WO2018211896A1 - Vinyl sulfone compound, electrolytic solution for lithium ion battery, and lithium ion battery - Google Patents

Abstract

The purpose of the present invention is to provide a vinyl sulfone compound and the like which exhibits excellent storage stability when stored long-term in a non-aqueous solvent and, when used in a lithium ion battery, exhibits less decrease in volume after a high-temperature storage test than in prior art. This vinyl sulfone compound has a structure represented by general formula (I) wherein A represents an optionally substituted trivalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heteroaromatic hydrocarbon group, and R₁ represents general formula (II) or general formula (III).

Description

Vinylsulfone compound, electrolyte for lithium ion battery, and lithium ion battery

The present invention relates to a vinyl sulfone compound, an electrolytic solution for a lithium ion battery, and a lithium ion battery, and in particular, has excellent storage stability when stored in a non-aqueous solvent for a long period of time, and has a high temperature when used in a lithium ion battery. The present invention relates to a vinyl sulfone compound and the like that can improve a decrease in capacity after a storage test and improve cycle characteristics related to life and initial charge / discharge efficiency.

In recent years, the demand for energy saving has been increasing, and the technology related to power storage has become important. As batteries used for power storage, lithium ion batteries, sodium ion batteries, nickel metal hydride batteries, and the like are known. Among the batteries, lithium ion batteries are used in various applications such as in-vehicle applications and power supplies for mobile phones because of their high energy density and low cost per unit capacity.

Lithium ion batteries are expected to be used in various applications in addition to the above applications. For example, it is expected to be used as a power source for wearable or flexible electronics such as smart glasses, smart watches, and organic EL lighting, and in high temperature environments, and further safety is required.

As a lithium ion battery, for example, an electrolyte type lithium ion battery including a positive electrode, a negative electrode, a separator, and a nonaqueous electrolytic solution containing a lithium salt is known.
There is also known a so-called all-solid-state lithium ion battery configured by an electrolyte formed of a solid material without using an electrolyte of a non-aqueous electrolyte solution.
As a lithium ion battery using such a solid electrolyte, by containing a vinyl sulfone compound having a hydroxy group (OH group) (Comparative Compound 1 having the structure shown below) in the electrolyte, the ion conductivity is high. In addition, there is disclosed a technique for producing a secondary battery that does not leak and has excellent discharge characteristics at low temperatures (see, for example, Patent Documents 1 to 3).

However, the vinyl sulfone compound having a hydroxy group described above has poor long-term storage stability in a non-aqueous solvent, and there are problems such as precipitation (precipitation) when stored in a solution state for a long time. Moreover, in the lithium ion battery using the vinyl sulfone compound having a hydroxy group, the capacity is lowered after the high temperature storage test, that is, the life is a problem.

JP 2000-17076 A JP 2000-21446 A JP 2002-190323 A

The present invention has been made in view of the above problems and circumstances, and its solution is excellent in storage stability when stored for a long time in a non-aqueous solvent, and when used in a lithium ion battery, it has a high temperature. An object is to provide a vinyl sulfone compound capable of improving the reduction in capacity after a storage test and improving the cycle characteristics related to life and the initial charge / discharge efficiency. Furthermore, it is providing the electrolyte solution for lithium ion batteries, and a lithium ion battery.

In the process of studying the cause of the above problem in order to solve the above problems, the present inventor in the vinyl sulfone compound having the above hydroxy group (Comparative Compound 1) converts the hydroxy group to a specific substituent, particularly the number of carbon atoms. By replacing with an acyl group of 4 or less, it has excellent long-term storage stability in a non-aqueous solvent by acting preferentially on the interaction or film formation on the negative electrode or positive electrode surface, and the lithium ion battery after the high temperature storage test The present inventors have found that the reduction in capacity is improved and further that the cycle characteristics and the initial charge / discharge efficiency are improved, and the present invention has been achieved.
That is, the said subject which concerns on this invention is solved by the following means.

1. A vinyl sulfone compound having a structure represented by the following general formula (I).

[In General Formula (I), A represents a trivalent aliphatic hydrocarbon group, aromatic hydrocarbon group or heteroaromatic hydrocarbon group which may have a substituent. R ₁ represents the following general formula (II) or the following general formula (III). ]

[In the general formula (II), R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, a halogen atom or an alkyl group, an aryl group, an alkoxy group. Represents an aryloxy group or —NR ₄ R ₅ . R ₄ and _{R 5} represents an alkyl group or an aryl group. -* Represents a bond with an oxygen atom.
In the general formula (III), R ₃ is an alkenyl group, an alkynyl group, an aryl group optionally substituted with a halogen atom, an alkyl group or a cycloalkyl group, an aryl group optionally substituted with a halogen atom or an alkyl group, Represents an alkoxy group, an aryloxy group or —NR ₄ R ₅ ; R ₄ and R ₅ represent an alkyl group or an aryl group. -* Represents a bond with an oxygen atom. ]

2. The vinyl sulfone compound according to item 1, wherein the compound having a structure represented by the general formula (I) is a compound having a structure represented by the following general formula (IV).

[In General Formula (IV), R ₆ represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group, aryl group or alkoxy group. R ₁ has the same meaning as _{R 1} in the general formula (I). ]

3. The vinyl sulfone compound according to item 2, wherein R _{6 of the} compound having a structure represented by the general formula (IV) is a hydrogen atom.

4). In the general formula (I), R ₁ is represented by the general formula (II),
The vinyl according to any one of items 1 to 3, wherein, in the general formula (II), R ₂ represents an alkyl group having 1 to 6 carbon atoms or a fluorinated alkyl group having 1 to 6 carbon atoms. Sulfone compounds.

5). In the general formula (I), R ₁ is represented by the general formula (II),
The vinyl sulfone compound according to any one of Items 1 to 4, wherein, in the general formula (II), R ₂ is an alkyl group having 1 to 3 carbon atoms.

6). In the general formula (I), R ₁ is represented by the general formula (III),
The vinyl according to any one of items 1 to ₃ , wherein, in the general formula (III), R ₃ represents an alkyl group having 1 to 6 carbon atoms or a fluorinated alkyl group having 1 to 6 carbon atoms. Sulfone compounds.

7. The vinyl sulfone compound according to any one of items 1 to 6, wherein the compound having a structure represented by the general formula (I) is a material added to an electrolyte for a lithium ion battery.

8. The electrolyte solution for lithium ion batteries containing the vinyl sulfone compound as described in any one of Claim 1 to 7.

9. The electrolyte solution for a lithium ion battery according to item 8, which contains at least one carbonate of a chain carbonate and a cyclic carbonate.

10. Item 10. The electrolyte solution for a lithium ion battery according to Item 8 or 9, wherein the content of the vinyl sulfone compound is in the range of 0.01 to 5.0 mass% with respect to the total amount of the electrolyte solution.

11. The lithium ion battery which contains the vinyl sulfone compound as described in any one of Claim 1 to 7 in electrolyte solution.

12. Item 12. The lithium ion battery according to item 11, having a negative electrode made of an active material containing natural graphite or artificial graphite which is a carbonaceous material.

13. Item 13. The lithium ion battery according to Item 11 or 12, which has a negative electrode made of a carbonaceous material active material containing at least one atom selected from the group consisting of Si atom, Sn atom and Pb atom.

14. 14. The lithium ion battery according to item 13, having a negative electrode made of a carbonaceous material active material containing Si atoms.

15. Item 15. The lithium ion battery according to any one of Items 11 to 14, having a positive electrode made of an active material containing any one of a lithium transition metal composite oxide or a lithium-containing transition metal phosphate compound.

16. 16. The lithium ion battery according to claim 15, having a positive electrode made of an active material containing a lithium transition metal composite oxide.

By the above means of the present invention, it has excellent storage stability when stored in a non-aqueous solvent for a long period of time, and when used in a lithium ion battery, improves the decrease in capacity after a high-temperature storage test. It is possible to provide a vinyl sulfone compound capable of improving cycle characteristics related to life and initial charge / discharge efficiency. Furthermore, the electrolyte solution for lithium ion batteries and the lithium ion battery using the said vinyl sulfone compound can be provided.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
The vinyl sulfone compound having the hydroxy group (Comparative Compound 1) is likely to undergo polymerization due to the addition reaction due to the action of the hydroxy group. Therefore, when the Comparative Compound 1 is contained in a non-aqueous solvent, it becomes a gel and precipitates. Things will precipitate.
Therefore, as in the present invention, the hydroxy group is capped (cap formation; protective group formation) with the structure represented by the general formula (II) or general formula (III), and the general formula (I) or By adopting the structure represented by the general formula (IV), it is presumed that polymerization due to the addition reaction is suppressed. As a result, when stored for a long time in a non-aqueous solvent, precipitation is not generated and the storage stability is excellent. In addition, a film formed by having a substituent represented by the general formula (II) or the general formula (III), particularly an acyl group having 4 or less carbon atoms, easily interacts with the positive electrode or the negative electrode with respect to the hydroxy group. However, it is easy to follow the expansion and contraction of the electrode itself, and when it is a lithium ion battery, it not only excels in storage stability of the electrolyte solution but also improves capacity reduction after a high temperature storage test. Therefore, it is possible to improve battery characteristics such as cycle characteristics and initial charge / discharge efficiency of the lithium ion battery.

The vinyl sulfone compound of the present invention has a structure represented by the above general formula (I). This feature is a technical feature common to or corresponding to the claimed invention.
In an embodiment of the present invention, the compound having the structure represented by the general formula (I) is a compound having the structure represented by the general formula (IV). And preferred from the viewpoint of long-term storage stability in a non-aqueous solvent.

In the general formula (I), R ₁ is represented by the general formula (II). In the general formula (II), R ₂ is an alkyl group having 1 to 6 carbon atoms or 1 to 6 carbon atoms. Is preferably from the viewpoint of solubility in a non-aqueous solvent and long-term storage stability in a non-aqueous solvent. In the case of a fluorinated alkyl group, the safety of a lithium ion battery ( It is preferable in terms of nonflammability.
In the general formula (I), R ₁ is represented by the general formula (III), and in the general formula (III), R ₃ is an alkyl group having 1 to 6 carbon atoms or a group having 1 to 6 carbon atoms. It is preferable to represent a fluorinated alkyl group from the viewpoints of solubility in a non-aqueous solvent and long-term storage stability in a non-aqueous solvent. In the case of a fluorinated alkyl group, the safety of the lithium ion battery ( It is preferable in terms of nonflammability.

Further, the compound having the structure represented by the general formula (I) is a material added to the electrolyte solution for a lithium ion battery, so that the long-term storage stability of the electrolyte solution for the lithium ion battery is excellent. When it uses for a battery, it is preferable at the point which can improve the fall of the capacity | capacitance after the high temperature storage test of a lithium ion battery.

The vinyl sulfone compound of the present invention is suitably used for an electrolyte for a lithium ion battery or a lithium ion battery.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[Vinyl sulfone compound]
The vinyl sulfone compound of the present invention has a structure represented by the following general formula (I).

In the general formula (I), A represents a trivalent aliphatic hydrocarbon group, aromatic hydrocarbon group or heteroaromatic hydrocarbon group which may have a substituent.
R ₁ represents the following general formula (II) or the following general formula (III).

In the general formula (II), R ₂ is a hydrogen atom, a halogen atom which may be substituted, an alkyl group, a cycloalkyl group, a halogen atom or an alkyl group, an aryl group, an alkoxy group, Represents an aryloxy group or —NR ₄ R ₅ ;

In the general formula (III), R ₃ is an alkenyl group, an alkynyl group, an aryl group optionally substituted with a halogen atom, an alkyl group or a cycloalkyl group, an aryl group optionally substituted with a halogen atom or an alkyl group, Represents an alkoxy group, an aryloxy group or —NR ₄ R ₅ ;

R ₄ and R ₅ in general formula (II) and general formula (III) represent an alkyl group or an aryl group. -* Represents a bond with an oxygen atom.

Hereinafter, the general formulas (I) to (III) will be described more specifically.
In the general formula (I), examples of the trivalent aliphatic hydrocarbon group represented by A include alkanes, alkenes, and alkynes having 3 or more acyclic or cyclic carbon atoms (for example, propane, propylene, propyne). , Butane, butene, butadiene, pentane, hexane, heptane, cyclohexane, hexene, hexyne, etc.). Of these, trivalent groups derived from alkanes having 3 to 6 carbon atoms are preferred.

Examples of the trivalent aromatic hydrocarbon group include benzene ring, biphenyl, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m- Terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, indene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, anthraanthrene ring And trivalent groups derived from a ring, tetralin and the like. Of these, a trivalent group derived from a benzene ring is preferable.

Examples of the trivalent aromatic heterocyclic group include a furan ring, a dibenzofuran ring, a thiophene ring, a dibenzothiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, and a benzimidazole ring. , Oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, cinnoline ring, quinoline ring, isoquinoline ring , A trivalent group derived from a phthalazine ring, a naphthyridine ring, a carbazole ring, a carboline ring, a diazacarbazole ring, or the like. Of these, a trivalent group derived from a pyridine ring is preferable.

R ₁ represents the general formula (II) or the general formula (III).
With respect to R ₂ in the general formula (II), the alkyl group is preferably an alkyl group having 1 to 15 carbon atoms, particularly 1 to 6 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, or butyl. Group, t-butyl group, pentyl group, hexyl group and the like, and more preferred are methyl group, ethyl group and t-butyl group. As the cycloalkyl group, a cyclopentyl group and a cyclohexyl group are preferable.
Examples of the aryl group include the same groups as the aromatic hydrocarbon group represented by A in the general formula (I), but a benzene ring group (phenyl group) is preferable.
As the alkoxy group, an alkoxy group having 1 to 6 carbon atoms is preferable, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a t-butoxy group, a pentyloxy group, a hexyloxy group, and the like. Are a methoxy group and an ethoxy group.
Examples of the aryloxy group include a phenoxy group and a naphthyloxy group. -NR _{4 R 4} and _{R 5} in R _5, wherein at Formula same groups as the alkyl group and the aryl group represented by _{R 2} in (II) and the like, alkyl groups having 1 to 6 carbon atoms Are preferable, and a methyl group and an ethyl group are more preferable. R ₄ and R ₅ may be linked together with a nitrogen atom to form a ring.
Examples of the halogen atom as a substituent include a chlorine atom, a bromine atom, and a fluorine atom. Of these, fluorine atoms are preferred.

As for R ₃ in the general formula (III), preferred examples of the alkenyl group include a vinyl group and an allyl group.
Preferred examples of the alkynyl group include an ethynyl group.
Note that the alkyl group, cycloalkyl group, aryl group, alkoxy group, aryloxy group, —NR ₄ R ₅ and halogen atom in the general formula (III) are the same specific examples as in the general formula (II). Can be mentioned.

The compound having the structure represented by the general formula (I) is preferably a compound having a structure represented by the following general formula (IV).

In the general formula (IV), R ₆ represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group, aryl group or alkoxy group. Preferably, it represents a hydrogen atom or an alkyl group, more preferably a hydrogen atom.
In the general formula (IV), _{R 1} has the same meaning as _{R 1} in the general formula (I).

In the present invention, in the general formula (I), R ₁ is represented by the general formula (II), and in the general formula (II), R ₂ is an alkyl group having 1 to 6 carbon atoms or a carbon number It preferably represents a 1 to 6 fluorinated alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms.
In the general formula (I), R ₁ is represented by the general formula (III), and in the general formula (III), R ₃ is an alkyl group having 1 to 6 carbon atoms or a group having 1 to 6 carbon atoms. It preferably represents a fluorinated alkyl group.

<Exemplary compounds having a structure represented by the general formula (I)>
Illustrative compounds having the structure represented by the general formula (I) are shown below. These exemplary compounds are examples, and the present invention is not limited thereto.

<Synthesis Example of Compound having Structure Represented by General Formula (I)>
(Acetylation)

1,3-bis (vinylsulfonyl) propan-2-ol (20 g, 0.083 mol) and acetonitrile (50 mL) were stirred at 40 ° C. in a nitrogen atmosphere. After confirming that the raw material had dissolved, 46 g (0.6 mol) of acetyl chloride was added dropwise little by little. After stirring for 4 hours, 20 mL of water was added and stirred for 30 minutes. This reaction solution was extracted twice with 20 mL of dichloromethane and concentrated under reduced pressure. Acetonitrile 100mL was added to this, and it heated and melt | dissolved at 60 degreeC. Activated carbon 0.2g was added to this solution, and it stirred for 20 minutes. The filtrate was allowed to stand at 10 ° C. overnight, and the precipitated crystals were washed twice with 20 mL of cold acetonitrile to obtain 13 g (yield 51%) of an acetyl compound (Exemplary Compound 1).
¹ H-NMR (400 MHz, DMSO-D6) δ 6.93 (dd, J = 16.5, 10.1 Hz, 2H), 6.17-6.28 (m, 4H), 5.48-5.54 (m, 1H), 3.66 (q, J = 7.8 Hz, 2H), 3.56 (dd, J = 15.1, 3.7 Hz, 2H), 1.92 (s, 3H)

(Benzoylation)

1,3-bis (vinylsulfonyl) propan-2-ol, 20 g (0.083 mol), 9.8 g (0.12 mol) of pyridine, and acetonitrile (60 mL) were stirred at 5 ° C. in a nitrogen atmosphere. To this mixture, 18 g (0.12 mol) of benzoyl chloride was added little by little, and after dropping, the temperature was slowly returned to room temperature. Since the raw materials remained after stirring for 30 hours, 1.3 g (0.016 mol) of pyridine and 2.3 g (0.017 mol) of benzoyl chloride were added and stirred for 6 hours, and 20 mL of water was added to this reaction solution and stirred for 30 minutes. did. The mixture was extracted twice with 20 mL of ethyl acetate and concentrated under reduced pressure. This was purified by recrystallization (ethyl acetate / methanol = 1/9) to obtain 10 g (35% yield) of benzoyl compound (Exemplary Compound 5).
¹ H-NMR (400 MHz, DMSO-D6) δ 7.91 (d, J = 7.3 Hz, 2H), 7.65 (t, J = 7.1 Hz, 1H), 7.51 (t, J = 7.8 Hz, 2H), 6.96 (dd, J = 16.5, 10.1 Hz, 2H), 6.13-6.19 (m, 4H),
5.75-5.81 (m, 1H), 3.86 (q, J = 7.8 Hz, 2H), 3.71 (dd, J = 15.1, 3.7 Hz, 2H)

[Lithium ion battery electrolyte]
The electrolyte solution for lithium ion batteries of the present invention (hereinafter also referred to as “non-aqueous electrolyte solution” or “electrolyte solution”) contains a vinyl sulfone compound having a structure represented by the above general formula (I). Features.
The non-aqueous electrolytic solution of the present invention is a non-aqueous electrolytic solution in which a lithium salt, the vinyl sulfone compound, and other compounds as required are dissolved in a non-aqueous solvent. Further, an organic polymer compound or the like may be added to the nonaqueous electrolytic solution to form a gel, rubber, or solid sheet.

The said vinyl sulfone compound contained in the non-aqueous electrolyte solution of this invention may be used independently, or may use 2 or more types together.
The content of the vinyl sulfone compound contained in the non-aqueous electrolyte solution of the present invention is preferably in the range of 0.01 to 5.0% by mass with respect to the whole electrolyte solution, 0.1 to 2. More preferably, it is in the range of 0% by mass. When the content is in the range of 0.1 to 2.0% by mass, it is possible to effectively improve the capacity reduction after the high-temperature storage test of the lithium ion battery.

The non-aqueous solvent used in the non-aqueous electrolyte solution of the present invention is not particularly limited, and a known non-aqueous solvent can be used.
For example, chain carbonates such as diethyl carbonate, dimethyl carbonate and ethyl methyl carbonate; cyclic carbonates such as ethylene carbonate, propylene carbonate and butylene carbonate; chain ethers such as 1,2-dimethoxyethane; tetrahydrofuran, 2-methyl Examples include cyclic ethers such as tetrahydrofuran, sulfolane, and 1,3-dioxolane; chain esters such as methyl formate, methyl acetate, and methyl propionate; and cyclic esters such as γ-butyrolactone and γ-valerolactone.

The non-aqueous solvent may be used alone or in combination of two or more. In the case of a mixed solvent, a combination of a mixed solvent containing a cyclic carbonate and a chain carbonate is preferable from the balance of conductivity and viscosity, and the cyclic carbonate is preferably ethylene carbonate.

The lithium salt used in the non-aqueous electrolyte of the present invention is not particularly limited, and a known lithium salt can be used.
For example, halides such as LiCl and LiBr; perhalogenates such as LiClO ₄ , LiBrO ₄ and LiClO ₄ ; inorganic lithium salts such as inorganic fluoride salts such as LiPF ₆ , LiBF ₄ and LiAsF ₆ ; LiCF ₃ SO ₃ , Examples include perfluoroalkane sulfonates such as LiC ₄ F ₉ SO ₃ ; fluorine-containing organic lithium salts such as perfluoroalkane sulfonic acid imide salts such as Li trifluoromethanesulfonyl imide ((CF ₃ SO ₂ ) ₂ NLi), and the like. . Of these, LiClO ₄ , LiPF ₆ , and LiBF ₄ are preferable.

Lithium salts may be used alone or in combination of two or more. The concentration of the lithium salt in the non-aqueous electrolyte can be in the range of 0.5 to 2.0 mol / L.

When the organic polymer compound is included in the above non-aqueous electrolyte solution and used in the form of a gel, rubber, or solid sheet, specific examples of the organic polymer compound include polyethylene oxide and polypropylene oxide. Polyether polymer compounds; Cross-linked polymers of polyether polymer compounds; Vinyl alcohol polymer compounds such as polyvinyl alcohol and polyvinyl butyral; Insolubilized vinyl alcohol polymer compounds; Polyepichlorohydrin; Polyphosphazene; Siloxane; vinyl polymer compounds such as polyvinylpyrrolidone, polyvinylidene carbonate, polyacrylonitrile; poly (ω-methoxyoligooxyethylene methacrylate), poly (ω-methoxyoligooxyethylene methacrylate) -co-methyl methacrylate And polymer copolymers such as poly (hexafluoropropylene-vinylidene fluoride).

The nonaqueous electrolytic solution of the present invention may further contain a film forming agent.
Specific examples of the film forming agent include carbonate compounds such as vinylene carbonate, vinylethyl carbonate, and methylphenyl carbonate; alkene sulfides such as ethylene sulfide and propylene sulfide; and sultone compounds such as 1,3-propane sultone and 1,4-butane sultone. And acid anhydrides such as maleic acid anhydride and succinic acid anhydride.

The non-aqueous electrolyte may further contain an overcharge inhibitor such as diphenyl ether or cyclohexyl benzene.
When using the above-mentioned various additives, the total content of the additives is the total amount of the non-aqueous electrolyte so as not to adversely affect other battery characteristics such as an increase in initial irreversible capacity, low temperature characteristics, and deterioration in rate characteristics. In general, it can be 10% by mass or less, in particular, 8% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

Further, as the electrolyte, a polymer solid electrolyte which is a conductor of an alkali metal cation such as lithium ion can be used.
Examples of the polymer solid electrolyte include those obtained by dissolving a Li salt in the aforementioned polyether polymer compound, and polymers in which the terminal hydroxy group of the polyether is substituted with an alkoxide.

<Preparation of electrolyte>
The nonaqueous electrolytic solution of the present invention can be prepared by dissolving a sulfone compound having a structure represented by the above general formula (I), an electrolyte, and, if necessary, other compounds in a nonaqueous solvent. .
In the preparation of the non-aqueous electrolyte solution, each raw material is preferably dehydrated in advance in order to reduce the water content when the electrolyte solution is used. Usually, it is good to dehydrate to 50 ppm or less, preferably 30 ppm or less, particularly preferably 10 ppm or less. Moreover, you may implement dehydration, a deoxidation process, etc. after electrolyte solution preparation.

[Lithium ion battery]
The lithium ion battery of the present invention can take various configurations, but the basic configuration is an embodiment including a positive electrode and a negative electrode capable of inserting and extracting lithium ions, and the above-described electrolyte solution of the present invention. Usually, it is obtained by housing the positive electrode and the negative electrode in a case through a porous film impregnated with an electrolytic solution.
The lithium ion battery of the present invention is characterized in that the electrolytic solution contains a vinyl sulfone compound.
The shape of the lithium ion battery of the present invention is not particularly limited, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

<Negative electrode>
The negative electrode according to the present invention can take various forms. Basically, the negative electrode includes a current collector and an active material layer formed on the current collector, and the active material layer includes a negative electrode active material. It is preferable that it contains. The active material layer preferably further contains a binder.

(Negative electrode current collector)
It does not specifically limit as a negative electrode collector which concerns on this invention, A well-known thing can be used. Specific examples include metal thin films such as rolled copper foil, electrolytic copper foil, and stainless steel foil.
The thickness of the negative electrode current collector can be in the range of 4 to 30 μm. Preferably, it is in the range of 6 to 20 μm.

(Negative electrode active material)
The negative electrode active material is not particularly limited as long as it can occlude and release lithium ions. Specific examples thereof include carbonaceous materials, alloy-based materials, lithium-containing metal composite oxide materials, and the like.
These negative electrode active materials may be used alone or in combination of two or more. Of these, preferred are carbonaceous materials and alloy-based materials, and more preferred are carbonaceous materials.
Among the carbonaceous materials, amorphous carbon materials, graphite, and those in which the surface of graphite is coated with amorphous carbon compared to graphite are preferred, and in particular, the surface of graphite or graphite is amorphous compared to graphite. Those coated with carbon are generally preferred because of their high energy density.
Among these negative electrode active materials containing carbonaceous materials, they contain at least one atom selected from the group consisting of Si atoms, Sn atoms, and Pb atoms because they have a large capacity per unit mass when made into batteries. A carbonaceous material active material is more preferable.

The graphite preferably has a lattice plane (002 plane) d value (interlayer distance) of 0.335 to 0.338 nm, particularly 0.335 to 0.337 nm, as determined by X-ray diffraction using the Gakushin method. The crystallite size (Lc) determined by X-ray diffraction by the Gakushin method is usually 10 nm or more, preferably 50 nm or more, and particularly preferably 100 nm or more.
The ash content is usually 1% by mass or less, preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less.

The graphite surface coated with amorphous carbon is preferably graphite having a d-value of 0.335 to 0.338 nm on the lattice plane (002 plane) in X-ray diffraction as a core material. A carbonaceous material having a larger d-value on the lattice plane (002 plane) in X-ray diffraction than the core material is attached, and the d-value on the lattice plane (002 plane) in X-ray diffraction is greater than that of the core material and the core material The ratio with respect to the carbonaceous material having a large is 99/1 to 80/20 in mass ratio. When this is used, a negative electrode having a high capacity and hardly reacting with the electrolytic solution can be produced.

The particle size of the carbonaceous material is in the range of 1 to 100 μm, preferably 3 to 50 μm, more preferably 5 to 40 μm in terms of median diameter by laser diffraction / scattering method.
BET specific surface area of the carbonaceous material, 0.3 ~ 25.0m ² / g, preferably in the range of 0.8 ~ 10.0m ² / g.

Further, the carbonaceous material is analyzed by Raman spectrum using argon ion laser light, the peak P in the peak intensity of the peak _{P A} in the range of 1570 ~ 1620 cm ^-1 in the range of _I A, 1300 ~ _1400cm ^-1 _When the peak intensity of _B is I _B , the R value (= I _B / I _A ) represented by the ratio of I _B and I _A is preferably in the range of 0.01 to 0.7. Further, the half width of the peak in the range of 1570 ~ 1620cm ^-1, 26cm ^-1 or less, are preferred in particular 25 cm ^-1 or less.

The alloy material is not particularly limited as long as it can occlude and release lithium, and single metals and alloys that form lithium alloys, or oxides, carbides, nitrides, silicides, sulfides, and phosphides thereof. Any of these compounds may be used. Preferably, it is a material including a single metal and an alloy forming a lithium alloy, more preferably a material including a group 13 and group 14 metal / metalloid element (that is, excluding carbon), and further, aluminum, silicon, and It is preferably a single metal of tin (hereinafter, these may be referred to as “specific metal elements”), and an alloy or compound containing these elements.

Examples of the negative electrode active material having at least one element selected from the specific metal elements include a single metal of any one specific metal element, an alloy composed of two or more specific metal elements, one type, or two or more types An alloy composed of the specific metal element and one or more other metal elements, a compound containing one or more specific metal elements, and oxides, carbides, nitrides of the compounds, Examples include complex compounds such as silicides, sulfides, and phosphides.
By using these simple metals, alloys or metal compounds as the negative electrode active material, the capacity of the battery can be increased.

In addition, compounds in which these complex compounds are complexly bonded to several kinds of elements such as simple metals, alloys, or non-metallic elements can be given as examples. More specifically, for example, in silicon and tin, an alloy of these elements and a metal that does not operate as a negative electrode can be used. In addition, for example, in the case of tin, a complex compound containing 5 to 6 kinds of elements in combination with a metal that acts as a negative electrode other than tin and silicon, a metal that does not operate as a negative electrode, and a nonmetallic element is also used. Can do.

Among these negative electrode active materials, since the capacity per unit mass is large when a battery is formed, any one simple metal of a specific metal element, an alloy of two or more specific metal elements, oxidation of a specific metal element A material, carbide, nitride or the like is preferable, and silicon and / or tin metal alone, an alloy, an oxide, carbide, nitride, or the like is particularly preferable because of its large capacity per unit mass.
In addition, although the capacity per unit mass is inferior to that of using a single metal or an alloy, the following compounds containing silicon and / or tin are also preferred because of excellent cycle characteristics.

Silicon and / or silicon and / or tin to oxygen in the range of 0.5 to 1.5, preferably 0.7 to 1.3, more preferably 0.9 to 1.1 Or tin oxide.
Silicon and / or silicon and / or tin and nitrogen in the range of 0.5 to 1.5, preferably 0.7 to 1.3, more preferably 0.9 to 1.1 / Or tin nitride.
Silicon and / or tin having an element ratio of silicon and / or tin to carbon of 0.5 to 1.5, preferably 0.7 to 1.3, more preferably 0.9 to 1.1 Carbides.

These alloy materials may be in the form of powder or thin film, and may be crystalline or amorphous.
The average particle size of the alloy-based material is not particularly limited in order to exhibit the effects of the present invention, but is in the range of 0.1 to 50 μm, preferably 1 to 20 μm, particularly preferably 2 to 10 μm. This is for preventing electrode expansion and preventing cycle characteristics from deteriorating. Moreover, it is for fully expressing performance, such as current collection and a capacity | capacitance.

The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium. However, a lithium-titanium composite oxide (hereinafter referred to as “lithium-titanium composite oxide”) is not limited. Is preferred).
In addition, a part of lithium or titanium in the lithium titanium composite oxide is selected from the group consisting of other metal elements such as Na, K, Co, Al, Fe, Mg, Cr, Ga, Cu, Zn, and Nb. Those substituted with at least one element are also preferred.

Furthermore, it is a lithium titanium composite oxide represented by Li _x Ti _y M _z O ₄ , and 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, and 0 ≦ z ≦ 1.6. It is preferable that the structure at the time of occlusion / release of lithium ions is stable (M is a group consisting of Na, K, Co, Al, Fe, Mg, Cr, Ga, Cu, Zn, and Nb). Represents at least one element selected).
In particular, the structure in which x, y, and z of the lithium titanium composite oxide represented by Li _x Ti _y M _z O ₄ satisfy any of the following (a) to (c) This is particularly preferable because of a good balance.

(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
A particularly preferred representative composition is Li _4/3 Ti _5/3 O ₄ in (a), Li ₁ Ti ₂ O ₄ in (b), and Li _4/5 Ti _11/5 O ₄ in (c). .
As for the structure when Z ≠ 0, for example, Li _4/3 Ti _4/3 Al _1/3 O ₄ is preferable.
In the present invention, a negative electrode active material disclosed in JP-A-2015-173107 can also be used.

(Negative electrode binder)
Although it does not specifically limit as a binder for negative electrodes, The thing which has an olefinically unsaturated bond in a molecule | numerator is preferable. Specific examples include styrene-butadiene rubber, styrene / isoprene / styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, and ethylene / propylene / diene copolymer.

By using such a binder having an olefinically unsaturated bond, the swellability of the active material layer with respect to the electrolytic solution can be reduced. Of these, styrene-butadiene rubber is preferred because of its availability.
By using a binder having an olefinically unsaturated bond in the molecule and a negative electrode active material in combination, the mechanical strength of the negative electrode plate can be increased. When the mechanical strength of the negative electrode plate is high, deterioration of the negative electrode due to charge / discharge is suppressed, and the cycle life can be extended.

The binder having an olefinically unsaturated bond in the molecule preferably has a high molecular weight and / or a high proportion of unsaturated bonds.
As the molecular weight of the binder, the weight average molecular weight can be usually 10,000 or more, and can usually be 1,000,000 or less. If it is this range, both mechanical strength and flexibility can be controlled to a favorable range. The weight average molecular weight is preferably 50,000 or more, and preferably 300,000 or less.

As the ratio of olefinically unsaturated bonds in the binder molecule, the number of moles of olefinically unsaturated bonds per gram of the total binder is usually within the range of 2.5 × 10 ⁻⁷ to 5 × 10 ⁻⁶ mol. Can do. If it is this range, the intensity | strength improvement effect is fully acquired and flexibility is also favorable.

For the binder having an olefinically unsaturated bond, the degree of unsaturation can usually be in the range of 15 to 90%. The degree of unsaturation is preferably in the range of 20-80%. In the present specification, the degree of unsaturation represents the ratio (%) of the double bond to the repeating unit of the polymer.
As the binder, a binder having no olefinically unsaturated bond can also be used. By using in combination a binder having an olefinically unsaturated bond and a binder having no olefinically unsaturated bond in the molecule, improvement in coatability and the like can be expected.

When the binder having an olefinically unsaturated bond is 100% by mass, the mixing ratio of the binder having no olefinically unsaturated bond is usually 150% by mass or less in order to suppress a decrease in the strength of the active material layer. Preferably, it is 120 mass% or less.

Examples of binders having no olefinically unsaturated bond include thickening polysaccharides such as methylcellulose, carboxymethylcellulose, starch, carrageenan, pullulan, guar gum, xanthan gum (xanthan gum); polyethers such as polyethylene oxide and polypropylene oxide; Vinyl alcohols such as polyvinyl alcohol and polyvinyl butyral; polyacids such as polyacrylic acid and polymethacrylic acid or metal salts thereof; fluorine-containing polymers such as polyvinylidene fluoride; alkane polymers such as polyethylene and polypropylene; Examples include coalescence.

(Negative conductive auxiliary)
The active material layer may contain a conductive additive in order to improve the conductivity of the negative electrode.
The conductive aid is not particularly limited, and examples thereof include carbon black such as acetylene black, ketjen black, and furnace black, fine powder made of Cu, Ni having an average particle size of 1 μm or less, or an alloy thereof.
It is preferable that the addition amount of a conductive support agent is 10 mass% or less with respect to a negative electrode active material.

The negative electrode according to the present invention can be formed by dispersing a negative electrode active material and optionally a binder and / or a conductive aid in a dispersion medium to form a slurry, which is applied to a current collector and dried. As the dispersion medium, an organic solvent such as alcohol or water can be used.
It does not specifically limit as a collector which apply | coats a slurry, A well-known thing can be used. Specific examples include metal thin films such as rolled copper foil, electrolytic copper foil, and stainless steel foil.

The thickness of the negative electrode active material layer (hereinafter sometimes simply referred to as “active material layer”) obtained by applying and drying the slurry is sufficient for practical use as a negative electrode and sufficient lithium ions for high-density current values. From the point of the function of occlusion / release, it can be in the range of 5 to 200 μm. Preferably, it is in the range of 20 to 100 μm.

You may adjust the thickness of an active material layer so that it may become the thickness of the said range by pressing after application | coating of a slurry and drying.
Although the density of the negative electrode active material in the active material layer varies depending on the application, it is within the range of 1.10 to 1.65 g / cm ³ in applications in which input / output characteristics such as in-vehicle applications and power tool applications are important. It is preferable.

Within this range, it is possible to avoid an increase in contact resistance between particles due to the density being too low, and it is also possible to suppress a decrease in rate characteristics due to the density being too high.
On the other hand, in applications in which capacity is important, such as mobile device applications such as mobile phones and personal computers, it is usually preferable to be within the range of 1.45 to 1.90 g / cm ³ .

Within this range, it is possible to avoid a decrease in battery capacity per unit volume due to the density being too low, and it is also possible to suppress a decrease in rate characteristics due to the density being too high.

<Positive electrode>
The positive electrode according to the present invention can take various forms, but basically includes a current collector and an active material layer formed on the current collector, and the active material layer comprises a positive electrode active material. It is preferable that it contains. The active material layer preferably further contains a binder.

(Positive electrode current collector)
It does not specifically limit as a positive electrode electrical power collector which concerns on this invention, A well-known thing can be used. Specific examples include aluminum, nickel, and stainless steel (SUS).
The thickness of the positive electrode current collector can be in the range of 4 to 30 μm. Preferably, it is in the range of 6 to 20 μm.

(Positive electrode active material)
The positive electrode active material is not particularly limited as long as it can occlude and release lithium ions during charge and discharge. A substance containing lithium and at least one transition metal is preferable, and examples thereof include a lithium transition metal composite oxide and a lithium-containing transition metal phosphate compound.

V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferable as the transition metal of the lithium transition metal composite oxide. Specific examples include lithium-cobalt composite oxides such as LiCoO ₂ and LiNiO ₂ . Lithium / nickel composite oxide, lithium / manganese composite oxide such as LiMnO ₂ , LiMn ₂ O ₄ , Li ₂ MnO _3, etc., and some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are Al, Ti , V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, and those substituted with other metals such as Si.
Among the substituted ones, LiNi _1-ab Mn _a Co _b O ₂ (a and b represent numbers of 0 or more and less than 1 except for the case where a and b are both 0), LiNi _{1-c -d-e Co c Al d Mg} e O 2 (c, d, e each represents a number from 0 to less than 1, except in the case of c, d, e are both 0), more LiNi _{1- ab} Mn _a Co _b O ₂ (0 ≦ a <0.4, 0 ≦ b <0.4), LiNi _1- cDe Co _c Al _d Mg _e O ₂ (0 ≦ c <0. 3, 0 ≦ d <0.1, 0 ≦ e <0.05), particularly LiNi _1/3 Co _01/3 Mn _1/3 O ₂ , LiNi _0.5 Co _0.3 Mn _0.2 O _{2, LiNi 0.5 Mn 0.5 O 2} , LiNi 0.85 Co 0.10 Al 0.05 O 2, LiNi 0.85 o _0.10 Al _0.03 Mg _0.02 O ₂ is preferred.

As the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu and the like are preferable, and specific examples include, for example, LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ). ₃ , iron phosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are Al, Ti, V, Cr, Mn , Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si and the like substituted with other metals.

These positive electrode active materials may be used alone or in combination.
In addition, a material in which a substance (surface adhering substance) having a composition different from that of the substance constituting the main cathode active material is attached to the surface of the cathode active material can be used. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

The amount of the surface adhering substance is not particularly limited in order to exhibit the effect of the present invention, but is preferably within the range of 0.1 to 20 ppm by mass, more preferably 1 to Used within the range of 10 ppm. The surface adhering substance can suppress the oxidation reaction of the non-aqueous electrolyte on the surface of the positive electrode active material, and can improve the battery life.

(Positive electrode conductive aid)
The positive electrode active material layer may contain a conductive additive in order to improve the conductivity of the positive electrode. The conductive aid is not particularly limited, and examples thereof include carbon powders such as acetylene black, carbon black, and graphite, various metal fibers, powders, and foils.

(Positive electrode binder)
The binder for the positive electrode is not particularly limited, and a known binder can be arbitrarily selected and used. Examples include inorganic compounds such as silicate and water glass, and resins having no unsaturated bond such as Teflon (registered trademark) and polyvinylidene fluoride. Among them, a resin having no unsaturated bond is preferable because it is difficult to decompose during the oxidation reaction.
The weight average molecular weight of the binder can usually be in the range of 10,000 to 3,000,000, preferably in the range of 100,000 to 1,000,000.

<Others>
In addition to the various materials described above, the electrode may contain a thickener, a conductive material, a filler, etc. in order to increase mechanical strength and electrical conductivity.
Examples of the thickener include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein.

(Production method of electrode)
The electrode may be produced by a conventional method. For example, it can be formed by adding a binder, a thickener, a conductive material, a solvent, or the like to a negative electrode or a positive electrode active material to form a slurry, applying this to a current collector, drying it, and then pressing it.
In addition, a material obtained by adding a binder or a conductive material to an active material as it is is formed into a sheet electrode, formed into a pellet electrode by compression molding, or deposited on the current collector by a method such as vapor deposition, sputtering, or plating. A thin film can also be formed.

When graphite is used as the negative electrode active material, the density of the negative electrode active material layer after drying and pressing is preferably in the range of 1.0 to 2.2 g / cm ³ . Preferably, it is within the range of 1.3 to 1.9 g / cm ³ . This is for preventing the increase in initial irreversible capacity due to the destruction of the negative electrode active material particles, preventing the electrolyte from penetrating into the active material layer from being deteriorated, and deteriorating the high rate charge / discharge characteristics. Moreover, it is for preventing the capacity | capacitance per unit volume falling by the electroconductivity between active materials falling.
The density after drying and pressing of the positive electrode active material layer is preferably in the range of 1.5 to 5.0 g / cm ³ . More preferably, it is in the range of 2.2 to 4.0 g / cm ³ . This is to prevent deterioration of the high rate charge / discharge characteristics due to a decrease in the permeability of the electrolytic solution into the active material layer. Moreover, it is for preventing the deterioration of the high rate charge / discharge characteristic by the electrical conductivity between active materials falling.

<Separator, exterior body>
A porous film (separator) is interposed between the positive electrode and the negative electrode to prevent a short circuit. In this case, the electrolytic solution is used by impregnating the porous membrane. The material and shape of the porous film are not particularly limited as long as it is stable to the electrolytic solution and excellent in liquid retention, and a porous sheet or nonwoven fabric made of a polyolefin such as polyethylene or polypropylene is preferable.
The material of the battery case used in the lithium ion battery of the present invention is also arbitrary, and nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, a laminate film, or the like is used.
The operating voltage of the above-described lithium ion battery of the present invention is usually in the range of 2 to 6V.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

[Example 1]: Storage stability in solution (ethylene carbonate) <Preparation of solution 1>
The above exemplified compound 1 (5 g) was dissolved in ethylene carbonate (100 mL), and then the solution was filtered with activated carbon to obtain an ethylene carbonate solution of exemplified compound 1. This solution was stored in the dark at 25 ° C. for 30 days, and then the presence or absence of precipitates was visually confirmed. The evaluation results are shown in Table I below. In the table, no precipitate is indicated by ◯, and the presence of precipitate is indicated by ×.

<Preparation of solutions 2 to 17>
Solutions 2 to 17 were prepared in the same manner except that Exemplified Compound 1 used in the preparation of Solution 1 was changed to the exemplified compounds shown in Table I below, and the presence or absence of precipitates was confirmed.

<Preparation of Solution 18>
A solution 18 was prepared in the same manner except that the exemplified compound 1 used in the preparation of the solution 1 was changed to the following comparative compound 1, and the presence or absence of precipitates was confirmed.

From the results shown in Table I, it is recognized that the solution containing the vinyl sulfone compound of the present invention has no precipitate and is excellent in storage stability.

[Example 2]: Storage stability (capacity) of a battery
<Preparation of non-aqueous electrolyte solution>
In a dry argon atmosphere, 0.05% by mass of the exemplified compound 1 and 2% by mass of vinylene carbonate were mixed in a mixed solvent of ethylene carbonate and ethyl methyl carbonate (mass ratio 3: 7). Next, fully dried LiPF ₆ was dissolved at a rate of 1 mol / liter to obtain a non-aqueous electrolyte.

<Preparation of positive electrode>
An N-methylpyrrolidone solution containing 94% by mass of lithium-cobalt composite oxide (LiCoO ₂ ) as a positive electrode active material, 3% by mass of acetylene black as a conductive additive, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder The slurry was mixed with a disperser. This was uniformly applied on both sides of a 15 μm thick aluminum foil, dried, and then pressed so that the density of the positive electrode active material layer was 3.1 g / cm ³ to produce a positive electrode.

<Production of negative electrode>
Artificial graphite powder KS-44 (trade name, manufactured by Timcal Co., Ltd.) as a negative electrode active material in 98 parts by mass, an aqueous dispersion of carboxymethylcellulose sodium (concentration of 1% by mass of carboxymethylcellulose sodium) as a thickener and a binder, respectively, 100 mass And 2 parts by mass of an aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber 50% by mass) were added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a 10 μm thick copper foil, dried, and then pressed so that the density of the negative electrode active material was 1.6 g / cm ³ to prepare a negative electrode.

<Production of lithium ion battery 1>
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the positive electrode, the separator, the negative electrode, the separator, and the positive electrode to produce a battery element. This battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and then the non-aqueous electrolyte was poured into the bag. Then, vacuum sealing was performed to produce a sheet-like lithium ion battery 1.
The sheet-like lithium ion battery 1 was used for the evaluation shown below, and the evaluation results are shown in Table II below.

<Initial discharge capacity evaluation test>
The sheet-like lithium ion battery produced above was charged to 4.1 V with a constant current corresponding to 0.2 C at 25 ° C., and then discharged to 3 V with a constant current of 0.2 C. This was performed for 3 cycles to stabilize the battery. Next, after charging to 4.2V with a constant current of 0.7C, charging is performed until the current value becomes 0.05C with a constant voltage of 4.2V, and discharging to 3V with a constant current of 0.2C, The initial discharge capacity was determined.
Here, 1C represents a current value for discharging the reference capacity of the battery in one hour, and for example, 0.2C represents a current value of 1/5 thereof.

<High temperature storage characteristics evaluation test>
After completion of the initial discharge capacity evaluation test, the lithium ion battery was charged to 4.2 V at a constant current of 0.7 C at 25 ° C., and then charged to a current value of 0.05 C at a constant voltage of 4.2 V. Then, it preserve | saved at 85 degreeC for 1 day.
After cooling the lithium ion battery to 25 ° C., it was discharged to 3 V at a constant current of 0.2 C at 25 ° C., and the remaining capacity after the high temperature storage characteristics evaluation test was measured. The remaining capacity after storage was calculated as a percentage (%).
Remaining capacity = (discharge capacity after storage / initial discharge capacity) x 100 (%)

<Preparation of lithium ion battery 2>
In the production of the lithium ion battery 1, the same manner as the lithium ion battery 1 except that the content of the exemplified compound 1 contained in the non-aqueous electrolyte solution was changed to 0.5% by mass instead of 0.05% by mass. A lithium ion battery 2 was produced and evaluated in the same manner as the lithium ion battery 1.

<Production of lithium ion battery 3>
In the production of the lithium ion battery 1, the same manner as the lithium ion battery 1 except that the content of the exemplified compound 1 contained in the non-aqueous electrolyte solution was changed to 1.0% by mass instead of 0.05% by mass. A lithium ion battery 3 was produced and evaluated in the same manner as the lithium ion battery 1.

<Production of lithium ion batteries 4 to 19>
Lithium ion batteries 4 to 19 were produced in the same manner as the lithium ion battery 3, except that the exemplified compound 1 was changed as shown in Table II below in the production of the lithium ion battery 3, and the same as the lithium ion battery 3. Was evaluated.

<Preparation of lithium ion battery 20>
In the production of the lithium ion battery 3, the lithium ion battery 20 was produced in the same manner as the lithium ion battery 3 except that the exemplified compound 1 was replaced with the comparative compound 1 and evaluated in the same manner as the lithium ion battery 3.

From the results shown in Table II, it is recognized that the lithium ion battery produced using the vinyl sulfone compound of the present invention has an increased residual capacity after high temperature storage and improved high temperature storage characteristics.

[Example 3]: Cycle test <Preparation of non-aqueous electrolyte solution 1>
1 mass% of the exemplified compound 1 was mixed in a mixed solvent (mass ratio 1: 1) of ethylene carbonate (EC) and diethyl carbonate (DEC) in a dry argon atmosphere. Next, fully dried LiPF ₆ was dissolved at a rate of 1 mol / liter to obtain a non-aqueous electrolyte.

<Preparation of non-aqueous electrolyte solution 2>
In a dry argon atmosphere, 1% by mass of the exemplified compound 1 was mixed in a mixed solvent (mass ratio 1: 1: 1) of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC). Next, fully dried LiPF ₆ was dissolved at a rate of 1 mol / liter to obtain a non-aqueous electrolyte.

<Preparation of positive electrode 1>
93% by mass of lithium nickel cobalt manganese composite oxide (ternary highNi type-LiNi _5/10 Co _2/10 Mn _3/10 O ₂ ) manufactured by Nichia Chemical, and acetylene black 3 as a conductive additive % By mass and 3% by mass of polyvinylidene fluoride (PVdF) as a binder were mixed in a N-methylpyrrolidone solution with a disperser to form a slurry. This thickness 15μm uniformly coated on the both surfaces of an aluminum foil, dried, the density of the positive electrode active material layer to prepare a positive electrode was pressed to be 3.1 g / cm ^3.

<Preparation of negative electrode 1>
As a negative electrode active material, 93 parts by mass of artificial graphite powder KS-44 (trade name, manufactured by Timcal) was mixed with 8 parts by mass of PVdF, and N-methylpyrrolidone was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a 10 μm thick copper foil, dried, and then pressed so that the density of the negative electrode active material was 1.6 g / cm ³ to prepare a negative electrode.

<Preparation of negative electrode 2>
As a negative electrode active material, 91 parts by mass of SiO-containing artificial graphite powder (manufactured by Nippon Carbon Co., Ltd.) and 9 parts by mass of PVdF were mixed, and N-methylpyrrolidone was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a 10 μm thick copper foil, dried, and then pressed so that the density of the negative electrode active material was 1.6 g / cm ³ to prepare a negative electrode.

<Production of lithium ion battery 21>
The positive electrode 1, the negative electrode 1, and a polyethylene separator were laminated in the order of the positive electrode, the separator, the negative electrode, the separator, and the positive electrode to prepare a battery element. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and the non-aqueous electrolyte 1 was injected into the bag. Then, vacuum sealing was performed to produce a sheet-like lithium ion battery 1.
Using this sheet-like lithium ion battery 21, the following evaluation was performed, and the evaluation results are shown in Table III below.

<Cycle evaluation test>
The sheet-like lithium ion battery prepared above was charged at a constant current-constant voltage (hereinafter referred to as “CCCV charge” as appropriate) at 0.2 C at 25 ° C. and then discharged to 3.0 V at 0.2 C. The charging / discharging cycle was repeated 100 times. The cut-off current during charging was 0.01C. The capacity retention rate after 300 cycles was determined by the following calculation formula, and the cycle characteristics were evaluated using the calculated value. The larger this value is, the less the cycle deterioration of the battery is. Moreover, the open circuit voltage between battery terminals was measured at the end of the first charge.
Capacity maintenance rate after 300 cycles [%]
= 100th discharge capacity [mAh / g] / 1st discharge capacity [mAh / g] × 100

<Preparation of lithium ion battery 22>
Lithium ion batteries 21 were prepared in the same manner as the lithium ion battery 21 except that the content of the exemplified compound 1 contained in the non-aqueous electrolyte solution was changed to 0.01% by mass instead of 1% by mass. A battery 22 was produced and evaluated in the same manner as the lithium ion battery 21.

<Preparation of lithium ion battery 23>
Lithium ion batteries 21 were prepared in the same manner as the lithium ion battery 21 except that the content of the exemplified compound 1 contained in the non-aqueous electrolyte solution was changed to 4.95% by mass instead of 1% by mass. A battery 23 was produced and evaluated in the same manner as the lithium ion battery 21.

<Preparation of Lithium Ion Battery 24>
A lithium ion battery 24 was produced in the same manner as the lithium ion battery 21 except that the negative electrode 1 was replaced with the negative electrode 2 in the production of the lithium ion battery 21, and the same evaluation as the lithium ion battery 21 was performed.

<Preparation of lithium ion battery 25>
A lithium ion battery 25 was produced in the same manner as the lithium ion battery 21 except that the nonaqueous electrolyte solution 1 was replaced with the nonaqueous electrolyte solution 2 in the production of the lithium ion battery 21. Was evaluated.

<Production of lithium ion batteries 26 to 28>
In the production of the lithium ion battery 21, lithium ion batteries 26 to 28 were produced in the same manner as the lithium ion battery 21, except that the exemplified compound 1 contained in the non-aqueous electrolyte was replaced with a compound corresponding to each of the following Table III. The same evaluation as that of the lithium ion battery 21 was performed.

<Production of lithium ion batteries 29-31>
In the production of the lithium ion battery 21, lithium ion batteries 29 to 31 were produced in the same manner as the lithium ion battery 21, except that the exemplified compound 1 contained in the nonaqueous electrolytic solution was replaced with a compound corresponding to Table III below. The same evaluation as that of the lithium ion battery 21 was performed.

<Preparation of lithium ion battery 32>
Lithium ion batteries 21 were prepared in the same manner as the lithium ion battery 21 except that the content of the exemplified compound 1 contained in the non-aqueous electrolyte solution was changed to 0.05% by mass instead of 1% by mass. A battery 32 was produced and evaluated in the same manner as the lithium ion battery 21.

<Preparation of lithium ion battery 33>
In the production of the lithium ion battery 21, the lithium ion battery 33 is the same as the lithium ion battery 21 except that the content of the exemplary compound 1 contained in the non-aqueous electrolyte is 6 mass% instead of 1 mass%. The same evaluation as that of the lithium ion battery 21 was performed.

From the results shown in Table III, it is recognized that the cycle characteristics of the lithium ion battery produced using the vinyl sulfone compound of the present invention are improved. Further, as can be seen from a comparison between the battery 21 and the battery 24 using the vinyl sulfone compound of the present invention, the use of a negative electrode active material made of a carbonaceous material containing Si atoms as the negative electrode material increases the battery capacity. It was confirmed that it is more preferable in obtaining the effect of improving the cycle characteristics of the invention.

[Example 4]: Initial charge / discharge efficiency test <Initial charge / discharge efficiency test>
The sheet-like lithium ion battery produced as described above was charged to 4.2 V at 25 ° C., discharged to 3 V, and conditioned until the capacity was stabilized. Thereafter, the battery was charged to 4.2 V at a current value of 1.2 mA at 25 ° C., and discharged to 3 V, and an initial charge / discharge efficiency test was performed. At this time, when the initial discharge capacity is (i), the second discharge capacity is (ii), the initial charge capacity is (iii), and the second charge capacity is (iv), ((i) + (ii )) / ((Iii) + (iv)) × 100 was determined as “initial charge / discharge efficiency”.
A lithium ion battery having the same configuration as that of the cycle test was prepared, and the initial charge / discharge efficiency was calculated.
The evaluation results are shown in Table IV.

From the results shown in Table IV, it is recognized that the lithium ion battery produced using the vinyl sulfone compound of the present invention also improves the initial charge / discharge efficiency.

The present invention provides a vinyl sulfone compound that is excellent in storage stability when stored in a non-aqueous solvent for a long period of time, and that can improve a decrease in capacity after a high-temperature storage test when used in a lithium ion battery. Can be used.

Claims (16)

1. A vinyl sulfone compound having a structure represented by the following general formula (I).
   

   

   [In General Formula (I), A represents a trivalent aliphatic hydrocarbon group, aromatic hydrocarbon group or heteroaromatic hydrocarbon group which may have a substituent. R ₁ represents the following general formula (II) or the following general formula (III). ]
   

   

   [In the general formula (II), R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, a halogen atom or an alkyl group, an aryl group, an alkoxy group. Represents an aryloxy group or —NR ₄ R ₅ . R ₄ and R ₅ represent an alkyl group or an aryl group. -* Represents a bond with an oxygen atom.
   In the general formula (III), R ₃ is an alkenyl group, an alkynyl group, an aryl group optionally substituted with a halogen atom, an alkyl group or a cycloalkyl group, an aryl group optionally substituted with a halogen atom or an alkyl group, Represents an alkoxy group, an aryloxy group or —NR ₄ R ₅ ; R ₄ and R ₅ represent an alkyl group or an aryl group. -* Represents a bond with an oxygen atom. ]
2. The vinyl sulfone compound according to claim 1, wherein the compound having a structure represented by the general formula (I) is a compound having a structure represented by the following general formula (IV).
   

   

   [In General Formula (IV), R ₆ represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group, aryl group or alkoxy group. R ₁ has the same meaning as _{R 1} in the general formula (I). ]
3. The vinyl sulfone compound according to claim 2, wherein R _{6 of the} compound having a structure represented by the general formula (IV) is a hydrogen atom.
4. In the general formula (I), R ₁ is represented by the general formula (II),
   The vinyl according to any one of claims 1 to 3, wherein, in the general formula (II), R ₂ represents an alkyl group having 1 to 6 carbon atoms or a fluorinated alkyl group having 1 to 6 carbon atoms. Sulfone compounds.
5. In the general formula (I), R ₁ is represented by the general formula (II),
   The vinyl sulfone compound according to any one of claims 1 to 4, wherein, in the general formula (II), R ₂ is an alkyl group having 1 to 3 carbon atoms.
6. In the general formula (I), R ₁ is represented by the general formula (III),
   The vinyl according to any one of claims 1 to ₃ , wherein, in the general formula (III), R ₃ represents an alkyl group having 1 to 6 carbon atoms or a fluorinated alkyl group having 1 to 6 carbon atoms. Sulfone compounds.
7. The vinylsulfone compound according to any one of claims 1 to 6, wherein the compound having a structure represented by the general formula (I) is a material added to an electrolyte for a lithium ion battery.
8. An electrolyte solution for a lithium ion battery containing the vinyl sulfone compound according to any one of claims 1 to 7.
9. The electrolyte solution for a lithium ion battery according to claim 8, comprising at least one kind of chain carbonate or cyclic carbonate.
10. 10. The electrolyte for a lithium ion battery according to claim 8, wherein the content of the vinyl sulfone compound is in the range of 0.01 to 5.0% by mass with respect to the total amount of the electrolyte.
11. A lithium ion battery containing the vinyl sulfone compound according to any one of claims 1 to 7 in an electrolytic solution.
12. The lithium ion battery according to claim 11, comprising a negative electrode made of an active material containing natural graphite or artificial graphite which is a carbonaceous material.
13. The lithium ion battery according to claim 11 or 12, comprising a negative electrode made of a carbonaceous material active material containing at least one atom selected from the group consisting of Si atom, Sn atom and Pb atom.
14. The lithium ion battery according to claim 13, comprising a negative electrode made of a carbonaceous material active material containing Si atoms.
15. The lithium ion battery according to any one of claims 11 to 14, comprising a positive electrode made of an active material containing any one of a lithium transition metal composite oxide or a lithium-containing transition metal phosphate compound.
16. The lithium ion battery according to claim 15, comprising a positive electrode made of an active material containing a lithium transition metal composite oxide.