Non-aqueous secondary batteries

Abstract

A non-aqueous secondary battery is provided, comprising: a positive electrode containing one or more positive electrode active materials capable of absorbing and releasing lithium ions; a negative electrode containing at least one negative electrode active material selected from the group consisting of a material capable of absorbing and releasing lithium ions and metallic lithium; and a non-aqueous electrolyte, wherein the negative electrode contains at least one compound selected from the group consisting of compounds represented by the following general formulas (1) to (3).

Description

Technical Field

[0001] The present invention relates to a non-aqueous secondary battery. Background Art

[0002] Non-aqueous secondary batteries, such as lithium-ion batteries, offer advantages such as lightweight, high energy, and long life, making them widely used as power sources for various portable electronic devices. In recent years, non-aqueous secondary batteries have also seen an expansion in industrial applications, such as power tools, and in vehicles such as electric vehicles and electric bicycles. Furthermore, they are attracting attention in power storage applications, such as residential energy storage systems.

[0003] In particular, concerns about global warming and fossil fuel depletion have led to a desire for non-aqueous secondary batteries to be applied to the large-scale energy storage industry, centered around electric vehicles. However, the widespread adoption of electric vehicles is driving the need for further higher output and higher energy density in non-aqueous secondary batteries. To achieve these performance requirements, research and development efforts are underway to improve the energy density of active materials for both the positive and negative electrodes.

[0004] Patent Document 1 describes the following: specifying the optimal LUMO energy range and HOMO energy range of the anion of the organic lithium salt and combining multiple additives are preferred from the perspective of the durability of the SEI (solid electrolyte interface) on the negative electrode surface. Patent Document 2 also describes the following: combining a specific lithium salt with multiple additives is preferred from the perspective of the durability of the SEI (solid electrolyte interface) on the negative electrode surface.

[0005] Patent Document 3 reports that by designing the porosity of composite particles constituting the electrode material within an optimal range, electrode degradation caused by repeated expansion and contraction of a high-capacity negative electrode can be suppressed. Patent Document 4 reports that by designing the thickness of the negative electrode active material to be no more than twice the average particle size of the negative electrode active material particles, the increase in resistance caused by repeated expansion and contraction of the negative electrode can be suppressed.

[0006] Patent Document 5 describes that the addition of an additive can suppress degradation of battery performance caused by repeated expansion and contraction of a high-capacity negative electrode.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: International Publication No. 12 / 057311

[0010] Patent Document 2: International Publication No. 13 / 062056

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2003-303588

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 2004-146104

[0013] Patent Document 5: International Publication No. 17 / 077986 Summary of the Invention

[0014] Problems to be solved by the invention

[0015] If the negative electrode coating is not sufficiently resistant to the solubility of the non-aqueous electrolyte, it may dissolve during various tests under high temperature environments. In this case, the dissolved portion will cause the non-aqueous electrolyte to undergo reductive decomposition, resulting in gas generation and capacity reduction.

[0016] Here, Patent Documents 1 and 2 focus on the formation of a protective film resistant to dissolution of a non-aqueous electrolyte (formation of a protective film in the negative electrode). In other words, the inventions described in Patent Documents 1 and 2 are inventions that can function as a non-aqueous electrolyte if the reductive decomposition of the non-aqueous electrolyte in the negative electrode can be resolved.

[0017] However, when using the negative electrodes described in Patent Documents 3 and 4, the active material itself expands and contracts significantly with charge and discharge cycles. Consequently, repeated charge and discharge cycles can cause defects in the initially formed protective coating, leading to reductive decomposition of the non-aqueous electrolyte and deterioration of battery performance. Therefore, when using the electrolytes described in Patent Documents 1 and 2 with negative electrode materials that expand and contract significantly, the negative electrode protective coating must not only have excellent dissolution resistance but also excellent physical strength.

[0018] On the other hand, when the additive described in Patent Document 5 is used, the durability against expansion and contraction of the negative electrode tends to be improved, but the dissolution resistance to the electrolyte solution tends to be insufficient.

[0019] In addition to the above, in recent years, further suppression of various degradations during charge and discharge cycles has been desired for non-aqueous secondary batteries.

[0020] The present invention has been proposed in view of the above-mentioned problems, and its object is to provide a non-aqueous secondary battery that can exhibit excellent load characteristics and output performance and suppress various deterioration phenomena during high-temperature storage or charge and discharge cycles in low-temperature and high-temperature environments by providing a coating on the surface of the electrode active material that not only has excellent dissolution resistance to non-aqueous electrolytes but also has excellent physical strength.

[0021] Solutions for solving problems

[0022] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have discovered that the above-mentioned problems can be solved by using a non-aqueous secondary battery having the following structure. Specifically, the embodiments of the present invention are described below.

[0023] [1] A non-aqueous secondary battery comprising:

[0024] A positive electrode containing one or more positive electrode active materials capable of absorbing and releasing lithium ions;

[0025] a negative electrode containing at least one negative electrode active material selected from the group consisting of a material capable of occluding and releasing lithium ions, and metallic lithium; and

[0026] Non-aqueous electrolyte,

[0027] The negative electrode contains at least one compound selected from the group consisting of compounds represented by the following general formula (1), the following general formula (2), and the following general formula (3).

[0028]

[0029]

[0030] [2] The non-aqueous secondary battery according to [1], wherein the total content of the compounds represented by the general formulae (2) and (3) is 0.01 to 2.5 mg per 1 g of the negative electrode active material.

[0031] [3] The non-aqueous secondary battery according to [1] or [2], wherein the content of at least one compound selected from the group consisting of compounds represented by the aforementioned general formulae (1) to (3) is 0.01 to 100 mg per 1 g of the negative electrode active material.

[0032] [4] The non-aqueous secondary battery according to any one of [1] to [3], wherein the non-aqueous electrolyte solution contains acetonitrile.

[0033] [5] The non-aqueous secondary battery according to [4], wherein the content of the acetonitrile is 5% by mass or more and 95% by mass or less relative to the total amount of the non-aqueous electrolyte solution.

[0034] [6] The non-aqueous secondary battery according to any one of [1] to [5], wherein the non-aqueous electrolyte solution contains a fluorine-containing lithium salt.

[0035] [7] The non-aqueous secondary battery according to any one of [1] to [6], wherein the non-aqueous electrolyte contains LiN(SO2C m F 2m+1 )2{wherein, m is an integer of 0 to 8} represented by an imide salt.

[0036] [8] The non-aqueous secondary battery according to any one of [1] to [7], wherein the negative electrode contains PF6 anions.

[0037] [9] The non-aqueous secondary battery according to any one of [1] to [8], wherein the negative electrode contains N(SO2F)2 anions and / or N(SO2CF3)2 anions.

[0038]

[10] The non-aqueous secondary battery according to any one of [1] to [9], wherein the negative electrode contains a decomposition product of a cyclic acid anhydride.

[0039]

[11] The non-aqueous secondary battery according to

[10] , wherein the decomposition product of the cyclic acid anhydride contains at least one compound selected from the group consisting of compounds represented by the following general formula (4), the following general formula (5), the following general formula (6), the following general formula (7), the following general formula (8) and the following general formula (9).

[0040]

[0041] {In general formula (4), R 6 and R 7 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom, and f is an integer of 1 to 3,}

[0042]

[0043] {In general formula (5), R 8 and R 9 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom,}

[0044]

[0045] {In general formula (6), R 10 and R 11 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom,}

[0046]

[0047] {In general formula (7), R 12 and R 13 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom,}

[0048]

[0049] {In general formula (8), R 14 and R 15represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom,}

[0050]

[0051] {In general formula (9), R 16 ~R 19 represents an alkoxy group, an OH group or an OLi group which may be substituted by a halogen atom.}

[0052]

[12] The non-aqueous secondary battery according to

[10] or

[11] , wherein the cyclic acid anhydride contains at least one selected from the group consisting of malonic anhydride, succinic anhydride, glutaric anhydride, maleic anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 2,3-naphthalene dicarboxylic anhydride and naphthalene-1,4,5,8-tetracarboxylic dianhydride.

[0053]

[13] The non-aqueous secondary battery according to any one of claims [1] to

[12] , wherein the non-aqueous electrolyte solution contains a non-aqueous solvent, and the non-aqueous solvent contains a cyclic carbonate.

[0054]

[14] The non-aqueous secondary battery according to

[13] , wherein the cyclic carbonate contains vinylene carbonate and / or fluoroethylene carbonate.

[0055]

[15] The non-aqueous secondary battery according to any one of [1] to

[14] , wherein the negative electrode active material contains at least one element capable of forming an alloy with lithium.

[0056]

[16] The non-aqueous secondary battery according to any one of [1] to

[15] , wherein the negative electrode active material contains silicon.

[0057]

[17] The non-aqueous secondary battery according to any one of [1] to

[16] , wherein the ion conductivity of the non-aqueous electrolyte at 20°C is 15 mS / cm or higher.

[0058]

[18] The non-aqueous secondary battery according to any one of [1] to

[17] , wherein the separator used in the non-aqueous secondary battery has a thickness of 3 μm or more and 25 μm or less.

[0059]

[19] The non-aqueous secondary battery according to any one of [1] to

[18] , wherein the porosity of the separator used in the non-aqueous secondary battery is 40% or more and 70% or less.

[0060]

[20] The non-aqueous secondary battery according to any one of [1] to

[19] , wherein the separator used in the non-aqueous secondary battery has an air permeability of 100 s / 100 cm 3Above 350s / 100cm 3 the following.

[0061]

[21] The non-aqueous secondary battery according to any one of [1] to

[20] , wherein the non-aqueous electrolyte contains at least one nitric acid compound selected from the group consisting of nitrates and nitrate esters.

[0062]

[22] A non-aqueous secondary battery according to any one of [1] to

[21] , wherein the non-aqueous electrolyte contains at least one additive selected from the group consisting of a polymer compound containing a repeating unit represented by any of the following general formula (P1), the following general formula (P2), the following general formula (P3) and the following general formula (P4), and a carboxylic acid ester compound.

[0063]

[0064] {In the general formula (P1), R1 is a hydrogen atom or an alkyl group,}

[0065]

[0066] {In general formula (P2), n1 to n3 are the number of repeating units, each independently being an integer from 0 to 4,}

[0067]

[0068] {In the general formula (P3), R2 is an alkyl group having 1 to 20 carbon atoms or a fluoroalkyl group having 1 to 20 carbon atoms,}

[0069]

[0070] {In the general formula (P4), R3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.}

[0071]

[23] The non-aqueous secondary battery according to any one of [1] to

[22] , wherein the non-aqueous electrolyte contains at least one additive selected from the group consisting of organic metal hydrides and dicarbonate compounds.

[0072]

[24] The non-aqueous secondary battery according to any one of [1] to

[23] , wherein the non-aqueous electrolyte solution contains a silyl group-containing additive.

[0073]

[25] The non-aqueous secondary battery according to any one of [1] to

[24] , wherein the non-aqueous electrolyte solution contains an additive containing a boron atom.

[0074]

[26] A non-aqueous electrolyte comprising a non-aqueous solvent and a lithium salt,

[0075] The non-aqueous solvent contains 5% by mass or more and 95% by mass or less of acetonitrile relative to the total amount of the non-aqueous solvent, and

[0076] The non-aqueous electrolyte solution further contains at least one nitric acid compound selected from the group consisting of nitrates and nitrate esters.

[0077]

[27] A non-aqueous electrolyte comprising a non-aqueous solvent and a lithium salt,

[0078] The non-aqueous solvent contains 5% by mass or more and 95% by mass or less of acetonitrile relative to the total amount of the non-aqueous solvent, and

[0079] The non-aqueous electrolyte further contains at least one additive selected from the group consisting of a polymer compound containing a repeating unit represented by any of the following general formula (P1), the following general formula (P2), the following general formula (P3), and the following general formula (P4), and a carboxylic acid ester compound.

[0080]

[0081] {In the general formula (P1), R1 is a hydrogen atom or an alkyl group,}

[0082]

[0083] {In general formula (P2), n1 to n3 are the number of repeating units, each independently being an integer from 0 to 4,}

[0084]

[0085] {In the general formula (P3), R2 is an alkyl group having 1 to 20 carbon atoms or a fluoroalkyl group having 1 to 20 carbon atoms,}

[0086]

[0087] {In the general formula (P4), R3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.}

[0088]

[28] A non-aqueous electrolyte comprising a non-aqueous solvent and a lithium salt,

[0089] The non-aqueous solvent contains 5% by mass or more and 95% by mass or less of acetonitrile relative to the total amount of the non-aqueous solvent, and

[0090] The non-aqueous electrolyte solution further contains at least one additive selected from the group consisting of organometallic hydrides and dicarbonate compounds.

[0091]

[29] A non-aqueous electrolyte comprising a non-aqueous solvent and a lithium salt,

[0092] The non-aqueous solvent contains 5% by mass or more and 95% by mass or less of acetonitrile relative to the total amount of the non-aqueous solvent, and

[0093] The non-aqueous electrolyte solution further includes a silyl group-containing additive.

[0094]

[30] A non-aqueous electrolyte comprising a non-aqueous solvent and a lithium salt,

[0095] The non-aqueous solvent contains 5% by mass or more and 95% by mass or less of acetonitrile relative to the total amount of the non-aqueous solvent, and

[0096] The non-aqueous electrolyte further includes an additive containing a boron atom.

[0097] Effects of the Invention

[0098] According to the non-aqueous secondary battery of the present invention, by providing a coating on the surface of the electrode active material that not only has excellent dissolution resistance to non-aqueous electrolytes but also has excellent physical strength, it can exhibit excellent load characteristics and output performance and suppress various deterioration phenomena during high-temperature storage or charge and discharge cycles in low-temperature and high-temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Figure 1 It is a plan view schematically showing an example of the non-aqueous secondary battery according to the present embodiment.

[0100] Figure 2 for Figure 1 AA line cross-sectional view of a non-aqueous secondary battery. DETAILED DESCRIPTION

[0101] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail. The present invention is not limited to the following embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0102] Non-aqueous electrolytes

[0103] The "non-aqueous electrolyte" in the present embodiment refers to an electrolyte in which water is less than 1% by mass relative to the total amount of the non-aqueous electrolyte. The non-aqueous electrolyte in the present embodiment preferably does not contain water as much as possible, but may contain extremely small amounts of water within a range that does not hinder the solution of the problem of the present invention. The content of such water is less than 300 mass ppm, preferably less than 200 mass ppm, relative to the total amount of the non-aqueous electrolyte. For the non-aqueous electrolyte, if it has a structure for achieving the solution of the problem of the present invention, for other constituent elements, the constituent materials of the known non-aqueous electrolyte used in lithium-ion batteries can be appropriately selected for application.

[0104] The non-aqueous electrolyte solution in this embodiment may contain a non-aqueous solvent and a lithium salt. In addition, the non-aqueous electrolyte solution in this embodiment may further contain various additives.

[0105] 〈Non-aqueous solvents〉

[0106] The "non-aqueous solvent" in this embodiment refers to the elements in the non-aqueous electrolyte other than the lithium salt and various additives. Examples of the non-aqueous solvent include alcohols such as methanol and ethanol; aprotic solvents; and the like. Among them, the non-aqueous solvent is preferably an aprotic solvent (aprotic polar solvent). The non-aqueous solvent may contain solvents other than aprotic solvents as long as it does not hinder the solution of the problem of the present invention.

[0107] For example, the non-aqueous solvent may contain acetonitrile as an aprotic solvent. By containing acetonitrile in the non-aqueous solvent, the rapid charging characteristics of the non-aqueous secondary battery can be improved. In the constant current (CC)-constant voltage (CV) charging of the non-aqueous secondary battery, the capacity per unit time during the CC charging period is larger than the charging capacity per unit time during the CV charging period. When acetonitrile is used as the non-aqueous solvent of the non-aqueous electrolyte, in addition to increasing the area in which CC charging can be performed (extending the time of CC charging), the charging current can also be increased, thereby significantly shortening the time from the start of charging of the non-aqueous secondary battery to the formation of a fully charged state.

[0108] Acetonitrile is easily reductively decomposed electrochemically. Therefore, when using acetonitrile, it is preferably used as a non-aqueous solvent, combined with another solvent (e.g., an aprotic solvent other than acetonitrile), and / or with a predetermined additive.

[0109] The content of acetonitrile is preferably 5 to 95% by volume relative to the total amount of the non-aqueous solvent. The content of acetonitrile is more preferably 20% by volume or more or 30% by volume or more, and more preferably 40% by volume or more, relative to the total amount of the non-aqueous solvent. This value is more preferably 85% by volume or less, and more preferably 66% by volume or less. When the content of acetonitrile is 5% by volume or more relative to the total amount of the non-aqueous solvent, there is a tendency that the ionic conductivity increases and high output characteristics can be exhibited, thereby promoting the dissolution of the lithium salt. Since the additives described later suppress the increase in the internal resistance of the battery, when the content of acetonitrile in the non-aqueous solvent is within the above range, there is a tendency that the charge and discharge cycle characteristics and other battery characteristics can be further improved while maintaining the excellent performance of acetonitrile.

[0110] Examples of aprotic solvents other than acetonitrile include cyclic carbonates, fluoroethylene carbonate, lactones, organic compounds having S atoms, chain carbonates, cyclic ethers, mononitriles other than acetonitrile, alkoxy-substituted nitriles, dinitriles, cyclic nitriles, short-chain fatty acid esters, chain ethers, fluorinated ethers, ketones, and compounds in which some or all of the H atoms of the above compounds are substituted with halogen atoms.

[0111] Examples of the cyclic carbonate include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, trans-2,3-butylene carbonate, cis-2,3-butylene carbonate, 1,2-pentylene carbonate, trans-2,3-pentylene carbonate, cis-2,3-pentylene carbonate, vinylene carbonate, 4,5-dimethylvinylene carbonate, and vinylethylene carbonate;

[0112] Examples of the fluoroethylene carbonate include 4-fluoro-1,3-dioxolane-2-one, 4,4-difluoro-1,3-dioxolane-2-one, cis-4,5-difluoro-1,3-dioxolane-2-one, trans-4,5-difluoro-1,3-dioxolane-2-one, 4,4,5-trifluoro-1,3-dioxolane-2-one, 4,4,5,5-tetrafluoro-1,3-dioxolane-2-one, and 4,4,5-trifluoro-5-methyl-1,3-dioxolane-2-one.

[0113] Examples of lactones include γ-butyrolactone, α-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone, δ-caprolactone, and ε-caprolactone;

[0114] Examples of the organic compound having a sulfur atom include ethylene sulfite, propylene sulfite, butylene sulfite, pentenyl sulfite, sulfolane, 3-sulfolane, 3-methylsulfolane, 1,3-propane sultone, 1,4-butane sultone, 1-propylene 1,3-sultone, dimethyl sulfoxide, tetramethylene sulfoxide, and ethylene glycol sulfite;

[0115] Examples of the chain carbonate include ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, and ethyl propyl carbonate;

[0116] Examples of the cyclic ether include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, and 1,3-dioxane;

[0117] Examples of mononitriles other than acetonitrile include propionitrile, butyronitrile, valeronitrile, benzonitrile, and acrylonitrile;

[0118] As alkoxy-substituted nitriles, for example, methoxyacetonitrile and 3-methoxypropionitrile can be mentioned;

[0119] Examples of the dinitriles include malononitrile, succinonitrile, glutaronitrile, adiponitrile, 1,4-dicyanoheptane, 1,5-dicyanopentane, 1,6-dicyanohexane, 1,7-dicyanoheptane, 2,6-dicyanoheptane, 1,8-dicyanooctane, 2,7-dicyanooctane, 1,9-dicyanononane, 2,8-dicyanononane, 1,10-dicyanodecane, 1,6-dicyanodecane, and 2,4-dimethylglutaronitrile.

[0120] Examples of the cyclic nitrile include benzonitrile;

[0121] Examples of the short-chain fatty acid esters include methyl acetate, methyl propionate, methyl isobutyrate, methyl butyrate, methyl isovalerate, methyl valerate, methyl pivalate, methyl hydroangelate, methyl hexanoate, ethyl acetate, ethyl propionate, ethyl isobutyrate, ethyl butyrate, ethyl isovalerate, ethyl valerate, ethyl pivalate, ethyl hydroangelate, ethyl hexanoate, propyl acetate, propyl propionate, propyl isobutyrate, propyl butyrate, propyl isovalerate, propyl valerate, propyl pivalate, propyl hydroangelate, propyl hexanoate, isopropyl acetate, isopropyl propionate, isopropyl isobutyrate, isopropyl butyrate, isopropyl isovalerate, isopropyl valerate, isopropyl pivalate, isopropyl hydroangelate, isopropyl hexanoate, butyl acetate, butyl propionate, butyl isobutyrate, butyl butyrate, butyl isovalerate, butyl valerate, butyl pivalate, butyl hydroangelate, butyl hexanoate, isobutyl acetate, isobutyl propionate, isobutyl isobutyrate, isobutyl butyrate, isobutyl isovalerate, isobutyl valerate, isobutyl pivalate, isobutyl hydroangelate, isobutyl hexanoate, tert-butyl acetate, tert-butyl propionate, tert-butyl isobutyrate, tert-butyl butyrate, tert-butyl isovalerate, tert-butyl valerate, tert-butyl pivalate, tert-butyl hydroangelate, and tert-butyl hexanoate;

[0122] Examples of the chain ether include dimethoxyethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme, and tetraglyme;

[0123] Examples of the fluorinated ether include Rf 20 -OR 21 (Rf 20 is an alkyl group containing a fluorine atom, R 7 is an organic group which may contain a fluorine atom);

[0124] Examples of ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone;

[0125] Examples of the compounds in which a part or all of the H atoms in the above-mentioned compounds are substituted with halogen atoms include compounds in which the halogen atoms are fluorine.

[0126] Here, examples of the fluorinated chain carbonate include trifluoroethyl methyl carbonate, trifluorodimethyl carbonate, trifluorodiethyl carbonate, trifluoroethyl methyl carbonate, 2,2-difluoroethyl methyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, and 2,2,3,3-tetrafluoropropyl methyl carbonate. The fluorinated chain carbonate can be represented by the following general formula:

[0127] R 29 -OC(O)OR 30

[0128] (Where R 29 and R 30 is selected from CH3, CH2CH3, CH2CH2CH3, CH(CH3)2, and CH2Rf 31 At least one of the group consisting of 31 is an alkyl group having 1 to 3 carbon atoms in which at least one fluorine atom replaces a hydrogen atom, and R 29 and / or R 30 containing at least one fluorine atom).

[0129] Examples of fluorinated short-chain fatty acid esters include fluorinated short-chain fatty acid esters represented by 2,2-difluoroethyl acetate, 2,2,2-trifluoroethyl acetate, and 2,2,3,3-tetrafluoropropyl acetate.

[0130] R 32 -C(O)OR 33

[0131] (Where R 32 is selected from CH3, CH2CH3, CH2CH2CH3, CH(CH3)2, CF3CF2H, CFH2, CF2Rf 34 CFHRf 34 , and CH2Rf 35 At least one of the group consisting of R 33 is selected from CH3, CH2CH3, CH2CH2CH3, CH(CH3)2, and CH2Rf 35 At least one of the group consisting of 34 is an alkyl group having 1 to 3 carbon atoms in which at least one fluorine atom replaces a hydrogen atom, Rf 35 is an alkyl group having 1 to 3 carbon atoms in which at least one fluorine atom replaces a hydrogen atom, and R 32 and / or R 33Contains at least one fluorine atom, R 32 In the case of CF2H, R 33 not CH3).

[0132] The aprotic solvents other than acetonitrile in the present embodiment may be used alone or in combination of two or more.

[0133] The non-aqueous solvent in the present embodiment, considers from the viewpoint that the stability of non-aqueous electrolyte improves, preferably uses in combination more than a kind in cyclic carbonate and the linear carbonate when using acetonitrile.Considered from this viewpoint, the non-aqueous solvent in the present embodiment more preferably uses in combination cyclic carbonate, further preferably uses in combination cyclic carbonate and the linear carbonate when using acetonitrile.

[0134] As the cyclic carbonate used in combination with acetonitrile, be preferably selected from at least one of the group consisting of ethylene carbonate, propylene carbonate, vinylene carbonate and fluoroethylene carbonate, more preferably selected from at least one of the group consisting of vinylene carbonate and fluoroethylene carbonate.The content of cyclic carbonate is in the amount relative to the total amount of non-aqueous solvent, preferably more than 0.5 mass % and below 50 mass %, more preferably more than 1 mass % and below 25 mass %.

[0135] As the linear carbonate used in combination with acetonitrile, be preferably selected from least a in the group consisting of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate.The content of linear carbonate is in the amount relative to the total amount of non-aqueous solvent, is preferably more than 5 mass % and below 50 mass %, more preferably more than 10 mass % and below 40 mass %.

[0136] Lithium salts

[0137] The non-aqueous electrolyte solution of this embodiment may contain a lithium salt.

[0138] The lithium salt in this embodiment is preferably LiN(SO2C m F 2m+1 )2{wherein, m is an integer of 0 to 8} represented by an imide salt.

[0139] The lithium salt in the present embodiment may contain an imide salt and at least one selected from fluorine-containing inorganic lithium salts, organic lithium salts, and other lithium salts.

[0140] (Imide salt)

[0141] Specifically, the imide salt preferably contains LiN(SO2F)2 and / or LiN(SO2CF3)2.

[0142] Since imide salts have relatively high decomposition temperatures, the inclusion of an imide salt as a lithium salt in a non-aqueous electrolyte suppresses resistance increases during high-temperature storage. Furthermore, the inclusion of an imide salt as a lithium salt in a non-aqueous electrolyte keeps the viscosity of the non-aqueous electrolyte low, thereby achieving excellent output performance, particularly in the low-temperature range.

[0143] The imide salt content is preferably 0.1 to 40% by mass, more preferably 0.2 to 30% by mass, and even more preferably 0.5 to 20% by mass relative to the total amount of the non-aqueous electrolyte. Within this range, the low-temperature performance of the non-aqueous electrolyte can be improved without reducing the ionic conductivity.

[0144] In addition, when the non-aqueous solvent contains acetonitrile, the saturation concentration of the imide salt with respect to acetonitrile is higher than the saturation concentration of LiPF6. Therefore, it is preferable to contain the imide salt at a molar concentration such that LiPF6 ≤ the imide salt, because this can suppress the binding and precipitation of the lithium salt and acetonitrile at low temperatures. In this case, the content of the imide salt is preferably 0.5 mol or more and 3.0 mol or less relative to 1 L of the non-aqueous solvent from the perspective of ensuring the ion supply to the non-aqueous electrolyte solution of this embodiment.

[0145] If a non-aqueous electrolyte containing acetonitrile and at least one of LiN(SO2F)2 and LiN(SO2CF3)2 is used, the decrease in ionic conductivity in a low temperature range such as -10°C or -30°C can be effectively suppressed, and excellent low temperature characteristics can be obtained.

[0146] (Fluorine-containing inorganic lithium salt)

[0147] The lithium salt in this embodiment may include a fluorine-containing inorganic lithium salt. "Fluorine-containing inorganic lithium salt" refers to a lithium salt that contains no carbon atoms in its anion, contains fluorine atoms in its anion, and is soluble in acetonitrile. Fluorine-containing inorganic lithium salts are excellent for forming a passive coating on the surface of the positive electrode current collector and inhibiting corrosion of the positive electrode current collector.

[0148] Examples of fluorine-containing inorganic lithium salts include LiPF6, LiBF4, LiAsF6, Li2SiF6, LiSbF6, Li2B 12 F b H 12-b {b is an integer of 0 to 3} etc., and one or more selected from these can be used.

[0149] As the fluorine-containing inorganic lithium salt, a compound that is a double salt of LiF and a Lewis acid is preferred. Among them, if a fluorine-containing inorganic lithium salt having a phosphorus atom is used, it is easy to release free fluorine atoms, so it is more preferred. A representative fluorine-containing inorganic lithium salt is LiPF6, which releases PF6 anions when dissolved. When a fluorine-containing inorganic lithium salt having a boron atom is used as the fluorine-containing inorganic lithium salt, it is easy to capture excess free acid components that may cause battery degradation, so it is preferred. From this point of view, LiBF4 is preferred.

[0150] The content of the fluorinated inorganic lithium salt in the non-aqueous electrolyte of this embodiment is preferably 0.01 mol or more, more preferably 0.1 mol or more, even more preferably 0.2 mol or more, and particularly preferably 0.25 mol or more, relative to 1 L of the non-aqueous solvent. When the content of the fluorinated inorganic lithium salt is within this range, there is a tendency for the ionic conductivity to increase, resulting in high output characteristics.

[0151] Furthermore, the amount relative to 1 L of the non-aqueous solvent is preferably 2.8 mol or less, more preferably 1.5 mol or less, and even more preferably 1.0 mol or less. When the content of the fluorinated inorganic lithium salt is within the above range, there is a tendency for the ionic conductivity to increase, thereby exhibiting high output characteristics, while suppressing the decrease in ionic conductivity associated with increased viscosity at low temperatures. This tends to further improve high-temperature cycle characteristics and other battery characteristics while maintaining the excellent performance of the non-aqueous electrolyte.

[0152] The content of the fluorine-containing inorganic lithium salt in the non-aqueous electrolyte solution of the present embodiment can be, for example, 0.05 mol or more and 1.0 mol or less relative to 1 L of the non-aqueous solvent.

[0153] (Organic lithium salt)

[0154] The lithium salt in this embodiment may include an organic lithium salt. "Organic lithium salt" refers to a lithium salt other than an imide salt containing a carbon atom in the anion and soluble in acetonitrile.

[0155] As the organic lithium salt, an organic lithium salt having an oxalic acid group can be cited. As a specific example of the organic lithium salt having an oxalic acid group, for example, organic lithium salts represented by LiB(C2O4)2, LiBF2(C2O4), LiPF4(C2O4), and LiPF2(C2O4)2 can be cited, among which at least one lithium salt selected from the lithium salts represented by LiB(C2O4)2 and LiBF2(C2O4) is preferred. In addition, it is more preferred to use one or more of them together with a fluorine-containing inorganic lithium salt. In addition to being added to a non-aqueous electrolyte, the organic lithium salt having an oxalic acid group can also be contained in the negative electrode (negative electrode active material layer).

[0156] From the perspective of better ensuring the effect achieved by its use, the amount of the organic lithium salt added to the non-aqueous electrolyte in this embodiment is preferably 0.005 mol or more, more preferably 0.01 mol or more, further preferably 0.02 mol or more, and particularly preferably 0.05 mol or more, based on the amount of the non-aqueous solvent 1L. However, if the amount of the organic lithium salt having an oxalic acid group in the non-aqueous electrolyte is too much, it is likely to precipitate. Therefore, the amount of the organic lithium salt having an oxalic acid group added to the non-aqueous electrolyte is preferably less than 1.0 mol, more preferably less than 0.5 mol, and further preferably less than 0.2 mol, based on the amount of the non-aqueous solvent 1L.

[0157] It is known that organic lithium salts having oxalic acid groups are poorly soluble in organic solvents with low polarity, particularly linear carbonates. The content of the organic lithium salt in the non-aqueous electrolyte solution of this embodiment can be, for example, 0.01 mol or more and 0.5 mol or less, based on the amount per liter of the non-aqueous solvent.

[0158] It should be noted that organic lithium salts having oxalate groups sometimes contain trace amounts of lithium oxalate. Furthermore, when mixed as a non-aqueous electrolyte, these salts may react with trace amounts of water contained in other raw materials to produce a new white precipitate of lithium oxalate. Therefore, the lithium oxalate content in the non-aqueous electrolyte of this embodiment is preferably suppressed to a range of 500 ppm or less.

[0159] (Other lithium salts)

[0160] The lithium salt in this embodiment may contain other lithium salts in addition to the above.

[0161] Specific examples of other lithium salts include

[0162] LiClO4, LiAlO4, LiAlCl4, LiB 10 Cl 10 , inorganic lithium salts whose anions do not contain fluorine atoms, such as chloroborane Li;

[0163] LiCF3SO3, LiCF3CO2, Li2C2F4(SO3)2, LiC(CF3SO2)3, LiC n F (2n+1) SO3 (n ≥ 2), lower aliphatic carboxylic acid Li, tetraphenylborate Li, LiB (C3O4H2) 2 and other organic lithium salts;

[0164] LiPF5(CF3) and other LiPF n (C p F 2p+1 ) 6-n An organic lithium salt represented by [n is an integer of 1 to 5, p is an integer of 1 to 8];

[0165] LiBF3(CF3) and other LiBF q (C s F 2s+1 ) 4-q [q is an integer of 1 to 3, s is an integer of 1 to 8]; an organic lithium salt represented by [q is an integer of 1 to 3, s is an integer of 1 to 8]; a lithium salt bonded to a polyvalent anion; an organic lithium salt represented by the following formula (15a), the following formula (15b), and the following formula (15c), respectively;

[0166] LiC(SO2R 22 )(SO2R 23 )(SO2R 24 )(15a)

[0167] {where R 22 、R 23 and R 24 They may be the same or different from each other and represent a perfluoroalkyl group having 1 to 8 carbon atoms.

[0168] LiN(SO2OR 25 )(SO2OR 26 )(15b)

[0169] {where R 25 and R 26 They may be the same or different from each other and represent a perfluoroalkyl group having 1 to 8 carbon atoms.

[0170] LiN(SO2R 27 )(SO2OR 28 )(15c)

[0171] {where R 27 and R 28 They may be the same or different and represent a perfluoroalkyl group having 1 to 8 carbon atoms.

[0172] One or more of these may be used together with the fluorine-containing inorganic lithium salt.

[0173] The amount of other lithium salt added to the non-aqueous electrolyte solution can be appropriately set within a range of, for example, 0.01 mol to 0.5 mol per 1 L of the non-aqueous solvent.

[0174] Various additives

[0175] In this embodiment, the non-aqueous electrolyte solution may further contain various additives.

[0176] The non-aqueous secondary battery of the present embodiment is stabilized by decomposing a portion of the non-aqueous electrolyte during initial charging and forming SEI on the negative electrode surface. In order to more effectively strengthen the SEI, anhydrides can be added. When the non-aqueous solvent contains acetonitrile, there is a tendency for the strength of the SEI to decrease as the temperature rises, but the strengthening of the SEI is promoted by the addition of anhydrides. Thus, by using this anhydride, the increase in internal resistance over time due to thermal history can be effectively suppressed.

[0177] Specific examples of acid anhydrides include chain anhydrides such as acetic anhydride, propionic anhydride, and benzoic anhydride; cyclic anhydrides such as malonic anhydride, succinic anhydride, glutaric anhydride, maleic anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 2,3-naphthalene dicarboxylic anhydride, or naphthalene-1,4,5,8-tetracarboxylic dianhydride; and mixed anhydrides having a structure formed by dehydration condensation of two different carboxylic acids or different acids such as a carboxylic acid and a sulfonic acid. These can be used alone or in combination of two or more.

[0178] The non-aqueous secondary battery in the present embodiment preferably strengthens SEI before the reduction decomposition of the non-aqueous solvent, and therefore preferably contains at least one of the cyclic anhydrides that play a role in the early stage of the initial charge as an acid anhydride. These cyclic anhydrides can contain only one or more. Alternatively, cyclic anhydrides other than these cyclic anhydrides can also be contained. In addition, the cyclic anhydride preferably contains at least one of succinic anhydride, maleic anhydride and phthalic anhydride.

[0179] Using a non-aqueous electrolyte containing at least one of succinic anhydride, maleic anhydride, and phthalic anhydride allows for the formation of a robust SEI at the negative electrode, more effectively suppressing resistance increases during high-temperature heating. Succinic anhydride is particularly preferred. This suppresses side reactions while more effectively forming a robust SEI at the negative electrode.

[0180] When the non-aqueous electrolyte solution in this embodiment contains an acid anhydride, its content is preferably in the range of 0.01 mass parts to 10 mass parts, more preferably 0.05 mass parts to 1 mass part, and further preferably 0.1 mass parts to 0.5 mass parts, relative to 100 mass parts of the non-aqueous electrolyte solution.

[0181] The non-aqueous electrolyte preferably contains an acid anhydride. Meanwhile, as long as the acid anhydride can function in the non-aqueous secondary battery, at least one battery component selected from the group consisting of the positive electrode, the negative electrode, and the separator may contain an acid anhydride. The acid anhydride may be incorporated into the battery component during its manufacture, or may be impregnated into the battery component through post-treatment such as coating, impregnation, or spray drying.

[0182] In addition, in this embodiment, to improve the high-temperature storage properties and safety of the non-aqueous secondary battery, the non-aqueous electrolyte may contain at least one additive selected from the group consisting of sulfonic acid esters, diphenyl disulfide, cyclohexylbenzene, biphenyl, fluorobenzene, tert-butylbenzene, phosphates (such as ethyl diethylphosphonoacetate (EDPA): (C2H5O)2(P=O)-CH2(C=O)OC2H5, tris(trifluoroethyl) phosphate (TFEP): (CF3CH2O)3P=O, triphenyl phosphate (TPP): (C6H5O)3P=O, triallyl phosphate: (CH2=CHCH2O)3P=O), nitrogen-containing cyclic compounds with no steric hindrance around unshared electron pairs (such as pyridine, 1-methyl-1H-benzotriazole, and 1-methylpyrazole), and derivatives of these compounds. Phosphate esters are particularly effective because they suppress side reactions during high-temperature storage.

[0183] The content of any additive is calculated as a mass percentage relative to the total mass of all components constituting the non-aqueous electrolyte. The content of any additive is preferably 0.01 to 10 mass%, more preferably 0.02 to 5 mass%, and even more preferably 0.05 to 3 mass%, relative to the total amount of the non-aqueous electrolyte. By adjusting the content of any additive within the above range, there is a tendency to further improve battery characteristics without compromising the basic functions of the non-aqueous secondary battery.

[0184] Ionic conductivity of non-aqueous electrolytes

[0185] In a non-aqueous secondary battery, when a separator of the preferred embodiment described below is combined with a non-aqueous electrolyte with low ionic conductivity, the migration rate of lithium ions is controlled by the ionic conductivity of the non-aqueous electrolyte, and the desired input-output characteristics may not be achieved. Therefore, the ionic conductivity of the non-aqueous electrolyte in this embodiment is preferably 10 mS / cm or higher, more preferably 15 mS / cm or higher, and even more preferably 20 mS / cm or higher.

[0186] <Method for producing non-aqueous electrolyte>

[0187] The non-aqueous electrolyte solution in the present embodiment can be produced by mixing a non-aqueous solvent, a lithium salt, and various additives added as needed by any means.

[0188] Non-aqueous Secondary Batteries

[0189] The non-aqueous secondary battery of this embodiment includes:

[0190] A positive electrode containing one or more positive electrode active materials capable of absorbing and releasing lithium ions;

[0191] a negative electrode containing at least one negative electrode active material selected from the group consisting of a material capable of occluding and releasing lithium ions and metallic lithium; and

[0192] Non-aqueous electrolyte,

[0193] The negative electrode contains at least one compound selected from the group consisting of compounds represented by the following general formula (1), the following general formula (2), and the following general formula (3).

[0194]

[0195] As the non-aqueous electrolyte, the non-aqueous electrolyte described above can be used.

[0196] The nonaqueous secondary battery of the present embodiment is typically configured by accommodating a predetermined positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte in an appropriate battery case.

[0197] Specifically, the non-aqueous secondary battery of this embodiment can be Figure 1 and 2 The non-aqueous secondary battery shown in the figure. Figure 1 This is a top view schematically showing a non-aqueous secondary battery. Figure 2 for Figure 1 AA line section view.

[0198] Figure 1 、 Figure 2 The non-aqueous secondary battery 100 shown is composed of a bag-type battery cell. The non-aqueous secondary battery 100 contains a stacked electrode body composed of a positive electrode 150 and a negative electrode 160 stacked by a separator 170, and a non-aqueous electrolyte (not shown) in the space 120 of the battery case 110. The battery case 110 is composed of, for example, an aluminum laminate film, and the outer periphery of the space formed by the two aluminum laminate films is sealed by heat-welding the upper and lower films. The stacked body in which the positive electrode 150, the separator 170 and the negative electrode 160 are stacked in sequence is impregnated with a non-aqueous electrolyte. However, the Figure 2 In order to avoid cluttering the drawing, the layers constituting the battery case 110 and the layers of the positive electrode 150 and the negative electrode 160 are not distinguished from each other.

[0199] The aluminum laminate film constituting the battery case 110 is preferably an aluminum laminate film obtained by coating both surfaces of an aluminum foil with a polyolefin-based resin.

[0200] The positive electrode 150 is connected to the positive electrode lead 130 within the non-aqueous secondary battery 100. Although not shown, the negative electrode 160 is also connected to the negative electrode lead 140 within the non-aqueous secondary battery 100. Furthermore, one end of each of the positive electrode lead 130 and the negative electrode lead 140 is extended to the outside of the battery case 110 so as to be connectable to external equipment, etc., and their ionomer portions are thermally fused to one side of the battery outer periphery 110.

[0201] about Figure 1 and 2 The illustrated non-aqueous secondary battery 100 comprises a single stacked electrode assembly for each of the positive electrode 150 and the negative electrode 160. However, the number of stacked positive and negative electrodes 150 and 160 can be increased as needed depending on the design capacity. When stacking multiple positive and negative electrodes 150 and 160, the tabs of the same electrode can be joined together by welding or other means, then connected to a single lead assembly by welding or other means, and then removed from the battery. The tabs of the same electrode can be formed by the exposed portion of the current collector or by welding a metal sheet to the exposed portion of the current collector.

[0202] The positive electrode 150 is composed of a positive electrode current collector and a positive electrode active material layer, while the negative electrode 160 is composed of a negative electrode current collector and a negative electrode active material layer.

[0203] The positive electrode active material layer contains a positive electrode active material, and the negative electrode active material layer contains a negative electrode active material.

[0204] The positive electrode 150 and the negative electrode 160 are arranged such that the positive electrode active material layer and the negative electrode active material layer face each other with the separator 170 interposed therebetween.

[0205] Hereinafter, each element constituting the non-aqueous secondary battery of this embodiment will be described in sequence.

[0206] <positive electrode>

[0207] The positive electrode contains one or more positive electrode active materials capable of occluding and releasing lithium ions.

[0208] Furthermore, the positive electrode may have a positive electrode active material layer on one or both surfaces of the positive electrode current collector.

[0209] [Positive electrode current collector]

[0210] The positive electrode current collector is made of metal foil, such as aluminum foil, nickel foil, or stainless steel foil. The surface of the positive electrode current collector may be carbon-coated or processed into a mesh shape. The thickness of the positive electrode current collector is preferably 5 to 40 μm, more preferably 7 to 35 μm, and even more preferably 9 to 30 μm.

[0211] [Positive Electrode Active Material Layer]

[0212] The positive electrode active material layer contains one or more positive electrode active materials capable of occluding and releasing lithium ions. The positive electrode active material layer may further contain a conductive assistant and / or a binder as needed.

[0213] (Positive electrode active material)

[0214] The positive electrode active material contains one or more materials capable of occluding and releasing lithium ions. When using such materials, high voltage and high energy density can be obtained.

[0215] Examples of the positive electrode active material include a positive electrode active material containing at least one transition metal element selected from the group consisting of Ni, Mn, and Co.

[0216] Preferably, it is at least one selected from the lithium metal oxides represented by the following general formula (14).

[0217] Li p Ni q Co r Mn s M t O u ·····(14)

[0218] {In the formula, M is at least one metal selected from the group consisting of Al, Sn, In, Fe, V, Cu, Mg, Ti, Zn, Mo, Zr, Sr, and Ba, and is in the range of 0 < p < 1.3, 0 < q < 1.2, 0 < r < 1.2, 0 ≤ s < 0.5, 0 ≤ t < 0.3, 0.7 ≤ q + r + s + t ≤ 1.2, 1.8 < u < 2.2, and p is a value determined by the charge and discharge state of the battery.}

[0219] In addition, examples of the positive electrode active material include

[0220] Lithium cobalt oxide represented by LiCoO2;

[0221] Lithium manganese oxides represented by LiMnO2, LiMn2O4, and Li2Mn2O4;

[0222] Lithium nickel oxide represented by LiNiO2;

[0223] With LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.8 Co 0.2 O2, LiNi 0.6 Co 0.2 Mn0.2 O2, LiNi 0.75 Co 0.15 Mn 0.15 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.85 Co 0.075 Mn 0.075 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.81 Co 0.1 Al 0.09 O2, LiNi 0.85 Co 0.1 Al 0.05 Li represented by O2 z Lithium-containing composite metal oxide represented by MO2 (M contains at least one transition metal element selected from the group consisting of Ni, Mn, and Co, and represents two or more metal elements selected from the group consisting of Ni, Mn, Co, Al, and Mg, and z represents a number greater than 0.9 and less than 1.2);

[0224] Metal oxides or metal chalcogenides having tunnel structures and layered structures represented by MnO2, FeO2, FeS2, V2O5, V6O 13 , TiO2, TiS2, MoS2, and NbSe2;

[0225] Sulfur;

[0226] Conductive polymers represented by polyaniline, polythiophene, polyacetylene, and polypyrrole, etc.

[0227] In particular, when the Ni content ratio q of the Li-containing metal oxide represented by the general formula (14) is 0.5 < q < 1.2, both the reduction of the amount of Co as a rare metal and the increase in energy density are achieved, so it is preferred.

[0228] It should be noted that the positive electrode active material may be a lithium-containing compound other than the lithium-containing metal oxide represented by the formula (14). Examples of such lithium-containing compounds include composite oxides containing lithium and transition metal elements, metal chalcogenides having lithium, phosphoric acid metal compounds containing lithium and transition metal elements, and silicic acid metal compounds containing lithium and transition metal elements. From the viewpoint of obtaining a higher voltage, as the lithium-containing compound, a phosphoric acid metal compound containing lithium and at least one transition metal element selected from the group consisting of Co, Ni, Mn, Fe, Cu, Zn, Cr, V, and Ti is particularly preferred.

[0229] More specifically, examples of the lithium-containing compound include compounds represented by the following formula (16a), the following formula (16b), and the following formula (16c).

[0230] Li v M I D2(16a)

[0231] {wherein, D represents a chalcogen element, M I represents one or more transition metal elements including at least one transition metal element, the value of v is determined by the charge and discharge state of the battery and represents a number from 0.05 to 1.10, and u represents a number from 0 to 2.

[0232] Li w M II PO4(16b)

[0233] {wherein, D represents a chalcogen element, M II represents one or more transition metal elements including at least one transition metal element, the value of w is determined by the charge and discharge state of the battery and represents a number from 0.05 to 1.10, and u represents a number from 0 to 2.

[0234] Li t M III u SiO4(16c)

[0235] {wherein, D represents a chalcogen element, M III represents one or more transition metal elements including at least one transition metal element, the value of t is determined by the charge and discharge state of the battery and represents a number from 0.05 to 1.10, and u represents a number from 0 to 2.

[0236] The lithium-containing compound represented by the above formula (16a) has a layered structure, and the compounds represented by the above formulas (16b) and (16c) have an olivine structure. These lithium-containing compounds may be substances in which a portion of a transition metal element is replaced with Al, Mg, or other transition metal elements for the purpose of stabilizing the structure, substances containing these metal elements at the grain boundaries, substances in which a portion of oxygen atoms is replaced with fluorine atoms, or substances in which at least a portion of the surface of the positive electrode active material is covered with other positive electrode active materials.

[0237] The positive electrode active material may be used alone or in combination. From the perspective of being able to reversibly and stably store and release lithium ions and achieve high energy density, the positive electrode active material layer preferably contains at least one transition metal element selected from Ni, Mn, and Co.

[0238] When a lithium-containing compound and other positive electrode active materials are used in combination as a positive electrode active material, the ratio of the lithium-containing compound to the total positive electrode active material is preferably 80% by mass or more, more preferably 85% by mass or more.

[0239] (Conductive additive)

[0240] Examples of conductive additives include carbon black represented by graphite, acetylene black, and Ketjen black, and carbon fibers. The content of the conductive additive is preferably 10 parts by mass or less, more preferably 1 to 5 parts by mass, based on 100 parts by mass of the positive electrode active material.

[0241] (Binder)

[0242] Examples of the binder include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid, styrene-butadiene rubber, and fluororubber. The binder content is preferably 6 parts by mass or less, more preferably 0.5 to 4 parts by mass, based on 100 parts by mass of the positive electrode active material.

[0243] [Formation of Positive Electrode Active Material Layer]

[0244] The positive electrode active material layer is formed as follows: a positive electrode mixture formed by mixing a positive electrode active material and a conductive auxiliary agent and a binder as needed is dispersed in a solvent, and the slurry containing the positive electrode mixture thus obtained is applied to the positive electrode collector and dried (to remove the solvent), and pressed as needed to form. As such a solvent, a known solvent can be used. For example, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, water, etc. can be listed.

[0245] <negative electrode>

[0246] The negative electrode in the nonaqueous secondary battery of this embodiment has a negative electrode active material layer on one or both surfaces of a negative electrode current collector.

[0247] The negative electrode contains at least one negative electrode active material selected from the group consisting of a material capable of occluding and releasing lithium ions and metallic lithium.

[0248] Here, the negative electrode contains at least one compound selected from the group consisting of compounds represented by the following general formula (1), the following general formula (2), and the following general formula (3).

[0249]

[0250] By using at least one selected from the group consisting of compounds represented by general formula (1) to (3), the physical strength of the negative electrode against expansion and contraction is further enhanced, thereby easily suppressing the degradation of electrode characteristics caused by charge and discharge cycles. In particular, since the compound represented by general formula (1) has lithium at both ends and the molecular chain is long, it is speculated from the structure that the negative electrode has strong physical strength against expansion and contraction and low resistance. In addition, the molecular chain of the compound represented by general formula (2) or (3) is short, and it is speculated from the structure that a dense protective film with excellent durability is formed. On the other hand, if the content is too much, it may become the main cause of the increase in resistance, so it needs to be suppressed within a fixed range. Therefore, by using at least one selected from the group consisting of compounds represented by general formula (1) to (3), it is easy to ensure the balance between the physical strength of the negative electrode against expansion and contraction and the solubility.

[0251] The content of at least one compound selected from the group consisting of compounds represented by general formulae (1) to (3) is calculated by dividing the quantitative value obtained by analyzing the components of the negative electrode protective film by the mass of the negative electrode active material. The sum of the contents of the compounds represented by general formulae (2) and (3) is preferably 0.01 to 2.5 mg relative to 1 g of the negative electrode active material. In addition, the content of at least one compound selected from the group consisting of compounds represented by general formulae (1) to (3) is preferably 0.01 to 100 mg, more preferably 0.05 to 50 mg, and further preferably 0.1 to 10 mg relative to 1 g of the negative electrode active material. By being within this range, the basic function as a non-aqueous secondary battery is not impaired, and the increase in film resistance caused by the charge and discharge cycle is easily suppressed. It should be noted that it is preferred to satisfy the above content within the range up to 100 cycles of repeated charge and discharge.

[0252] In this case, the negative electrode may contain PF6 anions, and may also contain N(SO2F)2 anions and / or N(SO2CF3)2 anions. That is, the non-aqueous electrolyte may contain at least one anion selected from the group consisting of PF6 anions, N(SO2CF3)2, or N(SO2F)2 anions. The anions promote the formation of a protective film while forming a non-conductive film on the surface of the surface foil serving as the positive electrode current collector, and are therefore preferred from the perspective of suppressing an increase in internal resistance.

[0253] The content of at least one selected from the group consisting of compounds represented by general formulae (1) to (3) in the negative electrode was calculated by dividing the quantitative value obtained by analyzing the negative electrode protective film components by the mass of the negative electrode active material.

[0254] [Negative Electrode Active Material Layer]

[0255] The negative electrode active material layer contains a negative electrode active material and may further contain a conductive additive and / or a binder as needed.

[0256] (Negative electrode active material)

[0257] The negative electrode active material is at least one selected from the group consisting of a material capable of occluding and releasing lithium ions and metallic lithium.

[0258] Examples of such negative electrode active materials include carbon materials such as amorphous carbon (hard carbon), artificial graphite, natural graphite, graphite, pyrolytic carbon, coke, glassy carbon, calcined organic polymer compounds, mesocarbon microbeads, carbon fibers, activated carbon, graphite, carbon colloids, and carbon black, as well as metallic lithium, metal oxides, metal nitrides, lithium alloys, tin alloys, Si materials, intermetallic compounds, organic compounds, inorganic compounds, metal complexes, and organic polymer compounds. The negative electrode active material may be used alone or in combination of two or more. Examples of the Si material include silicon, Si alloys, and Si oxides.

[0259] From the viewpoint of increasing the battery voltage, the negative electrode active material layer preferably contains a + Materials that absorb lithium ions at low potentials serve as negative electrode active materials.

[0260] The non-aqueous electrolyte of this embodiment has the advantage of suppressing various degradation phenomena associated with volume changes of the negative electrode during repeated charge-discharge cycles, even when a Si material is used as the negative electrode active material. Therefore, in the non-aqueous secondary battery of this embodiment, using a Si material, such as a silicon alloy, as the negative electrode active material is a preferred method, as it provides the high capacity derived from the Si material and excellent charge-discharge cycle characteristics.

[0261] In this embodiment, the negative electrode active material may contain Si material, particularly SiO x (0.5≤x≤1.5).

[0262] In addition, in this embodiment, it is preferred to contain at least one element capable of forming an alloy with lithium. Examples of such elements include silicon. The Si material may be in any of a crystalline, low-crystalline, and amorphous form. In addition, when using a Si material as the negative electrode active material, it is preferred to cover the active material surface with a conductive material because this improves the conductivity between the active material particles.

[0263] The working potential of silicon is about 0.5V (vsLi / Li + ), about 0.05V (vsLi / Li) relative to the working potential of graphite +) is slightly higher. Therefore, the use of Si materials reduces the risk of lithium electrodeposition. The acetonitrile used in the non-aqueous solvent of this embodiment may undergo a reduction reaction with lithium metal, causing gas generation. Therefore, it is preferable to use a negative electrode active material that is not susceptible to lithium electrodeposition in combination with a non-aqueous electrolyte containing acetonitrile.

[0264] On the other hand, the negative electrode active material with too high an operating potential will reduce the energy density of the battery. Therefore, from the viewpoint of improving the energy density, the negative electrode active material is preferably at a voltage of 0.4 V vs. Li / Li. + Work at low potential.

[0265] The content of the Si material, relative to the total amount of the negative electrode active material layer, is preferably within a range of 0.1% to 100% by mass, more preferably within a range of 1% to 80% by mass, and even more preferably within a range of 3% to 60% by mass. By adjusting the content of the Si material within the above range, a balance between high capacity and charge-discharge cycle performance of the non-aqueous secondary battery can be ensured.

[0266] (Conductive additive)

[0267] Examples of the conductive additive include carbon black represented by graphite, acetylene black, and Ketjen black, and carbon fibers. The content of the conductive additive is preferably 20 parts by mass or less, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the negative electrode active material.

[0268] (Binder)

[0269] Examples of the binder include carboxymethylcellulose, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid, and fluororubber. Diene rubbers, such as styrene-butadiene rubber, are also included. The binder content is preferably 10 parts by mass or less, and more preferably 0.5 to 6 parts by mass, relative to 100 parts by mass of the negative electrode active material.

[0270] [Formation of Negative Electrode Active Material Layer]

[0271] The negative electrode active material layer is formed as follows: a negative electrode mixture obtained by mixing a negative electrode active material and a conductive aid and / or a binder as needed is dispersed in a solvent, a slurry containing the negative electrode mixture thus obtained is applied to a negative electrode current collector and dried (to remove the solvent), and pressed as needed to form. As such a solvent, a known solvent can be used. For example, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, water, etc. can be listed.

[0272] [Decomposition products of acid anhydride]

[0273] Here, the negative electrode active material preferably contains a decomposition product of a cyclic acid anhydride. Specific examples of the cyclic acid anhydride include those listed in the section "Various Additives".

[0274] Specifically, the decomposition product of the cyclic acid anhydride that may be contained in the negative electrode active material is preferably at least one selected from the group consisting of malonic anhydride, succinic anhydride, glutaric anhydride, maleic anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 2,3-naphthalene dicarboxylic anhydride, and naphthalene-1,4,5,8-tetracarboxylic dianhydride.

[0275] In the negative electrode, acid anhydride is used to more effectively strengthen the SEI on the negative electrode surface.

[0276] The amount of decomposition products of the acid anhydride is calculated based on the peak area value measured by LC-MS relative to the unit gram mass of the negative electrode active material. The amount of decomposition products of the acid anhydride (the content of at least one compound selected from the group consisting of compounds represented by the following general formulas (8) to (13)) is preferably an amount with a peak area value in the range of 0.1 to 300, more preferably an amount in the range of 1 to 200, and further preferably an amount in the range of 20 to 150 relative to 1 μg of the negative electrode active material. By having the peak area value within this range, the balance between the suppression of the increase in film resistance and the solubility can be ensured. It should be noted that the above content is preferably satisfied within the range up to 100 cycles of repeated charge and discharge.

[0277] The decomposition product of the acid anhydride preferably contains at least one compound selected from the group consisting of compounds represented by the following general formula (8), the following general formula (9), the following general formula (10), the following general formula (11), the following general formula (12) and the following general formula (13).

[0278]

[0279] {In general formula (8), R 6 and R 7 represents an alkoxy group, an OH group or an OLi group which may be substituted by a halogen atom, and f is an integer of 1 to 3,}

[0280]

[0281] {In general formula (9), R 8 and R 9 represents an alkoxy group, OH group or OLi group which may be substituted by a halogen atom,}

[0282]

[0283] {In the general formula (10), R 10 and R 11represents an alkoxy group, OH group or OLi group which may be substituted by a halogen atom,}

[0284]

[0285] {In the general formula (11), R 12 and R 13 represents an alkoxy group, OH group or OLi group which may be substituted by a halogen atom,}

[0286]

[0287] {In general formula (12), R 14 and R 15 represents an alkoxy group, OH group or OLi group which may be substituted by a halogen atom,}

[0288]

[0289] {In general formula (13), R 16 ~R 19 represents an alkoxy group, an OH group or an OLi group which may be substituted by a halogen atom.}

[0290] It should be noted that the "halogen atom" in the description of general formulae (8) to (13) may include a F atom.

[0291] These compounds contribute to the strengthening of the SEI on the negative electrode surface. They exhibit particularly excellent effects when acetonitrile is used as a non-aqueous solvent. Therefore, it is preferred that the anhydride is not unnecessarily consumed on the positive electrode side.

[0292] 〈Separator〉

[0293] From the viewpoints of giving safety such as preventing the short circuit of the positive and negative electrodes, closing, etc., the non-aqueous secondary battery of the present embodiment preferably has a separator between the positive and negative electrodes. As a separator, the same separator as the separator possessed in the known non-aqueous secondary battery can be used, preferably an insulating film with large ion permeability and excellent mechanical strength. As the raw materials constituting the separator, for example, woven fabrics, non-woven fabrics, synthetic resin microporous membranes, etc. can be listed, among which, synthetic resin microporous membranes are preferably used. In particular, polyolefin-based microporous membranes such as microporous membranes containing polyethylene or polypropylene as main components or microporous membranes containing these polyolefins can be suitably used. As non-woven fabrics, porous membranes such as heat-resistant resins such as glass, ceramic, polyolefin, polyester, polyamide, liquid crystal polyester, and aromatic polyamide can be listed.

[0294] The separator may be a structure formed by laminating a single or multiple layers of a single microporous membrane, or a structure formed by laminating two or more microporous membranes. The separator may also be a structure formed by laminating a single or multiple layers of a mixed resin material obtained by melt-kneading two or more resin materials.

[0295] To impart specific functions to the separator, inorganic particles may be present on the surface or within the separator. Furthermore, the separator may be further coated or laminated with other organic layers. Furthermore, the separator may contain a cross-linked structure. These methods may be combined as needed to enhance the safety of non-aqueous secondary batteries.

[0296] To impart specific functions to the separator, inorganic particles may be present on the surface or within the separator. Furthermore, the separator may be further coated or laminated with other organic layers. Furthermore, the separator may contain a cross-linked structure. These methods may be combined as needed to enhance the safety of non-aqueous secondary batteries.

[0297] The separator 170 may be a structure formed by laminating a single microporous membrane in a single layer or multiple layers, or may be a structure formed by laminating two or more microporous membranes in a single layer. Furthermore, the separator 170 may be a structure formed by laminating a mixed resin material obtained by melt-kneading two or more resin materials in a single layer or multiple layers.

[0298] From the perspective of membrane strength, the thickness of the separator is preferably 1 μm or more, and from the perspective of permeability, it is preferably 500 μm or less. From the perspective of relatively high heat release, for high output applications, and from the perspective of windability achieved by a large battery winding machine, it is preferably 3 μm or more and 40 μm or less, more preferably 10 μm or more and 25 μm or less. It should be noted that when taking into account both short-circuit resistance and output performance, it is further preferred that it is 15 μm or more and 25 μm or less, and when taking into account both high energy density and output performance, it is further preferred that it is 10 μm or more and less than 15 μm.

[0299] From the perspective of catching up with the rapid migration of lithium ions at high output, the porosity is preferably 30% to 90%, more preferably 35% to 80%, and even more preferably 40% to 70%. It should be noted that when ensuring safety while prioritizing improved output performance, a porosity of 50% to 70% is particularly preferred. When balancing short-circuit resistance and output performance, a porosity of 40% to less than 50% is particularly preferred.

[0300] From the perspective of balance with film thickness and porosity, the air permeability is preferably 1 second / 100 cm 3 Above 400 seconds / 100cm 3 Less than, more preferably 100 seconds / 100cm3 Above and 350 / 100cm 3 It should be noted that, when balancing short-circuit resistance and output performance, 150 seconds / 100 cm is more preferred. 3 Above 350 seconds / 100cm 3 Below, when ensuring safety while giving priority to improving output performance, 100 / 100cm is particularly preferred. 3 More than 10 seconds and less than 150 seconds / 100cm 3 .

[0301] On the other hand, when combining a non-aqueous electrolyte with low ionic conductivity with a separator within the above range, the migration rate of lithium ions is controlled by the ionic conductivity of the non-aqueous electrolyte rather than the structure of the separator, and there is a tendency for the expected input-output characteristics to not be achieved. Therefore, the ionic conductivity of the non-aqueous electrolyte is preferably 10 mS / cm or higher, more preferably 15 mS / cm or higher, and even more preferably 20 mS / cm or higher.

[0302] However, the thickness, air permeability and porosity of the separator, and the ion conductivity of the non-aqueous electrolyte are merely examples.

[0303] To impart specific functions to the separator, inorganic particles may be present on the surface or within the separator. Furthermore, the separator may be further coated or laminated with other organic layers. Furthermore, the separator may contain a cross-linked structure. These methods may be combined as needed to enhance the safety of non-aqueous secondary batteries.

[0304] Battery case

[0305] The battery case of the non-aqueous secondary battery of this embodiment can adopt a known structure. For example, a battery can or a laminated film outer shell can be used as the battery case.

[0306] As the battery can, for example, a metal can made of steel, stainless steel, aluminum, or clad steel can be used.

[0307] Regarding the laminated film housing, two sheets can be overlapped with the hot melt resin side facing inward or bent in a manner such that the hot melt resin side faces inward, and used as the housing in a state where the ends are sealed by heat sealing. In the case of using a laminated film housing, a positive electrode lead (or a positive terminal and a lead tab connected to the positive terminal) can be connected to the positive electrode collector, and a negative electrode lead (or a negative terminal and a lead tab connected to the negative terminal) can be connected to the negative electrode collector. At this time, the laminated film housing can be sealed in a state where the ends of the positive electrode lead and the negative electrode lead (or the lead tabs connected to the positive terminal and the negative terminal, respectively) are led out to the outside of the housing.

[0308] As the laminated film housing, for example, a laminated film having a three-layer structure of hot melt resin / metal film / resin can be used.

[0309] The aluminum laminate film constituting the battery case 110 is preferably formed by coating both surfaces of an aluminum foil with a polyolefin-based resin.

[0310] <Shape of non-aqueous secondary batteries>

[0311] The nonaqueous secondary battery of this embodiment can be applied to shapes such as a square, a square cylinder, a cylinder, an oval, a button, a coin, a flat, and a laminated type.

[0312] The non-aqueous secondary battery of this embodiment is particularly preferably applicable to a prismatic, cylindrical, and laminated type.

[0313] <Method for manufacturing non-aqueous secondary battery>

[0314] The nonaqueous secondary battery of this embodiment can be produced by a known method using the above-mentioned nonaqueous electrolyte, positive electrode, negative electrode, separator, and battery case.

[0315] First, a stacked body consisting of a positive electrode, a negative electrode, and a separator is formed.

[0316] For example, it can be as follows:

[0317] A method of winding a stacked body of a wound structure by winding long positive and negative electrodes with a long separator interposed between them;

[0318] The positive electrode and the negative electrode are cut into multiple sheets with a fixed area and shape, and the obtained positive and negative electrode sheets are alternately stacked with separator sheets to form a laminated structure;

[0319] A method of forming a laminated body by folding a long separator in a zigzag shape multiple times, and alternately inserting positive electrode sheets and negative electrode sheets into the gaps between the zigzag-shaped separators to form a laminated body; etc.

[0320] Next, the stacked body is housed in a battery case, and the nonaqueous electrolyte of this embodiment is injected into the battery case to immerse the stacked body in the nonaqueous electrolyte and seal the battery case, thereby manufacturing the nonaqueous secondary battery of this embodiment.

[0321] As another method, the non-aqueous electrolyte of the present embodiment may be impregnated into a substrate formed of a polymer material to pre-prepare a gel-state electrolyte membrane, and a laminated structure formed of a sheet-like positive electrode, a negative electrode, the obtained electrolyte membrane, and a separator may be used to form the laminated structure, which may then be housed in a battery case to manufacture a non-aqueous secondary battery.

[0322] It should be noted that when the electrode configuration is designed in such a way that there is a portion where the peripheral end of the negative electrode active material layer overlaps with the peripheral end of the positive electrode active material layer, or in such a way that there is a portion with a narrow width in the non-opposing portion of the negative electrode active material layer, the position of the electrode may be offset during battery assembly. In this case, the charge and discharge cycle characteristics of the non-aqueous secondary battery may be reduced. In order to prevent this situation, it is preferred to fix the position of the electrode in advance using tapes such as polyimide tape, polyphenylene sulfide tape, PP tape, adhesives, etc.

[0323] The non-aqueous secondary battery of this embodiment can function as a battery by the first charge, and is stabilized by the decomposition of a portion of the non-aqueous electrolyte during the first charge. The first charge is preferably performed at 0.001 to 0.3C, more preferably at 0.002 to 0.25C, and even more preferably at 0.003 to 0.2C. Performing the first charge via constant voltage charging during the process also produces preferred results. The constant current for discharging the designed capacity in 1 hour is 1C. By setting the voltage range in which the lithium salt participates in the electrochemical reaction to a longer range, a stable and firm SEI is formed on the electrode surface, which suppresses the increase in internal resistance, and the reaction product is not only firmly fixed to the negative electrode 160, but also has a good effect on components other than the negative electrode 160, such as the positive electrode 150 and the separator 170, in some form. Therefore, it is very effective to perform the first charge taking into account the electrochemical reaction of the lithium salt dissolved in the non-aqueous electrolyte.

[0324] The non-aqueous secondary battery of this embodiment can also be used in the form of a battery pack consisting of multiple non-aqueous secondary batteries connected in series or in parallel. From the perspective of managing the charge and discharge state of the battery pack, the operating voltage range of each non-aqueous secondary battery is preferably 2-5V, more preferably 2.5-5V, and particularly preferably 2.75V-5V.

[0325] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments and can be modified in various ways without departing from the spirit and scope of the present invention.

[0326] In particular, this embodiment (hereinafter referred to as "Embodiment 1") can be combined with at least one of the other embodiments 1 to 5 described later. That is, in the non-aqueous secondary battery of Embodiment 1, at least one of the specific additives described in the other embodiments 1 to 5 described later can be added to the non-aqueous electrolyte.

[0327] As a combination, the following can be listed:

[0328] Implementation 1 and other implementations 1;

[0329] Implementation 1 and other implementations 1 and 2;

[0330] Embodiment 1 and other embodiments 1, 2, and 3;

[0331] Embodiment 1 and other embodiments 1, 2, and 4;

[0332] Embodiment 1 and other embodiments 1, 2, and 5;

[0333] Embodiment 1 and other embodiments 1, 2, 3 and 4;

[0334] Embodiment 1 and other embodiments 1, 2, 3 and 5;

[0335] Embodiment 1 and other embodiments 1, 2, 3, 4 and 5; Embodiment 1 and other embodiments 1 and 3;

[0336] Embodiment 1 and other embodiments 1, 3 and 4;

[0337] Embodiment 1 and other embodiments 1, 3 and 5;

[0338] Embodiment 1 and other embodiments 1, 3, 4 and 5;

[0339] Implementation 1 and other implementations 1 and 4;

[0340] Embodiment 1 and other embodiments 1, 4 and 5;

[0341] Implementation 1 and other implementations 1 and 5;

[0342] Implementation 1 and other implementation 2;

[0343] Implementation method 1 and other implementation methods 2 and 3;

[0344] Implementation 1 and other implementations 2 and 4;

[0345] Implementation method 1 and other implementation methods 2 and 5;

[0346] Embodiment 1 and other embodiments 2, 3 and 4;

[0347] Implementation 1 and other implementations 2, 3, and 5;

[0348] Embodiment 1 and other embodiments 2, 3, 4 and 5;

[0349] Embodiment 1 and other embodiments 2, 4 and 5;

[0350] Implementation 1 and other implementation 3;

[0351] Implementation method 1 and other implementation methods 3 and 4;

[0352] Implementation method 1 and other implementation methods 3 and 5;

[0353] Embodiment 1 and other embodiments 3, 4 and 5;

[0354] Implementation 1 and other implementation 4;

[0355] Implementation method 1 and other implementation methods 4 and 5;

[0356] Implementation method 1 and other implementation methods 5.

[0357] By achieving this combination, it is possible to obtain a synergistic effect from the perspective of suppressing the active points of the positive electrode active material that cause oxidative degradation of the non-aqueous electrolyte and from the perspective of suppressing various degradation phenomena associated with the volume change of the negative electrode during repeated charge and discharge cycles when Si material is applied to the negative electrode active material.

[0358] <Other embodiment 1>

[0359] The present embodiment relates to a non-aqueous secondary battery in which a non-aqueous electrolyte solution contains at least one nitric acid compound selected from the group consisting of nitrates and nitrate esters.

[0360] Background technology and problems involved in this embodiment

[0361] In recent years, with the expansion of the large-scale power storage industry centered on electric vehicles, there has been a desire for further higher energy density of non-aqueous secondary batteries, and research and development has flourished.

[0362] Non-Patent Document 1 reports that, in a layered rock salt type positive electrode active material, the higher the Ni content, the higher the energy density.

[0363] However, for non-aqueous secondary batteries, while energy density improves, long-term durability may also deteriorate. For example, Non-Patent Document 2 discusses a unique degradation factor, stating that a higher Ni ratio leads to more rapid degradation at lower voltages. Non-Patent Document 3 reports a mechanism in which the decomposition of high-dielectric-constant solvents triggers the decomposition of lithium salts.

[0364] However, research is underway to use Si materials as negative electrode active materials instead of conventional carbon materials. This is due to the fact that the theoretical capacity of Si materials is greater than that of carbon materials.

[0365] For example, when graphite is used as the negative electrode active material, the maximum amount of lithium absorption and release per 1 mol of carbon is 1 / 6 mol, and the theoretical capacity obtained by LiC6 as the largest lithium-introducing compound is 372 mAh / g. In contrast, when Si material is used, the maximum amount of lithium absorption and release per 1 mol of Si is 3.75 mol, and the theoretical capacity obtained by LiC6 is 372 mAh / g. 3.75 The theoretical capacity of Si reaches 3600 mAh / g.

[0366] [Non-patent document 1] ACS Energy Lett., 2, 196-223 (2017).

[0367] [Non-patent document 2] J. Power Sources, 233, 121-130 (2013).

[0368] [Non-patent document 3] J. Phys. Chem. Lett., 8, 4820-4825 (2017).

[0369] However, these non-aqueous secondary batteries aiming for higher energy density may have inferior long-term durability compared to conventional non-aqueous secondary batteries, and require both the electrolyte and the electrodes to have durability under more severe environments.

[0370] Layered rock salt-type positive electrode active materials inherently contain active sites that can cause oxidative degradation of the electrolyte. These active sites can unexpectedly consume the compounds added to protect the negative electrode on the positive electrode side. Furthermore, the decomposition products of these additives, introduced and accumulated on the positive electrode side, can not only increase the internal resistance of non-aqueous secondary batteries but also accelerate the degradation of lithium salts. Furthermore, the unexpected consumption of these additives can lead to inadequate protection of the negative electrode surface.

[0371] These phenomena, which were confirmed by the results of disassembly analysis, are not described in Non-Patent Documents 1 to 3.

[0372] On the other hand, when Si material is used as the negative electrode active material, the volume change of the Si material when absorbing and releasing Li ions may become a problem.

[0373] For example, the maximum volume change of graphite when absorbing and releasing Li ions is approximately 1.2 times, whereas the use of Si can result in a larger volume change of approximately 4 times. This can make the battery mechanically fragile, and in particular, the cycle life of the negative electrode may be insufficient, which can be a significant obstacle to practical use.

[0374] Effects of this embodiment

[0375] According to this embodiment, first, a non-aqueous electrolyte and a non-aqueous secondary battery are provided that suppress the active sites of the positive electrode active material that cause oxidative degradation of the non-aqueous electrolyte, exhibit excellent load characteristics, and can suppress various degradation phenomena during high-temperature storage or repeated charge and discharge cycles.

[0376] According to the present embodiment, a non-aqueous electrolyte and a non-aqueous secondary battery are provided that can suppress various degradation phenomena associated with volume changes of the negative electrode during repeated charge and discharge cycles when Si material is used as the negative electrode active material.

[0377] <First Specific Additive>

[0378] In the present embodiment, the nitric acid compound contained in the non-aqueous electrolyte is preferably one or more selected from the group consisting of, for example, nitrates represented by the following formula (N1) and nitrate esters represented by the following formula (N2).

[0379]

[0380] {In formula (N1), X n+ is a metal cation or an organic cation; n is the valence of X.}

[0381]

[0382] {In formula (N2), R is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkenyloxy group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyloxy group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 5 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 20 carbon atoms, a hydride ion, a halogen atom, a hydroxyl group, a thiol group, an imino group , carboxyl group, alkylcarbonyloxy group, alkenylcarbonyloxy group, alkynylcarbonyloxy group, arylcarbonyloxy group, alkylthio group, alkenylthio group, alkynylthio group, arylthio group, cyano group, N-substituted amino group, alkylcarbonylamino group, N-substituted alkylcarbonylamino group, alkenylcarbonylamino group, N-substituted alkenylcarbonylamino group, alkynylcarbonylamino group, N-substituted alkynylcarbonylamino group, arylcarbonylamino group, N-substituted arylcarbonylamino group, a boron atom-containing group, an aluminum atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, or a sulfur atom-containing group.

[0383] Such a nitric acid compound may be hereinafter referred to as a "first specific additive" in this specification.

[0384] In the nitrate of the above formula (N1), X n+The metal cation is preferably a cation of a metal selected from alkali metals, alkaline earth metals and transition metals. Specifically, examples of alkali metal cations include lithium ions and cesium ions; examples of alkaline earth metal cations include magnesium ions; and examples of transition metal cations include aluminum ions.

[0385] As X n+ The organic cations include, for example, tetraalkylammonium ions, preferably tetramethylammonium ions. One or more of the methyl groups of the tetramethylammonium ion may be replaced by organic groups other than methyl groups. The substituents in this case may be, for example, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms, substituted or unsubstituted alkenyl groups having 2 to 20 carbon atoms, substituted or unsubstituted alkenyloxy groups having 2 to 20 carbon atoms, substituted or unsubstituted alkynyl groups having 2 to 20 carbon atoms, substituted or unsubstituted alkynyloxy groups having 2 to 20 carbon atoms, substituted or unsubstituted aryl groups having 5 to 20 carbon atoms, substituted or unsubstituted aryloxy groups having 5 to 20 carbon atoms, hydride ions, halogen atoms, hydroxyl groups, sulfhydryl groups, imino groups. , carboxyl, alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, arylcarbonyloxy, alkylthio, alkenylthio, alkynylthio, arylthio, cyano, N-substituted amino, alkylcarbonylamino, N-substituted alkylcarbonylamino, alkenylcarbonylamino, N-substituted alkenylcarbonylamino, alkynylcarbonylamino, N-substituted alkynylcarbonylamino, arylcarbonylamino, N-substituted arylcarbonylamino, a group containing a boron atom, a group containing an aluminum atom, a group containing a silicon atom, a group containing a phosphorus atom, a group containing a sulfur atom, etc.

[0386] The nitrate ester of the above formula (N2) is preferably isobutyl nitrate represented by the following formula (N3).

[0387]

[0388] Nitrates in which the isobutyl group of isobutyl nitrate is replaced with other lower alkyl groups (such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, or tert-butyl) are also included in the preferred embodiments of the present invention.

[0389] The nitric acid compound contained in the non-aqueous electrolyte is more preferably at least one selected from the group consisting of lithium nitrate, sodium nitrate, cesium nitrate, aluminum nitrate, magnesium nitrate, isobutyl nitrate, tetramethylammonium nitrate, and tetraethylammonium nitrate.

[0390] (Amount of the first specific additive)

[0391] The amount of the first specific additive (nitric acid compound) contained in the non-aqueous electrolyte is arbitrary, for example, it can be 0.01 mass parts or more and 10.0 mass parts or less relative to 100 mass parts of non-aqueous electrolyte. If the amount of the nitric acid compound is 0.01 mass parts or more relative to 100 mass parts of non-aqueous electrolyte, the mechanical strength of the SEI generated on the negative electrode is sufficiently high, and a non-aqueous secondary battery with excellent cycle characteristics and long-term stable operation can be obtained. On the other hand, if the amount of the nitric acid compound is 10.0 mass parts or less relative to 100 mass parts of non-aqueous electrolyte, the lithium ion conduction of the electrolyte will not be excessively hindered, and a non-aqueous secondary battery with excellent output characteristics can be obtained. The amount of the nitric acid compound contained in the non-aqueous electrolyte can be 0.05 mass parts or more and 5.0 mass parts or less, 0.1 mass parts or more and 4.0 mass parts or less, or 0.2 mass parts or more and 3.0 mass parts or less relative to 100 mass parts of non-aqueous electrolyte.

[0392] <Method for producing non-aqueous electrolyte>

[0393] The non-aqueous electrolyte solution can be produced by mixing a non-aqueous solvent, a lithium salt, a first specific additive (nitric acid compound), and other additives as needed by any means.

[0394] <Other embodiment 2>

[0395] This embodiment relates to a non-aqueous secondary battery in which a non-aqueous electrolyte contains at least one additive selected from the group consisting of a polymer compound containing a repeating unit represented by any of the following general formula (P1), the following general formula (P2), the following general formula (P3) and the following general formula (P4) and a carboxylate compound.

[0396]

[0397] {In the general formula (P1), R1 is a hydrogen atom or an alkyl group,}

[0398]

[0399] {In general formula (P2), n1 to n3 are the number of repeating units, each independently being an integer from 0 to 4,}

[0400]

[0401] {In the general formula (P3), R2 is an alkyl group having 1 to 20 carbon atoms or a fluoroalkyl group having 1 to 20 carbon atoms,}

[0402]

[0403] {In the general formula (P4), R3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.}

[0404] Background technology and problems involved in this embodiment

[0405] In recent years, with the expansion of the large-scale power storage industry centered on electric vehicles, there has been a desire for further higher energy density of non-aqueous secondary batteries, and research and development has flourished.

[0406] Non-Patent Document 1 reports that, in a layered rock salt type positive electrode active material, the higher the Ni content, the higher the energy density.

[0407] However, for non-aqueous secondary batteries, while energy density improves, long-term durability may also deteriorate. For example, Non-Patent Document 2 discusses a unique degradation factor, stating that a higher Ni ratio leads to more rapid degradation at lower voltages. Non-Patent Document 3 reports a mechanism in which the decomposition of high-dielectric-constant solvents triggers the decomposition of lithium salts.

[0408] However, research is underway to use Si materials as negative electrode active materials instead of conventional carbon materials. This is due to the fact that the theoretical capacity of Si materials is greater than that of carbon materials.

[0409] For example, when graphite is used as the negative electrode active material, the maximum amount of lithium absorption and release per 1 mol of carbon is 1 / 6 mol, and the theoretical capacity obtained by LiC6 as the largest lithium-introducing compound is 372 mAh / g. In contrast, when Si material is used, the maximum amount of lithium absorption and release per 1 mol of Si is 3.75 mol, and the theoretical capacity obtained by LiC6 is 372 mAh / g. 3.75 The theoretical capacity of Si reaches 3600 mAh / g.

[0410] [Non-patent document 1] ACS Energy Lett., 2, 196-223 (2017).

[0411] [Non-patent document 2] J. Power Sources, 233, 121-130 (2013).

[0412] [Non-patent document 3] J. Phys. Chem. Lett., 8, 4820-4825 (2017).

[0413] However, these non-aqueous secondary batteries aiming for higher energy density may have inferior long-term durability compared to conventional non-aqueous secondary batteries, and require both the electrolyte and the electrodes to have durability under more severe environments.

[0414] Layered rock salt-type positive electrode active materials inherently contain active sites that can cause oxidative degradation of the electrolyte. These active sites can unexpectedly consume the compounds added to protect the negative electrode on the positive electrode side. Furthermore, the decomposition products of these additives, introduced and accumulated on the positive electrode side, can not only increase the internal resistance of non-aqueous secondary batteries but also accelerate the degradation of lithium salts. Furthermore, the unexpected consumption of these additives can lead to inadequate protection of the negative electrode surface.

[0415] These phenomena, which were confirmed by the results of disassembly analysis, are not described in Non-Patent Documents 1 to 3.

[0416] Furthermore, non-aqueous secondary batteries may have improved capacity when used in a high-temperature environment, but repeated charge and discharge cycles may cause a rapid decrease in capacity, shortening the battery life.

[0417] Furthermore, since a high operating voltage of a secondary battery is advantageous, non-aqueous secondary batteries capable of high-voltage operation have been explored. However, if a secondary battery using a conventional non-aqueous solvent is subjected to high-voltage operation, the battery performance may deteriorate rapidly due to repeated charge and discharge cycles.

[0418] On the other hand, when Si material is used as the negative electrode active material, the volume change of the Si material when absorbing and releasing Li ions may become a problem.

[0419] For example, the maximum volume change of graphite when absorbing and releasing Li ions is approximately 1.2 times, whereas using Si can result in a large volume change of approximately 4 times. This can make the battery mechanically fragile, and in particular, the cycle life of the negative electrode may be insufficient, which can be a significant obstacle to practical use.

[0420] Effects of this embodiment

[0421] According to this embodiment, the first aspect provides a non-aqueous electrolyte and a non-aqueous secondary battery that suppresses the active points of the positive electrode active material that causes oxidative degradation of the non-aqueous electrolyte, exhibits excellent load characteristics, can suppress various degradation phenomena during repeated charge and discharge cycles, and has excellent high-temperature characteristics and is capable of high-voltage operation.

[0422] According to the present embodiment, a non-aqueous electrolyte and a non-aqueous secondary battery are provided that can suppress various degradation phenomena associated with volume changes of the negative electrode during repeated charge and discharge cycles when Si material is used as the negative electrode active material.

[0423] <Second Specific Additive>

[0424] The non-aqueous electrolyte solution of the present embodiment contains, as an additive, at least one selected from the group consisting of a polymer compound containing a repeating unit represented by any of the following formulae (P1) to (P4) and a carboxylic acid ester compound.

[0425]

[0426] {R1 in formula (P1) is a hydrogen atom or an alkyl group;

[0427] n1 to n3 in formula (P2) are the number of repeating units, each independently an integer from 0 to 4;

[0428] R2 in formula (P3) is an alkyl group having 1 to 20 carbon atoms or a fluoroalkyl group having 1 to 20 carbon atoms;

[0429] R3 in formula (P4) is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

[0430] Such an additive is hereinafter also referred to as a "second specific additive" in this specification.

[0431] (Polymer compound)

[0432] The polymer compound used as the second specific additive is a polymer compound containing a repeating unit represented by any of the above formulae (P1) to (P4). The terminal of the polymer compound may be capped with, for example, a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted acrylate. Preferred capping groups are of the following formula:

[0433]

[0434] The substituted or unsubstituted acrylate represented by {wherein R4 is a hydrogen atom or a substituted or unsubstituted alkyl group} is particularly preferably acrylate or methacrylate.

[0435] Examples of the polymer compound having a repeating unit represented by the above formula (P1) include polyethylene glycol methyl ether acrylate and polypropylene glycol acrylate.

[0436] Examples of the polymer compound having a repeating unit represented by the above formula (P2) include polyethylene adipate (n1=1, n2=1, n3=2), poly{di(ethylene glycol) adipate} (n1=1, n2=2, n3=2), poly(1,2-butylene adipate) (n1=2, n2=1, n3=2), poly(1,4-butylene adipate) (n1=2, n2=1, n3=2), and polyethylene succinate (n1=1, n2=1, n3=1).

[0437] Examples of the polymer compound having a repeating unit represented by the above formula (P3) include poly(2,2,2-trifluoroethyl acrylate) and the like.

[0438] Examples of the polymer compound having a repeating unit represented by the formula (P4) include poly(L-lactic acid) end-capped with acrylate and 2-carboxyethyl acrylate oligomer.

[0439] The molecular weight of the polymer compound as the second specific additive is arbitrary. However, for reference, the molecular weight range of 1,000 or more and 150,000 or less can be exemplified as the value of the polystyrene-equivalent weight average molecular weight Mw obtained by gel permeation chromatography (GPC) for the polymer compound.

[0440] (Carboxylic acid ester compound)

[0441] The carboxylate compound as the second specific additive may be an alkyl ester of an organic carboxylic acid (e.g., oxalic acid, acrylic acid, methacrylic acid, etc.), wherein the alkyl group of the alkyl ester may be a straight chain, branched chain, or have a cyclic structure, may be interrupted by an oxygen atom, or may have a substituent such as a silyl group.

[0442] As the carboxylic acid ester compound, examples of oxalic acid ester include di-tert-butyl oxalate.

[0443] Examples of the acrylate include ethylene glycol methyl ether acrylate, diethylene glycol ethyl ether acrylate, 2-ethylhexyl acrylate, ethyl acrylate, n-butyl acrylate, tert-butyl acrylate, trimethylsilyl acrylate, ethyl 2-(trimethylsilylmethyl) acrylate, 2,2,2-trifluoroethyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, vinyl acrylate, propargyl acrylate, and methyl acrylate.

[0444] Examples of the methacrylate include methyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, 2,2,2-trifluoroethyl methacrylate, trimethylsilyl methacrylate, 3-(trimethoxysilyl)propyl methacrylate, 3-(trimethylsiloxy)silylpropylene methacrylate, and 3-{tris(trimethylsiloxy)silyl}propylene methacrylate.

[0445] (Preferred second specific additive)

[0446] As the second specific additive, from the viewpoint of being able to improve the cycle characteristics, long-term stability, etc. without impairing other properties of the non-aqueous secondary battery, an additive having a skeleton derived from an acryloyl group, adipic acid, or a skeleton derived from succinic acid is preferred, and more preferably at least one selected from the group consisting of polyethylene glycol methyl ether acrylate, polypropylene glycol acrylate, polyethylene adipate, poly{di(ethylene glycol) adipate}, poly(1,2-butylene adipate), polyethylene succinate, poly(2,2,2-trifluoroethyl acrylate), acrylate-terminated poly(L-lactic acid), 2-carboxyethyl acrylate oligomer, ethylene glycol methyl ether acrylate, diethylene glycol ethyl ether acrylate, 2-ethylhexyl acrylate, and n-butyl acrylate.

[0447] (Amount of the second specific additive)

[0448] The amount of the second specific additive contained in the non-aqueous electrolyte is arbitrary, for example, it can be 0.01 mass parts or more and 10.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte. If the amount of the specific additive is 0.01 mass parts or more relative to 100 mass parts of the non-aqueous electrolyte, the mechanical strength of the SEI generated on the negative electrode is sufficiently high, and a non-aqueous secondary battery with excellent cycle characteristics and long-term stable operation can be obtained even under high temperature and high voltage conditions. On the other hand, if the amount of the specific additive is 10.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte, the lithium ion conduction of the electrolyte will not be excessively hindered, and a non-aqueous secondary battery with excellent output characteristics can be obtained. The amount of the specific additive contained in the non-aqueous electrolyte can be 0.05 mass parts or more and 5.0 mass parts or less, 0.1 mass parts or more and 4.0 mass parts or less, or 0.2 mass parts or more and 3.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte.

[0449] <Method for producing non-aqueous electrolyte>

[0450] The non-aqueous electrolyte solution can be produced by mixing a non-aqueous solvent, a lithium salt, a second specific additive, and other additives as needed by any means.

[0451] <Other embodiment 3>

[0452] The present embodiment relates to a non-aqueous secondary battery in which a non-aqueous electrolyte solution contains at least one additive selected from the group consisting of organometallic hydrides and dicarbonate compounds.

[0453] Background technology and problems involved in this embodiment

[0454] In recent years, with the expansion of the large-scale power storage industry centered on electric vehicles, there has been a desire for further higher energy density of non-aqueous secondary batteries, and research and development has flourished.

[0455] Non-Patent Document 1 reports that, in a layered rock salt type positive electrode active material, the higher the Ni content, the higher the energy density.

[0456] However, for non-aqueous secondary batteries, while energy density improves, long-term durability may also deteriorate. For example, Non-Patent Document 2 discusses a unique degradation factor, stating that a higher Ni ratio leads to more rapid degradation at lower voltages. Non-Patent Document 3 reports a mechanism in which the decomposition of high-dielectric-constant solvents triggers the decomposition of lithium salts.

[0457] However, research is underway to use Si materials as negative electrode active materials instead of conventional carbon materials. This is due to the fact that the theoretical capacity of Si materials is greater than that of carbon materials.

[0458] For example, when graphite is used as the negative electrode active material, the maximum amount of lithium absorption and release per 1 mol of carbon is 1 / 6 mol, and the theoretical capacity obtained by LiC6 as the largest lithium-introducing compound is 372 mAh / g. In contrast, when Si material is used, the maximum amount of lithium absorption and release per 1 mol of Si is 3.75 mol, and the theoretical capacity obtained by LiC6 is 372 mAh / g. 3.75 The theoretical capacity of Si reaches 3600 mAh / g.

[0459] [Non-patent document 1] ACS Energy Lett., 2, 196-223 (2017).

[0460] [Non-patent document 2] J. Power Sources, 233, 121-130 (2013).

[0461] [Non-patent document 3] J. Phys. Chem. Lett., 8, 4820-4825 (2017).

[0462] However, these non-aqueous secondary batteries aiming for higher energy density may have inferior long-term durability compared to conventional non-aqueous secondary batteries, and require both the electrolyte and the electrodes to have durability under more severe environments.

[0463] Layered rock salt-type positive electrode active materials inherently contain active sites that can cause oxidative degradation of the electrolyte. These active sites can unexpectedly consume the compounds added to protect the negative electrode on the positive electrode side. Furthermore, the decomposition products of these additives, introduced and accumulated on the positive electrode side, can not only increase the internal resistance of non-aqueous secondary batteries but also accelerate the degradation of lithium salts. Furthermore, the unexpected consumption of these additives can lead to inadequate protection of the negative electrode surface.

[0464] These phenomena, which were confirmed by the results of disassembly analysis, are not described in Non-Patent Documents 1 to 3.

[0465] On the other hand, when Si material is used as the negative electrode active material, the volume change of the Si material when absorbing and releasing Li ions may become a problem.

[0466] For example, the maximum volume change of graphite when absorbing and releasing Li ions is approximately 1.2 times, whereas the use of Si can result in a larger volume change of approximately 4 times. This can make the battery mechanically fragile, and in particular, the cycle life of the negative electrode may be insufficient, which can be a significant obstacle to practical use.

[0467] Effects of this embodiment

[0468] According to this embodiment, first, a non-aqueous electrolyte and a non-aqueous secondary battery are provided that suppress the active sites of the positive electrode active material that cause oxidative degradation of the non-aqueous electrolyte, exhibit excellent load characteristics, and can suppress various degradation phenomena during high-temperature storage or repeated charge and discharge cycles.

[0469] According to the present embodiment, a non-aqueous electrolyte and a non-aqueous secondary battery are provided that can suppress various degradation phenomena associated with volume changes of the negative electrode during repeated charge and discharge cycles when Si material is used as the negative electrode active material.

[0470] <Third Specific Additive>

[0471] The non-aqueous electrolyte solution of the present embodiment contains at least one additive selected from the group consisting of organometallic hydrides and dicarbonate compounds.

[0472] The at least one additive selected from the group consisting of organometallic hydrides and dicarbonate compounds is hereinafter also referred to as a "third specific additive" in this specification.

[0473] (Organometallic Hydride)

[0474] The central metal of the organometallic hydride serving as the third specific additive may be, for example, a metalloid (semimetal) such as boron or silicon, or a late transition metal such as tin. Furthermore, the organometallic hydride may further contain a metal selected from metals other than the central metal, metalloids, and late transition metals.

[0475] Examples of organometallic hydrides in which the central metal is boron include sodium cyanoborohydride (Na + ·[HBCN] - ), sodium tris(1,1,1,3,3,3-hexafluoroisopropyl)borohydride (Na + [HB(OCH(CF3)2)3] -) etc. These organometallic hydrides are anion-cation pairs.

[0476] Examples of organometallic hydrides in which the central metal is silicon include phenylsilane (H3SiC6H5) and 10-undecenylsilane (H3Si(CH2)9CH=CH2). These organometallic hydrides are molecular.

[0477] Examples of the organometallic hydride in which the central metal is tin include tri-n-butyltin hydride (HSn((CH 2 ) 3 CH 3 ) 3 ).

[0478] (Dicarbonate Compound)

[0479] The dicarbonate compound as the third specific additive may be, for example, a compound represented by the following formula (C1).

[0480]

[0481] {In formula (C1), R1 and R2 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 5 to 20 carbon atoms, a hydride ion, a halogen atom, a hydroxyl group, a thiol group, an imino group, a carboxyl group, an alkylcarbonyloxy group, a cyano group, an N-substituted amino group, an alkylcarbonylamino group, an N-substituted alkylcarbonylamino group, an alkenylcarbonylamino group, an N-substituted alkenylcarbonylamino group, an alkynylcarbonylamino group, an N-substituted alkynylcarbonylamino group, an arylcarbonylamino group, an N-substituted arylcarbonylamino group, a boron atom-containing group, an aluminum atom-containing group, a silicon atom-containing group, a phosphorus atom-containing group, or a sulfur atom-containing group.}

[0482] In the above formula (C1), R1 and R2 are preferably each an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted aryl group.

[0483] The dicarbonate compound is preferably at least one selected from the group consisting of diallyl dicarbonate, dimethyl dicarbonate, diethyl dicarbonate, and dibenzyl dicarbonate.

[0484] (Amount of the third specific additive)

[0485] The amount of the third specific additive contained in the non-aqueous electrolyte is arbitrary, for example, it can be 0.01 mass parts or more and 10.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte. If the amount of the specific additive is 0.01 mass parts or more relative to 100 mass parts of the non-aqueous electrolyte, the mechanical strength of the SEI generated on the negative electrode is sufficiently high, and a non-aqueous secondary battery with excellent cycle characteristics and long-term stable operation can be obtained. On the other hand, if the amount of the specific additive is 10.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte, the lithium ion conduction of the electrolyte will not be excessively hindered, and a non-aqueous secondary battery with excellent output characteristics can be obtained. The amount of the specific additive contained in the non-aqueous electrolyte can be 0.05 mass parts or more and 5.0 mass parts or less, 0.1 mass parts or more and 4.0 mass parts or less, or 0.2 mass parts or more and 3.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte.

[0486] <Method for producing non-aqueous electrolyte>

[0487] The non-aqueous electrolyte solution can be produced by mixing a non-aqueous solvent, a lithium salt, a third specific additive, and other additives as needed by any means.

[0488] <Other embodiment 4>

[0489] The present embodiment relates to a non-aqueous secondary battery in which a non-aqueous electrolyte solution includes a silyl group-containing additive.

[0490] Background technology and problems involved in this embodiment

[0491] In recent years, with the expansion of the large-scale power storage industry centered on electric vehicles, there has been a desire for further higher energy density of non-aqueous secondary batteries, and research and development has flourished.

[0492] Non-Patent Document 1 reports that, in a layered rock salt type positive electrode active material, the higher the Ni content, the higher the energy density.

[0493] However, for non-aqueous secondary batteries, while energy density improves, long-term durability may also deteriorate. For example, Non-Patent Document 2 discusses a unique degradation factor, stating that a higher Ni ratio leads to more rapid degradation at lower voltages. Non-Patent Document 3 reports a mechanism in which the decomposition of high-dielectric-constant solvents triggers the decomposition of lithium salts.

[0494] However, research is underway to use Si materials as negative electrode active materials instead of conventional carbon materials. This is due to the fact that the theoretical capacity of Si materials is greater than that of carbon materials.

[0495] For example, when graphite is used as the negative electrode active material, the maximum amount of lithium absorption and release per 1 mol of carbon is 1 / 6 mol, and the theoretical capacity obtained by LiC6 as the largest lithium-introducing compound is 372 mAh / g. In contrast, when Si material is used, the maximum amount of lithium absorption and release per 1 mol of Si is 3.75 mol, and the theoretical capacity obtained by LiC6 is 372 mAh / g. 3.75 The theoretical capacity of Si reaches 3600 mAh / g.

[0496] [Non-patent document 1] ACS Energy Lett., 2, 196-223 (2017).

[0497] [Non-patent document 2] J. Power Sources, 233, 121-130 (2013).

[0498] [Non-patent document 3] J. Phys. Chem. Lett., 8, 4820-4825 (2017).

[0499] However, these non-aqueous secondary batteries aiming for higher energy density may have inferior long-term durability compared to conventional non-aqueous secondary batteries, and require both the electrolyte and the electrodes to have durability under more severe environments.

[0500] Layered rock salt-type positive electrode active materials inherently contain active sites that can cause oxidative degradation of the electrolyte. These active sites can unexpectedly consume the compounds added to protect the negative electrode on the positive electrode side. Furthermore, the decomposition products of these additives, introduced and accumulated on the positive electrode side, can not only increase the internal resistance of non-aqueous secondary batteries but also accelerate the degradation of lithium salts. Furthermore, the unexpected consumption of these additives can lead to inadequate protection of the negative electrode surface.

[0501] These phenomena, which were confirmed by the results of disassembly analysis, are not described in any of Non-Patent Documents 1 to 3.

[0502] Repeated charge and discharge in non-aqueous secondary batteries can lead to the gradual generation of gas within the battery. This gas is believed to be generated by the decomposition of components of the non-aqueous electrolyte at the electrodes. Therefore, a search is underway for non-aqueous electrolytes that suppress the decomposition of non-aqueous electrolyte components at the electrodes during charge and discharge, thereby reducing gas generation.

[0503] Furthermore, non-aqueous secondary batteries may suffer from problems such as a decrease in capacity when used in a low-temperature environment and a deterioration in battery performance due to charging in a low-temperature environment, and thus improvement in low-temperature performance is required.

[0504] Furthermore, since a high operating voltage of a secondary battery is advantageous, non-aqueous secondary batteries capable of high-voltage operation have been explored. However, if a secondary battery using a conventional non-aqueous solvent is subjected to high-voltage operation, the battery performance may deteriorate rapidly due to repeated charge and discharge cycles.

[0505] On the other hand, when Si material is used as the negative electrode active material, the volume change of the Si material when absorbing and releasing Li ions may become a problem.

[0506] For example, the maximum volume change of graphite when absorbing and releasing Li ions is approximately 1.2 times, while using Si can result in a larger volume change of approximately 4 times. This makes the battery mechanically fragile, and the cycle life of the negative electrode in particular is insufficient, which is a major obstacle to practical use.

[0507] Effects of this embodiment

[0508] According to this embodiment, the first aspect provides an active point of a positive electrode active material that suppresses oxidative degradation of a non-aqueous electrolyte, exhibits excellent load characteristics, and can suppress various degradation phenomena (especially capacity reduction and gas generation) during repeated charge and discharge cycles, and has excellent low-temperature characteristics and is capable of high-voltage operation. Non-aqueous electrolyte and non-aqueous secondary battery.

[0509] According to the present embodiment, a non-aqueous electrolyte and a non-aqueous secondary battery are provided that can suppress various degradation phenomena associated with volume changes of the negative electrode during repeated charge and discharge cycles when Si material is used as the negative electrode active material.

[0510] <Fourth Specified Additive>

[0511] The non-aqueous electrolyte solution of the present embodiment contains a silyl group-containing additive.

[0512] The silyl group-containing additive in this embodiment has the function of promoting the formation of SEI on the positive electrode of the non-aqueous secondary battery and suppressing the oxidative decomposition of the non-aqueous electrolyte.

[0513] Such a silyl group-containing additive may also be referred to as a "fourth specific additive" hereinafter in this specification.

[0514] Preferred examples of the silyl group-containing additive include at least one selected from the group consisting of a compound represented by the following formula (S1) and a polymer compound containing a repeating unit represented by the following formula (S2).

[0515]

[0516] {In formula (S1), R is independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 5 to 20 carbon atoms; X is O, S, or NH; Z is P, P═O, B, or Si; when Z is P or P═O, n1 is 1, n2 is an integer from 1 to 3, and n2+n3=3; when Z is B, n1 is 1, n2 is an integer from 1 to 3, and n2+n3=3; when Z is Si, n1 is 0, n2 is an integer from 1 to 4, and n2+n3=4.}

[0517]

[0518] {R in formula (S2) has the same meaning as R in formula (S1).}

[0519] R in the above formula (S1) is preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, more preferably an unsubstituted alkyl group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms substituted by a halogen atom, further preferably an alkyl group having 1 to 6 or 1 to 4 carbon atoms, or a fluoroalkyl group having 1 to 6 or 1 to 4 carbon atoms, particularly preferably a methyl group or a 2,2,2-trifluoroethyl group.

[0520] X is preferably an oxygen atom.

[0521] Specific examples of the compound wherein Z in the formula (S1) is P include tris(trimethylsilyl)phosphate and the like.

[0522] Specific examples of the compound wherein Z is P═O include mono(trimethylsilyl) phosphite, tri(trimethylsilyl) phosphite, and tris(2,2,2-trifluoroethyl) phosphite.

[0523] Specific examples of the compound wherein Z is B include tris(trimethylsilyl) borate and tris(2,2,2-trifluoroethylsilyl) borate.

[0524] Specific examples of the compound in which Z is Si include tris(trimethylsilyl)silane and the like.

[0525] Specific examples of the polymer compound containing the repeating unit represented by the above formula (S2) include trimethylsilyl polyphosphate and the like.

[0526] (Amount of the fourth specific additive)

[0527] The amount of the 4th specific additive (silyl-containing additive) contained in the non-aqueous electrolyte is arbitrary, for example, it can be 0.01 parts by mass or more and 10.0 parts by mass or less relative to 100 parts by mass of the non-aqueous electrolyte. If the amount of the silyl-containing additive is 0.01 parts by mass or more relative to 100 parts by mass of the non-aqueous electrolyte, the mechanical strength of the SEI generated on the positive electrode is sufficiently high, and the generation of gas accompanying charge and discharge can be suppressed, the cycle characteristics are excellent, and the non-aqueous secondary battery capable of long-term stable operation can be obtained. On the other hand, if the amount of the silyl-containing additive is 10.0 parts by mass or less relative to 100 parts by mass of the non-aqueous electrolyte, the lithium ion conduction of the electrolyte will not be excessively hindered, and a non-aqueous secondary battery with excellent output characteristics can be obtained. The amount of the silyl group-containing additive contained in the nonaqueous electrolyte solution may be 0.05 to 5.0 parts by mass, 0.1 to 4.0 parts by mass, or 0.2 to 3.0 parts by mass relative to 100 parts by mass of the nonaqueous electrolyte solution.

[0528] Other additives

[0529] The non-aqueous electrolyte solution may contain other additives together with the silyl group-containing additive.

[0530] Examples of other additives contained in the non-aqueous electrolyte include heterocyclic compounds and acid anhydrides.

[0531] (Heterocyclic compound)

[0532] The heterocyclic compound has a function of forming a protective layer on the negative electrode active material layer and suppressing reductive decomposition of the non-aqueous electrolyte.

[0533] The heterocyclic compound may be a polycyclic compound, and preferably may be selected from compounds having a deformed 3- to 7-membered ring and a spiro compound.

[0534] Specific examples of the heterocyclic compound include 1,3-propane sultone, 1-propylene 1,3-sultone, 1,4-butane sultone, maleic anhydride, succinic anhydride, maleimide, ε-caprolactam, and vinylene carbonate. It is preferred to use one or more selected from these.

[0535] The heterocyclic compound is preferably a heterocyclic compound that has high reactivity with nucleophilic species and radical anions and can form a uniform protective film (SEI). From this viewpoint, a heterocyclic 5-membered ring compound is preferred. Specifically, it is particularly preferred to use one selected from 1,3-propane sultone, 1-propylene 1,3-sultone, maleic anhydride, and maleimide.

[0536] The amount of the heterocyclic compound contained in the non-aqueous electrolyte is arbitrary, for example, it can be 0.01 mass parts or more and 10.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte. The amount of the heterocyclic compound contained in the non-aqueous electrolyte can be 0.05 mass parts or more and 5.0 mass parts or less, 0.1 mass parts or more and 4.0 mass parts or less, or 0.2 mass parts or more and 3.0 mass parts or less relative to 100 mass parts of the non-aqueous electrolyte.

[0537] (anhydride)

[0538] The acid anhydride is as described above.

[0539] <Method for producing non-aqueous electrolyte>

[0540] The non-aqueous electrolyte solution can be produced by mixing a non-aqueous solvent, a lithium salt, a fourth specific additive (a silyl group-containing additive), and other additives as needed by any means.

[0541] <Other embodiment 5>

[0542] The present embodiment relates to a non-aqueous secondary battery in which a non-aqueous electrolyte solution includes an additive containing a boron atom.

[0543] Background technology and problems involved in this embodiment

[0544] In recent years, with the expansion of the large-scale power storage industry centered on electric vehicles, there has been a desire for further higher energy density of non-aqueous secondary batteries, and research and development has flourished.

[0545] Non-Patent Document 1 reports that, in a layered rock salt type positive electrode active material, the higher the Ni content, the higher the energy density.

[0546] However, for non-aqueous secondary batteries, while energy density improves, long-term durability may also deteriorate. For example, Non-Patent Document 2 discusses a unique degradation factor, stating that a higher Ni ratio leads to more rapid degradation at lower voltages. Non-Patent Document 3 reports a mechanism in which the decomposition of high-dielectric-constant solvents triggers the decomposition of lithium salts.

[0547] However, research is underway to use Si materials as negative electrode active materials instead of conventional carbon materials. This is due to the fact that the theoretical capacity of Si materials is greater than that of carbon materials.

[0548] For example, when graphite is used as the negative electrode active material, the maximum amount of lithium absorption and release per 1 mol of carbon is 1 / 6 mol, and the theoretical capacity obtained by LiC6 as the largest lithium-introducing compound is 372 mAh / g. In contrast, when Si material is used, the maximum amount of lithium absorption and release per 1 mol of Si is 3.75 mol, and the theoretical capacity obtained by LiC6 is 372 mAh / g. 3.75 The theoretical capacity of Si reaches 3600 mAh / g.

[0549] [Non-patent document 1] ACS Energy Lett., 2, 196-223 (2017).

[0550] [Non-patent document 2] J. Power Sources, 233, 121-130 (2013).

[0551] [Non-patent document 3] J. Phys. Chem. Lett., 8, 4820-4825 (2017).

[0552] However, these non-aqueous secondary batteries aiming for higher energy density may have inferior long-term durability compared to conventional non-aqueous secondary batteries, and require both the electrolyte and the electrodes to have durability under more severe environments.

[0553] Layered rock salt-type positive electrode active materials inherently contain active sites that can cause oxidative degradation of the electrolyte. These active sites can unexpectedly consume the compounds added to protect the negative electrode on the positive electrode side. Furthermore, the decomposition products of these additives, introduced and accumulated on the positive electrode side, can not only increase the internal resistance of non-aqueous secondary batteries but also accelerate the degradation of lithium salts. Furthermore, the unexpected consumption of these additives can lead to inadequate protection of the negative electrode surface.

[0554] These phenomena, which were confirmed by the results of disassembly analysis, are not described in Non-Patent Documents 1 to 3.

[0555] Furthermore, non-aqueous secondary batteries may suffer from problems such as a decrease in capacity when used in a low-temperature environment and a deterioration in battery performance due to charging in a low-temperature environment, and thus improvement in low-temperature performance is required.

[0556] Effects of this embodiment

[0557] According to this embodiment, the first aspect provides a non-aqueous electrolyte and a non-aqueous secondary battery that suppresses the active points of the positive electrode active material that causes oxidative degradation of the non-aqueous electrolyte, exhibits excellent load characteristics, and can suppress various degradation phenomena during high-temperature storage or repeated charge and discharge cycles, and has excellent low-temperature characteristics.

[0558] According to the present embodiment, a non-aqueous electrolyte and a non-aqueous secondary battery are provided that can suppress various degradation phenomena associated with volume changes of the negative electrode during repeated charge and discharge cycles when Si material is used as the negative electrode active material.

[0559] <Fifth Specified Additive>

[0560] The non-aqueous electrolyte solution of the present embodiment contains an additive containing a boron atom.

[0561] The boron-containing additive in this embodiment is a strong electrophilic reagent, preferably a boron-containing additive that easily reacts with the decomposition intermediate of the non-aqueous electrolyte and can form a strong, thin-film SEI on the negative electrode. From this point of view, the boron-containing additive preferably has a BO bond, more preferably contains a BO bond and a fluorine atom, or a heterocyclic ring having a boron atom and an oxygen atom as ring atoms.

[0562] Such a boron atom-containing additive may be hereinafter referred to as a "fifth specific additive" in this specification.

[0563] Preferred examples of the boron atom-containing additive include at least one selected from the group consisting of a compound represented by the following formula (B1) and a compound represented by the following formula (B2).

[0564]

[0565] {In formula (B1), R 1 Each independently represents a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkenyl group having 2 to 20 carbon atoms, a fluoroalkynyl group having 2 to 20 carbon atoms, a fluoroaryl group having 5 to 20 carbon atoms, or a fluoroacyl group having 2 to 20 carbon atoms.

[0566]

[0567] {In formula (B2), R 2 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 5 to 20 carbon atoms; n1 represents an integer from 1 to 6, n2 represents 2×n1; n3 represents an integer from 2 to 6, n4 represents 2×n3; and n5 represents 0 or 1.

[0568] In the above formula (B1), R 1 , preferably a fluoroalkyl group having 1 to 20 carbon atoms, preferably a fluoroalkyl group having 1 to 6 carbon atoms, more preferably a fluoroalkyl group having 1 to 4 carbon atoms, particularly preferably a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 1,2,2,2-tetrafluoroethyl group, a perfluoroethyl group, or a 1,1,1,3,3,3-hexafluoroisopropyl group.

[0569] Specific examples of the compound represented by formula (B1) include tris(2,2,2-trifluoroethyl) borate, tris(1,1,1,3,3,3-hexafluoroisopropyl) borate, and tris(trifluoroacetoxy)borane.

[0570] In the above formula (B2), R 2 , preferably a hydrogen atom. Therefore, as C n1 R 2 n2 or C n3 R 2 n4 The divalent group shown is preferably a methylene group, an alkylmethylene group, a dialkylmethylene group, or a linear or branched alkylene group, and particularly preferably a trimethylene group or a 2,2-dimethyltrimethylene group.

[0571] Specific examples of the compound represented by the formula (B2) include bis(neopentyl glycolide)diboron and bis(trimethylene)diborate.

[0572] (Amount of the fifth specific additive)

[0573] The amount of the 5th specific additive (boron atom-containing additive) contained in the non-aqueous electrolyte is arbitrary, for example, relative to 100 parts by mass of non-aqueous electrolyte, it can be 0.01 parts by mass or more and 10.0 parts by mass or less. If the amount of the boron atom-containing additive is 0.01 parts by mass or more relative to 100 parts by mass of non-aqueous electrolyte, the mechanical strength of the SEI generated on the negative electrode is sufficiently high, and it is possible to obtain a non-aqueous secondary battery with excellent cycle characteristics and excellent low-temperature characteristics while being able to operate stably for a long time. On the other hand, if the amount of the boron atom-containing additive is 10.0 parts by mass or less relative to 100 parts by mass of non-aqueous electrolyte, the lithium ion conduction of the electrolyte will not be excessively hindered, and it is possible to obtain a non-aqueous secondary battery with excellent output characteristics and low-temperature characteristics. The amount of the boron atom-containing additive contained in the nonaqueous electrolyte solution may be 0.05 to 5.0 parts by mass, 0.1 to 4.0 parts by mass, or 0.2 to 3.0 parts by mass relative to 100 parts by mass of the nonaqueous electrolyte solution.

[0574] <Method for producing non-aqueous electrolyte>

[0575] The non-aqueous electrolyte solution can be produced by mixing a non-aqueous solvent, a lithium salt, the fifth specific additive (boron atom-containing additive), and other additives as needed by any means.

[0576] Example

[0577] <Example (Part 1)>

[0578] [Production of positive electrode]

[0579] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.5 Mn 0.3 Co 0.2 O2), acetylene black powder as a conductive additive, and polyvinylidene fluoride (PVDF) as a binder were mixed in a mass ratio of 93.9:3.3:2.8 to obtain a positive electrode mixture.

[0580] N-methyl-2-pyrrolidone was added as a solvent to the obtained positive electrode mixture and further mixed to prepare a slurry containing the positive electrode mixture. The slurry containing the positive electrode mixture had a unit area weight of about 9.3 mg / cm 2 The positive electrode active material layer was coated on one side of a 15 μm thick aluminum foil, which served as the positive electrode current collector, while being adjusted in a manner. When the slurry containing the positive electrode mixture was applied to the aluminum foil, an uncoated area was formed so that a portion of the aluminum foil was exposed. Then, the positive electrode active material layer was rolled to a density of 2.7 g / cm 3 The positive electrode is rolled in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode collector.

[0581] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 30 mm x 50 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were welded to the exposed portion of the aluminum foil, and the product was vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[0582] [Production of negative electrode]

[0583] Graphite as a negative electrode active material, carboxymethyl cellulose as a binder, and styrene-butadiene rubber latex also as a binder were mixed at a mass ratio of 97.4:1.1:1.5 to obtain a negative electrode mixture.

[0584] After adding an appropriate amount of water to the obtained negative electrode mixture and mixing thoroughly, a slurry containing the negative electrode mixture was prepared. The slurry had a unit area weight of about 5.9 mg / cm 2 The negative electrode active material layer was coated on one side of a 10 μm thick copper foil at a constant thickness while being adjusted in a manner. When the negative electrode mixture slurry was applied to the copper foil, an uncoated area was formed so that a portion of the copper foil was exposed. Then, the negative electrode active material layer was roll-pressed to a density of 1.4 g / cm 3 The negative electrode is rolled in a manner as shown in FIG. , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector.

[0585] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​32 mm x 52 mm, including the exposed portion of the copper foil. A nickel lead for current extraction was then welded to the exposed portion of the copper foil. The product was then vacuum-dried at 80°C for 12 hours to obtain a negative electrode with leads.

[0586] [Battery production]

[0587] [Assembly of single-layer laminated batteries]

[0588] The positive electrode with a lead and the negative electrode with a lead are overlapped with a polyethylene microporous membrane separator (film thickness 21μm, air permeability 285s / 100cc, porosity 41%) in a manner that the mixture coating surfaces of each pole face each other to form a stacked electrode body. The stacked electrode body is housed in a 90mm×80mm aluminum laminate sheet outer shell and vacuum dried at 80°C for 5 hours to remove moisture. Then, after the above-mentioned electrolyte solutions are injected into the outer shell, the outer shell is sealed to produce a single-layer laminated (bag-type) non-aqueous secondary battery (hereinafter also referred to as a "single-layer laminated battery"). The design capacity value of the single-layer laminated battery is 23mAh and the rated voltage value is 4.2V.

[0589] [Evaluation of single-layer laminated batteries]

[0590] The evaluation cells obtained as described above were first charged according to the following procedure (1-1). Each cell was then evaluated according to the procedures (1-2), (1-3), and (1-4). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[0591] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[0592] (1-1) Initial charge and discharge treatment of single-layer laminated batteries

[0593] The battery's ambient temperature was set at 25°C. After charging to 4.2V at a constant current of 2.3mA (equivalent to 0.1C), it was charged at a constant voltage of 4.2V until the current decayed to 0.05C. It was then discharged to 2.5V at a constant current of 6.9mA (equivalent to 0.3C).

[0594] (1-2) Output test of single-layer laminated battery

[0595] For the battery that had undergone the initial charge and discharge process using the method described in (1-1) above, the ambient temperature of the battery was set to 25°C. After charging to 4.2V at a constant current of 23mA (equivalent to 1C), charging was continued at a constant voltage of 4.2V until the current decayed to 0.05C. The battery was then discharged to 3.0V at a current of 23mA (equivalent to 1C). The same charge and discharge process was repeated except that the current value during the constant current discharge was changed to 230mA (equivalent to 10C). The capacity retention rate was calculated using the following formula.

[0596] Capacity retention rate = (capacity at 10C discharge / capacity at 1C discharge) × 100 [%]

[0597] (1-3) Single-layer laminate battery charge and discharge cycle test at -10℃

[0598] A cycle test was performed on the battery that had been subjected to the first charge and discharge treatment using the method described in (1-1) above. It should be noted that the cycle test was started 3 hours after the ambient temperature of the battery was set to -10°C. First, after charging at a constant current of 4.6mA equivalent to 0.2C to reach 4.2V, it was charged at a constant voltage of 4.2V until the current decayed to 0.05C. Then, it was discharged at a constant current of 4.6mA equivalent to 0.2C to 2.5V. This process of charging and discharging once each was considered as one cycle, and 40 cycles of charging and discharging were performed. The discharge capacity of the 40th cycle when the discharge capacity of the first cycle was set to 100% was used as the capacity retention rate.

[0599] (1-4) Charge-discharge cycle test of single-layer laminated battery at 25°C

[0600] For the battery that was first charged and discharged using the method described in (1-1) above, the ambient temperature of the battery was set to 25°C. After charging to 4.2V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.2V until the current decayed to 0.05C. Then, it was discharged to 3V at a constant current of 23mA. This process of charging and discharging once each was considered one cycle, and 100 cycles of charging and discharging were performed. The discharge capacity of the 100th cycle when the discharge capacity of the first cycle was set to 100% was used as the capacity retention rate.

[0601] [Analysis of the components of the negative electrode protective film]

[0602] Since the negative electrode protective film of this example is poorly soluble in non-aqueous electrolytes, its solubility in organic solvents is also low. Therefore, heavy water was used to extract the negative electrode protective film. Furthermore, as a method for analyzing the components of the negative electrode protective film, the compounds represented by the aforementioned general formulas (1) to (3) were measured using NMR, and the compounds represented by the aforementioned general formulas (4) to (6) were measured using LC-MS.

[0603] (Extraction of electrode coating)

[0604] For the battery that had undergone the initial charge-discharge process using the method described in (1-1) above, disassemble the battery under an argon atmosphere, place the negative electrode in a screw-threaded glass tube, inject 2 mL of deuterated water into each vial using a syringe, and seal with a cap. After standing for 72 hours to extract the electrode coating, filter through a Pasteur pipette filled with glass wool to obtain an extract.

[0605] (LC-MS determination)

[0606] The extract was further diluted 10-fold with distilled water, centrifuged (12,000 rpm, 15 minutes) to remove the solid content, and then subjected to LC-MS analysis.

[0607] The measuring device was used by connecting a UPLC liquid chromatograph manufactured by Japan Waters Corporation and a SYNAPT G2 mass spectrometer manufactured by Japan Waters Corporation. The chromatographic column used was ACQUITY UPLC BEH C18 (1.7 μm, 2.1 mm×50 mm) manufactured by Japan Waters Corporation. The column temperature was set to 40°C and the flow rate was set to 0.3 mL per minute. The detector used a photodiode array (200-400 nm). Water containing 0.1% by volume of formic acid was used as phase A of the mobile phase, and acetonitrile containing 0.1% by volume of formic acid was used as phase B, and gradient elution was performed as described below. The sample injection volume was set to 1 μL.

[0608] [Table 1]

[0609] Time / minute Phase A (volume %) Phase B (volume %) 0 98 2 10 0 100 10.1 98 2 15 98 2

[0610] In the mass spectrometer, electrospray ionization (ESI+ and ESI-) was used for ionization, and the m / z scanning range was set to 50 to 1200.

[0611] The peak area (X) per 1 μg of the active substance was calculated by the following mathematical formula.

[0612] (X) = Peak area value (actual measured value) × diluted extract volume × 1000 / LC-MS injection volume / (electrode mass excluding current collector × active material ratio) [peak area / μg]

[0613] The diluted extract amount is calculated by multiplying the amount of heavy water by the distilled water dilution ratio of the extract.

[0614] The concentration of the negative electrode protective film component per 1 g of the active material in this example was calculated by the following measurement method.

[0615] (NMR measurement)

[0616] The obtained extract was added to an NMR tube with a diameter of 3 mm and sealed. Separately, tetrafluorobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved as a standard substance in deuterated chloroform (manufactured by Sigma-Aldrich Co., LLC) containing tetramethylsilane as a chemical shift standard and added to an NMR tube with a diameter of 5 mm. The above-mentioned 3 mm NMR tube was inserted into the NMR tube and the double tube method was used for the measurement. 1 H NMR measurement. In addition, as a quantitative standard substance, a heavy aqueous solution of dimethyl sulfoxide (concentration 0.398 mg / mL) was prepared and the same 1 H NMR determination.

[0617] The measurement apparatus used was a JNM-ECS-400 FT NMR instrument manufactured by JEOL Resonance Co., Ltd. Deuterated chloroform was used as the lock solvent, the accumulation frequency was set to 256 times, and tetramethylsilane (0 ppm) was used as the chemical shift reference. Quantitative calculations involved setting the integral value of the peak attributed to protons of tetrafluorobenzene to 2000, and calculating the integral value per unit concentration equivalent to one proton from the integral value of the signal of dimethyl sulfoxide, a reference substance. This value was used to calculate the concentration in the extract from the integral value of each peak.

[0618] The concentration (Y) of the negative electrode protective film component per 1 g of the active material was calculated by the following mathematical formula.

[0619] (Y) = [concentration in extract D × amount of heavy water C / (mass of electrode excluding current collector A × active material ratio B)] / 1000 [mg / g]

[0620] The ion conductivity of the electrolyte solution of this example was calculated by the following measurement method.

[0621] (Ionic conductivity measurement)

[0622] The electrolyte was placed in a sealed cell (24 mm diameter x 0.35 mm thick) manufactured by TOYO Corporation, sealed, and inserted into a holder (SH1-Z) and connected. The cell was then placed in a thermostatic bath for AC impedance measurement. Gold electrodes were used. The entire process, from electrolyte collection to filling and sealing the sealed cell, was performed in an Ar glove box.

[0623] The film thickness, porosity, and air permeability of the polyethylene microporous film of this example were calculated by the following measurement methods.

[0624] (film thickness)

[0625] The thickness was measured at room temperature (23±2°C) using a micro thickness gauge, KBM (trademark), manufactured by Toyo Seiki.

[0626] (Porosity)

[0627] Cut a 10cm x 10cm square sample and calculate its volume (cm 3 ) and mass (g), which are then combined with the film density (g / cm 3 ) is calculated using the following formula.

[0628] Porosity = (volume - mass / membrane density) / volume × 100

[0629] It should be noted that the film density was fixed at 0.95 for calculation.

[0630] (air permeability)

[0631] The density was measured using a Gurley densometer (G-B2 (trademark) manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS P-8117.

[0632] [Example 1]

[0633] Under an inert atmosphere, acetonitrile (AcN), diethyl carbonate (DEC), ethylene carbonate (EC) and vinylene carbonate (VC) were mixed in a volume ratio of 49:28:21:2. Furthermore, relative to 1L of the mixed solution, 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) were dissolved, and as additives, 0.2% by mass of succinic anhydride (SAH) and 0.25% by mass of 1-methyl-1H-benzotriazole (MBTA) were added and mixed to obtain an electrolyte. For the obtained electrolyte, it was visually confirmed that the lithium salt and the additive were completely dissolved. For this electrolyte, after the non-aqueous secondary battery of Example 1 was prepared by the method described in (1-1) above, it was measured by the steps described in (1-2) to (1-4) above, the LC-MS measurement of the negative electrode and the NMR measurement.

[0634] [Example 2]

[0635] Under an inert atmosphere, acetonitrile (AcN), diethyl carbonate (DEC), ethylene carbonate (EC) and vinylene carbonate (VC) were mixed in a volume ratio of 47:28:21:4. Furthermore, relative to 1L of the mixed solution, 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) were dissolved, and as additives, 0.2% by mass of succinic anhydride (SAH) and 0.25% by mass of 1-methyl-1H-benzotriazole (MBTA) were added and mixed to obtain an electrolyte. For the obtained electrolyte, it was visually confirmed that the lithium salt and the additives were completely dissolved. For this electrolyte, after the non-aqueous secondary battery of Example 2 was prepared by the method described in (1-1) above, it was measured by the steps described in (1-2) to (1-4), the LC-MS measurement of the negative electrode and the NMR measurement.

[0636] [Comparative Example 1]

[0637] In an inert atmosphere, diethyl carbonate (DEC), ethylene carbonate (EC) and vinylene carbonate (VC) were mixed in a volume ratio of 68:30:2. Furthermore, 1.0 mol of lithium hexafluorophosphate (LiPF6) was dissolved with respect to 1 L of the mixed solution to obtain an electrolyte. For the obtained electrolyte, it was visually confirmed that all the lithium salts were dissolved. For this electrolyte, the non-aqueous secondary battery of Comparative Example 1 was prepared using the method described in (1-1) above, and then measured by the steps described in (1-2) to (1-4) and the LC-MS measurement of the negative electrode.

[0638] [Comparative Example 2]

[0639] In an inert atmosphere, acetonitrile (AcN), diethyl carbonate (DEC), ethylene carbonate (EC) and vinylene carbonate (VC) were mixed in a volume ratio of 47:28:21:4. Furthermore, 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) were dissolved with respect to 1 L of the mixed solution to obtain an electrolyte. For the obtained electrolyte, it was visually confirmed that all the lithium salts were dissolved. For this electrolyte, the non-aqueous secondary battery of Comparative Example 2 was prepared using the method described in (1-1) above, and then measured by the steps described in (1-2) to (1-4) and the LC-MS of the negative electrode.

[0640] Table 2 below shows the constituent components and electrolyte compositions of the non-aqueous secondary batteries of Examples 1 and 2 and Comparative Examples 1 and 2.

[0641] [Table 2]

[0642]

[0643] Table 3 below shows the ion conductivities of the non-aqueous electrolyte solutions of Examples 1 and 2 and Comparative Examples 1 and 2 at 20°C.

[0644] [Table 3]

[0645]

[0646] Table 4 below shows the output test, -10°C charge-discharge cycle test, and 25°C charge-discharge cycle test results for Examples 1 and 2 and Comparative Examples 1 and 2. For the -10°C charge-discharge cycle test and the 25°C charge-discharge cycle test, batteries with a capacity retention rate of 80% or higher are marked with a circle, while batteries with a capacity retention rate of less than 80% are marked with an x.

[0647] [Table 4]

[0648]

[0649] As shown in Table 4, in the -10°C cycle test, the capacity retention rates for Examples 1 and 2 were all above 80%. On the other hand, the battery short-circuited in Comparative Example 1. This is believed to be due to the low ionic conductivity, which caused lithium ions to precipitate as dendrites on the negative electrode, leading to the short-circuit. For Comparative Example 2, the durability in the 50°C cycle test was less than 75%.

[0650] Table 5 below shows the LC-MS results of the negative electrode extracts in Examples 1 and 2 and Comparative Examples 1 and 2.

[0651] [Table 5]

[0652]

[0653] As shown in Table 5 above, for Example 1 and Example 2, the results of LC-MS measurement showed that a compound with a molecular weight of 117 was detected in ESI-. The molecular weight of the compound composed of R2 in formula (4) being an H atom and n being 2 is 118. In this measurement, it is detected as the molecular weight in which the hydrogen ion is detached and ionized, so it is consistent with the molecular weight detected in this measurement. For Comparative Example 1 and Comparative Example 2, no compound with a molecular weight of 117 was detected. This result confirmed that for Examples 1 to 2, the negative electrode contained a compound represented by the compound composed of R2 in formula (1) being an H atom and n being 2. In addition, PF6 anions with a molecular weight of 149 and N(SO2F)2 anions with a molecular weight of 179.92 were also confirmed.

[0654] In addition, the NMR results of the negative electrode extracts in Examples 1 and 2 are shown in Tables 6 and 7 below.

[0655] [Table 6]

[0656]

[0657] [Table 7]

[0658]

[0659] As shown in Tables 6 and 7, the compounds represented by the general formulae (1) to (3) were confirmed in Examples 1 and 2 based on the results of NMR measurements.

[0660] <Example (Part 2)>

[0661] Fabrication of coin-type non-aqueous secondary batteries

[0662] [Production of positive electrode]

[0663] A composite oxide of lithium, nickel, manganese, and cobalt (LiNi) with a number average particle size of 11 μm as the positive electrode active material (A) was prepared. 1 / 3Mn 1 / 3 Co 1 / 3 O2, density 4.70g / cm 3 ), graphite powder with a number average particle size of 6.5 μm (density 2.26 g / cm 3 ) and acetylene black powder with a number average particle size of 48 nm (density 1.95 g / cm 3 ), and (C) polyvinylidene fluoride (PVDF, density 1.75 g / cm 3 ) were mixed in a mass ratio of 92:4:4 to obtain a positive electrode mixture.

[0664] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture in a manner that the solid content is 68% by mass, and further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, a three-roll mill transfer coater is used to coat a single side of an aluminum foil with a thickness of 15 μm and a width of 280 mm, which serves as a positive electrode collector, in a manner that forms a coating pattern with a coating width of 240 to 250 mm, a coating length of 125 mm, and a non-coating length of 20 mm, and the solvent is dried and removed using a hot air drying furnace. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.9 g / cm by roller pressing. 3 The positive electrode (P1) consisting of a positive electrode active material layer and a positive electrode current collector was obtained by rolling in a manner of . The unit area weight excluding the positive electrode current collector was 23.8 mg / cm2 The mass of the positive electrode active material excluding the positive electrode current collector is 21.9 mg / cm 2 .

[0665] [Production of negative electrode]

[0666] (a) Artificial graphite powder with a number average particle size of 12.7 μm (density 2.23 g / cm 3 ), acetylene black powder (density 1.95 g / cm 2 ) with a number average particle size of 48 nm as (b) conductive auxiliary agent 3 ), and (c) carboxymethyl cellulose (density 1.60 g / cm 3 ) solution (solid content concentration 1.83% by mass) and diene rubber (glass transition temperature: -5°C, number average particle size when dried: 120 nm, density 1.00 g / cm 3 , dispersion medium: water, solid content concentration 40% by mass) were mixed at a solid content mass ratio of 95.7:0.5:3.8 to obtain a negative electrode mixture.

[0667] Water as a solvent is added to the obtained negative electrode mixture in a manner that the solid content is 45% by mass, and further mixed to prepare a slurry containing the negative electrode mixture. While adjusting the unit area weight of the slurry containing the negative electrode mixture, a three-roll mill transfer coater is used to coat a single side of a copper foil with a thickness of 8μm and a width of 280mm, which serves as a negative electrode collector, in a manner that forms a coating pattern with a coating width of 240 to 250mm, a coating length of 125mm, and a non-coating length of 20mm. The solvent is dried and removed in a hot air drying furnace. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 80°C for 12 hours. Then, the density of the negative electrode active material layer is made into 1.5g / cm by roller pressing. 3 The negative electrode (N1) is formed by rolling in a manner of 1 / 40°C, thereby obtaining a negative electrode (N1) composed of a negative electrode active material layer and a negative electrode current collector. The unit area weight excluding the negative electrode current collector is 11.9 mg / cm 2 The mass of the negative electrode active material excluding the negative electrode current collector is 11.4 mg / cm 2 .

[0668] [Assembly of Coin-Type Non-aqueous Secondary Batteries]

[0669] A polypropylene gasket is installed in a CR2032 type battery case (SUS304 / Al cladding), and in the center, the positive electrode obtained as described above is punched into a disc with a diameter of 15.958mm, with the positive electrode active material layer facing upward. A glass fiber filter paper (Advantec co., ltd., GA-100) is installed on it, which is punched into a disc with a diameter of 16.156mm. After injecting 150μL of non-aqueous electrolyte, the negative electrode obtained as described above is punched into a disc with a diameter of 16.156mm, with the negative electrode active material layer facing downward. After further installing the spacer and spring, the battery cover is inserted and riveted with a riveting machine. The overflowed non-aqueous electrolyte is wiped off with waste cotton yarn. Keep at 25°C for 12 hours to make the laminate and non-aqueous electrolyte fully compatible and obtain a coin-type non-aqueous secondary battery. The coin-type non-aqueous secondary battery has a design capacity of 6 mAh and a rated voltage of 4.2 V.

[0670] [Evaluation of Coin-Type Non-Aqueous Secondary Batteries]

[0671] The coin-type non-aqueous secondary batteries obtained as described above were first charged and the initial charge-discharge capacity was measured according to the following procedure (1-1). Each coin-type non-aqueous secondary battery was then evaluated according to the procedure (1-2) or (1-3). Charging and discharging were performed using a charge-discharge device ACD-M01A (trade name) manufactured by ASKA ELECTRONIC CO., LTD. and a programmable thermostatic bath IN804 (trade name) manufactured by Yamato Scientific Co., Ltd.

[0672] Here, 1C means the current value at which a fully charged battery is expected to be discharged at a constant current and completed in 1 hour. It means the current value at which a fully charged battery is expected to be discharged at a constant current and completed in 1 hour.

[0673] (1-1) Initial Charge and Discharge Processing of Coin-Type Non-aqueous Secondary Batteries

[0674] The coin-type nonaqueous secondary battery was set at an ambient temperature of 25°C and charged at a constant current of 0.1C to 4.2V, then charged at a constant voltage of 4.2V until the current decayed to 0.05C. It was then discharged at a constant current of 0.3C to 3.0V.

[0675] (1-2) Coin-type non-aqueous secondary battery charge and discharge cycle test at 25°C (1.5C)

[0676] A cycle test was performed on the battery that had been subjected to accelerated degradation treatment using the method described in (1-2) above. It should be noted that the ambient temperature of the battery was set to 25°C for the cycle test. First, the battery was charged at a constant current of 1.5C to reach 4.2V, and then charged at a constant voltage of 4.2V until the current decayed to 0.05C. Then, the battery was discharged at a constant current of 1.5C to 3V. This process of charging and discharging once each was considered as one cycle, and 100 cycles of charging and discharging were performed. The discharge capacity of the 100th cycle when the discharge capacity of the first cycle was set to 100% was used as the capacity retention rate.

[0677] Table 8 below shows the constituent components and electrolyte compositions of the non-aqueous secondary batteries of Examples 3 to 4 and Comparative Examples 3 to 5.

[0678] [Table 8]

[0679]

[0680] Table 9 below shows the results of the 25° C. charge-discharge cycle test in Examples 3 and 4 and Comparative Examples 3 and 5.

[0681] [Table 9]

[0682]

[0683] (Analysis of the components of the negative electrode protective film)

[0684] The negative electrode protective film of this example is poorly soluble in non-aqueous electrolytes and therefore has low solubility in organic solvents. Therefore, deuterated water was used to extract the negative electrode protective film. Furthermore, NMR analysis was performed as an analytical method for the compounds represented by the aforementioned general formulas (1) to (3).

[0685] (Extraction of electrode coating)

[0686] For the battery that had undergone the initial charge-discharge process using the method described in (1-1) above, disassemble the battery under an argon atmosphere, place the positive or negative electrode in a screw-threaded glass tube, inject deuterated water into each tube using a syringe, and seal with a cap. After standing for 72 hours to extract the electrode coating, filter the extract through a Pasteur pipette filled with glass wool.

[0687] The concentration of the negative electrode protective film component per 1 g of the active material in this example was calculated by the following measurement method.

[0688] (NMR measurement)

[0689] The obtained extract was added to an NMR tube with a diameter of 3 mm and sealed. Separately, tetrafluorobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved as a standard substance in deuterated chloroform (manufactured by Sigma-Aldrich Co., LLC) containing tetramethylsilane as a chemical shift standard and added to an NMR tube with a diameter of 5 mm. The above-mentioned 3 mm NMR tube was inserted into the NMR tube and the double tube method was used for the measurement. 1 H NMR measurement. In addition, as a quantitative standard substance, a heavy aqueous solution of dimethyl sulfoxide (concentration 0.398 mg / mL) was prepared and the same 1 H NMR determination.

[0690] The measurement apparatus used was a JNM-ECS-400 FT NMR instrument manufactured by JEOL Resonance Co., Ltd. Deuterated chloroform was used as the lock solvent, the accumulation frequency was set to 256 times, and tetramethylsilane (0 ppm) was used as the chemical shift reference. Quantitative calculations involved setting the integral value of the peak attributed to protons of tetrafluorobenzene to 2000, and calculating the integral value per unit concentration equivalent to one proton from the integral value of the signal of dimethyl sulfoxide, a reference substance. This value was used to calculate the concentration in the extract from the integral value of each peak.

[0691] The concentration (Y) of the negative electrode protective film component per 1 g of the active material was calculated by the following mathematical formula.

[0692] (Y) = [concentration in extract D × amount of heavy water C / (mass of electrode excluding current collector A × active material ratio B)] / 1000 [mg / g]

[0693] Table 10 below shows the concentrations of the negative electrode protective film components of the general formula (3) in Example 4 and Comparative Example 5.

[0694] [Table 10]

[0695]

[0696] Table 11 below shows the concentrations of the negative electrode protective film components of the general formula (2) in Example 4 and Comparative Example 5.

[0697] [Table 11]

[0698]

[0699] Table 12 below shows the concentrations of the negative electrode protective film components of the general formula (1) in Example 4 and Comparative Example 5.

[0700] [Table 12]

[0701]

[0702] Table 13 below shows the sum of the negative electrode protective film component concentration (Y1) of the general formula (3) and the negative electrode protective film component concentration (Y2) of the general formula (2) in Example 4 and Comparative Example 5.

[0703] [Table 13]

[0704]

[0705] The results of the 25°C cycle test show that Example 4 has a capacity retention rate of 85% or more, while Comparative Example 5 has a capacity retention rate of 79% or less. In other words, while the compounds of the general formula (3) and (2) are excellent as negative electrode protective films from the perspective of durability, they also function as high-resistance components, and therefore, if their concentrations are too high, battery performance deteriorates.

[0706] <Example (Part 3)>

[0707] Fabrication of coin-type non-aqueous secondary batteries

[0708] [Production of positive electrode]

[0709] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.5 Mn 0.3 Co 0.2 O2), acetylene black powder as (B) a conductive auxiliary agent, and polyvinylidene fluoride (PVDF) as (C) a binder were mixed in a mass ratio of 93.9:3.3:2.8 to obtain a positive electrode mixture.

[0710] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture in a manner that the solid content is 68% by mass, and further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, a three-roll mill transfer coater is used to coat a single side of an aluminum foil with a thickness of 15 μm and a width of 280 mm, which serves as a positive electrode collector, in a manner that forms a coating pattern with a coating width of 240 to 250 mm, a coating length of 125 mm, and a non-coating length of 20 mm, and the solvent is dried and removed using a hot air drying furnace. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.7 g / cm by roller pressing. 3 The positive electrode is formed by rolling in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode current collector. The unit area weight excluding the positive electrode current collector is 9.3 mg / cm 2 The mass of the positive electrode active material excluding the positive electrode current collector is 8.7 mg / cm 2 .

[0711] [Production of negative electrode]

[0712] Graphite powder as (a) negative electrode active material and carboxymethyl cellulose (density 1.60 g / cm 3 ) solution (solid content concentration 1.83% by mass) and diene rubber (glass transition temperature: -5°C, number average particle size when dried: 120 nm, density 1.00 g / cm 3 , dispersion medium: water, solid content concentration 40% by mass, and a solid content mass ratio of 97.4:1.1:1.5 were mixed to obtain a negative electrode mixture.

[0713] Water as a solvent is added to the obtained negative electrode mixture in a manner that the solid content is 45% by mass, and further mixed to prepare a slurry containing the negative electrode mixture. While adjusting the unit area weight of the slurry containing the negative electrode mixture, a three-roll mill transfer coater is used to coat a single side of a copper foil with a thickness of 8μm and a width of 280mm, which serves as a negative electrode collector, in a manner that forms a coating pattern with a coating width of 240 to 250mm, a coating length of 125mm, and a non-coating length of 20mm. The solvent is dried and removed in a hot air drying furnace. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 80°C for 12 hours. Then, the density of the negative electrode active material layer is made into 1.4g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector. The unit area weight excluding the negative electrode current collector is 5.9 mg / cm 2 The mass of the negative electrode active material excluding the negative electrode current collector is 5.7 mg / cm 2 .

[0714] [Assembly of Coin-Type Non-aqueous Secondary Batteries]

[0715] A polypropylene gasket is installed in a CR2032 type battery case (SUS304 / Al cladding), and in the center thereof, the positive electrode obtained as described above is punched out into a disc-shaped material with a diameter of 15.958 mm, with the positive electrode active material layer facing upward. A separator is installed thereon, punched out into a disc-shaped material with a diameter of 16.156 mm, and after injecting 150 μL of non-aqueous electrolyte, the negative electrode obtained as described above is punched out into a disc-shaped material with a diameter of 16.156 mm, with the negative electrode active material layer facing downward. After further installing the spacer and spring, the battery cover is embedded and riveted with a riveting machine. The overflowed non-aqueous electrolyte is wiped off with a waste cotton yarn head. Keep at 25°C for 12 hours to make the laminate and the non-aqueous electrolyte fully compatible to obtain a coin-type non-aqueous secondary battery. The design capacity value of this coin-type non-aqueous secondary battery is 3mAh and the rated voltage value is 4.2V.

[0716] [Evaluation of Coin-Type Non-Aqueous Secondary Batteries]

[0717] The coin-type non-aqueous secondary batteries obtained as described above were first charged and the initial charge-discharge capacity was measured according to the following procedure (1-1). Each coin-type non-aqueous secondary battery was then evaluated according to the procedure (1-2) or (1-3). Charging and discharging were performed using a charge-discharge device ACD-M01A (trade name) manufactured by ASKA ELECTRONIC CO., LTD. and a programmable thermostatic bath IN804 (trade name) manufactured by Yamato Scientific Co., Ltd.

[0718] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[0719] (1-1) Initial Charge and Discharge Processing of Coin-Type Non-aqueous Secondary Batteries

[0720] The coin-type nonaqueous secondary battery was set at an ambient temperature of 25°C and charged at a constant current of 0.1C to 4.2V, then charged at a constant voltage of 4.2V until the current decayed to 0.05C. It was then discharged at a constant current of 0.3C to 3.0V.

[0721] (1-2) Output Test of Coin-Type Non-aqueous Secondary Battery

[0722] For the battery that has been charged and discharged for the first time using the method described in (1-1) above, the ambient temperature of the battery is set to 25°C, and after charging to 4.2V at a constant current of 3mA equivalent to 1C, charging is performed at a constant voltage of 4.2V until the current decays to 0.05C. Then, the battery is discharged to 3.0V at a current value of 1.5mA equivalent to 0.5C. Then, after charging to 4.2V at a constant current of 3mA equivalent to 1C, charging is performed at a constant voltage of 4.2V until the current decays to 0.05C. Then, the current value during constant current discharge is changed to 60mA equivalent to 20C, and the same charge and discharge as above is performed, and the capacity retention rate is calculated by the following mathematical formula.

[0723] Capacity retention rate = (capacity at 20C discharge / capacity at 0.5C discharge) × 100 [%]

[0724] The thickness, porosity, and air permeability of the polyolefin microporous membrane of this example were calculated by the following measurement methods: A three-layer (polypropylene / polyethylene / polypropylene) microporous membrane or a single-layer (polyethylene) microporous membrane was used as the separator.

[0725] (film thickness)

[0726] The thickness was measured at room temperature (23±2°C) using a micro thickness gauge, KBM (trademark), manufactured by Toyo Seiki.

[0727] (Porosity)

[0728] Cut a 10cm x 10cm square sample and calculate its volume (cm 3 ) and mass (g), which are then combined with the film density (g / cm 3 ) is calculated using the following formula.

[0729] Porosity = (volume - mass / membrane density) / volume × 100

[0730] It should be noted that the film density was fixed at 0.95 for calculation.

[0731] (air permeability)

[0732] The density was measured using a Gurley densometer (G-B2 (trademark) manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS P-8117.

[0733] Table 14 below shows the constituent components and electrolyte compositions of the non-aqueous secondary batteries of Examples 5 and 6 and Comparative Examples 6 and 7.

[0734] [Table 14]

[0735]

[0736] In addition, the results of the output tests in Examples 5 and 6 and Comparative Examples 6 and 7 are shown in Table 15 below.

[0737] [Table 15]

[0738]

[0739] <Example (Part 4)>

[0740] Fabrication of coin-type non-aqueous secondary batteries

[0741] [Production of positive electrode]

[0742] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.6 Mn 0.2 Co 0.2 O2), acetylene black powder as (B) a conductive auxiliary agent, and polyvinylidene fluoride (PVDF) as (C) a binder were mixed at a mass ratio of 94:3:3 to obtain a positive electrode mixture.

[0743] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture in a manner that the solid content is 68% by mass, and further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, a three-roll mill transfer coater is used to coat a single side of an aluminum foil with a thickness of 20 μm and a width of 280 mm, which serves as a positive electrode collector, in a manner that forms a coating pattern with a coating width of 240 to 250 mm, a coating length of 125 mm, and a non-coating length of 20 mm, and the solvent is dried and removed in a hot air drying furnace. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.7 g / cm by roller pressing. 3 The positive electrode is formed by rolling in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode current collector. The unit area weight excluding the positive electrode current collector is 10.0 mg / cm 2 The mass of the positive electrode active material excluding the positive electrode current collector is 9.4 mg / cm 2 .

[0744] [Production of negative electrode]

[0745] Graphite powder as (a) a negative electrode active material, acetylene black powder as (b) a conductive additive, and polyvinylidene fluoride (PVDF) as (c) a binder were mixed at a solid content mass ratio of 90.0:3.0:7.0 to obtain a negative electrode mixture.

[0746] Water as a solvent is added to the obtained negative electrode mixture in a manner that the solid content is 45% by mass, and further mixed to prepare a slurry containing the negative electrode mixture. While adjusting the unit area weight of the slurry containing the negative electrode mixture, a three-roll mill transfer coater is used to coat a single side of a copper foil with a thickness of 8μm and a width of 280mm, which serves as a negative electrode collector, in a manner that forms a coating pattern with a coating width of 240 to 250mm, a coating length of 125mm, and a non-coating length of 20mm. The solvent is dried and removed in a hot air drying furnace. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the negative electrode active material layer is made into 1.3g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector. The unit area weight excluding the negative electrode current collector is 5.4 mg / cm 2 The mass of the negative electrode active material excluding the negative electrode current collector is 4.9 mg / cm 2 .

[0747] [Assembly of Coin-Type Non-aqueous Secondary Batteries]

[0748] A polypropylene gasket is installed in a CR2032 type battery case (SUS304 / Al cladding), and in the center, the positive electrode obtained as described above is punched into a disc with a diameter of 15.958mm, with the positive electrode active material layer facing upward. A glass fiber filter paper (Advantec co., ltd., GA-100) is installed on it, which is punched into a disc with a diameter of 16.156mm. After injecting 150μL of non-aqueous electrolyte, the negative electrode obtained as described above is punched into a disc with a diameter of 16.156mm, with the negative electrode active material layer facing downward. After further installing the spacer and spring, the battery cover is inserted and riveted with a riveting machine. The overflowed non-aqueous electrolyte is wiped off with waste cotton yarn. Keep at 25°C for 12 hours to make the laminate and non-aqueous electrolyte fully compatible and obtain a coin-type non-aqueous secondary battery. The coin-type non-aqueous secondary battery has a design capacity of 3 mAh and a rated voltage of 4.2 V.

[0749] [Evaluation of Coin-Type Non-Aqueous Secondary Batteries]

[0750] The coin-type non-aqueous secondary batteries obtained as described above were first charged and the initial charge-discharge capacity was measured according to the following procedure (1-1). Each coin-type non-aqueous secondary battery was then evaluated according to the procedure (1-2) or (1-3). Charging and discharging were performed using a charge-discharge device ACD-M01A (trade name) manufactured by ASKA ELECTRONIC CO., LTD. and a programmable thermostatic bath IN804 (trade name) manufactured by Yamato Scientific Co., Ltd.

[0751] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[0752] (1-1) Initial Charge and Discharge Processing of Coin-Type Non-aqueous Secondary Batteries

[0753] The coin-type nonaqueous secondary battery was set at an ambient temperature of 25°C and charged at a constant current of 0.1C to 4.2V, then charged at a constant voltage of 4.2V until the current decayed to 0.05C. It was then discharged at a constant current of 0.3C to 3.0V.

[0754] (1-2) Coin-type non-aqueous secondary battery charge and discharge cycle test at 25°C (3C)

[0755] A cycle test was performed on a coin-type non-aqueous secondary battery that had been subjected to the first charge and discharge treatment using the method described in (1-1) above. It should be noted that the ambient temperature of the battery was set to 25°C in the cycle test. First, the battery was charged at a constant current of 3C to reach 4.2V, and then charged at a constant voltage of 4.2V until the current decayed to 0.05C. Then, the battery was discharged at a constant current of 3C to 3V. This process of charging and discharging once each was considered as one cycle, and 100 cycles of charging and discharging were performed. The discharge capacity of the 100th cycle when the discharge capacity of the first cycle was set to 100% was used as the capacity retention rate.

[0756] Table 16 below shows the constituent components and electrolyte compositions of each non-aqueous secondary battery of Example 7.

[0757] [Table 16]

[0758]

[0759] In addition, the results of the 25° C. charge-discharge cycle test in Example 7 are shown in Table 17 below.

[0760] [Table 17]

[0761]

[0762] <Example (Part 5)>

[0763] Fabrication of single-layer laminated non-aqueous secondary batteries

[0764] [Production of positive electrode]

[0765] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.6 Mn 0.2 Co 0.2 O2), acetylene black powder as (B) a conductive auxiliary agent, and polyvinylidene fluoride (PVDF) as (C) a binder were mixed in a mass ratio of 93:4:3 to obtain a positive electrode mixture.

[0766] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture, and the mixture is further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, it is applied to one side of an aluminum foil with a thickness of 20 μm, which serves as the positive electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the positive electrode mixture is applied to the aluminum foil, an uncoated area is formed in such a way that a portion of the aluminum foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.9 g / cm by roller pressing. 3The positive electrode is formed by rolling in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode current collector. The unit area weight is 19.0 mg / cm 2 The mass of the positive electrode active material excluding the positive electrode current collector is 17.7 mg / cm 2 .

[0767] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 14 mm x 20 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were then welded to the exposed portion of the aluminum foil. The resulting product was then vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[0768] [Production of negative electrode]

[0769] Graphite powder as (a) negative electrode active material, carboxymethyl cellulose (density 1.60 g / cm 3 ) solution (solid content concentration 1.83% by mass) and diene rubber (glass transition temperature: -5°C, number average particle size when dried: 120 nm, density 1.00 g / cm 3 , dispersion medium: water, solid content concentration 40% by mass) were mixed at a solid content mass ratio of 97.5:1.0:1.5 to obtain a negative electrode mixture.

[0770] N-methyl-2-pyrrolidone as a solvent is added to the obtained negative electrode mixture, and the mixture is further mixed to prepare a slurry containing the negative electrode mixture. While adjusting the unit area weight of the slurry containing the negative electrode mixture, it is applied to one side of a copper foil with a thickness of 8 μm, which serves as the negative electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the negative electrode mixture is applied to the copper foil, an uncoated area is formed in such a way that a portion of the copper foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the negative electrode active material layer is made into 1.45 g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of 10.6 mg / cm2. 2 The mass of the negative electrode active material excluding the negative electrode current collector is 10.3 mg / cm 2 .

[0771] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​15 mm x 21 mm, including the exposed portion of the copper foil. A nickel lead was then welded to the exposed portion of the copper foil for current extraction, and the resulting negative electrode was vacuum-dried at 80°C for 12 hours to obtain a leaded negative electrode.

[0772] [Assembly of a single-layer laminated non-aqueous secondary battery]

[0773] A positive electrode with a lead and a negative electrode with a lead were stacked with the mixture-coated surfaces of each electrode facing each other via a polyethylene microporous membrane separator (21 μm thick) to form a laminated electrode assembly. This laminated electrode assembly was housed in a 90 mm × 80 mm aluminum laminate sheet case and vacuum-dried at 80°C for 5 hours to remove moisture. The aforementioned non-aqueous electrolytes were then injected into the case, and the case was sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery.

[0774] [Evaluation of Single-Layer Laminated Non-Aqueous Secondary Batteries]

[0775] The single-layer laminated nonaqueous secondary batteries obtained as described above were first charged according to the following procedure (1-1), and then evaluated according to the procedure (1-2).

[0776] (1-1) Initial charge and discharge treatment of single-layer laminated non-aqueous secondary batteries

[0777] The single-layer laminated non-aqueous secondary battery was set at an ambient temperature of 25°C and charged at a constant current of 0.025C for 2 hours. After a 3-hour pause, the battery was charged at a constant current of 0.05C to a voltage of 4.2V. The battery was then charged at a constant voltage of 4.2V until the current decayed to 0.02C. The battery was then discharged at a constant current of 0.05C to a voltage of 2.7V.

[0778] (1-2) Cycle test of single-layer laminated non-aqueous secondary battery

[0779] For a single-layer laminated non-aqueous secondary battery that has been subjected to the first charge and discharge treatment using the method described in (1-1) above, the ambient temperature of the battery is set to 50°C, and after charging at a constant current of 0.5C to 4.2V, it is charged at a constant voltage of 4.2V until the current decays to 0.05C. Then, it is discharged at a constant current of 0.5C to 2.7V. This process of charging and discharging once each is considered as one cycle, and 50 cycles of charging and discharging are performed. The discharge capacity of the 50th cycle when the discharge capacity of the first cycle is set to 100% is used as the capacity retention rate.

[0780] The ion conductivity of the electrolyte solution of this example was calculated by the following measurement method.

[0781] (Ionic conductivity measurement)

[0782] The electrolyte was placed in a sealed cell (24 mm diameter x 0.35 mm thick) manufactured by TOYO Corporation, sealed, and inserted into a holder (SH1-Z) and connected. The cell was then placed in a thermostatic bath for AC impedance measurement. Gold electrodes were used. The entire process, from electrolyte collection to filling and sealing the sealed cell, was performed in an Ar glove box.

[0783] Table 18 below shows the constituent components and electrolyte compositions of each non-aqueous secondary battery of Example 8.

[0784] [Table 18]

[0785]

[0786] Table 19 below shows the results of the 50° C. charge-discharge cycle test and ion conductivity in Example 8.

[0787] [Table 19]

[0788]

[0789] <Example (Sixth)>

[0790] Fabrication of single-layer laminated non-aqueous secondary batteries

[0791] [Production of positive electrode]

[0792] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.8 Mn 0.1 Co 0.1 O2), acetylene black powder (density 1.95 g / cm2) with a number average particle size of 48 nm as (B) conductive auxiliary agent 3 ), and (c) polyvinylidene fluoride (PVDF, density 1.75 g / cm 3 ) were mixed in a mass ratio of 92:4:4 to obtain a positive electrode mixture.

[0793] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture, and the mixture is further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, it is applied to one side of an aluminum foil with a thickness of 20 μm, which serves as the positive electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the positive electrode mixture is applied to the aluminum foil, an uncoated area is formed in such a way that a portion of the aluminum foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.8 g / cm by roller pressing. 3The positive electrode is formed by rolling in a manner of 18.2 mg / cm2. 2 The mass of the positive electrode active material excluding the positive electrode current collector is 16.7 mg / cm 2 .

[0794] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 14 mm x 20 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were then welded to the exposed portion of the aluminum foil. The resulting product was then vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[0795] [Production of negative electrode]

[0796] (a) artificial graphite powder as the negative electrode active material, (b) acetylene black powder with a number average particle size of 48 nm (density 1.95 g / cm 3 ), and (c) polyvinylidene fluoride (PVDF, density 1.75 g / cm 3 ) were mixed with a solid content mass ratio of 93:2:5 to obtain a negative electrode mixture.

[0797] N-methyl-2-pyrrolidone as a solvent is added to the obtained negative electrode mixture, and the mixture is further mixed to prepare a slurry containing the negative electrode mixture. While adjusting the unit area weight of the slurry containing the negative electrode mixture, it is applied to one side of a copper foil with a thickness of 10 μm, which serves as the negative electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the negative electrode mixture is applied to the copper foil, an uncoated area is formed in such a way that a portion of the copper foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the negative electrode active material layer is made into 1.5 g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of 11.8 mg / cm2. 2 The mass of the negative electrode active material excluding the negative electrode current collector is 11.0 mg / cm 2 .

[0798] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​15 mm x 21 mm, including the exposed portion of the copper foil. A nickel lead was then welded to the exposed portion of the copper foil for current extraction. The resulting product was then vacuum-dried at 120°C for 12 hours to obtain a negative electrode with leads.

[0799] [Assembly of a single-layer laminated non-aqueous secondary battery]

[0800] A positive electrode with a lead and a negative electrode with a lead were stacked with the mixture-coated surfaces of each electrode facing each other via a polyethylene microporous membrane separator (21 μm thick) to form a laminated electrode body. This laminated electrode body was housed in a 90 mm × 80 mm aluminum laminate sheet case and vacuum-dried at 80°C for 5 hours to remove moisture. The aforementioned non-aqueous electrolytes were then injected into the case, and the case was sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery. This single-layer laminated non-aqueous secondary battery had a design capacity of 7.5 mAh and a rated voltage of 4.2 V.

[0801] [Evaluation of Single-Layer Laminated Non-Aqueous Secondary Batteries]

[0802] The single-layer laminated nonaqueous secondary batteries obtained as described above were first charged according to the following procedure (1-1), and then evaluated according to the procedure (1-2).

[0803] (1-1) Initial charge and discharge treatment of single-layer laminated non-aqueous secondary batteries

[0804] The single-layer laminated non-aqueous secondary battery was set at an ambient temperature of 25°C and charged at a constant current of 0.025C for 2 hours. After a 3-hour pause, the battery was charged at a constant current of 0.05C to a voltage of 4.2V. The battery was then charged at a constant voltage of 4.2V until the current decayed to 0.02C. The battery was then discharged at a constant current equivalent to 0.05C to a voltage of 2.7V.

[0805] (1-2) 35°C Charge-Discharge Cycle Test of Single-Layer Laminated Non-Aqueous Secondary Batteries

[0806] For the single-layer laminated non-aqueous secondary battery that was subjected to the first charge and discharge treatment using the method described in (1-1) above, the ambient temperature of the battery was set to 35°C, and after charging at a constant current of 0.5C to 4.2V, it was charged at a constant voltage of 4.2V until the current decayed to 0.05C. Then, it was discharged at a constant current of 0.5C to 2.7V. This process of charging and discharging once each was considered as one cycle, and 50 cycles of charging and discharging were performed. The discharge capacity of the 50th cycle when the discharge capacity of the first cycle was set to 100% was used as the capacity retention rate.

[0807] Table 20 below shows the constituent components and electrolyte compositions of the non-aqueous secondary batteries of Examples 9 to 11 and Comparative Example 8.

[0808] [Table 20]

[0809]

[0810] In addition, the results of the 35° C. charge-discharge cycle test in Examples 9 to 11 and Comparative Example 8 are shown in Table 21 below.

[0811] [Table 21]

[0812]

[0813] (Analysis of the components of the negative electrode protective film)

[0814] The negative electrode protective coating of this example is poorly soluble in non-aqueous electrolytes and, therefore, has low solubility in organic solvents. Therefore, deuterated water was used to extract the negative electrode protective coating. Furthermore, NMR analysis was performed as a method for analyzing the composition of the negative electrode protective coating.

[0815] (Extraction of electrode coating)

[0816] Single-layer laminated non-aqueous secondary batteries subjected to a 35°C charge-discharge cycle test using the method described in (1-2) above were disassembled under an argon atmosphere. The positive and negative electrodes were placed in separate glass screw-type tubes, each injected with deuterium hydroxide using a syringe, and sealed with a cap. After standing for 72 hours to extract the electrode coating, the extract was filtered through a Pasteur pipette filled with glass wool.

[0817] The concentration of the negative electrode protective film component per 1 g of the active material in this example was calculated by the following measurement method.

[0818] (NMR measurement)

[0819] The obtained extract was added to an NMR tube with a diameter of 3 mm and sealed. Separately, tetrafluorobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved as a standard substance in deuterated chloroform (manufactured by Sigma-Aldrich Co., LLC) containing tetramethylsilane as a chemical shift standard and added to an NMR tube with a diameter of 5 mm. The above-mentioned 3 mm NMR tube was inserted into the NMR tube and the double tube method was used for the measurement. 1 H NMR measurement. In addition, as a quantitative standard substance, a heavy aqueous solution of dimethyl sulfoxide (concentration 0.398 mg / mL) was prepared and the same 1 H NMR determination.

[0820] The measurement apparatus used was a JNM-ECS-400 FT NMR instrument manufactured by JEOL Resonance Co., Ltd. Deuterated chloroform was used as the lock solvent, the accumulation frequency was set to 256 times, and tetramethylsilane (0 ppm) was used as the chemical shift reference. Quantitative calculations involved setting the integral value of the peak attributed to protons of tetrafluorobenzene to 2000, and calculating the integral value per unit concentration equivalent to one proton from the integral value of the signal of dimethyl sulfoxide, a reference substance. This value was used to calculate the concentration in the extract from the integral value of each peak.

[0821] The concentration (Y) of the negative electrode protective film component per 1 g of the active material was calculated by the following mathematical formula.

[0822] (Y) = [concentration in extract D × amount of heavy water C / (mass of electrode excluding current collector A × active material ratio B)] / 1000 [mg / g]

[0823] Table 22 below shows the concentrations of the negative electrode protective film components of the general formula (3) in Example 11 and Comparative Example 8.

[0824] [Table 22]

[0825]

[0826] Table 23 below shows the concentrations of the negative electrode protective film components of the general formula (2) in Example 11 and Comparative Example 8.

[0827] [Table 23]

[0828]

[0829] Table 24 below shows the concentrations of the negative electrode protective film components of the general formula (1) in Example 11 and Comparative Example 8.

[0830] [Table 24]

[0831]

[0832] Table 25 below shows the sum of the negative electrode protective film component concentration (Y1) of the general formula (3) and the negative electrode protective film component concentration (Y2) of the general formula (2) in Example 11 and Comparative Example 8.

[0833] [Table 25]

[0834]

[0835] The results of the 35°C cycle test show that Example 11 has a capacity retention rate of 80% or more, while Comparative Example 8 has a capacity retention rate of 65% or less. In other words, while the compounds of the general formula (3) and (2) are excellent as negative electrode protective films from the perspective of durability, they also function as high-resistance components, and therefore, if their concentrations are too high, battery performance deteriorates.

[0836] <Other embodiments (Part 1)>

[0837] Examples 1-1 to 1-5 and Comparative Examples 1-1 and 1-2 are described below.

[0838] [Example 1-1]

[0839] (1) Preparation of non-aqueous electrolyte

[0840] Under an inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate and vinylene carbonate as a non-aqueous solvent are mixed in a volume ratio of 49:28:21:2. While dissolving in the mixed solution 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) in an amount of 1 L relative to the non-aqueous solvent, 0.2 mass % of succinic anhydride and 0.2 mass % of lithium nitrate as additives are added and mixed to obtain a non-aqueous electrolyte.

[0841] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[0842] (2) Preparation of positive electrode

[0843] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.5 Mn 0.3 Co 0.2 O2), acetylene black powder as a conductive aid, and polyvinylidene fluoride (PVDF) as a binder are mixed in a mass ratio of 100:3.5:3 to obtain a positive electrode mixture. N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture and further mixed to prepare a slurry containing the positive electrode mixture. The slurry containing the positive electrode mixture is made into a unit area weight of about 95.0 g / cm 2 The positive electrode active material layer was coated on one side of a 15 μm thick aluminum foil, which served as the positive electrode current collector, while being adjusted in a manner. When the slurry containing the positive electrode mixture was applied to the aluminum foil, an uncoated area was formed so that a portion of the aluminum foil was exposed. Then, the positive electrode active material layer was rolled to a density of 2.74 g / cm 3 The positive electrode is rolled in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode collector.

[0844] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 30 mm x 50 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were welded to the exposed portion of the aluminum foil, and the product was vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[0845] (3) Preparation of negative electrode

[0846] Graphite as a negative electrode active material, carboxymethyl cellulose as a binder, and styrene-butadiene rubber latex as a binder were mixed in a mass ratio of 100:1.1:1.5 to obtain a negative electrode mixture. An appropriate amount of water was added to the obtained negative electrode mixture and the mixture was thoroughly mixed to prepare a slurry containing the negative electrode mixture. The slurry was prepared to a weight per unit area of ​​about 61.0 g / cm 2 The negative electrode active material layer was coated on one side of a 10 μm thick copper foil at a constant thickness while being adjusted in a manner. When the negative electrode mixture slurry was applied to the copper foil, an uncoated area was formed so that a portion of the copper foil was exposed. Then, the negative electrode active material layer was roll-pressed to a density of 1.35 g / cm 3 The negative electrode is rolled in a manner as shown in FIG. , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector.

[0847] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​32 mm x 52 mm, including the exposed portion of the copper foil. A nickel lead for current extraction was then welded to the exposed portion of the copper foil. The product was then vacuum-dried at 80°C for 12 hours to obtain a negative electrode with leads.

[0848] (4) Fabrication of single-layer laminated batteries

[0849] A positive electrode with a lead and a negative electrode with a lead were stacked with the mixture-coated surfaces of each electrode facing each other, using a polyethylene microporous membrane separator (film thickness 21 μm, air permeability 285 s / 100 cc, porosity 41%) to form a laminated electrode assembly. This laminated electrode assembly was housed in a 90 mm × 80 mm aluminum laminate sheet case and vacuum-dried at 80°C for 5 hours to remove moisture. The electrolyte solution was then injected into the case, and the case was sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (hereinafter referred to simply as a "single-layer laminated battery").

[0850] The single-layer laminated battery has a designed capacity of 23 mAh and a rated voltage of 4.2 V.

[0851] (5) Evaluation of single-layer laminated batteries

[0852] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2) and (5-3). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[0853] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[0854] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[0855] The battery's ambient temperature was set at 25°C. After charging to 4.2V at a constant current of 2.3mA (equivalent to 0.1C), it was charged at a constant voltage of 4.2V until the current decreased to 0.46mA (equivalent to 0.02C). It was then discharged to 3.0V at a constant current of 6.9mA (equivalent to 0.3C).

[0856] (5-2) Output test of single-layer laminated battery

[0857] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C. After charging to 4.2V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.2V for a total of 3 hours. Then, it was discharged to 3.0V at a current value of 23mA equivalent to 1C. Then, the current value during constant current discharge was changed to 230mA equivalent to 10C. The same charge and discharge as above was performed except that the current value was changed to 230mA equivalent to 10C. The capacity retention rate was calculated using the following mathematical formula. Evaluation was performed according to the following criteria.

[0858] Capacity retention rate = (capacity at 10C discharge / capacity at 1C discharge) × 100 [%]

[0859] Evaluation criteria:

[0860] A: When the capacity retention rate is 60% or more

[0861] B: Capacity retention rate is 40% or more and less than 60%

[0862] C: Capacity retention rate is less than 40%

[0863] (5-3) Charge and discharge cycle test of single-layer laminated battery

[0864] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C, and after charging to 4.2V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.2V for a total of 3 hours. Then, it was discharged to 3V at a constant current of 23mA. This process of charging and discharging once each was considered as one cycle, and 100 cycles of charging and discharging were performed. The ratio of the discharge capacity of the 100th cycle to the discharge capacity of the 100th cycle when the discharge capacity of the first cycle was set to 100% was determined as the capacity retention rate and evaluated according to the following criteria.

[0865] Evaluation criteria:

[0866] A: When the capacity retention rate is 90% or more

[0867] B: Capacity retention rate is 80% or more and less than 90%

[0868] C: Capacity retention rate is less than 80%

[0869] [Examples 1-2 to 1-4 and Comparative Example 1-1]

[0870] A non-aqueous electrolyte solution was prepared in the same manner as in Example 1-1 except that the composition of the non-aqueous electrolyte solution was changed as shown in Table 26, and a single-layer laminate battery was produced using the non-aqueous electrolyte solution and evaluated.

[0871] In addition, in Table 26, the abbreviations of each component have the following meanings.

[0872] 〈Non-aqueous solvents〉

[0873] AcN: acetonitrile

[0874] DEC: diethyl carbonate

[0875] EC: Ethylene carbonate

[0876] VC: vinylene carbonate

[0877] <additive>

[0878] SAH: succinic anhydride

[0879] Li nitrate: lithium nitrate

[0880] Nitric acid i Bu: Isobutyl nitrate

[0881] TMA nitrate: trimethylammonium nitrate

[0882] Table 26 shows the compounding of the non-aqueous electrolyte solutions in the above-mentioned Examples and Comparative Examples and the evaluation results of the non-aqueous secondary batteries.

[0883] [Table 26]

[0884]

[0885] [Analysis Example of Negative Electrode]

[0886] (1) Preparation of negative electrode extract

[0887] The nonaqueous secondary battery prepared in Example 1-1 was subjected to the first charge-discharge treatment by the method described in (5-1), and then disassembled under an argon atmosphere to remove the negative electrode.

[0888] Next, the removed negative electrode was cut under an argon atmosphere and an amount equivalent to 130 mg, including the current collector, was placed in a screw-threaded tube. 1 mL of heavy water was added and the tube was sealed with a cap. After standing at room temperature for 72 hours for extraction, the solution was filtered through a Pasteur pipette filled with glass wool to obtain an extract.

[0889] The extract was subjected to the following method 1 H-NMR analysis.

[0890] (2) 1 H-NMR analysis

[0891] The obtained extract was added to an NMR tube with a diameter of 3 mm and sealed.

[0892] In addition, tetrafluorobenzene as a standard substance was dissolved in deuterated chloroform containing tetramethylsilane as a chemical shift standard and added to an NMR tube with a diameter of 5 mm. The above-mentioned NMR tube with a diameter of 3 mm was inserted into the NMR tube and the double tube method was used to perform the 1 H-NMR measurement. In addition, as a quantitative standard substance, a heavy aqueous solution of DMSO (0.398 mg / mL) was prepared and the same 1 H-NMR determination.

[0893] As a result, Li(CO3)CH2CH2(CO3)Li (the compound represented by formula (1)), Li(CO3)CH2CH3 (the compound represented by formula (2)), and Li(CO3)CH3 were detected.

[0894] [Examples 1-5]

[0895] (1) Preparation of non-aqueous electrolyte

[0896] Under an inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate, and vinylene carbonate as a non-aqueous solvent were mixed in a volume ratio of 49:28:21:2. While dissolving in the mixed solution 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) in an amount of 1 L relative to the total amount of the non-aqueous solvent, 5.0% by mass of 4-fluoro-1,3-dioxolane-2-one (FEC) and 0.2% by mass of lithium nitrate were added as additives and mixed to obtain a non-aqueous electrolyte.

[0897] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[0898] (2) Preparation of positive electrode

[0899] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.8 Mn 0.1 Co 0.1 O2), acetylene black powder with a number average particle size of 48 nm (density 1.95 g / cm 3 ), and polyvinylidene fluoride (PVDF, density 1.75 g / cm 3 ) were mixed in a mass ratio of 92:4:4 to obtain a positive electrode mixture.

[0900] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture, and the mixture is further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, it is applied to one side of an aluminum foil with a thickness of 20 μm, which serves as the positive electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the positive electrode mixture is applied to the aluminum foil, an uncoated area is formed in such a way that a portion of the aluminum foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.8 g / cm by roller pressing. 3 The positive electrode is formed by rolling in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode current collector. The unit area weight is 18.1 mg / cm 2 The mass of the positive electrode active material is 16.7 mg / cm 2 .

[0901] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 14 mm x 20 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were then welded to the exposed portion of the aluminum foil. The resulting product was then vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[0902] (3) Preparation of negative electrode

[0903] A negative electrode active material powder of a mixture of Si / SiO2 / graphite (mass ratio 3.19:6.81:90, Si:O=1:1 (molar ratio)) as a negative electrode active material and acetylene black powder (density 1.95 g / cm2) with a number average particle size of 48 nm as a conductive additive were prepared. 3 ), and carboxymethyl cellulose as a binder and styrene-butadiene rubber latex were mixed in a mass ratio of 92:4.0:1.5:2.5 to obtain a negative electrode mixture.

[0904] Water as a solvent is added to the obtained negative electrode mixture, and the mixture is further mixed to prepare a slurry containing the negative electrode mixture. The solid content concentration of the obtained slurry containing the negative electrode mixture is 39.8% by mass. While adjusting the unit area weight of the slurry containing the negative electrode mixture, it is applied to one side of a copper foil with a thickness of 10 μm, which serves as a negative electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the negative electrode mixture is applied to the copper foil, an uncoated area is formed in such a way that a portion of the copper foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the negative electrode active material layer is made into 1.43 g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode collector. The unit area weight is 7.14 mg / cm 2 The mass of the negative electrode active material is 6.57 mg / cm 2 .

[0905] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​15 mm x 21 mm, including the exposed portion of the copper foil. A nickel lead was then welded to the exposed portion of the copper foil for current extraction, and the resulting negative electrode was vacuum-dried at 80°C for 12 hours to obtain a leaded negative electrode.

[0906] (4) Fabrication of single-layer laminated batteries

[0907] The positive electrode with a lead and the negative electrode with a lead are stacked with a polyethylene microporous membrane separator (film thickness 21μm, air permeability 285s / 100cc, porosity 41%) in a manner such that the mixture-coated surfaces of each electrode face each other to form a stacked electrode body. The stacked electrode body is housed in a 50mm×100mm aluminum laminate sheet outer shell and vacuum dried at 80°C for 5 hours to remove moisture. Next, the above-mentioned non-aqueous electrolyte is injected into the outer shell, and the outer shell is sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (single-layer laminated battery). The design capacity of the single-layer laminated battery is 7.5mAh and the rated voltage is 4.2V.

[0908] (5) Evaluation of single-layer laminated batteries

[0909] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2) and (5-3). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[0910] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[0911] The battery's ambient temperature was set at 25°C. After charging for 2 hours at a constant current of 0.188 mA (equivalent to 0.025C), the battery was paused for 3 hours. Next, the battery was charged at a constant current of 0.375 mA (equivalent to 0.05C) to a voltage of 4.2 V. Afterwards, the battery was charged at a constant voltage of 4.2 V until the current decreased to 0.15 mA (equivalent to 0.02C). The battery was then discharged to 2.7 V at a constant current of 0.375 mA (equivalent to 0.05C).

[0912] (5-2) Output test of single-layer laminated battery

[0913] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C. After charging at a constant current of 1.5 mA equivalent to 0.2C to reach 4.2V, it was charged at a constant voltage of 4.2V until the current decayed to 0.15 mA equivalent to 0.02C. It was then discharged to 2.7V at a current value of 1.5 mA equivalent to 0.2C. The current value during constant current discharge was then changed to 30 mA equivalent to 4C. The same charge and discharge as above was performed except that the current value was changed to 30 mA equivalent to 4C. The capacity retention rate was calculated using the following mathematical formula. Evaluation was performed according to the following criteria.

[0914] Capacity retention rate = (capacity at 4C discharge / capacity at 0.2C discharge) × 100 [%]

[0915] Evaluation criteria:

[0916] A: When the capacity retention rate is 60% or more

[0917] B: Capacity retention rate is 40% or more and less than 60%

[0918] C: Capacity retention rate is less than 40%

[0919] (5-3) Charge and discharge cycle test of single-layer laminated battery

[0920] For the battery that has been subjected to the first charge and discharge treatment using the method described in (5-1) above, the ambient temperature of the battery is set to 25°C, and after charging to 4.2V at a constant current of 3.75mA equivalent to 0.5C, it is charged at a constant voltage of 4.2V until the current decays to 0.15mA equivalent to 0.02C. Then, it is discharged to 2.7V at a constant current of 3.75mA equivalent to 0.5C. This process of charging and discharging is performed once each as one cycle, and 100 cycles of charging and discharging are performed. The ratio of the discharge capacity of the 100th cycle to the discharge capacity of the first cycle is determined as the capacity retention rate, and evaluated according to the following criteria.

[0921] Evaluation criteria:

[0922] A: When the capacity retention rate is 90% or more

[0923] B: Capacity retention rate is 80% or more and less than 90%

[0924] C: Capacity retention rate is less than 80%

[0925] [Comparative Example 1-2]

[0926] A non-aqueous electrolyte solution was prepared in the same manner as in Example 1-5 except that the composition of the non-aqueous electrolyte solution was changed as shown in Table 27, and a single-layer laminate battery was produced using the non-aqueous electrolyte solution and evaluated.

[0927] Table 27 shows the compounding of the nonaqueous electrolyte solutions in Example 1-5 and Comparative Example 1-2 and the evaluation results of the nonaqueous secondary batteries.

[0928] In the "(5-3) Charge and discharge cycle test of single-layer laminated battery" of Comparative Example 1-2, the capacity retention rate dropped sharply at the 25th cycle, resulting in a "C" evaluation.

[0929] In addition, in Table 27, the abbreviations of each component have the following meanings.

[0930] 〈Non-aqueous solvents〉

[0931] AcN: acetonitrile

[0932] DEC: diethyl carbonate

[0933] EC: Ethylene carbonate

[0934] VC: vinylene carbonate

[0935] <additive>

[0936] FEC: 4-fluoro-1,3-dioxolane-2-one

[0937] Li nitrate: lithium nitrate

[0938] [Table 27]

[0939]

[0940] <Other Examples (Part 2)>

[0941] Examples 2-1 to 2-5 and Comparative Examples 2-1 and 2-2 are described below.

[0942] [Example 2-1]

[0943] (1) Preparation of non-aqueous electrolyte

[0944] Under inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate and vinylene carbonate as non-aqueous solvent are mixed in a volume ratio of 49:28:21:2. In this mixed solution, lithium hexafluorophosphate (LiPF6) equivalent to 0.3 mole and bis(fluorosulfonyl) lithium imide (LiN(SO2F)2) equivalent to 1.0 mole in an amount of 1L relative to the non-aqueous solvent are dissolved, 0.2% by mass of succinic anhydride and 0.2% by mass of polyethylene glycol methyl ether acrylate (number of repeating units of ethylene glycol unit: about 9) as additives are added and mixed to obtain a non-aqueous electrolyte.

[0945] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[0946] (2) Preparation of positive electrode

[0947] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.5 Mn 0.3 Co 0.2 O2), acetylene black powder as a conductive aid, and polyvinylidene fluoride (PVDF) as a binder are mixed in a mass ratio of 100:3.5:3 to obtain a positive electrode mixture. N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture and further mixed to prepare a slurry containing the positive electrode mixture. The slurry containing the positive electrode mixture is made into a unit area weight of about 95.0 g / cm 2 The positive electrode active material layer was coated on one side of a 15 μm thick aluminum foil, which served as the positive electrode current collector, while being adjusted in a manner. When the slurry containing the positive electrode mixture was applied to the aluminum foil, an uncoated area was formed so that a portion of the aluminum foil was exposed. Then, the positive electrode active material layer was rolled to a density of 2.74 g / cm 3 The positive electrode is rolled in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode collector.

[0948] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 30 mm x 50 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were welded to the exposed portion of the aluminum foil, and the product was vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[0949] (3) Preparation of negative electrode

[0950] Graphite as a negative electrode active material, carboxymethyl cellulose as a binder, and styrene-butadiene rubber latex as a binder were mixed in a mass ratio of 100:1.1:1.5 to obtain a negative electrode mixture. An appropriate amount of water was added to the obtained negative electrode mixture and the mixture was thoroughly mixed to prepare a slurry containing the negative electrode mixture. The slurry was prepared to a weight per unit area of ​​about 61.0 g / cm 2 The negative electrode active material layer was coated on one side of a 10 μm thick copper foil at a constant thickness while being adjusted in a manner. When the negative electrode mixture slurry was applied to the copper foil, an uncoated area was formed so that a portion of the copper foil was exposed. Then, the negative electrode active material layer was roll-pressed to a density of 1.35 g / cm 3 The negative electrode is rolled in a manner as shown in FIG. , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector.

[0951] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​32 mm x 52 mm, including the exposed portion of the copper foil. A nickel lead for current extraction was then welded to the exposed portion of the copper foil. The product was then vacuum-dried at 80°C for 12 hours to obtain a negative electrode with leads.

[0952] (4) Fabrication of single-layer laminated batteries

[0953] A positive electrode with a lead and a negative electrode with a lead were stacked with the mixture-coated surfaces of each electrode facing each other, using a polyethylene microporous membrane separator (film thickness 21 μm, air permeability 285 s / 100 cc, porosity 41%) to form a laminated electrode assembly. This laminated electrode assembly was housed in a 90 mm × 80 mm aluminum laminate sheet case and vacuum-dried at 80°C for 5 hours to remove moisture. The electrolyte solution was then injected into the case, and the case was sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (hereinafter referred to simply as a "single-layer laminated battery").

[0954] The obtained single-layer laminated battery had a designed capacity of 23 mAh and a rated voltage of 4.2 V.

[0955] (5) Evaluation of single-layer laminated batteries

[0956] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2), (5-3), and (5-4). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[0957] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[0958] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[0959] The battery's ambient temperature was set at 25°C. After charging to 4.35V at a constant current of 2.3mA (equivalent to 0.1C), it was charged at a constant voltage of 4.35V until the current decreased to 0.46mA (equivalent to 0.02C). It was then discharged to 3.0V at a constant current of 6.9mA (equivalent to 0.3C).

[0960] (5-2) Output test of single-layer laminated battery

[0961] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C, and after charging to 4.35V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.35V for a total of 3 hours. Then, it was discharged to 3.0V at a current value of 23mA equivalent to 1C. Then, the current value during constant current discharge was changed to 230mA equivalent to 10C, and the same charge and discharge as above was performed. The capacity retention rate was calculated using the following mathematical formula. Evaluation was performed according to the following criteria.

[0962] Capacity retention rate = (capacity at 10C discharge / capacity at 1C discharge) × 100 [%]

[0963] Evaluation criteria:

[0964] A: When the capacity retention rate is 60% or more

[0965] B: Capacity retention rate is 40% or more and less than 60%

[0966] C: Capacity retention rate is less than 40%

[0967] (5-3) Charge-discharge cycle test of single-layer laminated battery at 25°C

[0968] The battery that had been subjected to the initial charge and discharge process by the method described in (5-1) above was subjected to a cycle test. The cycle test was conducted by setting the ambient temperature of the battery to 25° C. and maintaining this temperature until the end of the test.

[0969] The battery was first charged at a constant current of 23 mA (equivalent to 1C) to 4.35 V, then charged at a constant voltage of 4.35 V for a total of 3 hours. It was then discharged at a constant current of 23 mA to 3 V. This process of charging and discharging once each was considered one cycle, and 100 cycles of charge and discharge were performed. The capacity retention rate was calculated as the ratio of the discharge capacity at the 100th cycle to the discharge capacity at the 100th cycle, with the discharge capacity at the 1st cycle being 100%, and was evaluated according to the following criteria.

[0970] Evaluation criteria:

[0971] A: When the capacity retention rate is 90% or more

[0972] B: Capacity retention rate is 80% or more and less than 90%

[0973] C: Capacity retention rate is less than 80%

[0974] (5-4) 50°C Charge-Discharge Cycle Test of Single-Layer Laminated Batteries

[0975] The battery subjected to the initial charge and discharge treatment by the method described in (5-1) above was subjected to a cycle test. The cycle test was started 3 hours after the battery ambient temperature was set to 50°C and continued at 50°C until the end of the test.

[0976] The battery was first charged at a constant current of 23 mA (equivalent to 1C) to 4.2 V, then charged at a constant voltage of 4.2 V for a total of 3 hours. It was then discharged at a constant current of 23 mA to 3 V. This process of charging and discharging once each was considered one cycle, and 100 cycles of charge and discharge were performed. The capacity retention rate was calculated as the ratio of the discharge capacity at the 100th cycle to the discharge capacity at the 100th cycle, with the discharge capacity at the 1st cycle being 100%, and was evaluated according to the following criteria.

[0977] Evaluation criteria:

[0978] A: When the capacity retention rate is 80% or more

[0979] B: Capacity retention rate is 70% or more and less than 80%

[0980] C: Capacity retention rate is less than 70%

[0981] [Examples 2-2 to 2-4 and Comparative Example 2-1]

[0982] A non-aqueous electrolyte solution was prepared in the same manner as in Example 2-1 except that the composition of the non-aqueous electrolyte solution was changed as shown in Tables 28 and 29, and a single-layer laminate battery was produced and evaluated using the non-aqueous electrolyte solution.

[0983] Tables 28 and 29 show the compounding of the nonaqueous electrolyte solutions in the above-mentioned Examples and Comparative Examples and the evaluation results of the nonaqueous secondary batteries.

[0984] In addition, in Tables 28 and 29, the abbreviations of the components have the following meanings.

[0985] 〈Non-aqueous solvents〉

[0986] AcN: acetonitrile

[0987] DEC: diethyl carbonate

[0988] EC: Ethylene carbonate

[0989] VC: vinylene carbonate

[0990] <additive>

[0991] SAH: succinic anhydride

[0992] PEGMEA: polyethylene glycol methyl ether acrylate, number of repeating units of ethylene glycol unit: about 9

[0993] P12BAD: Poly(1,2-butylene adipate)

[0994] BUAC: n-butyl acrylate

[0995] [Table 28]

[0996]

[0997] [Table 29]

[0998]

[0999] [Analysis Example of Negative Electrode]

[1000] (1) Preparation of negative electrode extract

[1001] The nonaqueous secondary battery prepared in Example 2-1 was subjected to the first charge-discharge treatment by the method described in (5-1), and then disassembled under an argon atmosphere to remove the negative electrode.

[1002] Next, the removed negative electrode was cut under an argon atmosphere and an amount equivalent to 130 mg, including the current collector, was placed in a screw-threaded tube. 1 mL of heavy water was added and the tube was sealed with a cap. After standing at room temperature for 72 hours for extraction, the solution was filtered through a Pasteur pipette filled with glass wool to obtain an extract.

[1003] The extract was subjected to the following method 1 H-NMR analysis.

[1004] (2) 1 H-NMR analysis

[1005] The obtained extract was added to an NMR tube with a diameter of 3 mm and sealed.

[1006] In addition, tetrafluorobenzene as a standard substance was dissolved in deuterated chloroform containing tetramethylsilane as a chemical shift standard and added to an NMR tube with a diameter of 5 mm. The above-mentioned NMR tube with a diameter of 3 mm was inserted into the NMR tube and the double tube method was used to perform the 1 H-NMR measurement. In addition, as a quantitative standard substance, a heavy aqueous solution of DMSO (0.398 mg / mL) was prepared and the same 1 H-NMR determination.

[1007] As a result, Li(CO3)CH2CH2(CO3)Li (the compound represented by formula (1)), Li(CO3)CH2CH3 (the compound represented by formula (2)), and Li(CO3)CH3 (the compound represented by formula (3)) were detected.

[1008] [Examples 2-5]

[1009] (1) Preparation of non-aqueous electrolyte

[1010] Under an inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate and vinylene carbonate as a non-aqueous solvent are mixed in a volume ratio of 49:28:21:2. While dissolving the mixed solution in an amount of 1 L relative to the total amount of the non-aqueous solvent, 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) are equivalent, 5.0% by mass of 4-fluoro-1,3-dioxolane-2-one (FEC) and 0.2% by mass of polyethylene glycol methyl ether acrylate (number of repeating units of ethylene glycol units: about 9) are added as additives and mixed to obtain a non-aqueous electrolyte.

[1011] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[1012] (2) Preparation of positive electrode

[1013] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.8 Mn 0.1 Co 0.1O2), acetylene black powder with a number average particle size of 48 nm (density 1.95 g / cm 3 ), and polyvinylidene fluoride (PVDF, density 1.75 g / cm 3 ) were mixed in a mass ratio of 92:4:4 to obtain a positive electrode mixture.

[1014] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture, and the mixture is further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, it is applied to one side of an aluminum foil with a thickness of 20 μm, which serves as the positive electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the positive electrode mixture is applied to the aluminum foil, an uncoated area is formed in such a way that a portion of the aluminum foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.8 g / cm by roller pressing. 3 The positive electrode is formed by rolling in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode current collector. The unit area weight is 18.1 mg / cm 2 The mass of the positive electrode active material is 16.7 mg / cm 2 .

[1015] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 14 mm x 20 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were then welded to the exposed portion of the aluminum foil. The resulting product was then vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[1016] (3) Preparation of negative electrode

[1017] A negative electrode active material powder of a mixture of Si / SiO2 / graphite (mass ratio 3.19:6.81:90, Si:O=1:1 (molar ratio)) as a negative electrode active material and acetylene black powder (density 1.95 g / cm2) with a number average particle size of 48 nm as a conductive additive were prepared. 3 ), and carboxymethyl cellulose as a binder and styrene-butadiene rubber latex were mixed in a mass ratio of 92:4.0:1.5:2.5 to obtain a negative electrode mixture.

[1018] Water as a solvent is added to the obtained negative electrode mixture, and the mixture is further mixed to prepare a slurry containing the negative electrode mixture. The solid content concentration of the obtained slurry containing the negative electrode mixture is 39.8% by mass. While adjusting the unit area weight of the slurry containing the negative electrode mixture, it is applied to one side of a copper foil with a thickness of 10 μm, which serves as a negative electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the negative electrode mixture is applied to the copper foil, an uncoated area is formed in such a way that a portion of the copper foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the negative electrode active material layer is made into 1.43 g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode collector. The unit area weight is 7.14 mg / cm 2 The mass of the negative electrode active material is 6.57 mg / cm 2 .

[1019] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​15 mm x 21 mm, including the exposed portion of the copper foil. A nickel lead was then welded to the exposed portion of the copper foil for current extraction, and the resulting negative electrode was vacuum-dried at 80°C for 12 hours to obtain a leaded negative electrode.

[1020] (4) Fabrication of single-layer laminated batteries

[1021] The positive electrode with a lead and the negative electrode with a lead are stacked with a polyethylene microporous membrane separator (film thickness 21μm, air permeability 285s / 100cc, porosity 41%) in a manner such that the mixture-coated surfaces of each electrode face each other to form a stacked electrode body. The stacked electrode body is housed in a 50mm×100mm aluminum laminate sheet outer shell and vacuum dried at 80°C for 5 hours to remove moisture. Next, the above-mentioned non-aqueous electrolyte is injected into the outer shell, and the outer shell is sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (single-layer laminated battery). The design capacity of the single-layer laminated battery is 7.5mAh and the rated voltage is 4.2V.

[1022] (5) Evaluation of single-layer laminated batteries

[1023] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2) and (5-3). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[1024] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[1025] The battery's ambient temperature was set at 25°C. After charging for 2 hours at a constant current of 0.188 mA (equivalent to 0.025C), the battery was paused for 3 hours. Next, the battery was charged at a constant current of 0.375 mA (equivalent to 0.05C) to a voltage of 4.2 V. Afterwards, the battery was charged at a constant voltage of 4.2 V until the current decreased to 0.15 mA (equivalent to 0.02C). The battery was then discharged to 2.7 V at a constant current of 0.375 mA (equivalent to 0.05C).

[1026] (5-2) Output test of single-layer laminated battery

[1027] For the battery that had undergone the initial charge and discharge process using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C. After charging to 4.2V at a constant current of 1.5mA, equivalent to 0.2C, the battery was then charged at a constant voltage of 4.2V until the current decayed to 0.15mA, equivalent to 0.02C. The battery was then discharged to 2.7V at a current of 1.5mA, equivalent to 0.2C. The same charge and discharge process was then repeated except that the current value during the constant current discharge was changed to 30mA, equivalent to 4C. The capacity retention rate was calculated using the following formula and evaluated according to the following criteria.

[1028] Capacity retention rate = (capacity at 4C discharge / capacity at 0.2C discharge) × 100 [%]

[1029] Evaluation criteria:

[1030] A: When the capacity retention rate is 60% or more

[1031] B: Capacity retention rate is 40% or more and less than 60%

[1032] C: Capacity retention rate is less than 40%

[1033] (5-3) Charge and discharge cycle test of single-layer laminated battery

[1034] For the battery that has been subjected to the first charge and discharge treatment using the method described in (5-1) above, the ambient temperature of the battery is set to 25°C, and after charging to 4.2V at a constant current of 3.75mA equivalent to 0.5C, it is charged at a constant voltage of 4.2V until the current decays to 0.15mA equivalent to 0.02C. Then, it is discharged to 2.7V at a constant current of 3.75mA equivalent to 0.5C. This process of charging and discharging is performed once each as one cycle, and 100 cycles of charging and discharging are performed. The ratio of the discharge capacity of the 100th cycle to the discharge capacity of the first cycle is determined as the capacity retention rate, and evaluated according to the following criteria.

[1035] Evaluation criteria:

[1036] A: When the capacity retention rate is 90% or more

[1037] B: Capacity retention rate is 80% or more and less than 90%

[1038] C: Capacity retention rate is less than 80%

[1039] [Comparative Example 2-2]

[1040] A non-aqueous electrolyte solution was prepared in the same manner as in Example 2-5 except that the composition of the non-aqueous electrolyte solution was changed as shown in Tables 30 and 31, and a single-layer laminate battery was produced and evaluated using the non-aqueous electrolyte solution.

[1041] Tables 30 and 31 show the compounding of the nonaqueous electrolyte solutions in Example 2-5 and Comparative Example 2-2 and the evaluation results of the nonaqueous secondary batteries.

[1042] In the "(5-3) Charge and discharge cycle test of single-layer laminated battery" of Comparative Example 2-2, the capacity retention rate dropped sharply at the 25th cycle, resulting in a "C" evaluation.

[1043] In addition, in Tables 30 and 31, the abbreviations of the components have the following meanings.

[1044] 〈Non-aqueous solvents〉

[1045] AcN: acetonitrile

[1046] DEC: diethyl carbonate

[1047] EC: Ethylene carbonate

[1048] VC: vinylene carbonate

[1049] <additive>

[1050] FEC: 4-fluoro-1,3-dioxolane-2-one

[1051] PEGMEA: polyethylene glycol methyl ether acrylate, number of repeating units of ethylene glycol unit: about 9

[1052] [Table 30]

[1053]

[1054] [Table 31]

[1055]

[1056] <Other Embodiments (Part 3)>

[1057] Examples 3-1 to 3-5 and Comparative Examples 3-1 and 3-2 are described below.

[1058] [Example 3-1]

[1059] (1) Preparation of non-aqueous electrolyte

[1060] Under an inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate and vinylene carbonate as a non-aqueous solvent are mixed in a volume ratio of 49:28:21:2. While dissolving in the mixed solution 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) in an amount of 1 L relative to the non-aqueous solvent, 0.2 mass % of succinic anhydride and 0.2 mass % of sodium cyanoborohydride as additives are added and mixed to obtain a non-aqueous electrolyte.

[1061] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[1062] (2) Preparation of positive electrode

[1063] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.5 Mn 0.3 Co 0.2 O2), acetylene black powder as a conductive aid, and polyvinylidene fluoride (PVDF) as a binder are mixed in a mass ratio of 100:3.5:3 to obtain a positive electrode mixture. N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture and further mixed to prepare a slurry containing the positive electrode mixture. The slurry containing the positive electrode mixture is made into a unit area weight of about 95.0 g / cm 2 The positive electrode active material layer was coated on one side of a 15 μm thick aluminum foil, which served as the positive electrode current collector, while being adjusted in a manner. When the slurry containing the positive electrode mixture was applied to the aluminum foil, an uncoated area was formed so that a portion of the aluminum foil was exposed. Then, the positive electrode active material layer was rolled to a density of 2.74 g / cm 3 The positive electrode is rolled in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode collector.

[1064] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 30 mm x 50 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were welded to the exposed portion of the aluminum foil, and the product was vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[1065] (3) Preparation of negative electrode

[1066] Graphite as a negative electrode active material, carboxymethyl cellulose as a binder, and styrene-butadiene rubber latex as a binder were mixed in a mass ratio of 100:1.1:1.5 to obtain a negative electrode mixture. An appropriate amount of water was added to the obtained negative electrode mixture and the mixture was thoroughly mixed to prepare a slurry containing the negative electrode mixture. The slurry was prepared to a weight per unit area of ​​about 61.0 g / cm 2 The negative electrode active material layer was coated on one side of a 10 μm thick copper foil at a constant thickness while being adjusted in a manner. When the negative electrode mixture slurry was applied to the copper foil, an uncoated area was formed so that a portion of the copper foil was exposed. Then, the negative electrode active material layer was roll-pressed to a density of 1.35 g / cm 3 The negative electrode is rolled in a manner as shown in FIG. , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector.

[1067] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​32 mm x 52 mm, including the exposed portion of the copper foil. A nickel lead for current extraction was then welded to the exposed portion of the copper foil. The product was then vacuum-dried at 80°C for 12 hours to obtain a negative electrode with leads.

[1068] (4) Fabrication of single-layer laminated batteries

[1069] A positive electrode with a lead and a negative electrode with a lead were stacked with the mixture-coated surfaces of each electrode facing each other, using a polyethylene microporous membrane separator (film thickness 21 μm, air permeability 285 s / 100 cc, porosity 41%) to form a laminated electrode assembly. This laminated electrode assembly was housed in a 90 mm × 80 mm aluminum laminate sheet case and vacuum-dried at 80°C for 5 hours to remove moisture. The electrolyte solution was then injected into the case, and the case was sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (hereinafter referred to simply as a "single-layer laminated battery").

[1070] The obtained single-layer laminated battery had a designed capacity of 23 mAh and a rated voltage of 4.2 V.

[1071] (5) Evaluation of single-layer laminated batteries

[1072] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2) and (5-3). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[1073] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[1074] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[1075] The battery's ambient temperature was set at 25°C. After charging to 4.2V at a constant current of 2.3mA (equivalent to 0.1C), it was charged at a constant voltage of 4.2V until the current decreased to 0.46mA (equivalent to 0.02C). It was then discharged to 3.0V at a constant current of 6.9mA (equivalent to 0.3C).

[1076] (5-2) Output test of single-layer laminated battery

[1077] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C. After charging to 4.2V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.2V for a total of 3 hours. Then, it was discharged to 3.0V at a current value of 23mA equivalent to 1C. Then, the current value during constant current discharge was changed to 230mA equivalent to 10C. The same charge and discharge as above was performed except that the current value was changed to 230mA equivalent to 10C. The capacity retention rate was calculated using the following mathematical formula. Evaluation was performed according to the following criteria.

[1078] Capacity retention rate = (capacity at 10C discharge / capacity at 1C discharge) × 100 [%]

[1079] Evaluation criteria:

[1080] A: When the capacity retention rate is 60% or more

[1081] B: Capacity retention rate is 40% or more and less than 60%

[1082] C: Capacity retention rate is less than 40%

[1083] (5-3) Charge and discharge cycle test of single-layer laminated battery

[1084] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C, and after charging to 4.2V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.2V for a total of 3 hours. Then, it was discharged to 3V at a constant current of 23mA. This process of charging and discharging once each was considered as one cycle, and 100 cycles of charging and discharging were performed. The ratio of the discharge capacity of the 100th cycle to the discharge capacity of the 100th cycle when the discharge capacity of the first cycle was set to 100% was determined as the capacity retention rate and evaluated according to the following criteria.

[1085] Evaluation criteria:

[1086] A: When the capacity retention rate is 90% or more

[1087] B: Capacity retention rate is 80% or more and less than 90%

[1088] C: Capacity retention rate is less than 80%

[1089] [Examples 3-2 to 3-4 and Comparative Example 3-1]

[1090] A non-aqueous electrolyte solution was prepared in the same manner as in Example 3-1 except that the composition of the non-aqueous electrolyte solution was changed as shown in Table 32, and a single-layer laminate battery was produced using the non-aqueous electrolyte solution and evaluated.

[1091] In addition, in Table 32, the abbreviations of each component have the following meanings.

[1092] 〈Non-aqueous solvents〉

[1093] AcN: acetonitrile

[1094] DEC: diethyl carbonate

[1095] EC: Ethylene carbonate

[1096] VC: vinylene carbonate

[1097] <additive>

[1098] SAH: succinic anhydride

[1099] CHBNa: sodium cyanoborohydride

[1100] PhSiH: phenylsilane

[1101] TBSH: Tri-n-butyltin hydride

[1102] Table 32 shows the compounding of the non-aqueous electrolyte solutions in the above-mentioned Examples and Comparative Examples and the evaluation results of the non-aqueous secondary batteries.

[1103] [Table 32]

[1104]

[1105] [Analysis Example of Negative Electrode]

[1106] (1) Preparation of negative electrode extract

[1107] The nonaqueous secondary battery prepared in Example 3-1 was subjected to the first charge-discharge treatment by the method described in (5-1), and then disassembled under an argon atmosphere to remove the negative electrode.

[1108] Next, the removed negative electrode was cut under an argon atmosphere and an amount equivalent to 130 mg, including the current collector, was placed in a screw-threaded tube. 1 mL of heavy water was added and the tube was sealed with a cap. After standing at room temperature for 72 hours for extraction, the solution was filtered through a Pasteur pipette filled with glass wool to obtain an extract.

[1109] The extract was subjected to the following method 1 H-NMR analysis.

[1110] (2) 1 H-NMR analysis

[1111] The obtained extract was added to an NMR tube with a diameter of 3 mm and sealed.

[1112] In addition, tetrafluorobenzene as a standard substance was dissolved in deuterated chloroform containing tetramethylsilane as a chemical shift standard and added to an NMR tube with a diameter of 5 mm. The above-mentioned NMR tube with a diameter of 3 mm was inserted into the NMR tube and the double tube method was used to perform the 1 H-NMR measurement. In addition, as a quantitative standard substance, a heavy aqueous solution of DMSO (0.398 mg / mL) was prepared and the same 1 H-NMR determination.

[1113] As a result, Li(CO3)CH2CH2(CO3)Li (the compound represented by formula (1)), Li(CO3)CH2CH3 (the compound represented by formula (2)), and Li(CO3)CH3 (the compound represented by formula (3)) were detected.

[1114] [Examples 3-5]

[1115] (1) Preparation of non-aqueous electrolyte

[1116] Under an inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate, and vinylene carbonate as non-aqueous solvents were mixed in a volume ratio of 49:28:21:2. While dissolving in the mixed solution 0.3 mol of lithium hexafluorophosphate (LiPF6) and 1.0 mol of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2) in an amount of 1 L relative to the total amount of the non-aqueous solvent, 5.0% by mass of 4-fluoro-1,3-dioxolane-2-one (FEC) and 0.2% by mass of sodium cyanoborohydride (CHBNa) were added as additives and mixed to obtain a non-aqueous electrolyte.

[1117] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[1118] (2) Preparation of positive electrode

[1119] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.8 Mn 0.1 Co 0.1 O2), acetylene black powder with a number average particle size of 48 nm (density 1.95 g / cm 3 ), and polyvinylidene fluoride (PVDF, density 1.75 g / cm 3 ) were mixed in a mass ratio of 92:4:4 to obtain a positive electrode mixture.

[1120] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture, and the mixture is further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, it is applied to one side of an aluminum foil with a thickness of 20 μm, which serves as the positive electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the positive electrode mixture is applied to the aluminum foil, an uncoated area is formed in such a way that a portion of the aluminum foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.8 g / cm by roller pressing. 3 The positive electrode is formed by rolling in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode current collector. The unit area weight is 18.1 mg / cm 2 The mass of the positive electrode active material is 16.7 mg / cm 2 .

[1121] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 14 mm x 20 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were then welded to the exposed portion of the aluminum foil. The resulting product was then vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[1122] (3) Preparation of negative electrode

[1123] A negative electrode active material powder of a mixture of Si / SiO2 / graphite (mass ratio 3.19:6.81:90, Si:O=1:1 (molar ratio)) as a negative electrode active material and acetylene black powder (density 1.95 g / cm2) with a number average particle size of 48 nm as a conductive additive were prepared. 3 ), and carboxymethyl cellulose as a binder and styrene-butadiene rubber latex were mixed in a mass ratio of 92:4.0:1.5:2.5 to obtain a negative electrode mixture.

[1124] Water as a solvent is added to the obtained negative electrode mixture, and the mixture is further mixed to prepare a slurry containing the negative electrode mixture. The solid content concentration of the obtained slurry containing the negative electrode mixture is 39.8% by mass. While adjusting the unit area weight of the slurry containing the negative electrode mixture, it is applied to one side of a copper foil with a thickness of 10 μm, which serves as a negative electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the negative electrode mixture is applied to the copper foil, an uncoated area is formed in such a way that a portion of the copper foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the negative electrode active material layer is made into 1.43 g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode collector. The unit area weight is 7.14 mg / cm 2 The mass of the negative electrode active material is 6.57 mg / cm 2 .

[1125] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​15 mm x 21 mm, including the exposed portion of the copper foil. A nickel lead was then welded to the exposed portion of the copper foil for current extraction, and the resulting negative electrode was vacuum-dried at 80°C for 12 hours to obtain a leaded negative electrode.

[1126] (4) Fabrication of single-layer laminated batteries

[1127] The positive electrode with a lead and the negative electrode with a lead are stacked with a polyethylene microporous membrane separator (film thickness 21μm, air permeability 285s / 100cc, porosity 41%) in a manner such that the mixture-coated surfaces of each electrode face each other to form a stacked electrode body. The stacked electrode body is housed in a 50mm×100mm aluminum laminate sheet outer shell and vacuum dried at 80°C for 5 hours to remove moisture. Next, the above-mentioned non-aqueous electrolyte is injected into the outer shell, and the outer shell is sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (single-layer laminated battery). The design capacity of the single-layer laminated battery is 7.5mAh and the rated voltage is 4.2V.

[1128] (5) Evaluation of single-layer laminated batteries

[1129] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2) and (5-3). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[1130] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[1131] The battery's ambient temperature was set at 25°C. After charging for 2 hours at a constant current of 0.188 mA (equivalent to 0.025C), the battery was paused for 3 hours. Next, the battery was charged at a constant current of 0.375 mA (equivalent to 0.05C) to a voltage of 4.2 V. Afterwards, the battery was charged at a constant voltage of 4.2 V until the current decreased to 0.15 mA (equivalent to 0.02C). The battery was then discharged to 2.7 V at a constant current of 0.375 mA (equivalent to 0.05C).

[1132] (5-2) Output test of single-layer laminated battery

[1133] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C. After charging at a constant current of 1.5 mA equivalent to 0.2C to reach 4.2V, it was charged at a constant voltage of 4.2V until the current decayed to 0.15 mA equivalent to 0.02C. It was then discharged to 2.7V at a current value of 1.5 mA equivalent to 0.2C. The current value during constant current discharge was then changed to 30 mA equivalent to 4C. The same charge and discharge as above was performed except that the current value was changed to 30 mA equivalent to 4C. The capacity retention rate was calculated using the following mathematical formula. Evaluation was performed according to the following criteria.

[1134] Capacity retention rate = (capacity at 4C discharge / capacity at 0.2C discharge) × 100 [%]

[1135] Evaluation criteria:

[1136] A: When the capacity retention rate is 60% or more

[1137] B: Capacity retention rate is 40% or more and less than 60%

[1138] C: Capacity retention rate is less than 40%

[1139] (5-3) Charge and discharge cycle test of single-layer laminated battery

[1140] For the battery that has been subjected to the first charge and discharge treatment using the method described in (5-1) above, the ambient temperature of the battery is set to 25°C, and after charging to 4.2V at a constant current of 3.75mA equivalent to 0.5C, it is charged at a constant voltage of 4.2V until the current decays to 0.15mA equivalent to 0.02C. Then, it is discharged to 2.7V at a constant current of 3.75mA equivalent to 0.5C. This process of charging and discharging is performed once each as one cycle, and 100 cycles of charging and discharging are performed. The ratio of the discharge capacity of the 100th cycle to the discharge capacity of the first cycle is determined as the capacity retention rate, and evaluated according to the following criteria.

[1141] Evaluation criteria:

[1142] A: When the capacity retention rate is 90% or more

[1143] B: Capacity retention rate is 80% or more and less than 90%

[1144] C: Capacity retention rate is less than 80%

[1145] [Comparative Example 3-2]

[1146] A non-aqueous electrolyte solution was prepared in the same manner as in Example 3-5 except that the composition of the non-aqueous electrolyte solution was changed as shown in Table 33, and a single-layer laminate battery was produced using the non-aqueous electrolyte solution and evaluated.

[1147] Table 33 shows the compounding of the non-aqueous electrolyte solutions in Example 3-5 and Comparative Example 3-2 and the evaluation results of the non-aqueous secondary batteries.

[1148] In the "(5-3) Charge and discharge cycle test of single-layer laminated battery" of Comparative Example 3-2, the capacity retention rate dropped sharply at the 25th cycle, resulting in a "C" evaluation.

[1149] In addition, in Table 33, the abbreviations of each component have the following meanings.

[1150] 〈Non-aqueous solvents〉

[1151] AcN: acetonitrile

[1152] DEC: diethyl carbonate

[1153] EC: Ethylene carbonate

[1154] VC: vinylene carbonate

[1155] <additive>

[1156] FEC: 4-fluoro-1,3-dioxolane-2-one

[1157] CHBNa: sodium cyanoborohydride

[1158] [Table 33]

[1159]

[1160] <Other Embodiments (Part 4)>

[1161] Examples 4-1 to 4-6 and Comparative Examples 4-1 and 4-2 are described below.

[1162] [Example 4-1]

[1163] (1) Preparation of non-aqueous electrolyte

[1164] Under inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate and vinylene carbonate as non-aqueous solvent are mixed in a volume ratio of 49:28:21:2. In this mixed solution, lithium hexafluorophosphate (LiPF6) equivalent to 0.3 mole and bis(fluorosulfonyl) lithium imide (LiN(SO2F)2) equivalent to 1.0 mole in an amount of 1L relative to the non-aqueous solvent are dissolved, succinic anhydride as an additive and tris(trimethylsilyl) phosphate are added and mixed to obtain a non-aqueous electrolyte.

[1165] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[1166] (2) Preparation of positive electrode

[1167] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.5 Mn 0.3 Co 0.2 O2), acetylene black powder as a conductive aid, and polyvinylidene fluoride (PVDF) as a binder are mixed in a mass ratio of 100:3.5:3 to obtain a positive electrode mixture. N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture and further mixed to prepare a slurry containing the positive electrode mixture. The slurry containing the positive electrode mixture is made into a unit area weight of about 95.0 g / cm 2 The positive electrode active material layer was coated on one side of a 15 μm thick aluminum foil, which served as the positive electrode current collector, while being adjusted in a manner. When the slurry containing the positive electrode mixture was applied to the aluminum foil, an uncoated area was formed so that a portion of the aluminum foil was exposed. Then, the positive electrode active material layer was rolled to a density of 2.74 g / cm 3 The positive electrode is rolled in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode collector.

[1168] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 30 mm x 50 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were welded to the exposed portion of the aluminum foil, and the product was vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[1169] (3) Preparation of negative electrode

[1170] Graphite as a negative electrode active material, carboxymethyl cellulose as a binder, and styrene-butadiene rubber latex as a binder were mixed in a mass ratio of 100:1.1:1.5 to obtain a negative electrode mixture. An appropriate amount of water was added to the obtained negative electrode mixture and the mixture was thoroughly mixed to prepare a slurry containing the negative electrode mixture. The slurry was prepared to a weight per unit area of ​​about 61.0 g / cm2 The negative electrode active material layer was coated on one side of a 10 μm thick copper foil at a constant thickness while being adjusted in a manner. When the negative electrode mixture slurry was applied to the copper foil, an uncoated area was formed so that a portion of the copper foil was exposed. Then, the negative electrode active material layer was roll-pressed to a density of 1.35 g / cm 3 The negative electrode is rolled in a manner as shown in FIG. , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector.

[1171] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​32 mm x 52 mm, including the exposed portion of the copper foil. A nickel lead for current extraction was then welded to the exposed portion of the copper foil. The product was then vacuum-dried at 80°C for 12 hours to obtain a negative electrode with leads.

[1172] (4) Fabrication of single-layer laminated batteries

[1173] A positive electrode with a lead and a negative electrode with a lead were stacked with the mixture-coated surfaces of each electrode facing each other, using a polyethylene microporous membrane separator (film thickness 21 μm, air permeability 285 s / 100 cc, porosity 41%) to form a laminated electrode assembly. This laminated electrode assembly was housed in a 90 mm × 80 mm aluminum laminate sheet case and vacuum-dried at 80°C for 5 hours to remove moisture. The electrolyte solution was then injected into the case, and the case was sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (hereinafter referred to simply as a "single-layer laminated battery").

[1174] The single-layer laminated battery has a designed capacity of 23 mAh and a rated voltage of 4.2 V.

[1175] (5) Evaluation of single-layer laminated batteries

[1176] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2), (5-3), (5-4), and (5-5). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Science Co., Ltd.

[1177] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[1178] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[1179] The battery's ambient temperature was set at 25°C. After charging to 4.35V at a constant current of 2.3mA (equivalent to 0.1C), it was charged at a constant voltage of 4.35V until the current decreased to 0.46mA (equivalent to 0.02C). It was then discharged to 3.0V at a constant current of 6.9mA (equivalent to 0.3C).

[1180] (5-2) Output test of single-layer laminated battery

[1181] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C, and after charging to 4.35V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.35V for a total of 3 hours. Then, it was discharged to 3.0V at a current value of 23mA equivalent to 1C. Then, the current value during constant current discharge was changed to 230mA equivalent to 10C, and the same charge and discharge as above was performed. The capacity retention rate was calculated using the following mathematical formula. Evaluation was performed according to the following criteria.

[1182] Capacity retention rate = (capacity at 10C discharge / capacity at 1C discharge) × 100 [%]

[1183] Evaluation criteria:

[1184] A: When the capacity retention rate is 60% or more

[1185] B: Capacity retention rate is 40% or more and less than 60%

[1186] C: Capacity retention rate is less than 40%

[1187] (5-3) Charge-discharge cycle test of single-layer laminated battery at 25°C

[1188] The battery that had been subjected to the initial charge and discharge process by the method described in (5-1) above was subjected to a cycle test. The cycle test was conducted by setting the ambient temperature of the battery to 25° C. and maintaining this temperature until the end of the test.

[1189] The battery was first charged at a constant current of 23 mA (equivalent to 1C) to 4.35 V, then charged at a constant voltage of 4.35 V for a total of 3 hours. It was then discharged at a constant current of 23 mA to 3 V. This process of charging and discharging once each was considered one cycle, and 100 cycles of charge and discharge were performed. The capacity retention rate was calculated as the ratio of the discharge capacity at the 100th cycle to the discharge capacity at the 100th cycle, with the discharge capacity at the 1st cycle being 100%, and was evaluated according to the following criteria.

[1190] Evaluation criteria:

[1191] A: When the capacity retention rate is 90% or more

[1192] B: Capacity retention rate is 80% or more and less than 90%

[1193] C: Capacity retention rate is less than 80%

[1194] (5-4) Single-layer laminate battery charge and discharge cycle test at -10℃

[1195] The battery that had been subjected to the initial charge and discharge process described in (5-1) was subjected to a cycle test. The cycle test was started 3 hours after the battery ambient temperature was set to -10°C and continued at -10°C until the end of the test.

[1196] The battery was first charged at a constant current of 4.6 mA (equivalent to 0.2C) to 4.35 V. It was then charged at a constant voltage of 4.35 V until the current decayed to 0.46 mA (equivalent to 0.02C). It was then discharged at a constant current of 4.6 mA to 2.5 V. This process of charging and discharging once each constituted one cycle, and 40 cycles of charge and discharge were performed. The capacity retention rate was calculated as the ratio of the discharge capacity at the 40th cycle to the discharge capacity at the first cycle being 100%, and was evaluated according to the following criteria.

[1197] Evaluation criteria:

[1198] A: When the capacity retention rate is 80% or more

[1199] B: Capacity retention rate is 70% or more and less than 80%

[1200] C: Capacity retention rate is less than 70%

[1201] [Examples 4-2 to 4-4 and Comparative Example 4-1]

[1202] A non-aqueous electrolyte solution was prepared in the same manner as in Example 4-1 except that the composition of the non-aqueous electrolyte solution was changed as shown in Table 34, and a single-layer laminated battery was produced using the non-aqueous electrolyte solution and evaluated.

[1203] [Examples 4-5]

[1204] A nonaqueous electrolyte was prepared in the same manner as in Example 4-1 except that 0.2 parts by mass of 1-propylene 1,3-sultone was added relative to 100 parts by mass of the total nonaqueous electrolyte. A single-layer laminated battery was produced and evaluated using the nonaqueous electrolyte.

[1205] Table 34 shows the compounding of the non-aqueous electrolyte solutions in the above-mentioned Examples and Comparative Examples and the evaluation results of the non-aqueous secondary batteries.

[1206] In addition, in Table 34, the abbreviations of each component have the following meanings.

[1207] 〈Non-aqueous solvents〉

[1208] AcN: acetonitrile

[1209] DEC: diethyl carbonate

[1210] EC: Ethylene carbonate

[1211] VC: vinylene carbonate

[1212] <additive>

[1213] SAH: succinic anhydride

[1214] TTSPA: Tris(trimethylsilyl) phosphate

[1215] MTSPI: Mono(trimethylsilyl) phosphite

[1216] TTFSB: tris(2,2,2-trifluoroethylsilyl) borate

[1217] PES: 1-propylene 1,3-sultone

[1218] [Table 34]

[1219]

[1220] [Analysis Example of Negative Electrode]

[1221] (1) Preparation of negative electrode extract

[1222] The nonaqueous secondary battery prepared in Example 4-1 was subjected to the first charge-discharge treatment by the method described in (5-1), and then disassembled under an argon atmosphere to remove the negative electrode.

[1223] Next, the removed negative electrode was cut under an argon atmosphere and an amount equivalent to 130 mg, including the current collector, was placed in a screw-threaded tube. 1 mL of heavy water was added and the tube was sealed with a cap. After standing at room temperature for 72 hours for extraction, the solution was filtered through a Pasteur pipette filled with glass wool to obtain an extract.

[1224] The extract was subjected to the following method 1 H-NMR analysis.

[1225] (2) 1 H-NMR analysis

[1226] The obtained extract was added to an NMR tube with a diameter of 3 mm and sealed.

[1227] In addition, tetrafluorobenzene as a standard substance was dissolved in deuterated chloroform containing tetramethylsilane as a chemical shift standard and added to an NMR tube with a diameter of 5 mm. The above-mentioned NMR tube with a diameter of 3 mm was inserted into the NMR tube and the double tube method was used to perform the 1 H-NMR measurement. In addition, as a quantitative standard substance, a heavy aqueous solution of DMSO (0.398 mg / mL) was prepared and the same 1 H-NMR determination.

[1228] As a result, Li(CO3)CH2CH2(CO3)Li (the compound represented by formula (1)), Li(CO3)CH2CH3 (the compound represented by formula (2)), and Li(CO3)CH3 (the compound represented by formula (3)) were detected.

[1229] [Examples 4-6]

[1230] (1) Preparation of non-aqueous electrolyte

[1231] Under an inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate and vinylene carbonate as a non-aqueous solvent are mixed in a volume ratio of 49:28:21:2. While the mixed solution is dissolved in an amount of 1 L relative to a total of 0.3 moles of lithium hexafluorophosphate (LiPF6) and 1.0 moles of lithium bis(fluorosulfonyl)imide (LiN(SO2F)2), 5.0% by mass of 4-fluoro-1,3-dioxolane-2-one (FEC) and 0.2% by mass of tris(trimethylsilyl) phosphate (TTSPA) as additives are added and mixed to obtain a non-aqueous electrolyte.

[1232] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[1233] (2) Preparation of positive electrode

[1234] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.8 Mn 0.1 Co 0.1 O2), acetylene black powder with a number average particle size of 48 nm (density 1.95 g / cm 3 ), and polyvinylidene fluoride (PVDF, density 1.75 g / cm 3 ) were mixed in a mass ratio of 92:4:4 to obtain a positive electrode mixture.

[1235] N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture, and the mixture is further mixed to prepare a slurry containing the positive electrode mixture. While adjusting the unit area weight of the slurry containing the positive electrode mixture, it is applied to one side of an aluminum foil with a thickness of 20 μm, which serves as the positive electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the positive electrode mixture is applied to the aluminum foil, an uncoated area is formed in such a way that a portion of the aluminum foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the positive electrode active material layer is made into 2.8 g / cm by roller pressing. 3 The positive electrode is formed by rolling in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode current collector. The unit area weight is 18.1 mg / cm 2 The mass of the positive electrode active material is 16.7 mg / cm 2 .

[1236] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 14 mm x 20 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were then welded to the exposed portion of the aluminum foil. The resulting product was then vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[1237] (3) Preparation of negative electrode

[1238] A negative electrode active material powder of a mixture of Si / SiO2 / graphite (mass ratio 3.19:6.81:90, Si:O=1:1 (molar ratio)) as a negative electrode active material and acetylene black powder (density 1.95 g / cm2) with a number average particle size of 48 nm as a conductive additive were prepared. 3 ), carboxymethyl cellulose as a binder and latex of styrene-butadiene rubber as a binder were mixed in a mass ratio of 92:4.0:1.5:2.5 to obtain a negative electrode mixture.

[1239] Water as a solvent is added to the obtained negative electrode mixture, and the mixture is further mixed to prepare a slurry containing the negative electrode mixture. The solid content concentration of the obtained slurry containing the negative electrode mixture is 39.8% by mass. While adjusting the unit area weight of the slurry containing the negative electrode mixture, it is applied to one side of a copper foil with a thickness of 10 μm, which serves as a negative electrode collector, and the solvent is dried and removed using a hot air drying furnace. When the slurry containing the negative electrode mixture is applied to the copper foil, an uncoated area is formed in such a way that a portion of the copper foil is exposed. The two sides of the obtained electrode roll are trimmed and cut, and reduced pressure drying is carried out at 130°C for 8 hours. Then, the density of the negative electrode active material layer is made into 1.43 g / cm by roller pressing. 3 The negative electrode is formed by rolling in a manner of , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode collector. The unit area weight is 7.14 mg / cm 2 The mass of the negative electrode active material is 6.57 mg / cm2 .

[1240] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​15 mm x 21 mm, including the exposed portion of the copper foil. A nickel lead was then welded to the exposed portion of the copper foil for current extraction, and the resulting negative electrode was vacuum-dried at 80°C for 12 hours to obtain a leaded negative electrode.

[1241] (4) Fabrication of single-layer laminated batteries

[1242] The positive electrode with a lead and the negative electrode with a lead are stacked with a polyethylene microporous membrane separator (film thickness 21μm, air permeability 285s / 100cc, porosity 41%) in a manner such that the mixture-coated surfaces of each electrode face each other to form a stacked electrode body. The stacked electrode body is housed in a 50mm×100mm aluminum laminate sheet outer shell and vacuum dried at 80°C for 5 hours to remove moisture. Next, the above-mentioned non-aqueous electrolyte is injected into the outer shell, and the outer shell is sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (single-layer laminated battery). The design capacity of the single-layer laminated battery is 7.5mAh and the rated voltage is 4.2V.

[1243] (5) Evaluation of single-layer laminated batteries

[1244] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2) and (5-3). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[1245] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[1246] The battery's ambient temperature was set at 25°C. After charging for 2 hours at a constant current of 0.188 mA (equivalent to 0.025C), the battery was paused for 3 hours. Next, the battery was charged at a constant current of 0.375 mA (equivalent to 0.05C) to a voltage of 4.2 V. Afterwards, the battery was charged at a constant voltage of 4.2 V until the current decreased to 0.15 mA (equivalent to 0.02C). The battery was then discharged to 2.7 V at a constant current of 0.375 mA (equivalent to 0.05C).

[1247] (5-2) Output test of single-layer laminated battery

[1248] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C. After charging at a constant current of 1.5 mA equivalent to 0.2C to reach 4.2V, it was charged at a constant voltage of 4.2V until the current decayed to 0.15 mA equivalent to 0.02C. It was then discharged to 2.7V at a current value of 1.5 mA equivalent to 0.2C. The current value during constant current discharge was then changed to 30 mA equivalent to 4C. The same charge and discharge as above was performed except that the current value was changed to 30 mA equivalent to 4C. The capacity retention rate was calculated using the following mathematical formula. Evaluation was performed according to the following criteria.

[1249] Capacity retention rate = (capacity at 4C discharge / capacity at 0.2C discharge) × 100 [%]

[1250] Evaluation criteria:

[1251] A: When the capacity retention rate is 60% or more

[1252] B: Capacity retention rate is 40% or more and less than 60%

[1253] C: Capacity retention rate is less than 40%

[1254] (5-3) Charge and discharge cycle test of single-layer laminated battery

[1255] For the battery that has been subjected to the first charge and discharge treatment using the method described in (5-1) above, the ambient temperature of the battery is set to 25°C, and after charging to 4.2V at a constant current of 3.75mA equivalent to 0.5C, it is charged at a constant voltage of 4.2V until the current decays to 0.15mA equivalent to 0.02C. Then, it is discharged to 2.7V at a constant current of 3.75mA equivalent to 0.5C. This process of charging and discharging is performed once each as one cycle, and 100 cycles of charging and discharging are performed. The ratio of the discharge capacity of the 100th cycle to the discharge capacity of the first cycle is determined as the capacity retention rate, and evaluated according to the following criteria.

[1256] Evaluation criteria:

[1257] A: When the capacity retention rate is 90% or more

[1258] B: Capacity retention rate is 80% or more and less than 90%

[1259] C: Capacity retention rate is less than 80%

[1260] [Comparative Example 4-2]

[1261] A non-aqueous electrolyte solution was prepared in the same manner as in Example 4-6 except that the composition of the non-aqueous electrolyte solution was changed as shown in Table 35, and a single-layer laminate battery was produced using the non-aqueous electrolyte solution and evaluated.

[1262] Table 35 shows the compounding of the non-aqueous electrolyte solutions in Example 4-6 and Comparative Example 4-2 and the evaluation results of the non-aqueous secondary batteries.

[1263] In the "(5-3) Charge and discharge cycle test of single-layer laminated battery" of Comparative Example 4-2, the capacity retention rate dropped sharply at the 25th cycle, resulting in a "C" evaluation.

[1264] In addition, in Table 35, the abbreviations of each component have the following meanings.

[1265] 〈Non-aqueous solvents〉

[1266] AcN: acetonitrile

[1267] DEC: diethyl carbonate

[1268] EC: Ethylene carbonate

[1269] VC: vinylene carbonate

[1270] <additive>

[1271] FEC: 4-fluoro-1,3-dioxolane-2-one

[1272] TTSPA: Tris(trimethylsilyl) phosphate

[1273] [Table 35]

[1274]

[1275] <Other Embodiments (Part 5)>

[1276] Examples 5-1 to 5-5 and Comparative Examples 5-1 to 5-2 are described below.

[1277] [Example 5-1]

[1278] (1) Preparation of non-aqueous electrolyte

[1279] Under inert atmosphere, acetonitrile, diethyl carbonate, ethylene carbonate and vinylene carbonate as non-aqueous solvent are mixed in a volume ratio of 49:28:21:2. When the mixed solution is dissolved with respect to the amount of a total of 1L of non-aqueous solvent, 0.3 mole of lithium hexafluorophosphate (LiPF6) and 1.0 mole of bis(fluorosulfonyl) lithium imide (LiN(SO2F)2) are equivalent, 0.2 mass % of succinic anhydride and 0.2 mass % of boric acid tris(2,2,2-trifluoroethyl) ester as additives are added and mixed to obtain a non-aqueous electrolyte.

[1280] The obtained non-aqueous electrolyte solution was visually observed to confirm that all the lithium salt and additives were dissolved.

[1281] (2) Preparation of positive electrode

[1282] The composite oxide of lithium, nickel, manganese and cobalt (LiNi 0.5 Mn 0.3 Co 0.2 O2), acetylene black powder as a conductive aid, and polyvinylidene fluoride (PVDF) as a binder are mixed in a mass ratio of 100:3.5:3 to obtain a positive electrode mixture. N-methyl-2-pyrrolidone as a solvent is added to the obtained positive electrode mixture and further mixed to prepare a slurry containing the positive electrode mixture. The slurry containing the positive electrode mixture is made into a unit area weight of about 95.0 g / cm 2 The positive electrode active material layer was coated on one side of a 15 μm thick aluminum foil, which served as the positive electrode current collector, while being adjusted in a manner. When the slurry containing the positive electrode mixture was applied to the aluminum foil, an uncoated area was formed so that a portion of the aluminum foil was exposed. Then, the positive electrode active material layer was rolled to a density of 2.74 g / cm 3 The positive electrode is rolled in a manner of , thereby obtaining a positive electrode composed of a positive electrode active material layer and a positive electrode collector.

[1283] The positive electrode was then cut so that the area of ​​the positive electrode mixture layer was 30 mm x 50 mm, including the exposed portion of the aluminum foil. Aluminum lead pieces for current extraction were welded to the exposed portion of the aluminum foil, and the product was vacuum-dried at 120°C for 12 hours to obtain a positive electrode with leads.

[1284] (3) Preparation of negative electrode

[1285] Graphite as a negative electrode active material, carboxymethyl cellulose as a binder, and styrene-butadiene rubber latex as a binder were mixed in a mass ratio of 100:1.1:1.5 to obtain a negative electrode mixture. An appropriate amount of water was added to the obtained negative electrode mixture and the mixture was thoroughly mixed to prepare a slurry containing the negative electrode mixture. The slurry was prepared to a weight per unit area of ​​about 61.0 g / cm 2The negative electrode active material layer was coated on one side of a 10 μm thick copper foil at a constant thickness while being adjusted in a manner. When the negative electrode mixture slurry was applied to the copper foil, an uncoated area was formed so that a portion of the copper foil was exposed. Then, the negative electrode active material layer was roll-pressed to a density of 1.35 g / cm 3 The negative electrode is rolled in a manner as shown in FIG. , thereby obtaining a negative electrode composed of a negative electrode active material layer and a negative electrode current collector.

[1286] The negative electrode was then cut so that the negative electrode mixture layer had an area of ​​32 mm x 52 mm, including the exposed portion of the copper foil. A nickel lead for current extraction was then welded to the exposed portion of the copper foil. The product was then vacuum-dried at 80°C for 12 hours to obtain a negative electrode with leads.

[1287] (4) Fabrication of single-layer laminated batteries

[1288] A positive electrode with a lead and a negative electrode with a lead were stacked with the mixture-coated surfaces of each electrode facing each other, using a polyethylene microporous membrane separator (film thickness 21 μm, air permeability 285 s / 100 cc, porosity 41%) to form a laminated electrode assembly. This laminated electrode assembly was housed in a 90 mm × 80 mm aluminum laminate sheet case and vacuum-dried at 80°C for 5 hours to remove moisture. The electrolyte solution was then injected into the case, and the case was sealed to produce a single-layer laminated (pouch-type) non-aqueous secondary battery (hereinafter referred to simply as a "single-layer laminated battery").

[1289] The obtained single-layer laminated battery had a designed capacity of 23 mAh and a rated voltage of 4.2 V.

[1290] (5) Evaluation of single-layer laminated batteries

[1291] The evaluation cells obtained as described above were first charged according to the following procedure (5-1). Each cell was then evaluated according to the procedures (5-2), (5-3), and (5-4). Charging and discharging were performed using the ACD-01 (trade name) charge-discharge device manufactured by ASKA ELECTRONIC CO., LTD. and the PLM-63S (trade name) thermostatic chamber manufactured by Futaba Scientific Co., Ltd.

[1292] Here, 1C refers to a current value at which a fully charged battery is expected to be discharged at a constant current and discharged in 1 hour.

[1293] (5-1) Initial charge and discharge treatment of single-layer laminated batteries

[1294] The battery's ambient temperature was set at 25°C. After charging to 4.2V at a constant current of 2.3mA (equivalent to 0.1C), it was charged at a constant voltage of 4.2V until the current decreased to 0.46mA (equivalent to 0.02C). It was then discharged to 3.0V at a constant current of 6.9mA (equivalent to 0.3C).

[1295] (5-2) Output test of single-layer laminated battery

[1296] For the battery that was first charged and discharged using the method described in (5-1) above, the ambient temperature of the battery was set to 25°C. After charging to 4.2V at a constant current of 23mA equivalent to 1C, it was charged at a constant voltage of 4.2V for a total of 3 hours. Then, it was discharged to 3.0V at a current value of 23mA equivalent to 1C. Then, the current value du...

Claims

1. A non-aqueous secondary battery comprising: A positive electrode containing one or more positive electrode active materials capable of absorbing and releasing lithium ions; a negative electrode containing at least one negative electrode active material selected from the group consisting of a material capable of occluding and releasing lithium ions, and metallic lithium; and Non-aqueous electrolyte, The negative electrode contains at least one compound selected from the group consisting of compounds represented by the following general formula (1), the following general formula (2), and the following general formula (3). The total content of the compounds represented by the general formulae (2) and (3) is 0.01 to 2.5 mg per 1 g of the negative electrode active material. The content of at least one compound selected from the group consisting of compounds represented by the general formulae (1) to (3) is 0.01 to 10 mg per 1 g of the negative electrode active material. The non-aqueous electrolyte solution contains acetonitrile, and the content of the acetonitrile is 5 volume % or more and 66 volume % or less relative to the total amount of the non-aqueous solvent. The negative electrode active material can be at 0.4V vs.Li / Li + Materials that absorb lithium ions at low potentials, The negative electrode active material includes a carbon material.

2. The non-aqueous secondary battery according to claim 1, wherein The content of acetonitrile is 20% by volume or more and 66% by volume or less relative to the total amount of the non-aqueous solvent.

3. The non-aqueous secondary battery according to claim 1 or 2, wherein The content of the acetonitrile is 40% by volume or more and 66% by volume or less relative to the total amount of the non-aqueous solvent.

4. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte contains a fluorine-containing lithium salt.

5. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte contains LiN(SO2C m F 2m+1 )2, wherein m is an integer from 0 to 8.

6. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte contains LiN(SO2F)2 and / or LiN(SO2CF3)2.

7. The non-aqueous secondary battery according to claim 1 or 2, wherein The negative electrode contains PF6 anions.

8. The non-aqueous secondary battery according to claim 1 or 2, wherein The negative electrode contains N(SO2F)2 anions and / or N(SO2CF3)2 anions.

9. The non-aqueous secondary battery according to claim 1 or 2, wherein The negative electrode contains a decomposition product of a cyclic acid anhydride.

10. The non-aqueous secondary battery according to claim 9, wherein The decomposition product of the cyclic acid anhydride contains at least one compound selected from the group consisting of compounds represented by the following general formula (4), the following general formula (5), the following general formula (6), the following general formula (7), the following general formula (8), and the following general formula (9), In the general formula (4), R 6 and R 7 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom, and f is an integer of 1 to 3, In the general formula (5), R 8 and R 9 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom, In the general formula (6), R 10 and R 11 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom, In the general formula (7), R 12 and R 13 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom, In the general formula (8), R 14 and R 15 represents an alkoxy group, an OH group or an OLi group which is optionally substituted by a halogen atom, In the general formula (9), R 16 ~R 19 represents an alkoxy group, an OH group or an OLi group which may be substituted by a halogen atom.

11. The non-aqueous secondary battery according to claim 10, wherein The cyclic acid anhydride contains at least one selected from the group consisting of malonic anhydride, succinic anhydride, glutaric anhydride, maleic anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 2,3-naphthalene dicarboxylic anhydride, and naphthalene-1,4,5,8-tetracarboxylic dianhydride.

12. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte solution contains a non-aqueous solvent, and the non-aqueous solvent contains a cyclic carbonate.

13. The non-aqueous secondary battery according to claim 12, wherein The cyclic carbonate contains vinylene carbonate and / or fluoroethylene carbonate.

14. The non-aqueous secondary battery according to claim 1 or 2, wherein The negative electrode active material contains at least one element capable of forming an alloy with lithium.

15. The non-aqueous secondary battery according to claim 1 or 2, wherein The negative electrode active material contains silicon.

16. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte has an ion conductivity of 15 mS / cm or more at 20°C.

17. The non-aqueous secondary battery according to claim 1 or 2, wherein The separator used in the non-aqueous secondary battery has a thickness of 3 μm or more and 25 μm or less.

18. The non-aqueous secondary battery according to claim 1 or 2, wherein The separator used in the non-aqueous secondary battery has a porosity of 40% or more and 70% or less.

19. The non-aqueous secondary battery according to claim 1 or 2, wherein The air permeability of the separator used in the non-aqueous secondary battery is 100s / 100cm 3 Above 350s / 100cm 3 the following.

20. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte solution contains at least one nitric acid compound selected from the group consisting of nitrates and nitrate esters.

21. The non-aqueous secondary battery according to claim 20, wherein The nitric acid compound is at least one selected from the group consisting of lithium nitrate, sodium nitrate, cesium nitrate, aluminum nitrate, magnesium nitrate, isobutyl nitrate, tetramethylammonium nitrate, and tetraethylammonium nitrate.

22. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte solution contains at least one additive selected from the group consisting of a polymer compound containing a repeating unit represented by any of the following general formula (P1), the following general formula (P2), the following general formula (P3), and the following general formula (P4), and a carboxylic acid ester compound, In the general formula (P1), R1 is a hydrogen atom or an alkyl group, In the general formula (P2), n1 to n3 are the number of repeating units, and each independently represents an integer from 0 to 4. In the general formula (P3), R2 is an alkyl group having 1 to 20 carbon atoms or a fluoroalkyl group having 1 to 20 carbon atoms, In the general formula (P4), R3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

23. The non-aqueous secondary battery according to claim 22, wherein The additive is at least one selected from the group consisting of polyethylene glycol methyl ether acrylate, polypropylene glycol acrylate, polyethylene adipate, poly{di(ethylene glycol) adipate}, poly(1,2-butylene adipate), polyethylene succinate, poly(2,2,2-trifluoroethyl acrylate), poly(L-lactic acid) terminated with acrylate, 2-carboxyethyl acrylate oligomer, ethylene glycol methyl ether acrylate, diethylene glycol ethyl ether acrylate, 2-ethylhexyl acrylate and n-butyl acrylate.

24. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte solution contains at least one additive selected from the group consisting of organometallic hydrides and dicarbonate compounds.

25. The non-aqueous secondary battery according to claim 24, wherein The dicarbonate compound is at least one selected from the group consisting of diallyl dicarbonate, dimethyl dicarbonate, diethyl dicarbonate, and dibenzyl dicarbonate.

26. The non-aqueous secondary battery according to claim 1 or 2, wherein: The non-aqueous electrolyte solution contains a silyl group-containing additive.

27. The non-aqueous secondary battery according to claim 26, wherein The silyl group-containing additive is at least one selected from the group consisting of a compound represented by the following formula (S1) and a polymer compound containing a repeating unit represented by the following formula (S2), In formula (S1), R is independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 5 to 20 carbon atoms; X is O, S, or NH; Z is P, P═O, B, or Si; when Z is P or P═O, n1 is 1, n2 is an integer from 1 to 3, and n2+n3=3; when Z is B, n1 is 1, n2 is an integer from 1 to 3, and n2+n3=3; when Z is Si, n1 is 0, n2 is an integer from 1 to 4, and n2+n3=4, R in formula (S2) has the same meaning as R in formula (S1).

28. The non-aqueous secondary battery according to claim 1 or 2, wherein The non-aqueous electrolyte solution contains an additive containing boron atoms.

29. The non-aqueous secondary battery according to claim 28, wherein The boron atom-containing additive is at least one selected from the group consisting of a compound represented by the following formula (B1) and a compound represented by the following formula (B2), In formula (B1), R 1 are each independently a fluoroalkyl group having 1 to 20 carbon atoms, a fluoroalkenyl group having 2 to 20 carbon atoms, a fluoroalkynyl group having 2 to 20 carbon atoms, a fluoroaryl group having 5 to 20 carbon atoms, or a fluoroacyl group having 2 to 20 carbon atoms, In formula (B2), R 2 Each is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 5 to 20 carbon atoms; n1 is an integer from 1 to 6, n2 is 2×n1; n3 is each independently an integer from 2 to 6, n4 is 2×n3; and n5 is 0 or 1.

30. A non-aqueous electrolyte solution for a non-aqueous secondary battery according to any one of claims 1 to 29, comprising a non-aqueous solvent and a lithium salt. The non-aqueous solvent contains 5% by volume or more and 66% by volume or less of acetonitrile relative to the total amount of the non-aqueous solvent, and The non-aqueous electrolyte further contains at least one nitric acid compound selected from the group consisting of nitrates and nitrate esters.

31. A non-aqueous electrolyte solution for a non-aqueous secondary battery according to any one of claims 1 to 29, comprising a non-aqueous solvent and a lithium salt. The non-aqueous solvent contains 5% by volume or more and 66% by volume or less of acetonitrile relative to the total amount of the non-aqueous solvent, and The non-aqueous electrolyte further comprises at least one additive selected from the group consisting of a polymer compound containing a repeating unit represented by any of the following general formula (P1), the following general formula (P2), the following general formula (P3), and the following general formula (P4), and a carboxylic acid ester compound, In the general formula (P1), R1 is a hydrogen atom or an alkyl group, In the general formula (P2), n1 to n3 are the number of repeating units, and each independently represents an integer from 0 to 4. In the general formula (P3), R2 is an alkyl group having 1 to 20 carbon atoms or a fluoroalkyl group having 1 to 20 carbon atoms, In the general formula (P4), R3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

32. A non-aqueous electrolyte solution for a non-aqueous secondary battery according to any one of claims 1 to 29, comprising a non-aqueous solvent and a lithium salt. The non-aqueous solvent contains 5% by volume or more and 66% by volume or less of acetonitrile relative to the total amount of the non-aqueous solvent, and The non-aqueous electrolyte further contains at least one additive selected from the group consisting of organometallic hydrides and dicarbonate compounds.

33. A non-aqueous electrolyte for a non-aqueous secondary battery according to any one of claims 1 to 29, comprising a non-aqueous solvent and a lithium salt. The non-aqueous solvent contains 5% by volume or more and 66% by volume or less of acetonitrile relative to the total amount of the non-aqueous solvent, and The non-aqueous electrolyte further includes a silyl group-containing additive.

34. A non-aqueous electrolyte for a non-aqueous secondary battery according to any one of claims 1 to 29, comprising a non-aqueous solvent and a lithium salt. The non-aqueous solvent contains 5% by volume or more and 66% by volume or less of acetonitrile relative to the total amount of the non-aqueous solvent, and The non-aqueous electrolyte further includes an additive containing boron atoms.

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