Non-aqueous electrolyte battery using a non-aqueous electrolyte

Abstract

To provide a non-aqueous electrolyte for a non-aqueous electrolyte battery that can improve the capacity retention rate after cyclic charging and discharging and suppress electrode swelling and resistance after cycling.SOLUTION: A non-aqueous electrolyte for a non-aqueous electrolyte battery includes a non-aqueous electrolyte, a positive electrode having a positive electrode active material capable of intercalating and releasing metal ions, and a negative electrode having a negative electrode active material that can occlude and release metal ions, and the non-aqueous electrolyte contains a compound (A) represented by the formula (I), and the negative electrode active material contains a material containing a metal element and / or a metalloid element that can be alloyed with Li.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a non-aqueous electrolyte battery using a non-aqueous electrolyte. [Background technology]

[0002] Energy devices, such as lithium-ion secondary batteries and other non-aqueous electrolyte batteries, are being put into practical use in a wide range of applications, from power supplies for so-called consumer electronics such as mobile phones and laptop computers to on-board power supplies for automobiles. However, in recent years, the demand for higher performance in non-aqueous electrolyte batteries has been increasing, and in particular, there is a demand for improvements in various battery characteristics such as higher capacity, low-temperature operation characteristics, high-temperature storage characteristics, cycle characteristics, and overcharge safety. To date, numerous technologies have been investigated regarding the active materials of the positive and negative electrodes, as well as various battery components, including the non-aqueous electrolyte, as means of improving the high-temperature storage characteristics and cycle characteristics of non-aqueous electrolyte secondary batteries.

[0003] As described above, with the increasing demand for higher performance in non-aqueous electrolyte secondary batteries in recent years, there is a need for further improvements in the performance of non-aqueous electrolyte secondary batteries, particularly in both capacity, initial performance, and durability performance such as repeated charge and discharge cycles.

[0004] On the other hand, in response to the recent demand for higher energy density, development using negative electrode active materials that include materials other than carbon materials is attracting attention.

[0005] Patent Document 1 describes an attempt to improve the cycle characteristics of a battery by using a material containing Si and O as constituent elements and a graphite material as the negative electrode active material, and using a halogenated cyclic carbonate or vinylene carbonate as the electrolyte. Patent Document 2 discloses a non-aqueous electrolyte for lithium-ion secondary batteries containing a specific vinylene carbonate compound and a specific vinylethylene sulfite, in order to provide a lithium-ion secondary battery that suppresses gas generation during continuous charging and has excellent discharge characteristics after continuous charging. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-233245 [Patent Document 2] Japanese Patent Publication No. 2005-166553 [Overview of the project] [Problems that the invention aims to solve]

[0007] While the batteries described in Patent Documents 1 and 2 can improve cycle characteristics, there was still room for improvement.

[0008] The present invention was made to solve the above problems and relates to a non-aqueous electrolyte that, when used in a non-aqueous electrolyte battery, can improve the capacity retention rate after cycle charging and discharging, and suppress electrode swelling and resistance after cycling. [Means for solving the problem]

[0009] In view of the above circumstances, the inventors of the present invention conducted diligent studies and found that the above problems can be solved by using a non-aqueous electrolyte for a non-aqueous electrolyte battery having a negative electrode containing a material that contains a metal element and / or a metalloid element that can be alloyed with Li, and which contains a specific cyclic sulfur-containing compound, and thus completed the present invention.

[0010] In other words, the gist of the present invention is as follows: [1] A non-aqueous electrolyte for a non-aqueous electrolyte battery, comprising a negative electrode having a negative electrode active material containing a metallic element and / or a metalloid element that can be alloyed with Li, A non-aqueous electrolyte characterized in that the non-aqueous electrolyte contains compound (A) represented by formula (I). [ka] (In formula (I), X , 2 , , 2 , , 2 , 2 , 1 , , , , 1 , 1 , , 1 and X 2 is each independently an oxygen atom or CH2, and R 1 and R 2 are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and n is 1 or 2. However, either R 1 and R 2 is a hydrocarbon group containing at least one carbon-carbon unsaturated bond. When n is 2, X 1 and X 2 at least one of which is CH2.) [2] The non-aqueous electrolyte according to [1], wherein the compound (A) is a compound represented by the following formula (II). [Chemical formula] (In formula (II), R 1 and R 2 are the same as R 1 and R 2 in the above formula (I).) [3] The non-aqueous electrolyte according to [1] or [2], wherein R 1 and R 2 are each independently one selected from a hydrogen atom, a halogen atom, a vinyl group, and an allyl group, and either R 1 and R 2 is selected from a vinyl group and an allyl group.) [4] Further, one or more anion-containing compounds selected from the group consisting of a phosphate anion-containing compound having a P-F bond and a P=O bond, an anion-containing compound having an S=O bond, and an oxalate complex anion-containing compound are contained in the non-aqueous electrolyte in an amount of 0.001% by mass or more and 5% by mass or less. The non-aqueous electrolyte according to any one of [1] to [3]. [5] The non-aqueous electrolyte according to any one of [1] to [4], wherein the non-aqueous electrolyte contains the compound (A) in an amount of 0.01% by mass or more and 10% by mass or less. [6] A non-aqueous electrolyte battery comprising a non-aqueous electrolyte, a positive electrode having a positive electrode active material, and a negative electrode having a negative electrode active material, The non-aqueous electrolyte is the non-aqueous electrolyte described in any of [1] to [5], A non-aqueous electrolyte battery characterized in that the negative electrode active material contains a material containing a metallic element and / or a metalloid element that can be alloyed with Li. [7] The non-aqueous electrolyte battery according to [6], wherein the negative electrode active material contains the element Si. [Effects of the Invention]

[0011] According to the present invention, a non-aqueous electrolyte can be provided that, when used in a non-aqueous electrolyte battery, improves the capacity retention rate after cycle charging and discharging, and suppresses electrode swelling and resistance after cycling. [Modes for carrying out the invention]

[0012] [1. Non-aqueous electrolyte] The non-aqueous electrolyte of the non-aqueous electrolyte battery of the present invention contains compound (A) represented by formula (I) (hereinafter also referred to as "compound (A)").

[0013] The inventors speculate that the reason why the non-aqueous electrolyte battery having the configuration of the present invention exhibits superior effects is as follows: During charging and discharging of the non-aqueous electrolyte battery, compound (A) containing carbon-carbon unsaturated bonds reacts with the surface of a metal element and / or metalloid element that can alloy with Li contained in the negative electrode active material, forming a protective film on the material containing the element. Furthermore, sulfur atoms are reduced to form an anionic film, which promotes Li conduction in the film and suppresses overvoltage during charging and discharging. For this reason, it is thought that the deterioration of particles in the material containing a metal element and / or metalloid element that can alloy with Li, and the decomposition reaction of the electrolyte on the surface of the particles are suppressed.

[0014] [1-1. Compound (A)]

[0015] [ka]

[0016] In formula (I), X 1 and X2 Each is independently an oxygen atom or CH2, and R 1 and R 2 Each of these is independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and n is 1 or 2. However, R 1 , R 2 Either one of them is a hydrocarbon group containing at least one carbon-carbon unsaturated bond. When n is 2, X 1 and X 2 At least one of them is CH2.

[0017] Among these, X 1 X is an oxygen atom. 2 A sulfite ester structure where is an oxygen atom and n is 1; X 1 X is an oxygen atom. 2 Preferably, the structure is a sulfonic acid ester structure where is CH2 and n is 2; X 1 X is an oxygen atom. 2 A sulfite ester structure in which is an oxygen atom and n is 1 is more preferable.

[0018] R 1 and R 2 Either one of these is a hydrocarbon group containing at least one carbon-carbon unsaturated bond. Examples of hydrocarbon groups containing at least one carbon-carbon unsaturated bond include C2-C8 alkenyl groups, C2-C8 alkynyl groups, C4-C12 aryl groups, or C7-C10 aralkyl groups, with C2-C8 alkenyl groups or C2-C8 alkynyl groups being preferred, and C2-C8 alkenyl groups being preferred. The aryl groups and aralkyl groups include heteroaryl groups and heteroaralkyl groups in which any carbon atom constituting an aromatic ring is substituted with a heteroatom. R 1 and R 2 However, in the case of saturated hydrocarbon groups, examples of hydrocarbon groups include alkyl groups having 1 to 10 carbon atoms.

[0019] Examples of alkenyl groups include vinyl, allyl, methallyl, 2-butenyl, 3-methyl-2-butenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, and 7-octenyl groups. Among these, alkenyl groups having 2 to 6 carbon atoms are preferred from the viewpoint of solubility in the electrolyte, and vinyl and allyl groups are more preferred.

[0020] Examples of alkynyl groups include ethynyl, 2-propynyl, 2-butynyl, 3-butynyl, 4-pentynyl, 5-hexynyl, 6-heptynyl, and 7-octinyl groups. Among these, alkynyl groups with 2 to 6 carbon atoms are preferred from the viewpoint of solubility in the electrolyte, and ethynyl groups are more preferred.

[0021] Examples of aryl groups include phenyl, 1-naphthyl, 2-naphthyl, 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-pyrrolyl, 3-pyrrolyl, and benzyl groups. Among these, aryl groups with 6 to 12 carbon atoms are preferred from the viewpoint of solubility in electrolytes, and phenyl groups are more preferred.

[0022] Examples of aralkyl groups include benzyl groups, phenethyl groups, phenylpropyl groups, phenylbutyl groups, and phenylisopropyl groups. Among these, benzyl groups and phenethyl groups are preferred from the viewpoint of electrolyte solubility, and benzyl groups are more preferred.

[0023] Examples of alkyl groups include methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, n-pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. Among these, alkyl groups having 1 to 6 carbon atoms are preferred from the viewpoint of solubility in the electrolyte, and methyl, ethyl, and iso-propyl groups are more preferred.

[0024] Since compound (A) tends to react and increase in volume on the electrode, in formula (I), R 1 and R 2Preferably, each is independently selected from a hydrogen atom, a halogen atom, a vinyl group, and an allyl group, R 1 and R 2 Either one of them is selected from vinyl groups and allyl groups. Among them, R 1 and R 2 A combination in which one of the elements is a vinyl group and the other is a hydrogen atom is preferred.

[0025] R in equation (I) 1 and R 2 These may be bonded together to form a cyclic structure. Examples of cyclic structures include unsaturated carbon rings other than aromatic rings, such as cyclohexene rings and cyclopentene rings. Among these, cyclohexene rings are preferred from the viewpoint of stability in electrolytes.

[0026] Also, R 1 or R 2 If the group is a hydrocarbon group, the carbon atoms in the hydrocarbon group may be substituted with oxygen atoms, and the hydrogen atoms may be substituted with halogen atoms. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, or iodine atoms.

[0027] Among the compounds (A) represented by formula (I), X 1 X is an oxygen atom. 2 A compound represented by the following formula (II) is preferred, having a sulfite ester structure in which is an oxygen atom and n is 1.

[0028] [ka]

[0029] In formula (II), R 1 and R 2 R in equation (I) 1 and R 2 It is synonymous with [the above].

[0030] Examples of compounds represented by formula (II) include those represented by the following structural formulas.

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] Among the compounds listed above, the compound represented by formula (II) is preferably the one represented by the following structural formula.

[0035] [ka]

[0036] Among the compounds represented by formula (II) above, compounds represented by the following structural formula are more preferably included.

[0037] [ka]

[0038] Among the compounds represented by formula (II) above, compounds represented by the following structural formula are even more preferred.

[0039] [ka]

[0040] Among the compounds represented by the above formula (II), the compounds represented by the following structural formula are particularly preferred.

[0041] [ka] Among the compounds represented by the above formula (II), the most preferred is the compound represented by the following structural formula.

[0042] [ka]

[0043] Furthermore, specific examples of compounds represented by formula (I) other than those represented by formula (II) are shown below.

[0044] In formula (I), X 1 CH2, X 2 Examples of compounds having a sulfone structure where is CH2 and n is 2 include the compounds represented by the following structural formulas.

[0045] [ka]

[0046] In formula (I), X 1 X is an oxygen atom. 2 Examples of compounds having a sulfonic acid ester structure in which is CH2 and n is 2 include the compounds represented by the following structural formulas.

[0047] [ka]

[0048] In formula (I), X 1 CH2, X 2 Examples of compounds having a sulfonic acid ester structure in which is an oxygen atom and n is 2 include the compounds represented by the following structural formulas.

[0049] [ka]

[0050] (Content of compound (A)) The content of compound (A) in the total amount (100% by mass) of the non-aqueous electrolyte is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 8% by mass or less, more preferably 6% by mass or less, and even more preferably 4% by mass or less. If the content of compound (A) is within this range, the capacity retention rate after cycle charging and discharging can be improved in the non-aqueous electrolyte battery, and electrode swelling and resistance after cycling can be suppressed. Compound (A) may be used alone or two or more may be used in any combination and ratio. The identification and measurement of the content of the compound represented by formula (I) are performed by nuclear magnetic resonance (NMR) spectroscopy and / or gas chromatography.

[0051] (Mass ratio of electrolyte to compound (A)) In a non-aqueous electrolyte, the mass ratio of compound (A) content (total amount if there are two or more types) to electrolyte content (compound (A) [g] / electrolyte [g]) is usually 0.001 or higher, preferably 0.01 or higher, more preferably 0.02 or higher, even more preferably 0.025 or higher, even more preferably 0.03 or higher, and usually 0.5 or lower, preferably 0.3 or lower, more preferably 0.2 or lower, and even more preferably 0.1 or lower. When the mass ratio is within this range, the capacity retention rate after cycle charging and discharging can be improved in a non-aqueous electrolyte battery, and electrode swelling and resistance after cycling can be suppressed. The principle behind this effect is not clear, but it is thought that by setting the mass ratio of compound (A) content to electrolyte content within this range, side reactions of the electrolyte within the battery system are minimized.

[0052] [1-2. Electrolytes] Examples of electrolytes for non-aqueous electrolytes include lithium salts. There are no particular restrictions on the lithium salts used, and any can be used, but examples include lithium fluoroborate salts, lithium fluorophosphate salts, lithium tungstate salts, lithium carboxylate salts, lithium sulfonate salts, lithium imide salts, lithium methide salts, lithium oxalate salts, and fluorine-containing organic lithium salts.

[0053] Among these, from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, lithium fluoroborate salts such as LiBF4; lithium fluorophosphate salts such as LiPF6, Li2PO3F, and LiPO2F2; lithium sulfonate salts such as LiSO3F and LiCH3SO3; and lithium imide salts such as LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, LiN(C2F5SO2)2, lithium cyclic 1,2-perfluoroethanedisulfonylimide, and lithium cyclic 1,3-perfluoropropanedi Sulfonylimide; LiC(FSO2)3, LiC(CF3SO2)3, LiC(C2F5SO2)3 as lithium methide salts; lithium difluorooxalate borate, lithium bis(oxalate) borate, lithium tetrafluorooxalate phosphate, lithium difluorobis(oxalate) phosphate, lithium tris(oxalate) phosphate, etc. are preferred as lithium oxalate salts, one or more selected from LiPF6, LiN(FSO2)2, lithium bis(oxalate) borate, and LiSO3F are more preferred, and LiPF6 is particularly preferred.

[0054] The above electrolytes can be used individually or in combination of two or more in any ratio. There are no particular restrictions on the combination of two or more electrolytes, and examples include combinations of LiPF6 and LiN(FSO2)2, LiPF6 and LiBF4, LiPF6 and LiN(CF3SO2)2, LiBF4 and LiN(FSO2)2, and LiBF4, LiPF6 and LiN(FSO2)2. Among these, combinations of LiPF6 and LiN(FSO2)2, LiPF6 and LiBF4, and LiBF4, LiPF6 and LiN(FSO2)2 are preferred.

[0055] While there are no particular restrictions on the total concentration of the electrolyte, from the viewpoint of ensuring proper electrical conductivity for battery operation and sufficient output characteristics, it is usually 8% by mass or more, preferably 8.5% by mass or more, more preferably 9% by mass or more, relative to the total amount of the non-aqueous electrolyte, and also usually 18% by mass or less, preferably 17% by mass or less, more preferably 16% by mass or less. Identification and measurement of the electrolyte content are performed by nuclear magnetic resonance (NMR) spectroscopy and / or ion chromatography.

[0056] [1-3. Non-aqueous solvents] The non-aqueous electrolyte, like other general non-aqueous electrolytes, contains a non-aqueous solvent. There are no particular restrictions on the non-aqueous solvent as long as it dissolves the electrolyte mentioned above; any known organic solvent can be used. Examples of organic solvents include, but are not limited to, saturated cyclic carbonates, linear carbonates, linear carboxylic acid esters, cyclic carboxylic acid esters, cyclic ether compounds, and sulfone compounds.

[0057] Organic solvents can be used individually or in combination of two or more in any ratio. There are no particular restrictions on the combination of two or more organic solvents, but examples include combinations of saturated cyclic carbonates and linear carbonates, combinations of cyclic carboxylic acid esters and linear carbonates, and combinations of saturated cyclic carbonates, linear carbonates and linear carboxylic acid esters. Among these, combinations of saturated cyclic carbonates and linear carbonates, and combinations of saturated cyclic carbonates, linear carbonates and linear carboxylic acid esters are preferred, and combinations of saturated cyclic carbonates and linear carbonates are more preferred. In particular, combinations with ethylene carbonate and at least one selected from the group consisting of ethyl methyl carbonate, dimethyl carbonate, and diethyl carbonate are even more preferred.

[0058] [1-3-1. Saturated Cyclic Carbonates] Examples of saturated cyclic carbonates include those having alkylene groups with 2 to 4 carbon atoms. From the viewpoint of improving battery characteristics due to an increased degree of dissociation of metal ions, particularly lithium ions, saturated cyclic carbonates having alkylene groups with 2 to 3 carbon atoms are preferred. Specific examples of saturated cyclic carbonates include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate or propylene carbonate is preferred, and ethylene carbonate, which is less susceptible to oxidation and reduction, is more preferred. Saturated cyclic carbonates can be used individually or in combination of two or more in any ratio.

[0059] The content of saturated cyclic carbonate is not particularly limited and is arbitrary as long as it does not impair the effects of the invention according to this embodiment. The content of saturated cyclic carbonate is usually 3% by volume or more, preferably 5% by volume or more, relative to the total amount of non-aqueous solvent, while it is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By keeping it within this range, a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte is avoided, making it easier to achieve good high-current discharge characteristics, stability to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery, improving the oxidation-reduction resistance of the non-aqueous electrolyte and tending to improve stability during high-temperature storage. In this specification, volume percent refers to volume percent at 25°C and 1 atmosphere.

[0060] [1-3-2. Chain-like carbonates] Examples of chain-like carbonates include those having 3 to 7 carbon atoms, and chain-like carbonates having 3 to 5 carbon atoms are preferred in order to adjust the viscosity of the non-aqueous electrolyte to an appropriate range. Specific examples of chain-like carbonates include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, and the like, and preferably one or more selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Furthermore, chain-like carbonates containing fluorine atoms (hereinafter also referred to as "fluorinated chain-like carbonates") can also be suitably used. The number of fluorine atoms in a fluorinated chain-like carbonate is not particularly limited as long as it is 1 or more, but is preferably 6 or less, and more preferably 4 or less. When a fluorinated chain-like carbonate has multiple fluorine atoms, these multiple fluorine atoms may be bonded to the same carbon or to different carbons. Examples of fluorinated chain carbonates include fluorinated dimethyl carbonate derivatives such as fluoromethylmethyl carbonate; fluorinated ethylmethyl carbonate derivatives such as 2-fluoroethylmethyl carbonate; and fluorinated diethyl carbonate derivatives such as ethyl-(2-fluoroethyl) carbonate. Chain-like carbonates can be used individually or in combination of two or more types in any ratio.

[0061] The content of chain-like carbonates is not particularly limited, but from the viewpoint of setting the viscosity of the non-aqueous electrolyte within an appropriate range, suppressing a decrease in ionic conductivity, and thereby improving the output characteristics of the non-aqueous electrolyte battery, it is usually 15% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more, and also usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte.

[0062] Furthermore, by combining specific chain-like carbonates with ethylene carbonate in specific quantities, battery performance can be significantly improved. For example, when diethyl carbonate and ethyl methyl carbonate are selected as the specific chain carbonates, the ethylene carbonate content is typically 15% by volume or more, preferably 20% by volume or more, and typically 40% by volume or less, preferably 35% by volume or less, relative to the total amount of solvent in the non-aqueous electrolyte, from the viewpoint of improving high-temperature stability and suppressing gas generation. The diethyl carbonate content is typically 15% by volume or more, preferably 20% by volume or more, and typically 40% by volume or less, preferably 35% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte. The ethyl methyl carbonate content is typically 30% by volume or more, preferably 35% by volume or more, and typically 50% by volume or less, preferably 45% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte.

[0063] [1-3-3. Chain-like carboxylic acid esters] Examples of linear carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, methyl valerate, methyl isobutyrate, ethyl isobutyrate, and methyl pivalate. Among these, methyl acetate, ethyl acetate, propyl acetate, and butyl acetate are preferred from the viewpoint of improving battery characteristics. Linear carboxylic acid esters in which some of the hydrogen atoms of the above compounds are substituted with fluorine atoms (for example, methyl trifluoroacetate, ethyl trifluoroacetate, etc.) can also be suitably used. When a chain-like carboxylic acid ester is included, the amount it is added is usually 1% by volume or more, preferably 5% by volume or more, and more preferably 15% by volume or more, relative to the total amount of the non-aqueous solvent, from the viewpoint of improving the electrical conductivity of the non-aqueous electrolyte and improving the high-current discharge characteristics of the non-aqueous electrolyte battery. Furthermore, the upper limit of the amount added is usually 70% by volume or less, preferably 50% by volume or less, and more preferably 40% by volume or less, from the viewpoint of keeping the viscosity of the non-aqueous electrolyte within an appropriate range, avoiding a decrease in electrical conductivity, suppressing an increase in negative electrode resistance, and keeping the high-current discharge characteristics of the non-aqueous electrolyte battery within a good range.

[0064] [1-3-4. Cyclic carboxylic acid esters] Examples of cyclic carboxylic acid esters include γ-butyrolactone and γ-valerolactone. Of these, γ-butyrolactone is more preferred. Cyclic carboxylic acid esters obtained by substituting some of the hydrogen atoms of the above compounds with fluorine atoms can also be suitably used. When the non-aqueous electrolyte contains a cyclic carboxylic acid ester, its content is usually 1% by volume or more, preferably 5% by volume or more, and more preferably 15% by volume or more, relative to the total amount of the non-aqueous solvent, from the viewpoint of improving the electrical conductivity of the non-aqueous electrolyte and improving the high-current discharge characteristics of the non-aqueous electrolyte battery. Furthermore, the upper limit of its blending amount is usually 70% by volume or less, preferably 50% by volume or less, and more preferably 40% by volume or less, from the viewpoint of keeping the viscosity of the non-aqueous electrolyte within an appropriate range, avoiding a decrease in electrical conductivity, suppressing an increase in negative electrode resistance, and keeping the high-current discharge characteristics of the non-aqueous electrolyte battery within a good range.

[0065] [1-3-5. Cyclic ether compounds] Examples of cyclic ether compounds include cyclic ethers having 3 to 6 carbon atoms, such as tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, and 1,4-dioxane. Some of the hydrogen atoms in these cyclic ether compounds may be substituted with fluorine atoms. Among these, tetrahydrofuran, 1,3-dioxane, and 1,4-dioxane are preferred from the viewpoint of providing high ionic conductivity.

[0066] When the non-aqueous electrolyte contains a cyclic ether compound, its content is arbitrary as long as it does not impair the effects of the present invention, but is usually 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, and usually 30% by volume or less, preferably 25% by volume or less, and more preferably 20% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte. If the content of the cyclic ether compound is within the above range, it is easy to ensure the effect of improving the degree of dissociation of metal ions, especially lithium ions, by the cyclic ether compound and improving ionic conductivity due to the reduction in viscosity of the non-aqueous electrolyte. Furthermore, when the negative electrode active material is a carbon-based material, the phenomenon of co-insertion of chain-like ethers together with metal ions, especially lithium ions, can be suppressed, so that the input / output characteristics and charge / discharge rate characteristics can be set within an appropriate range.

[0067] [1-3-6. Sulfone compounds] The sulfone compound is not particularly limited and may be a cyclic sulfone or a linear sulfone. In the case of a cyclic sulfone, the number of carbon atoms is usually 3 to 6, preferably 3 to 5, and in the case of a linear sulfone, the number of carbon atoms is usually 2 to 6, preferably 2 to 5. Furthermore, the number of sulfonyl groups in one molecule of the sulfone compound is not particularly limited, but is usually 1 or 2. Examples of cyclic sulfones include monosulfone compounds such as trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones; and disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones. Among these, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferred from the viewpoint of dielectric constant and viscosity, and tetramethylene sulfones (sulfolanes) are even more preferred. Sulfolanes and sulfolane derivatives are preferred as sulforanes. Sulfolane derivatives are preferred in which one or more hydrogen atoms bonded to the carbon atoms constituting the sulfolane ring are substituted with fluorine atoms, alkyl groups, or fluorine-substituted alkyl groups. Among these, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,3-difluorosulfolane, 2-trifluoromethylsulfolane, and 3-trifluoromethylsulfolane are preferred because they have high ionic conductivity and high input / output properties.

[0068] Furthermore, examples of chain-like sulfones include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, and pentafluoroethyl methyl sulfone. Among these, dimethyl sulfone, ethyl methyl sulfone, and monofluoromethyl methyl sulfone are preferred because they improve the high-temperature storage stability of non-aqueous electrolytes. If the non-aqueous electrolyte contains a sulfone compound, the amount is arbitrary as long as it does not impair the effects of the present invention. However, from the viewpoint of improving high-temperature storage stability, the amount is usually 0.3% by volume or more, preferably 0.5% by volume or more, more preferably 1% by volume or more, relative to the total amount of the non-aqueous solvent in the non-aqueous electrolyte, and is usually 40% by volume or less, preferably 35% by volume or less, more preferably 30% by volume or less.

[0069] [1-4. Auxiliary Agents] Examples of additives that may be contained in non-aqueous electrolytes include cyclic carbonates having carbon-carbon unsaturated bonds, fluorine-containing cyclic carbonates, compounds having isocyanate groups, organic compounds having an isocyanuric acid skeleton, sulfur-containing organic compounds, phosphorus-containing organic compounds, organic compounds having cyano groups, silicon-containing compounds, aromatic compounds, fluorine-free carboxylic acid esters, cyclic compounds having ether bonds, carboxylic acid anhydrides, compounds containing borate anions, compounds containing phosphate anions having PF and P=O bonds, compounds containing anions having S=O bonds, and compounds containing oxalate complex anions. For example, compounds described in International Publication No. 2015 / 111676 can be cited. Among these, at least one anion-containing compound selected from phosphate anion-containing compounds having PF bonds and P=O bonds, anion-containing compounds having S=O bonds, and oxalate complex anion-containing compounds (hereinafter also referred to as "specific anion-containing compounds"), and / or at least one carbonate compound selected from cyclic carbonates having carbon-carbon unsaturated bonds and fluorine-containing cyclic carbonates (hereinafter also referred to as "specific carbonate compounds"). The content of the auxiliary agent is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and particularly preferably less than 1% by mass, relative to the total amount of the non-aqueous electrolyte. Cyclic compounds containing ether bonds can be used as additives in non-aqueous electrolytes, and some can also be used as non-aqueous solvents as described in "1-3. Non-aqueous Solvents". When using cyclic compounds containing ether bonds as additives, use them in amounts less than 4% by mass. Compounds containing borate anions, compounds containing oxalate complex anions, compounds containing monofluorophosphate anions, and compounds containing difluorophosphate anions can be used as additives in non-aqueous electrolytes, and some can also be used as electrolytes as described in "1-2. Electrolytes". When using these compounds as additives, use them in amounts less than 3% by mass.

[0070] [1-4-1. Compounds containing specific anions] The aforementioned specific anion-containing compound is usually an acid or a salt. The aforementioned specific anion-containing compound is preferably a salt, and as the countercation, alkali metal cations such as lithium, sodium, and potassium are preferred, with lithium cations being more preferred. At least one anion-containing compound selected from phosphate anion-containing compounds having PF bonds and P=O bonds, anion-containing compounds having S=O bonds, and oxalate complex anion-containing compounds can be used individually or in combination of two or more in any ratio. Among these, compounds containing phosphate anions having PF bonds and P=O bonds are preferred from the viewpoint of suppressing electrode swelling and resistance after cycling.

[0071] [1-4-1-1. Compounds containing phosphate anions with PF bonds and P=O bonds] Examples of phosphate anion-containing compounds having PF bonds and P=O bonds include PO3F - Monofluorophosphate anions such as PO2F2 - Examples of compounds containing difluorophosphate anions include the following. Examples of salts of phosphate anions having PF and P=O bonds include salts of monofluorophosphate anions such as Li2PO3F; and salts of difluorophosphate anions such as LiPO2F2, NaPO2F2, and KPO2F2. Among these, compounds containing difluorophosphate anions are preferred from the viewpoint of balancing battery output characteristics and electrode interface protection, and lithium difluorophosphate is more preferred.

[0072] [1-4-1-2. Anion-containing compounds with an S=O bond] Examples of anion-containing compounds having an S=O bond include FSO3. - Fluorosulfonate anions such as (FSO2)2N - , (FSO2)(CF3SO2)N - Fluorosulfonylimid anions such as (FSO2)3C - Compounds containing fluorosulfonylmethide anions such as CH3SO4 - Examples include compounds containing alkyl sulfate anions, etc. Examples of salts of anions having an S=O bond include salts of fluorosulfonic acid anions such as LiSO3F, NaSO3F, KSO3F, (CH3)4NSO3F, (C2H5)4NSO3F, and (n-C4H9)4NSO3F; salts of fluorosulfonylimide anions such as LiN(FSO2)2 and LiN(FSO2)(CF3SO2); salts of fluorosulfonylmethide anions such as LiC(FSO2)3; and salts of alkyl sulfate anions such as LiCH3SO4 and LiC2H5SO4. Among these, from the viewpoint of balancing the output characteristics of the battery and the protection of the electrode interface, compounds containing a fluorosulfonate anion or a fluorosulfonylimide anion are preferred, salts of fluorosulfonate anions or fluorosulfonylimide anions are more preferred, salts of fluorosulfonate anions are even more preferred, and lithium fluorosulfonate is particularly preferred.

[0073] [1-4-1-3. Compounds containing oxalate complex anions] A compound containing an oxalate complex anion is not particularly limited as long as it contains an anion having an oxalate complex within its molecule. An oxalate complex anion-containing compound is a compound containing an acid anion in which oxalic acid is coordinated to or bonded to a central atom to form a complex. Examples include a boron oxalate complex anion in which oxalic acid is coordinated to or bonded to a boron atom, and a phosphorus oxalate complex anion in which oxalic acid is coordinated to or bonded to a phosphorus atom. Examples of boron oxalate complex anions include bis(oxalate)borate anions and difluorooxalateborate anions, while examples of phosphorus oxalate complex anions include tetrafluorooxalate phosphate anions, difluorobis(oxalate)phosphate anions, and tris(oxalate)phosphate anions. Examples of oxalate complex anion-containing compounds include salts of boron oxalate complex anions such as lithium bis(oxalate)borate and lithium difluorooxalateborate; and salts of phosphorus oxalate complex anions such as lithium tetrafluorooxalate phosphate, lithium difluorobis(oxalate)phosphate and lithium tris(oxalate)phosphate. Among these, from the viewpoint of forming a stable composite film on the electrode surface, compounds containing boron oxalate complex anions are preferred, compounds containing bis(oxalate)borate anions are more preferred, and lithium bis(oxalate)borate is particularly preferred.

[0074] (Content of specific anion-containing compounds) When the non-aqueous electrolyte contains a specific anion-containing compound, the amount of the specific anion-containing compound in the total amount of the non-aqueous electrolyte (total amount if there are two or more types) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, and also preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less. If the content of specific anion-containing compounds is within the above range, battery characteristics, particularly the capacity retention rate after cycle charging and discharging, can be significantly improved, and electrode swelling and resistance after cycling can be significantly suppressed. The reason for this is not entirely clear, but it is thought that if the content of specific anion-containing compounds is within the above range, side reactions of the non-aqueous electrolyte components on the electrode surface can be minimized. The identification and measurement of the content of specific anion-containing compounds are performed by nuclear magnetic resonance (NMR) spectroscopy and / or ion chromatography.

[0075] (Mass ratio of a specific anion-containing compound to compound (A)) The mass ratio of the content of a specific anion-containing compound (total amount if there are two or more types) to the content of compound (A) (specific anion-containing compound [g] / compound (A) [g]) is usually 0.01 or higher, preferably 0.05 or higher, more preferably 0.3 or higher, and usually 100 or lower, preferably 10 or lower, more preferably 5 or lower, and even more preferably 4 or lower. If the aforementioned mass ratio is within the above range, the battery characteristics, particularly the capacity retention rate after cycle charging and discharging, can be significantly improved, and electrode swelling and resistance after cycling can be significantly suppressed. The reason for this is not entirely clear, but it is thought that by including compound (A) and a specific anion-containing compound within the above mass ratio range, side reactions of the non-aqueous electrolyte components on the electrode surface can be minimized.

[0076] (Mass ratio of a specific anion-containing compound to an electrolyte) When a non-aqueous electrolyte contains a specific anion-containing compound, the mass ratio of the content of the specific anion-containing compound (total amount if there are two or more types) to the electrolyte content (specific anion-containing compound [g] / electrolyte [g]) is usually 0.00005 or more, preferably 0.001 or more, more preferably 0.01 or more, even more preferably 0.02 or more, and even more preferably 0.025 or more, and also usually 0.5 or less, preferably 0.45 or less, more preferably 0.4 or less, and even more preferably 0.35 or less. If the aforementioned mass ratio is within the above range, the battery characteristics, particularly the capacity retention rate after cycle charging and discharging, can be significantly improved, and electrode swelling and resistance after cycling can be significantly suppressed. The reason for this is not entirely clear, but it is thought that by including a specific anion-containing compound and electrolyte within the above mass ratio range, side reactions of the electrolyte within the battery system are minimized.

[0077] [1-4-2. Specific Carbonate Compounds] The non-aqueous electrolyte preferably contains at least one carbonate compound selected from the group consisting of cyclic carbonates having carbon-carbon unsaturated bonds and cyclic carbonates having fluorine atoms. Among these, it is preferable to include a cyclic carbonate having carbon-carbon unsaturated bonds, and more preferable to include vinylene carbonate. These can be used individually or in combination of two or more in any ratio. It is preferable to combine an unsaturated cyclic carbonate and a fluorinated cyclic carbonate, more preferable to combine vinylene carbonate and a fluorinated cyclic carbonate, and even more preferable to combine an unsaturated cyclic carbonate and a monofluoroethylene carbonate.

[0078] (Content of specific carbonate compounds) The content of specific carbonate compounds (total amount if there are two or more types) in the total amount of non-aqueous electrolyte is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, and also usually 10% by mass or less, preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less. If the content of specific carbonate compounds is within the above range, battery characteristics, particularly the capacity retention rate after cycle charging and discharging, can be improved. The reason for this is not entirely clear, but it is thought that by including the carbonate compounds in this ratio, a film is formed on the electrodes, minimizing side reactions of the components of the non-aqueous electrolyte. The identification and measurement of the content of specific carbonate compounds are performed by nuclear magnetic resonance (NMR) spectroscopy and / or gas chromatography.

[0079] (Mass ratio of a specific carbonate compound to compound (A)) The mass ratio of the content of a specific carbonate compound (total amount if there are two or more types) to the content of compound (A) (specific carbonate compound [g] / compound (A) [g]) is usually 0.01 or higher, preferably 0.05 or higher, more preferably 0.3 or higher, and even more preferably 0.5 or higher, and also usually 100 or lower, preferably 10 or lower, more preferably 5 or lower, and even more preferably 4 or lower. If the mass ratio is within the above range, the battery characteristics, in particular the capacity retention rate after cycle charging and discharging, can be improved. The reason for this is not clear, but it is thought that by including a specific carbonate compound within the above mass ratio range, a film is formed on the electrode, minimizing side reactions of the components of the non-aqueous electrolyte.

[0080] (Mass ratio of a specific carbonate compound to an electrolyte) In a non-aqueous electrolyte, the mass ratio of the content of a specific carbonate compound (total amount if there are two or more types) to the electrolyte content (specific carbonate compound [g] / electrolyte [g]) is usually 0.00005 or higher, preferably 0.001 or higher, more preferably 0.01 or higher, even more preferably 0.02 or higher, and even more preferably 0.025 or higher. Also, it is usually 0.5 or lower, preferably 0.45 or lower, more preferably 0.4 or lower, and even more preferably 0.35 or lower. If the mass ratio is within the above range, the battery characteristics, in particular the capacity retention rate after cycle charging and discharging, can be improved. The reason for this is not clear, but it is thought that by including the carbonate compound and electrolyte within the above mass ratio range, a film is formed on the electrode, and side reactions of the electrolyte within the battery system are minimized.

[0081] [1-4-2-1. Cyclic carbonates containing carbon-carbon unsaturated bonds] There are no particular restrictions on cyclic carbonates having carbon-carbon unsaturated bonds (hereinafter also referred to as "unsaturated cyclic carbonates"), as long as they have carbon-carbon double bonds or carbon-carbon triple bonds. Cyclic carbonates having aromatic rings are also included in the category of unsaturated cyclic carbonates. Examples of unsaturated cyclic carbonates include vinylene carbonates, ethylene carbonates substituted with aromatic rings, carbon-carbon double bonds, or carbon-carbon triple bonds, phenyl carbonates, vinyl carbonates, allyl carbonates, and catechol carbonates. Among these, vinylene carbonates and ethylene carbonates substituted with aromatic rings, or carbon-carbon double bonds, or carbon-carbon triple bonds are preferred. 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, and 4,5-diallyl vinylene carbonate. Examples of ethylene carbonates substituted with substituents having aromatic rings or carbon-carbon double or carbon-carbon triple bonds include vinylethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4-methyl-5-ethynylethylene carbonate, 4-vinyl-5-ethynylethylene carbonate, 4-allyl-5-ethynylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, and 4-methyl-5-allylethylene carbonate. Among these, vinylene carbonate, vinylethylene carbonate, and ethynylethylene carbonate are preferred because they form an even more stable composite film on the negative electrode, one or more selected from vinylene carbonate and vinylethylene carbonate are more preferred, and vinylene carbonate is even more preferred. Unsaturated cyclic carbonates can be used individually or in combination of two or more in any ratio.

[0082] [1-4-2-2. Cyclic carbonates containing fluorine atoms] A cyclic carbonate containing a fluorine atom is not particularly limited as long as it has a cyclic carbonate structure and contains a fluorine atom. Examples of cyclic carbonates containing fluorine atoms include fluorinated cyclic carbonates having alkylene groups with 2 to 6 carbon atoms, and their derivatives. Examples include fluorinated ethylene carbonates (fluoroethylene carbonates) and their derivatives, as well as ethylene carbonates containing fluorine groups. Examples of derivatives of fluorinated ethylene carbonates include fluorinated ethylene carbonates substituted with alkyl groups (for example, alkyl groups with 1 to 4 carbon atoms). Among these, fluoroethylene carbonates with 1 to 8 fluorine atoms and their derivatives are preferred. Examples of fluoroethylene carbonates and their derivatives having 1 to 8 fluorine atoms, as well as ethylene carbonates having a fluorine-containing group, include monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4-(fluoromethyl)-ethylene carbonate, 4-(difluoromethyl)-ethylene carbonate, 4-(trifluoromethyl)-ethylene carbonate, 4-(fluoromethyl)-4-fluoroethylene carbonate, 4-(fluoromethyl)-5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene carbonate, and 4,4-difluoro-5,5-dimethylethylene carbonate. Among these, one or more selected from monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate are preferred from the viewpoint of providing high ionic conductivity to the electrolyte and facilitating the formation of a stable interfacial protective film. Cyclic carbonates containing fluorine atoms can be used individually or in combination of two or more in any ratio.

[0083] [2.Nonaqueous electrolyte battery] The present invention relates to a non-aqueous electrolyte battery comprising a positive electrode having a positive electrode active material capable of intercalating and releasing metal ions, and a negative electrode having a negative electrode active material capable of intercalating and releasing metal ions, characterized in that it comprises the above-mentioned non-aqueous electrolyte, and the negative electrode active material contains a material comprising a metal element and / or metalloid element that can alloy with Li. Examples of non-aqueous electrolyte batteries of the present invention include polyvalent cation batteries, metal-air secondary batteries, and secondary batteries using s-block metals other than those mentioned above, with non-aqueous electrolyte secondary batteries being preferred and lithium-ion secondary batteries being more preferred. In the non-aqueous electrolyte battery of the present invention, the configuration excluding the non-aqueous electrolyte described above will be explained below using a lithium-ion secondary battery as an example.

[0084] [2-1. Positive electrode] The positive electrode has a positive electrode active material capable of intercalating and releasing metal ions on at least a portion of the current collector surface. The metal ions are preferably lithium ions, and the positive electrode active material preferably contains a lithium transition metal compound.

[0085] [2-1-1. Positive electrode active material] The following describes the positive electrode active material (lithium transition metal compound) used in the positive electrode.

[0086] [2-1-1-1. Lithium transition metal compounds] Lithium transition metal compounds are compounds having a structure that allows for the removal and insertion of lithium ions. Examples include sulfides, phosphate compounds, silicate compounds, borate compounds, and lithium transition metal composite oxides. Among these, phosphate compounds or lithium transition metal composite oxides are preferred, and lithium transition metal composite oxides are more preferred. Examples of the lithium transition metal composite oxide include those belonging to the spinel structure allowing three-dimensional diffusion and the layered structure allowing two-dimensional diffusion of lithium ions.

[0087] The lithium transition metal composite oxide having a spinel structure is generally represented by the following formula (1). Li x M2O4(1) (In formula (1), x satisfies 1 ≤ x ≤ 1.5, and M represents one or more transition metal elements.) Specific examples of the oxide represented by formula (1) include LiMn2O4, LiCoMnO4, LiNi 0.5 Mn 1.5 O4, LiCoVO4, and the like.

[0088] The lithium transition metal composite oxide having a layered structure is generally represented by the following composition formula (2). Li 1+y MO2(2) (In formula (2), y satisfies -0.1 ≤ y ≤ 0.5, and M represents one or more transition metal elements.) Specific examples of the oxide represented by formula (2) include LiCoO2, LiNiO2, LiNi 0.85 Co 0.10 Al 0.05 O2, LiNi 0.80 Co 0.15 Al 0.05 O2, LiNi 0.34 Co 0.33 Mn 0.33 O2, Li 1.05 Ni 0.34 Co 0.33 Mn 0.33 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.5 Co 0.2 Mn 0.3 O​​​​​​​​​​​​​​0.06 Mn 0.03 O2, LiNi 0.91 Co 0.06 Al 0.03 O2, LiNi 0.90 Co 0.03 Al 0.07 O2, Li 1.05 Ni 0.34 Co 0.33 Mn 0.33 O2, Li 1.00 Ni 0.61 Co 0.20 Mn 0.19 Examples include O2 and the like. <​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​In formula (4) above, b2 is preferably 0.40 or higher, more preferably 0.50 or higher, and particularly preferably 0.60 or higher. Also, d2 is preferably 0.01 or higher, and more preferably 0.10 or higher. A preferred example of the lithium transition metal composite oxide represented by the above formula (4) is LiNi 0.85 Co 0.10 Al 0.05 O2, LiLiLi 0.80 Co 0.15 Al 0.05 O2, LiLiLi 0.8 Co 0.1 Mn 0.1 O2, LiLiLi 0.91 Co 0.06 Mn 0.03 O2, LiLiLi 0.91 Co 0.06 Al 0.03 O2, LiLiLi 0.90 Co 0.03 Al 0.07 O2, Li 1.00 Ni 0.61 Co 0.20 Mn 0.19 O2, Li 1.05 Ni 0.34 Co 0.33 Mn 0.33 Examples include O2.

[0091] In the above formulas (1) to (3), from the viewpoint of enhancing the structural stability of the lithium transition metal composite oxide and suppressing structural degradation during repeated charging and discharging, M preferably contains Mn or Al, and more preferably Mn. In formula (4) above, from the viewpoint of enhancing the structural stability of the lithium transition metal composite oxide and suppressing structural degradation during repeated charging and discharging, M preferably contains Mn or Al, and more preferably Mn.

[0092] [2-1-1-2. Introduction of different elements] Furthermore, lithium transition metal composite oxides may contain elements other than those included in any of the above compositional formulas (1) to (3) (other elements).

[0093] [2-1-1-3. Surface coating] As the positive electrode, a positive electrode active material may be used in which a substance with a different composition from the positive electrode active material (surface-adhered substance) is attached to its surface. Examples of surface-adhering substances include oxides such as aluminum oxide, sulfates such as lithium sulfate, and carbonates such as lithium carbonate. These surface-adhering substances can be attached to the surface of the positive electrode active material by, for example, dissolving or suspending them in a solvent, impregnating and adding them to the positive electrode active material, and then drying them. The amount of surface-adhering material is preferably 1 μmol / g or more, more preferably 10 μmol / g or more, and usually 1 mmol / g or less, relative to the positive electrode active material. In this specification, a positive electrode active material with the above-mentioned surface-adhered substance attached to its surface is also referred to as a "positive electrode active material."

[0094] [2-1-1-4. Blend] The positive electrode active material can be used alone or in combination of two or more materials in any ratio.

[0095] [2-1-2. Cathode Configuration and Manufacturing Method] The positive electrode using positive electrode active material can be manufactured by conventional methods. Specifically, the positive electrode can be obtained by a coating method in which the positive electrode active material, binder, and optionally conductive material and thickener are dry-mixed to form a sheet, which is then pressed onto the positive electrode current collector, or by dissolving or dispersing these materials in a liquid medium such as an aqueous solvent or an organic solvent to form a slurry, which is then applied to the positive electrode current collector and dried to form a positive electrode active material layer on the current collector. Alternatively, for example, the above positive electrode active material may be roll-molded to form a sheet electrode, or it may be compressed to form a pellet electrode. The following describes the process of sequentially applying and drying the slurry onto the positive electrode current collector.

[0096] [2-1-2-1. Content of positive electrode active material] The content of the positive electrode active material in the positive electrode active material layer is typically between 80% by mass and 99.5% by mass.

[0097] [2-1-2-2. Electrode density] The positive electrode active material layer obtained by coating and drying is preferably compacted by hand pressing, roller pressing, or the like to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer present on the current collector is typically 1.5 g / cm³. 3 More than 4.5g / cm 3 The following applies:

[0098] [2-1-2-3. Conductive Materials] Any known conductive material can be used as the conductive material. Specific examples include metallic materials such as copper and nickel; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black; and carbon-based materials such as amorphous carbon such as needle coke. The conductive material can be used alone or in combination of two or more materials in any ratio. The conductive material is usually contained in the positive electrode active material layer in an amount of 0.01% by mass or more and 50% by mass or less.

[0099] [2-1-2-4. Binding agent] When forming the positive electrode active material layer by a coating method, the type of binder used is not particularly limited as long as it is a material that can be dissolved or dispersed in the liquid medium for the slurry. For example, fluororesins such as polyvinyl fluoride, polyvinylidene fluoride, and polytetrafluoroethylene are preferred due to their weather resistance, chemical resistance, heat resistance, and flame retardancy; CN group-containing polymers such as polyacrylonitrile and polyvinylidene cyanide are preferred. Furthermore, mixtures of the above polymers, modified products, derivatives, random copolymers, alternating copolymers, graft copolymers, block copolymers, etc., can also be used. The binder can be used alone or in combination of two or more types in any ratio. Furthermore, when a resin is used as a binder, the weight-average molecular weight of the resin can be arbitrary as long as it does not impair the effects of the present invention, and is usually between 10,000 and 3,000,000. When the molecular weight is within this range, the strength of the electrode is improved, and the electrode can be formed suitably. The binder content in the positive electrode active material layer is typically between 0.1% by mass and 80% by mass.

[0100] [2-1-2-5. Current Collector] The material of the positive electrode current collector is not particularly limited, and any known material can be used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, with aluminum being preferred. Examples of current collector shapes include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. Among these, metal foil or metal thin film is preferred. The metal thin film may be formed in a mesh shape as appropriate. When the shape of the positive electrode current collector is plate-shaped or film-shaped, the thickness of the current collector can be arbitrary, but is usually between 1 μm and 1 mm.

[0101] [2-1-2-6. Thickness of the positive electrode plate] The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the positive electrode active material layer, obtained by subtracting the thickness of the current collector from the thickness of the positive electrode plate, is usually between 10 μm and 500 μm on one side of the current collector.

[0102] [2-1-2-7. Surface coating of the positive electrode plate] The positive electrode plate may be one on which a substance with a different composition from the positive electrode plate is attached to its surface, and the substance used may be the same as the surface-attached substance that may be attached to the surface of the positive electrode active material.

[0103] [2-2. Negative electrode] The negative electrode has negative electrode active material on at least a portion of the current collector surface.

[0104] [2-2-1. Negative electrode active material] The negative electrode active material contains a material that includes a metallic element and / or a metalloid element that can be alloyed with Li.

[0105] [2-2-1-1. Materials containing metallic and / or metalloid elements that can be alloyed with Li] Materials containing metal elements and / or metalloid elements that can be alloyed with Li can be any of the conventionally known ones. However, from the viewpoints of capacity and cycle life, for example, it is preferable that they are single substances or compounds of metal and / or metalloid elements that may be coated with carbon and are selected from the group consisting of Sb, Si, Sn, Al, As, and Zn. Further, when the material containing metal elements and / or metalloid elements that can be alloyed with Li contains two or more types of elements, the material may be an alloy material composed of alloys of these metals. Further, the material of metal elements and / or metalloid elements that can be alloyed with Li may already be alloyed with Li at the time of manufacturing the negative electrode described later. Examples of the material of metal elements and / or metalloid elements that can be alloyed with Li include oxides, nitrides, carbides, etc. These may contain two or more types of metal elements and / or metalloid elements that can be alloyed with Li.

[0106] Among them, metallic Si (hereinafter, may be referred to as Si) or Si-containing inorganic compounds are preferable from the viewpoint of increasing the capacity. In this specification, Si or Si-containing inorganic compounds are collectively referred to as Si compounds. Specific examples of Si compounds include SiO x (0 ≦ x ≦ 2), etc. Specific examples of metal compounds alloyed with Li include Li y Si (0 < y ≦ 4.4), Li2SiO 2+z (0 < z ≦ 2), etc. As Si compounds, Si oxides (SiO x1 , 0 < x1 ≦ 2) are preferable in that their theoretical capacity is larger than that of graphite, or amorphous Si or nano-sized Si crystals are preferable in that alkali ions such as lithium ions can easily enter and exit, and a high capacity can be obtained.

[0107] When the material containing metal elements and / or metalloid elements that can be alloyed with Li is in the form of particles, its volume average particle diameter (d50) is usually 0.01 μm or more and 10 μm or less from the viewpoint of cycle life.

[0108] The content of material containing a metallic element and / or metalloid element that can alloy with Li in the negative electrode active material is usually 1% by mass or more and 99% by mass or less. Preferably it is 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. Also, it is usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

[0109] [2-2-1-2. Other negative electrode active materials] Other negative electrode active materials are not particularly limited as long as they are capable of electrochemically intercalating and releasing metal ions. Specific examples include carbon-based materials, lithium-containing metal composite oxide materials, and mixtures thereof. Among these, carbon-based materials are preferred because they offer good cycle characteristics, safety, and excellent continuous charging characteristics. These may be used individually or in any combination of two or more types.

[0110] [2-2-1-3. Carbon-based materials] Examples of carbon-based materials include natural graphite, artificial graphite, amorphous carbon, carbon-coated graphite, graphite-coated graphite, and resin-coated graphite. Among these, natural graphite is preferred. One type of carbon-based material may be used alone, or two or more types may be used in any combination and ratio. Examples of natural graphite include scaly graphite, flake graphite, and / or graphite particles obtained by treating these graphites, such as spheroidization or densification. Among these, spherical or ellipsoidal graphite particles that have undergone spheroidization treatment are particularly preferred from the viewpoint of particle packing properties or charge-discharge rate characteristics. The volume-average particle size (d50) of carbon-based materials is typically between 1 μm and 100 μm.

[0111] The carbon-based material used as the negative electrode active material preferably satisfies at least one of the following physical properties and characteristics such as shape, and is particularly preferable to satisfy multiple of them simultaneously. (1) X-ray diffraction parameters The d-value (interlayer distance) of the lattice plane (002 plane) of carbon-based materials, as determined by X-ray diffraction using the JSPS method, is typically between 0.335 nm and 0.360 nm. Furthermore, the crystallite size (Lc) of carbon-based materials, as determined by X-ray diffraction using the JSPS method, is typically 1.0 nm or greater. (2) Volume-based average particle size The volume-based average particle size of carbon-based materials is the volume-based average particle size (median diameter) determined by laser diffraction and scattering, and is typically between 1 μm and 100 μm. (3) Raman R value, Raman half-width The Raman R value of carbon-based materials is measured using argon ion laser Raman spectroscopy and is typically between 0.01 and 1.5. Also, 1580 cm² of carbon-based materials -1 The Raman width at half maximum in the vicinity is not particularly restricted, but is usually 10 cm. -1 More than 100cm -1 The following applies: (4) BET specific surface area The BET specific surface area of ​​carbon-based materials is the value of the specific surface area measured using the BET method, and is typically 0.1 m². 2 ·g -1 Over 100m 2 ·g -1 The following applies: The negative electrode active material may contain two or more carbon-based materials with different properties. These properties refer to X-ray diffraction parameters, volume-based average particle size, Raman R value, Raman full width at half maximum, and BET specific surface area. Preferred examples include a volume-based particle size distribution that is not symmetrical when centered on the median diameter, the inclusion of two or more carbon-based materials with different Raman R values, and the inclusion of two or more carbon-based materials with different X-ray parameters.

[0112] [2-2-1-4. A mixture of particles of a material containing alloyable metallic and / or metalloid elements with Li, and graphite particles.] The mixture of particles of a material containing a Li alloyable metal element and / or metalloid element used as a negative electrode active material and graphite particles may be a mixture in which the aforementioned particles of the Li alloyable metal element and / or metalloid element and the graphite particles described below are mixed in the state of particles of each material independently of each other, or it may be a composite in which particles of the material containing a Li alloyable metal element and / or metalloid element are present on the surface or inside the graphite particles. The proportion of particles of material containing metal elements and / or metalloid elements that can alloy with Li, relative to the total amount of graphite particles, is usually 1% by mass or more and 99% by mass or less. Preferably, it is 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. Also, it is usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

[0113] [2-2-1-5. Lithium-containing metal composite oxide materials] The lithium-containing metal composite oxide material is not particularly limited as long as it can intercept and release lithium ions. Specifically, from the viewpoint of high current density charge / discharge characteristics, lithium-containing metal composite oxide materials containing titanium are preferred, lithium-titanium composite oxides (hereinafter also referred to as "lithium titanium composite oxides") are more preferred, and lithium titanium composite oxides having a spinel structure are even more preferred because they significantly reduce output resistance. Furthermore, the lithium and / or titanium in the lithium-titanium composite oxide may be substituted with other metallic elements, such as at least one element selected from the group consisting of Al, Ga, Cu, and Zn. As a lithium titanium composite oxide, Li 4 / 3 Ti 5 / 3 O4, Li1Ti2O4 and Li 4 / 5 Ti 11 / 5O4 is preferred. Also, lithium titanium composite oxides in which part of lithium and / or titanium is substituted with other elements are preferred, for example, Li 4 / 3 Ti 4 / 3 Al 1 / 3 O4 is also preferable.

[0114] [2-2-2. Negative electrode configuration and manufacturing method] The negative electrode may be manufactured using any known method, as long as it does not impair the effects of the present invention. For example, it can be manufactured by adding a binder, a liquid medium such as an aqueous solvent or an organic solvent, and optionally a thickener, a conductive material, a filler, etc., to the negative electrode active material to form a slurry, applying this slurry to a current collector, drying it, and then pressing it to form a negative electrode active material layer.

[0115] [2-2-2-1. Content of negative electrode active material] The content of the negative electrode active material in the negative electrode active material layer is typically between 80% by mass and 99.5% by mass.

[0116] [2-2-2-2. Electrode density] The negative electrode active material layer obtained by coating and drying is preferably compacted using a hand press, roller press, or the like to increase the packing density of the negative electrode active material. The electrode structure when the negative electrode active material is used as an electrode is not particularly limited, but the density of the negative electrode active material layer present on the current collector is usually 1 g / cm³. 3 More than 2.2g / cm 3 The following applies:

[0117] [2-2-2-3. Thickening agents] Thickening agents are typically used to adjust the viscosity of slurries. While not particularly limited, examples of thickening agents include carboxymethylcellulose and its salts, methylcellulose, hydroxymethylcellulose, ethylcellulose, and polyvinyl alcohol. These can be used individually or in combination of two or more in any ratio. When a thickening agent is used, the amount of the thickening agent relative to the negative electrode active material is usually between 0.1% by mass and 5% by mass.

[0118] [2-2-2-4. Binding agent] The binder used to bind the negative electrode active material can be any material that is stable with non-aqueous electrolytes or liquid media used during electrode manufacturing, and is not particularly limited. Specific examples include rubbery polymers such as styrene-butadiene rubber (SBR), isoprene rubber, butadiene rubber, fluororubber, acrylonitrile-butadiene rubber (NBR), and ethylene-propylene rubber, as well as fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and tetrafluoroethylene-ethylene copolymers. These can be used individually or in combination of two or more in any ratio. The binder content relative to the negative electrode active material is typically between 0.1% by mass and 20% by mass. In particular, when the binder contains a rubbery polymer such as SBR as its main component, the binder content relative to the negative electrode active material is usually between 0.1% by mass and 5% by mass. Furthermore, when the binder contains a fluorine-based polymer such as polyvinylidene fluoride as its main component, the binder content relative to the negative electrode active material is usually between 1% by mass and 15% by mass.

[0119] [2-2-2-5. Current Collector] Any known material can be used as the current collector for holding the negative electrode active material. Examples of negative electrode current collectors include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel, but copper is particularly preferred in terms of ease of processing and cost. Examples of the negative electrode current collector shape include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. Among these, metal foil or metal thin film is preferred. The metal thin film may be formed in a mesh shape as appropriate. When the negative electrode current collector is plate-shaped or film-shaped, the thickness of the current collector can be arbitrary, but is usually between 1 μm and 1 mm.

[0120] [2-2-2-6. Thickness of the negative electrode plate] The thickness of the negative electrode (negative electrode plate) is designed to match the positive electrode (positive electrode plate) used and is not particularly limited; however, the thickness of the negative electrode active material layer, obtained by subtracting the thickness of the current collector from the thickness of the negative electrode material, is usually between 15 μm and 300 μm.

[0121] [2-2-2-7. Surface coating of the negative electrode plate] Furthermore, the negative electrode plate may also be one in which a substance with a different composition from the negative electrode active material is attached to its surface (surface-attached substance). Examples of surface-attached substances include oxides such as aluminum oxide, sulfates such as lithium sulfate, and carbonates such as lithium carbonate.

[0122] [2-3. Separator] A separator is usually placed between the positive and negative electrodes to prevent short circuits. In this case, the non-aqueous electrolyte is typically used by impregnating this separator. There are no particular restrictions on the material or shape of the separator; any known material or shape can be used as long as it does not impair the effects of the present invention.

[0123] [2-4.Battery design] [2-4-1. Electrode group] The electrode group may be either a laminated structure in which the positive electrode plate and the negative electrode plate are separated by the separator, or a structure in which the positive electrode plate and the negative electrode plate are spirally wound around the separator. The ratio of the volume of the electrode group to the internal volume of the battery (electrode group occupancy rate) is usually between 40% and 90%.

[0124] [2-4-2. Current collection structure] In electrode groups with the aforementioned layered structure, a structure formed by bundling the metal core portions of each electrode layer and welding them to a terminal is preferably used. A structure that reduces resistance by providing multiple terminals within the electrode is also preferably used. In electrode groups with the aforementioned wound structure, the internal resistance can be reduced by providing multiple lead structures in both the positive and negative electrodes and bundling them to a terminal.

[0125] [2-4-3. Protective Elements] As protective elements, PTC (Positive Temperature Coefficient) elements whose resistance increases with heat generation due to excessive current, thermal fuses, thermistors, and valves (current interruption valves) that interrupt the current flowing through the circuit due to a rapid rise in internal pressure or temperature of the battery in the event of abnormal heat generation can be used. It is preferable to select the above protective elements that do not operate under normal high-current use, and it is even more preferable to design the system so that abnormal heat generation or thermal runaway does not occur even without protective elements.

[0126] [2-4-4. Exterior] Non-aqueous electrolyte batteries are typically constructed by housing the non-aqueous electrolyte, negative electrode, positive electrode, separator, etc., of the present invention within an outer casing (outer case). There are no restrictions on this outer casing; any known material can be used as long as it does not impair the effects of the present invention. The material of the outer casing can be any substance that is stable with respect to the non-aqueous electrolyte used, and is not particularly limited. However, from the viewpoint of weight reduction and cost, metals such as iron, aluminum, aluminum alloys, or laminated films are preferably used. Iron is particularly preferred due to its pressure resistance required to operate the current interruption valve. Outer cases using the above-mentioned metals include those that create a sealed structure by welding the metals together using laser welding, resistance welding, or ultrasonic welding, or those that create a crimped structure using the above-mentioned metals via a resin gasket.

[0127] [2-4-5. Shape] Furthermore, the shape of the outer case is arbitrary and can be any of the following: cylindrical, rectangular, laminated, coin-shaped, large, etc. [Examples]

[0128] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0129] The compounds used in this example are listed below. Compound (A): Vinyl ethylene sulfite

[0130] [ka]

[0131] Specific anionic compound: LiPO2F2: Lithium difluorophosphate Specific anionic compound: LiSO3F: Lithium fluorosulfonate ES: Ethylene sulfite

[0132] <Examples 1-3, Comparative Examples 1-4> (Preparation of non-aqueous electrolyte) Under a dry argon atmosphere, thoroughly dried LiPF6 was dissolved in a mixture of ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate (volume ratio 3:4:3) to a non-aqueous electrolyte solution with a concentration of 1.2 mol / L (14.5 mass%). In this non-aqueous electrolyte solution, vinylene carbonate was dissolved to a concentration of 2 mass%, and monofluoroethylene carbonate was dissolved to a concentration of 2 mass%. Furthermore, vinylethylene sulfite, as compound (A), was dissolved in the non-aqueous electrolyte solution to the concentrations shown in Table 1. In addition, in Examples 2 and 3, and Comparative Example 2, LiPO2F2, LiSO3F, and ES were dissolved in the non-aqueous electrolyte solution to the concentrations shown in Table 1, respectively, to prepare non-aqueous electrolyte solutions. Compound (A) was not used in Comparative Examples 1 to 3. Using this non-aqueous electrolyte solution, a non-aqueous electrolyte secondary battery was prepared by the following method.

[0133] (Fabrication of the positive electrode) Lithium cobalt nickel manganese oxide (Li) is used as the positive electrode active material. 1.05 Ni 0.34 Co 0.33 Mn 0.33 85 parts by mass of O2, 10 parts by mass of acetylene black as a conductive material, and 5 parts by mass of polyvinylidene fluoride (PVdF) as a binder were mixed in N-methyl-2-pyrrolidone to form a slurry. This slurry was uniformly applied to a 15 μm thick aluminum foil, dried, and then roll-pressed to form the positive electrode. The density of the positive electrode active material layer in the positive electrode was 2.6 g / cm³. 3 That was the case.

[0134] (Fabrication of negative electrode 1) Si nanoparticles with an average particle size of 50 nm were dispersed in flaky graphite with an average particle size of 35 μm. This mixture was placed in a hybridization system (manufactured by Nara Machine Works Co., Ltd.) and processed by circulating or retaining the mixture in the apparatus at a rotor speed of 7000 rpm for 180 seconds to obtain a composite of Si nanoparticles and graphite particles. The obtained composite was mixed with coal tar pitch as an organic compound that would be carbon-based, so that the coverage rate after calcination would be 16.8%, and then kneaded and dispersed using a twin-screw kneader. The resulting dispersion was introduced into a calcination furnace and calcined at 1000°C for 3 hours under a nitrogen atmosphere. The resulting calcined material was further pulverized with a hammer mill and then separated using a sieve (45 μm) to prepare the negative electrode active material. The Si element content in the negative electrode active material was 14.0 mass%.

[0135] To the anode active material (a mixture of the anode active material and graphite prepared above, with a mass ratio of anode active material to graphite of 35:65), aqueous dispersion of sodium carboxymethylcellulose as a thickener (1% by mass of sodium carboxymethylcellulose) and aqueous dispersion of styrene-butadiene rubber as a binder (50% by mass of styrene-butadiene rubber) were added and mixed in a disperser to form a slurry. This slurry was uniformly applied to one side of a 10 μm thick copper foil, dried, and then pressed to form anode 1. After drying, the mass ratio of anode active material:sodium carboxymethylcellulose:styrene-butadiene rubber was 97.5:1.5:1.

[0136] (Fabrication of negative electrode 2) To natural graphite, an aqueous dispersion of sodium carboxymethylcellulose (1% by mass of sodium carboxymethylcellulose) was added as a thickener, and an aqueous dispersion of styrene-butadiene rubber (50% by mass of styrene-butadiene rubber) was added as a binder. The mixture was then mixed in a disperser to form a slurry. The resulting slurry was applied to one side of a 10 μm thick copper foil, dried, and then pressed to form the negative electrode. After drying, the mass ratio of the negative electrode active material to sodium carboxymethylcellulose to styrene-butadiene rubber was 98:1:1.

[0137] (Manufacturing of non-aqueous electrolyte secondary batteries) The positive and negative electrodes and polyolefin separators prepared as described above were stacked in the order of negative electrode, separator, and positive electrode. The resulting battery elements were wrapped in an aluminum laminate film, injected with the aforementioned non-aqueous electrolyte, and then vacuum-sealed to produce a sheet-like non-aqueous electrolyte secondary battery. The negative electrode used was the one described in Table 1.

[0138] [Evaluation of non-aqueous electrolyte secondary batteries] The non-aqueous electrolyte secondary battery prepared as described above was evaluated as follows. (Initial charge / discharge) A sheet-shaped non-aqueous electrolyte secondary battery was charged at a constant current equivalent to 0.05C for 6 hours in a constant temperature bath at 25°C, and then discharged at a constant current of 0.2C to 3V. Furthermore, the non-aqueous electrolyte secondary battery was stabilized by constant-current-low-voltage charging (hereinafter also referred to as "CC-CV charging") at 0.2C up to 4.1V, followed by storage at 60°C for 24 hours. Subsequently, at 25°C, it was discharged at 0.2C down to 3V with constant current, and then CC-CV charging was performed at 0.2C up to a voltage of 4.2V. After that, it was discharged at 0.2C down to 3V with constant current, and then CC-CV charging was performed at 0.2C up to a voltage of 3.75V. Finally, the thickness of the electrode portion of the sheet-shaped non-aqueous electrolyte secondary battery was measured and determined as the initial electrode thickness. Here, 1C represents the current value required to discharge the battery's standard capacity in one hour. For example, 0.025C represents 1 / 40th of that current value. The same applies to subsequent values.

[0139] [Evaluation of cycle capacity retention rate, electrode swelling, and resistance after cycling] The non-aqueous electrolyte secondary batteries, after the initial charge and discharge described above, were subjected to constant current discharge at 0.2C to 2.5V in a constant temperature bath at 45°C. Subsequently, CC-CV charging was performed at 0.2C to a voltage of 4.2V, followed by constant current discharge at 0.2C to 2.5V, and the discharge capacity at this time was defined as the "initial capacity". Subsequently, the battery was charged using CC-CV at 1C to a voltage of 4.2V at 45°C, and then discharged at 1C to a constant current of 2.5V, repeating this process 200 times. After that, CC-CV charging was performed at 0.2C to a voltage of 4.2V, and then discharged at 0.2C to a constant current of 2.5V. The discharge capacity at this point was defined as the "capacity after 200 cycles." The ratio of the initial capacity to the capacity after 200 cycles was defined as the "cycle capacity retention rate." Subsequently, CC-CV charging was performed at 0.2C until the voltage reached 3.75V, and the thickness of the electrode portion of the sheet-shaped non-aqueous electrolyte secondary battery was measured. The difference from the initial electrode thickness was defined as "electrode swelling." Furthermore, constant current discharge was performed at 25°C at 0.15C, 0.2C, 0.75C, and 1C, and the voltage after 10 seconds was measured. The internal resistance was determined from this current-voltage line and defined as the "resistance after the cycle."

[0140] Table 1 shows the cycle capacity retention rate, electrode swelling, and post-cycle resistance of the examples and comparative examples (relative values ​​for lithium batteries using each negative electrode, with lithium-ion batteries (Comparative Example 1 or 3) in which the non-aqueous electrolyte does not contain compound (A) and other compounds set to 100).

[0141] [Table 1]

[0142] As is clear from Table 1, the non-aqueous electrolyte secondary battery (Example 1) comprises a non-aqueous electrolyte containing compound (A) and a negative electrode 1 having a silicon-containing negative electrode active material. (a) A non-aqueous electrolyte secondary battery (Comparative Example 1) comprising a non-aqueous electrolyte that does not contain compound (A) and a negative electrode 1, and (b) Compared to a non-aqueous electrolyte secondary battery (Comparative Example 2) comprising a non-aqueous electrolyte containing ES, which is used in the conventional technology, instead of compound (A), and a negative electrode 1, the capacity retention rate after cycle charging and discharging was improved, and electrode swelling and resistance after cycling were suppressed. Furthermore, the non-aqueous electrolyte secondary batteries (Examples 2-3), which comprise a non-aqueous electrolyte containing compound (A) and a specific amount of a specific additive, and a negative electrode 1 having a silicon-containing negative electrode active material, showed an even higher level of capacity retention after cycle charging and discharging compared to the non-aqueous electrolyte secondary battery of Example 1, and showed suppressed electrode swelling and resistance after cycling. On the other hand, a non-aqueous electrolyte secondary battery (Comparative Example 4) equipped with a non-aqueous electrolyte containing compound (A) and a negative electrode 2 containing a silicon-free negative electrode active material showed a worse capacity retention rate after cycle charging and discharging, increased electrode swelling, and no improvement in resistance after cycling compared to a non-aqueous electrolyte secondary battery (Comparative Example 3) equipped with a non-aqueous electrolyte not containing compound (A) and a negative electrode 2 containing a silicon-free negative electrode active material. In other words, in a non-aqueous electrolyte secondary battery equipped with a negative electrode 2 containing a silicon-free negative electrode active material, when a non-aqueous electrolyte containing compound (A) was used, the capacity retention rate after cycle charging and discharging decreased rather than improved, electrode swelling worsened rather than was suppressed, and no improvement in resistance after cycling was observed. From this, it can be seen that the effect of improving the capacity retention rate after cycle charging and discharging and suppressing electrode swelling and resistance after cycling, as shown in the examples, is a unique effect obtained when a non-aqueous electrolyte containing compound (A) is used in a non-aqueous electrolyte secondary battery equipped with a negative electrode containing a negative electrode active material containing a metallic element and / or metalloid element that can be alloyed with Li, such as silicon. Furthermore, based on the results from the non-aqueous electrolyte secondary battery of Example 1 and the non-aqueous electrolyte secondary battery of Comparative Example 4, it is believed that the effects of the present invention are obtained because compound (A) containing a carbon-carbon unsaturated bond reacts on the Si surface to form a protective film, and further sulfur atoms are reduced to form an anionic film, thereby promoting Li conduction in the film, suppressing overvoltage during charging and discharging, and suppressing degradation of Si particles and electrolyte decomposition reactions on the Si surface. [Industrial applicability]

[0143] The non-aqueous electrolyte battery of the present invention, when used in non-aqueous electrolyte batteries, improves the capacity retention rate after cycle charging and discharging, and suppresses electrode swelling and resistance after cycling. Therefore, the non-aqueous electrolyte battery of the present invention can be suitably used in all fields, such as electronic devices, where non-aqueous electrolyte batteries have conventionally been used. Furthermore, the non-aqueous electrolyte battery of the present invention can be used in various known applications. Specific examples of applications include, for example, notebook computers, pen-input computers, mobile computers, e-book players, mobile phones, portable fax machines, portable copiers, portable printers, portable audio players, mini video cameras, headphone stereos, video camcorders, LCD televisions, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, strobes, cameras, household backup power supplies, business backup power supplies, load leveling power supplies, and renewable energy storage power supplies.

Claims

1. A non-aqueous electrolyte for a non-aqueous electrolyte battery, comprising a negative electrode having a negative electrode active material containing a metallic element and / or a metalloid element that can be alloyed with Li, The aforementioned non-aqueous electrolyte contains compound (A) represented by the following formula (II), The non-aqueous electrolyte contains 0.01% by mass or more and 10% by mass or less of the compound (A), The non-aqueous electrolyte is characterized in that it contains 0.001% by mass or more and 5% by mass or less of one or more anion-containing compounds selected from the group consisting of phosphate anion-containing compounds having P-F bonds and P=O bonds and anion-containing compounds having S=O bonds in the non-aqueous electrolyte. 【Chemistry 1】 (In formula (II), R1 and R2 are each independently selected from a hydrogen atom, a halogen atom, a vinyl group, and an allyl group, and either R1 or R2 is selected from a vinyl group and an allyl group.)

2. The non-aqueous electrolyte according to claim 1, wherein the mass ratio of the total content of the phosphate anion-containing compound having P-F bonds and P=O bonds and the anion-containing compound having S=O bonds to the content of compound (A) (total content of phosphate anion-containing compound having P-F bonds and P=O bonds and the anion-containing compound having S=O bonds / content of compound (A)) is 0.01 or more and 100 or less.

3. Furthermore, the non-aqueous electrolyte according to claim 1 or 2, wherein at least one carbonate compound selected from cyclic carbonates having carbon-carbon unsaturated bonds and fluorine-containing cyclic carbonates is contained in the non-aqueous electrolyte in an amount of 0.001% by mass or more and 10% by mass or less.

4. The non-aqueous electrolyte according to claim 3, wherein the mass ratio of the total content of at least one carbonate compound selected from the cyclic carbonate having carbon-carbon unsaturated bonds and the fluorine-containing cyclic carbonate to the content of compound (A) (total content of cyclic carbonate having carbon-carbon unsaturated bonds and the fluorine-containing cyclic carbonate / content of compound (A)) is 0.01 or more and 100 or less.

5. A non-aqueous electrolyte battery comprising a non-aqueous electrolyte, a positive electrode having a positive electrode active material, and a negative electrode having a negative electrode active material, The non-aqueous electrolyte is the non-aqueous electrolyte according to claim 1 or 2. A non-aqueous electrolyte battery characterized in that the negative electrode active material contains a material containing a metallic element and / or a metalloid element that can be alloyed with Li.

6. The non-aqueous electrolyte battery according to claim 5, wherein the negative electrode active material contains the element Si.

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