JPWO2013168716A1 - Non-aqueous electrolyte, power storage device using the same, and dihalophosphate compound - Google Patents

Abstract

The present invention is a non-aqueous electrolyte that can improve electrochemical characteristics at high temperatures, and in a non-aqueous electrolyte in which an electrolyte salt is dissolved in a non-aqueous solvent, the following general formula (I And a specific dihalophosphate compound used for the non-aqueous electrolyte, an electricity storage device using the nonaqueous electrolyte, and a power storage device using the same. Wherein R 1 and R 2 are an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 2 to 6 carbon atoms. An alkenyloxy group, an alkynyloxy group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms, X1 and X2 each represents a fluorine atom or a chlorine atom, m represents 1 or 2. When m is 1, R3 is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, or 6 to 6 carbon atoms. 12 represents an aryl group, and when m is 2, it represents an alkylene group having 2 to 6 carbon atoms, an alkenylene group having 4 to 8 carbon atoms, or an alkynylene group having 4 to 8 carbon atoms.)

Description

  The present invention relates to a nonaqueous electrolytic solution capable of improving electrochemical properties at high temperatures, an electricity storage device using the same, and a specific dihalophosphate compound used in them.

  In recent years, power storage devices, in particular lithium secondary batteries, have been widely used as power sources for electronic devices such as mobile phones and laptop computers, and for electric vehicles and power storage. Batteries mounted on these electronic devices and automobiles are likely to be used under the high temperature of midsummer or in an environment warmed by heat generated by the electronic devices.

A lithium secondary battery, which is a kind of power storage device, is mainly composed of a positive electrode and a negative electrode containing a material capable of occluding and releasing lithium, a non-aqueous electrolyte solution composed of a lithium salt and a non-aqueous solvent. Carbonates such as carbonate (EC) and propylene carbonate (PC) are used.
As negative electrodes of lithium secondary batteries, lithium metal, metal compounds capable of inserting and extracting lithium (metal simple substance, oxide, alloy with lithium, etc.) and carbon materials are known. In particular, non-aqueous electrolyte secondary batteries using carbon materials that can occlude and release lithium, such as coke and graphite (artificial graphite, natural graphite), are widely used.
Since the above negative electrode material stores and releases lithium and electrons at a very low potential equivalent to that of lithium metal, many solvents may undergo reductive decomposition, particularly at high temperatures. Regardless of the type, some of the solvent in the electrolyte solution undergoes reductive decomposition on the negative electrode, and the lithium ion migration is hindered by deposition of decomposition products and gas generation. There was a problem of deteriorating characteristics. Furthermore, lithium secondary batteries using lithium metal, alloys thereof, simple metals such as tin or silicon, and oxides as negative electrode materials have high initial capacities, but fine powders progress during the cycle. In comparison, it is known that reductive decomposition of a non-aqueous solvent occurs at an accelerated rate, and battery performance such as battery capacity and cycle characteristics deteriorates particularly at high temperatures.

On the other hand, materials capable of occluding and releasing lithium, such as LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFePO _{4 and the} like used as the positive electrode material, store lithium and electrons at a noble voltage of 3.5 V or more on the basis of lithium. Because of the release, many solvents have the potential to undergo oxidative decomposition, especially at high temperatures, and some of the solvent in the electrolyte solution is oxidatively decomposed on the positive electrode regardless of the type of positive electrode material. However, the deposition of decomposition products and the generation of gas hinder the movement of lithium ions, resulting in deterioration of battery characteristics such as cycle characteristics.

In spite of the above situation, electronic devices equipped with lithium secondary batteries are becoming more and more multifunctional and power consumption is increasing. As a result, the capacity of lithium secondary batteries has been increasing, and the volume occupied by non-aqueous electrolyte in the battery has become smaller, such as increasing the electrode density and reducing the useless space volume in the battery. . Therefore, the battery performance at high temperature is likely to be degraded by a slight decomposition of the non-aqueous electrolyte.
Patent Document 1 proposes a nonaqueous electrolytic solution containing a phosphoric ester compound such as triethylphosphonoacetate, and it is shown that charging characteristics and storage characteristics can be improved.

International Publication No. 2008/123038

  An object of this invention is to provide the nonaqueous electrolyte which can improve the electrochemical characteristic under high temperature, the electrical storage device using the same, and a specific dihalophosphate compound.

The present inventors examined in detail the performance of the non-aqueous electrolyte described in Patent Document 1. As a result, the non-aqueous electrolyte disclosed in Patent Document 1 cannot be said to be sufficiently satisfactory with respect to the problem of improving the cycle characteristics at high temperatures, particularly at high charging voltages. It was.
Therefore, the present inventors have made extensive studies to solve the above problems, and in a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a non-aqueous solvent, a specific dihalophosphate compound is added to the non-aqueous electrolyte solution. It has been found that the inclusion can improve the electrochemical characteristics of the electricity storage device at high temperature, particularly the cycle characteristics of the lithium battery, and the present invention has been completed.

That is, the present invention provides the following (1) to (4).
(1) A non-aqueous electrolyte in which an electrolyte salt is dissolved in a non-aqueous solvent, wherein the non-aqueous electrolyte contains a dihalophosphate compound represented by the following general formula (I): Electrolytic solution.

Wherein R ¹ and R ² 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 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, An alkenyloxy group having 2 to 6 carbon atoms, an alkynyloxy group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms, wherein X ¹ and X ² are each independently Represents a fluorine atom or a chlorine atom, and m represents 1 or 2.
R ³ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms when m is 1. When m is 2, an alkylene group having 2 to 6 carbon atoms, an alkenylene group having 4 to 8 carbon atoms, or an alkynylene group having 4 to 8 carbon atoms is shown.
At least one hydrogen atom of the group represented by R ¹ or R ² may be substituted with a halogen atom. When R ¹ and R ² are alkyl groups or alkoxy groups, R ¹ and R ² may be bonded to form a ring structure. )

(2) The non-aqueous electrolyte further contains at least one selected from the compound represented by the following general formula (II) and the compound represented by the general formula (III) .

(In the formula, R ⁴ and R ⁵ have the same meanings as R ¹ and R ² , and R ⁶ is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and an alkynyl group having 3 to 6 carbon atoms. Or an aryl group having 6 to 12 carbon atoms, R ⁷ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and X ³ represents a fluorine atom or a chlorine atom.
At least one hydrogen atom of the groups R ⁴ and R ⁵ may be substituted with a halogen atom. When R ⁴ and R ⁵ are an alkyl group or an alkoxy group, R ⁴ and R ⁵ may be bonded to form a ring structure. )

（式中、Ｒ⁸及びＲ⁹はＲ¹及びＲ²と同義であり、Ｒ¹⁰はＲ⁶と同義であり、Ｒ¹¹及びＲ¹²は同一でも異なっていてもよく、水素原子、又は少なくとも一つの水素原子がハロゲン原子で置換されていてもよい炭素数１〜６のアルキル基を示し、ｎは１〜４の整数を示す。また、Ｒ⁸及びＲ⁹がアルキル基又はアルコキシ基の場合は、Ｒ⁸及びＲ⁹は結合して環構造を形成してもよい。）

(Wherein R ⁸ and R ⁹ have the same meanings as R ¹ and R ² , R ¹⁰ has the same meaning as R ⁶ , R ¹¹ and R ¹² may be the same or different, and are a hydrogen atom or at least one 1 represents an alkyl group having 1 to 6 carbon atoms in which one hydrogen atom may be substituted with a halogen atom, and n represents an integer of 1 to 4. When R ⁸ and R ⁹ are an alkyl group or an alkoxy group, , R ⁸ and R ⁹ may combine to form a ring structure.)

(3) A power storage device comprising a positive electrode, a negative electrode, and the non-aqueous electrolyte according to (1) or (2).

(4) A dihalophosphate compound represented by the following general formula (IV).

Wherein R ¹³ and R ¹⁴ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryloxy having 6 to 12 carbon atoms. Represents a group, X ⁴ represents a fluorine atom or a chlorine atom, and p represents 1 or 2.
R ¹⁵ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms when p is 1. When p is 2, an alkylene group having 2 to 6 carbon atoms, an alkenylene group having 4 to 8 carbon atoms, or an alkynylene group having 4 to 8 carbon atoms is shown.
At least one hydrogen atom of the group represented by R ¹³ or R ¹⁴ may be substituted with a halogen atom. When R ¹³ and R ¹⁴ are an alkyl group or an alkoxy group, R ¹³ and R ¹⁴ may be bonded to form a ring structure. However, R ¹³ and R ¹⁴ are both an alkoxy group having 1 to 6 carbon atoms, and R ¹⁵ is an alkyl group having 1 to 2 carbon atoms. )

  According to the present invention, there are provided a nonaqueous electrolytic solution capable of improving electrochemical characteristics under high temperature, particularly high temperature cycle characteristics, a power storage device such as a lithium battery using the same, and a specific dihalophosphate compound used in them. can do.

  The present invention relates to a nonaqueous electrolytic solution capable of improving electrochemical properties at high temperatures, an electricity storage device using the nonaqueous electrolytic solution, and a specific dihalophosphate compound.

[Non-aqueous electrolyte]
The non-aqueous electrolyte of the present invention contains at least one dihalophosphate compound represented by the above general formula (I) in the non-aqueous electrolyte in which an electrolyte salt is dissolved in a non-aqueous solvent. This is a non-aqueous electrolyte solution.

The reason why the nonaqueous electrolytic solution of the present invention can greatly improve the cycle characteristics at high temperatures is not necessarily clear, but is considered as follows.
The dihalophosphate compound of the present invention has a P (═O) C— group, a> C═O group and two halogen atoms as represented by the general formula (I).
By having two halogen atoms, compared to the case of having only one halogen atom or the case of not having a halogen atom, it is easy to be decomposed at the initial stage of charge and discharge, and it is dense on the positive and negative electrodes. It is considered that a film having high heat resistance can be formed. In addition, since the film has two different relatively weak electron-withdrawing substituents, a P (═O) C— group and a> C═O group that function as sites for slowly trapping lithium ions, lithium ion conduction It is considered that the property was remarkably improved, and a remarkable improvement effect of the high-temperature cycle characteristics was obtained.
Furthermore, when a compound in which one halogen atom is substituted or a compound in which a halogen atom is not substituted is used in combination, the high-temperature cycle characteristics are further improved. The reason is that a compound in which one halogen atom is substituted or a compound in which a halogen atom is not substituted is less decomposable than a dihalophosphate compound represented by the general formula (I) in which two halogen atoms are substituted. From this, it is considered that the effect of adding the dihalophosphate compound represented by the general formula (I) is sustained for a long time.

  The dihalophosphate compound contained in the nonaqueous electrolytic solution of the present invention is represented by the following general formula (I).

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｘ¹、Ｘ²、及びｍは前記のとおりである。）

(In the formula, R ¹ , R ² , R ³ , X ¹ , X ² , and m are as described above.)

R ¹ and R ^{2 in} formula (I) are each independently an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and at least one hydrogen atom is a halogen atom. An optionally substituted alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and at least one hydrogen atom being a halogen atom An optionally substituted alkoxy group having 1 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and at least one hydrogen atom substituted with a halogen atom An optionally substituted alkynyloxy group having 3 to 6 carbon atoms and at least one hydrogen atom having 6 to 12 carbon atoms optionally substituted with a halogen atom An aryl group or an aryloxy group having 6 to 12 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom.

Specific examples of R ¹ and R ² include methyl groups, ethyl groups, n-propyl groups, n-butyl groups, n-pentyl groups, n-hexyl groups and other linear alkyl groups, isopropyl groups, sec- Branched alkyl groups such as butyl group, tert-butyl group, tert-amyl group, cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 2-propenyl group, 2-butenyl group, 3 -Butenyl group, 4-pentenyl group, 5-hexenyl group, 2-methyl-2-propenyl group, alkenyl group such as 3-methyl-2-butenyl group, 2-propynyl group, 3-butynyl group, 4-pentynyl group , 5-hexynyl group, 1-methyl-2-propynyl group, 1,1-dimethyl-2-propynyl group and other alkynyl groups, methoxy group, ethoxy group, n-propoxy group Branches such as linear alkoxy groups such as xoxy group, n-butoxy group, n-pentyloxy group, n-hexyloxy group, iso-propoxy group, sec-butoxy group, tert-butoxy group, tert-amyloxy group Chain alkoxy group, cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group and other cycloalkoxy groups, 2-propenyloxy group, 2-butenyloxy group, 3-butenyloxy group, 4-pentenyloxy group, Alkenyloxy groups such as 5-hexenyloxy group, 2-propynyloxy group, 3-butynyloxy group, 4-pentynyloxy group, 5-hexynyloxy group, 1-methyl-2-propynyloxy group, 1,1-dimethyl- 2-propynyloxy group, 3-methyl-2-butynyloxy group, etc. Alkyl groups in which a part of hydrogen atoms such as alkynyloxy group, fluoromethyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group are substituted with fluorine atoms, fluoromethoxy group, trifluoromethoxy group, 2, Alkoxy groups in which some hydrogen atoms such as 2,2-trifluoroethoxy groups are substituted with fluorine atoms, phenyl groups, 2-methylphenyl groups, 3-methylphenyl groups, 4-methylphenyl groups, 4-tert- Butylphenyl group, 2,4,6-trimethylphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluorophenyl group, 3, 4-difluorophenyl group, 2,4,6-trifluorophenyl group, pentafluorophenyl group, 4-trifluoromethyl Aryl group such as phenyl group, phenyloxy group, 2-methylphenyloxy group, 3-methylphenyloxy group, 4-methylphenyloxy group, 4-tert-butylphenyloxy group, 2,4,6-trimethylphenyloxy Group, 2-fluorophenyloxy group, 3-fluorophenyloxy group, 4-fluorophenyloxy group, 2,4-difluorophenyloxy group, 2,6-difluorophenyloxy group, 3,4-difluorophenyloxy group, Aryloxy groups such as 2,4,6-trifluorophenyloxy group, pentafluorophenyloxy group, 4-trifluoromethylphenyloxy group, butane-1,4-diyl group, pentane-1,5-diyl group, _{- (CH 2) 3 O -} , - (CH 2) 4 O-, ethane-1,2-dioxy group, prop 1,2-dioxy group, 1,3-dioxy group, and substituted groups form a ring R ¹ and R ^2, such as butane-2,3-dioxy group suitably.
Among the above, R ¹ and R ² are more preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkynyloxy group having 3 to 6 carbon atoms, and an alkoxy having 1 to 2 carbon atoms. Groups are more preferred. More specifically, R ¹ and R ² are methyl group, ethyl group, n-propyl group, n-butyl group, methoxy group, ethoxy group, n-propoxy group, n-butoxy group, phenyl group, phenyloxy Group, ethane-1,2-dioxy group is preferable, and methoxy group and ethoxy group are more preferable.

R ^{3 in the} general formula (I), when m is 1, is an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and at least one hydrogen atom is halogen. An optionally substituted alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, or at least one hydrogen atom being a halogen atom An aryl group having 6 to 12 carbon atoms which may be substituted with
Among these, R ³ is an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and 2 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom. -6 alkenyl group, C3-C6 alkynyl group in which at least one hydrogen atom may be substituted with a halogen atom, or C6-C12 aryl in which at least one hydrogen atom is substituted with a halogen atom Group is more preferable, and an alkenyl group having 2 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, or 3 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom. The alkynyl group is more preferable.
When R ³ is an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, it may be linear or branched, and the branched chains are bonded to each other. A ring may be formed. The number of carbon atoms is more preferably 1 to 3.
When R ³ is an alkenyl group having 2 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, the number of carbon atoms is more preferably 2 to 3.
When R ³ is an alkynyl group having 3 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, the number of carbon atoms is more preferably 3 to 4.
When R ³ is an aryl group having 6 to 12 carbon atoms in which at least one hydrogen atom is substituted with a halogen atom, the number of carbon atoms is more preferably 6 to 8.

R ^{3 in the} general formula (I), when m is 2, is an alkylene group having 2 to 6 carbon atoms or an alkenylene group having 4 to 8 carbon atoms in which at least one hydrogen atom may be substituted with halogen. Represents an alkynylene group having 4 to 8 carbon atoms, and among them, an alkenylene group having 4 to 8 carbon atoms or an alkynylene group having 4 to 8 carbon atoms is preferable.

Specific examples of R ³ include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl, isopropyl, sec-butyl, Branched alkyl groups such as tert-butyl group and tert-amyl group, cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group, vinyl group, 2-propenyl group, 2-butenyl group, 3 -Butenyl group, 4-pentenyl group, 5-hexenyl group, 2-methyl-2-propenyl group, alkenyl group such as 3-methyl-2-butenyl group, 2-propynyl group, 3-butynyl group, 4-pentynyl group , 5-hexynyl group, 1-methyl-2-propynyl group, 1,1-dimethyl-2-propynyl group and other alkynyl groups, fluoromethyl group, trifluoro Alkyl group, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group in which a part of hydrogen atoms such as til group and 2,2,2-trifluoroethyl group are substituted with fluorine atoms 4-tert-butylphenyl group, 2,4,6-trimethylphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluoro Aryl groups such as phenyl group, 3,4-difluorophenyl group, 2,4,6-trifluorophenyl group, pentafluorophenyl group, 2-trifluoromethylphenyl group, 4-trifluoromethylphenyl group, ethane-1 , 2-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, butane-2,3 Alkylene group such as diyl group, alkenylene group such as 2-butene-1,4-diyl group, 3-hexene-2,5-diyl group, 2-butyne-1,4-diyl group, 3-hexyne-2, Preferable examples include alkynylene groups such as 5-diyl group and 2,5-dimethyl-3-hexyne-2,5-diyl group.

Among these, when m is 1, R ³ is methyl group, ethyl group, n-propyl group, n-butyl group, isopropyl group, vinyl group, 2-propenyl group, 2-butenyl group, 3-butenyl. Group, 2-propynyl group, 3-butynyl group, 1-methyl-2-propynyl group, 1,1-dimethyl-2-propynyl group, pentafluorophenyl group, 2-trifluoromethylphenyl group, 4-trifluoromethyl A phenyl group is more preferable, and when m is 2, ethane-1,2-diyl group, propane-1,2-diyl group, 2-butene-1,4-diyl group, 2-butyne-1,4- A diyl group, a 3-hexyne-2,5-diyl group, and a 2,5-dimethyl-3-hexyne-2,5-diyl group are more preferable. When m is 1, a methyl group, ethyl group, isopropyl group, 2-propynyl group, pentafluorophenyl group, or 2-trifluoromethylphenyl group is more preferable. When m is 2, ethane-1, 2-diyl group, 2-butene-1,4-diyl group, and 2-butyne-1,4-diyl group are more preferable.

X ¹ and X ^{2 in} the general formula (I) may be the same or different and each represents a fluorine atom or a chlorine atom, and more preferably a fluorine atom.

Specific examples of the dihalophosphate compound represented by the general formula (I) include the following compounds.
(1) In the case of m = 1, the following compounds A1-A80 are mentioned suitably.

  Among the above-mentioned compounds, more preferable are A1, A3 to A8, A10, A14, A22 to A24, A28 to A32, A38, A39, A41 to A48, A50, A51, A56, A61 to A66, One kind or two or more kinds selected from compounds having a structure of A68 to A75, A78, and A79 can be mentioned.

(2) In the case of m = 2, the following compounds A81 to A97 are preferable.

  Among the above compounds, one or more selected from the compounds having the structures of A82, A86-2, and A87 to A96 are preferable.

  Among the dihalophosphate compounds represented by the general formula (I), more preferably, when m = 1, A6 to A8, A22, A23, A32, A38, A41 to A48, A56, One or two or more types selected from compounds having the structures of A62, A63, A65, A66, A69 to A74, and A78 to A80 may be mentioned. When m = 2, the above structures of A87 to A90 and A93 to A96 1 type or 2 types or more chosen from the compound which has is mentioned.

  Among the dihalophosphate compounds represented by the general formula (I), particularly preferred are those in which, when m = 1, ethyl 2- (diethylphosphoryl) -2,2-difluoroacetate (Structural Formula A6), 2-propynyl 2- (diethylphosphoryl) -2,2-difluoroacetate (Structural Formula A23), ethyl 2- (ethoxy (ethyl) phosphoryl) -2,2-difluoroacetate (Structural Formula A32), methyl 2- (dimethoxy) Phosphoryl) -2,2-difluoroacetate (Structural Formula A41), methyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A44), ethyl 2- (diethoxyphosphoryl) -2,2-difluoro Acetate (Structural Formula A46), ethyl 2-chloro-2- (diethoxyphosphoryl) -2-phenyl Oroacetate (Structural Formula A47), ethyl 2,2-dichloro-2- (diethoxyphosphoryl) acetate (Structural Formula A48), ethyl 2- (diphenoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A56), Propyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A62), Hexyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A65), Isopropyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A66), cyclohexyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A69), vinyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate ( Structural formula A70), allyl 2- (diethoxyphosphori) ) -2,2-difluoroacetate (Structural Formula A71), 2-propynyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A72), 2-propynyl 2,2-dichloro-2- (di-) Ethoxyphosphoryl) acetate (Structural Formula A73), 1-methyl-2-propynyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural Formula A74), pentafluorophenyl 2- (diethoxyphosphoryl) -2, 1 type or 2 or more types chosen from 2-difluoroacetate (Structural formula A78) and 2-trifluoromethyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate (Structural formula A79) are mentioned, m = 2 Ethane-1,2-diyl bis (2- (diethoxyphosphoryl) -2,2-difluoroacetate Tate) (Structural Formula A88), 2-butene-1,4-diyl bis (2- (diethoxyphosphoryl) -2,2-difluoroacetate) (Structural Formula A93), 2-butyne-1,4-diyl bis One type or two or more types selected from (2- (diethoxyphosphoryl) -2,2-difluoroacetate) (Structural Formula A95) may be used.

  In the non-aqueous electrolyte of the present invention, the content of the dihalophosphate compound represented by the general formula (I) contained in the non-aqueous electrolyte is 0.001 to 10% by mass in the non-aqueous electrolyte. preferable. If the content is 10% by mass or less, a film is excessively formed on the electrode and the high-temperature cycle characteristics are less likely to be deteriorated. If the content is 0.001% by mass or more, the film is sufficiently formed, and the high temperature The effect of improving cycle characteristics is enhanced. The content is preferably 0.05% by mass or more, and more preferably 0.2% by mass or more in the nonaqueous electrolytic solution. Further, the upper limit is preferably 8% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

  The non-aqueous electrolyte of the present invention preferably further contains one or more selected from the compound represented by the following general formula (II) and the compound represented by the general formula (III).

（式中、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、及びＸ³は前記のとおりである。）

(In the formula, R ⁴ , R ⁵ , R ⁶ , R ⁷ , and X ³ are as described above.)

（式中、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹、Ｒ¹²、及びｎは前記のとおりである。）

(In the formula, R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , and n are as defined above.)

R ⁴ and R ⁵ in the general formula (II) have the same meanings as R ¹ and R ^{2 in} the general formula (I).
R ^{6 in the} general formula (II) is an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and at least one hydrogen atom may be substituted with a halogen atom. An alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, or carbon in which at least one hydrogen atom is substituted with a halogen atom An aryl group having 6 to 12 carbon atoms, among which an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and an alkynyl group having 3 to 6 carbon atoms are more preferable, and an alkyl group having 1 to 4 carbon atoms Further, an alkynyl group having 3 to 6 carbon atoms is more preferable.

Specific examples of R ⁶ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group and other linear alkyl groups, an isopropyl group, a sec-butyl group, Branched alkyl groups such as tert-butyl group and tert-amyl group, cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group, vinyl group, 2-propenyl group, 2-butenyl group, 3 -Butenyl group, 4-pentenyl group, 5-hexenyl group, 2-methyl-2-propenyl group, alkenyl group such as 3-methyl-2-butenyl group, 2-propynyl group, 3-butynyl group, 4-pentynyl group , 5-hexynyl group, 1-methyl-2-propynyl group, 1,1-dimethyl-2-propynyl group and other alkynyl groups, fluoromethyl group, trifluoro Alkyl group, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group in which a part of hydrogen atoms such as til group and 2,2,2-trifluoroethyl group are substituted with fluorine atoms 4-tert-butylphenyl group, 2,4,6-trimethylphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluoro Preferred examples include aryl groups such as phenyl group, 3,4-difluorophenyl group, 2,4,6-trifluorophenyl group, pentafluorophenyl group, 2-trifluoromethylphenyl group and 4-trifluoromethylphenyl group. It is done.
Among these, R ⁶ is methyl group, ethyl group, isopropyl group, vinyl group, 2-propenyl group, 2-butenyl group, 3-butenyl group, 2-methyl-2-propenyl group, 2-propynyl group, 3 -Butynyl group, pentafluorophenyl group, 2-trifluoromethylphenyl group, 4-trifluoromethylphenyl group, 1-methyl-2-propynyl group or 1,1-dimethyl-2-propynyl group is preferred, methyl group , Ethyl group, isopropyl group, 2-propynyl group, 2-trifluoromethylphenyl group, or 4-trifluoromethylphenyl group is more preferable.

R ^{7 in the} general formula (II) represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and in particular, an alkyl having 1 to 4 carbon atoms. Group is more preferable, and an alkyl group having 1 to 2 carbon atoms is still more preferable.
Specific examples of R ⁷ include hydrogen atoms, methyl groups, ethyl groups, n-propyl groups, n-butyl groups, n-pentyl groups, n-hexyl groups and other linear alkyl groups, isopropyl groups, sec- Preferable examples include branched alkyl groups such as butyl group, tert-butyl group, and tert-amyl group, and cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl group. Among these, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an n-butyl group is preferable, and a hydrogen atom, a methyl group, or an ethyl group is more preferable.

X ^{3 in the} general formula (II) represents a fluorine atom or a chlorine atom, and a fluorine atom is more preferable.

  Specific examples of the compound represented by the general formula (II) include the following compounds B1 to B77.

  Among the compounds represented by the general formula (II), more preferable are B1, B2, B4, B5, B8, B12 to B18, B21 to B23, B25 to B27, B33, B34, B36. 1 type, or 2 or more types chosen from the compound which has the structure of -B45, B50, B55-B57, B60, B62-B66, B70-B75 is mentioned.

  Among the compounds represented by the general formula (II), particularly preferred are ethyl 2- (diethylphosphoryl) -2-fluoroacetate (structural formula B5), 2-propynyl 2- (diethylphosphoryl) -2. -Fluoroacetate (Structural Formula B17), methyl 2- (dimethoxyphosphoryl) -2-fluoroacetate (Structural Formula B36), methyl 2- (dimethoxyphosphoryl) -2-fluoropropanoate (Structural Formula B37), methyl 2- (Diethoxyphosphoryl) -2-fluoroacetate (structural formula B39), ethyl 2- (dimethoxyphosphoryl) -2-fluoroacetate (structural formula B40), ethyl 2- (diethoxyphosphoryl) -2-fluoroacetate (structural formula B41), isopropyl 2- (diethoxyphosphoryl) -2-fluoro Acetate (structural formula B60), vinyl 2- (diethoxyphosphoryl) -2-fluoroacetate (structural formula B63), allyl 2- (diethoxyphosphoryl) -2-fluoroacetate (structural formula B64), 2-propynyl 2- One or two or more kinds selected from (diethoxyphosphoryl) -2-fluoroacetate (Structural Formula B65) and ethyl 2- (diethoxyphosphoryl) -2-fluoropropanoate (Structural Formula B73) may be mentioned.

R ⁸ and R ^{9 in} the general formula (III) have the same meanings as R ¹ and R ^{2 in} the general formula (I).
R ^{10 in the} general formula (III) has the same meaning as R ^{6 in the} general formula (I).
R ¹¹ and R ¹² in the general formula (III) have the same meaning as R ^{7 in the} general formula (II).
In the general formula (III), n represents an integer of 1 to 4, more preferably 1 to 2, and still more preferably 1.

  Specific examples of the compound represented by the general formula (III) include the following compounds C1 to C80.

  Among the compounds represented by the general formula (III), more preferable examples include C1 to C6, C12 to 19, C22 to C24, C32, C33, C37 to C43, C45, C46, C51, and C56 to One type or two or more types selected from compounds having a structure of C58, C61, C63 to C67, C71 to C73, and C78 may be mentioned.

  Among the compounds represented by the general formula (III), particularly preferred are ethyl 2- (diethylphosphoryl) acetate (structural formula C4), 2-propynyl 2- (diethylphosphoryl) acetate (structural formula C18). Methyl 2- (dimethoxyphosphoryl) acetate (Structural Formula C37), methyl 2- (diethoxyphosphoryl) acetate (Structural Formula C39), ethyl 2- (dimethoxyphosphoryl) acetate (Structural Formula C40), ethyl 2- (diethoxy) Phosphoryl) acetate (Structural Formula C41), ethyl 2- (diethoxyphosphoryl) propanoate (Structural Formula C42), propyl 2- (diethoxyphosphoryl) acetate (Structural Formula C57), isopropyl 2- (diethoxyphosphoryl) acetate (Structure) Formula C61), vinyl 2- (di Toxyl phosphoryl) acetate (Structural Formula C64), allyl 2- (diethoxyphosphoryl) acetate (Structural Formula C65), 2-propynyl 2- (diethoxyphosphoryl) acetate (Structural Formula C66) Can be mentioned.

  In the nonaqueous electrolytic solution of the present invention, the content of one or more compounds selected from the compound represented by the general formula (II) and the compound represented by the general formula (III) contained in the nonaqueous electrolytic solution Is preferably 0.001 to 10% by mass in the non-aqueous electrolyte. If the content is 10% by mass or less, a film is excessively formed on the electrode and the high-temperature cycle characteristics are less likely to be deteriorated. If the content is 0.001% by mass or more, the film is sufficiently formed, and the high temperature The effect of improving cycle characteristics is enhanced. The content is preferably 0.05% by mass or more, and more preferably 0.2% by mass or more in the nonaqueous electrolytic solution. Further, the upper limit is preferably 8% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

  In the non-aqueous electrolytic solution of the present invention, the dihalophosphate compound represented by the general formula (I) is combined with a non-aqueous solvent, an electrolyte salt, and other additives described below, so that electrochemical characteristics at high temperature are obtained. Expresses a unique effect of improving synergistically.

[Nonaqueous solvent]
Examples of the non-aqueous solvent used in the non-aqueous electrolyte of the present invention include one or more selected from cyclic carbonates, chain esters, ethers, amides, sulfones, and lactones, and at least one cyclic carbonate. It is preferable that both a cyclic carbonate and a chain ester are included.
The term “chain ester” is used as a concept including a chain carbonate and a chain carboxylic acid ester.
Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 4-fluoro-1,3-dioxolan-2-one (FEC), trans or Cis-4,5-difluoro-1,3-dioxolan-2-one (hereinafter collectively referred to as “DFEC”), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), and 4-ethynyl-1 , 3-dioxolan-2-one (EEC).
Among these, it is preferable to use at least one of a carbon-carbon double bond or a cyclic carbonate having a fluorine atom because the high-temperature cycle characteristics are further improved, and a cyclic carbonate having a carbon-carbon double bond and a cyclic having a fluorine atom are preferred. More preferably, both carbonates are included. As the cyclic carbonate having a carbon-carbon double bond, VC and VEC are more preferable, and as the cyclic carbonate having a fluorine atom, FEC and DFEC are more preferable.

The content of the cyclic carbonate having a carbon-carbon double bond is preferably 0.07% by volume or more, more preferably 0.2% by volume or more, still more preferably 0.7% by volume based on the total volume of the nonaqueous solvent. More than 7% by volume, and the upper limit is preferably 7% by volume or less, more preferably 4% by volume or less, and still more preferably 2.5% by volume or less, and the stability of the coating during a high temperature cycle can be further increased. Therefore, it is preferable.
The content of the cyclic carbonate having a fluorine atom is preferably 0.07% by volume or more, more preferably 4% by volume or more, and still more preferably 7% by volume or more with respect to the total volume of the nonaqueous solvent. Is preferably 35% by volume or less, more preferably 25% by volume or less, and still more preferably 15% by volume or less, since the stability of the coating during a high temperature cycle can be further increased.
When the non-aqueous solvent contains both a cyclic carbonate having a carbon-carbon double bond and a cyclic carbonate having a fluorine atom, the content of the cyclic carbonate having a carbon-carbon double bond relative to the content of the cyclic carbonate having a fluorine atom Is preferably 0.2% by volume or more, more preferably 3% by volume or more, and further preferably 7% by volume or more. The upper limit is preferably 40% by volume or less, more preferably 30% by volume or less, and still more preferably Is preferably 15% by volume or less because the stability of the coating film during a high temperature cycle can be further increased.
Moreover, since the resistance of the film formed on an electrode becomes small when a nonaqueous solvent contains both ethylene carbonate, propylene carbonate, or both ethylene carbonate and propylene carbonate, it is preferable. The content of ethylene carbonate, propylene carbonate, or both ethylene carbonate and propylene carbonate is preferably at least 3% by volume, more preferably at least 5% by volume, even more preferably at least 7% by volume, based on the total volume of the nonaqueous solvent. Moreover, as an upper limit, Preferably it is 45 volume% or less, More preferably, it is 35 volume% or less, More preferably, it is 25 volume% or less.

These solvents may be used alone, and when two or more solvents are used in combination, the electrochemical properties at high temperatures are further improved, and it is particularly preferable to use a combination of three or more solvents.
Preferred combinations of these cyclic carbonates include EC and PC, EC and VC, PC and VC, VC and FEC, EC and FEC, PC and FEC, FEC and DFEC, EC and DFEC, PC and DFEC, VC and DFEC , VEC and DFEC, EC and PC and VC, EC and PC and FEC, EC and VC and FEC, EC and VC and VEC, PC and VC and FEC, EC and VC and DFEC, PC and VC and DFEC, EC and PC And VC, FEC, EC, PC, VC, DFEC and the like are preferable. Of the above combinations, EC and VC, EC and FEC, PC and FEC, EC and PC and VC, EC and PC and FEC, EC and VC and FEC, PC and VC and FEC, EC and PC and VC and FEC, etc. The combination of is more preferable.

Examples of chain esters include asymmetric chain carbonates such as methyl ethyl carbonate (MEC), methyl propyl carbonate (MPC), methyl isopropyl carbonate (MIPC), methyl butyl carbonate, and ethyl propyl carbonate, dimethyl carbonate (DMC), and diethyl carbonate ( DEC), symmetric chain carbonates such as dipropyl carbonate and dibutyl carbonate, pivalate esters such as methyl pivalate, ethyl pivalate, and propyl pivalate, chains such as methyl propionate, ethyl propionate, methyl acetate, and ethyl acetate Preferred examples include carboxylic acid esters.
When using a negative electrode whose charging potential in a fully charged state is less than 1 V on the basis of Li, among the chain esters, dimethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, methyl propionate, acetic acid A chain ester having a methyl group selected from methyl and ethyl acetate is preferable, and a chain carbonate having a methyl group is particularly preferable. This is because decomposition at the negative electrode hardly proceeds and capacity deterioration can be suppressed.
Moreover, when using the chain carbonate which has a methyl group, it is preferable to use 2 or more types. Further, it is more preferable that both a symmetric chain carbonate and an asymmetric chain carbonate are contained, and it is further more preferable that the content of the symmetric chain carbonate is more than that of the asymmetric chain carbonate.

The content of the chain ester is not particularly limited, but it is preferably used in the range of 60 to 90% by volume with respect to the total volume of the nonaqueous solvent. If the content is 60% by volume or more, the viscosity of the non-aqueous electrolyte does not become too high, and if it is 90% by volume or less, the electrical conductivity of the non-aqueous electrolyte decreases and the electrochemical properties at high temperature decrease. Since there is little possibility of doing, it is preferable that it is the said range.
Moreover, when using chain carbonate, it is preferable to use 2 or more types. Further, it is more preferable that both a symmetric chain carbonate and an asymmetric chain carbonate are contained, and it is more preferable that the content of the symmetric chain carbonate is more than that of the asymmetric chain carbonate.
The volume ratio of the symmetric chain carbonate in the chain carbonate is preferably 51% by volume or more, and more preferably 55% by volume or more. As an upper limit, 95 volume% or less is more preferable, and it is still more preferable in it being 85 volume% or less. It is particularly preferred that the symmetric chain carbonate contains dimethyl carbonate. The asymmetric chain carbonate preferably has a methyl group, and methyl ethyl carbonate is particularly preferable.
The above case is preferable because the electrochemical characteristics at a higher temperature are further improved.
The ratio between the cyclic carbonate and the chain ester is preferably 10:90 to 45:55, and preferably 15:85 to 40:60, from the viewpoint of improving electrochemical properties at high temperatures. More preferably, 20:80 to 35:65 is particularly preferable.

  Other non-aqueous solvents include tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 1,3-dioxane, cyclic ethers such as 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxy. One or two selected from chain ethers such as ethane, 1,2-dibutoxyethane, amides such as dimethylformamide, sulfones such as sulfolane, lactones such as γ-butyrolactone, γ-valerolactone, and α-angelicalactone The above is preferably mentioned.

[Electrolyte salt]
Preferred examples of the electrolyte salt used in the present invention include the following lithium salts and onium salts.
(Lithium salt)
Examples of the lithium salt include inorganic lithium salts such as LiPF ₆ , LiPO ₂ F ₂ , Li ₂ PO ₃ F, LiBF ₄ , LiClO ₄ , FSO ₃ Li, LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiCF ₃ SO ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiPF ₄ (CF ₃ ) ₂ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (iso-C) ₃ F ₇ ) ₃ , LiPF ₅ (iso-C ₃ F ₇ ) and other lithium salts containing a chain-like fluorinated alkyl group, (CF ₂ ) ₂ (SO ₂ ) ₂ NLi, (CF ₂ ) ₃ ( SO ₂ ) ₂ Lithium salt having a cyclic fluorinated alkylene chain such as NLi, bis [oxalate-O, O ′] lithium borate, difluoro [oxalate-O, O ′] lithium borate, difluorobis [oxalate-O , O '] lithium phosphate Fine tetrafluoro [oxalate -O, O '] lithium salt having an anion oxalate complexes of lithium phosphate and the like are suitably exemplified, can be used as a mixture alone or in combination.
Among these, LiPF ₆ , LiPO ₂ F ₂ , Li ₂ PO ₃ F, LiBF ₄ , FSO ₃ Li, LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ F ) ₂ , one or two selected from lithium bis [oxalate-O, O ′] lithium borate, difluorobis [oxalate-O, O ′] lithium phosphate, and tetrafluoro [oxalate-O, O ′] lithium phosphate More than species are preferred, LiPF ₆ , LiPO ₂ F ₂ , FSO ₃ Li, LiBF ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ F) ₂ and difluorobis [oxalate-O, O ′] lithium phosphate 1 type, or 2 or more types selected from are more preferable. The concentration of the lithium salt is usually preferably 0.3 M or more, more preferably 0.7 M or more, and further preferably 1.1 M or more with respect to the non-aqueous solvent. Moreover, the upper limit is preferably 2.5M or less, more preferably 2.0M or less, and still more preferably 1.6M or less.
Further, a suitable combination of these lithium salts includes LiPF ₆ , and further includes LiPO ₂ F ₂ , FSO ₃ Li, LiBF ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ F) ₂ , bis [ More preferably, it contains one or more selected from lithium oxalate-O, O ′] lithium borate and difluorobis [oxalate-O, O ′] lithium phosphate.
When the proportion of lithium salt other than LiPF _{6 in the} non-aqueous solvent is 0.001M or more, the effect of improving electrochemical characteristics at high temperatures is easily exhibited, and when it is 0.005M or less, electrochemical characteristics at high temperatures. This is preferable because there is little concern that the effect of improving the resistance will decrease. Preferably it is 0.01M or more, Especially preferably, it is 0.03M or more, Most preferably, it is 0.04M or more. The upper limit is preferably 0.4M or less, particularly preferably 0.2M or less.
When the non-aqueous electrolyte contains LiPF ₆ , the ratio of the molar concentration of the lithium salt of the present invention to LiPF ₆ is 0.0005 or more, and the effect of improving electrochemical properties at high temperatures is easily exhibited. The following is preferable because there is little possibility that the improvement effect of electrochemical characteristics at high temperature is lowered. The lower limit is more preferably 0.001 or more, and still more preferably 0.005 or more. Moreover, the upper limit is more preferably 0.2 or less, and still more preferably 0.1 or less.

(Onium salt)
Moreover, as an onium salt, the various salts which combined the onium cation and anion shown below are mentioned suitably.
Specific examples of the onium cation include tetramethylammonium cation, ethyltrimethylammonium cation, diethyldimethylammonium cation, triethylmethylammonium cation, tetraethylammonium cation, N, N-dimethylpyrrolidinium cation, N-ethyl-N-methylpyrrole. Dinium cation, N, N-diethylpyrrolidinium cation, spiro- (N, N ′)-bipyrrolidinium cation, N, N′-dimethylimidazolinium cation, N-ethyl-N′-methylimidazoli Preferable examples include nium cation, N, N′-diethylimidazolinium cation, N, N′-dimethylimidazolium cation, N-ethyl-N′-methylimidazolium cation, and N, N′-diethylimidazolium cation. Is The
Specific examples of anions include PF ₆ anion, BF ₄ anion, ClO ₄ anion, AsF ₆ anion, CF ₃ SO ₃ anion, N (CF ₃ SO ₂ ) ₂ anion, N (C ₂ F ₅ SO ₂ ) ₂ anion. , Etc. are mentioned suitably.
These onium salts can be used singly or in combination of two or more.

[Production of non-aqueous electrolyte]
The non-aqueous electrolyte of the present invention is, for example, mixed with the non-aqueous solvent, and added thereto the dihalophosphate compound represented by the general formula (I) with respect to the electrolyte salt and the non-aqueous electrolyte. Can be obtained.
At this time, it is preferable that the compound added to the non-aqueous solvent and the non-aqueous electrolyte to be used is one that is purified in advance and has as few impurities as possible within a range that does not significantly reduce the productivity.

  The nonaqueous electrolytic solution of the present invention can be used in the following first to fourth power storage devices, and not only a liquid but also a gelled one can be used as the nonaqueous electrolyte. Furthermore, the non-aqueous electrolyte of the present invention can be used for a solid polymer electrolyte. In particular, it is preferably used for the first electricity storage device (that is, for a lithium battery) or the fourth electricity storage device (that is, for a lithium ion capacitor) that uses a lithium salt as an electrolyte salt, and is used for a lithium battery. More preferably, it is most suitable for use as a lithium secondary battery.

[First power storage device (lithium battery)]
In this specification, the lithium battery is a general term for a lithium primary battery and a lithium secondary battery. In this specification, the term lithium secondary battery is used as a concept including a so-called lithium ion secondary battery. The lithium battery of the present invention comprises the nonaqueous electrolyte solution in which an electrolyte salt is dissolved in a positive electrode, a negative electrode, and a nonaqueous solvent. Components other than the non-aqueous electrolyte, such as a positive electrode and a negative electrode, can be used without particular limitation.
For example, as the positive electrode active material for a lithium secondary battery, a composite metal oxide with lithium containing at least one selected from cobalt, manganese, and nickel is used. These positive electrode active materials can be used individually by 1 type or in combination of 2 or more types.
Examples of such lithium composite metal oxides include LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiCo _1-x Ni _x O ₂ (0.01 <x <1), LiCo _1/3 Ni _1/3. One type or two or more types selected from Mn _1/3 O ₂ , LiNi _1/2 Mn _3/2 O ₄ , and LiCo _0.98 Mg _0.02 O ₂ may be mentioned. Further, LiCoO ₂ and LiMn ₂ O ₄ , LiCoO ₂ and LiNiO ₂ , LiMn ₂ O ₄ and LiNiO ₂ may be used in combination.

In addition, in order to improve safety and cycle characteristics during overcharge, or to enable use at a charging potential of 4.3 V or higher, a part of the lithium composite metal oxide may be substituted with another element. . For example, a part of cobalt, manganese, nickel is replaced with at least one element such as Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, Cu, Bi, Mo, La, A part of O can be substituted with S or F, or a compound containing these other elements can be coated.
Among these, lithium composite metal oxides such as LiCoO ₂ , LiMn ₂ O ₄ , and LiNiO ₂ that can be used at a charged potential of the positive electrode in a fully charged state of 4.3 V or more on the basis of Li are preferable, and LiCo _1-x M _x O ₂ (wherein M is one or more elements selected from Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, Cu, 0.001 ≦ x ≦ 0.05) ), LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , LiNi _0.5 Mn _0.3 Co _0.2 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _1/2 Mn _3/2 O ₄ , Li ₂ MnO ₃ And LiMO ₂ (M is a transition metal such as Co, Ni, Mn, Fe, etc.) and more preferably a lithium composite metal oxide usable at 4.4 V or higher. When a lithium composite metal oxide that operates at a high charging voltage is used, the electrochemical characteristics at high temperatures are likely to be deteriorated due to the reaction with the electrolyte during charging. However, in the lithium secondary battery according to the present invention, these electrochemical properties are reduced. The deterioration of characteristics can be suppressed.

When the pH of the supernatant obtained when 10 g of the positive electrode active material is dispersed in 100 ml of distilled water is 10.0 to 12.5, it is preferable because high-temperature cycle characteristics can be easily obtained, and further 10.5 to 12 0.0 is preferred.
In addition, when Ni is included as an element in the positive electrode, since impurities such as LiOH in the positive electrode active material tend to increase, it is preferable because higher temperature cycle characteristics are easily obtained, and the atomic concentration of Ni in the positive electrode active material is preferable. The case where it is 5-25 atomic% is still more preferable, and the case where it is 8-21 atomic% is especially preferable.

Furthermore, lithium-containing olivine-type phosphate can also be used as the positive electrode active material. In particular, lithium-containing olivine-type phosphate containing one or more selected from iron, cobalt, nickel and manganese is preferable. Specific examples thereof include LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , LiMnPO _{4 and the} like.
Some of these lithium-containing olivine-type phosphates may be substituted with other elements, and some of iron, cobalt, nickel, and manganese are replaced with Co, Mn, Ni, Mg, Al, B, Ti, V, and Nb. , Cu, Zn, Mo, Ca, Sr, W and Zr can be substituted by one or more elements selected from these, or can be coated with a compound or carbon material containing these other elements. Among these, LiFePO ₄ or LiMnPO ₄ is preferable.
Moreover, lithium containing olivine type | mold phosphate can also be mixed with the said positive electrode active material, for example, and can be used.

As the positive electrode for lithium primary _{battery, CuO, Cu 2 O, Ag} 2 O, Ag 2 CrO 4, CuS, CuSO 4, TiO 2, TiS 2, SiO 2, SnO, V 2 O 5, V 6 O 12 , VO _x , Nb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ Pb ₂ O ₅ , Sb ₂ O ₃ , CrO ₃ , Cr ₂ O ₃ , MoO ₃ , WO ₃ , SeO ₂ , MnO ₂ , Mn ₂ O ₃ , Fe ₂ O ₃ , FeO, Fe ₃ O ₄ , Ni ₂ O ₃ , NiO, CoO ₃ , CoO and the like, oxides of one or more metal elements or chalcogen compounds, sulfur such as SO ₂ and SOCl ₂ Examples thereof include compounds, and fluorocarbons (fluorinated graphite) represented by the general formula (CF _x ) _n . Among these, MnO ₂ , V ₂ O ₅ , graphite fluoride and the like are preferable.

  The conductive agent for the positive electrode is not particularly limited as long as it is an electron conductive material that does not cause a chemical change. For example, graphite such as natural graphite (flaky graphite, etc.), graphite such as artificial graphite, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, or one or more carbon blacks can be used. . Further, graphite and carbon black may be appropriately mixed and used. 1-10 mass% is preferable and, as for the addition amount to the positive mix of a electrically conductive agent, 2-5 mass% is especially preferable.

The positive electrode is composed of a conductive agent such as acetylene black and carbon black, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of styrene and butadiene (SBR), acrylonitrile and butadiene. Mixing with a binder such as copolymer (NBR), carboxymethyl cellulose (CMC), ethylene propylene diene terpolymer, etc., and adding a high boiling point solvent such as 1-methyl-2-pyrrolidone to knead and mix Then, this positive electrode mixture was applied to a current collector aluminum foil, a stainless steel lath plate, etc., dried and pressure-molded, and then subjected to vacuum at a temperature of about 50 ° C. to 250 ° C. for about 2 hours. It can be manufactured by heat treatment.
The density of the part except the collector of the positive electrode is usually at 1.5 g / cm ³ or more, to further enhance the capacity of the battery, is preferably 2 g / cm ³ or more, more preferably, 3 g / cm ³ It is above, More preferably, it is 3.6 g / cm ³ or more. In addition, as an upper limit, 4 g / cm < ³ > or less is preferable.

Examples of the negative electrode active material for a lithium secondary battery include lithium metal, lithium alloy, and a carbon material capable of occluding and releasing lithium (easily graphitized carbon and a (002) plane spacing of 0.37 nm or more). Non-graphitizable carbon, graphite with (002) plane spacing of 0.34 nm or less, etc.], tin (single), tin compound, silicon (single), silicon compound, lithium titanate such as Li ₄ Ti ₅ O ₁₂ A compound etc. can be used individually by 1 type or in combination of 2 or more types.
Among these, in terms of the ability to occlude and release lithium ions, it is more preferable to use a highly crystalline carbon material such as artificial graphite and natural graphite, and the lattice spacing (d ₀₀₂ ) of the lattice plane ( ₀₀₂ ) is 0. It is particularly preferable to use a carbon material having a graphite-type crystal structure of 340 nm (nanometer) or less, particularly 0.335 to 0.337 nm.
Artificial graphite particles having a massive structure in which a plurality of flat graphite fine particles are assembled or bonded non-parallel to each other, for example, scaly natural graphite particles are repeatedly given mechanical action such as compression force, friction force, shear force, By using graphite particles that have been subjected to spheroidization treatment, the density of the portion excluding the current collector of the negative electrode can be obtained from X-ray diffraction measurement of the negative electrode sheet when pressure-molded to a density of 1.5 g / cm ³ or more. Electrochemistry at higher temperatures when the ratio I (110) / I (004) of the peak intensity I (110) of the (110) plane and the peak intensity I (004) of the (004) plane of the graphite crystal is 0.01 or more. It is preferable because the characteristics are improved, more preferably 0.05 or more, and still more preferably 0.1 or more. In addition, since the crystallinity may be lowered due to excessive treatment and the discharge capacity of the battery may be lowered, the upper limit of the peak intensity ratio I (110) / I (004) is preferably 0.5 or less. 3 or less is more preferable.
In addition, it is preferable that the highly crystalline carbon material (core material) is coated with a carbon material having a lower crystallinity than the core material because electrochemical characteristics at a high temperature are further improved. The crystallinity of the carbon material of the coating can be confirmed by TEM.
When a highly crystalline carbon material is used, it reacts with the non-aqueous electrolyte during charging and tends to lower the electrochemical characteristics at high temperatures due to an increase in interfacial resistance, but the lithium secondary battery according to the present invention has a high temperature. The electrochemical properties of the are improved.

  Examples of the metal compound capable of inserting and extracting lithium as the negative electrode active material include Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, and Cu. , Zn, Ag, Mg, Sr, Ba, and other compounds containing at least one metal element. These metal compounds may be used in any form such as a simple substance, an alloy, an oxide, a nitride, a sulfide, a boride, and an alloy with lithium, but any of a simple substance, an alloy, an oxide, and an alloy with lithium. Is preferable because the capacity can be increased. Among these, those containing at least one element selected from Si, Ge and Sn are preferable, and those containing at least one element selected from Si and Sn are more preferable because the capacity of the battery can be increased.

The negative electrode is kneaded using the same conductive agent, binder, and high-boiling solvent as in the production of the positive electrode, and then the negative electrode mixture is applied to the copper foil of the current collector. After being dried and pressure-molded, it can be produced by heat treatment under vacuum at a temperature of about 50 ° C. to 250 ° C. for about 2 hours.
The density of the portion excluding the current collector of the negative electrode is usually 1.1 g / cm ³ or more, and is preferably 1.5 g / cm ³ or more, more preferably 1.7 g, in order to further increase the capacity of the battery. / Cm ³ or more. In addition, as an upper limit, 2 g / cm < ³ > or less is preferable.

  Moreover, lithium metal or a lithium alloy is mentioned as a negative electrode active material for lithium primary batteries.

The structure of the lithium battery is not particularly limited, and a coin-type battery, a cylindrical battery, a square battery, a laminated battery, or the like having a single-layer or multi-layer separator can be applied.
Although there is no restriction | limiting in particular as a separator for batteries, The single layer or laminated microporous film of polyolefin, such as a polypropylene and polyethylene, a woven fabric, a nonwoven fabric, etc. can be used.

  The lithium secondary battery in the present invention has excellent electrochemical characteristics at high temperatures even when the end-of-charge voltage is 4.2 V or higher, particularly 4.3 V or higher, and also has excellent electrochemical characteristics at 4.4 V or higher. is there. The end-of-discharge voltage is usually 2.8 V or more, and further 2.5 V or more, but the lithium secondary battery in the present invention can be 2.0 V or more. Although it does not specifically limit about an electric current value, Usually, it uses in the range of 0.1-30C. Moreover, the lithium battery in this invention can be charged / discharged at -40-100 degreeC, Preferably it is -10-80 degreeC.

  In the present invention, as a countermeasure against an increase in the internal pressure of the lithium battery, a method of providing a safety valve on the battery lid or cutting a member such as a battery can or a gasket can be employed. Further, as a safety measure for preventing overcharge, the battery lid can be provided with a current interruption mechanism that senses the internal pressure of the battery and interrupts the current.

[Second power storage device (electric double layer capacitor)]
It is an electricity storage device that stores energy by using the electric double layer capacity at the interface between the electrolyte and the electrode. An example of the present invention is an electric double layer capacitor. The most typical electrode active material used for this electricity storage device is activated carbon. Double layer capacity increases roughly in proportion to surface area.

[Third power storage device]
It is an electrical storage device which stores energy using dope / dedope reaction of an electrode. Examples of the electrode active material used in this power storage device include metal oxides such as ruthenium oxide, iridium oxide, tungsten oxide, molybdenum oxide, and copper oxide, and π-conjugated polymers such as polyacene and polythiophene derivatives. Capacitors using these electrode active materials can store energy associated with electrode doping / dedoping reactions.

[Fourth storage device (lithium ion capacitor)]
It is an electricity storage device that stores energy by utilizing lithium ion intercalation with a carbon material such as graphite as a negative electrode. It is called a lithium ion capacitor (LIC). Examples of the positive electrode include those using an electric double layer between an activated carbon electrode and an electrolytic solution, and those using a π-conjugated polymer electrode doping / dedoping reaction. The electrolyte contains at least a lithium salt such as LiPF ₆ .

[Dihalophosphate compound]
The dihalophosphate compound which is a novel compound of the present invention is represented by the following general formula (IV).
A dihalophosphate compound represented by the following general formula (IV).

Wherein R ¹³ and R ¹⁴ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryloxy having 6 to 12 carbon atoms. Represents a group, X ⁴ represents a fluorine atom or a chlorine atom, and p represents 1 or 2.
R ¹⁵ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms when p is 1. When p is 2, an alkylene group having 2 to 6 carbon atoms, an alkenylene group having 4 to 8 carbon atoms, or an alkynylene group having 4 to 8 carbon atoms is shown.
At least one hydrogen atom of the group represented by R ¹³ or R ¹⁴ may be substituted with a halogen atom. When R ¹³ and R ¹⁴ are an alkyl group or an alkoxy group, R ¹³ and R ¹⁴ may be bonded to form a ring structure. However, R ¹³ and R ¹⁴ are both an alkoxy group having 1 to 6 carbon atoms, and R ¹⁵ is an alkyl group having 1 to 2 carbon atoms. )
Specific examples and preferred examples of R ¹³ , R ¹⁴ , R ¹⁵ , X ⁴ , and p in the general formula (IV) are R ¹ , R ² , R ³ , X ¹ and m corresponding to the general formula (I). Is the same as each. In addition, specific examples and preferred examples of the dihalophosphate compound represented by the general formula (IV) exclude the case where both of X ¹ and X ² of the dihalophosphate compound represented by the general formula (I) are chlorine atoms. It is the same as a specific example and a suitable example.

The dihalophosphate compound of the present invention can be synthesized by the following methods (a) to (c), but is not limited to these methods.
(A) A method in which an organophosphorus carboxylic acid halide and a corresponding hydroxy compound are esterified in the presence or absence of a solvent and in the presence or absence of a base (hereinafter also referred to as “method (a)”).
(B) A method in which an organophosphorus carboxylic acid and a corresponding hydroxy compound are condensed in the presence or absence of a solvent and in the presence of an acid catalyst or a dehydrating agent (hereinafter also referred to as “method (b)”).
(C) A method of transesterifying an organophosphorus carboxylic acid ester and the corresponding hydroxy compound in the presence or absence of a solvent and in the presence of a catalyst (hereinafter also referred to as “(c) method”).

[(A) method]
Method (a) is a method in which an organophosphorus carboxylic acid halide and the corresponding hydroxy compound are esterified in the presence or absence of a solvent and in the presence or absence of a base. The raw material organophosphorus carboxylic acid halide can be synthesized by an existing general-purpose method. For example, it can be synthesized by a method of reacting an organophosphorus carboxylic acid and thionyl chloride described in Organic Letters, 6, (20), p3477 (2004).
In the reaction of the method (a), the amount of the hydroxy compound used is preferably 0.8 to 20 mol, more preferably 0.9 to 10 mol, and further preferably 1 to 5 with respect to 1 mol of the organophosphorus carboxylic acid halide. Is a mole.
(A) As a hydroxy compound used as the method, methanol, ethanol, propanol, butanol, hexanol, isopropanol, cyclohexanol, 2-propyn-1-ol, 3-butyn-2-ol, 2-methyl-3- Butyn-2-ol, 2-butyne-1,4-diol, 3-hexyne-2,5-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 2-trifluoromethylphenol, 3 -Trifluoromethylphenol, 4-trifluoromethylphenol, pentafluorophenol and the like.

In the reaction of the method (a), the reaction proceeds without solvent, but a solvent can be used if it is inert to the reaction. Solvents used are aliphatic hydrocarbons such as heptane and cyclohexane, halogenated hydrocarbons such as dichloromethane and dichloroethane, aromatic hydrocarbons such as toluene and xylene, halogenated aromatic hydrocarbons such as chlorobenzene and fluorobenzene, diisopropyl Ethers such as ether, dioxane and dimethoxyethane, esters such as ethyl acetate, butyl acetate, dimethyl carbonate and diethyl carbonate, nitriles such as acetonitrile and propionitrile, sulfoxides such as dimethyl sulfoxide and sulfolane, N, N-dimethylformamide, N , N-dimethylacetamide and the like, or a mixture thereof. Among these, aliphatic or aromatic hydrocarbons such as heptane, cyclohexane, toluene, ethyl acetate, dimethyl carbonate, and esters are preferable.
The amount of the solvent used is preferably 0 to 30 parts by mass, more preferably 1 to 10 parts by mass with respect to 1 part by mass of the organophosphorus carboxylic acid halide.

In the reaction of the method (a), the reaction proceeds in the absence of a base, but the presence of a base is preferable because the reaction is promoted. As the base, both inorganic bases and organic bases can be used.
Inorganic bases include potassium carbonate, sodium carbonate, calcium hydroxide, and calcium oxide. Organic bases include linear or branched aliphatic tertiary amines, unsubstituted or substituted imidazoles, pyridines, pyrimidines, among which trimethylamine, triethylamine, tripropylamine, tributylamine, diisopropyl Trialkylamines such as pluethylamine and pyridines such as pyridine and N, N-dimethylaminopyridine are preferred.
The amount of the base used is preferably 0.8 to 5 mol, more preferably 1 to 3 mol, and still more preferably 1 to 1.5 mol, with respect to 1 mol of the organophosphorus carboxylic acid halide.

In the reaction of the method (a), the lower limit of the reaction temperature is preferably −20 ° C. or higher, more preferably −10 ° C. or higher, from the viewpoint of not reducing the reactivity. From the viewpoint of suppressing side reactions and product decomposition, the upper limit of the reaction temperature is preferably 100 ° C. or less, and more preferably 80 ° C. or less.
In addition, the reaction time can be appropriately changed depending on the reaction temperature and scale, but if the reaction time is too short, unreacted substances remain, and conversely if the reaction time is too long, there is a risk of decomposition of the reaction product or side reaction. , Preferably 0.1 to 12 hours, more preferably 0.2 to 6 hours.

[(B) method]
Method (b) is a method in which an organophosphorus carboxylic acid and a corresponding hydroxy compound are condensed in the presence or absence of a solvent and in the presence of an acid catalyst or a dehydrating agent.
In the reaction of the method (b), the amount of the hydroxy compound used is preferably 0.8 to 20 mol, more preferably 0.9 to 10 mol, still more preferably 1 to 5 mol, relative to 1 mol of the organophosphorus carboxylic acid. It is.
Examples of the hydroxy compound used in the method (b) include the hydroxy compounds described in the method (a).

In the reaction of method (b), the reaction proceeds without solvent, but a solvent can be used if it is inert to the reaction. Examples of the solvent used include aliphatic hydrocarbons, halogenated hydrocarbons, aromatic hydrocarbons, halogenated aromatic hydrocarbons, ethers, nitriles, sulfoxides, and mixtures thereof described in the method (a). Among these, aliphatic or aromatic hydrocarbons such as heptane, cyclohexane, and toluene that are difficult to mix with water are preferable.
The amount of the solvent used is preferably 0 to 30 parts by mass, more preferably 1 to 10 parts by mass with respect to 1 part by mass of the organophosphorus carboxylic acid.

In the method (b), when an acid catalyst is used, the acid catalyst that can be used includes mineral acids such as sulfuric acid and phosphoric acid, sulfonic acids such as paratoluenesulfonic acid, methanesulfonic acid, and trifluoromethanesulfonic acid, and trifluoro Examples include boric acid, Lewis acids such as tetraisopropoxytitanium, solid acids such as zeolite and acidic resin, or mixed acids thereof. Among these, paratoluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, etc. Lewis acids such as sulfonic acid and tetraisopropoxy titanium are preferred. The amount of the catalyst used is preferably 0.001 to 5 mol, more preferably 0.01 to 1 mol, and still more preferably 0.01 to 1 mol of the organophosphorus carboxylic acid from the viewpoint of suppressing side reactions. ~ 0.3 mol.
When a dehydrating agent is used, usable dehydrating agents are dicyclohexylcarbodiimide, N, N′-carbonyldiimidazole, di-2-pyridyl carbonate, phenyldichlorophosphate, a mixture of ethyl diethylazodicarboxylate and triphenylphosphine, and the like. One or more types may be selected. The amount of the dehydrating agent to be used is preferably 0.8 to 10 mol, more preferably 0.9 to 5 mol, and still more preferably 1 to 3 mol with respect to 1 mol of the organophosphorus carboxylic acid.

In the reaction of the method (b), the lower limit of the reaction temperature when using an acid catalyst is preferably 0 ° C. or higher, and more preferably 20 ° C. or higher from the viewpoint of not reducing the reactivity. Further, from the viewpoint of suppressing side reactions and product decomposition, the upper limit of the reaction temperature is preferably 200 ° C. or less, and more preferably 150 ° C. or less.
Further, the lower limit of the reaction temperature when using the dehydrating agent is preferably −20 ° C. or higher, and more preferably 0 ° C. or higher from the viewpoint of not reducing the reactivity. From the viewpoint of suppressing side reactions and product decomposition, the upper limit of the reaction temperature is preferably 100 ° C. or lower, more preferably 50 ° C. or lower.
The reaction time of the method (b) can be appropriately changed depending on the reaction temperature and scale, but if the reaction time is too short, unreacted substances remain. Conversely, if the reaction time is too long, there is a risk of decomposition of the reaction product or side reaction. Therefore, it is preferably 0.1 to 24 hours, and more preferably 0.2 to 12 hours.

[(C) method]
Method (c) is a method in which an organophosphorus carboxylic acid ester and a corresponding hydroxy compound are transesterified in the presence or absence of a solvent and in the presence of a catalyst.
In the reaction of the method (c), the amount of the hydroxy compound used is preferably 0.9 to 20 mol, more preferably 1 to 15 mol, still more preferably 1 to 8 mol, relative to 1 mol of the organophosphorus carboxylic acid. .
Examples of the hydroxy compound used in the method (c) include the hydroxy compounds described in the method (a).

In the reaction of the method (c), the reaction proceeds without solvent, but a solvent can be used if it is inert to the reaction. Examples of the solvent used include aliphatic hydrocarbons, halogenated hydrocarbons, aromatic hydrocarbons, halogenated aromatic hydrocarbons, ethers, nitriles, sulfoxides, and mixtures thereof described in the method (a). Among these, aliphatic or aromatic hydrocarbons such as heptane, cyclohexane, and toluene that are difficult to mix with water are preferable.
The amount of the solvent used is preferably 0 to 30 parts by mass, more preferably 1 to 10 parts by mass with respect to 1 part by mass of the organophosphorus carboxylic acid ester.

  In the method (c), either an acid catalyst or a base catalyst can be used as the catalyst used. Examples of the acid catalyst used include mineral acids such as sulfuric acid and phosphoric acid, sulfonic acids such as paratoluenesulfonic acid, methanesulfonic acid, and trifluoromethanesulfonic acid, trifluoroboric acid, tetraethoxytitanium, and tetraisopropoxytitanium. Examples include Lewis acids, zeolites, solid acids such as acidic resins, and mixed acids thereof. Among these, Lewis acids such as tetraethoxy titanium and tetraisopropoxy titanium are preferable. Examples of the base used include alkali metal carbonates such as sodium carbonate and potassium carbonate, alkali metal alcoholates such as sodium methylate, sodium ethylate and potassium tert-butoxide, and alkali metal hydrogens such as sodium hydride and potassium hydride. And alkali metals such as sodium, potassium and lithium, or mixtures thereof. Among these, alkali metal carbonates such as sodium carbonate and potassium carbonate are preferred. The amount of the catalyst used is preferably 0.001 to 5 mol, more preferably 0.005 to 1 mol, and still more preferably 0.01 to 0.3 mol, relative to 1 mol of the organophosphorus carboxylic acid ester. If present, side reactions can be suppressed, which is preferable.

  In the reaction of the method (c), the lower limit of the reaction temperature is preferably 0 ° C. or higher, and more preferably 20 ° C. or higher so as not to lower the reactivity. The upper limit of the reaction is preferably 200 ° C. or lower, and more preferably 150 ° C. or lower in order to suppress side reactions and product decomposition. The reaction time depends on the reaction temperature and scale. However, if the reaction time is too short, unreacted substances remain. Conversely, if the reaction time is too long, side reactions and decomposition of the product tend to proceed. 1 to 24 hours, more preferably 0.2 to 15 hours.

  Examples of synthesis of dihalophosphate compounds used in the present invention and examples of non-aqueous electrolytes of the present invention using dihalophosphate compounds are shown below, but the present invention is limited to these synthesis examples and examples. It is not something.

Synthesis Example 1 [Synthesis of 2-propynyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate]
Ethyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate 10.0 g (38.0 mmol), propargyl alcohol 43.1 g (76.9 mol) and tetraethyl titanate 0.88 g (4.0 mmol) at room temperature added. The mixture was heated to reflux at 100 ° C. for 24 hours, and 21 mL of ethanol and 42 mL of propargyl alcohol were distilled off under reduced pressure. Thereafter, 10 g of water was added, the resulting solid was filtered, and the solvent was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (ethyl acetate / hexane = 1/5 elution), and the desired 2-propynyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate 4.2 g (40%) Got. The obtained 2-propynyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate was subjected to ¹ H-NMR measurement to confirm its structure.
The results are shown below.
[2-propynyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate]
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 4.91 (d, J = 2.5 Hz, 2H), 4.41-4.28 (m, 4H), 2.59 (t, J = 2) .5Hz, 1H), 1.43-1.35 (m, 6H)

Examples 1-30, Comparative Examples 1-2
[Production of lithium ion secondary battery]
LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ (the positive electrode active material, the pH of the supernatant liquid when 10 g of the positive electrode active material is dispersed in 100 ml of distilled water is 11.1); 94% by mass, acetylene black ( Conductive agent); 3% by mass is mixed and added to a solution in which polyvinylidene fluoride (binder); 3% by mass is previously dissolved in 1-methyl-2-pyrrolidone. Prepared. This positive electrode mixture paste was applied on both surfaces of an aluminum foil (current collector), dried and pressurized, and cut into a predetermined size to produce a positive electrode sheet. The density of the portion excluding the current collector of the positive electrode was 3.6 g / cm ³ .
Further, 95% by mass of artificial graphite (d ₀₀₂ = 0.335 nm, negative electrode active material) is added to a solution in which 5% by mass of polyvinylidene fluoride (binder) is dissolved in 1-methyl-2-pyrrolidone in advance. And mixed to prepare a negative electrode mixture paste. This negative electrode mixture paste was applied on both sides of a copper foil (current collector), dried and pressurized, and cut into a predetermined size to prepare a negative electrode sheet. The density of the portion excluding the current collector of the negative electrode was 1.5 g / cm ³ . As a result of X-ray diffraction measurement using this electrode sheet, the ratio of the peak intensity I (110) of the (110) plane of the graphite crystal to the peak intensity I (004) of the (004) plane [I (110) / I (004)] was 0.1.
Using the positive electrode sheet and negative electrode sheet obtained above and a separator made of a microporous polyethylene film, a nonaqueous electrolyte solution having the composition shown in Tables 1 to 3 was added to produce a 18650 type cylindrical battery.

[Evaluation of high-temperature cycle characteristics]
Using the battery produced by the above method, in a constant temperature bath at 60 ° C., it was charged with a constant current and a constant voltage of 1 C for 3 hours to a final voltage of 4.3 V, and then a discharge voltage of 3.0 V under a constant current of 1 C. Discharging until 1 cycle was repeated until 200 cycles were reached. And the discharge capacity maintenance factor after 60 degreeC 200 cycles was calculated | required with the following formula | equation.
Discharge capacity retention rate (%) = (discharge capacity after 200 cycles / discharge capacity after one cycle) × 100
Tables 1 to 3 show battery fabrication conditions and battery characteristics.

Example 31, Comparative Example 3
Instead of the negative electrode active material used in Example 3 and Comparative Example 1, a negative electrode sheet was prepared using silicon (single element) (negative electrode active material). Silicon (simple substance); 80% by mass, acetylene black (conductive agent); 15% by mass were mixed, and polyvinylidene fluoride (binder); 5% by mass was previously dissolved in 1-methyl-2-pyrrolidone. In addition to the solution, mixing was performed to prepare a negative electrode mixture paste. Example 1 and Comparative Example 1 except that this negative electrode mixture paste was applied onto a copper foil (current collector), dried and pressurized, and cut into a predetermined size to produce a negative electrode sheet. A cylindrical battery was prepared in the same manner as described above, and the battery was evaluated. The results are shown in Table 4.

Example 32, Comparative Example 4
A positive electrode sheet was prepared using LiFePO ₄ (positive electrode active material) coated with amorphous carbon instead of the positive electrode active material used in Example 3 and Comparative Example 1. LiFePO ₄ coated with amorphous carbon; 90% by mass, acetylene black (conductive agent); 5% by mass were mixed in advance, and polyvinylidene fluoride (binder); 5% by mass was added to 1-methyl-2-pyrrolidone. The positive electrode mixture paste was prepared by adding to and mixing with the solution previously dissolved in the mixture. This positive electrode mixture paste was applied onto an aluminum foil (current collector), dried, pressurized and cut into a predetermined size to produce a positive electrode sheet, and the charge termination voltage during battery evaluation was 3 A cylindrical battery was produced in the same manner as in Example 1 and Comparative Example 1, except that the discharge end voltage was set to 0.6 V and the discharge end voltage was set to 2.0 V, and the battery was evaluated. The results are shown in Table 5.

In any of the lithium secondary batteries of Examples 1 to 30, the triethylphosphonoacetate described in Comparative Example 1 and Patent Document 1 in which the dihalophosphate compound is not added in the nonaqueous electrolytic solution of the present invention was added. Compared with the lithium secondary battery of Comparative Example 2 which is a non-aqueous electrolyte, the cycle characteristics at a high temperature and particularly at a high charge voltage are remarkably improved. From the above, it was found that the effect of the present invention is a unique effect when the specific dihalophosphate compound of the present invention is contained in a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent. .
Further, from the comparison between Example 31 and Comparative Example 3 and from the comparison between Example 32 and Comparative Example 4, when silicon (single) Si is used for the negative electrode, or when lithium-containing olivine iron phosphate is used for the positive electrode Has the same effect. Therefore, it is clear that the effect of the present invention is not an effect dependent on a specific positive electrode or negative electrode.

  Furthermore, the non-aqueous electrolyte of the present invention also has an effect of improving the discharge characteristics at high temperatures of the lithium primary battery.

  If the non-aqueous electrolyte of the present invention is used, an electricity storage device having excellent electrochemical characteristics at high temperatures can be obtained. Particularly when used as a non-aqueous electrolyte for an electricity storage device mounted on a hybrid electric vehicle, a plug-in hybrid electric vehicle, a battery electric vehicle, or the like, it is possible to obtain an electricity storage device in which electrochemical characteristics at high temperatures are unlikely to deteriorate. .

Claims (18)

A nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains a dihalophosphate compound represented by the following general formula (I):

Wherein R ¹ and R ² 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 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, An alkenyloxy group having 2 to 6 carbon atoms, an alkynyloxy group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms, wherein X ¹ and X ² are each independently Represents a fluorine atom or a chlorine atom, and m represents 1 or 2.
R ³ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms when m is 1. When m is 2, an alkylene group having 2 to 6 carbon atoms, an alkenylene group having 4 to 8 carbon atoms, or an alkynylene group having 4 to 8 carbon atoms is shown.
At least one hydrogen atom of the group represented by R ¹ or R ² may be substituted with a halogen atom. When R ¹ and R ² are alkyl groups or alkoxy groups, R ¹ and R ² may be bonded to form a ring structure. ) The non-aqueous electrolyte further contains at least one selected from a compound represented by the following general formula (II) and a compound represented by the general formula (III).

(In the formula, R ⁴ and R ⁵ have the same meanings as R ¹ and R ² , and R ⁶ is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and an alkynyl group having 3 to 6 carbon atoms. Or an aryl group having 6 to 12 carbon atoms, R ⁷ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and X ³ represents a fluorine atom or a chlorine atom.
At least one hydrogen atom of the groups R ⁴ and R ⁵ may be substituted with a halogen atom. When R ⁴ and R ⁵ are an alkyl group or an alkoxy group, R ⁴ and R ⁵ may be bonded to form a ring structure. )

(Wherein R ⁸ and R ⁹ have the same meanings as R ¹ and R ² , R ¹⁰ has the same meaning as R ⁶ , R ¹¹ and R ¹² may be the same or different, and are a hydrogen atom or at least one 1 represents an alkyl group having 1 to 6 carbon atoms in which one hydrogen atom may be substituted with a halogen atom, and n represents an integer of 1 to 4. When R ⁸ and R ⁹ are an alkyl group or an alkoxy group, , R ⁸ and R ⁹ may combine to form a ring structure.)   The dihalophosphate compound represented by the general formula (I) is ethyl 2- (diethylphosphoryl) -2,2-difluoroacetate, 2-propynyl 2- (diethylphosphoryl) -2,2-difluoroacetate, ethyl 2 -(Ethoxy (ethyl) phosphoryl) -2,2-difluoroacetate, methyl 2- (dimethoxyphosphoryl) -2,2-difluoroacetate, methyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, ethyl 2- (Diethoxyphosphoryl) -2,2-difluoroacetate, ethyl 2-chloro-2- (diethoxyphosphoryl) -2-fluoroacetate, ethyl 2,2-dichloro-2- (diethoxyphosphoryl) acetate, ethyl 2- (Diphenoxyphosphoryl) -2,2-difluo Acetate, propyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, hexyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, isopropyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, Cyclohexyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, vinyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, allyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, 2- Propinyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, 2-propynyl 2,2-dichloro-2- (diethoxyphosphoryl) acetate, 1-methyl-2-propynyl 2- (diethoxyphosphoryl) -2 , 2-Difluoroacete , Pentafluorophenyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate, 2-trifluoromethyl 2- (diethoxyphosphoryl) -2,2-difluoroacetate , M = 2, ethane-1,2-diyl bis (2- (diethoxyphosphoryl) -2,2-difluoroacetate), 2-butene-1,4-diyl bis (2- (diethoxyphosphoryl) -2,2-difluoroacetate) or 2-butyne-1,4-diylbis (2- (diethoxyphosphoryl) -2,2-difluoroacetate) The non-aqueous electrolyte described.   The compound represented by the general formula (II) is ethyl 2- (diethylphosphoryl) -2-fluoroacetate, 2-propynyl 2- (diethylphosphoryl) -2-fluoroacetate, methyl 2- (dimethoxyphosphoryl) -2. -Fluoroacetate, methyl 2- (dimethoxyphosphoryl) -2-fluoropropanoate, methyl 2- (diethoxyphosphoryl) -2-fluoroacetate, ethyl 2- (dimethoxyphosphoryl) -2-fluoroacetate, ethyl 2- ( Diethoxyphosphoryl) -2-fluoroacetate, isopropyl 2- (diethoxyphosphoryl) -2-fluoroacetate, vinyl 2- (diethoxyphosphoryl) -2-fluoroacetate, allyl 2- (diethoxyphosphoryl) -2-fluoro Acetate, 2- The nonaqueous electrolytic solution according to claim 2, which is one or more selected from propynyl 2- (diethoxyphosphoryl) -2-fluoroacetate and ethyl 2- (diethoxyphosphoryl) -2-fluoropropanoate. .   The compound represented by the general formula (III) is ethyl 2- (diethylphosphoryl) acetate (structural formula C4), 2-propynyl 2- (diethylphosphoryl) acetate, methyl 2- (dimethoxyphosphoryl) acetate, methyl 2- (Diethoxyphosphoryl) acetate, ethyl 2- (dimethoxyphosphoryl) acetate, ethyl 2- (diethoxyphosphoryl) acetate, ethyl 2- (diethoxyphosphoryl) propanoate, propyl 2- (diethoxyphosphoryl) acetate, isopropyl 2- ( Diethoxyphosphoryl) acetate, vinyl 2- (diethoxyphosphoryl) acetate, allyl 2- (diethoxyphosphoryl) acetate, 2-propynyl 2- (diethoxyphosphoryl) acetate In a non-aqueous electrolyte according to claim 2.   The nonaqueous electrolytic solution according to claim 1, wherein the content of the dihalophosphate compound represented by the general formula (I) is 0.001 to 10% by mass in the nonaqueous electrolytic solution.   The nonaqueous electrolytic solution according to any one of claims 1 to 6, wherein the nonaqueous solvent contains at least one cyclic carbonate.   The cyclic carbonate is ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 4-fluoro-1,3-dioxolan-2-one, trans or cis-4,5-difluoro-1, The nonaqueous electrolytic solution according to claim 7, which is one or more selected from 3-dioxolan-2-one, vinylene carbonate, vinylethylene carbonate, and 4-ethynyl-1,3-dioxolan-2-one. .   The nonaqueous electrolytic solution according to any one of claims 1 to 8, wherein the nonaqueous solvent further contains a chain ester.   Symmetrical chain ester selected from asymmetric chain carbonate selected from methyl ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, and ethyl propyl carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate The nonaqueous electrolytic solution according to claim 9, which is one or more selected from a chain carbonate and a chain carboxylic acid ester. The electrolyte salt is LiPF ₆ , LiPO ₂ F ₂ , Li ₂ PO ₃ F, LiBF ₄ , LiSO ₃ F, LiN (SO ₂ F) ₂ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , one or two selected from lithium bis [oxalate-O, O ′] lithium borate, difluorobis [oxalate-O, O ′] lithium phosphate, and tetrafluoro [oxalate-O, O ′] lithium phosphate The non-aqueous electrolyte in any one of Claims 1-10 containing the lithium salt of a seed | species or more. The lithium salt contains LiPF ₆ , and LiPO ₂ F ₂ , LiBF ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ F) ₂ , lithium bis [oxalate-O, O ′] lithium borate and difluorobis The nonaqueous electrolytic solution according to claim 11, comprising one or more selected from [oxalate-O, O ′] lithium phosphate.   The nonaqueous electrolytic solution according to claim 11 or 12, wherein the concentration of the lithium salt is 0.3 to 2.5 M with respect to the nonaqueous solvent.   An additive for a nonaqueous electrolyte solution for an electricity storage device, comprising the dihalophosphate compound represented by the general formula (I) according to claim 1.   An electricity storage device comprising the positive electrode, the negative electrode, and the nonaqueous electrolytic solution according to claim 1.   The active material of the positive electrode contains a composite metal oxide with lithium containing one or more selected from cobalt, manganese, and nickel, or one or more selected from iron, cobalt, nickel, and manganese The electricity storage device according to claim 15, which is a lithium-containing olivine-type phosphate.   The negative electrode active material contains one or more selected from lithium metal, lithium alloy, carbon material capable of inserting and extracting lithium, tin, tin compounds, silicon, silicon compounds, and lithium titanate compounds The electricity storage device according to claim 15 or 16. A dihalophosphate compound represented by the following general formula (IV).

Wherein R ¹³ and R ¹⁴ are each independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryloxy having 6 to 12 carbon atoms. Represents a group, X ⁴ represents a fluorine atom or a chlorine atom, and p represents 1 or 2.
R ¹⁵ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms when p is 1. When p is 2, an alkylene group having 2 to 6 carbon atoms, an alkenylene group having 4 to 8 carbon atoms, or an alkynylene group having 4 to 8 carbon atoms is shown.
At least one hydrogen atom of the group represented by R ¹³ or R ¹⁴ may be substituted with a halogen atom. When R ¹³ and R ¹⁴ are an alkyl group or an alkoxy group, R ¹³ and R ¹⁴ may be bonded to form a ring structure. However, R ¹³ and R ¹⁴ are both an alkoxy group having 1 to 6 carbon atoms, and R ¹⁵ is an alkyl group having 1 to 2 carbon atoms. )