JPWO2020170833A1 - Electrolyte compositions, non-aqueous electrolytes and non-aqueous electrolyte secondary batteries - Google Patents

Abstract

An electrolyte composition containing at least one compound selected from the group consisting of compounds represented by the following general formula (1) and the like, and at least one selected from a solvent and a dispersion medium. [Chemical formula 1] (In the formula, R1 is a hydrocarbon group having 1 to 8 carbon atoms, and R2 to R5 are independently hydrogen atoms, a hydrocarbon group having 1 to 8 carbon atoms, or the like. R6 is a hydrocarbon group having 1 to 8 carbon atoms or the like, and is an integer of n = 1 to 4).

Description

The present invention relates to electrolyte compositions, non-aqueous electrolytes and non-aqueous electrolyte secondary batteries.

Non-aqueous electrolyte secondary batteries such as lithium-ion secondary batteries are small and lightweight, have high energy density, and can be repeatedly charged and discharged. Widely used as a power source. Further, from the viewpoint of environmental problems, electric vehicles using non-aqueous electrolyte secondary batteries and hybrid vehicles using electric power as a part of power are being put into practical use. Therefore, in recent years, further improvement in the performance of the secondary battery is required.

The non-aqueous electrolyte secondary battery is composed of members such as a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. The positive electrode and the negative electrode usually include a current collector and an electrode mixture layer formed on the current collector. The electrode mixture layer is formed by applying, for example, an electrode active material capable of occluding / releasing lithium ions and a slurry composition in which a binder or the like is dispersed in a dispersion medium on a current collector and drying the mixture.

As a method for improving the performance of a secondary battery, a method of using an additive for a non-aqueous electrolyte has been proposed. For example, vinylene carbonate (see, eg, Patent Document 1), methylphenyl carbonate (see, eg, Patent Document 2), (tetrafluorobenzo-1,2-dioxyl) -pentafluorophenyl-borane (eg, Patent Document 3). (See, eg, Patent Document 4), dimethyl malonate (eg, see Patent Document 5), N, N-dimethylsulfoneamide (see, eg, Patent Document 6), vinyl sulfoneamide. (See, for example, Patent Document 7), pentafluorophenylmethyl oxalate (see, for example, Patent Document 8), phenylsilane (see, for example, Patent Document 9) and the like by adding cycle characteristics to the non-aqueous electrolyte. It is said that it is possible to improve battery performance such as charge / discharge capacity and storage characteristics at high temperatures.

Japanese Unexamined Patent Publication No. 2000-1238667 Japanese Unexamined Patent Publication No. 08-293323 Japanese Patent Publication No. 2008-532248 International Publication No. 2006/070546 Japanese Unexamined Patent Publication No. 2002-376673 Japanese Unexamined Patent Publication No. 2004-259697 Japanese Unexamined Patent Publication No. 2013-93242 Japanese Unexamined Patent Publication No. 2007-112737 Japanese Unexamined Patent Publication No. 2008-210769

However, although many electrolyte additives have been developed to improve battery performance, the cycle characteristics (maintenance performance of battery capacity after repeated charging and discharging) are not sufficient, and only the improvement of cycle characteristics is sufficient. There is also a need for excellent rate characteristics that do not cause a decrease in capacity even when charged and discharged in a short time, and it is necessary to improve cycle characteristics and rate characteristics at the same time.

Therefore, an object of the present invention is to provide an electrolyte composition capable of improving the cycle characteristics and rate characteristics of a non-aqueous electrolyte secondary battery.

That is, the present invention is for an electrolyte containing at least one compound selected from the group consisting of the compounds represented by the following general formulas (1) to (4) and at least one selected from a solvent and a dispersion medium. It is a composition.

(In the formula, R ¹ is a hydrocarbon group having 1 to 8 carbon atoms, and R ^{2 to} R ⁵ are independently a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, and 1 carbon atom. An alkoxy group of ~ 6 or the following formula (1-a), where R ⁶ is a nitro group, a sulfonic acid group, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and the following formula. (1-b) or the following formula (1-c), when R ⁶ is a hydrocarbon group having 1 to 8 carbon atoms, n = an integer of 1 to 4, and R ⁶ is nitro. A group, a sulfonic acid group, an alkoxy group having 1 to 6 carbon atoms, or n = 1 when the formula (1-b) ^{is described below, and when R 6} is the formula (1-c) below. , N = 2.)

(* In the formula indicates the connection position.)

(In the formula, R ⁷ is the following formula (1-d) or the following formula (1-e).)

(In the formula, R ^{8 to} R ¹⁶ each independently have a hydrogen atom, an unsubstituted hydrocarbon group having 1 to 8 carbon atoms, and a part of the hydrogen atom substituted with a fluorine atom to have 1 to 8 carbon atoms. Hydrocarbon group, unsubstituted alkoxy group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms in which a part of hydrogen atom is substituted with a fluorine atom, and unsubstituted carbon atom number 1 to 6 A thioalkoxy group, a thioalkoxy group having 1 to 6 carbon atoms in which a part of hydrogen atoms is replaced with a fluorine atom, a sulfonyl group having a hydrocarbon group having 1 to 8 carbon atoms, or a carbide having 1 to 8 carbon atoms. It is an acyl group having a hydrogen group, and * indicates the bond position.)

(In the formula, m = 1 or 2, and when m = 1, R ^{17 to} R ¹⁹ are each independently a hydrocarbon group having 1 to 8 carbon atoms, and R ¹⁸ and R ¹⁹ are linked. In the case of m = 2, R ¹⁷ and R ¹⁹ are each independently a hydrocarbon group having 1 to 8 carbon atoms, and R ¹⁸ is a single bond.)

(In the formula, R ²⁰ and R ²¹ are each independently a hydrocarbon group having 1 to 8 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and R ^{22 to} R ³¹ are independent hydrogen groups, respectively. Atom, hydrocarbon group with 1 to 8 carbon atoms, alkoxy group with 1 to 6 carbon atoms, halogen atom or nitro group).

According to the present invention, it is possible to provide an electrolyte composition capable of improving the cycle characteristics and rate characteristics of a non-aqueous electrolyte secondary battery.

It is a vertical sectional view schematically showing an example of the structure of the coin-type battery of the non-aqueous electrolyte secondary battery of this invention. It is a schematic diagram which shows the basic structure of the cylindrical battery of the non-aqueous electrolyte secondary battery of this invention. It is a perspective view which shows the internal structure of the cylindrical battery of the non-aqueous electrolyte secondary battery of this invention as a cross section.

<Composition for electrolyte>
The composition for an electrolyte of the present invention contains at least one compound selected from the group consisting of compounds represented by the following general formulas (1) to (4), and at least one selected from a solvent and a dispersion medium. do.

(In the formula, R ¹ is a hydrocarbon group having 1 to 8 carbon atoms, and R ^{2 to} R ⁵ are independently a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, and 1 carbon atom. An alkoxy group of ~ 6 or the following formula (1-a), where R ⁶ is a nitro group, a sulfonic acid group, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and the following formula. (1-b) or the following formula (1-c), when R ⁶ is a hydrocarbon group having 1 to 8 carbon atoms, n = an integer of 1 to 4, and R ⁶ is nitro. A group, a sulfonic acid group, an alkoxy group having 1 to 6 carbon atoms, or n = 1 when the formula (1-b) ^{is described below, and when R 6} is the formula (1-c) below. , N = 2.)

(* In the formula indicates the connection position.)

(In the formula, R ⁷ is the following formula (1-d) or the following formula (1-e).)

(In the formula, R ^{8 to} R ¹⁶ each independently have a hydrogen atom, an unsubstituted hydrocarbon group having 1 to 8 carbon atoms, and a part of the hydrogen atom substituted with a fluorine atom to have 1 to 8 carbon atoms. Hydrocarbon group, unsubstituted alkoxy group with 1 to 6 carbon atoms, alkoxy group with 1 to 6 carbon atoms in which a part of hydrogen atom is replaced with fluorine atom, and unsubstituted carbon atom number 1 to 6 Thioalkoxy group, thioalkoxy group with 1 to 6 carbon atoms in which a part of hydrogen atom is replaced with fluorine atom, sulfonyl group with hydrocarbon group with 1 to 8 carbon atoms, or carbonization with 1 to 8 carbon atoms It is an acyl group having a hydrogen group, and * indicates the bond position.)

(In the formula, m = 1 or 2, and when m = 1, R ^{17 to} R ¹⁹ are each independently a hydrocarbon group having 1 to 8 carbon atoms, and R ¹⁸ and R ¹⁹ are linked. In the case of m = 2, R ¹⁷ and R ¹⁹ are each independently a hydrocarbon group having 1 to 8 carbon atoms, and R ¹⁸ is a single bond.)

(In the formula, R ²⁰ and R ²¹ are each independently a hydrocarbon group having 1 to 8 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and R ^{22 to} R ³¹ are independent hydrogen groups, respectively. Atom, hydrocarbon group with 1 to 8 carbon atoms, alkoxy group with 1 to 6 carbon atoms, halogen atom or nitro group).

Examples of the hydrocarbon group having 1 to 8 carbon atoms representing ^{R 1 to} R ⁵ of the compound represented by the general formula (1) include an aliphatic hydrocarbon group and an aromatic hydrocarbon group.
Specifically, methyl group, ethyl group, propyl group, i-propyl group, butyl group, 2-butyl group, i-butyl group, t-butyl group, pentyl group, 2-pentyl group, 3-pentyl group, Saturated aliphatic groups such as i-pentyl group, hexyl group, 2-hexyl group, 3-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group and norbornan group. Unsaturated aliphatic hydrocarbon groups such as hydrocarbon group, vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, cyclopentenyl group, cyclohexenyl group, cyclooctenyl group, norbornene group, phenyl group, methylphenyl group, ethyl Examples thereof include aromatic hydrocarbon groups such as phenyl group, phenylmethyl group, phenylethyl group and benzyl group. The saturated aliphatic hydrocarbon group and the unsaturated aliphatic hydrocarbon group may have a linear structure, a branched structure, or a cyclic structure.

Examples of the alkoxy group having 1 to 6 carbon atoms representing R ^{2 to} R ⁵ include a methoxy group, an ethoxy group, a propoxy group, an i-propoxy group, a butoxy group, a pentyroxy group, a hexyloxy group, a cyclohexyloxy group and the like. Be done.

Examples of the hydrocarbon group having 1 to 8 carbon atoms representing R ⁶ include the same hydrocarbon groups having 1 to 8 carbon atoms in ^{R 1 to} R ^5.

Examples of the alkoxy group having 1 to 6 carbon atoms representing R ⁶ include the same alkoxy groups having 1 to 6 carbon atoms in ^{R 2 to} R ^5.

As a specific example of the compound represented by the general formula (1), R ¹ is a hydrocarbon group having 1 to 8 carbon atoms, and R ^{2 to} R ⁵ are independently hydrogen atoms and 1 carbon atom. ~ 8 Hydrocarbon groups, alkoxy groups having 1 to 6 carbon atoms or the above formula (1-a), where R ⁶ is a nitro group, a sulfonic acid group, a hydrocarbon group having 1 to 8 carbon atoms or carbon. When it is an alkoxy group having 1 to 6 atoms and n = 1, for example, the following compounds represented by 1-1 to 1-61 can be mentioned, but the present invention is not limited thereto.

As a specific example of the compound represented by the general formula (1), R ¹ is a hydrocarbon group having 1 to 8 carbon atoms, and R ^{2 to} R ⁵ are hydrogen atoms or carbon atoms having 1 to 8 carbon atoms. When it is a hydrogen group and R ⁶ is the above formula (1-b) or the above formula (1-c) and n = 1 or 2, for example, the compound represented by the following 1-62 to 1-70 is However, it is not limited to these.

As a specific example of the compound represented by the general formula (1), R ¹ is a hydrocarbon group having 1 to 8 carbon atoms, and R ^{2 to} R ⁵ are hydrogen atoms or carbon atoms having 1 to 8 carbon atoms. When it is a hydrogen group, R ⁶ is a hydrocarbon group having 1 to 8 carbon atoms, and n = an integer of 2 to 4, for example, the following compounds represented by 1-71 to 1-78 can be mentioned. , Not limited to these.

Since it is excellent in cycle characteristics and rate characteristics, R ¹ of the compound represented by the general formula (1) is preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, a phenyl group or a benzyl group. It is more preferably a methyl group, an allyl group, a t-butyl group or a benzyl group, and R ^{2 to} R ⁵ include a hydrogen atom, a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, or the above formula (1-). a) is preferable, and R ⁶ is a nitro group, a sulfonic acid group, a saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and the above formula (1-b) or the above formula (1-c). It is preferable to have. Among them, 1-1, 1-2, 1-16, 1-17, 1-37, 1-39, 1-40, 1-41, 1-50, 1-51, 1-52, 1-54 , 1-56, 1-62, 1-64, 1-67, 1-70, 1-72, 1-75, 1-77 and 1-78 are more preferable. The compounds represented by 1-37, 1-39, 1-40, 1-52, 1-62, 1-70, 1-72, 1-75, 1-77 and 1-78 are more preferable.

As a method for producing a compound represented by the general formula (1), for example, a carbonate compound such as methyl 4-methylphenyl carbonate is a methyl chloroform with respect to a phenol compound such as 4-methylphenol in the presence of an organic base. It can be efficiently obtained by reacting with chloroformates such as mate.

The compound represented by the general formula (2) has an unsubstituted number of carbon atoms 1 to 8 representing ^{R 8 to} R ¹⁶ in the above formula (1-d) representing ^{R 7 and the above formula (1-e).} Specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, an i-propyl group, a butyl group, a 2-butyl group, an i-butyl group, a t-butyl group, a pentyl group, and a 2-pentyl group. , 3-pentyl group, i-pentyl group, hexyl group, 2-hexyl group, 3-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, norbornan Saturated aliphatic hydrocarbon group such as group, vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, cyclopentenyl group, unsaturated aliphatic hydrocarbon group such as cyclohexenyl group, aromatic hydrocarbon such as phenyl group The group is mentioned. In R ^{8 to} R ¹⁶ , some of the hydrogen atoms in these hydrocarbon groups may be substituted with fluorine atoms. The saturated aliphatic hydrocarbon group and the unsaturated aliphatic hydrocarbon group may have a linear structure, a branched structure, or a cyclic structure.

The compound represented by the general formula (2) has an unsubstituted carbon atom number 1 to 6 representing ^{R 8 to} R ¹⁶ in the above formula (1-d) representing ^{R 7 and the above formula (1-e).} Examples of the alkoxy group include the same alkoxy groups having 1 to 6 carbon atoms representing ^{R 2 to} R ⁵ of the compound represented by the general formula (1). In R ^{8 to} R ¹⁶ , a part of the hydrogen atom in the alkoxy group may be substituted with a fluorine atom.

The compound represented by the general formula (2) has an unsubstituted carbon atom number 1 to 6 representing ^{R 8 to} R ¹⁶ in the above formula (1-d) representing ^{R 7 and the above formula (1-e).} Examples of the thioalkoxy group include a group in which an alkoxy group having 1 to 6 carbon atoms representing ^{R 1 to} R ⁵ of the compound represented by the general formula (1) is bonded with a sulfur atom instead of an oxygen atom. In R ^{8 to} R ¹⁶ , a part of the hydrogen atom in the thioalkoxy group may be substituted with a fluorine atom.

The hydrocarbon group having 1 to 8 carbon atoms contained in the sulfonyl group or the acyl group includes a hydrocarbon group having 1 to 8 carbon atoms representing ^{R 1 to} R ^{5 of the compound represented by the general formula (1).} The same can be mentioned.

Specific examples of the compound represented by the general formula (2) include, but are not limited to, the compounds represented by the following 2-1 to 2-24.

Since it is excellent in cycle characteristics and rate characteristics, ^{R 8} , R ⁹ , R ¹¹ and R ^{12 in the} above formula (1-d) representing ^{R 7} of the compound represented by the general formula (2) are hydrogen atoms. R ¹⁰ preferably has a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a thioalkoxy group having 1 to 4 carbon atoms, and a fluoromethoxy group. , A fluorothiomethoxy group, a sulfonyl group having an aliphatic hydrocarbon group having 1 to 4 carbon atoms, or an acyl group having an aliphatic hydrocarbon group having 1 to 4 carbon atoms, preferably a methoxy group or a thiomethoxy group. , Trifluoromethoxy group or methylsulfonyl group is more preferable. Since it is excellent in cycle characteristics and rate characteristics, it is preferable that ^{R 14 to} R ¹⁶ in the above formula (1-e) representing ^{R 7 of the compound represented by the general formula (2) are hydrogen atoms.} Among them, the compounds represented by the above 2-1 and 2-2, 2-6, 2-7, 2-10, 2-11, 2-12, 2-14, 2-18 and 2-22 are more preferable. , 2-1 and 2-10, 2-11, 2-12, 2-14 and 2-22 are more preferred.

As a method for producing a compound represented by the general formula (2), for example, an oxalic acid ester compound such as diphenyl oxalate is prepared by reacting an alcohol compound such as phenol with oxalyl chloride in the presence of an organic base. It can be obtained efficiently.

As the hydrocarbon group having 1 to 8 carbon atoms representing ^{R 17 to} R ¹⁹ of the compound represented by the general formula (3) ^{, R 1 to} R ⁵ of the compound represented by the general formula (1) are used. The same as the hydrocarbon group having 1 to 8 carbon atoms represented can be mentioned.

Specific examples of the compound represented by the general formula (3) include, but are not limited to, the compounds represented by the following 3-1 to 3-14.

Since the compound represented by the general formula (3) is excellent in cycle characteristics and rate characteristics, ^{it is preferable that R 17} is an aliphatic hydrocarbon having 1 to 3 carbon atoms when m = 1. It is more preferably a methyl group or an ethyl group, and R ¹⁸ and R ¹⁹ are aliphatic hydrocarbon groups having 1 to 3 carbon atoms or cyclohexyl groups in which ^{R 18} and R ^{19 form a ring.} When m = 2, R ¹⁷ and R ¹⁹ are preferably aliphatic hydrocarbon groups having 1 to 3 carbon atoms. Among them, the compounds represented by the above 3-1, 3-6, 3-9, 3-10 and 3-12 are more preferable, and the compounds represented by the above 3-1, 3-9 and 3-12 are further preferable. preferable.

As a method for producing a compound represented by the general formula (3), for example, a sulfonic acid oxime compound such as propanone methanesulfonic acid oxime has an acetoxime or the like as opposed to a sulfonyl chloride such as methanesulfonyl chloride in the presence of an organic base. It can be efficiently obtained by reacting the oxime compound of.

As the hydrocarbon group having 1 to 8 carbon atoms representing ^{R 20 to} R ³¹ of the compound represented by the general formula (4) ^{, R 1 to} R ⁵ of the compound represented by the general formula (1) are used. Examples thereof include the same hydrocarbon groups having 1 to 8 carbon atoms. The alkoxy group having 1 to 6 carbon atoms representing R ^{20 to} R ³¹ is the same as the alkoxy group having 1 to 6 carbon atoms representing ^{R 2 to} R ⁵ of the compound represented by the general formula (1). Can be mentioned.

Specific examples of the compound represented by the general formula (4) include, but are not limited to, the compounds represented by the following 4-1 to 4-24.

Since the compound represented by the general formula (4) is excellent in cycle characteristics and rate characteristics, R ²⁰ and R ²¹ are preferably aliphatic hydrocarbon groups having 1 to 4 carbon atoms, and are preferably methyl groups. R ²² , R ²³ , R ^{25 to} R ²⁸ , R ³⁰ and R ³¹ are more preferably hydrogen atoms or fluorine atoms, more preferably hydrogen atoms, and R ²⁴ and R. ²⁹ is preferably a hydrogen atom, a fluorine atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms, an alkoxy group or a nitro group having 1 to 3 carbon atoms, and preferably a fluorine atom or a nitro group. More preferred. Among them, the compounds represented by the above 4-1 and 4-3, 4-9, 4-13, 4-16 and 4-19 are more preferable, and the compounds represented by the above 4-3, 4-13 and 4-16 are more preferable. Compounds are more preferred.

As a method for producing the compound represented by the general formula (4), for example, a silane compound such as bis (4-fluorophenoxy) dimethylsilane is 4 with respect to a chlorosilane compound such as dimethyldichlorosilane in the presence of an organic base. -It can be efficiently obtained by reacting a phenol compound such as fluorophenol.

The form of the composition for an electrolyte of the present invention is not particularly limited, and the polymer compound is dissolved in an organic solvent as a liquid form, a solvent or a dispersion medium obtained by using an organic solvent as a solvent, and gelled. Examples thereof include a polymer gel form obtained by using a molecular gel, a polymer form obtained by using a polymer as a dispersion medium without using a solvent, and the like.

As the solvent used in the composition for an electrolyte of the present invention, an organic solvent usually used for a non-aqueous electrolyte of a non-aqueous electrolyte secondary battery can be used. Specific examples of the organic solvent include, for example, a saturated cyclic carbonate compound, a saturated cyclic ester compound, a sulfoxide compound, a sulfone compound, an amide compound, a saturated chain carbonate compound, a chain ether compound, a cyclic ether compound, a saturated chain ester compound and the like. Can be mentioned. These organic solvents may be used alone or in combination of two or more. Among these organic solvents, a saturated cyclic carbonate compound, a saturated cyclic ester compound, a sulfoxide compound, a sulfone compound and an amide compound are preferable in that they have a high relative permittivity and play a role in increasing the dielectric constant of the composition for an electrolyte. Saturated cyclic carbonate compounds are more preferred.

Examples of the saturated cyclic carbonate compound include ethylene carbonate, 1,2-propylene carbonate, 1,3-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, 1,1-dimethylethylene carbonate and the like. Be done.
Examples of the saturated cyclic ester compound include γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-hexanolactone, and δ-octanolactone.
Examples of the sulfoxide compound include dimethyl sulfoxide, diethyl sulfoxide, dipropyl sulfoxide, diphenyl sulfoxide, thiophene and the like.
Examples of the sulfone compound include dimethyl sulfone, diethyl sulfone, dipropyl sulfone, diphenyl sulfone, sulfolane (also referred to as tetramethylene sulfone), 3-methyl sulfolane, 3,4-dimethyl sulfolane, 3,4-diphenylmethyl sulfolane, and the like. Examples thereof include sulforene, 3-methylsulfolen, 3-ethylsulfolen, 3-bromomethylsulfolen and the like. Among these, sulfolane and tetramethylsulfolane are preferable.
Examples of the amide compound include N-methylpyrrolidone, dimethylformamide, dimethylacetamide and the like.

Among organic solvents, saturated chain carbonates can reduce the viscosity of the electrolyte composition, increase the mobility of electrolyte ions, and improve battery characteristics such as output density. Compounds, chain ether compounds, cyclic ether compounds and saturated chain ester compounds are preferred. Further, a saturated chain carbonate compound is particularly preferable because it has a low viscosity and can improve the performance of the composition for an electrolyte at a low temperature.

Examples of the saturated chain carbonate compound include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl butyl carbonate, methyl-t-butyl carbonate, diisopropyl carbonate, t-butyl propyl carbonate and the like.
Examples of the chain ether compound and the cyclic ether compound include dimethoxyethane, ethoxymethoxy ethane, diethoxy ethane, tetrahydrofuran, dioxolan, dioxane, 1,2-bis (methoxycarbonyloxy) ethane, and 1,2-bis (ethoxycarbonyl). Oxy) ethane, 1,2-bis (ethoxycarbonyloxy) propane, ethylene glycol bis (trifluoroethyl) ether, propylene glycol bis (trifluoroethyl) ether, ethylene glycol bis (trifluoromethyl) ether, diethylene glycol bis (tri) Fluoroethyl) ether and the like can be mentioned, and among these, dioxolane is preferable.

The saturated chain ester compound is preferably a monoester compound or a diester compound having a total number of carbon atoms in the molecule of 2 to 8, and specific compounds include, for example, methyl formate, ethyl formate, methyl acetate, and acetate. Ethyl, propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, methyl malonate, ethyl malonate, methyl succinate, ethyl succinate, Methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethylene glycol diacetyl, propylene glycol diacetyl and the like can be mentioned, including methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate and methyl propionate. , And ethyl propionate are preferred.

As other organic solvents, for example, acetonitrile, propionitrile, nitromethane, derivatives thereof, and various ionic liquids can also be used.

Examples of the polymer used for preparing the composition in the form of a polymer gel include polyethylene oxide, polypropylene oxide, polyvinyl chloride, polyacrylonitrile, polymethylmethacrylate, polyethylene, polyvinylidene fluoride, polyhexafluoropropylene and the like.
Examples of the polymer used for preparing the composition in the polymer form include polyethylene oxide, polypropylene oxide, polystyrene sulfonic acid and the like.
The compounding ratio and the compounding method in the polymer gel form or the composition in the polymer form are not particularly limited, and a compounding ratio known in the present art and a known compounding method can be adopted.

The content of at least one compound selected from the group consisting of the compounds represented by the general formulas (1) to (4) is 0.01% by mass to 10% by mass with respect to the composition for an electrolyte of the present invention. It is preferably 0.05% by mass to 10% by mass, more preferably 0.1% by mass to 5% by mass. When the content of the compounds represented by the general formulas (1) to (4) is less than 0.01% by mass, the cycle characteristics and rate characteristics of the non-aqueous electrolyte secondary battery using the electrolyte composition of the present invention are used. The improvement effect of is not enough. On the other hand, if the content of the compounds represented by the general formulas (1) to (4) is more than 10% by mass, the effect commensurate with the blending amount cannot be obtained, and the battery characteristics may be adversely affected.

The form of the composition for an electrolyte of the present invention is not particularly limited, but a solvent-containing composition is preferable, and a liquid form is more preferable, because the production process is simple.

<Non-water electrolyte>
The non-aqueous electrolyte of the present invention includes the above-mentioned composition for an electrolyte and a supporting electrolyte. Examples of the supporting electrolyte include alkali metal salts such as lithium salt, sodium salt and potassium salt, magnesium salt, calcium salt and the like.

The lithium salt used for the non-aqueous electrolyte of the present invention is not particularly limited, and a known lithium salt can be used. Specific examples of the lithium salt include, for example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN. (SO ₂ F) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiB (CF ₃ SO ₃ ) ₄ , LiB (C ₂ O ₄ ) ₂ , LiBF ₂ (C ₂ O ₄ ), LiSbF ₆ , LiSiF ₅ , LiSCN _{, LiClO 4, LiCl, LiF,} LiBr, LiI, LiAlF 4, LiAlCl 4, LiPO 2 F 2 , and derivatives thereof.
The electrolyte compositions in liquid form and polymer gel form include LiPF ₆ , LiBF ₄ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN. (SO ₂ F) ₂ , LiPO ₂ F ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiCF ₃ SO ₃ derivative and LiC (CF ₃ SO ₂ ) ₃ derivative One or more lithium salts selected from the group. It is preferable to use.
Polymer-form electrolyte compositions include LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (SO ₂ F) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiB ( It is preferable to use one or more selected from the group consisting of _{CF 3} SO ₃ ) ₄ and LiB (C ₂ O ₄ ) _2.

The sodium salt and potassium salt used in the non-aqueous electrolyte of the present invention are not particularly limited, and known sodium salts and potassium salts can be used.

The magnesium salt and calcium salt used in the non-aqueous electrolyte of the present invention are not particularly limited, and known magnesium salts and calcium salts can be used.

If the concentration of the supporting electrolyte in the non-aqueous electrolyte is too low, sufficient current density may not be obtained, while if it is too high, the stability of the non-aqueous electrolyte may be impaired. Therefore, 0.5 mol / L. It is preferably ~ 7 mol / L, and more preferably 0.8 mol / L to 1.8 mol / L.

The application of the non-aqueous electrolyte of the present invention is not particularly limited, but it can be suitably used as a non-aqueous electrolyte used in a non-aqueous electrolyte secondary battery.

The non-aqueous electrolyte of the present invention may further contain known electrolyte additives such as an electrode film forming agent, an antioxidant, a flame retardant, and an overcharge inhibitor in order to improve battery life and safety. If the concentration of the electrolyte additive is too low, the additive effect cannot be exhibited, and if it is too high, it may adversely affect the characteristics of the non-aqueous electrolyte secondary battery. Therefore, it is 0 with respect to the non-aqueous electrolyte. It is preferably 0.01% by mass to 10% by mass, and more preferably 0.1% by mass to 5% by mass.

<Non-water electrolyte secondary battery>
The non-aqueous electrolyte secondary battery of the present invention includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and the above-mentioned non-aqueous electrolyte. In the present invention, it is preferable to interpose a separator between the positive electrode and the negative electrode. Hereinafter, the non-aqueous electrolyte secondary battery of the present invention will be described.

The positive electrode used in the present invention can be manufactured according to a known method. For example, an electrode mixture paste containing a positive electrode active material, a binder and a conductive auxiliary agent is applied to a current collector by applying an electrode mixture paste slurryed with an organic solvent or water to the current collector and dried, whereby the electrode mixture is applied onto the current collector. A layered positive electrode can be manufactured.

A known positive electrode active material can be used. Examples of known positive electrode active materials include lithium transition metal composite oxides, lithium-containing transition metal phosphoric acid compounds, lithium-containing silicate compounds, and lithium-containing transition metal sulfate compounds. As the transition metal of the lithium transition metal composite oxide, vanadium, titanium, chromium, manganese, iron, cobalt, nickel, copper and the like are preferable. Only one kind of these positive electrode active materials may be used, or two or more kinds thereof may be used in combination.

Specific examples of the lithium transition metal composite oxide include lithium cobalt composite oxides such _{as LiCoO 2} , lithium nickel composite oxides such as _{LiNiO 2} , and lithium manganese composite oxides such as _{LiMnO 2} , LiMn ₂ O ₄ , and Li ₂ MnO _3. Some of the transition metal atoms that are the main constituents of these lithium transition metal composite oxides are aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, lithium, nickel, copper, zinc, magnesium, gallium, zirconium, etc. Examples thereof include those substituted with other metals. Lithium transition metal composite oxides in which a part of the main transition metal atom is replaced with another metal are, for example, Li _1.1 Mn _1.8 Mg _0.1 O ₄ , Li _1.1 Mn _1.85 Al _0.05 O ₄ , LiNi _0.5 Co _0.2 Mn _0.3. O ₂ , LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.80 Co _0.17 Al _0.03 O ₂ , LiNi _0.80 Co _0.15 Al _0.05 O ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _0.2 Mn _0.2 O ₂ , LiMn _1.8 Al _0.2 O ₄ , LiNi _0.5 Mn _1.5 O ₄ , Li ₂ MnO _3- LiMO ₂ (M = Co, Ni, Mn) and the like.

The transition metal of the lithium-containing transition metal phosphate compound is preferably vanadium, titanium, manganese, iron, cobalt, nickel or the like, and specific examples thereof include LiFePO ₄ , LiM _x Fe _1-x PO ₄ (M = Co). , Ni, Mn) and other iron phosphate compounds, LiCoPO _{4 and} other phosphate cobalt compounds, and some of the transition metal atoms that are the main constituents of these lithium transition metal phosphate compounds are aluminum, titanium, vanadium, chromium, etc. Substituted with other metals such as manganese, iron, cobalt, lithium, nickel, copper, zinc, magnesium, gallium, zirconium, niobium, vanadium phosphate compounds such as _{Li 3} V ₂ (PO ₄ ) _{3 and the like.} Be done.

Examples of the lithium-containing silicate compound include Li ₂ FeSiO _{4 and the} like.

Examples of the lithium-containing transition metal sulfuric acid compound include LiFeSO ₄ , LiFeSO ₄ F and the like.

As the positive electrode active material, sulfur, sulfur-modified organic compounds, sulfur - may carbon composite, also be used _{Li 2 S x (x = 1~8} ).

As the sulfur, various forms such as powdered sulfur, insoluble sulfur, precipitated sulfur, colloidal sulfur and the like can be used. Powdered sulfur is preferable because it is uniformly dispersed in the electrode mixture paste.

The sulfur-modified organic compound is prepared by mixing sulfur with a polyacrylonitrile compound, an elastomer compound, a pitch compound, a polynuclear aromatic ring compound, an aliphatic hydrocarbon oxide, a polyether compound, a polythienoacene compound, a polyamide compound, a hexachlorobutadiene compound and the like. It can be produced by heat-modifying at 250 ° C. to 600 ° C. in a non-oxidizing gas atmosphere. The non-oxidizing gas atmosphere is an atmosphere in which the oxygen concentration is less than 5% by volume, preferably less than 2% by volume, and more preferably substantially free of oxygen, that is, nitrogen, helium, argon and the like. It is an active gas atmosphere or a sulfur gas atmosphere. From the viewpoint of obtaining a larger charge / discharge capacity, the sulfur content in the sulfur-modified organic compound is preferably 25% by mass to 80% by mass. Among these sulfur-modified organic compounds, a sulfur-modified polyacrylonitrile compound is preferable because a large charge / discharge capacity and stable cycle characteristics can be obtained.

Sulfur-carbon composites are those in which sulfur and carbon are mechanically composited, those in which sulfur and carbon are chemically composited, or elemental sulfur is contained in the pores of porous carbon. A substance that can be used as an electrode active material for a secondary battery, which can occlude and release lithium ions. The sulfur content in the sulfur-carbon complex is preferably 25% by mass to 90% by mass, preferably 30% by mass to 70%, because if it is too small, the charge / discharge capacity does not increase, and if it is too large, the electron conductivity decreases. More preferably by mass. As a method for supporting elemental sulfur in the pores of porous carbon, a known method can be adopted.

The sulfur content in the sulfur-modified organic compound and the sulfur-carbon complex can be calculated by elemental analysis using a CHN analyzer capable of analyzing sulfur and oxygen, for example, a vario MICRO cube manufactured by Elementer.

If the particle size of the positive electrode active material is too large, a uniform and smooth electrode mixture layer may not be obtained, while if it is too small, the handleability in the slurrying process deteriorates, so that the average particles of the positive electrode active material are average particles. The diameter (D50) is preferably 0.5 μm to 100 μm, more preferably 1 μm to 50 μm, and even more preferably 1 μm to 30 μm.

In the present invention, the average particle size (D50) means a 50% particle size measured by a laser diffraction light scattering method. The particle diameter is a volume-based diameter, and the laser diffracted light scattering method measures the diameter of secondary particles.

The positive electrode active material can have a desired particle size by a method such as pulverization or granulation. The pulverization may be performed by dry pulverization performed in a gas or wet pulverization performed in a liquid such as water. Examples of the industrial crushing method include ball mills, roller mills, turbo mills, jet mills, cyclone mills, hammer mills, pin mills, rotary mills, vibration mills, planetary mills, attritors, bead mills and the like.

As the binder, a known binder can be used. Specific examples of the binder include, for example, styrene-butadiene rubber, butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber, styrene-isoprene rubber, fluororubber, polyethylene, polypropylene, polyacrylamide, polyamide, polyamideimide, polyimide, and the like. Polyacrylonitrile, polyurethane, polyvinylidene fluoride, polytetrafluoroethylene, styrene-acrylic acid ester copolymer, ethylene-vinyl alcohol copolymer, polymethylmethacrylate, polyacrylate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, polyvinyl ether, Examples thereof include polyvinyl chloride, acrylic acid, polyacrylic acid, methyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose nanofibers, starch and the like. Only one kind of binder may be used, or two or more kinds of binders may be used in combination.

The content of the binder is preferably 0.5 part by mass to 30 parts by mass, and more preferably 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the positive electrode active material.

As the conductive auxiliary agent, a known conductive auxiliary agent for the electrode can be used. Specific examples of the conductive auxiliary agent include natural graphite, artificial graphite, coal tar pitch, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, roller black, disc black, and carbon. Carbon materials such as nanotubes, vapor grown carbon fiber (VGCF), flaky graphite, graphene, fullerene, needle coke; metal powders such as aluminum powder, nickel powder, titanium powder; zinc oxide, titanium oxide, etc. Conductive metal oxides of: La ₂ S ₃ , Sm ₂ S ₃ , Ce ₂ S ₃ , TiS _{2 and the} like.

The average particle size (D50) of the conductive auxiliary agent is preferably 0.0001 μm to 100 μm, and more preferably 0.01 μm to 50 μm.

The content of the conductive auxiliary agent is usually 0.1 part by mass to 50 parts by mass, preferably 0.5 part by mass to 30 parts by mass, and 1 part by mass to 3 parts by mass with respect to 100 parts by mass of the electrode active material. It is more preferably 20 parts by mass.

Solvents for preparing the positive electrode mixture paste include, for example, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethylmethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, acetonitrile, and pro. Pionitrile, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, nitromethane, N-methylpyrrolidone, N, N-dimethylformamide, dimethylacetamide, methylethylketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N , N-dimethylaminopropylamine, polyethylene oxide, tetrahydrofuran, dimethyl sulfoxide, sulfolane, γ-butyrolactone, water, alcohol and the like. The amount of the solvent used can be adjusted according to the coating method selected when coating the electrode mixture paste. For example, in the case of coating by the doctor blade method, the total of the positive electrode active material, the binder and the conductive auxiliary agent. The amount is preferably 15 parts by mass to 300 parts by mass, and more preferably 30 parts by mass to 200 parts by mass with respect to 100 parts by mass.

The positive electrode mixture paste contains, for example, other components such as a viscosity regulator, a reinforcing material, an antioxidant, a pH adjuster, and a dispersant, in addition to the above-mentioned components, as long as the effects of the present invention are not impaired. You may let it. As these other components, known ones can be used in known compounding ratios.

In the production of the electrode mixture paste, when the positive electrode active material, the binder and the conductive auxiliary agent are dispersed or dissolved in the solvent, all of them may be added to the solvent at once for dispersion treatment or separately added for dispersion treatment. You may. It is preferable to sequentially add the binder, the conductive auxiliary agent, and the positive electrode active material to the solvent in this order to perform the dispersion treatment because these can be uniformly dispersed in the solvent. When the electrode mixture paste contains other components, the other components can be added all at once for dispersion treatment, but it is preferable to perform dispersion treatment for each addition of one of the other components.

The method of dispersion treatment is not particularly limited, but industrial methods include, for example, ordinary ball mills, sand mills, bead mills, cyclone mills, pigment dispersers, grinders, ultrasonic dispersers, homogenizers, rotation / revolution mixers, and the like. A planetary mixer, fill mix, jet pacer, etc. can be used.

As the current collector, a conductive material such as titanium, titanium alloy, aluminum, aluminum alloy, nickel, stainless steel, nickel-plated steel, and carbon is used. Examples of the shape of the current collector include a foil shape, a plate shape, a net shape, a foam shape, a non-woven fabric shape, and the like, and the current collector may be either porous or non-porous. In addition, these conductive materials may be surface-treated in order to improve adhesion and electrical characteristics. Among these conductive materials, aluminum is preferable from the viewpoint of conductivity and price, and aluminum foil is particularly preferable. The thickness of the current collector is not particularly limited, but is usually 5 μm to 30 μm.

The method of applying the electrode mixture paste of the positive electrode onto the current collector is not particularly limited, but for example, the die coater method, the comma coater method, the curtain coater method, the spray coater method, the gravure coater method, the flexo coater method, and the knife coater. A method, a doctor blade method, a reverse roll method, a brush coating method, a dip method, or the like can be used. The die coater method, the knife coater method, the doctor blade method and the comma coater method are preferable in that a good surface condition of the coating layer can be obtained according to the viscosity and the drying property of the electrode mixture paste.

The positive electrode mixture paste may be applied to one side of the current collector or both sides of the current collector. When it is applied to both sides of the current collector, it may be applied sequentially on one side at a time, or it may be applied on both sides at the same time. Further, it may be applied continuously to the surface of the current collector, intermittently, or in stripes. The thickness, length and width of the coating layer can be appropriately determined according to the size of the battery and the like.

The method for drying the electrode mixture paste of the positive electrode applied on the current collector is not particularly limited, and a known method can be used. Examples of the drying method include drying with warm air, hot air, and low humidity air, vacuum drying, and drying by irradiating far infrared rays, infrared rays, electron beams, or the like, which is left in a heating furnace or the like. These drying methods may be carried out in combination. The temperature at the time of heating is generally about 50 ° C. to 180 ° C., but conditions such as temperature can be appropriately set according to the coating amount of the electrode mixture paste, the boiling point of the solvent used, and the like. By this drying, volatile components such as a solvent are volatilized from the coating film of the electrode mixture paste, and an electrode mixture layer is formed on the current collector.

When a lithium-free material such as a sulfur-modified organic compound and a sulfur-carbon composite is used as the positive electrode active material, lithium can be pre-doped. As a method for doping the material, a known method may be followed. For example, a semi-battery is assembled using metallic lithium as the counter electrode, and lithium is inserted by the electrolytic doping method in which lithium is electrochemically doped, or a metallic lithium foil is attached to an electrode and then left in an electrolytic solution. Then, a method of inserting lithium by a pasting doping method of doping using the diffusion of lithium to an electrode, a mechanical doping method of mechanically colliding a positive electrode active material with a lithium metal and inserting lithium, and the like can be mentioned. However, it is not limited to these.

The negative electrode used in the present invention can be manufactured according to a known method. For example, an electrode mixture paste containing a negative electrode active material, a binder and a conductive auxiliary agent is applied to a current collector by applying an electrode mixture paste slurryed with an organic solvent or water to the current collector and dried, whereby the electrode mixture is applied onto the current collector. A negative electrode having a layer formed can be manufactured.

A known negative electrode active material can be used. Known negative electrode active materials include, for example, natural graphite, artificial graphite, non-graphitizable carbon, easily graphitized carbon, lithium, lithium alloy, silicon, silicon alloy, silicon oxide, tin, tin alloy, tin oxide, phosphorus, germanium. , Indium, copper oxide, antimony sulfide, titanium oxide, iron oxide, manganese oxide, cobalt oxide, nickel oxide, lead oxide, ruthenium oxide, tungsten oxide, zinc oxide, LiVO ₂ , Li ₂ VO ₄ , Li ₄ Ti ₅ O _12, include composite oxides such as Chitan'niobu oxide. Only one kind of these negative electrode active materials may be used, or two or more kinds thereof may be used in combination.

As an anode active material, sulfur, sulfur-modified organic compounds, sulfur - may carbon composite, also be used _{Li 2 S x (x = 1~8} ). As the sulfur, sulfur-modified organic compound, and sulfur-carbon composite that can be used as the negative electrode active material, the same sulfur, sulfur-modified organic compound, and sulfur-carbon composite that can be used as the positive electrode active material shall be used. Can be done.

If the particle size of the negative electrode active material is too large, a uniform and smooth electrode mixture layer may not be obtained, while if it is too small, the handleability in the slurrying process deteriorates, so that the average particles of the negative electrode active material are average particles. The diameter (D50) is preferably 0.01 μm to 100 μm, more preferably 0.5 μm to 50 μm, and even more preferably 1 μm to 30 μm.

The negative electrode active material can have a desired particle size by a method such as pulverization or granulation. The pulverization may be performed by dry pulverization performed in a gas or wet pulverization performed in a liquid such as water. Examples of the industrial crushing method include a ball mill, a roller mill, a turbo mill, a jet mill, a cyclone mill, a hammer mill, a pin mill, a rotary mill, a vibration mill, a planetary mill, an attritor, and a bead mill.

A known binder can be used. Specific examples of the binder include the same binders used for the positive electrode. Only one kind of binder may be used, or two or more kinds of binders may be used in combination.

The content of the binder is preferably 1 part by mass to 30 parts by mass, and more preferably 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the negative electrode active material.

As the conductive auxiliary agent, a known conductive auxiliary agent for the electrode can be used. Specific examples of the conductive auxiliary agent include the same conductive auxiliary agents used for the positive electrode.

The average particle size (D50) of the conductive auxiliary agent is preferably 0.0001 μm to 100 μm, and more preferably 0.01 μm to 50 μm.

The content of the conductive auxiliary agent is usually 0 parts by mass to 50 parts by mass, preferably 0 parts by mass to 30 parts by mass, and 0.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the electrode active material. It is more preferable that it is a part.

Examples of the solvent for preparing the electrode mixture paste for the negative electrode include the same solvents as those used for preparing the electrode mixture paste for the positive electrode. The amount of the solvent used can be adjusted according to the coating method selected when coating the electrode mixture paste. For example, in the case of coating by the doctor blade method, the total of the negative electrode active material, the binder and the conductive auxiliary agent. The amount is preferably 15 parts by mass to 300 parts by mass, and more preferably 30 parts by mass to 200 parts by mass with respect to 100 parts by mass.

The electrode mixture paste for the negative electrode contains, for example, other components such as a viscosity regulator, a reinforcing material, an antioxidant, a pH adjuster, and a dispersant, in addition to the above-mentioned components, as long as the effects of the present invention are not impaired. You may let it. As these other components, known ones can be used in known compounding ratios.

The negative electrode mixture paste can be produced by blending, dispersing and producing in the same process as the production process of the positive electrode mixture paste, except that the negative electrode active material is used instead of the positive electrode active material.

As the current collector, a conductive material such as titanium, titanium alloy, aluminum, aluminum alloy, copper, nickel, stainless steel, nickel-plated steel, and carbon is used. Examples of the shape of the current collector include a foil shape, a plate shape, a net shape, a foam shape, a non-woven fabric shape, and the like, and the current collector may be either porous or non-porous. In addition, these conductive materials may be surface-treated in order to improve adhesion and electrical characteristics. Among these conductive materials, copper is preferable from the viewpoint of stability at the negative electrode potential, conductivity, and price, and copper foil is particularly preferable. The thickness of the current collector is not particularly limited, but is usually 3 μm to 30 μm.

When the negative electrode active material is a metal or metal alloy such as lithium, lithium alloy, tin, tin alloy, the electrode mixture paste is not prepared using a binder, a conductive auxiliary agent, or a solvent, and the metal or alloy is made into a plate, for example. It can also be used in the form of a sheet, a film, or the like. Further, when the alloy is used as the negative electrode active material, it is not necessary to use a current collector because the negative electrode active material itself has high electron conductivity, but depending on the configuration of the battery, an alloy is formed with the negative electrode active material. It is also possible to use a non-metal material as a negative electrode current collector.

The method of applying the electrode mixture paste of the negative electrode onto the current collector is not particularly limited, and examples thereof include a coating method used when manufacturing a positive electrode.

The negative electrode mixture paste may be applied to one side of the current collector or both sides of the current collector. When it is applied to both sides of the current collector, it may be applied sequentially on one side at a time, or it may be applied on both sides at the same time. Further, it may be applied continuously to the surface of the current collector, intermittently, or in stripes. The thickness, length and width of the coating layer can be appropriately determined according to the size of the battery and the like.

The method for drying the electrode mixture paste of the negative electrode applied on the current collector is not particularly limited, and a known method can be used. Examples of the drying method include drying with warm air, hot air, and low humidity air, vacuum drying, and drying by irradiating far infrared rays, infrared rays, electron beams, or the like, which is left in a heating furnace or the like. These drying methods may be carried out in combination. The temperature at the time of heating is generally about 50 ° C. to 180 ° C., but conditions such as temperature can be appropriately set according to the coating amount of the electrode mixture paste, the boiling point of the solvent used, and the like. By this drying, volatile components such as a solvent are volatilized from the coating film of the electrode mixture paste, and an electrode mixture layer is formed on the current collector.

When a material having a large initial irreversible reaction, such as silicon-based, tin-based, or sulfur-based, is used as the negative electrode active material, lithium can be doped in advance. As a method for doping the material, a known method may be followed. For example, a semi-battery is assembled using metallic lithium as the counter electrode, and lithium is inserted by the electrolytic doping method in which lithium is electrochemically doped, or a metallic lithium foil is attached to an electrode and then left in an electrolytic solution. Then, a method of inserting lithium by a pasting doping method of doping using the diffusion of lithium to an electrode, a mechanical doping method of mechanically colliding a negative electrode active material with a lithium metal and inserting lithium, and the like can be mentioned. However, it is not limited to these.

As the separator, a commonly used polymer film, glass film or the like can be used without particular limitation. Specific examples of the polymer film include polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyethylene oxide and polypropylene. Polymer compounds and derivatives thereof mainly composed of polyethers such as oxides, various celluloses such as carboxymethyl cellulose and hydroxypropyl cellulose, poly (meth) acrylic acid and various esters thereof, and copolymers thereof. Examples thereof include films made of a mixture, and these films may be coated with a ceramic material such as alumina or silica, magnesium oxide, an aramid resin, or polyvinylidene chloride. These films can be used alone, or these polymer films can be laminated and used as a multi-layer film. Further, various additives can be used for these polymer films, and the type and content thereof are not particularly limited. Among these polymer films, a film made of polyethylene, polypropylene, polyvinylidene fluoride, or polysulfone is preferably used.

These polymer films are microporous so that non-aqueous electrolytes can penetrate and ions can easily permeate. The microporous method includes a "phase separation method" in which a solution of a polymer compound and a solvent is microphase-separated to form a film, and the solvent is extracted and removed to make the polymer porous, and a high draft of the molten polymer compound. The "stretching method", in which the crystals are extruded and then heat-treated to arrange the crystals in one direction and then stretched to form gaps between the crystals to make them porous, is appropriately selected depending on the polymer film to be used. To.

The shape of the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, and batteries having various shapes such as a coin-type battery, a cylindrical battery, a square battery, and a laminated battery can be used. FIG. 1 is a vertical sectional view schematically showing an example of the structure of a coin-type battery of the non-aqueous electrolyte secondary battery of the present invention. FIG. 2 is a schematic view showing a basic configuration of a cylindrical battery of the non-aqueous electrolyte secondary battery of the present invention. FIG. 3 is a perspective view showing the internal structure of the cylindrical battery of the non-aqueous electrolyte secondary battery of the present invention as a cross section.

The coin-type non-aqueous electrolyte secondary battery 10 shown in FIG. 1 has a positive electrode current collector 1a, a positive electrode mixture layer 1 formed on the positive electrode current collector 1a and capable of emitting lithium ions, a positive electrode current collector 1a, and a positive electrode current collector 1a. A positive electrode case 4 for accommodating a positive electrode composed of a positive electrode mixture layer 1, a negative electrode current collector 2a, and lithium ions formed on the negative electrode current collector 2a and emitted from the positive electrode mixture layer 1 are stored and released. It includes a negative electrode mixture layer 2 that can be formed, a negative electrode case 5 that houses a negative electrode composed of a negative electrode current collector 2a and a negative electrode mixture layer 2, and a separator 7. The inside of the positive electrode case 4 and the negative electrode case 5 is filled with the non-aqueous electrolyte 3. Further, the peripheral portions of the positive electrode case 4 and the negative electrode case 5 are sealed by being crimped via a polypropylene gasket 6.

The cylindrical non-aqueous electrolyte secondary battery 10'shown in FIGS. 2 and 3 includes an electrode body in which a negative electrode plate 19 and a positive electrode plate 21 are wound via a separator 7, and a case 23 for accommodating the electrode body. , A pair of insulating plates 24 arranged so as to sandwich the electrode body. The positive electrode plate 21 is composed of a positive electrode current collector 1a and a positive electrode mixture layer 1 formed on the positive electrode current collector 1a and capable of emitting lithium ions. The negative electrode plate 19 is composed of a negative electrode current collector 2a and a negative electrode mixture layer 2 formed on the negative electrode current collector 2a and capable of storing and releasing lithium ions released from the positive electrode mixture layer 1. The inside of the case 23 is filled with the non-aqueous electrolyte 3. At the open end of the case 23, the positive electrode terminal 17, the safety valve 26 provided inside the positive electrode terminal 17, and the PTC (Positive Temperature Coefficient) element 27 are sealed by being crimped via the gasket 6. The negative electrode plate 19 is connected to the negative electrode terminal 18 via the negative electrode lead 20. The positive electrode plate 21 is connected to the positive electrode terminal 17 via the positive electrode lead 22.

Examples of the exterior member used for the positive electrode case 4, the negative electrode case 5, and the case 23 include a metal container, a laminated film, and the like. The thickness of the exterior member is usually 0.5 mm or less, preferably 0.3 mm or less. Examples of the shape of the exterior member include a flat type (thin type), a square type, a cylindrical type, a coin type, and a button type.

The metal container can be formed from, for example, stainless steel, aluminum, an aluminum alloy, or the like. As the aluminum alloy, an alloy containing elements such as magnesium, zinc, and silicon is preferable. By reducing the content of transition metals such as iron, copper, nickel, and chromium to 1% by mass or less in aluminum or aluminum alloy, long-term reliability and heat dissipation in a high temperature environment can be dramatically improved. ..

As the laminated film, a multilayer film having a metal layer between resin films can be used. The metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction. As the resin film, for example, a polymer material such as polypropylene, polyethylene, nylon, or polyethylene terephthalate can be used. The laminated film can be sealed by heat fusion to form an exterior member.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. As long as it does not deviate from the gist of the present invention, it can be carried out in various forms with modifications, improvements, etc. that can be made by those skilled in the art.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples.

<Preparation of positive electrode A>
_{94.0 parts by mass of NCM622 (LiNi 0.6} Co _0.2 Mn _0.2 O ₂ , manufactured by Beijing) as a positive electrode active material, 3.0 parts by mass of acetylene black (Denka Black, manufactured by Denka) as a conductive auxiliary agent, and a binder. Using 3.0 parts by mass of polyvinylidene fluoride (manufactured by Kureha Co., Ltd.) and 90 parts by mass of N-methylpyrrolidone as a solvent, the mixture was dispersed using a planetary mixer to obtain a slurry-like electrode mixture paste. This electrode mixture paste was applied to one side of a current collector made of aluminum foil (thickness 15 μm) by the doctor blade method, dried at 90 ° C., and then press-molded. Then, the electrode was cut to a predetermined size, and immediately before use, it was vacuum dried at 130 ° C. for 3 hours to prepare a positive electrode A.

<Manufacturing of negative electrode A>
96.6 parts by mass of artificial graphite (MAGD: manufactured by Hitachi Chemical) as the negative electrode active material, 0.4 parts by mass of acetylene black (Denka Black, manufactured by Denka) as the conductive auxiliary agent, and styrene-butadiene rubber (40) as the binder. Using a planetary mixer with 2.0 parts by mass of mass% aqueous dispersion (manufactured by Nippon Zeon), 1.0 part by mass of sodium carboxymethyl cellulose (CMCNa: manufactured by Daicel FineChem), and 120 parts by mass of water as a solvent. To obtain a slurry-like electrode mixture paste. This electrode mixture paste was applied to one side of a current collector made of a copper foil (thickness 10 μm) by the doctor blade method, dried at 90 ° C., and then press-molded. Then, the electrode was cut to a predetermined size and further vacuum dried at 130 ° C. for 3 hours immediately before use to prepare a negative electrode A.

<Battery production-1>
[Example 1]
_{A solution was prepared in which LiPF 6} as a supporting electrolyte was dissolved at a concentration of 1.0 mol / L in a mixed solvent consisting of 50% by volume of ethylene carbonate and 50% by volume of diethyl carbonate. To this, 1.0% by mass of compound 1-1 was added to obtain a non-aqueous electrolyte.
A positive electrode A cut into a disk shape and a negative electrode A cut into a disk shape were used, and a polypropylene film (manufactured by Cellguard) was sandwiched as a separator and held in the case. Then, the non-aqueous electrolyte prepared above was injected into the case and sealed with a caulking machine to prepare a non-aqueous electrolyte secondary battery (φ20 mm, thickness 3.2 mm, coin type) of Example 1. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-1, and the results are shown in Table 1.

[Example 2]
The non-aqueous electrolyte secondary battery of Example 2 was produced in the same manner as in Example 1 except that 0.1% by mass of Compound 1-1 was added to the non-aqueous electrolyte. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-1, and the results are shown in Table 1.

[Example 3]
The non-aqueous electrolyte secondary battery of Example 3 was produced in the same manner as in Example 1 except that 5.0% by mass of Compound 1-1 was added to the non-aqueous electrolyte. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-1, and the results are shown in Table 1.

[Examples 4 to 25]
The non-aqueous electrolyte secondary batteries of Examples 4 to 25 were prepared in the same manner as in Example 1 except that the compounds shown in Table 1 were added to the non-aqueous electrolyte in place of Compound 1-1. The numbers in parentheses attached to the compound numbers in Table 1 indicate the weight fraction (% by mass) of each added compound in the non-aqueous electrolyte. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-1, and the results are shown in Table 1.

[Comparative Examples 1 to 7]
The non-aqueous electrolyte secondary batteries of Comparative Examples 1 to 7 were prepared in the same manner as in Example 1 except that the following compounds 5-1 to 5-7 were added to the non-aqueous electrolyte in place of Compound 1-1. .. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-1, and the results are shown in Table 1.

[Comparative Example 8]
The non-aqueous electrolyte secondary battery of Comparative Example 8 was produced by the same operation as in Example 1 except that compound 1-1 was not added. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-1, and the results are shown in Table 1.

<Charging / discharging evaluation-1>
The non-aqueous electrolyte secondary batteries of Examples 1 to 25 and Comparative Examples 1 to 8 were placed in a constant temperature bath at 25 ° C., the charge termination voltage was 4.20V, the discharge termination voltage was 2.75V, and the charging rate was 0.2C. The charge / discharge test at a discharge rate of 0.2 C was performed 5 times, and the charge / discharge test at a charge rate of 2C and a discharge rate of 2C was performed 5 times. After that, it was placed in a constant temperature bath at 45 ° C., and a total of 110 charge / discharge tests were performed at a charge rate of 0.5 C and a discharge rate of 0.5 C 100 times to measure the discharge capacity (mAh / g) per positive electrode active material. .. The ratio of the 5th discharge capacity to the 10th discharge capacity (L1), and the ratio of the 110th discharge capacity to the 11th discharge capacity (L2, L2 = 110th discharge capacity / 11th discharge capacity) Is shown in Table 1.

<Manufacturing of sulfur-modified polyacrylonitrile>
After putting a mixture of 200 parts by mass of sulfur (manufactured by Sigma Aldrich, particle diameter 200 μm, powder) and 100 parts by mass of polyacrylonitrile powder (manufactured by Sigma Aldrich, classified by a sieve having an opening diameter of 30 μm) into an alumina tanman tube. , The opening of the alumina tanman tube was covered with a rubber stopper to which a thermocouple, a gas introduction tube and a gas discharge tube were attached. The mixture was heated at a heating rate of 5 ° C./min while introducing argon gas into the alumina tanman tube at a flow rate of 100 cc / min, and the argon gas was stopped when the temperature reached 100 ° C. After that, the heating was stopped at 360 ° C, but the temperature rose to 400 ° C. After cooling to around room temperature, the reaction product was taken out from the alumina tanman tube. The resulting reaction product was pulverized to give sulfur-modified polyacrylonitrile (sometimes referred to as SPAN). The average particle size and sulfur content of SPAN were as follows.
・ Average particle diameter 10 μm
・ Sulfur content 38.4% by mass

<Preparation of positive electrode B>
90.0 parts by mass of SPAN as a positive electrode active material, 5.0 parts by mass of acetylene black (Denka Black, manufactured by Denka) as a conductive auxiliary agent, and styrene-butadiene rubber (40% by mass water dispersion, manufactured by Nippon Zeon) as a binder. ) Was 3.0 parts by mass, sodium carboxymethyl cellulose (CMCNa, manufactured by Daicel FineChem) was 2.0 parts by mass, and 120 parts by mass of water was used as a solvent. An agent paste was obtained. This electrode mixture paste was applied to one side of a current collector made of carbon-coated aluminum foil (thickness 22 μm) by the doctor blade method, dried at 90 ° C., and then press-molded. Then, the electrode was cut to a predetermined size, and immediately before use, it was vacuum dried at 130 ° C. for 3 hours. Then, using metallic lithium as a counter electrode, a half-cell using the non-aqueous electrolyte of Comparative Example 8 was assembled, and lithium was electrochemically doped to prepare a positive electrode B.

<Battery production-2>
[Example 26]
_{A solution was prepared in which LiPF 6} was dissolved at a concentration of 1.0 mol / L in a mixed solvent consisting of 50% by volume of ethylene carbonate and 50% by volume of diethyl carbonate. Compound 1-37 was added thereto in an amount of 1.0% by mass to obtain a non-aqueous electrolyte.
A positive electrode B cut into a disk shape and a negative electrode A cut into a disk shape were used, and a polypropylene film (manufactured by Cellguard) was sandwiched as a separator and held in the case. Then, the non-aqueous electrolyte prepared above was injected into the case and sealed with a caulking machine to prepare a non-aqueous electrolyte secondary battery (φ20 mm, thickness 3.2 mm, coin type) of Example 26. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-2, and the results are shown in Table 2.

[Examples 27 to 29]
The non-aqueous electrolyte secondary batteries of Examples 27 to 29 were prepared in the same manner as in Example 26 except that the compounds shown in Table 2 were added instead of Compounds 1-37. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-2, and the results are shown in Table 2.

[Comparative Example 9]
The non-aqueous electrolyte secondary battery of Comparative Example 9 was produced by the same operation as in Example 26 except that Compound 1-37 was not added. The cycle characteristics and rate characteristics of the produced non-aqueous electrolyte secondary battery were evaluated by the method of charge / discharge evaluation-2, and the results are shown in Table 2.

<Charging / discharging evaluation-2>
The non-aqueous electrolyte secondary batteries of Examples 26 to 29 and Comparative Example 9 were placed in a constant temperature bath at 25 ° C., the end-of-charge voltage was 3.0 V, the end-of-discharge voltage was 0.7 V, the charge rate was 0.2 C, and the discharge rate. The charge / discharge test of 0.2C was performed 5 times, and the charge / discharge test of the charge rate 2C and the discharge rate 2C was further performed 5 times. After that, it was placed in a constant temperature bath at 45 ° C., and a total of 110 charge / discharge tests were performed at a charge rate of 0.5 C and a discharge rate of 0.5 C 100 times to measure the discharge capacity (mAh / g) per positive electrode active material. .. The ratio of the 5th discharge capacity to the 10th discharge capacity (L3), and the ratio of the 110th discharge capacity to the 11th discharge capacity (L4, L4 = 110th discharge capacity / 11th discharge capacity) Is shown in Table 2.

From the results in Tables 1 and 2, by using the composition for an electrolyte of the present invention, a non-aqueous electrolyte secondary battery having improved cycle characteristics and rate characteristics at the same time can be produced.

1 Positive electrode mixture layer 1a Positive electrode current collector 2 Negative electrode mixture layer 2a Negative electrode current collector 3 Non-aqueous electrolyte 4 Positive electrode case 5 Negative electrode case 6 Gasket 7 Separator 10 Coin-type non-aqueous electrolyte secondary battery 10'Cylindrical non- Water Electrode Secondary Battery 17 Positive Electrode Terminal 18 Negative Electrode Terminal 19 Negative Electrode Plate 20 Negative Electrode Lead 21 Positive Electrode Plate 22 Positive Electrode Lead 23 Case 24 Insulation Plate 26 Safety Valve 27 PTC Element

Claims (8)

At least one compound selected from the group consisting of the compounds represented by the following general formulas (1) to (4), and
A composition for an electrolyte containing at least one selected from a solvent and a dispersion medium.

(In the formula, R ¹ is a hydrocarbon group having 1 to 8 carbon atoms, and R ^{2 to} R ⁵ are independently a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, and 1 carbon atom. An alkoxy group of ~ 6 or the following formula (1-a), where R ⁶ is a nitro group, a sulfonic acid group, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and the following formula. (1-b) or the following formula (1-c), when R ⁶ is a hydrocarbon group having 1 to 8 carbon atoms, n = an integer of 1 to 4, and R ⁶ is nitro. A group, a sulfonic acid group, an alkoxy group having 1 to 6 carbon atoms, or n = 1 when the formula (1-b) ^{is described below, and when R 6} is the formula (1-c) below. , N = 2.)

(* In the formula indicates the connection position.)

(In the formula, R ⁷ is the following formula (1-d) or the following formula (1-e).)

(In the formula, R ^{8 to} R ¹⁶ each independently have a hydrogen atom, an unsubstituted hydrocarbon group having 1 to 8 carbon atoms, and a part of the hydrogen atom substituted with a fluorine atom to have 1 to 8 carbon atoms. Hydrocarbon group, unsubstituted alkoxy group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms in which a part of hydrogen atom is substituted with a fluorine atom, and unsubstituted carbon atom number 1 to 6 A thioalkoxy group, a thioalkoxy group having 1 to 6 carbon atoms in which a part of hydrogen atoms is replaced with a fluorine atom, a sulfonyl group having a hydrocarbon group having 1 to 8 carbon atoms, or a carbide having 1 to 8 carbon atoms. It is an acyl group having a hydrogen group, and * indicates the bond position.)

(In the formula, m = 1 or 2, and when m = 1, R ^{17 to} R ¹⁹ are each independently a hydrocarbon group having 1 to 8 carbon atoms, and R ¹⁸ and R ¹⁹ are linked. When m = 2, R ¹⁷ and R ¹⁹ are each independently a hydrocarbon group having 1 to 8 carbon atoms, and R ¹⁸ is a single bond.)

(In the formula, R ²⁰ and R ²¹ are each independently a hydrocarbon group having 1 to 8 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and R ^{22 to} R ³¹ are independent hydrogen groups, respectively. Atom, hydrocarbon group with 1 to 8 carbon atoms, alkoxy group with 1 to 6 carbon atoms, halogen atom or nitro group). ^{The composition for an electrolyte according to claim 1, which contains a compound in which R 1} in the general formula (1) is a methyl group, an allyl group, a t-butyl group or a benzyl group. ^{R 7} in the general formula (2) is the formula (1-d), R ⁸ , R ⁹ , R ¹¹ and R ¹² in the formula (1-d) are hydrogen atoms, and R ¹⁰ is a methoxy group. , The composition for an electrolyte according to claim 1, which contains a compound which is a thiomethoxy group, a trifluoromethoxy group or a methyl sulfonyl group. ^{The electrolyte according to claim 1, wherein R 7} in the general formula (2) is the formula (1-e), and R ^{14 to} R ¹⁶ in the formula (1-e) contain a compound which is a hydrogen atom. Composition. The composition for an electrolyte according to claim 1, which contains a compound ^{in which R 17} in the general formula (3) is a methyl group or an ethyl group. In the general formula (4), R ²⁰ and R ²¹ are methyl groups, R ²⁴ and R ²⁹ are hydrogen atoms or nitro groups, and R ²² , R ²³ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , and so on. The composition for an electrolyte according to claim 1, which contains a compound in which ^{R 30} and R ^{31 are hydrogen atoms.} The composition for an electrolyte according to any one of claims 1 to 6 and the composition for an electrolyte.
Non-aqueous electrolytes, including supporting electrolytes. With the positive electrode
With the negative electrode
A non-aqueous electrolyte secondary battery comprising the non-aqueous electrolyte according to claim 7.

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