JP5542827B2 - Non-aqueous electrolyte for lithium secondary battery containing unsaturated sultone compound, additive for lithium secondary battery, and lithium secondary battery - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is useful as a non-aqueous electrolyte solution for lithium secondary batteries having excellent output characteristics (hereinafter sometimes simply referred to as “non-aqueous electrolyte solution”) , a lithium secondary battery using the same, and an additive for the electrolyte solution. The present invention relates to an additive for a lithium secondary battery.

In recent years, lithium secondary batteries have been widely used as electronic devices such as mobile phones and laptop computers, electric vehicles, and power storage power sources. In particular, recently, there has been a rapid increase in demand for batteries with high capacity, high output, and high energy density that can be mounted on hybrid vehicles and electric vehicles.
The lithium secondary battery is mainly composed of a positive electrode and a negative electrode containing a material capable of inserting and extracting lithium, and a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent.
As the positive electrode active material used for the positive electrode, for example, lithium metal oxides such as LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , and LiFePO ₄ are used.
In addition, as the non-aqueous electrolyte, a mixed solvent of carbonates such as ethylene carbonate, propylene carbonate, ethylene carbonate, methyl carbonate, LiPF ₆ , LiBF ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) A solution in which a Li electrolyte such as ₂ is mixed is used.
On the other hand, negative electrode active materials used for negative electrodes include metal lithium, metal compounds capable of occluding and releasing lithium (metal simple substance, oxide, alloy with lithium, etc.) and carbon materials, particularly lithium. Lithium secondary batteries using coke, artificial graphite, and natural graphite that can be occluded and released have been put into practical use.

Among battery performances, especially for lithium secondary batteries for automobiles, high output is demanded. Therefore, it is desired to reduce battery resistance under various conditions.
As one of the factors that increase the resistance of a battery, a film formed by a decomposition product of a solvent or an inorganic salt formed on the negative electrode surface is known. In general, it is known that a reductive decomposition reaction of an electrolytic solution occurs on the negative electrode surface because lithium metal is present in the negative electrode active material under charging conditions. If such reductive decomposition occurs continuously, the resistance of the battery increases, the charge / discharge efficiency decreases, and the energy density of the battery decreases. In order to overcome these problems, attempts have been made to add various compounds to the electrolytic solution.
Attempts have been made to improve the storage stability and resistance of batteries by containing vinylene carbonate (VC) as an attempt (for example, see JP-A-5-13088), but it is still not sufficient.
In addition, a nonaqueous electrolytic solution using an unsaturated sultone compound as an additive is described (for example, see JP-A-2002-329528).

The present invention has been made to meet the above-mentioned problems, and an object of the present invention is to provide a non-aqueous electrolytic solution that improves battery output characteristics by keeping the resistance value of the battery low, and the non-aqueous electrolytic solution. And providing a lithium secondary battery with improved resistance.
A further object of the present invention is to provide an additive for a lithium secondary battery useful for such a non-aqueous electrolyte.

As a result of intensive studies on the above problems, the present inventor has suppressed the increase in battery resistance by adding a specific additive to the non-aqueous electrolyte of the lithium secondary battery, and such A novel compound was found as an additive, and the present invention was completed.
That is, the present invention is as follows.
<1> A lithium secondary containing an unsaturated sultone compound having a substituent containing a silicon atom, wherein the unsaturated sultone compound having a substituent containing a silicon atom is a compound represented by the following general formula (1) Non-aqueous electrolyte for batteries .

[In the general formula (1), ^{R 1} represents -SiR ⁵ R ⁶ R ^7, each ^R 2, ^{R 3} and ^{R 4} are independently, water atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, to display the alkynyl group or a haloalkyl group having 1 to 10 carbon atoms, from 2 to 10 carbon atoms. R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or Represents a phenyl group. m represents 1 . ]

<2> In the general formula (1), R ² , R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a carbon number. A alkynyl group having 2 to 6 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms, and R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, The nonaqueous electrolytic solution for a lithium secondary battery according to <1>, which is an alkynyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a phenyl group.
<3> In the general formula (1), R ² , R ³ and R ⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, an ethyl group, a vinyl group, a propenyl group, a propargyl group, or The nonaqueous electrolytic solution for a lithium secondary battery according to <2>, which is a trifluoromethyl group.
<4> The unsaturated sultone compound having a substituent containing a silicon atom is 3-trimethylsilyl-5H-1,2-oxathiol-2,2-dioxide, 3- (dimethyl-t-butylsilyl) -5H-1. , 2-oxathiol-2,2-dioxide, 3-triisopropylsilyl-5H-1,2-oxathiol-2,2-dioxide is at least one selected from the group consisting of <1> Nonaqueous electrolyte for lithium secondary battery .
<5> Furthermore, the non-aqueous electrolyte for lithium secondary batteries of any one of <1>-<4> containing the compound represented by the following general formula (2).

[In General Formula (2), R ⁸ and R ⁹ each independently represent a hydrogen atom, a methyl group, an ethyl group, or a propyl group. ]

<6> The nonaqueous electrolyte solution for a lithium secondary battery according to any one of <1> to <5>, further comprising a compound represented by the following general formula (3).

[In General Formula (3), X ¹ , X ² , X ³ and X ⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl having 1 to 3 carbon atoms which may be substituted with a fluorine atom. Indicates a group. However, X ^{1 to} X ⁴ are not simultaneously hydrogen atoms. ]

<7> The content of the compound represented by the general formula (1) is 0.001% by mass to 10% by mass with respect to the total mass of the nonaqueous electrolytic solution for a lithium secondary battery. > The nonaqueous electrolyte for lithium secondary batteries of any one of>.
<8> The content of the compound represented by the general formula (2) is 0.001% by mass to 10% by mass with respect to the total mass of the nonaqueous electrolytic solution for a lithium secondary battery. <5> to <7 > The nonaqueous electrolyte for lithium secondary batteries of any one of>.
<9> The content of the compound represented by the general formula (3) is 0.001% by mass to 10% by mass with respect to the total mass of the nonaqueous electrolytic solution for a lithium secondary battery. > The nonaqueous electrolyte for lithium secondary batteries of any one of>.
<10> An additive for a lithium secondary battery represented by the following general formula (1).

[In the general formula (1), ^{R 1} represents -SiR ⁵ R ⁶ R ^7, each ^R 2, ^{R 3} and ^{R 4} are independently, water atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, to display the alkynyl group or a haloalkyl group having 1 to 10 carbon atoms, from 2 to 10 carbon atoms. R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or Represents a phenyl group. m represents 1 . ]

<11> Selected from positive electrode and metal lithium, lithium-containing alloy, metal or alloy capable of alloying with lithium, oxide capable of doping / de-doping lithium ion, doped material of lithium ion, or a mixture thereof The lithium secondary battery containing the negative electrode which contains at least 1 sort (s) as a negative electrode active material, and the non-aqueous electrolyte for lithium secondary batteries of any one of <1>-<9>.
<12> Selected from positive electrode and metal lithium, lithium-containing alloy, metal or alloy capable of alloying with lithium, oxide capable of doping / de-doping lithium ion, lithium ion doping material, or a mixture thereof A lithium secondary battery , comprising: a negative electrode containing at least one selected from the above as a negative electrode active material; and the nonaqueous electrolyte for a lithium secondary battery according to any one of <1> to <9>. Lithium secondary battery obtained by letting

According to the present invention, a nonaqueous electrolytic solution used for a lithium secondary battery, which can suppress the resistance value of the battery and realize high output of the battery, and the resistance value using the nonaqueous electrolytic solution Thus, it is possible to provide a high-power lithium secondary battery improved.
Further, according to the present invention, it is possible to provide an additive for a useful lithium secondary battery in such a non-aqueous electrolyte solution.

It is typical sectional drawing of the coin-type battery which shows an example of the lithium secondary battery of this invention.

  The unsaturated sultone compound of the present invention, a nonaqueous electrolytic solution using the same, and a lithium secondary battery using the nonaqueous electrolytic solution will be specifically described.

[Unsaturated sultone compound having a substituent containing a silicon atom]
The nonaqueous electrolytic solution of the present invention contains an unsaturated sultone compound having a substituent containing a silicon atom. The unsaturated sultone compound having a substituent containing a silicon atom used in the nonaqueous electrolytic solution of the present invention is a sultone compound having an unsaturated bond and a substituent containing a silicon atom (silicon atom) in the molecule. Can be used without any particular restrictions.
The substituent containing a silicon atom may be directly bonded to the unsaturated sultone skeleton, or may be bonded to the unsaturated sultone skeleton via a linking group. Examples of the linking group between the substituent containing a silicon atom and the unsaturated sultone skeleton include an oxygen atom, a nitrogen atom, a sulfur atom, and an alkylene group.
The substituent containing a silicon atom is preferably a —SiR ⁵ R ⁶ R ⁷ group. As the unsaturated sultone compound, a compound in which the —SiR ⁵ R ⁶ R ⁷ group is directly bonded to the unsaturated sultone skeleton is preferable. Here, R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an alkoxy having 1 to 6 carbon atoms. Represents a group or a phenyl group.
Although the number of the substituents containing the silicon atom which the unsaturated sultone compound of this invention has is also arbitrary, it is preferable to contain in the range of 1-4, More preferably, it is the range of 1-2.

The unsaturated sultone compound having a substituent containing a silicon atom is preferably a compound represented by the following general formula (1).
The compound represented by the following general formula (1) is useful as an additive for a lithium secondary battery.

In general formula (1), R ¹ , R ² , R ³ and R ⁴ are each independently —SiR ⁵ R ⁶ R ⁷ , a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or 2 to 2 carbon atoms. 10 represents an alkenyl group, an alkynyl group having 2 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms, and at least one of R ¹ , R ² , R ^3, and R ⁴ is —SiR ⁵ R ⁶ R ⁷ . is there.
Here, R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an alkoxy having 1 to 6 carbon atoms. Represents a group or a phenyl group.
m represents 1, 2 or 3. When m represents 2 or 3, a plurality of R ³ and R ⁴ may be the same or different from each other.

In the general formula (1), examples of the “halogen atom” include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
In the general formula (1), the “alkyl group having 1 to 10 carbon atoms” is a linear or branched alkyl group having 1 to 10 carbon atoms, methyl, ethyl, propyl, isopropyl, butyl, isobutyl. Specific examples include, sec-butyl, tert-butyl, pentyl, 2-methylbutyl, 1-methylpentyl, neopentyl, 1-ethylpropyl, hexyl, 3,3-dimethylbutyl, heptyl, octyl, nonyl and decyl.
In the general formula (1), the “alkenyl group having 2 to 10 carbon atoms” is a linear or branched alkenyl group having 2 to 10 carbon atoms, vinyl, allyl, butenyl, buten-3-yl. Specific examples include pentenyl, penten-4-yl, hexenyl, hexen-4-yl, hexen-5-yl, heptenyl, octenyl, nonenyl and decenyl.
In the general formula (1), the “alkynyl group having 2 to 10 carbon atoms” is a linear or branched alkynyl group having 2 to 10 carbon atoms, and includes ethynyl, propargyl, butyn-4-yl, butyne -3-yl, pentynyl, pentyn-4-yl, hexyn-4-yl, hexyn-5-yl, heptin-7-yl, octin-8-yl, nonin-9-yl, decyn-10-yl A specific example is given.

In the general formula (1), the “haloalkyl group having 1 to 10 carbon atoms” is a linear or branched alkenyl group having 1 to 10 carbon atoms, such as fluoromethyl, difluoromethyl, trifluoromethyl, 2 , 2,2-trifluoroethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl, perfluorooctyl, perfluorononyl, perfluorodecyl, perfluoroisopropyl, perfluorohexyl Specific examples include fluoroisobutyl, chloromethyl, chloroethyl, chloropropyl, bromomethyl, bromoethyl, bromopropyl, methyl iodide, ethyl iodide, and propyl iodide.
In the general formula (1), the “C 1-6 alkoxy group” is a linear or branched alkoxy group having 1 to 6 carbon atoms, and includes methoxy, ethoxy, propoxy, isopropyloxy, butoxy, tert Specific examples include butoxy, pentyloxy, and hexyloxy.

Note that at least one of R ¹ , R ² , R ^3, and R ⁴ represents —SiR ⁵ R ⁶ R ⁷ , where R ⁵ , R ^6, and R ⁷ each independently represent 1 to 10 represents an alkyl group, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. R ⁵ , R ⁶ and R ⁷ are preferably an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, Or a phenyl group is mentioned, A C1-C4 alkyl group, a C2-C4 alkenyl group, a C2-C4 alkynyl group, a C1-C3 alkoxy group, or a phenyl group is more preferable.
Specific examples of —SiR ⁵ R ⁶ R ⁷ include trialkylsilyl groups such as trimethylsilyl group, triethylsilyl group, triisopropylsilyl group, dimethyl-t-butylsilyl group, trimethoxysilyl group, and triethoxysilyl group. Silyl groups having an alkynyl group such as trialkoxysilyl group, dimethylvinylsilyl group, methyldivinylsilyl group, dimethylallylsilyl group, dimethylethynylsilyl group, dimethylpropargylsilyl group, dimethylphenylsilyl Silyl groups having a phenyl group such as a methyldiphenylsilyl group and a triphenylsilyl group, and the like, preferably a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a dimethyl-t-butylsilyl group, a trimethyl group. These are toxisilyl group, triethoxysilyl group, and dimethylphenylsilyl group.
At least one of the substituents in the general formula (1) represents —SiR ⁵ R ⁶ R ⁷ , but one or two of R ¹ , R ² , R ³ and R ⁴ are —SiR ⁵ R. it is preferably a ⁶ R ^7.

R ¹ in the general formula (1) is preferably —SiR ⁵ R ⁶ R ⁷ , a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 2 carbon atoms. -10 alkynyl group or haloalkyl group having 1 to 10 carbon atoms, wherein R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms and 2 to 10 carbon atoms. An alkenyl group, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group.
R ¹ in the general formula (1) is more preferably —SiR ⁵ R ⁶ R ⁷ , a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. , An alkynyl group having 2 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms, wherein R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 6 carbon atoms and a carbon number They are a 2-6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 alkoxy group, or a phenyl group.
R ¹ in the general formula (1) is particularly preferably —SiR ⁵ R ⁶ R ⁷ , where R ⁵ , R ⁶ and R ⁷ are each independently a methyl group, an ethyl group, or a propyl group. Group, isopropyl group, vinyl group, methoxy group, ethoxy group or phenyl group.

R ² in the general formula (1) is preferably —SiR ⁵ R ⁶ R ⁷ , a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 2 carbon atoms. -10 alkynyl group or haloalkyl group having 1 to 10 carbon atoms, wherein R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms and 2 to 10 carbon atoms. An alkenyl group, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group.
R ² in the general formula (1) is more preferably —SiR ⁵ R ⁶ R ⁷ , a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. , An alkynyl group having 2 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms, wherein R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 6 carbon atoms and a carbon number They are a 2-6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 alkoxy group, or a phenyl group.
R ² in the general formula (1) particularly preferably represents a hydrogen atom, a fluorine atom, a methyl group, or —SiR ⁵ R ⁶ R ⁷ , wherein R ⁵ , R ⁶ , and R ⁷ are each independently A methyl group, an ethyl group, a propyl group, an isopropyl group, a vinyl group, a methoxy group, an ethoxy group, or a phenyl group.

As R ³ and R ⁴ in the general formula (1), preferably —SiR ⁵ R ⁶ R ⁷ , a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, An alkynyl group having 2 to 10 carbon atoms or a haloalkyl group having 1 to 10 carbon atoms, wherein R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms and 2 to 2 carbon atoms. It is a 10 alkenyl group, a C2-C10 alkynyl group, a C1-C6 alkoxy group, or a phenyl group.
More preferably, R ³ and R ⁴ in the general formula (1) are —SiR ⁵ R ⁶ R ⁷ , a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 2 to 6 carbon atoms. Represents an alkenyl group having 2 to 6 carbon atoms, or a haloalkyl group having 1 to 6 carbon atoms, wherein R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 6 carbon atoms. , An alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group.
R ³ and R ⁴ in the general formula (1) particularly preferably represent a hydrogen atom, a fluorine atom, a methyl group, or —SiR ⁵ R ⁶ R ⁷ , where R ⁵ , R ⁶ , R ⁷ Are each independently a methyl, ethyl, propyl, isopropyl, vinyl, methoxy, ethoxy or phenyl group.

  In the general formula (1), m is 1, 2 or 3, preferably 1 or 2, and more preferably 1.

In addition, from the viewpoint of more effectively obtaining the effects of the present invention, as the form of the general formula (1), R ¹ is —SiR ⁵ R ⁶ R ⁷ , and R ² , R ^3, and R ⁴ are respectively Independently, it is a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms (more preferably R ² , R ³ and R ⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, an ethyl group, a vinyl group, a propenyl group, a propargyl group, or a trifluoromethyl group), and m is 1 or 2, and R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 4 carbon atoms, or 1 to 2 carbon atoms. 4 alkoxy groups, Others are also suitable form a phenyl group.

Further, as the form of the general formula (1), R ¹ is a hydrogen atom, R ² is a trimethylsilyl group, R ³ is a methyl group, R ⁴ is a methyl group, m It is also preferable that it is a form other than the form which is the combination which is 1.

Specific examples [Exemplary Compound 1 to Exemplified Compound 33] of the compound represented by the general formula (1) in the present invention are described in the following table by clearly indicating each substituent in the general formula (1). The invention is not limited to these compounds.
In the structures of the following exemplary compounds, “Me” represents a methyl group, “Et” represents an ethyl group, “Pr” represents a propyl group, “iso-Pr” represents an isopropyl group, “Bu” represents a butyl group, “ “tBu” represents a tertiary butyl group, “Ph” represents a phenyl group, “vinyl” represents a vinyl group, and “allyl” represents an allyl group.
In the following exemplified compounds, m is 2 or 3, and R ³ and R ⁴ are all the same and represent a hydrogen atom.

As the compound represented by the general formula (1), a compound represented by the following general formula (1b) having —SiR ⁵ R ⁶ R ⁷ at the position of R ^{1 in} the compound is more preferable.
The compound represented by the following general formula (1b) is useful as an additive for a lithium secondary battery.

In the general formula (1b), R ² , R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 2 to 10 carbon atoms. An alkynyl group or a haloalkyl group having 1 to 10 carbon atoms. R ⁵ , R ⁶ , and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, Or represents a phenyl group. m is 1 or 2, and when m represents 2, a plurality of R ³ and R ⁴ may be the same or different from each other.

R ² , R ³ and R ⁴ in the general formula (1b) are synonymous with R ² , R ³ and R ⁴ in the general formula (1) except that they are not —SiR ⁵ R ⁶ R ⁷ . A preferred range of ^R 2, ^{R 3} and ^{R 4} in the general formula (1b) is also the preferred ranges of ^R 2, ^{R 3} and ^{R 4} in the general formula (1) except that it is not a -SiR ⁵ R ⁶ R ⁷ It is the same.
Also, ^R 5, ^{R 6} and ^{R 7} in the general formula (1b) has the same meaning as ^R 5, ^{R 6} and ^{R 7} in the general formula (1), and preferred ranges are also the same.

  The unsaturated sultone compound represented by the general formula (1) or (1b) can be produced, for example, by the method described below, but is not limited to this production method.

The said manufacturing method is demonstrated.
The unsaturated sultone compound represented by the general formula (1) or (1b) is obtained by treating the unsaturated sultone compound represented by the general formula (1a) with a base in the presence of a solvent. It can manufacture by making it react with the silyl compound represented.
In the general formula (1a), (1b), and general formula ^(4), R 2 to R ⁷ have the same meanings as ^R 2 to R ⁷ in the general formula (1) or (1b), X is a halogen atom Or a trifluoromethanesulfonyloxy group;
The base is not particularly limited as long as it has a deprotonating ability for the substrate. For example, metal hydrides such as sodium hydride and potassium hydride; sodium methoxide, sodium ethoxide and potassium tert-butoxide. Metal alkoxides; or organic metals such as methyl lithium, butyl lithium, methyl magnesium bromide, lithium diisopropylamide, and lithium bistrimethylsilylamide, and the like, preferably metal hydrides or organic bases. More preferred are lithium diisopropylamide and lithium bistrimethylsilylamide.

The solvent used in the reaction is not particularly limited as long as it does not inhibit the reaction and dissolves the starting materials to some extent. For example, ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran and dioxane; benzene, toluene, Aromatic hydrocarbons such as xylene and chlorobenzene; aliphatic hydrocarbons such as hexane, cyclohexane and heptane or a mixed solvent thereof may be mentioned, and ethers, aliphatic hydrocarbons or aromatics are preferable. Hydrocarbons, more preferably tetrahydrofuran or toluene.
The amount of the solvent is usually 1.0 to 20 liters and preferably 1.0 to 10 liters with respect to 1 mol of the compound (1a).
The reaction temperature varies depending on the raw material compound, the reaction reagent, the solvent, and the like, but can usually be carried out in the range of -90 ° C to the reflux temperature in the reaction system, and is preferably -70 to 0 ° C.
While the reaction time varies depending on the raw material compound, reaction reagent, solvent, reaction temperature and the like, it can usually be carried out in the range of 6 minutes to 48 hours, preferably 10 minutes to 24 hours.
Compound (1a) used in this step is a commercially available product or is produced by a known method. For example, it is manufactured according to the description of Synlett, 2002, 2019-2022; Heterocycles, 1982, 19, 2247-2250.
In the general formula (1) of the present invention, the compound in which R ^{2 to} R ⁴ are silyl groups is produced, for example, by the method described in Journal of Organometallic Chemistry, 1977, 141, 23-34.
An unsaturated sultone compound having a silicon atom as a substituent, represented by the compound represented by the general formula (1) or the general formula (1b), is a lithium secondary battery additive, particularly a lithium secondary battery described later. This additive is useful as an additive for non-aqueous electrolytes, and by adding this additive to the non-aqueous electrolyte, an increase in the resistance of the battery over time can be suppressed and high output can be realized.

<Non-aqueous electrolyte>
The nonaqueous electrolytic solution of the present invention is characterized by containing an unsaturated sultone compound having a substituent containing a silicon atom, and other components can be optionally included.
The unsaturated sultone compound contained in the nonaqueous electrolytic solution of the present invention may be only one type or two or more types may be used in combination.
The content of the unsaturated sultone compound contained in the nonaqueous electrolytic solution of the present invention is preferably 0.001% by mass to 10% by mass with respect to the total mass of the nonaqueous electrolytic solution, and 0.05% by mass to A range of 5% by mass is more preferable. In this range, it is possible to further suppress the increase in resistance of the battery over time and achieve further higher output.

Next, other components of the nonaqueous electrolytic solution will be described. The non-aqueous electrolyte generally contains a non-aqueous electrolyte and a non-aqueous solvent.
[Nonaqueous solvent]
Various known solvents can be appropriately selected as the non-aqueous solvent in the present invention, but it is preferable to use a cyclic aprotic solvent and / or a chain aprotic solvent.
In order to improve the safety of the battery, when aiming to improve the flash point of the solvent, it is preferable to use a cyclic aprotic solvent as the non-aqueous solvent.

[Cyclic aprotic solvent]
As the cyclic aprotic solvent, cyclic carbonate, cyclic carboxylic acid ester, cyclic sulfone, and cyclic ether can be used.
The cyclic aprotic solvent may be used alone or in combination of two or more.
The mixing ratio of the cyclic aprotic solvent in the non-aqueous solvent is 10% by mass to 100% by mass, more preferably 20% by mass to 90% by mass, and particularly preferably 30% by mass to 80% by mass. By setting it as such a ratio, the electroconductivity of the electrolyte solution relating to the charge / discharge characteristics of the battery can be increased.
Specific examples of the cyclic carbonate include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and the like. Of these, ethylene carbonate and propylene carbonate having a high dielectric constant are preferably used. In the case of a battery using graphite as the negative electrode active material, ethylene carbonate is more preferable. Moreover, you may use these cyclic carbonates in mixture of 2 or more types.

Specific examples of the cyclic carboxylic acid ester include γ-butyrolactone, δ-valerolactone, alkyl substitution products such as methyl γ-butyrolactone, ethyl γ-butyrolactone, and ethyl δ-valerolactone.
The cyclic carboxylic acid ester has a low vapor pressure, a low viscosity, a high dielectric constant, and can lower the viscosity of the electrolytic solution without lowering the flash point of the electrolytic solution and the degree of dissociation of the electrolyte. For this reason, since it has the feature that the conductivity of the electrolytic solution, which is an index related to the discharge characteristics of the battery, can be increased without increasing the flammability of the electrolytic solution, when aiming to improve the flash point of the solvent, It is preferable to use a cyclic carboxylic acid ester as the cyclic aprotic solvent. Of the cyclic carboxylic acid esters, γ-butyrolactone is most preferred.
The cyclic carboxylic acid ester is preferably used by mixing with another cyclic aprotic solvent. Examples thereof include a mixture of a cyclic carboxylic acid ester and a cyclic carbonate and / or a chain carbonate.

Specific examples of combinations of cyclic carboxylic acid esters and cyclic carbonates and / or chain carbonates include γ-butyrolactone and ethylene carbonate, γ-butyrolactone and ethylene carbonate and dimethyl carbonate, and γ-butyrolactone and ethylene carbonate and methylethyl. Carbonate, γ-butyrolactone and ethylene carbonate and diethyl carbonate, γ-butyrolactone and propylene carbonate, γ-butyrolactone and propylene carbonate and dimethyl carbonate, γ-butyrolactone and propylene carbonate and methyl ethyl carbonate, γ-butyrolactone and propylene carbonate and diethyl carbonate, γ-butyrolactone, ethylene carbonate and propylene carbonate, γ-butyrolactone Ethylene carbonate and propylene carbonate and dimethyl carbonate, γ-butyrolactone and ethylene carbonate and propylene carbonate and methyl ethyl carbonate, γ-butyrolactone and ethylene carbonate, propylene carbonate and diethyl carbonate, γ-butyrolactone, ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate, γ-butyrolactone, ethylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, ethylene carbonate, methyl ethyl carbonate, diethyl carbonate, γ-butyrolactone, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, γ-butyrolactone, ethylene carbonate And Pyrene carbonate, dimethyl carbonate and methyl ethyl carbonate, γ-butyrolactone, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, γ-butyrolactone, ethylene carbonate, propylene carbonate, methyl ethyl carbonate and diethyl carbonate, γ-butyrolactone and ethylene carbonate Propylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate, γ-butyrolactone and sulfolane, γ-butyrolactone and ethylene carbonate and sulfolane, γ-butyrolactone and propylene carbonate and sulfolane, γ-butyrolactone, ethylene carbonate, propylene carbonate and sulfolane, γ -Butyrolactone and Su Such Horan and dimethyl carbonate.
Examples of the cyclic sulfone include sulfolane, 2-methylsulfolane, 3-methylsulfolane, dimethyl sulfone, diethyl sulfone, dipropyl sulfone, methylethyl sulfone, methylpropyl sulfone and the like.
An example of a cyclic ether is dioxolane.

[Chain aprotic solvent]
As the chain aprotic solvent of the present invention, a chain carbonate, a chain carboxylic acid ester, a chain ether, a chain phosphate, or the like can be used.
The mixing ratio of the chain aprotic solvent in the non-aqueous solvent is 10% by mass to 100% by mass, more preferably 20% by mass to 90% by mass, and particularly preferably 30% by mass to 80% by mass.
Specific examples of the chain carbonate include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl propyl carbonate, dipropyl carbonate, methyl butyl carbonate, ethyl butyl carbonate, dibutyl carbonate, methyl pentyl carbonate, Examples include ethyl pentyl carbonate, dipentyl carbonate, methyl heptyl carbonate, ethyl heptyl carbonate, diheptyl carbonate, methyl hexyl carbonate, ethyl hexyl carbonate, dihexyl carbonate, methyl octyl carbonate, ethyl octyl carbonate, dioctyl carbonate, and methyltrifluoroethyl carbonate. These chain carbonates may be used as a mixture of two or more.

Specific examples of the chain carboxylic acid ester include methyl pivalate.
Specific examples of the chain ether include dimethoxyethane.
Specific examples of the chain phosphate ester include trimethyl phosphate.

[Combination of solvents]
The non-aqueous solvent used in the non-aqueous electrolyte solution according to the present invention may be used alone or in combination. Further, only one or a plurality of cyclic aprotic solvents may be used, or only one or a plurality of chain aprotic solvents may be used, or a cyclic aprotic solvent and a chain protic solvent. You may mix and use a solvent. When the load characteristics and low temperature characteristics of the battery are particularly intended to be improved, it is preferable to use a combination of a cyclic aprotic solvent and a chain aprotic solvent as the nonaqueous solvent.
Furthermore, in view of the electrochemical stability of the electrolytic solution, it is most preferable to apply a cyclic carbonate to the cyclic aprotic solvent and a chain carbonate to the chain aprotic solvent. Moreover, the conductivity of the electrolyte solution related to the charge / discharge characteristics of the battery can be increased by a combination of the cyclic carboxylic acid ester and the cyclic carbonate and / or the chain carbonate.

As a combination of cyclic carbonate and chain carbonate, specifically, ethylene carbonate and dimethyl carbonate, ethylene carbonate and methyl ethyl carbonate, ethylene carbonate and diethyl carbonate, propylene carbonate and dimethyl carbonate, propylene carbonate and methyl ethyl carbonate, propylene carbonate and Diethyl carbonate, ethylene carbonate and propylene carbonate and methyl ethyl carbonate, ethylene carbonate and propylene carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and methyl ethyl carbonate Diethyl carbonate, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate and methyl ethyl carbonate And diethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate.
The mixing ratio of the cyclic carbonate and the chain carbonate is expressed as a mass ratio, and the cyclic carbonate: chain carbonate is 5:95 to 80 to 20, more preferably 10:90 to 70:30, particularly preferably 15:85. ~ 55: 45. By setting it as such a ratio, since the raise of the viscosity of electrolyte solution can be suppressed and the dissociation degree of electrolyte can be raised, the conductivity of electrolyte solution in connection with the charge / discharge characteristic of a battery can be raised. In addition, the solubility of the electrolyte can be further increased. Therefore, since it can be set as the electrolyte solution excellent in the electrical conductivity in normal temperature or low temperature, the load characteristic of the battery from normal temperature to low temperature can be improved.

[Other solvents]
The nonaqueous electrolytic solution according to the present invention may contain a solvent other than the above as a nonaqueous solvent. Specific examples of the other solvent include amides such as dimethylformamide, chain carbamates such as methyl-N, N-dimethylcarbamate, cyclic amides such as N-methylpyrrolidone, N, N-dimethylimidazolidinone and the like. Examples thereof include boron compounds such as cyclic urea, trimethyl borate, triethyl borate, tributyl borate, trioctyl borate, trimethylsilyl borate, and polyethylene glycol derivatives represented by the following general formula.
HO (CH ₂ CH ₂ O) _a H
HO [CH ₂ CH (CH ₃ ) O] _b H
CH ₃ O (CH ₂ CH ₂ O) _c H
CH ₃ O [CH ₂ CH (CH ₃ ) O] _d H
CH ₃ O (CH ₂ CH ₂ O) _e CH ₃
CH ₃ O [CH ₂ CH (CH ₃ ) O] _f CH _{3
C 9 H 19 PHO (CH 2} CH 2 O) g [CH (CH 3) O] h CH 3
(Ph is a phenyl group)
CH ₃ O [CH ₂ CH (CH ₃ ) O] _i CO [OCH (CH ₃ ) CH ₂ ] _j OCH ₃
In the above formula, a to f are integers of 5 to 250, g to j are integers of 2 to 249, 5 ≦ g + h ≦ 250, and 5 ≦ i + j ≦ 250.

[Compound represented by formula (2)]
The nonaqueous electrolytic solution of the present invention can contain a compound represented by the general formula (2). The form in which the nonaqueous electrolytic solution of the present invention contains the compound represented by the general formula (2) is preferable in terms of forming a surface film on the negative electrode.

In the general formula (2), R ⁸ and R ⁹ each independently represent a hydrogen atom, a methyl group, an ethyl group, or a propyl group.
Examples of the compound represented by the general formula (2) include vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, propyl vinylene carbonate, dimethyl vinylene carbonate, diethyl vinylene carbonate, and dipropyl vinylene carbonate. Of these, vinylene carbonate is most preferred.
Although content of the compound represented by General formula (2) can be suitably selected according to the objective, 0.001 mass%-10 mass% are preferable with respect to nonaqueous electrolyte whole quantity, 0.05 mass% More preferably, it is -5 mass%.

[Compound represented by formula (3)]
The nonaqueous electrolytic solution of the present invention can contain a compound represented by the general formula (3). The form in which the nonaqueous electrolytic solution of the present invention contains a compound represented by the general formula (3) is preferable in terms of forming a surface film on the negative electrode.

In the general formula (3), X ¹ , X ² , X ³ and X ⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl having 1 to 3 carbon atoms which may be substituted with a fluorine atom. Indicates a group. However, X ^{1 to} X ⁴ are not simultaneously hydrogen atoms.
In the general formula (3), examples of the alkyl group having 1 to 3 carbon atoms which may be substituted by a fluorine atom represented by X ^{1 to} X ⁴ include, for example, fluoromethyl, difluoromethyl, trifluoromethyl, pentafluoroethyl, heptafluoro And propyl.
Known compounds can be used as the compound represented by the general formula (3). For example, 4-fluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4,4,5-tri Fluorinated ethylene carbonate in which 1 to 4 hydrogen atoms are substituted with fluorine in ethylene carbonate, such as fluoroethylene carbonate and 4,4,5,5-tetrafluoroethylene carbonate. Among these, 4,5-difluoroethylene carbonate and 4-fluoroethylene carbonate are most desirable.
Although content of the compound represented by General formula (3) can be suitably selected according to the objective, 0.001 mass%-10 mass% are preferable with respect to nonaqueous electrolyte whole quantity, 0.05 mass% More preferably, it is -5 mass%.

〔Electrolytes〕
Various known electrolytes can be used for the nonaqueous electrolytic solution of the present invention, and any of them can be used as long as it is normally used as an electrolyte for a nonaqueous electrolytic solution.
Specific examples of the electrolyte include (C ₂ H ₅ ) ₄ NPF ₆ , (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ) ₄ NAsF ₆ , (C ₂ H ₅ ) ₄ N ₂ SiF ₆ , (C ₂ H ₅ ) ₄ NOSO ₂ C _k F _{(2k + 1)} (k = 1 to 8), (C ₂ H ₅ ) ₄ NPF _n [C _k F _{(2k + 1)} ] _(6-n) Tetraalkylammonium salts such as (n = 1 to 5, k = 1 to 8), LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , Li ₂ SiF ₆ , LiOSO ₂ C _k F Lithium salts such as _{(2k + 1)} (k = 1 to 8), LiPF _n [C _k F _{(2k + 1)} ] _(6-n) (n = 1 to 5, k = 1 to 8) are included. . Moreover, the lithium salt represented by the following general formula can also be used.

LiC (SO ₂ R ⁷ ) (SO ₂ R ⁸ ) (SO ₂ R ⁹ ), LiN (SO ₂ OR ¹⁰ ) (SO ₂ OR ¹¹ ), LiN (SO ₂ R ¹² ) (SO ₂ R ¹³ ) (where R ^{7 to} R ¹³ may be the same as or different from each other, and are a C 1-8 perfluoroalkyl group). These electrolytes may be used alone or in combination of two or more.
Of these, lithium salts are particularly desirable, and LiPF ₆ , LiBF ₄ , LiOSO ₂ C _k F _{(2k + 1)} (k = 1 to 8), LiClO ₄ , LiAsF ₆ , LiNSO ₂ [C _k F _{( 2k + 1)] 2 (k} = 1~8 _{integer), LiPF n [C k F} (2k + 1)] (6-n) (n = 1~5, k = 1~8 integer) are preferred.
The electrolyte in the present invention is usually preferably contained in the nonaqueous electrolyte at a concentration of 0.1 mol / liter to 3 mol / liter, preferably 0.5 mol / liter to 2 mol / liter.

In the nonaqueous electrolytic solution of the present invention, when a cyclic carboxylic acid ester such as γ-butyrolactone is used in combination as the nonaqueous solvent, it is particularly desirable to contain LiPF ₆ . Since LiPF ₆ has a high degree of dissociation, the conductivity of the electrolytic solution can be increased, and the reductive decomposition reaction of the electrolytic solution on the negative electrode can be suppressed. LiPF ₆ may be used alone, or LiPF ₆ and other electrolytes may be used. Any other electrolyte can be used as long as it is normally used as an electrolyte for a non-aqueous electrolyte, but lithium salts other than LiPF ₆ are preferred among the specific examples of the lithium salts described above. .
Specific examples include LiPF ₆ and LiBF ₄ , LiPF ₆ and LiN [SO ₂ C _k F _{(2k + 1)} ] ₂ (k = 1 to 8), LiPF ₆ , LiBF ₄ and LiN [SO ₂ C _k F _{( 2k + 1)} ] (k = 1 to 8).

The ratio of LiPF _{6 in} the lithium salt is 1% by mass to 100% by mass, preferably 10% by mass to 100% by mass, and more preferably 50% by mass to 100% by mass. Such an electrolyte is preferably contained in the non-aqueous electrolyte at a concentration of 0.1 mol / liter to 3 mol / liter, preferably 0.5 mol / liter to 2 mol / liter.
The non-aqueous electrolyte of the present invention is not only suitable as a non-aqueous electrolyte for a lithium secondary battery, but also a non-aqueous electrolyte for a primary battery, a non-aqueous electrolyte for an electrochemical capacitor, and an electric double layer capacitor. It can also be used as an electrolytic solution for aluminum electrolytic capacitors.

<Lithium secondary battery>
The lithium secondary battery of the present invention basically comprises a negative electrode, a positive electrode, and the non-aqueous electrolyte of the present invention, and a separator is usually provided between the negative electrode and the positive electrode. .

(Negative electrode)
As the negative electrode active material constituting the negative electrode, metallic lithium, lithium-containing alloy, metal or alloy that can be alloyed with lithium, oxide capable of doping / dedoping lithium ion, doping / dedoping of lithium ion Any of the possible transition metal nitrides, carbon materials that can be doped / undoped with lithium ions, or mixtures thereof can be used. Examples of metals or alloys that can be alloyed with lithium (or lithium ions) include silicon, silicon alloys, tin, and tin alloys.
Among these, carbon materials that can be doped / undoped with lithium ions are preferable. Examples of such a carbon material include carbon black, activated carbon, artificial graphite, natural graphite, and amorphous carbon. The form of the carbon material may be any of a fibrous form, a spherical form, a potato form, and a flake form.

Specific examples of the amorphous carbon material include hard carbon, coke, mesocarbon microbeads (MCMB) fired at 1500 ° C. or less, and mesopause bitch carbon fiber (MCF).
Examples of the graphite material include natural graphite and artificial graphite. As artificial graphite, graphitized MCMB, graphitized MCF, and the like are used. Further, as the graphite material, a material containing boron can be used. In addition, as the graphite material, those coated with a metal such as gold, platinum, silver, copper, and tin, those coated with amorphous carbon, and those obtained by mixing amorphous carbon and graphite can be used. .

These carbon materials may be used alone or in combination of two or more. The carbon material is particularly preferably a carbon material having a (002) plane spacing d (002) of 0.340 nm or less as measured by X-ray analysis. Further, as the carbon material, graphite having a true density of 1.70 g / cm ³ or more or a highly crystalline carbon material having properties close thereto is also preferable.
When the carbon material as described above is used, the energy density of the battery can be further increased.

(Positive electrode)
Examples of the positive electrode active material constituting the positive electrode include transition metal oxides or transition metal sulfides such as MoS ₂ , TiS ₂ , MnO ₂ , and V ₂ O ₅ , LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiNi _X Co _(1-X) O ₂ [0 <X <1], composite oxide composed of lithium and transition metal such as LiFePO ₄ , polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, dimercaptothiadiazole, polyaniline complex Examples thereof include conductive polymer materials. Among these, a composite oxide composed of lithium and a transition metal is particularly preferable. When the negative electrode is lithium metal or a lithium alloy, a carbon material can also be used as the positive electrode. In addition, a mixture of a composite oxide of lithium and a transition metal and a carbon material can be used as the positive electrode.
Said positive electrode active material may be used by 1 type, and may mix and use 2 or more types. Since the positive electrode active material usually has insufficient conductivity, it is used together with a conductive auxiliary agent to constitute the positive electrode. Examples of the conductive assistant include carbon materials such as carbon black, amorphous whiskers, and graphite.

(Separator)
The separator is a film that electrically insulates the positive electrode and the negative electrode and transmits lithium ions, and examples thereof include a porous film and a polymer electrolyte.
A microporous polymer film is preferably used as the porous film, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, and polyester.
In particular, porous polyolefin is preferable, and specific examples include a porous polyethylene film, a porous polypropylene film, or a multilayer film of a porous polyethylene film and a polypropylene film. On the porous polyolefin film, other resin excellent in thermal stability may be coated.
Examples of the polymer electrolyte include a polymer in which a lithium salt is dissolved, a polymer swollen with an electrolytic solution, and the like.
The nonaqueous electrolytic solution of the present invention may be used for the purpose of obtaining a polymer electrolyte by swelling a polymer.

(Battery configuration)
The lithium secondary battery of this invention contains the said negative electrode active material, a positive electrode active material, and a separator. The lithium secondary battery of the present invention can take various known shapes, and can be formed into a cylindrical shape, a coin shape, a square shape, a film shape, or any other shape. However, the basic structure of the battery is the same regardless of the shape, and the design can be changed according to the purpose.
An example of the non-aqueous electrolyte secondary battery of the present invention is a coin-type battery shown in FIG.
In the coin-type battery shown in FIG. 1, a disc-shaped negative electrode 2, a separator 5 into which a non-aqueous electrolyte solution obtained by dissolving an electrolyte in a non-aqueous solvent, a disc-shaped positive electrode 1, stainless steel, or aluminum as necessary Spacer plates 7 and 8 are stacked in this order and accommodated between positive electrode can 3 (hereinafter also referred to as “battery can”) and sealing plate 4 (hereinafter also referred to as “battery can lid”). The The positive electrode can 3 and the sealing plate 4 are caulked and sealed via a gasket 6.

The lithium secondary battery of the present invention is obtained by charging / discharging a lithium secondary battery (lithium secondary battery before charge / discharge) including a negative electrode, a positive electrode, and the non-aqueous electrolyte of the present invention. A lithium secondary battery may also be used.
That is, the lithium secondary battery of the present invention is prepared by first preparing a lithium secondary battery before charge / discharge including a negative electrode, a positive electrode, and the non-aqueous electrolyte of the present invention, and then before the charge / discharge. It may be a lithium secondary battery (charged / discharged lithium secondary battery) produced by charging / discharging the lithium secondary battery one or more times.

  The use of the non-aqueous electrolyte of the embodiment of the present invention and the lithium secondary battery using the non-aqueous electrolyte is not particularly limited, and can be used for various known uses. For example, notebook computers, mobile computers, mobile phones, headphone stereos, video movies, LCD TVs, handy cleaners, electronic notebooks, calculators, radios, backup power applications, motors, automobiles, electric cars, motorcycles, electric bikes, bicycles, electric bicycles It can be widely used regardless of whether it is a small portable device or a large device, such as a lighting fixture, a game machine, a watch, a power tool, a camera.

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.
Hereinafter, synthesis examples of the novel unsaturated sultone compound of the present invention will be shown.
In addition, 5H-1,2-oxathiol-2,2-dioxide shown below is synonymous with 1,3-prop-1-ene sultone.

[Synthesis Example 1: Synthesis of 3-trimethylsilyl-5H-1,2-oxathiol-2,2-dioxide (Exemplary Compound 1)]
5H-1,2-oxathiol-2,2-dioxide (1.00 g, 8.32 mmol) was dissolved in tetrahydrofuran (30 ml) and cooled to −78 ° C., and lithium bistrimethylsilylamide (1.14 mol / L THF) was cooled. Solution, 7.7 ml, 8.7 mmol) was added and stirred for 2 hours. Subsequently, trimethylsilyl chloride (1.2 ml, 9.2 mmol) was added at the same temperature, and the mixture was stirred at −78 ° C. for 2 hours. A saturated aqueous ammonium chloride solution and water were added to the reaction solution, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated. The residue was purified by silica gel chromatography (eluent: hexane / ethyl acetate = 1/2) to give Exemplary Compound 1 (570.6 mg, yield 35.7%).
The NMR measurement result of Example Compound 1 was as follows.
¹ H-NMR (270 MHz, CDCl ₃ ) δ (ppm): 6.87 (1H, t, J = 2.0 Hz), 5.01 (2H, d, J = 2.0 Hz), 0.37 (9H , S)

[Synthesis Example 2: Synthesis of 3-triisopropylsilyl-5H-1,2-oxathiol-2,2-dioxide (Exemplary Compound 6)]
Exemplified compound 6 (1.07 g, yield 46.5%) was synthesized by the same synthesis method as in Synthesis Example 1 except that triisopropylsilyl trifluoromethanesulfonate was used instead of trimethylsilyl chloride.
The NMR measurement result of Example Compound 6 was as follows.
¹ H-NMR (270 MHz, CDCl ₃ ) δ (ppm): 6.93 (1H, t, J = 2.0), 5.06 (2H, d, J = 2.0), 1.36 (9H , M), 1.16 (24H, d, 7.2)

[Synthesis Example 3: Synthesis of 3- (dimethyl-t-butylsilyl) -5H-1,2-oxathiol-2,2-dioxide (Exemplary Compound 11)]
Exemplified compound 11 (430 mg, yield 22.1%) was synthesized by the same synthesis method as in Synthesis Example 1 except that dimethyl tert-butylsilyl trifluoromethanesulfonate was used instead of trimethylsilyl chloride.
The NMR measurement results of Example Compound 11 were as follows.
¹ H-NMR (270 MHz, CDCl ₃ ) δ (ppm): 6.91 (1H, t, J = 2.0), 5.03 (2H, d, J = 2.0), 1.00 (9H , S), 0.33 (6H, s)

[Example 1]
A lithium secondary battery was produced by the following procedure.
<Production of negative electrode>
20 parts by mass of artificial graphite, 80 parts by mass of natural graphite, 1 part by mass of carboxymethyl cellulose and 2 parts by mass of SBR latex were kneaded with an aqueous solvent to prepare a paste-like negative electrode mixture slurry.
Next, the negative electrode mixture slurry is applied to a negative electrode current collector made of a strip-shaped copper foil having a thickness of 18 μm, dried, and then compressed by a roll press to form a sheet formed of a negative electrode current collector and a negative electrode active material layer The negative electrode was obtained. The coating density of the negative electrode active material layer at this time was 10 mg / cm ² , and the packing density was 1.5 g / ml.

<Preparation of positive electrode>
A paste-like positive electrode mixture slurry was prepared by kneading 90 parts by mass of LiMn ₂ O ₄ , 5 parts by mass of acetylene black and 5 parts by mass of polyvinylidene fluoride using N-methylpyrrolidinone as a solvent.
Next, this positive electrode mixture slurry is applied to a positive electrode current collector made of a strip-shaped aluminum foil having a thickness of 20 μm, dried, and then compressed by a roll press to form a sheet-shaped positive electrode comprising a positive electrode current collector and a positive electrode active material Got. The coating density of the positive electrode active material layer at this time was 30 mg / cm ² , and the packing density was 2.5 g / ml.

<Preparation of non-aqueous electrolyte>
LiPF ₆ as an electrolyte was dissolved in ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC) mixed in a ratio of 34:33:33 (mass ratio) as a non-aqueous solvent. The electrolyte concentration was adjusted to 1 mol / liter.
To the solution obtained above, as an additive, the unsaturated sultone compound [Exemplary Compound 1] having vinyl atom as a substituent obtained in Synthesis Example 1 and vinylene carbonate, the total mass of the non-aqueous electrolyte The nonaqueous electrolyte solution was obtained by adding so that the content thereof was 0.5% by mass.

<Production of coin-type battery>
The above-mentioned negative electrode was 14 mm in diameter and the above-mentioned positive electrode was 13 mm in diameter, and each was punched into a disk shape to obtain a coin-shaped electrode. Further, a microporous polyethylene film having a thickness of 20 μm was punched into a disk shape having a diameter of 17 mm to obtain a separator.
The obtained negative electrode, separator, and positive electrode were laminated in this order in a battery can made of stainless steel (2032 size), and 20 μl of a non-aqueous electrolyte was injected to impregnate the separator, the positive electrode, and the negative electrode.
Further, an aluminum plate (thickness 1.2 mm, diameter 16 mm) and a spring are placed on the positive electrode, and the battery is sealed by caulking the battery can lid through a polypropylene gasket, and the diameter is 20 mm, height. A coin-type lithium secondary battery (hereinafter referred to as a test battery) having the configuration shown in FIG.
The initial characteristics of the obtained coin-type battery (test battery) were evaluated.

[Evaluation method]
<Evaluation of initial battery characteristics>
The test battery was charged at a constant current of 1 mA and a constant voltage of 4.2 V, and discharged to 2.85 V at a constant current of 1 mA for 10 cycles. At that time, the first charge / discharge efficiency was calculated from the charge capacity [mAh] at the first cycle and the discharge capacity [mAh] by the following formula.

Initial charge / discharge efficiency [%]
= Discharge capacity [mAh] at the first cycle / Charge capacity [mAh] at the first cycle × 100 [%]

  Furthermore, the battery was charged with a constant voltage of 4.0 V, and the battery was cooled to −10 ° C. in a thermostat using a Solartron, impedance measurement was performed, and a resistance value [Ω] at 0.2 Hz was set as an initial battery resistance. The results are shown in Table 1 below.

[Example 2]
Instead of the unsaturated sultone compound [Exemplary Compound 1] used for the preparation of the nonaqueous electrolytic solution, [Exemplary Compound 6] was added so that the content with respect to the total mass of the nonaqueous electrolytic solution was 0.5% by mass. Otherwise, a coin-type lithium secondary battery was obtained in the same manner as in Example 1.
The obtained coin-type battery was evaluated for initial characteristics in the same manner as in Example 1.

[Example 3]
Instead of the unsaturated sultone compound [Exemplary Compound 1] used for the preparation of the nonaqueous electrolytic solution, [Exemplary Compound 11] was added so that the content with respect to the total mass of the nonaqueous electrolytic solution was 0.5% by mass. Except for this, a coin-type battery was obtained in the same manner as in Example 1.
The obtained coin-type battery was evaluated for initial characteristics in the same manner as in Example 1.

[Example 4]
Instead of vinylene carbonate used for the preparation of the non-aqueous electrolyte, fluoroethylene carbonate was added so that the content with respect to the total mass of the non-aqueous electrolyte was 2.0% by mass, and the unsaturated sultone compound [Exemplary Compound 1] was changed to an amount such that the content with respect to the total mass of the non-aqueous electrolyte was 1.5% by mass, and a coin-type battery was obtained in the same manner as in Example 1.
The obtained coin-type battery was evaluated for initial characteristics in the same manner as in Example 1.

[Comparative Example 1]
The unsaturated sultone compound [Exemplary Compound 1] used for the preparation of the nonaqueous electrolytic solution is not added, and only vinylene carbonate (VC) as an additive is 0.5% by mass based on the total mass of the nonaqueous electrolytic solution. A coin-type battery was obtained in the same manner as in Example 1 except that the addition was made as described above.
The obtained coin-type battery was evaluated for initial characteristics in the same manner as in Example 1.

[Comparative Example 2]
In place of the unsaturated sultone compound [Exemplary Compound 1] used for the preparation of the non-aqueous electrolyte, 1,3-prop-1-ene sultone (comparative compound PRS) was used as the unsaturated sultone compound with respect to the total amount of the non-aqueous electrolyte. A coin-type battery was obtained in the same manner as in Example 1 except that the content was 0.5% by mass. The comparative compound PRS is an unsaturated sultone compound which does not have a substituent containing a silicon atom and is outside the scope of the present invention.

[Comparative Example 3]
The unsaturated sultone compound [Exemplary Compound 1] used for the preparation of the non-aqueous electrolyte is not added, and only fluoroethylene carbonate is used as an additive, so that the content with respect to the total mass of the non-aqueous electrolyte is 2.0% by mass. A coin-type battery was obtained in the same manner as Example 4 except for the addition.
The obtained coin-type battery was evaluated for initial characteristics in the same manner as in Example 1.

[Comparative Example 4]
In place of the unsaturated sultone compound [Exemplary Compound 1] used for the preparation of the non-aqueous electrolyte, 1,3-prop-1-ene sultone (comparative compound PRS) was used as the unsaturated sultone compound with respect to the total amount of the non-aqueous electrolyte. A coin-type battery was obtained in the same manner as in Example 4 except that the content was 1.5% by mass. The comparative compound PRS is an unsaturated sultone compound which does not have a substituent containing a silicon atom and is outside the scope of the present invention.
The obtained coin-type battery was evaluated for initial characteristics in the same manner as in Example 1.

The evaluation results of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1.
Furthermore, the evaluation results of Example 4 and Comparative Examples 3 and 4 are shown in Table 2.

From the results of Table 1, it can be seen that the lithium secondary batteries of Examples 1 to 3 and Comparative Examples 1 and 2 have no problem in initial efficiency and initial discharge capacity. Compared to Comparative Example 1 containing no unsaturated sultone compound, in Examples 1 to 3, it was confirmed that the initial resistance was kept low and the output characteristics were improved. On the other hand, an increase in initial resistance was confirmed in Comparative Example 2 in which PRS, which is a comparative unsaturated sultone compound, was added.
From the results of Table 2, it can be seen that the lithium secondary batteries of Example 4 and Comparative Examples 3 and 4 have no problem in initial efficiency and initial discharge capacity. As compared with Comparative Example 3 containing no unsaturated sultone compound, it was confirmed that Example 4 had low initial resistance and improved output characteristics. On the other hand, an increase in initial resistance was confirmed in Comparative Example 4 in which PRS, which is a comparative unsaturated sultone compound, was added.

The disclosure of Japanese application 2009-218062 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims (12)

Containing an unsaturated sultone compound having a substituent containing a silicon atom,
A non-aqueous electrolyte for a lithium secondary battery, wherein the unsaturated sultone compound having a substituent containing a silicon atom is a compound represented by the following general formula (1).

[In General Formula (1), R ¹ represents —SiR ⁵ R ⁶ R ⁷ , and R ² , R ^3, and R ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, carbon An alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms is represented. R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or Represents a phenyl group. m represents 1. ] In the general formula (1), R ² , R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or 2 to 6 carbon atoms. R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, or 2 carbon atoms. The nonaqueous electrolytic solution for a lithium secondary battery according to claim 1, which is ˜4 alkynyl group, C 1-4 alkoxy group, or phenyl group. In the general formula (1), R ² , R ³ and R ⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, an ethyl group, a vinyl group, a propenyl group, a propargyl group, or trifluoromethyl. The nonaqueous electrolytic solution for a lithium secondary battery according to claim 2, which is a base. The unsaturated sultone compound having a substituent containing a silicon atom is 3-trimethylsilyl-5H-1,2-oxathiol-2,2-dioxide, 3- (dimethyl-t-butylsilyl) -5H-1,2- 2. The lithium secondary according to claim 1, which is at least one selected from the group consisting of oxathiol-2,2-dioxide and 3-triisopropylsilyl-5H-1,2-oxathiol-2,2-dioxide. Non-aqueous electrolyte for batteries . Furthermore, the nonaqueous electrolyte for lithium secondary batteries of Claim 1 containing the compound represented by following General formula (2).

[In General Formula (2), R ⁸ and R ⁹ each independently represent a hydrogen atom, a methyl group, an ethyl group, or a propyl group. ] Furthermore, the nonaqueous electrolyte for lithium secondary batteries of Claim 1 containing the compound represented by following General formula (3).

[In General Formula (3), X ¹ , X ² , X ³ and X ⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, or an alkyl having 1 to 3 carbon atoms which may be substituted with a fluorine atom. Indicates a group. However, X ^{1 to} X ⁴ are not simultaneously hydrogen atoms. ] The content of the compound represented by the general formula (1) is lithium secondary according to claim 1 which is 0.001 wt% to 10 wt% with respect to the nonaqueous electrolyte solution total mass for a lithium secondary battery Non-aqueous electrolyte for batteries . The content of the compound represented by the general formula (2) is, lithium secondary according to claim 5 which is 0.001 wt% to 10 wt% with respect to the nonaqueous electrolyte solution total mass for a lithium secondary battery Non-aqueous electrolyte for batteries . The content of the compound represented by the general formula (3) is, lithium secondary according to claim 6 which is 0.001 wt% to 10 wt% with respect to the nonaqueous electrolyte solution total mass for a lithium secondary battery Non-aqueous electrolyte for batteries . An additive for a lithium secondary battery represented by the following general formula (1).

[In General Formula (1), R ¹ represents —SiR ⁵ R ⁶ R ⁷ , and R ² , R ^3, and R ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, carbon An alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms is represented. R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or Represents a phenyl group. m represents 1. ] At least selected from positive electrode and metal lithium, lithium-containing alloy, metal or alloy capable of alloying with lithium, oxide capable of doping / de-doping lithium ion, lithium ion doping material, or a mixture thereof The lithium secondary battery containing the negative electrode which contains 1 type as a negative electrode active material, and the non-aqueous electrolyte for lithium secondary batteries of Claim 1. At least selected from positive electrode and metal lithium, lithium-containing alloy, metal or alloy capable of alloying with lithium, oxide capable of doping / de-doping lithium ion, lithium ion doping material, or a mixture thereof The lithium secondary battery obtained by charging / discharging the lithium secondary battery containing the negative electrode which contains 1 type as a negative electrode active material, and the non-aqueous electrolyte for lithium secondary batteries of Claim 1.