aqueous electrolyte for a battery.

[0038] <9> A lithium secondary battery comprising: a positive electrode; a negative electrode containing a negative electrode active material including a graphite material; and the nonaqueous electrolyte for a battery according to any one of <1> to <8>.

[0039] <10> The lithium secondary battery according to <9>, wherein the negative electrode active material further includes silicon oxide represented by the following composition formula (1).

[0040] SiO X …Composition formula (1)

[0041] [In the composition formula (1), X represents 0.5 or more and less than 1.6.]

[0042] <11> A lithium secondary battery obtained by charging and discharging the lithium secondary battery according to <9> or <10>.

[0043] Effects of the Invention

[0044] According to one embodiment of the present disclosure, a non-aqueous electrolyte for a battery can be provided, which is a non-aqueous electrolyte for a battery containing a specific fluorinated cyclic carbonate and can reduce the battery resistance after storage.

[0045] According to another aspect of the present disclosure, there is provided a lithium secondary battery which uses a non-aqueous electrolyte solution containing a specific fluorinated cyclic carbonate and which can reduce the battery resistance after storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] [ Figure 1 ] is a schematic three-dimensional diagram showing an example of a laminated battery which is an example of a lithium secondary battery of the present disclosure.

[0047] [ Figure 2 ] for being contained in Figure 1 A schematic cross-sectional view in the thickness direction of a stacked electrode body in a laminated battery is shown.

[0048] [ Figure 3 ] is a schematic cross-sectional view showing an example of a button-type battery which is another example of the lithium secondary battery of the present disclosure. DETAILED DESCRIPTION

[0049] In this specification, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0050] In the present specification, when a plurality of substances belonging to each component are present in a composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified.

[0051] [Non-aqueous electrolyte for batteries]

[0052] The non-aqueous electrolyte solution for a battery of the present disclosure (hereinafter also referred to as “non-aqueous electrolyte solution”) contains:

[0053] Additive A, wherein the additive A is at least one selected from the group consisting of compounds represented by the following formula (A);

[0054] Additive B, wherein the additive B is at least one selected from the group consisting of monofluoro lithium phosphate and difluoro lithium phosphate;

[0055] The additive C is at least one selected from the group consisting of compounds having a sulfur-oxygen bond.

[0056] [Chemical formula 3]

[0057]

[0058] In formula (A), R 1 represents a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, R 2 ~R 4 Each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0059] In some cases, it is required that the battery using the non-aqueous electrolyte solution containing the additive A further reduce the battery resistance after storage.

[0060] According to the non-aqueous electrolyte of the present disclosure, even if it is a non-aqueous electrolyte containing the additive A, the battery resistance after storage can be reduced.

[0061] The reason why the above effects are exerted can be presumed as follows.

[0062] The battery resistance may increase in a battery using a nonaqueous electrolyte solution containing the additive A. The increase in battery resistance may be caused by reductive decomposition of the additive A on the negative electrode, oxidative decomposition of the reductive decomposition product on the positive electrode, and the like.

[0063] In this regard, the non-aqueous electrolyte of the present disclosure contains additives B and C in addition to additive A. It is believed that a high-quality film can be formed on the electrode by the combination of additives A, additive B, and additive C. It is believed that the effect of this excellent film can achieve a reduction in battery resistance before storage and / or suppression of battery resistance increase during storage, and as a result, the battery resistance after storage can be reduced.

[0064] <Additive A>

[0065] The additive A is at least one selected from the group consisting of compounds represented by formula (A).

[0066] [Chemical formula 4]

[0067]

[0068] In formula (A), R 1 represents a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, R 2 ~R 4 Each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0069] In the present disclosure, a fluorinated hydrocarbon group having 1 to 6 carbon atoms refers to a hydrocarbon group having 1 to 6 carbon atoms substituted with at least one fluorine atom.

[0070] In formula (A), R 1 The fluorinated hydrocarbon group having 1 to 6 carbon atoms may be a linear fluorinated hydrocarbon group or a fluorinated hydrocarbon group having a branched chain and / or a ring structure.

[0071] In formula (A), R 1The fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by ] includes, for example, fluoroalkyl groups such as fluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, perfluoroethyl, 2,2,3,3-tetrafluoropropyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroisopropyl, and perfluoroisobutyl; fluoroalkenyl groups such as 2-fluorovinyl, 2,2-difluorovinyl, 2-fluoro-2-propenyl, 3,3-difluoro-2-propenyl, 2,3-difluoro-2-propenyl, 3,3-difluoro-2-methyl-2-propenyl, 3-fluoro-2-butenyl, perfluorovinyl, perfluoropropenyl, and perfluorobutenyl; and the like.

[0072] Among them, a fluoroalkyl group having 1 to 6 carbon atoms is preferred, a fluoroalkyl group having 1 to 3 carbon atoms is more preferred, a fluoromethyl group, a difluoromethyl group, or a trifluoromethyl group is further preferred, and a trifluoromethyl group is particularly preferred.

[0073] In formula (A), R 2 ~R 4 The hydrocarbon group having 1 to 6 carbon atoms represented may be a linear hydrocarbon group or a hydrocarbon group having a branched chain and / or a ring structure.

[0074] In formula (A), R 2 ~R 4 The hydrocarbon group having 1 to 6 carbon atoms represented by may be exemplified by:

[0075] Alkyl groups such as methyl, ethyl, n-propyl, isopropyl, 1-ethylpropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, 1-methylpentyl, n-hexyl, isohexyl, sec-hexyl, and tert-hexyl;

[0076] Alkenyl groups such as vinyl, 1-propenyl, allyl, 1-butenyl, 2-butenyl, 3-butenyl, pentenyl, hexenyl, isopropenyl, 2-methyl-2-propenyl, 1-methyl-2-propenyl, and 2-methyl-1-propenyl;

[0077] Phenyl; etc.

[0078] Among them, a phenyl group or an alkyl group having 1 to 6 carbon atoms is preferred, an alkyl group having 1 to 6 carbon atoms is more preferred, an alkyl group having 1 to 3 carbon atoms is further preferred, a methyl group or an ethyl group is further preferred, and a methyl group is particularly preferred.

[0079] In formula (A), R 1 A fluorine atom is preferred.

[0080] In formula (A), R 2 ~R 4, each independently preferably is a hydrogen atom, a fluorine atom, or a methyl group, more preferably a hydrogen atom or a fluorine atom, particularly preferably a hydrogen atom.

[0081] As a compound represented by formula (A),

[0082] Preferably, 4-fluoroethylene carbonate (FEC for short), 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, or 4-trifluoromethylethylene carbonate is used.

[0083] More preferably, 4-fluoroethylene carbonate, 4,4-difluoroethylene carbonate, or 4,5-difluoroethylene carbonate,

[0084] 4-Fluoroethylene carbonate is particularly preferred.

[0085] Relative to the total amount of the non-aqueous electrolyte, the content of additive A is preferably 0.001 mass % to 20 mass %, more preferably 0.001 mass % to 15 mass %, further preferably 0.001 mass % to 10 mass %, further preferably 0.001 mass % to 7 mass %, further preferably 0.001 mass % to 5 mass %, further preferably 0.01 mass % to 5 mass %, further preferably 0.1 mass % to 5 mass %, further preferably 1 mass % to 5 mass %.

[0086] <Additive B>

[0087] Additive B is selected from lithium monofluorophosphate (Li 2 PO 3 F) and lithium difluorophosphate (LiPO 2 F 2 ; hereinafter also referred to as "LiDFP") is a group consisting of at least one.

[0088] Additive B preferably comprises lithium difluorophosphate.

[0089] Relative to the total amount of the non-aqueous electrolyte, the content of additive B is preferably 0.001 mass % to 10 mass %, more preferably 0.001 mass % to 5.0 mass %, further preferably 0.001 mass % to 3.0 mass %, further preferably 0.01 mass % to 3.0 mass %, further preferably 0.1 mass % to 3.0 mass %, further preferably 0.1 mass % to 2.0 mass %, further preferably 0.3 mass % to 1.5 mass %.

[0090] <Additive C>

[0091] The additive C is at least one selected from the group consisting of compounds having a sulfur-oxygen bond.

[0092] It is considered that the sulfur-oxygen bond in the additive C is involved in the formation of the aforementioned film on the electrode.

[0093] The additive C is preferably at least one selected from the group consisting of cyclic sulfate ester compounds, cyclic sulfonate ester compounds (ie, sultone compounds), substituted or unsubstituted sulfobenzoic anhydride, fluorosulfonyl compounds, and lithium sulfonate compounds.

[0094] The additive C is more preferably at least one selected from the group consisting of a compound represented by the following formula (C1), a compound represented by the following formula (C2), a compound represented by the following formula (C3), a compound represented by the following formula (C4), and a compound represented by the following formula (C5).

[0095] The compound represented by the following formula (C1) is an example of a cyclic sulfate ester compound.

[0096] The compound represented by the following formula (C2) is an example of a cyclic sulfonate compound.

[0097] The compound represented by the following formula (C3) is an example of a substituted or unsubstituted sulfobenzoic anhydride.

[0098] The compound represented by the following formula (C4) is an example of a fluorosulfonyl compound.

[0099] The compound represented by the following formula (C5) is an example of the lithium sulfonate compound.

[0100] (Compound represented by formula (C1))

[0101] The compound represented by formula (C1) is shown below.

[0102] [Chemical formula 5]

[0103]

[0104] In formula (C1), R 11 ~R 14 Each independently represents a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b). In formula (1a) and formula (1b), * represents a bonding position.

[0105] In formula (C1), R 11 ~R 14 The hydrocarbon group having 1 to 6 carbon atoms represented may be a linear hydrocarbon group or a hydrocarbon group having a branched chain and / or a ring structure.

[0106] In formula (C1), R 11 ~R 14 Specific examples of the hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in formula (A) 2 ~R 4The same applies to specific examples of the hydrocarbon group having 1 to 6 carbon atoms.

[0107] In formula (C1), R 11 ~R 14 The hydrocarbon group having 1 to 6 carbon atoms represented by is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.

[0108] In formula (C1), R 11 ~R 14 The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0109] Specific examples of the compound represented by formula (C1) include compounds represented by the following formulas (C1-1) to (C1-4) (hereinafter also referred to as compound (C1-1) to compound (C1-4) respectively), but the compound represented by formula (C1) is not limited to these specific examples.

[0110] Among these, compounds (C1-1) to (C1-4) are particularly preferred.

[0111] [Chemical formula 6]

[0112]

[0113] (Compound represented by formula (C2))

[0114] The compound represented by formula (C2) is shown below.

[0115] [Chemical formula 7]

[0116]

[0117] In formula (C2), R 21 ~R 24 Each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0118] In formula (C2), R 21 ~R 24 The hydrocarbon group having 1 to 6 carbon atoms represented may be a linear hydrocarbon group or a hydrocarbon group having a branched chain and / or a ring structure.

[0119] In formula (C2), R 21 ~R 24 Specific examples of the hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in formula (A) 2 ~R 4 The same applies to specific examples of the hydrocarbon group having 1 to 6 carbon atoms.

[0120] In formula (C2), R 21 ~R 24 The hydrocarbon group having 1 to 6 carbon atoms represented by is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.

[0121] In formula (C2), R 21 ~R 24 The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0122] In formula (C2), R 21 ~R 24 The fluorinated hydrocarbon group having 1 to 6 carbon atoms may be a linear fluorinated hydrocarbon group or a fluorinated hydrocarbon group having a branched chain and / or a ring structure.

[0123] In formula (C2), R 21 ~R 24 Specific examples of the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in the formula (A) 2 ~R 4 The specific examples of the fluorinated hydrocarbon group having 1 to 6 carbon atoms are the same as those shown in FIG.

[0124] In formula (C2), R 21 ~R 24 The fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably a fluorinated alkyl group, a fluorinated alkenyl group, or a fluorinated alkynyl group, more preferably a fluorinated alkyl group or a fluorinated alkenyl group, and particularly preferably a fluorinated alkyl group.

[0125] In formula (C2), R 21 ~R 24 The number of carbon atoms in the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0126] In formula (C2), R 21 ~R 24 , each independently preferably a hydrogen atom, a fluorine atom, a methyl group, an ethyl group, a trifluoromethyl group, or a pentafluoroethyl group, more preferably a hydrogen atom or a methyl group, particularly preferably a hydrogen atom.

[0127] Specific examples of the compound represented by formula (C2) include compounds represented by the following formulas (C2-1) to (C2-21) (hereinafter also referred to as compound (C2-1) to compound (C2-21) respectively), but the compound represented by formula (C2) is not limited to these specific examples.

[0128] Among these, compound (C2-1) (ie, 1,3-propene sultone; hereinafter also referred to as "PRS") is particularly preferred.

[0129] [Chemical formula 8]

[0130]

[0131] (Compound represented by formula (C3))

[0132] The compound represented by formula (C3) is shown below.

[0133] [Chemical formula 9]

[0134]

[0135] In formula (C3), R 31 ~R 34 Each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a halogenated hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a halogenated hydrocarbonoxy group having 1 to 6 carbon atoms.

[0136] In formula (C3), the halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom, a chlorine atom or a bromine atom, further preferably a fluorine atom or a chlorine atom, and further preferably a fluorine atom.

[0137] In formula (C3), R 31 ~R 34 The hydrocarbon group having 1 to 6 carbon atoms represented may be a linear hydrocarbon group or a hydrocarbon group having a branched chain and / or a ring structure.

[0138] In formula (C3), R 31 ~R 34 Specific examples of the hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in formula (A) 2 ~R 4 The same applies to specific examples of the hydrocarbon group having 1 to 6 carbon atoms.

[0139] In formula (C3), R 31 ~R 34 The hydrocarbon group having 1 to 6 carbon atoms represented by is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.

[0140] In formula (C3), R 31 ~R 34 The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0141] In formula (C3), R 31 ~R 34 The halogenated hydrocarbon group having 1 to 6 carbon atoms represented by means of a hydrocarbon group having 1 to 6 carbon atoms substituted with at least one halogen atom.

[0142] The halogen atom in the halogenated hydrocarbon group is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom, a chlorine atom or a bromine atom, further preferably a fluorine atom or a chlorine atom, and further preferably a fluorine atom.

[0143] In formula (C3), R 31 ~R 34 The halogenated hydrocarbon group having 1 to 6 carbon atoms represented may be a linear halogenated hydrocarbon group or a halogenated hydrocarbon group having a branched chain and / or a ring structure.

[0144] In formula (C3), R 31 ~R 34 The halogenated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably a halogenated alkyl group, a halogenated alkenyl group, or a halogenated alkynyl group, more preferably a halogenated alkyl group or a halogenated alkenyl group, and particularly preferably a halogenated alkyl group.

[0145] In formula (C3), R 31 ~R 34 The number of carbon atoms in the halogenated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0146] In formula (C3), R 31 ~R 34 The hydrocarbyloxy group having 1 to 6 carbon atoms may be a linear hydrocarbyloxy group or a hydrocarbyloxy group having a branched chain and / or a ring structure.

[0147] In formula (C3), R 31 ~R 34 The hydrocarbonoxy group having 1 to 6 carbon atoms represented by is preferably an alkoxy group, an alkenyloxy group, or an alkynyloxy group, more preferably an alkoxy group or an alkenyloxy group, and particularly preferably an alkoxy group.

[0148] In formula (C3), R 31 ~R 34 The number of carbon atoms in the hydrocarbonoxy group having 1 to 6 carbon atoms is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0149] In formula (C3), R 31 ~R 34 The halogenated hydrocarbyloxy group having 1 to 6 carbon atoms means a hydrocarbyloxy group having 1 to 6 carbon atoms substituted with at least one halogen atom.

[0150] The halogen atom in the halohydrocarbyloxy group is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom, a chlorine atom or a bromine atom, further preferably a fluorine atom or a chlorine atom, and further preferably a fluorine atom.

[0151] In formula (C3), R31 ~R 34 The halogenated hydrocarbonoxy group having 1 to 6 carbon atoms may be a linear halogenated hydrocarbonoxy group or a halogenated hydrocarbonoxy group having a branched chain and / or a ring structure.

[0152] In formula (C3), R 31 ~R 34 The halogenated hydrocarbonoxy group having 1 to 6 carbon atoms is preferably a halogenated alkoxy group, a halogenated alkenyloxy group or a halogenated alkynyloxy group, more preferably a halogenated alkoxy group or a halogenated alkenyloxy group, and particularly preferably a halogenated alkoxy group.

[0153] In formula (C3), R 31 ~R 34 The number of carbon atoms in the halogenated hydrocarbonoxy group having 1 to 6 carbon atoms is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0154] In formula (C3), R 31 ~R 34 , each independently preferably is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, an ethyl group, a vinyl group, an ethynyl group, an allyl group, a trifluoromethyl group, or a methoxy group, and more preferably a hydrogen atom.

[0155] Specific examples of the compound represented by formula (C3) include:

[0156] Sulfobenzoic anhydride,

[0157] Fluorosulfonylbenzoic anhydride,

[0158] Chlorobenzoic anhydride,

[0159] Difluorosulfonylbenzoic anhydride,

[0160] Dichlorosulfonylbenzoic anhydride,

[0161] Trifluorosulfonylbenzoic anhydride,

[0162] Tetrafluorosulfonylbenzoic anhydride,

[0163] Methylsulfonylbenzoic anhydride,

[0164] Dimethylsulfonylbenzoic anhydride,

[0165] Trimethylsulfonylbenzoic anhydride,

[0166] Ethylsulfonylbenzoic anhydride,

[0167] Propylsulfobenzoic anhydride,

[0168] Vinylsulfobenzoic anhydride,

[0169] Ethylenesulfobenzoic anhydride,

[0170] Allyl sulfobenzoic anhydride,

[0171] (Trifluoromethyl)sulfonylbenzoic anhydride,

[0172] Bis(trifluoro)(methyl)sulfonylbenzoic anhydride,

[0173] (Trifluoromethoxy)sulfobenzoic anhydride,

[0174] (Fluoro)(methyl)sulfonylbenzoic anhydride,

[0175] (Chloro)(methyl)sulfonylbenzoic anhydride,

[0176] (Fluoro)(methoxy)sulfobenzoic anhydride,

[0177] (Chloro)(methoxy)sulfobenzoic anhydride,

[0178] Di(fluoro)(methoxy)sulfobenzoic anhydride,

[0179] Bis(trifluoro)(vinyl)sulfonylbenzoic anhydride,

[0180] (Fluoro)(vinyl)sulfobenzoic anhydride,

[0181] Bis(trifluoro)(ethynyl)sulfobenzoic anhydride,

[0182] (Fluoro)(ethynyl)sulfobenzoic anhydride, etc.

[0183] Among these, sulfobenzoic anhydride (hereinafter also referred to as "compound (C3-1)") is particularly preferred.

[0184] (Compound represented by formula (C4))

[0185] The compound represented by formula (C4) is shown below.

[0186] [Chemical formula 10]

[0187]

[0188] In formula (C4), R 41 It represents a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0189] In formula (C4), R 41 The hydrocarbon group having 1 to 6 carbon atoms represented may be a linear hydrocarbon group or a hydrocarbon group having a branched chain and / or a ring structure.

[0190] In formula (C4), R 41 Specific examples of the hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in formula (A) 2 ~R 4The same applies to specific examples of the hydrocarbon group having 1 to 6 carbon atoms.

[0191] In formula (C4), R 41 The hydrocarbon group having 1 to 6 carbon atoms represented by is preferably an alkyl group, an alkenyl group, an alkynyl group, or a phenyl group, more preferably an alkyl group, an alkenyl group, or an alkynyl group, further preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.

[0192] In formula (C4), R 41 The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0193] In formula (C4), R 41 The hydrocarbyloxy group having 1 to 6 carbon atoms may be a linear hydrocarbyloxy group or a hydrocarbyloxy group having a branched chain and / or a ring structure.

[0194] In formula (C4), R 41 The hydrocarbonoxy group having 1 to 6 carbon atoms represented by is preferably an alkoxy group, an alkenyloxy group, or an alkynyloxy group, more preferably an alkoxy group or an alkenyloxy group, and particularly preferably an alkoxy group.

[0195] In formula (C4), R 41 The number of carbon atoms in the hydrocarbonoxy group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0196] In formula (C4), R 41 The fluorinated hydrocarbon group having 1 to 6 carbon atoms may be a linear fluorinated hydrocarbon group or a fluorinated hydrocarbon group having a branched chain and / or a ring structure.

[0197] In formula (C4), R 41 Specific examples of the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in the formula (A) 2 ~R 4 The specific examples of the fluorinated hydrocarbon group having 1 to 6 carbon atoms are the same as those shown in FIG.

[0198] In formula (C4), R 41 The fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably a fluorinated alkyl group, a fluorinated alkenyl group, or a fluorinated alkynyl group, more preferably a fluorinated alkyl group or a fluorinated alkenyl group, and particularly preferably a fluorinated alkyl group.

[0199] In formula (C4), R 41 The number of carbon atoms in the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0200] In formula (C4), R 41, preferably a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, more preferably a fluorine atom, a methyl group, an ethyl group, a trifluoromethyl group, or a pentafluoroethyl group, and particularly preferably a methyl group.

[0201] As a compound represented by formula (C4),

[0202] Preferably, methanesulfonyl fluoride, ethanesulfonyl fluoride, propanesulfonyl fluoride, 2-propanesulfonyl fluoride, butanesulfonyl fluoride, 2-butanesulfonyl fluoride, hexanesulfonyl fluoride, trifluoromethanesulfonyl fluoride, perfluoroethanesulfonyl fluoride, perfluoropropanesulfonyl fluoride, perfluorobutanesulfonyl fluoride, ethylenesulfonyl fluoride, 1-propylene-1-sulfonyl fluoride, or 2-propylene-1-sulfonyl fluoride,

[0203] More preferably, methanesulfonyl fluoride, ethanesulfonyl fluoride, propanesulfonyl fluoride, 2-propanesulfonyl fluoride, butanesulfonyl fluoride, 2-butanesulfonyl fluoride, hexanesulfonyl fluoride, trifluoromethanesulfonyl fluoride, perfluoroethanesulfonyl fluoride, perfluoropropanesulfonyl fluoride, or perfluorobutanesulfonyl fluoride,

[0204] More preferably, methanesulfonyl fluoride, ethanesulfonyl fluoride, propanesulfonyl fluoride, 2-propanesulfonyl fluoride, butanesulfonyl fluoride, 2-butanesulfonyl fluoride, or hexanesulfonyl fluoride is used.

[0205] More preferably, methanesulfonyl fluoride, ethanesulfonyl fluoride, or propanesulfonyl fluoride,

[0206] Methanesulfonyl fluoride is particularly preferred.

[0207] (Compound represented by formula (C5))

[0208] The compound represented by formula (C5) is shown below.

[0209] [Chemical formula 11]

[0210]

[0211] In formula (C5), R 51 It represents a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0212] In formula (C5), R 51 The fluorinated hydrocarbon group having 1 to 6 carbon atoms may be a linear fluorinated hydrocarbon group or a fluorinated hydrocarbon group having a branched chain and / or a ring structure.

[0213] In formula (C5), R 51 Specific examples of the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in the formula (A) 2 ~R 4 The specific examples of the fluorinated hydrocarbon group having 1 to 6 carbon atoms are the same as those shown in FIG.

[0214] In formula (C5), as R 51The fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably a fluorinated alkyl group, a fluorinated alkenyl group, or a fluorinated alkynyl group, more preferably a fluorinated alkyl group or a fluorinated alkenyl group, and particularly preferably a fluorinated alkyl group.

[0215] In formula (C5), as R 51 The number of carbon atoms in the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0216] In formula (C5), R 51 The hydrocarbon group having 1 to 6 carbon atoms represented may be a linear hydrocarbon group or a hydrocarbon group having a branched chain and / or a ring structure.

[0217] In formula (C5), R 51 Specific examples of the hydrocarbon group having 1 to 6 carbon atoms represented by are the same as R in formula (A) 2 ~R 4 The same applies to specific examples of the hydrocarbon group having 1 to 6 carbon atoms.

[0218] In formula (C5), as R 51 The hydrocarbon group having 1 to 6 carbon atoms represented by is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.

[0219] In formula (C5), as R 51 The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0220] In formula (C5), R 51 The hydrocarbyloxy group having 1 to 6 carbon atoms may be a linear hydrocarbyloxy group or a hydrocarbyloxy group having a branched chain and / or a ring structure.

[0221] In formula (C5), as R 51 The hydrocarbonoxy group having 1 to 6 carbon atoms represented by is preferably an alkoxy group, an alkenyloxy group, or an alkynyloxy group, more preferably an alkoxy group or an alkenyloxy group, and particularly preferably an alkoxy group.

[0222] In formula (C5), as R 51 The number of carbon atoms in the hydrocarbonoxy group having 1 to 6 carbon atoms represented by is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0223] In formula (C5), as R 51 , preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

[0224] As a compound represented by formula (C5),

[0225] Preferably lithium trifluoromethanesulfonate or lithium pentafluoroethanesulfonate,

[0226] Lithium trifluoromethanesulfonate is particularly preferred.

[0227] In addition, as the compound represented by formula (C5), compounds represented by the following formula (C5-1) to the following formula (C5-4) (hereinafter, also referred to as compound (C5-1) to compound (C5-4) respectively) are also preferred.

[0228] [Chemical formula 12]

[0229]

[0230] Relative to the total amount of the non-aqueous electrolyte, the content of additive C is preferably 0.001 mass % to 10 mass %, more preferably 0.001 mass % to 5.0 mass %, further preferably 0.001 mass % to 3.0 mass %, further preferably 0.01 mass % to 3.0 mass %, further preferably 0.1 mass % to 3.0 mass %, further preferably 0.1 mass % to 2.0 mass %, further preferably 0.1 mass % to 1.0 mass %, further preferably 0.2 mass % to 0.8 mass %.

[0231] From the viewpoint of more effectively obtaining the effect of reducing the battery resistance after storage, the total content of additive B and additive C is preferably 0.01% by mass to 10% by mass, more preferably 0.1% by mass to 5.0% by mass, further preferably 0.5% by mass to 3.0% by mass, and further preferably 1.0% by mass to 2.0% by mass, relative to the total amount of the non-aqueous electrolyte.

[0232] From the viewpoint of more effectively obtaining the effect of reducing the battery resistance after storage, the ratio of the total mass of additives B and additives C to the mass of additive A (i.e., mass ratio [(additive B + additive C) / additive A]) is preferably 0.01 to 3.0, more preferably 0.05 to 3.0, further preferably 0.05 to 2.0, further preferably 0.05 or more and less than 1.0, further preferably 0.1 to 0.9, and further preferably 0.2 to 0.8.

[0233] Next, other components of the non-aqueous electrolyte solution are described. The non-aqueous electrolyte solution generally contains an electrolyte and a non-aqueous solvent.

[0234] <Non-aqueous solvent>

[0235] The nonaqueous electrolyte of the present disclosure may contain a nonaqueous solvent.

[0236] The non-aqueous solvent that may be contained in the non-aqueous electrolyte may be only one kind or two or more kinds.

[0237] As the nonaqueous solvent, various known nonaqueous solvents can be appropriately selected.

[0238] As the nonaqueous solvent, for example, the nonaqueous solvents described in paragraphs 0069 to 0087 of JP-A-2017-45723 can be used.

[0239] The nonaqueous solvent preferably contains a cyclic carbonate compound and a chain carbonate compound.

[0240] In this case, the cyclic carbonate compound and the chain carbonate compound contained in the non-aqueous solvent may be only one kind or two or more kinds.

[0241] Examples of the cyclic carbonate compound include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, and 2,3-pentylene carbonate.

[0242] Among these, ethylene carbonate and propylene carbonate having high dielectric constants are preferred. In the case of a battery using a negative electrode active material containing graphite, the nonaqueous solvent more preferably contains ethylene carbonate.

[0243] Examples of the chain carbonate compound include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl propyl carbonate, dipropyl carbonate, methyl butyl carbonate, ethyl butyl carbonate, dibutyl carbonate, methyl pentyl carbonate, ethyl pentyl carbonate, dipentyl carbonate, methyl heptyl carbonate, ethyl heptyl carbonate, diheptyl carbonate, methyl hexyl carbonate, ethyl hexyl carbonate, dihexyl carbonate, methyl octyl carbonate, ethyl octyl carbonate, and dioctyl carbonate.

[0244] Specific examples of the combination of cyclic carbonate and linear carbonate include ethylene carbonate and dimethyl carbonate, ethylene carbonate and ethyl methyl carbonate, ethylene carbonate and diethyl carbonate, propylene carbonate and dimethyl carbonate, propylene carbonate and ethyl methyl carbonate, propylene carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate and ethyl methyl carbonate, ethylene carbonate and propylene carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate and Dimethyl carbonate and diethyl carbonate, ethylene carbonate with ethyl methyl carbonate and diethyl carbonate, ethylene carbonate with dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate with dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate and propylene carbonate with dimethyl carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate with ethyl methyl carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate with dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate, etc.

[0245] The mixing ratio of the cyclic carbonate compound and the linear carbonate compound is expressed by mass ratio, and the cyclic carbonate compound: linear carbonate compound is, for example, 5:95 to 80:20, preferably 10:90 to 70:30, and more preferably 15:85 to 55:45. By forming such a ratio, the viscosity rise of the non-aqueous electrolyte can be suppressed, the dissociation degree of the electrolyte can be increased, and therefore, the conductivity of the non-aqueous electrolyte related to the charge and discharge characteristics of the battery can be increased. In addition, the solubility of the electrolyte can be further increased. Therefore, a non-aqueous electrolyte with excellent conductivity at room temperature or low temperature can be formed, and therefore, the load characteristics of the battery at room temperature to low temperature can be improved.

[0246] The nonaqueous solvent may contain other compounds besides the cyclic carbonate compound and the chain carbonate compound.

[0247] In this case, the other compound contained in the non-aqueous solvent may be only one kind or two or more kinds.

[0248] Examples of other compounds include cyclic carboxylate compounds (e.g., γ-butyrolactone), cyclic sulfone compounds, cyclic ether compounds, chain carboxylate compounds, chain ether compounds, chain phosphate compounds, amide compounds, chain carbamate compounds, cyclic amide compounds, cyclic urea compounds, boron compounds, and polyethylene glycol derivatives.

[0249] Regarding these compounds, the description in paragraphs 0069 to 0087 of JP-A-2017-45723 may be appropriately referred to.

[0250] The proportion of the cyclic carbonate compound and the chain carbonate compound in the non-aqueous solvent is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0251] The proportion of the cyclic carbonate compound and the chain carbonate compound in the non-aqueous solvent may be 100% by mass.

[0252] The proportion of the nonaqueous solvent in the nonaqueous electrolyte is preferably 60% by mass or more, more preferably 70% by mass or more.

[0253] The upper limit of the proportion of the nonaqueous solvent in the nonaqueous electrolyte solution depends on the contents of other components (additives A to C, electrolyte, etc.), but is, for example, 99 mass %, preferably 97 mass %, and more preferably 90 mass %.

[0254] <Electrolytes>

[0255] The nonaqueous electrolyte of the present disclosure may contain an electrolyte.

[0256] The electrolyte preferably comprises LiPF 6 .

[0257] In this case, LiPF 6 The ratio of the polyol in the electrolyte is preferably 1% by mass to 100% by mass, more preferably 10% by mass to 100% by mass, and further preferably 50% by mass to 100% by mass.

[0258] The concentration of the electrolyte in the non-aqueous electrolyte of the present disclosure is preferably 0.1 mol / L to 3 mol / L, more preferably 0.5 mol / L to 2 mol / L.

[0259] In addition, LiPF in the non-aqueous electrolyte of the present disclosure 6 The concentration is preferably 0.1 mol / L to 3 mol / L, more preferably 0.5 mol / L to 2 mol / L.

[0260] The electrolyte may contain LiPF 6 Other compounds.

[0261] As LiPF 6 Other compounds include:

[0262] (C 2 H 5 ) 4 NPF 6 , (C 2 H 5 ) 4 NBF 4 , (C 2 H 5 ) 4 NClO 4 , (C 2 H 5 ) 4 NAS 6 , (C 2 H 5 ) 4 N 2 SiF 6 , (C 2 H 5 ) 4 NOSO 2 C k F (2k+1) (k=integer from 1 to 8), (C 2 H 5 ) 4 NPF n [C k F (2k+1) ] (6-n) (n=1-5, k=1-8 integer) and other tetraalkylammonium salts;

[0263] LiBF4 、LiClO 4 、LiAsF 6 , Li 2 SiF 6 、LiOSO 2 C k F (2k+1) (k=integer of 1 to 8), LiPF n [C k F (2k+1) ] (6-n) (n=1 to 5, k=integer of 1 to 8), LiC(SO 2 R 7 )(SO 2 R 8 )(SO 2 R 9 )、LiN(SO 2 OR 10 )(SO 2 OR 11 )、LiN(SO 2 R 12 )(SO 2 R 13 )(Here, R 7 ~R 13 They may be the same or different and are fluorine atoms or perfluoroalkyl groups having 1 to 8 carbon atoms) and other lithium salts (i.e., LiPF 6 Lithium salts other than lithium salts); etc.

[0264] <Application>

[0265] The nonaqueous electrolyte of the present disclosure can be used as an electrolyte for batteries.

[0266] The nonaqueous electrolyte of the present disclosure can be used, for example, in a battery containing a negative electrode active material including a graphite material.

[0267] Generally, for a battery containing a non-aqueous electrolyte including an additive A such as FEC and a negative electrode active material including a graphite material, the battery resistance tends to increase due to reductive decomposition of the additive A on the graphite material and oxidative decomposition of the reductive decomposition product on the positive electrode.

[0268] However, since the nonaqueous electrolyte of the present disclosure contains not only the additive A but also the additive B and the additive C, the battery resistance after storage can be suppressed even when used in a battery containing a negative electrode active material containing a graphite material.

[0269] That is, when the nonaqueous electrolyte of the present disclosure is used in a battery containing a negative electrode active material including a graphite material, the improvement (specifically, the reduction in battery resistance after storage) brought about by the nonaqueous electrolyte of the present disclosure is large.

[0270] The negative electrode active material containing the graphite material may further contain silicon oxide (hereinafter also referred to as "SiO X ”).

[0271] That is, the non-aqueous electrolyte of the present disclosure can be used to contain a graphite material and SiO X A battery having a negative electrode active material.

[0272] SiO X …Composition formula (1)

[0273] [In the composition formula (1), X represents 0.5 or more and less than 1.6.]

[0274] Typically, graphite materials and SiO X The battery capacity of the battery containing the negative electrode active material is excellent. However, for the battery containing the graphite material and SiO X For negative electrode active materials, the expansion and contraction amplitude during cycling is large, so there may be problems with the cycle characteristics.

[0275] In this regard, it is considered that the additive A contained in the non-aqueous electrolyte of the present disclosure is contained in SiO X is reduced and decomposed, thereby X LiF and a film having excellent mechanical flexibility are formed on the surface of the battery. The deterioration of the cycle characteristics of the battery can be suppressed by the LiF and the film.

[0276] Therefore, it is believed that the non-aqueous electrolyte of the present disclosure is used to contain a graphite material and SiO X In the case of a battery with a negative electrode active material, the effect of additive A can inhibit the X This results in degradation of the battery's cycle characteristics.

[0277] Furthermore, as described above, the battery resistance after storage can be suppressed by the combined action of the additives A to C.

[0278] Preferred embodiments of the negative electrode active material will be described later.

[0279] 〔Lithium secondary battery〕

[0280] The lithium secondary battery of the present disclosure includes a positive electrode, a negative electrode, and the nonaqueous electrolyte of the present disclosure.

[0281] Therefore, the lithium secondary battery of the present disclosure is excellent in battery resistance after storage (that is, the battery resistance after storage can be reduced).

[0282] <Negative electrode>

[0283] The negative electrode contains a negative electrode active material including a graphite material.

[0284] Examples of the graphite material include natural graphite and artificial graphite.

[0285] The negative electrode active material may contain only one type of graphite material, or may contain two or more types of graphite materials.

[0286] The graphite material preferably includes natural graphite, and more preferably includes natural graphite coated with amorphous carbon (hereinafter also referred to as “amorphous-coated natural graphite”).

[0287] When the graphite material contains natural graphite, the proportion of natural graphite in the graphite material is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0288] The ratio of amorphous carbon in the amorphous carbon-coated natural graphite is preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, and even more preferably 0.3 to 3% by mass.

[0289] As the graphite material, a graphite material having a (002) plane spacing d(002) of 0.340 nm or less as measured by X-ray analysis is particularly preferred.

[0290] In addition, the true density of the graphite material is preferably 1.70 g / cm 3 above.

[0291] When the negative electrode active material contains a graphite material, the content of the graphite material relative to the total amount of the negative electrode active material is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 92% by mass or more.

[0292] The negative electrode active material including the graphite material may further include SiO X , that is, silicon oxide represented by the following composition formula (1).

[0293] SiO X …Composition formula (1)

[0294] [In the composition formula (1), X represents 0.5 or more and less than 1.6.]

[0295] SiO X Can be coated with amorphous carbon.

[0296] About SiO X, you can appropriately refer to known documents such as International Publication No. 2013 / 094668 and Japanese Patent Publication No. 2016-143642.

[0297] The negative electrode active material includes graphite material and SiO X In the case of SiO X The content of 1% by mass to 20% by mass is preferably 1% by mass to 10% by mass, more preferably 2% by mass to 8% by mass.

[0298] The negative electrode active material includes graphite material and SiO X In this case, the content of the graphite material relative to the total amount of the negative electrode active material is preferably 80% by mass to 99% by mass, more preferably 90% by mass to 99% by mass, and even more preferably 92% by mass to 98% by mass.

[0299] The negative electrode active material may contain other components besides the above.

[0300] Examples of other components include carbon materials other than graphite materials (for example, carbon black, activated carbon, amorphous carbon materials, etc.); metals or alloys such as silicon, silicon alloys, tin, and tin alloys; lithium titanate; and the like.

[0301] Examples of the amorphous carbon material include hard carbon, coke, mesocarbon microbeads (MCMB) sintered at 1500° C. or lower, and mesophase pitch carbon fibers (MCF).

[0302] In addition, as the negative electrode active material, natural graphite coated with an amorphous carbon material; natural graphite coated with a metal such as gold, platinum, silver, copper, tin, etc. can be used.

[0303] The negative electrode may include a negative electrode current collector.

[0304] The material of the negative electrode current collector in the negative electrode is not particularly limited, and any known negative electrode current collector material can be used.

[0305] Specific examples of the negative electrode current collector include metal materials such as copper, nickel, stainless steel, and nickel-plated steel. Among them, copper is particularly preferred from the viewpoint of ease of processing.

[0306] <Positive electrode>

[0307] The positive electrode may include a positive electrode active material and a positive electrode current collector.

[0308] Examples of the positive electrode active material in the positive electrode include MoS 2 、TiS 2 、MnO 2 、V 2 O 5Transition metal oxides or transition metal sulfides, LiCoO 2 、LiMnO 2 、LiMn 2 O 4 、LiNiO 2 、LiNi X Co (1-X) O 2 〔0<X<1〕, with α-NaFeO 2 Li-type crystal structure 1+α Me 1-α O 2 (Me is a transition metal element including Mn, Ni and Co, 1.0≤(1+α) / (1-α)≤1.6), LiNi x Co y Mn z O 2 [x+y+z=1, 0<x<1, 0<y<1, 0<z<1] (for example, LiNi 0.33 Co 0.33 Mn 0.33 O 2 、LiNi 0.5 Co 0.2 Mn 0.3 O 2 etc.), LiFePO 4 、LiMnPO 4 Conductive polymer materials such as composite oxides formed by lithium and transition metals, polyaniline, polythiophene, polypyrrole, polyacetylene, polybenzone, dithiothiadiazole, polyaniline complex, etc. are preferably used. Among these, composite oxides formed by lithium and transition metals are particularly preferred. When the negative electrode is lithium metal or lithium alloy, carbon materials can also be used as the positive electrode. In addition, composite oxides of lithium and transition metals and mixtures of carbon materials can also be used as the positive electrode.

[0309] The positive electrode active material may be used alone or in combination of two or more. When the conductivity of the positive electrode active material is insufficient, it may be used together with a conductive auxiliary agent to form the positive electrode. Examples of the conductive auxiliary agent include carbon materials such as carbon black, amorphous whiskers, and graphite.

[0310] The material of the positive electrode current collector in the positive electrode is not particularly limited, and any known positive electrode current collector material can be used.

[0311] Specific examples of the positive electrode current collector include metal materials such as aluminum, aluminum alloys, stainless steel, nickel, titanium, and tantalum; and carbon materials such as carbon cloth and carbon paper.

[0312] <Diaphragm>

[0313] The lithium secondary battery of the present disclosure preferably includes a separator between the negative electrode and the positive electrode.

[0314] The separator is a membrane that electrically insulates the positive electrode from the negative electrode and allows lithium ions to pass therethrough, and examples thereof include porous membranes and polymer electrolytes.

[0315] As the porous film, a microporous polymer film can be preferably used, and examples of the material thereof include polyolefin, polyimide, polyvinylidene fluoride and polyester.

[0316] In particular, porous polyolefins are preferred, and specific examples thereof include porous polyethylene films, porous polypropylene films, or multilayer films of porous polyethylene films and polypropylene films. Other resins having excellent thermal stability may be coated on the porous polyolefin film.

[0317] Examples of the polymer electrolyte include a polymer in which a lithium salt is dissolved and a polymer swollen with an electrolytic solution.

[0318] The nonaqueous electrolyte solution of the present disclosure can be used for the purpose of swelling a polymer to obtain a polymer electrolyte.

[0319] <Battery Structure>

[0320] The lithium secondary battery of the present disclosure can adopt various known shapes, and can be formed into a cylindrical, button-shaped, angular, laminated, film-shaped, or any other shape. However, regardless of the shape, the basic structure of the battery is the same, and the design can be changed according to the purpose.

[0321] As an example of the lithium secondary battery of the present disclosure, a laminated type battery can be mentioned.

[0322] Figure 1 1 is a schematic perspective view showing an example of a laminated battery as an example of a lithium secondary battery of the present disclosure. Figure 2 To be contained in Figure 1 A schematic cross-sectional view in the thickness direction of a stacked electrode body in a laminated battery is shown.

[0323] Figure 1 The laminated battery shown in the figure comprises a laminated external package 1, in which a non-aqueous electrolyte ( Figure 1 not shown) and a stacked electrode body ( Figure 1 (not shown in the figure), and the periphery is sealed to seal the interior. As the laminated external package 1, for example, a laminated external package made of aluminum can be used.

[0324] For the stacked electrode body housed in the laminated external package 1, Figure 2As shown, there is a stacked body formed by alternately stacking positive electrode plates 5 and negative electrode plates 6 with separators 7 interposed therebetween, and a separator 8 surrounding the stacked body. The positive electrode plates 5, negative electrode plates 6, separators 7, and separators 8 are impregnated with the nonaqueous electrolyte of the present disclosure.

[0325] The plurality of positive electrode plates 5 in the stacked electrode assembly are all electrically connected to the positive electrode terminal 2 via the positive electrode tab (not shown), and a portion of the positive electrode terminal 2 protrudes outward from the peripheral end of the laminated external package 1 ( Figure 1 ). At the peripheral end of the laminated external package 1 , the protruding portion of the positive electrode terminal 2 is sealed by an insulating sealing body 4 .

[0326] Similarly, the plurality of negative electrode plates 6 in the stacked electrode assembly are electrically connected to the negative electrode terminal 3 via the negative electrode tab (not shown), and a portion of the negative electrode terminal 3 protrudes outward from the peripheral end of the laminated external package 1 ( Figure 1 ). At the peripheral end of the laminated external package 1 , the protruding portion of the negative electrode terminal 3 is sealed by an insulating sealing body 4 .

[0327] It should be noted that, in the laminated battery involved in the above example, the number of positive plates 5 is 5, the number of negative plates 6 is 6, and the positive plates 5 and the negative plates 6 are stacked with the separator 7 between them, with the outermost layers on both sides being the negative plates 6. However, it goes without saying that the number of positive plates, the number of negative plates, and the arrangement in the laminated battery are not limited to the above example, and various changes can be made.

[0328] Another example of the lithium secondary battery of the present disclosure is a button-type battery.

[0329] Figure 3 This is a schematic perspective view showing an example of a button-type battery which is another example of the lithium secondary battery of the present disclosure.

[0330] for Figure 3 For the button-type battery shown, a disc-shaped negative electrode 12, a separator 15 injected with a non-aqueous electrolyte, a disc-shaped positive electrode 11, and spacers 17 and 18 made of stainless steel or aluminum as required are stacked in this order and are housed between a positive electrode case 13 (hereinafter, also referred to as a "battery case") and a sealing plate 14 (hereinafter, also referred to as a "battery case cover"). The positive electrode case 13 and the sealing plate 14 are sealed by caulking with a gasket 16 therebetween.

[0331] In the above example, as the nonaqueous electrolyte solution injected into the separator 15 , the nonaqueous electrolyte solution of the present disclosure is used.

[0332] The lithium secondary battery of the present disclosure may be a lithium secondary battery obtained by charging and discharging a lithium secondary battery (lithium secondary battery before charging and discharging) including a negative electrode, a positive electrode, and the above-mentioned nonaqueous electrolyte of the present disclosure.

[0333] That is, the lithium secondary battery of the present disclosure can be a lithium secondary battery (a lithium secondary battery that has been charged and discharged) manufactured in the following manner: first, a lithium secondary battery before charge and discharge is manufactured, which includes a negative electrode, a positive electrode, and the non-aqueous electrolyte of the present disclosure, and then, the lithium secondary battery before charge and discharge is charged and discharged more than once.

[0334] The use of the lithium secondary battery of the present disclosure is not particularly limited and can be used for various known uses. For example, it can be widely used in small portable devices or large devices such as notebook computers, mobile computers, mobile phones, stereo headphones, video movie players, LCD TVs, handheld vacuum cleaners, electronic notebooks, calculators, radios, backup power uses, motors, cars, electric cars, motorcycles, electric motorcycles, bicycles, electric bicycles, lighting fixtures, game consoles, clocks, power tools, cameras, etc.

[0335] Example

[0336] Hereinafter, examples of the present disclosure will be described, but the present disclosure is not limited to the following examples.

[0337] Hereinafter, "amount added" means the content relative to the total amount of the non-aqueous electrolyte solution finally obtained, and "wt%" means mass %.

[0338] [Example 1]

[0339] A button-type battery (test battery) as a lithium secondary battery was produced according to the following procedure.

[0340] <Production of negative electrode>

[0341] Amorphous coated natural graphite (92 parts by mass), SiO (i.e., silicon oxide in which X in the composition formula (1) is 1; manufactured by Osaka Titanium Technologies Co., Ltd.) (5 parts by mass), carboxymethyl cellulose (1 part by mass) and SBR latex (2 parts by mass) were kneaded with an aqueous solvent to prepare a paste-like negative electrode mixture slurry.

[0342] Next, the negative electrode mixture slurry was applied to a negative electrode current collector made of a strip of copper foil with a thickness of 10 μm and dried, and then compressed using a roller press to obtain a sheet-shaped negative electrode consisting of the negative electrode current collector and the negative electrode active material layer. The coating density of the negative electrode active material layer at this time was 12 mg / cm 2 , the filling density is 1.5g / mL.

[0343] Here, the amorphous coated natural graphite is natural graphite coated with amorphous carbon.

[0344] The ratio of natural graphite in the amorphous coated natural graphite was 99% by mass, and the ratio of amorphous carbon in the amorphous coated natural graphite was 1% by mass.

[0345] <Production of positive electrode>

[0346] LiNi was prepared by using N-methylpyrrolidone as solvent. 0.5 Mn 0.3 Co 0.2 O 2 (90 parts by mass), acetylene black (5 parts by mass) and polyvinylidene fluoride (5 parts by mass) were mixed and kneaded to prepare a positive electrode mixture slurry in a paste form.

[0347] Next, the positive electrode mixture slurry was applied to a positive electrode current collector of a 20 μm thick strip of aluminum foil and dried, and then compressed using a roller press to obtain a sheet-shaped positive electrode consisting of the positive electrode current collector and the positive electrode active material layer. The coating density of the positive electrode active material layer at this time was 22 mg / cm 2 , the filling density is 2.5g / mL.

[0348] <Preparation of non-aqueous electrolyte>

[0349] Ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) as non-aqueous solvents were mixed in a ratio of 30:35:35 (mass ratio) to obtain a mixed solvent.

[0350] The LiPF in the final non-aqueous electrolyte 6 The concentration of LiPF was 1.0 mol / L. 6 Dissolve in the obtained mixed solvent.

[0351] To the solution obtained above, the following substances are added to obtain a non-aqueous electrolyte:

[0352] 4-Fluoroethylene carbonate (FEC) as additive A (addition amount: 3.0 mass %),

[0353] Lithium difluorophosphate (LiDFP) as additive B (added in an amount of 1.0 mass %), and

[0354] The following compound (C1-1) (a specific example of the compound represented by the formula (C1)) was used as the additive C (the amount added was 0.5% by mass).

[0355] [Chemical formula 13]

[0356]

[0357] <Production of button-type batteries>

[0358] Separately, the negative electrode was punched into a disc shape with a diameter of 14 mm, and the positive electrode was punched into a disc shape with a diameter of 13 mm to obtain a button-shaped negative electrode and a button-shaped positive electrode, respectively. In addition, a microporous polyethylene film with a thickness of 20 μm was punched into a disc shape with a diameter of 17 mm to obtain a separator.

[0359] The obtained button-shaped negative electrode, separator, and button-shaped positive electrode were stacked in this order in a stainless steel battery case (2032 size), and then 20 μL of a nonaqueous electrolyte was injected into the battery case to impregnate the separator, positive electrode, and negative electrode.

[0360] Next, an aluminum plate (1.2 mm thick, 16 mm in diameter) and a spring were placed on the positive electrode, and the battery case cover was caulked via a polypropylene gasket to seal the battery.

[0361] Through the above method, a 20 mm diameter and 3.2 mm height Figure 3 A button-type battery (ie, a button-type lithium secondary battery) having a structure shown.

[0362] <Evaluation of battery resistance>

[0363] The obtained button-type batteries were subjected to conditioning and aging in sequence, and the battery resistance of the aged button-type batteries before and after high-temperature storage was evaluated.

[0364] Here, the term "conditioning" means that the button-type battery is repeatedly charged and discharged three times between 2.75V and 4.2V at 25°C in a thermostatic chamber.

[0365] The term "aging" refers to an operation of storing the conditioned button-type battery at 60° C. for 72 hours in a state of SOC (State of Charge) 100%.

[0366] The state of SOC 100% in the present embodiment corresponds to a state of being charged at a charging voltage of 4.25V.

[0367] The term “high temperature storage” refers to an operation of storing the aged button-type battery at 60° C. for 72 hours in a state of SOC 100%.

[0368] Hereinafter, the battery resistance was measured under two temperature conditions, 25°C and -20°C.

[0369] (Measurement of battery resistance before high-temperature storage)

[0370] The SOC (State of Charge) of the aged button-type battery was adjusted to 80%, and then the battery resistance (DC resistance) of the button-type battery before high-temperature storage was measured by the following method.

[0371] The above-mentioned button-type battery whose SOC has been adjusted to 80% was used to perform CC10s discharge at a discharge rate of 0.2C.

[0372] Here, CC10s discharge refers to discharge at a constant current for 10 seconds.

[0373] Based on the current value in the above-mentioned "CC10s discharge at a discharge rate of 0.2C" (i.e., the current value equivalent to the discharge rate of 0.2C) and the voltage drop (= voltage before the start of discharge - voltage 10 seconds after the start of discharge), the DC resistance is calculated, and the obtained DC resistance (Ω) is used as the battery resistance (Ω) of the button-type battery before high-temperature storage.

[0374] The battery resistance (Ω) before high-temperature storage was similarly measured for the button-type battery of Comparative Example A described later.

[0375] The battery resistance (relative value) of the button-type battery of Example 1 before high-temperature storage was determined, with the battery resistance of the button-type battery of Comparative Example A before high-temperature storage being 100.

[0376] The results are shown in Table 1.

[0377] (Measurement of battery resistance after high temperature storage)

[0378] The button-type battery whose battery resistance was measured before high-temperature storage was CC-CV charged at 25°C and a charging rate of 0.2C until 4.25V, which was a state of SOC of 100%, was then stored at high temperature in this state (i.e., stored at 60°C for 72 hours). Here, CC-CV charging refers to constant current-constant voltage.

[0379] The SOC of the button-type battery after high-temperature storage was adjusted to 80%, and then the battery resistance of the button-type battery after high-temperature storage was measured by the same method as the measurement of the battery resistance before high-temperature storage.

[0380] The battery resistance (Ω) after high-temperature storage was similarly measured for the button-type battery of Comparative Example A described later.

[0381] The battery resistance (relative value) of the button-type battery of Example 1 after high-temperature storage was determined, with the battery resistance of the button-type battery of Comparative Example A after high-temperature storage being 100.

[0382] The results are shown in Table 1.

[0383] [Comparative Example A]

[0384] The same operation as in Example 1 was carried out except that the non-aqueous electrolyte did not contain the additive A, the additive B, and the additive C. The results are shown in Table 1.

[0385] In Table 1, “-” indicates that the corresponding additive is not contained.

[0386] [Comparative Example B]

[0387] The same operation as in Example 1 was carried out except that the non-aqueous electrolyte did not contain the additives B and C. The results are shown in Table 1.

[0388] [Comparative Examples 1 to 3]

[0389] The same operation as in Example 1 was carried out except that the presence or absence of each component in Additives A to C was changed as shown in Table 1. The results are shown in Table 1.

[0390] [Example 101 and Comparative Examples 101 to 103]

[0391] The same operations as in Example 1 and Comparative Examples 1 to 3 were performed except that the type of additive C was changed to PRS (that is, the following compound (C2-1); a specific example of the compound represented by formula (C2)).

[0392] The results are shown in Table 1.

[0393] In these examples, the battery resistance before high-temperature storage is expressed as a relative value with the battery resistance before high-temperature storage in Comparative Example A being 100, and the battery resistance after high-temperature storage is expressed as a relative value with the battery resistance after high-temperature storage in Comparative Example A being 100.

[0394] [Chemical formula 14]

[0395]

[0396] [Example 201 and Comparative Examples 201 to 203]

[0397] The same operations as in Example 1 and Comparative Examples 1 to 3 were carried out except that the type of additive C was changed to the following compound (C1-2) (specific example of the compound represented by formula (C1)).

[0398] The results are shown in Table 1.

[0399] In these examples, the battery resistance before high-temperature storage is expressed as a relative value with the battery resistance before high-temperature storage in Comparative Example A being 100, and the battery resistance after high-temperature storage is expressed as a relative value with the battery resistance after high-temperature storage in Comparative Example A being 100.

[0400] [Chemical formula 15]

[0401]

[0402] [Example 301 and Comparative Examples 301 to 303]

[0403] The same operations as in Example 1 and Comparative Examples 1 to 3 were performed except that the type of additive C was changed to sulfobenzoic anhydride (specifically, the following compound (C3-1); a specific example of the compound represented by formula (C3)).

[0404] The results are shown in Table 1.

[0405] In these examples, the battery resistance before high-temperature storage is expressed as a relative value with the battery resistance before high-temperature storage in Comparative Example A being 100, and the battery resistance after high-temperature storage is expressed as a relative value with the battery resistance after high-temperature storage in Comparative Example A being 100.

[0406] [Chemical formula 16]

[0407]

[0408] [Table 1]

[0409]

[0410] As shown in Table 1, in Comparative Example B containing Additive A but not containing Additives B and C, the battery resistance increased both before and after high-temperature storage, compared with Comparative Example A containing no Additives A to C.

[0411] In Examples 1 and 101 to 103 containing Additives A to C, compared with Comparative Example B, the battery resistance after high-temperature storage was reduced.

[0412] From the series of Example 1 and Comparative Examples 1 to 3, it can be seen that the effect of reducing the battery resistance after high-temperature storage in Example 1 is an effect brought about by the combination of additives A to C.

[0413] Similarly, from the series of Example 101 and Comparative Examples 101 to 103, the series of Example 201 and Comparative Examples 201 to 203, and the series of Example 301 and Comparative Examples 301 to 303, it can be seen that the effect of reducing the battery resistance after high-temperature storage is the effect brought about by the combination of additives A to C.

[0414] The entire contents disclosed in Japanese Patent Application No. 2018-140490 filed on July 26, 2018 are incorporated into this specification by reference.

[0415] All documents, patent applications, and technical standards described in this specification are incorporated into this specification by reference to the same extent as if each document, patent application, and technical standard was specifically and individually described.

Claims

1. A non-aqueous electrolyte for a battery, which is used for a battery containing a negative electrode active material containing a graphite material, comprising: Additive A, wherein the additive A is at least one selected from the group consisting of compounds represented by the following formula (A); An additive B, wherein the additive B is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate; and An additive C, wherein the additive C is at least one selected from the group consisting of compounds having a sulfur-oxygen bond, [Chemical formula 1] In formula (A), R 1 represents a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, R 2 ~R 4 Each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

2. The non-aqueous electrolyte for a battery according to claim 1, wherein The additive C is at least one selected from the group consisting of cyclic sulfate ester compounds, cyclic sulfonate ester compounds, substituted or unsubstituted sulfobenzoic anhydride, fluorosulfonyl compounds, and lithium sulfonate compounds.

3. The non-aqueous electrolyte for a battery according to claim 1, wherein The additive C is at least one selected from the group consisting of a compound represented by the following formula (C1), a compound represented by the following formula (C2), a compound represented by the following formula (C3), a compound represented by the following formula (C4), and a compound represented by the following formula (C5), [Chemical formula 2] In formula (C1), R 11 ~R 14 Each independently represents a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b). In formula (1a) and formula (1b), * represents a bonding position. In formula (C2), R 21 ~R 24 each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, In formula (C3), R 31 ~R 34 each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a halogenated hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a halogenated hydrocarbonoxy group having 1 to 6 carbon atoms, In formula (C4), R 41 represents a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms, In formula (C5), R 51 It represents a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbonoxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

4. The non-aqueous electrolyte for a battery according to claim 1, wherein The content of the graphite material is 80 mass % or more based on the total amount of the negative electrode active material.

5. The non-aqueous electrolyte for a battery according to claim 4, wherein The negative electrode active material further comprises silicon oxide represented by the following composition formula (1): SiO X …Composition formula (1) In the composition formula (1), X represents 0.5 or more and less than 1.

6.

6. The non-aqueous electrolyte for a battery according to any one of claims 1 to 5, wherein The content of the additive A is 0.001 mass % to 20 mass % relative to the total amount of the non-aqueous electrolyte for the battery.

7. The non-aqueous electrolyte for a battery according to any one of claims 1 to 5, wherein The content of the additive B is 0.001 mass % to 10 mass % relative to the total amount of the non-aqueous electrolyte for the battery.

8. The non-aqueous electrolyte for a battery according to any one of claims 1 to 5, wherein The content of the additive C is 0.001 mass % to 10 mass % relative to the total amount of the non-aqueous electrolyte for the battery. 9 . A lithium secondary battery comprising: a positive electrode; a negative electrode containing a negative electrode active material including a graphite material; and the nonaqueous electrolyte for a battery according to claim 1 .

10. The lithium secondary battery according to claim 9, wherein: The content of the graphite material is 80 mass % or more based on the total amount of the negative electrode active material.

11. The lithium secondary battery according to claim 9, wherein: The negative electrode active material further comprises silicon oxide represented by the following composition formula (1): SiO X …Composition formula (1) In the composition formula (1), X represents 0.5 or more and less than 1.

6.

12. A lithium secondary battery obtained by charging and discharging the lithium secondary battery according to claim 9 or 10.

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