[Designation of Document] Specification
[Title of the Invention] ESTER COMPOUND, AND NONAQUEOUS ELECTROLYTE SOLUTION AND LITHIUM SECONDARY BATTERY EACH USING THE ESTER COMPOUND [Technical Field] [0001]
The present invention relates to an ester compound useful as intermediate materials for medicines, agricultural chemicals, electronic materials, polymer materials and the like, or as battery materials, as well as to a nonaqueous electrolytic solution comprising it, which is excellent in initial battery capacity and cycle property and capable of maintaining battery performance for a long period of time, and also to a lithium secondary battery using it. [Background Art] [0002]
In recent years, lithium secondary batteries have been widely used as driving power supplies for small electronic devices such as mobile telephones, notebook-size personal computers and the like. A lithium secondary batteries are mainly constituted of a positive electrode and a negative electrode containing a material capable of absorbing and releasing lithium, and a nonaqueous electrolytic solution containing a lithium salt, in which a carbonate such as ethylene carbonate (EC), propylene carbonate (PC) and the like are used as the nonaqueous electrolytic solution.
As the negative electrode for the lithium secondary battery, known are metal lithium, and metal compounds (simple metal substances, oxides, alloys with lithium, etc.) and carbon

materials capable of absorbing and releasing lithium; and in particular, lithium secondary batteries comprising a carbon material such as coke, artificial graphite, natural graphite and the like capable of absorbing and releasing lithium have been widely put into practical use. [0003]
For example, it is known that, in a lithium secondary battery using a highly-crystallized carbon material such as natural graphite, artificial graphite or the like as the negative electrode material therein, the solvent in the nonaqueous electrolytic solution decomposes through reduction on the surface of the negative electrode in charging, and even EC widely used as a solvent for nonaqueous electrolytic solution may partly decompose through reduction during repeated charging and discharging, therefore causing deterioration of battery performance such as battery capacity and cycle property.
Further, it is known that a lithium secondary battery using, as the negative electrode material therein, lithium metal or its alloy, or a simple metal substance such as tin, silicon or the like or its oxide, may have a high initial capacity, in which, however, the negative electrode material may be powdered during cycles and, as compared with a negative electrode of a carbon material, it may accelerate the reductive decomposition of the solvent of the electrolytic solution, therefore greatly deteriorating battery performance such as battery capacity and cycle property.
On the other hand, in a lithium secondary battery comprising, for example, LiCo02, LiMn204, LiNi02 or the like as the positive electrode therein, when the solvent in the nonaqueous electrolytic

solution has a high temperature in a charged state, then it partly decomposes through oxidation locally in the interface between the positive electrode material and the nonaqueous electrolytic solution, and the decomposed product interferes with the desired electrochemical reaction in the battery, therefore deteriorating battery performance.
As in the above, the decomposition of an electrolytic solution on a positive electrode and a negative electrode brings about gas generation therearound to swell the battery, or brings about gas retention between a positive electrode and a negative electrode to interfere with lithium ion movement, therefore being a cause of deteriorating battery performance. Despite of the situation, electronic appliances equipped with lithium secondary batteries therein are in a stream of further increase in the power consumption and, with that, the capacity of lithium secondary batteries is being much increased, therefore bringing about problems in that the electrolytic solution is being much more easily decomposable and the battery characteristics such as cycle property are more worsened. [0004]
Patent Documents 1 and 2 disclose a nonaqueous electrolytic battery in which the nonaqueous electrolytic solution comprises, as dissolved therein, a methoxybenzene-based compound partly substituted with a fluorine atom or the like, proposing a method of evading thermal runaway by redox reaction in an overcharged state. However, these do not refer at all to cycle property, and are therefore not on a satisfactory level.
Patent Document 3 and Patent Document 4 disclose a nonaqueous electrolytic solution with methyl benzoate or vinyl benzoate

dissolved therein, proposing a battery effective for the affinity to a carbon material and for the initial charge-discharge efficiency. However, these do not refer at all to cycle property, and are therefore not on a satisfactory level.
Patent Document 5 discloses a method for producing, as a
production material for antimicrobial agents, methyl
3-methoxy-2,4,5-trifluorobenzoate from
3-methoxy-2,4,5-trifluorobenzoic acid, using dimethyl sulfate.
Patent Document 6 discloses a lithium secondary battery comprising a nonaqueous electrolytic solution of, as dissolved therein, methyl benzoate partly substituted with a fluorine atom or the like, indicating that the lithium secondary battery has a higher discharging capacity than a lithium secondary battery comprising a nonaqueous electrolytic solution of, as dissolved therein, methyl benzoate not substituted with a fluorine atom or the like. However, even the battery is not still on a satisfactory level in point of the initial battery capacity and the cycle property thereof. [0005]
[Patent Document 1] JP-A 10-308236 [Patent Document 2] JP-A 2000-156243 [Patent Document 3] JP-A 8-293323 [Patent Document 4] JP-A 2000-299127 [Patent Document 5] JP-A 3-127755 [Patent Document 6] JP-A 2000-323169 [Disclosure of the Invention] [Problems that the Invention is to Solve] [0006]
An object of the present invention is to provide an ester

compound useful as intermediate materials for various materials, or as battery materials, as well as a nonaqueous electrolytic solution for lithium secondary battery using it, which is excellent in initial battery capacity and cycle property and capable of maintaining good battery performance for a long period of time, and also to a lithium secondary battery using it. [Means for Solving the Problems] [0007]
The present inventors have assiduously studied for the purpose of solving the above-mentioned problems and, as a result, have found that, for a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, when an ester compound having an alkoxy group and a fluorine atom on a benzene ring such as propargyl 3-methoxy-2,4,5-trifluorobenzoate or the like is produced and added to the nonaqueous electrolytic solution, then a lithium secondary battery excellent in the initial battery capacity and the cycle property thereof and capable of maintaining the battery performance for a long period of time can be obtained, and have completed the present invention.
In addition, the present inventors have further found that, for a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, when propargyl 2 ,4-trif luorobenzoate or the like having a fluorine atom on the benzene ring and having an unsaturated bonding site is added to the nonaqueous electrolytic solution, then a lithium secondary battery excellent in the initial battery capacity and the cycle property thereof can be obtained, and have completed the present invention. [0008]

to 10 % by weight of the nonaqueous electrolytic solution: [0011]

(wherein R'11, R11, R1'* and R-*-1 each independently represent a hydrogen atom or a fluorine atom; R11 represents a hydrogen atom, a fluorine atom, a methoxy group or an ethoxy group; at least one of R''''1 to R11 is a fluorine atom; 1? represents an alkyl group having from
1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon
atoms, an alkynyl group having from 3 to 6 carbon atoms, a phenyl
group or a biphenyl group; provided that when all of R11 to R11 are
fluorine atoms, then L1 represents an alkenyl group having from
2 to 6 carbon atoms, an alkynyl group having from 3 to 6 carbon
atoms, a phenyl group or a biphenyl group).
(3) A nonaqueous electrolytic solution comprising an electrolyte salt dissolved in a nonaqueous solvent and containing an ester compound represented by the following general formula (II) and/or (IV) in an amount of from 0.01 to 10 % by weight of the nonaqueous electrolytic solution: [0012]



(wherein R"* represents a methoxy group or an ethoxy group; R1 represents a linear or branched alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 6 carbon atoms, a linear or branched alkynyl group having from 3 to 6 carbon atoms, a phenyl group or a biphenyl group).
(4) A lithium secondary battery comprising a positive electrode, a negative electrode and a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains at least one ester compound selected from those of general formulae (II) , (III) and (IV) in an amount of from 0.01 to 10 % by weight of the nonaqueous electrolytic solution. [Effect of the Invention] [0014]
The lithium secondary battery comprising the nonaqueous electrolyte of the present invention is excellent in the initial battery capacity and the cycle property thereof and can maintain the battery performance for a long period of time. [Best Mode for Carrying out the Invention] [0015]
The ester compound, the nonaqueous electrolytic solution for lithium secondary battery using it, and the lithium secondary battery using it of the present invention are described in detail

hereinunder.
The ester compound of the present invention is represented by the following general formulas (I) or (II):
[Ester compound represented by general formula (I)]
[0016]
[Formula 6]

(wherein R""" represents a methoxy group or an ethoxy group; R1 represents a linear or branched alkenyl group having from 2 to 6 carbon atoms, a linear or branched alkynyl group having from 3 to 6 carbon atoms, a phenyl group or a biphenyl group). [0017]
R1 in the general formula (I) is a methoxy group or an ethoxy group, preferably a methoxy group.
The linear or branched alkenyl group having from 2 to 6 carbon atoms for R1 includes a vinyl group, a 2-propenyl group, a 2-butenyl group, a 3-butenyl group, a 4-pentenyl group, a 2-methyl-2-propenyl group, a 2-methyl-2-butenyl group, a 3-methyl-2-butenyl group, etc. The linear or branched alkynyl group having from 3 to 6 carbon atoms for R1 includes a 2-propynyl group, a 2-butynyl group, a 3-butynyl group, a 4-pentynyl group, a 5-hexynyl group, a 1-methyl-2-propynyl group, a 1-methyl-2-butynyl group, a 1,1-dimethyl-2-propynyl group, etc.
The phenyl group for R1 may be substituted with an alkyl group having from 1 to 6 carbon atoms or a fluorine atom, including a phenyl group, a tolyl group, a xylyl group, a mesityl group, a

fluorophenyl group, etc. The biphenyl group for R1 may be substituted with an alkyl group having from 1 to 6 carbon atoms or a fluorine atom. [0018]
The ester compound represented by the general formula (I)
includes, concretely, vinyl 3-methoxy-2,4,5-trifluorobenzoate
[R1 = methoxy group, R1 = vinyl group], 2-propenyl
3-methoxy-2 ,4, 5-trif luorobenzoate [R'"' = methoxy group, R1 =
2-propenyl group], 2-butenyl 3-methoxy-2,4,5-trifluorobenzoate
[R1 = methoxy group, R1 = 2-butenyl group], 3-butenyl
3-methoxy-2,4, 5-trif luorobenzoate [R'1 = methoxy group, R1 =
3-butenyl group], 4-pentenyl 3-methoxy-2,4,5-trifluorobenzoate
[R1 = methoxy group, R1 = 4-pentenyl group], 2-methyl-2-propenyl
3-methoxy-2,4,5-trifluorobenzoate [R1 = methoxy group, R1 =
2-methyl-2-propenyl group], 3-methyl-2-butenyl
3-methoxy-2,4,5-trifluorobenzoate [R1 = methoxy group, R1 =
3-methyl-2-butenyl group], 2-propynyl
3-methoxy-2,4,5-trifluorobenzoate [R1 = methoxy group, R1 =
2-propynyl group], 2-butynyl 3-methoxy-2,4,5-trifluorobenzoate
[R1 = methoxy group, R1 = 2-butynyl group], 4-pentynyl
3-methoxy-2,4,5-trif luorobenzoate [R"1 = methoxy group, R1 =
4-pentynyl group], 5-hexynyl 3-methoxy-2,4,5-trifluorobenzoate
[R1 = methoxy group, R1 = 5-hexynyl group], 1-methyl-2-propynyl
3-methoxy-2,4,5-trif luorobenzoate [R'1 = methoxy group, R1 =
1-methyl-2-propynyl group], 1,1-dimethyl-2-propynyl
3-methoxy-2,4,5-trifluorobenzoate [R1 = methoxy group, R1 =
1,1-dimethyl-2-propynyl group], phenyl
3-methoxy-2, 4, 5-trif luorobenzoate [R1 = methoxy group, R1 = phenyl group], tolyl 3-methoxy-2,4,5-trifluorobenzoate [R1 = methoxy

methyl
ethyl
vinyl
2-propenyl
2-propynyl
phenyl
tolyl
biphenyl
group, R1 = tolyl group] , xylyl 3-methoxy-2,4,5-trifluorobenzoate [R* = methoxy group, R1 = xylyl group], biphenyl 3-methoxy-2,4,5-trifluorobenzoate [R1 = methoxy group, R1 = biphenyl group], vinyl 3-ethoxy-2,4,5-trifluorobenzoate [R1 = ethoxy group, R1 = vinyl group], 2-propenyl 3-ethoxy-2, 4, 5-trif luorobenzoate [R1 = ethoxy group, R1 = propenyl group] , 2-propynyl 3-ethoxy-2, 4, 5-trif luorobenzoate [R''' = ethoxy group, R1 = 2-propynyl group], phenyl 3-ethoxy-2,4,5-trifluorobenzoate [R1 = ethoxy group, R1 - phenyl group], tolyl 3-ethoxy-2,4,5-trifluorobenzoate [R1 = ethoxy group, R1 = tolyl group], biphenyl 3-ethoxy-2,4,5-trifluorobenzoate [R1 = ethoxy group, R1 = biphenyl group], etc. [0019]
Of those, preferred are 3-methoxy-2,4,5-trifluorobenzoate, 3-methoxy-2,4,5-trifluorobenzoate, 3-methoxy-2,4,5-trifluorobenzoate, 3-methoxy-2,4,5-tri fluorobenzoate, 3-methoxy-2,4,5-trifluorobenzoate, 3-methoxy-2,4,5-trifluorobenzoate, 3-methoxy-2,4,5-trifluorobenzoate, and 3-methoxy-2,4,5-trifluorobenzoate. [0020]
[Ester compound represented by general formula (II)] [0021] [Formula 7]


(wherein R'1 represents a methoxy group or an ethoxy group; L""" represents a linear or branched alkylene group having from 2 to 6 carbon atoms, a linear or branched alkenylene group having from 4 to 6 carbon atoms, or a linear or branched alkynylene group having from 4 to 6 carbon atoms). [0022]
R1 in the general formula (II) is a methoxy group or an ethoxy group, preferably a methoxy group.
The linear or branched alkylene (alkanediyl) group having from 2 to 6 carbon atoms for L1 includes an ethylene group, a 1, 2-propylene group, a 1, 3-propylene group, a 1,2-butylene group, a 1,3-butylene group, a 1,4-butylene group, a 2,3-butylene group, a 1,3-pentylene group, a 1,4-pentylene group, a 1,5-pentylene group, a 2 , 4-pentylene group, a 1, 5-hexylene group, a 1, 6-hexylene group, a 2,4-hexylene group, etc. Of those, preferred is a branched alkylene group such as a 1,2-propylene group, a 1,3-butylene group, a 2,3-butylene group, a 1,4-pentylene group, a 2,4-pentylene group, a 2,4-hexylene group, etc.; and more preferred is an alkylene group branched with a methyl group, such as 1,2-propylene group (propan-l-2-diyl group), a 1,3-butylene group, a 2,3-butylene group, etc.
The linear or branched alkenylene group having from 4 to 6 carbon atoms for L1 includes a 2-butenylene group, a 2-pentenylene group, 2-hexenylene, a 3-hexenylene group, a 1,4-dimethyl-2-butenylene group, etc.

The linear or branched alkynylene group having from 4 to 6 carbon atoms for L" includes a 2-butynylene group, a 2-pentynylene group, 2-hexynylene, a 3-hexynylene group, a 1,4-dimethyl-2-butynylene group, etc.
The phenyl group and the biphenyl group for L'"' may be substituted with an alkyl group having from 1 to 6 carbon atoms or a fluorine atom. [0023]
The ester compound represented by the general formula (II)
includes, concretely, ethylene glycol
bis (3-raethoxy-2, 4, 5-trifluorobenzoate) [R1 = methoxy group, L1 =
ethylene group], 1,2-propanediol
bis (3-methoxy-2 , 4 , 5-trifluorobenzoate) [R1 = met hoxy group, L1 =
1,2-propylene group], 1,3-propanediol
bis (3-methoxy-2, 4 , 5-trifluorobenzoate) [R1 = methoxy group, L1 =
1,3-propylene group], 1,3-butanediol
bis (3-methoxy-2, 4 , 5-trifluorobenzoate) [R1 = methoxy group, L1 =
1,3-butylene group], 1,4-butanediol
bis (3-methoxy-2, 4, 5-trifluorobenzoate) [R1 = methoxy group, L"1 =
1,4-butylene group], 2,3-butanediol
bis (3-methoxy-2, 4, 5-trifluorobenzoate) [R1 = methoxy group, L-1 =
2,3-butylene group], 1,3-dimethyl-l,3-propanediol
bis (3-methoxy-2, 4, 5-trifluorobenzoate) [R1 = methoxy group, L1 =
2,4-pentylene group], 1,4-dimethyl-1,4-butanediol
bis (3-methoxy-2 , 4 , 5-trifluorobenzoate) [R'1 = methoxy group, L""" =
2,5-hexylene group], 2-butene-l,4-diol
bis (3-methoxy-2 , 4 , 5-trifluorobenzoate) [R'1 = methoxy group, L1 =
2-butenylene group], 2-butyne-1,4-diol
bis (3-methoxy-2 , 4, 5-trifluorobenzoate) [R1 = methoxy group, L'"' =

2-butynylene group], etc. [0024]
Of those, preferred are ethylene glycol
bis(3-methoxy-2,4,5-trifluorobenzoate), 1,2-propanediol
bis(3-methoxy-2,4,5-trifluorobenzoate), 1,3-propanediol
bis(3-methoxy-2,4,5-trifluorobenzoate), 1,2-butanediol
bis(3-methoxy-2,4,5-trifluorobenzoate), 1,3-butanediol
bis(3-methoxy-2,4,5-trifluorobenzoate), 1,4-butanediol
bis{3-methoxy-2,4,5-trifluorobenzoate), 2,3-butanediol bis(3-methoxy-2,4,5-trifluorobenzoate), 2-butyne-l,4-diol bis(3-methoxy-2,4,5-trifluorobenzoate); and more preferred are compounds having an alkylene group branched with a methyl group such as 1, 2-propanediol bis (3-methoxy-2 , 4 , 5-trif luorobenzoate) , 1,3-butanediol bis(3-methoxy-2 , 4,5-trifluorobenzoate), 2,3-butanediol bis(3-methoxy-2,4,5-trifluorobenzoate), etc. [0025]
[Production method for ester compound represented by general formula (I)]
The ester compound represented by the general formula (I) of the present invention can be produced according to (a) a transesterification method and (b) an acid chloride method mentioned below; however, the present invention is not limited to these production methods, (a) Transesterification method:
The transesterification method is a method for producing the intended ester compound through transesterification of 3-methoxy-2,4,5-trifluorobenzoic acid (hereinafter referred to as "MTFBA") in a solvent or not in a solvent, in the presence of a base and a metal catalyst.

The ester compound to be transesterif led with MTFBA includes a fatty acid ester, for example, an acetate such as vinyl acetate, as well as a propionate, a butyrate, a valerate, etc. Of those, more preferred is an acetate. The amount of the ester to be used is preferably from 1 to 50 mols, more preferably from 4 to 20 mols, relative to 1 mol of MTFBA. [0026]
The metal catalyst to be used in the transesterification includes a divalent palladium compound, a divalent iridium compound, etc. Concretely, preferred are Pd(0Ac)2/ Pd(0C0Et)2/ PdCl2, Li2PdCl4, [Ir(cod)Cl] 2, and mixtures of those compounds, etc.
The amount of the metal catalyst to be used is preferably from 0.001 to 20 % by weight of the overall weight of the reaction liquid, more preferably from 0.01 to 10 % by weight, even more preferably from 0.1 to 5 % by weight.
The base catalyst includes an alkali metal or alkaline earth metal hydroxide, carbonate, phosphate, acetate and their mixtures, etc. Concretely, preferred are potassium hydroxide, potassium carbonate, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, sodium acetate, lithium hydroxide . The amount of the base catalyst to be used is preferably from 0.01 to 20 % by weight of the overall weight of the reaction liquid, more preferably from 0.05 to 10 % by weight, even more preferably from 0.1 to 5 % by weight. [0027]
In the transesterification, usable is a solvent inert under the reaction condition. The usable inert solvent includes aliphatic hydrocarbons such as hexane, heptane, etc.;

halogenohydrocarbons such as dichloroethane, dichloropropane, etc.; aromatic hydrocarbons such as toluene, xylene, etc.; halogenoaromatic hydrocarbons such as chlorobenzene, fluorobenzene, etc.; ethers such as diethyl ether, etc.; nitriles such as acetonitrile, propionitrile, etc.; amides such as N,N-dimethylformamide, etc.; sulfoxides such as dimethyl sulfoxide, etc.; nitro compounds such as nitromethane, nitroethane, etc.; or their mixtures. Especially preferred are toluene, xylene, N,N-dimethylformamide. The amount of the inert solvent to be used is preferably from 0.01 to 20 parts by weight, more preferably from 1 to 5 parts by weight, relative to 1 part by weight of MTFBA. [0028]
The temperature in the transesterification is preferably
not lower than -2 0°C, more preferably not lower than 0°C so as not to lower the reactivity. The uppermost limit of the reaction
temperature is preferably 80°C or lower, more preferably 60°C or lower. When the reaction temperature exceeds 80°C, then side reaction or decomposition of products may occur.
The reaction time varies depending on the reaction temperature and the scale, but is preferably from 0.5 to 3 0 hours, more preferably from 1 to 48 hours. When the reaction time is too short, then the unreacted matter may remain; but on the contrary, when the reaction time is too long, then the product may be decomposed or side reaction may occur. [0029] (b) Acid chloride method:
The acid chloride method is a method for producing the intended ester compound through esterif ication of an acid chloride

of MTFBA with an alcohol in a solvent or not in a solvent in the presence of a base.
The amount of the alcohol to be reacted with an acid chloride of MTFBA is preferably from 1 to 2 0 mols relative to 1 mol of MTFBA, more preferably from 1 to 5 mols. The acid chloride of MTFBA can be prepared through reaction of MTFBA with thionyl chloride.
In producing the ester compound from the acid chloride, hydrogen chloride gas is produced as a by product. Not collected, the hydrogen chloride gas may be removed away from the reaction system and absorbed by a neutralization tank; or a base is made to exist in the reaction system, and the gas may be caught through neutralization in the reaction system. For removing the hydrogen chloride gas away from the reaction system, there may be employed a method of bubbling the reaction liquid with an inert gas; or a method of exposing the reaction liquid to a reduced pressure. In any case, the range of the operation temperature is preferably from 0 to 100°C. [0030]
In case where the ester is produced from an acid chloride of MTFBA not using a base, a solvent may be used or may not be used. In case where the ester is produced using a base, it is desirable to additionally use a solvent inert under the reaction condition, as a neutralized salt exists in the reaction system. The inert solvent usable in common in any case includes aliphatic hydrocarbons such as hexane, heptane, etc. ; halogenohydrocarbons such as dichloroethane, dichloropropane, etc.; aromatic hydrocarbons such as toluene, xylene, etc.; halogenoaromatic hydrocarbons such as chlorobenzene, fluorobenzene, etc.; ethers such as diethyl ether, etc.; nitriles such as acetonitrile.

propionitrile, etc.; amides such as N,N-dimethylformamide, etc . ; sulfoxides such as dimethyl sulfoxide, etc. ; nitro compounds such as nitromethane, nitroethane, etc.; or their mixtures. Especially preferred are toluene, xylene, N, N-dimethylf ormamide. The amount of the inert solvent to be used is preferably from 0 to 10 parts by weight, more preferably from 1 to 2 parts by weight, relative to 1 part by weight of MTFBA. [0031]
As the base, usable are any of an inorganic base and an organic base. These may be used singly or as combined. The inorganic base usable herein includes potassium carbonate, sodium carbonate, calcium hydroxide, calcium oxide, etc. The organic base usable herein includes linear-chain or branched-chain aliphatic tertiary amines, and mono-substituted or poly-substituted pyrrole, pyrrolidone, imidazole, imidazolidinone, pyridine, pyrimidine, quinoline, N,N-dialkylcarboxyamide, etc.
Of those, especially preferred are trialkylamines such as
trimethylamine, triethylamine, tripropylamine, tributylamine,
ethyldiisopropylamine, etc.; and pyridine, N-methylpyrrolidone,
N,N-dimethylacetamide, N,N-dimethylaminopyridine,
1, 3-dimethylimidazolidinone. The amount of the base to be used is preferably from 0.8 to 5 mols relative to 1 mol of MTFBA, more preferably from 1 to 3 mols, even more preferably from 1 to 1.5 mols, as capable of preventing production of side products. [0032]
In the reaction of an acid chloride of MTFBA with an alcohol, the lowermost limit of the reaction temperature is preferably -20°C or higher, more preferably 0°C or higher so as not to lower the

reactivity. The uppermost limit of the reaction temperature is preferably 80or lower, more preferably 60°C or lower. When the reaction temperature exceeds 80°C, then side reaction or decomposition of products may occur.
The reaction time varies depending on the reaction temperature and the scale, but is preferably from 0.1 to 12 hours, more preferably from 0.2 to 6 hours. When the reaction time is too short, then the unreacted matter may remain; but on the contrary, when the reaction time is too long, then the product may be decomposed or side reaction may occur. [0033]
[Production method for ester compound represented by general formula (II)]
The ester compound represented by the general formula (II) of the present invention can be produced according to the above-mentioned acid chloride method (b) . Specifically, the compound may be produced through esterif ication of an acid chloride of MTFBA with a diol in a solvent or not in a solvent in the presence of a base; however, the production method is not limitative.
The amount of the diol to be reacted with an acid chloride of MTFBA is preferably from 1 to 2 0 mols, more preferably from 1 to 5 mols, relative to 1 mol of MTFBA.
The type and the amount of the inert solvent and the base to be used are the same as those mentioned in the above; and the reaction temperature and the reaction time are also the same as above. [0034] [Compound represented by general formula (III)]
The compound to be in the nonaqueous electrolytic solution

in the present invention is represented by the following general
formula (III):
[0035]

(wherein R11, R11, R"1* andR-11 each independently represent a hydrogen atom or a fluorine atom,- R11 represents a hydrogen atom, a fluorine atom, a methoxy group or an ethoxy group,- at least one of R11 to R11 is a fluorine atom,- L1 represents an alkyl group having from
1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon
atoms, an alkynyl group having from 3 to 6 carbon atoms, a phenyl
group or a biphenyl group,- provided that when all of R'''1 to R11 are
fluorine atoms, then L1 represents an alkenyl group having from
2 to 6 carbon atoms, an alkynyl group having from 3 to 6 carbon
atoms, a phenyl group or a biphenyl group).
[0037]
The alkenyl group having from 2 to 6 carbon atoms for 1? includes a linear alkenyl group such as an ethenyl group (vinyl group), a 2-propenyl group (allyl group), a 2-butenyl group, a 3-butenyl group, a 4-pentenyl group, etc. ,- and a branched alkenyl group such as a 2-methyl-2-propenyl group, a 3-methyl-2-butenyl group, etc.
The alkynyl group having from 3 to 6 carbon atoms for L1 includes a linear alkynyl group such as 2-propynyl group (propargyl group), a 2-butynyl group, a 3-butynyl group, a 4-pentynyl group.

a 5-hexynyl group, etc.; and a branched alkynyl group such as a 1-methyl-2-propynyl group, a 1-methyl-2-butynyl group, a 1,1-dimethyl-2-propynyl group, etc.
The phenyl group for 1? may be substituted with an alkyl group having from 1 to 6 carbon atoms or a fluorine atom, including a phenyl group, a tolyl group, a xylyl group, a mesityl group, a fluorophenyl group, etc. The biphenyl group may be substituted with an alkyl group having from 1 to 6 carbon atoms or a fluorine atom. [0038]
Of the ester compounds represented by the general formula
(III), linear alkenyl esters include, concretely, vinyl
2-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen
atom, l/ - vinyl group] , vinyl 3-fluorobenzoate [R11 = fluorine atom,
R11 = R11 = R1* = R11 = hydrogen atom, L1 = vinyl group] , vinyl
4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1'* = R11 = hydrogen
atom, ll = vinyl group] , vinyl 2,4-dif luorobenzoate [R11 = R11 =
fluorine atom, R11 = R11 = R"11 = hydrogen atom, L1 = vinyl group] ,
vinyl 2,6-difluorobenzoate [R11 = R11 = fluorine atom, R11 = R11 =
R""11 = hydrogen atom, L1 = vinyl group] , vinyl
2,4, 6-trifluorobenzoate [R11 = R11 = R11 = fluorine atom, R11 = R1"*
hydrogen atom, l} = vinyl group], vinyl
2, 3,4, 6-tetrafluorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R'"''* = hydrogen atom, \? = vinyl group] , vinyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R11 = R" = R" = R" = R11 = fluorine atom, L1 = vinyl group] , 2-propenyl 2-fluorobenzoate [R"''1 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, 1? = 2-propenyl group] , 2-propenyl 3-f luorobenzoate [R11 = fluorine atom, R11 = R1"' = R11 = R11 = hydrogen atom, L1 = 2-propenyl group], 2-propenyl

4-fluorobenzoate [R1' = fluorine atom, R1'1 = R11 = R1* = R11 = hydrogen atom, L1 = 2-pi"openyl group] , 2-propenyl 2, 4-dif luorobenzoate [R'''1 = R11 = fluorine atom, R-11 = R-11 = R-11 = hydrogen atom, L1 = 2-propenyl group] , 2-propenyl 2, 6-dif luorobenzoate [R11 = R11 = fluorine atom, ■R11 - R11 = R"11 = hydrogen atom, L1 = 2-propenyl group]-, 2-propenyl 2, 4, 6-trif luorobenzoate [R11 = R11 = R11 = fluorine atom, R11 = R1"* = hydrogen atom, L1 = 2-propenyl group], 2-propenyl 2, 3,4, 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R-'1'1 = hydrogen atom, L1 = 2-propenyl group] , 2-propenyl 2, 3,4, 5, 6-pentafluorobenzoate [R11 = R11 = R11 = R11 = R11 = fluorine atom, 1? ~ 2-propenyl group], 2-butenyl 2-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, L1 = 2-butenyl group] , 2-butenyl 3-fluorobenzoate [R''11 = fluorine atom, R11 = R11 = R"11 = R-11 = hydrogen atom, L1 = 2-butenyl group] , 2-butenyl 4-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, L1 = 2-butenyl group] , 2-butenyl 2,4-dif luorobenzoate [R''-1 = R11 = fluorine atom, R11 = R1* = R11 = hydrogen atom, L1 = 2-butenyl group] , 2-butenyl 2, 6-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R1"* = hydrogen atom, 1? = 2-butenyl group] , 2-butenyl 2, 4, 6-trif luorobenzoate [R11 = R11 = R11 = fluorine atom, R11 = R1"* hydrogen atom, L1 = 2-butenyl group], 2-butenyl 2, 3,4, 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R1"* = hydrogen atom, L1 = 2-butenyl group] , 2-butenyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R11 - R11 = R" = R" = R11 = fluorine atom, ll = 2-butenyl group] , 3-butenyl 2-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R1'* = R11 = hydrogen atom, L1 = 3-butenyl group] , 3-butenyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 3-butenyl group] , 3-butenyl 4-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R1"* = R11 = hydrogen

atom, L1 = 3-butenyl group], 3-butenyl 2,4-difluorobenzoate [R11 - R-' = fluorine atom, R11 = R'1 = R"11 = hydrogen atom, L1 = 3-butenyl group] , 3-butenyl 2, 6-dif luorobenzoate [R"1"1 = R11 = fluorine atom, j1i2 1 j1i3 1 j1i4 1 hydrogen atom, L1 = 3-butenyl group] , 3-butenyl 2, 4, 6-trifluorobenzoate [R11 -1 R11 = R11 = fluorine atom, R11 = R11 hydrogen atom, L1 = 3-butenyl group], 3-butenyl 2, 3,4, 6-tetrafluorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R-11 = hydrogen atom, l/ = 3-butenyl group] , 3-butenyl 2, 3,4,5, 6-pentafluorobenzoate [R11 = R" = R" = R" = R11 = fluorine atom, L1 = 3-butenyl group], 4-pentenyl 2-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 4-pentenyl group] , 4-pentenyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R'''1 = hydrogen atom, L1 = 4-pentenyl group] , 4-pentenyl 4-fluorobenzoate [R" = fluorine atom, R" = R11 = R1* = R11 = hydrogen atom, L1 = 4-pentenyl group] , 4-pentenyl 2,4-difluorobenzoate [R11 = R11 = fluorine atom, R11 = R-11 = R11 = hydrogen atom, l/ = 4-pentenyl group] , 4-pentenyl 2, 5-difluorobenzoate [R11 = R11 = fluorine atom, j1i2 _ j1i3 _ j1i4 _ hydrogen atom, L1 = 4-pentenyl group] , 4-pentenyl 2, 4, 6-trifluorobenzoate [R11 = R11 = R11 = fluorine atom, R11 = R11 hydrogen atom, L1 = 4-pentenyl group], 4-pentenyl 2, 3,4, 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R11 = hydrogen atom, L1 = 4-pentenyl group], 4-pentenyl 2, 3,4, 5, 6-pentafluorobenzoate [R11 = R11 = R" = R11 = R11 = fluorine atom, L1 = 4-pentenyl group], etc. [0039]
Branched alkenyl esters include 2-methyl-2-propenyl 2-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, L1 = 2-methyl-2-propenyl group], 2-methyl-2-propenyl 3-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen

atom, L1 = 2-methyl-2-propenyl group], 2-methyl-2-propenyl 4-fluorobenzoate [R" = fluorine atom, R" = R11 = R11 = R11 = hydrogen atom, L1 = 2-methyl-2-propenyl group] , 2-methyl-2-propenyl 2,4-difluorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R11 = hydrogen atom, L1 = 2-methyl-2-propenyl group], 2-methyl-2-propenyl 2 , 6-dif luorobenzoate [R"11 = R11 - fluorine atom, j1i2 1 p1i3 1 j1i4 1 hydrogen atom, L1 = 2-methyl-2-propenyl group] , 2-methyl-2-propenyl 2,4, 6-trif luorobenzoate [R1-1 = R11 = R11 = fluorine atom, R"11 = R"11 = hydrogen atom, L1 = 2-methyl-2-propenyl group] , 2-methyl-2-propenyl 2, 3 , 4, 6-tetraf luorobenzoate [R-"-1 = R""-1 R'11 = R11 = fluorine atom, R1"* = hydrogen atom, L1 = 2-methyl-2-propenyl group], 2-methyl-2-propenyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R11 = R11 = R" = R" = R" = fluorine atom, 1? = 2-methyl-2-propenyl group], 3-methyl-2-butenyl 2-fluorobenzoate [R" = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, TJ = 3-methyl-2-butenyl group], 3-methyl-2-butenyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, j/ = 3-methyl-2-butenyl group], 3-methyl-2-butenyl 4-f luorobenzoate [R" = fluorine atom, R11 = R11 = R1"* = R11 = hydrogen atom, l/ = 3-methyl-2-butenyl group], 3-methyl-2-butenyl 2,4-dif luorobenzoate [R" = R" = fluorine atom, R11 - R" = R" = hydrogen atom, l/ = 3-methyl-2-butenyl group] , 3-methyl-2-butenyl 2, 6-difluorobenzoate [R" = R" = fluorine atom, R11 = R" = R" = hydrogen atom, L1 = 3-methyl-2-butenyl group] , 3-methyl-2-butenyl 2,4, 6-trif luorobenzoate [R11 = R11 = R" = fluorine atom, R11 = R11 hydrogen atom, L1 = 3-methyl-2-butenyl group], 3-methyl-2-butenyl 2 , 3 , 4 , 6-tetraf luorobenzoate [R11 = R11 = R" = R11 = fluorine atom, R1* = hydrogen atom, L1 = 3-methyl-2-butenyl group], 3-methyl-2-butenyl 2,3,4,5,6-pentafluorobenzoate [R11 =

R11 = R" = R11 = R-- = fluorine atom, iJ = 3-methyl-2-butenyl group] ,
etc.
[0040]
Linear alkynyl esters include 2-propynyl 2-fluorobenzoate
[R11 - fluorine atom, R11 = R11 = R" = R11 = hydrogen atom, L1 = 2-propynyl group], 2-propynyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, iJ = 2-propynyl group] , 2-propynyl 4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 2-propynyl group], 2-propynyl 2,4-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R11 = hydrogen atom, L1 = 2-propynyl group], 2-propynyl 2, 6-difluorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R1* = hydrogen atom, L1 = 2-propynyl group], 2-propynyl 2, 4, 6-trif luorobenzoate [R" = R" = R11 = fluorine atom, R11 = R11 hydrogen atom, L1 = 2-propynyl group], 2-propynyl 2, 3,4, 6-tetrafluorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R1** = hydrogen atom, l/ = 2-propynyl group] , 2-propynyl 2,3,4,5, 6-pentaf luorobenzoate [R11 = R11 = R" = R11 = R11 = fluorine atom, L1 = 2-propynyl group], 2-butynyl 2-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, j/ = 2-butynyl group] , 2-butynyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R-11 = R"""1 = R11 = hydrogen atom, L1 = 2-butynyl group] , 2-butynyl 4-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 2-butynyl group], 2-butynyl 2,4-difluorobenzoate [R11 = R11 = fluorine atom, R11 == R1* = R11 = hydrogen atom, L1 1 2-butynyl group] , 2-butynyl 2,6-dif luorobenzoate [R11 - R11 = fluorine atom, j1i2 1 j1i3 1 j1i4 1 hydrogen atom, L1 = 2-butynyl group] , 2-butynyl 2, 4, 6-trifluorobenzoate [R11 = R11 = R11 = fluorine atom, R11 = R11 hydrogen atom, L1 = 2-butynyl group], 2-butynyl

2, 3,4, 6-tetraf luorobenzoate [R"1 = R11 = R11 = R*1 = fluorine atom, R1' = hydrogen atom, l/ = 2-butynyl group] , 2-butynyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R11 - R11 = R11 = R1"* = R11 = fluorine atom, L1 = 2-butynyl group], 3-butynyl 2-fluorobenzoate [R11 = fluorine atom, R11 = R" = R1"* = R11 = hydrogen atom, l/ = 3-butynyl.. group] , 3-butynyl 3-fluorobenzoate [R"11 = fluorine atom, R11 = R" = R1"* = R11 = hydrogen atom, L1 = 3-butynyl group] , 3-butynyl 4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 ::1 3-butynyl group] , 3-butynyl 2,4-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R11 = hydrogen atom, l/ = 3-butynyl group] , 3-butynyl 2, 6-dif luorobenzoate [R11 = R"11 = fluorine atom, R12 1 j1i3 1 j1i4 1 hydrogen atom, L1 = 3-butynyl group] , 3-butynyl 2,4, 6-trif luorobenzoate [R11 = R" = R" = fluorine atom, R11 = R11 hydrogen atom, L1 - 3-butynyl group], 3-butynyl 2, 3, 4, 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R11 = hydrogen atom, l/ = 3-butynyl group], 3-butynyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R" = R11 = R" = R" = R" = fluorine atom, L1 = 3-butynyl group], 4-pentynyl 2-f luorobenzoate [R1'1 = fluorine atom, R11 = R11 = R1* 1 R11 = hydrogen atom, L1 = 4-pentynyl group] , 4-pentynyl 3-f luorobenzoate [R11 = fluorine atom, R-11 = R11 = R-"11 = R-11 = hydrogen atom, iJ = 4-pentynyl group] , 4-pentynyl 4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1"* = R11 = hydrogen atom, L1 - 4-pentynyl group] , 4-pentynyl 2, 4-dif luorobenzoate [R11 = R" = fluorine atom, R11 = R1'* = R11 = hydrogen atom, L1 = 4-pentynyl group] , 4-pentynyl 2 , 6-dif luorobenzoate [R11 = R11 = fluorine atom, P1i2 _ j1is _ p1i4 _ hydrogen atom, l/ = 4-pentynyl group] , 4-pentynyl 2,4, 6-trif luorobenzoate [R11 = R" = R" = fluorine atom, R11 = R11 hydrogen atom, L1 = 4-pentynyl group], 4-pentynyl 2, 3,4, 6-tetrafluorobenzoate [R11 = R11 = R11 = R11 = fluorine atom.

R"1 = hydrogen atom, L1 = 4-pentynyl group], 4-pentynyl 2, 3,4, 5, 6-pentafluorobenzoate [R" = R"1 = R"1 = R1'* = R11 = fluorine atom, L1 = 4-pentynyl group] , 5-hexynyl 2-f luorobenzoate [R1''" = fluorine atom, R-11 = R11 = R"11 = R"11 = hydrogen atom, L1 = 5-hexynyl group] , 5-hexynyl 3-fluorobenzoate [R"11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, L1 = 5-hexynyl group] , 5-hexynyl 4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1'* = R11 = hydrogen atom, L1 = 5-hexynyl group] , 5-hexynyl 2, 4-dif luorobenzoate [R''1''" = R-11 = fluorine atom, R11 = R"11 = R11 = hydrogen atom, L1 = 5-hexynyl group] , 5-hexynyl 2, 6-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R11 = hydrogen atom, L1 = 5-hexynyl group] , 5-hexynyl 2,4, 6-trifluorobenzoate [R11 = R11 = R11 = fluorine atom, R11 = R11 hydrogen atom, L1 = 5-hexynyl group], 5-hexynyl 2, 3,4, 6-tetrafluorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R11 = hydrogen atom, I? = 5-hexynyl group] , 5-hexynyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R11 = R11 = R" = R" = R" = fluorine atom, L1 = 5-hexynyl group] , etc. [0041]
Branched-chain alkynyl esters include 1-methyl-2-propynyl 2-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R1"* = R11 = hydrogen atom, jj = 1-methyl-2-propynyl group], 1-methyl-2-propynyl 3-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 1-methyl-2-propynyl group] , 1-methyl-2-propynyl 4-f luorobenzoate [R" = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 1-methyl-2-propynyl group] , 1-methyl-2-propynyl 2,4-dif luorobenzoate [R11 = R" = fluorine atom, R11 = R1"* = R11 = hydrogen atom, L1 = 1-methyl-2-propynyl group], 1-methyl-2-propynyl 2, 6-dif luorobenzoate [R"1"1 = R"11 = fluorine atom, j1i2 1 j1i3 1 j1i4 1 hydrogen atom, l/ = 1-methyl-2-propynyl group] ,

1-methyl-2-propynyl 2 , 4 , 6-trif luorobenzoate [R = R11 = R11 = fluorine atom, R11 = R1* = hydrogen atom, L1 = 1-methyl-2-propynyl group], 1-methyl-2-propynyl 2 , 3, 4, 6-tetrafluorobenzoate [R"1"1 = R11 R11 = R11 = fluorine atom, R11 = hydrogen atom, L1 = 1-methyl-2-propynyl group], 1-methyl-2-propynyl 2,3,4,5,6 -pentafluorobenzoate [R" = R11 = R" = R1* = R" = fluorine atom, L1 = 1-methyl-2-propynyl group], 1-methyl-2-butynyl 2-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, L1 = 1-methyl-2-butynyl group], 1-methyl-2-butynyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R" = R1"* = R11 = hydrogen atom, L1 = 1-methyl-2-butynyl group], l-methyl-2-butynyl 4-fluorobenzoate [R" = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 1-methyl-2-butynyl group], l-methyl-2-butynyl 2,4-dif luorobenzoate [R" = R" = fluorine atom, R11 = R" = R" = hydrogen atom, j/ = 1-methyl-2-butynyl group] , l-methyl-2-butynyl 2, 6-difluorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R1"* = hydrogen atom, L1 = 1-methyl-2-butynyl group] , l-methyl-2-butynyl 2, 4, 6-trif luorobenzoate [R11 = R11 = R" = fluorine atom, R11 = R1* hydrogen atom, l/ = 1-methyl-2-butynyl group], 1-methyl-2-butynyl 2 , 3 , 4 , 6-tetraf luorobenzoate [R11 = R11 = R11 = R-11 = fluorine atom, R-11 = hydrogen atom, L1 = l-methyl-2-butynyl group], 1-methyl-2-butynyl 2,3,4,5,6-pentafluorobenzoate [R11 = R12 1 j1i3 1 jji4 1 j1i5 1 fluorine atom, L1 = l-methyl-2-butynyl] , 1,1-dimethyl-2-propynyl 2-fluorobenzoate [R111 = fluorine atom, R-11 = R11 - R11 = R11 = hydrogen atom, L1 = 1,1-dimethyl-2-propynyl group] , 1,1-dimethyl-2-propynyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 1,1-dimethyl-2-propynyl group] , 1,1-dimethyl-2-propynyl 4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = 1,1-dimethyl-2-propynyl group] ,

1,1-dimethyl-2-propynyl 2 , 4-dif luorobenzoate [R'"'1 = R11 = fluorine atom, R"11 =-- R-1' = R*'' = hydrogen atom, L1 = 1, 1-dimethyl-2-propynyl group] , 1,1-dimethyl-2-propynyl 2 , 6-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R" = R11 = hydrogen atom, l/ = 1,1-dimethyl-2-propynyl group], 1,1-dimethyl-2-propynyl 2,4, 6-trif luorobenzoate [R" = R" = R11 = fluorine atom, R11 = R11 hydrogen atom, L1 = 1,1-dimethyl-2-propynyl group], 1,1-dimethyl-2-propynyl 2 , 3 , 4 , 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R1* = hydrogen atom, L1 = 1,1-dimethyl-2-propynyl group], 1,1-dimethyl-2-propynyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R11 = R11 = R" = R1* = R" = fluorine atom, l/ = 1,1-dimethyl-2-propynyl group], etc. [0042]
Aromatic esters include phenyl 2-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, l/ = phenyl group] , phenyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, L1 = phenyl group] , phenyl 4-fluorobenzoate [R1'1 = fluorine atom, R11 = R11 = R1" = R11 = hydrogen atom, L1 = phenyl group] , phenyl 2, 4-dif luorobenzoate [R"11 = R'11 = fluorine atom, R11 = R-"-* = R11 = hydrogen atom, L1 = phenyl group] , phenyl 2, 6-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R11 = hydrogen atom, l/ = phenyl group] , phenyl 2 , 4, 6-trif luorobenzoate [R11 = R11 = R11 = fluorine atom, R11 = R1"* = hydrogen atom, L1 = phenyl group], phenyl 2 , 3 , 4 , 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R1* = hydrogen atom, l? = phenyl group] , phenyl 2, 3,4,5, 6-pentafluorobenzoate [R11 = R11 = R11 = R" = R" = fluorine atom, L1 = phenyl group] , tolyl 2-f luorobenzoate [R1"'' = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = tolyl group] , tolyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen

atom, L1 = tolyl group] , tolyl 4-f luorobenzoate [R""11 = fluorine atom, R-- = R-1 = R1-- = R"= = hydrogen atom, L1 = tolyl group] , tolyl 2,4-difluorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R11 = hydrogen atom, L1 = tolyl group] , tolyl 2,6-difluorobenzoate [R11 = R11 = fluorine atom, R11 = R-11 = R1'* = hydrogen atom, L1 = tolyl group] , tolyl 2,4, 6-trif luorobenzoate [R11 = R11 = R11 = fluorine atom, R11 R11 = hydrogen atom, l/ = tolyl group] , tolyl 2, 3,4, 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R11 = hydrogen atom, jJ = tolyl group] , tolyl 2, 3, 4, 5, 6-pentaf luorobenzoate [R11 = R11 = R" = R11 = R11 = fluorine atom, l/ - tolyl group] , xylyl 2-f luorobenzoate [R1'1 = fluorine atom, j1i2 1 j1i3 1 j1i4 1 j1i5 _ hydrogen atom, L1 = xylyl group] , xylyl 3-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1* = R11 = hydrogen atom, 1? - xylyl group] , xylyl 4-f luorobenzoate [R11 = fluorine atom, R11 = R12 1 R" = R11 = hydrogen atom, L1 = xylyl group] , xylyl 2,4-difluorobenzoate [R" = R11 = fluorine atom, R11 = R1* = R11 = hydrogen atom, L1 = xylyl group] , xylyl 2, 6-dif luorobenzoate [R1'"' = R11 = fluorine atom, R11 = R11 = R1"* = hydrogen atom, 1? = xylyl group] , xylyl 2,4, 6-trifluorobenzoate [R11 = R11 = R11 = fluorine atom, R11 R1'* = hydrogen atom, L1 = xylyl group] , xylyl 2, 3,4, 6-tetrafluorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R1"* = hydrogen atom, L1 = xylyl group] , xylyl 2, 3,4, 5, 6-pentaf luorobenzoate [R11 = R11 = R" = R" = R11 = fluorine atom, l/ = xylyl group], mesityl 2-fluorobenzoate [R11 = fluorine atom, R"''1 = R11 = R"'''* = R"''1 = hydrogen atom, L1 = mesityl group] , mesityl 3-f luorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = mesityl group] , mesityl 4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R1"1 = R11 = hydrogen atom, L1 = mesityl group] , mesityl 2,4-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R1'* = R11 =

hydrogen atom, L1 = mesityl group] , mesityl 2, 6-difluorobenzoate [R"" = R"1 = fluorine atom, R'1 = R~1 = R1"1 = hydrogen atom, L1 = mesityl group] , mesityl 2 ,4 , 6-trif luorobenzoate [R11 = R11 = R11 = fluorine atom, R"''1 = R"1* = hydrogen atom, L1 = mesityl group] , mesityl 2,-3, 4, 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R" = hydrogen atom, L1 = mesityl group], mesityl 2, 3,4, 5, 6-pentafluorobenzoate [R11 = R11 = R" = R11 = R" = fluorine atom, I? - mesityl group] , fluorophenyl 2-fluorobenzoate [R'''1 = fluorine atom, R11 - R11 = R"11 = R"11 = hydrogen atom, iJ = fluorophenyl group] , fluorophenyl 3-fluorobenzoate [R"11 = fluorine atom, R"''"'' = R11 = R11 = R11 = hydrogen atom, TJ = fluorophenyl group] , fluorophenyl 4-fluorobenzoate [R11 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, j/ = fluorophenyl group] , fluorophenyl 2 , 4-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R11 = R11 = hydrogen atom, L1 = fluorophenyl group] , fluorophenyl 2, 6-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R" = R" = hydrogen atom, L1 = fluorophenyl group], fluorophenyl 2,4,6-trif luorobenzoate [R11 = R11 = R-11 = fluorine atom, R"''1 = R11 = hydrogen atom, l/ = fluorophenyl group] , fluorophenyl 2 , 3 , 4 , 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R11 = hydrogen atom, L1 = fluorophenyl group], fluorophenyl 2 , 3 , 4 , 5 , 6-pentaf luorobenzoate [R11 = R11 = R11 = R1* = R11 = fluorine atom, L1 = fluorophenyl group], biphenyl 2-fluorobenzoate [R11 = fluorine atom, R11 = R" = R11 = R11 = hydrogen atom, l/ = biphenyl group] , biphenyl 3-fluorobenzoate [R''-1 = fluorine atom, R11 = R11 = R11 = R11 = hydrogen atom, L1 = biphenyl group] , biphenyl 4-f luorobenzoate [R11 = fluorine atom, R11 = R'"'1 = R1* = R11 = hydrogen atom, L1 = biphenyl group] , biphenyl 2,4-dif luorobenzoate [R11 = R11 = fluorine atom, R11 = R1* = R11 = hydrogen atom, L1 = biphenyl group] , biphenyl 2 , 6-dif luorobenzoate

[R""' = R"" = fluorine atom, R11 = R11 = R1* = hydrogen atom, l/ = biphenyl group], biphenyl2,4,6-trifluorobenzoate [R1- = R" = R15 = fluorine atom, R11 = R1* = hydrogen atom, l/ = biphenyl group] , biphenyl 2, 3,4, 6-tetraf luorobenzoate [R11 = R11 = R11 = R11 = fluorine atom, R1* = hydrogen atom, iJ s. biphenyl group] , biphenyl 2, 3,4, 5, 6-pentaf luorobenzoate [R11 = R11 = R11 = R" = R11 = fluorine atom, J? = biphenyl group] , etc.
[0043]
Of those, preferred are vinyl 2,4-difluorobenzoate, vinyl
2,6-difluorobenzoate, vinyl 2,4,6-trifluorobenzoate, vinyl
2,3,4,5,6-pentafluorobenzoate, 2-propenyl 2,4-difluorobenzoate,
2-propenyl 2,6-difluorobenzoate, 2-propenyl
2,4,6-trifluorobenzoate, 2-propenyl
2 , 3,4,5,6-pentafluorobenzoate, 2-propynyl 2,4-difluorobenzoate,
2-propynyl 2,6-difluorobenzoate, 2-propynyl
2,4,6-trifluorobenzoate and 2-propynyl
2,3,4,5,6-pentafluorobenzoate, as enabling increased initial capacity and enhanced cycle property. [0044] [Compound represented by general formula (IV)]
The compound to be in the nonaqueous electrolytic solution in the present invention is represented by the following general formula (IV): [0045] [Formula 9]


(IV)

(wherein R* represents a methoxy group or an ethoxy group; R1 represents a linear or branched alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 6 carbon atoms, a linear or branched alkynyl group having from 3 to 6 cajfbon atoms, a phenyl group or a biphenyl group) . 1. [0046]
R'* in the above-mentioned general formula (IV) is a methoxy group or an ethoxy group, preferably a methoxy group.
The linear or branched alkyl group having from 1 to 6 carbon atoms for R1 includes a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group, a 1-pentyl group, a tert-pentyl group, a hexyl group.
The linear or branched alkenyl group having from 2 to 6 carbon atoms for R1 includes a vinyl group, a 2-propenyl group, a 2-butenyl group, a 3-butenyl group, a 4-pentenyl group, etc.; the linear or branched alkynyl group having from 3 to 6 carbon atoms includes a 2-propynyl group, a 2-butynyl group, a 3-butynyl group, a 4-pentynyl group, a 5-hexynyl group, a 1-methyl-2-propynyl group, etc.
The phenyl group for R1 may be substituted with an alkyl group having from 1 to 6 carbon atoms or a fluorine atom, including a phenyl group, a tolyl group, a xylyl group, a mesityl group, a fluorophenyl group, etc. The biphenyl group may be substituted with an alkyl group having from 1 to 6 carbon atoms or a fluorine atom.
Of those, R1 preferably has an alkyl group having from 1 to 3 carbon atoms for the reason that the compound may form a tight film on the surface of a negative electrode to thereby prevent

the reductive decomposition of an electrolytic solution in charge-discharge cycles, most preferably having a methyl group or an ethyl group. [0047]
The ester compound represented by„_the general formula (VilV)
includes, concretely, methyl 3-methoxy-2,4,5-trifluorobenzoate
[R1 = methoxy group, R1 = methyl group] , ethyl
3-methoxy-2 , 4, 5-trif luorobenzoate [R1 = methoxy group, R1 = ethyl
group], propyl 3-methoxy-2 , 4 , 5-trif luorobenzoate [R'* = methoxy
group, R1 = propyl group] , vinyl
3-methoxy-2 , 4, 5-trif luorobenzoate [R** = methoxy group, R1 = vinyl
group], 2-propenyl 3-methoxy-2 , 4 , 5-trif luorobenzoate [R"*
methoxy group, R1 = 2-propenyl group], 2-butenyl
3-methoxy-2,4,5-trifluorobenzoate [R* = methoxy group, R1 =
2-butenyl group], 3-butenyl 3-methoxy-2,4,5-trifluorobenzoate
[R1 = methoxy group, R1 = 3-butenyl group], 4-pentenyl
3-methoxy-2,4,5-trifluorobenzoate [R* = methoxy group, R1 =
4-pentenyl group], 2-propynyl 3-methoxy-2,4,5-trifluorobenzoate
[R* = methoxy group, R1 = 2-propynyl group], 2-butynyl
3-methoxy-2,4, 5-trif luorobenzoate [R'* = methoxy group, R1 =
2-butynyl group], 4-pentynyl 3-methoxy-2,4,5-trifluorobenzoate
[R* = methoxy group, R1 = 4-pentynyl group], 5-hexynyl
3-methoxy-2,4,5-trif luorobenzoate [R** = methoxy group, R1 =
5-hexynyl group], 1-methyl-2-propynyl
3-methoxy-2,4,5-trifluorobenzoate [R1 - methoxy group, R1 =
1-methyl-2-propynyl group], phenyl
3-methoxy-2 ,4, 5-trif luorobenzoate [R1 = methoxy group, R1 = phenyl group], tolyl 3-methoxy-2 , 4 , 5-trif luorobenzoate [R'* = methoxy group, R1 = tolyl group] , xylyl 3-methoxy-2, 4, 5-trif luorobenzoate

[R^

methoxy group,

xylyl group], biphenyl

methyl
ethyl
vinyl
2-propenyl
2-propynyl
phenyl
tolyl
biphenyl
3-methoxy-2 ,4, 5-trif luorobenzoate [R'* = methoxy group, R^ -biphenyl group], etc.
are
Of those, preferred
3-methoxy-2,4,5-trifluorobenzoate,
3-methoxy-2,4,5-trifluorobenzoate,
3-methoxy-2,4,5-trifluorobenzoate,
3-methoxy-2,4,5-1ri fluorobenzoate,
3-methoxy-2,4,5-trifluorobenzoate,
3-methoxy-2,4,5-trifluorobenzoate,
3-methoxy-2,4,5-trifluorobenzoate,
3-methoxy-2 , 4 , 5-trif luorobenzoate; and more preferred are methyl
3-methoxy-2,4,5-trifluorobenzoate, and ethyl
3-methoxy-2,4,5-trifluorobenzoate. [0048] [Nonaqueous electrolytic solution]
The first nonaqueous electrolytic solution of the present invention is a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, which contains an ester compound represented by the above-mentioned general formula (III) in an amount of from 0.01 to 10 % by weight. [0049] [Formula 10]

C-0—L'
(III)
,14
R- R'
(wherein R^^ to R^^ and L^ have the same meanings as above) . [0050]

In the nonaqueous electrolytic solution of the present invention, when the content of the ester compound represented by the general formula (III) is more than 10 % by weight, then the battery capacity may lower; and when it is less than 0.01 % by weight, then the film formation may be insufficient and the initial battery capacity may be poor. Accordingly, the content of the compound is preferably at least 0.01% by weight of the nonaqueous electrolytic solution, more preferably at least 0.1 % by weight, even more preferably at least 0.2 % by weight, most preferably at least 0.3 % by weight. The uppermost limit of the content is preferably at most 10 % by weight, more preferably at most 7 % by weight, even more preferably at most 5 % by weight, most preferably at most 3 % by weight. [0051]
The second nonaqueous electrolytic solution of the present invention is a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, which contains an ester compoixnd represented by the following general formula (II) and/or (IV) , in an amount of from 0.01 to 10 % by weigh of the nonaqueous electrolytic solution. [0052] [Formula 11]

(II)
F F
(wherein R^ and L""^ have the same meanings as above)
[0053]
[Formula 12]


(wherein R* and R^ have the same meanings as above) . [0054]
In the nonaqueous electrolytic solution of the present invention, when the content of the ester compound represented by the general formula (II) and/or (IV) is more than 10 % by weight, then the battery capacity may lower; and when it is less than 0.01% by weight, then the film formation may be insufficient and the battery capacity may be poor. Accordingly, the content of the compound is preferably at least 0. 01 % by weight of the nonaqueous electrolytic solution, more preferably at least 0.1 % by weight, even more preferably at least 0.2 % by weight, most preferably at least 0.3 % by weight. The uppermost limit of the content is preferably at most 10 % by weight, more preferably at most 7 % by weight, even more preferably at most 5 % by weight, most preferably at most 3 % by weight. [0055] [Nonaqueous Solvent]
The nonaqueous solvent to be used in the nonaqueous electrolytic solution of the present invention includes cyclic carbonates, linear carbonates, linear esters, ethers, amides, phosphates, sulfones, lactones, nitriles, S=0 bond-containing compounds, etc.
The cyclic carbonates include ethylene carbonate (EC) , propylene carbonate (PC) , butylene carbonate (BC) , f luoroethylene carbonate (FEC), vinylene carbonate (VC), dimethylvinylene

carbonate, vinylethylene carbonate , etc. One or more these cyclic carbonates may be used. Especially preferably, the electrolytic solution contains at least two selected from EC, PC, VC and FEC having a high dielectric constant, as its electroconductivity .increases and the cycle property are bettered. In particular, the electrolytic solution preferably contains from 3 to 4 different types of such cyclic carbonates as combined.
The content of the cyclic carbonate is preferably within a range of from 10 to 40 % by volume of the total volume of the nonaqueous solvent. When the content is less than 10 % by volume, then the electroconductivity of the electrolytic solution lowers and the cycle property may worsen; but when the content is more than 4 0 % by volume, then the viscosity of the electrolytic solution may incerase and the cycle property may also worsen. Therefore the above-mentioned range is preferred. [0056]
The linear carbonates include asymmetric linear carbonates such as methyl ethyl carbonate (MEC), methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, ethyl propyl carbonate, etc. ; and symmetric linear carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, dibutyl carbonate, etc. Especially preferred are asymmetric carbonates, as capable of enhancing the cycle property.
One of these linear carbonates may be used; however, preferably, two or more of them are used, as combined, as capable of enhancing the cycle property.
The content of the linear carbonate is preferably within a range of from 60 to 90 % by volume of the total volume of the nonaqueous solvent. When the content is less than 60 % by volume.

then the viscosity of the electrolytic solution may incerase and the cycle property may also worsen. When the content is more than 90 % by volume, then the electroconductivity of the electrolytic solution lowers and the cycle property may worsen. Therefore the above-mentioned range is preferred. [0057]
The linear esters include methyl propionate, methyl
pivalate, butyl pivalate, hexyl pivalate, octyl pivalate,
dimethyl oxalate, ethyl methyl oxalate, diethyl oxalate, etc. The
ethers include tetrahydrofuran, 2-methyltetrahydrofuran,
1,3-dioxane, 1,4-dioxane, 1,2-dimethoxyethane,
1,2-diethoxyethane, 1,2-dibutoxyethane, etc.
The amides include dimethylformamide, etc.; the phosphates include trimethyl phosphate, tributyl phosphate, trioctyl phosphate, etc. ; the sulfones include divinyl sulfone, sulfo^lane, etc.; the lactones include y-butyrolactone, y-valerolactone, a-angelica-lactone, etc.; the nitriles include acetonitrile, succinonitrile, adiponitrile, etc. Combination of these nitriles and S=0 bond-containing compounds is preferred for use herein, as capable of enhancing the cycle property.
Specific examples of the S=0 bond-containing compounds include 1,3-propanesultone (PS), 1,4-propanesultone, 1,3-butanediol dimethanesulfonate, 1,4-butanediol dimethanesulfonate, divinylsulfone, ethylene sulfite, propylene sulfite, vinylethylene sulfite, vinylene sulfite, methyl 2-propynyl sulfite, ethyl 2-propynyl sulfite, dipropynyl sulfite, cyclohexyl sulfite, ethylene sulfate, propylene sulfate, etc. [0058]
In general, the above-mentioned nonaqueous solvents are

combined for use herein for the purpose of attaining suitable physical properties. The combination includes, for example, a combination of cyclic carbonate and linear carbonate; a combination of cyclic carbonate, linear carbonate and lactone; a combination of cyclic carbonate, linear carbonate and-ether; a combination of cyclic carbonate, linear carbonate and linear ester, etc.
Of those, preferred is a combination of cyclic carbonate and linear carbonate, concretely a combination of a cyclic carbonate such as EC, PC, VC, FEC or the like, and a linear carbonate such as DMC, MEC, DEC or the like, as capable of enhancing the cycle property.
The blend ratio of cyclic carbonate and linear carbonate is preferably from 10/90 to 40/60 as a ration of cyclic carbonate/linear carbonate (by volume) , from the viewpoint of the ability of enhancing the cycle property, more preferably from 15/85 to 35/65, even more preferably from 20/80 to 30/70. [0059] [Electrolyte Salt]
The electrolyte for use in the present invention includes Li salts such as LiPFg, LiBF4, LiCl04, etc.; linear fluoroalkyl group-having lithium salts such as LiN(S02CF3) 2, LiN(S02C2F5) 2, LiCFaSOa, LiC (SO2CF3) 3 , LiPF4(CF3)2, LiPF3 (C2F5) 3 , LiPF3(CF3)3, LiPFs (iso-C3F7)3, LiPFg (iso-C3F7) , etc.; and cyclic f luoroalkylene chain-having lithium salts such as (CFz) 2 (SO2) 2NLi, (CF2) 3 (SO2) 2NLi, etc. Of those, especially preferred electrolyte salts are LiPFg, LiBF4, LiN(S02CF3) 2, LiN(SO2C2F5) 2; and most preferred electrolyte salts are LiPFg, LiBF4 and LiN (SO2CF3) 2 - One or more of these electrolyte salts may be used herein either singly or as combined.

[0060]
A preferred combination of these electrolyte salts is a combination containing LiPFg as combined with at least one selected from LiBF4, LiN(S02CF3)2 and LiN (SO2C2F5) 2. Preferred are a combination of LiPFg and LiBF4; -a combination of LiPFs and LiN(S02CF3) 2; a combination of LiPFg and LiN (SO2C2F5) 2, etc. When the ratio (by mol) of LiPF6/LiBF4 or LiN(S02CF3)2 or LiN(S02C2F5) 2 is smaller than 70/30 in point of the proportion of LiPFg, or when the ratio is larger than 99/1 in point of the proportion of LiPFg, then the cycle property may worsen. Accordingly, the ratio (by mol) of LiPF6/LiBF4 or LiN(S02CF3)2 or LiN(S02C2F5) 2 is preferably within a range of from 70/30 to 99/1, more preferably from 80/20 to 98/2. The combination falling within the above range can enhance the cycle property.
The electrolyte salts may be combined in any desired ratio. In the combination of LiPFg with any of LiBF4, LiN(S02CF3)2 and LiN(S02C2F5) 2, when the proportion (as ratio by mol) of the other electrolyte salt than those ingredients to the total electrolyte salts is less than 0.01 %, then the high-temperature storage stability of the electrolyte mixture may be poor; but when it is more than 45 %, then the high-temperature storage stability thereof may worsen. Accordingly, the proportion (as ratio by mol) is preferably from 0.01 to 45 %, more preferably from 0.03 to 20 %, even more preferably from 0.05 to 10 %, most preferably from 0.05 to 5 %.
The concentration of all these electrolyte salts as dissolved in the solution is generally preferably at least 0.3 M relative to the above-mentioned nonaqueous solvent, more preferably at least 0.5 M, most preferably at least 0.7 M. The

uppermost limit of the concentration is preferably at most 2.5
M, more preferably at most 2.0 M, even more preferably at most
1.5 M, most preferably at most 1.2 M.
[0061]
[Other Additives]
An aromatic compound may be added to the nonaqueous
electrolytic solution of the present invention, thereby securing
the safety of the battery in overcharging. Preferred examples of
the aromatic compound include cyclohexylbenzene,
fluorocyclohexylbenzene compound (1-fluoro-2-cyclohexylbenzene,
1-fluoro-3-cyclohexylbenzene, 1-fluoro-4-cyclohexylbenzene),
tert-butylbenzene, tert-amylbenzene,
l-fluoro-4-tert-butylbenzene, 1, 3-di-tert-butylbenzene,
biphenyl, terphenyl (o-, m-, p-), diphenyl ether, fluorobenzene,
difluorobenzene (o-, m-, p-), 2,4-difluoroanisole, terphenyl
partial hydrolyzate (1,2-dicyclohexylbenzene,
2-phenylbicyclohexyl, 1, 2-diphenylcyclohexane,
o-cyclohexylbiphenyl) , etc. One or more of these aromatic compo\inds may be used either singly or as combined. [0062] [Production of Nonaqueous Electrolytic solution]
The nonaqueous electrolytic solution of the present invention can be produced, for example, by mixing the above-mentioned nonaqueous solvents followed by dissolving therein the above-mentioned electrolyte salt and at least one compound selected from those of the above-mentioned general formulae (II), (III) and (IV) in an amount of from 0.01 to 10 % by weight of the resulting nonaqueous electrolytic solution.
In this case, the compounds to be added to the nonaqueous

solvent and the electrolytic solution are preferably previously purified within a range not significantly detracting from the producibility, in which, therefore, the impurity content is as low as possible.
For example, air or carbon dioxide may be incorporated into the nonaqueous electrolytic solution of the present invention to thereby prevent gas generation resulting from decomposition of electrolytic solution and to enhance the battery characteristics such as the long-term cycle property and the storage property in a charged state.
In the present invention, from the viewpoint of enhancing charging and discharging characteristics at high temperatures, the nonaqueous electrolytic solution preferably contains carbon dioxide as dissolved therein. The amount of carbon dioxide to be dissolved in the nonaqueous electrolytic solution is preferably at least 0.001 % by weight of the solution, more preferably at least 0.05 % by weight, even more preferably at least 0.2 % by weight; and most preferably, carbon dioxide is dissolved in the nonaqueous electrolytic solution until its saturation therein. [0063] [Lithium Secondary Battery]
The lithium secondary battery of the present invention comprises a positive electrode, a negative electrode and the above-mentioned nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent. The other constitutive components such as a positive electrode and a negative electrode except for the nonaqueous electrolytic solution can be used with no limitation.
For example, as the positive electrode active material.

usable are complex metal oxides of lithium containing any of cobalt, manganese or nickel. One or more such positive electrode active materials may be used either singly or as combined.
The complex metal oxides include, for example, LiCo02, LiMn204, LiNiOs, LiCoi-xNix02 (0.01 < x < 1), LiCOi/sNii/aMni/aOs, LiNii/2Mn3/204, LiCoo.98Mgo.02O2, etc. Combinations of LiCo02 and LiMn204 ; LiCo02 and LiNi02; LiMn204 and LiNi02 are acceptable herein. [0064]
For enhancing safety in overcharging or cycle property, the lithium complex oxide may be partly substituted with any other element for enabling the use of the battery at a charging potential of 4.3 V or more. A part of cobalt, manganese and nickel may be substituted with at least one element of Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, Cu, Bi, Mo, La, etc.; or 0 may be partly substituted with S or F; or the oxide may be coated with a compound containing such other element.
Of those, preferred are lithium complex metal oxides such as LiCo02, LiMn204 and LiNi02, with which the positive electrode charging potential in a full-charging state may be 4.3 V or more, based on Li. More preferred are lithium complex oxides usable at 4.4 V or more, such as LiCoi-xMx02 (where M is at least one element of Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn and Cu; 0. 001 < x < 0. 05) , LiCoi/3Nii/3Mni/302, and LiNii/2Mn3/204. When a lithium/transition metal complex oxide having a high charging potential is used, then gas may be generated through reaction with electrolytic solution in charging; however, the lithium secondary battery of the present invention can prevent such gas generation. [0065]
Further, lithium-containing olivine-type phosphates are

also usable as the positive electrode active material. Their concrete- examples include LiFeP04, LiCoP04, LiNiP04, LiMnP04, LiFei-xMxP04 (M is at least one selected from Co, Ni, Mn, Cu, Zn,
Nb, Mg, Al, Ti, W, Zr and Cd; and 0 < x < 0.5), etc. Of those, preferred are LiFeP04 and LiCoP04.
The lithium-containing olivine-type phosphate may be combined with, for example, the above-mentioned positive electrode active material. [0066]
Not specifically defined, the electroconductive agent of the positive electrode may be any electron-transmitting material not undergoing chemical change. For example, it includes graphites such as natural graphite (flaky graphite, etc.), artificial graphite, etc. ; carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, etc . Graphites and carbon blacks may be combined suitably. The amount of the electroconductive agent to be added to the positive electrode mix is preferably from 1 to 10 % by weight, more preferably from 2 to 5 % by weight. [0067]
The positive electrode may be formed by mixing the above-mentioned positive electrode active material with an electroconductive agent such as acetylene black, carbon black or the like, and with a binder such as polytetrafluoroethylene (PTFE) , polyvinylidene fluoride (PVDF), styrene/butadiene copolymer (SBR) , acrylonitrile/butadiene copolymer (NBR), carboxymethyl cellulose (CMC), ethylene/propylene/diene terpolymer or the like, then adding thereto a high-boiling-point solvent such as l-methyl-2-pyrrolidone or the like, and kneading them to give a

positive electrode mix, thereafter applying the positive electrode mix onto an aluminium foil or a stainless lath plate or the like serving as a collector, and drying and shaping it under pressure, and then heat-treating it in vacuum at a temperature of from 50°C to 250°C or so for about 2 hours. [0068]
As the negative electrode active material, usable are one or more of lithium metal, lithium alloys, carbon materials and metal compounds capable of absorbing and releasing lithium, as combined.
Of those, preferred are high-crystalline carbon materials such as artificial graphite, natural graphite or the like of which the ability of absorbing and releasing lithium ions is good. More preferred is a carbon material having a graphite-type crystal structure where the lattice (002) spacing (doo2) is at most 0.340 nm (nanometers), especially from 0.335 to 0.337 nm. More preferably, the high-crystalline carbon material is coated with a low-crystalline carbon material, as capable of more effectively preventing gas generation. When such a high-crystalline carbon material is used, then it may react with an electrolytic solution in charging to generate gas,- however, the lithium secondary battery of the present invention can prevent the reaction.
The metal compound capable of absorbing and releasing lithium, serving as a negative electrode active material, includes compounds containing at least one metal element of Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, Sr, Ba, etc. These metal compounds may have any morphology of simple substances, alloys, oxides, nitrides, sulfides, borides, alloys with lithium or the like; but preferred are any of simple

substances, alloys, oxides and alloys with lithium, as capable of increasing the battery capacity. Above all, more preferred are those containing at least one element selected from Si, Ge and Sn, and even more preferred are those containing at least one element selected from Si and Sn, as capable of increasing the capacity of the battery.
The negative electrode may be formed, using the same electroconductive agent, binder and high-boiling point solvent as in the formation of the above-mentioned positive electrode. These are mixed and kneaded to give a negative electrode mix, then the negative electrode mix is applied onto a copper foil or the like serving as a collector, then dried and shaped under pressure, and thereafter heat-treated in vacuum at a temperature of from
50°C to 250°C or so for about 2 hours.
[0069]
In the present invention, preferably, the electrode mixture density is increased for the purpose of enhancing the effect of the ester compound of the above-mentioned general formula (II),
(III) and (IV) added to the mixture . In particular, when a lithium complex metal oxide with any of cobalt, manganese or nickel is used as the active material for the positive electrode to be formed on an aluminium foil, then the density of the positive electrode
(positive electrode mixture layer) is preferably at least 3 .2 g/cm^, more preferably at least 3.3 g/cm'', most preferably at least 3.4 g/cm^. When its uppermost limit is over 4.0 g/cm'', then the electrode is substantially difficult to form. Accordingly, the uppermost limit is preferably at most 4.0 g/cm^, more preferably at most 3.9 g/cm^, most preferably at most 3.8 g/cm^.
When a lithium-containing olivine-type phosphate is used

as the positive electrode active material, then the density of the positive electrode (positive electrode mixture layer) is preferably at least 1.3 g/cm^, more preferably at least 1.4 g/cm^, most preferably at least 1.5 g/cm^. When its uppermost limit is over 4.0 g/cm^, then the electrode is substantially difficult to form. Accordingly, the uppermost limit is preferably at most 4.0 g/cm^, more preferably at most 3.5 g/cm^, most preferably at most 3.0 g/cm^.
On the other hand, the density of the negative electrode (negative electrode mixture layer) formed on a copper foil is preferably at least 1.3 g/cm^, more preferably at least 1.4 g/cm^, most preferably at least 1.5 g/cm^. When its uppermost limit is over 2.0 q/cm^, then the electrode is substantially difficult to form. Accordingly, the uppermost limit is preferably at most 2.0 g/cm^, more preferably at most 1.9 g/cm^, most preferably at most 1.8 g/cm^. [0070]
Regarding the thickness of the positive electrode layer (per one surface of collector), when the thickness of the electrode material layer is too thin, then the active material amount in the electrode material layer may lower and the battery capacity may be low. Accordingly, the thickness is preferably at least 3 0 |a.m, more preferably at least 50 |j,m. However, when the thickness is too large, then it is unfavorable since the cycle property and the rate property of the battery may worsen. Accordingly, the thickness of the positive electrode layer is preferably at most
120 fim, more preferably at most 100 ^m.
When the thickness of the negative electrode layer (per one surface of collector) is too thin, then the active material amount

in the electrode material layer may lower and the battery capacity may be low. Accordingly, the thickness is preferably at least 1
|Lim, more preferably at least 3 fim. However, when the thickness is too large, then it is unfavorable since the cycle property and the rate property of the battery may worsen. Accordingly, the thickness of the negative electrode layer is preferably at most
100 ^m, more preferably at most 70 |am. [0071]
Also preferably, the positive and negative electrodes in
the present invention may be in such a form that the corresponding
electrode mixtures are separately applied onto each surface of
a collector. In this case, the layer on one surface maybe a single
layer or a multiple layer. In case where the layer on one surface
is a multiple layer, it may comprise two or more, positive electrode
active material (or negative electrode active
material)-containing layers. A more preferred constitution
comprises a positive electrode active material (or negative
electrode active material)-containing layer and a positive
electrode active material (or negative electrode active
material)-free layer, in which the positive electrode active
material (or negative electrode active material)-free layer may
be a protective layer for protecting the positive electrode active
material (or negative electrode active material) -containing layer,
or an interlayer to be between the divided positive electrode
active material (or negative electrode active
material)-containing layer, or an underlayer to be between the
positive electrode active material (or negative electrode active
material)-containing layer and the collector, etc. In the present
invention, all these are generically referred to as an auxiliary

layer.
When the thickness of the auxiliary layer (per one surface) is too thin, the decomposition of the electrolytic solution could not be prevented; and therefore, the thickness is preferably at
least 1 |j,m, more preferably at least .3 |im. However, when the thickness is too large, then it is unfavorable since the layer may interfere with ion movement and the cycle property and the rate property may be thereby worsened. Accordingly, the thickness of the auxiliary layer is preferably at most 20 [im, more preferably at most 10 |j,m. [0072]
Especially preferably in the present invention, the battery structure has a protective layer for the purpose of enhancing the effect of the ester compoundof the above-mentioned general formula (II), (III) and (IV) added thereto. Preferably, the protective layer is on both of the positive and negative electrode or on any of the positive and negative electrode; and more preferably, the protective layer is to protect the negative electrode. The protective layer comprises at least one layer, and may comprise plural layers that are the same or different. The protective layer may be formed of water-insoluble particles, a binder, etc., in which the binder may be the same as that for use in producing the above-mentioned electrode mixture. The water-insoluble particles are preferably those poorly reactive with alkali metal, especially lithium, for which usable is at least one type of various electroconductive particles, substantially non-conductive organic or inorganic particles. The proportion of the insoluble particles to be in the protective layer is preferably from 2.5 % by weight to 99 % by weight, more preferably from 5 % by weight

to 98 % by weight. [0073]
The water-insoluble electroconductive particles include metals, metal oxides, metal fibers, carbon fibers, and carbon particles of carbon black, graphite or the like. The
non-conductive water-insoluble particles include Teflon® fine powders, SiC, aluminium nitride, alumina, zirconia, magnesia, mullite, forsterite, steatite, etc. Of those water-insoluble particles, especially preferred are ceramic particles of SiC, aluminium nitride, alumina, zirconia, magnesia, mullite, forsterite, steatite or the like; and these may be used either singly or as combined with carbon particles for making the protective layer electroconductive. The carbon particles to be used as the electroconductive material may be any known carbon materials. Concretely, usable are the electroconductive agents that are used in preparing the electrode mixture . Regarding their morphology, the particles may be needle-like, columnar, tabular or massive; and preferably, their maximum diameter is from 0.02
|im to 20 jim, more preferably from 0.1 |im to 10 fim. [0074]
The lithium secondary battery can have any structure without restriction. The secondary battery may be a coin-shaped battery, a cylindrical battery, a square-shaped battery, or a laminate-type battery, each having a single layered or multi-layered separator.
The battery separator may be composed of a single layered or laminated porous film, woven fabric, or non-woven fabric of a polyolefin such as polypropylene or polyethylene.
A separator having a significantly high Gurley value (air permeability) may lead to a reduction in lithium ion conductivity

and thus does not sufficiently function as a battery separator, although it depends on fabrication conditions. Therefore, the Gurley value is preferably 1000 seconds/100 cc or lower, more preferably 800 seconds/100 cc or lower, and most preferably 500 seconds/100 cc or lower. A significantly low Gurley value of the battery separator may lead to low mechanical strength. Therefore, the Gurley value is preferably 50 seconds/100 cc or more, more preferably 100 seconds/100 cc or more, and most preferably 300 seconds/100 cc or more. The porosity of the separator preferably ranges from 30% to 60%, more preferably from 35% to 55%, and most preferably from 40% to 50%, from the viewpoint of improvements in capacity characteristics of the battery.
Furthermore, a higher energy density is achieved by a smaller thickness of the separator. Thus, the thickness of the battery separator is preferably 50 jim or less, more preferably 40 |im or less, and most preferably 2 5 fim or less. Also, in order to ensure sufficient mechanical strength, the thickness of the battery
separator is preferably 5 |j,m or more, more preferably 10 |im or more, and most preferably 15 [xm or more. [0075]
The lithium secondary battery of the present invention exhibits excellent long-term cycle property even when the final charging voltage is 4 . 2 V or higher and particularly 4 . 3 V or higher. Furthermore, the cycle property are favorable even when the final charging voltage is 4.4 V. The final discharging voltage can be set to 2 . 5 V or more and preferably 2.8 V or more. Although the current value is not restricted, a constant current discharge of . 0. IC to 3C is generally employed. The lithium secondary battery of the present invention may be charged and discharged at -40°C

to 100°C and preferably 0°C to 80°C.
[0076]
In the present invention, a sealing plate may be provided with a relief valve, as a countermeasure against an increase in internal pressure of the lithium secondary battery. Alternatively, a cutout may be provided in a battery component such as a battery can or a gasket.
In the lithium secondary battery of the present invention, a plurality of lithium secondary batteries may be accommodated in a battery pack in series and/or in parallel, as necessary. The battery pack can be provided with an overcurrent circuit breaker, such as a PTC element, a thermal fuse, or a bimetal, as well as a safety circuit (a circuit that can monitor the voltage, the temperature, and the current of each battery and/or the entire battery pack, and can shut off the current, as necessary), [Examples] [0077]
Production Examples for the ester compounds of the present invention, and Examples of using the electrolytic solution of the present invention are given below.
Production Example 1 [Production of vinyl 3-methoxy-2,4,5-trifluorobenzoate (Compound-2)] [0078] [Formula 13]

Compound-2 [0079]
0

3-Methoxy-2,4,5-trifluorobenzoic acid (MTFBA) (10.19 g, 0.0494 mol), vinyl acetate (85.1 g, 0.989 mol), palladium acetate (1.66 g, 0.00741 mol), and potassium hydroxide (0.277 g, 0.00494
mol) were stirred at 40°C for 24 hours. The reaction mixture was filtered, the filtrate was washed with saturated NaHCOa solution, then washed with brine, dried with MgS04, and concentrated with an evaporator to give a vinyl ester (5.89 g, yield: 51 %) . This
was purified through vacuum distillation (135°C/1.5 Torr), and used in the battery evaluation test.
The structure of the obtained vinyl 3-methoxy-2,4,5-trifluorobenzoate was confirmed through ^H-NMR and ^^C-NMR (using JEOL's Model AL300) and through mass spectrometry (using Hitachi's Model MSOB) . The results are shown below.
(1) ^H-NMR (300 MHz, CDCI3) : 5 = 7.9-7.4 (m, 1 H) , 5.1 (dxd, J =
7.0x1.0 Hz, 1 H) , 4.8 (dxd, J = 3.1x0.9 Hz, lH),4.1(t, J=1.2
Hz, 3 H).
(2) "C-NMR (75 MHz, CDCI3) 6 = 159.7-159.6 (m), 154.4-145.2 (m), 141.0, 112.4-112.1 (m), 99.4, 62.3 (t, J - 3.7 Hz).
(3) mass spectrometry : MS(EI) m/z(%) = 232(10) [M"] , 189(100), 161(27), 146(31), 113(22), 81(9), 43(4), 18(8).
[0080]
Production Example 2 [Production of allyl
3-raethoxy-2,4,5-trifluorobenzoate (Compound-3)]
[0081]
[Formula 14]


MTFBA (20.42 g, 0.0991 mol) and dimethylformamide (hereinafter referred to as "DMF") (0.0724 g, 0.991 mmol) were dissolved in toluene (100 mL), and thionyl chloride (23.56 g, 0.198 mol) was dropwise added thereto at 70°C, taking 60 minutes. After the addition, this was stirred at 70°C for 2 hours to confirm the disappearance of MTFBA, and then toluene and the excessive thionyl chloride were removed under reduced pressure, thereby preparing an acid chloride of MTFBA. In a separate reactor, allyl alcohol (6.04 g, 0.104 mol), triethylamine (10.5 g, 0.102 mol) and toluene (30 mL) were mixed, and the prepared acid chloride of MTFBA was
dropwise added thereto at 0°C. After the addition, this was stirred at room temperature for 1 hour, then washed with aqueous saturated NaHCOs solution, and extracted with ethyl acetate. The organic layer was washed twice with brine, then dried with MgS04, and concentrated with an evaporator to give an allyl ester (20.5 g, yield: 84 %) . This was purified through vacuum distillation
(108°C/2 Torr), and used in the battery evaluation test.
The structure of the obtained allyl 3-methoxy-2,4,5-trifluorobenzoate was confirmed in the same manner as above. The disappearance of MTFBA was confirmed by sampling a predetermined amount of a part of the reaction liquid, adding methanol thereto and quantitatively determining the resulting methyl ester through HPLC (the same shall apply to the following Production Examples). The results are shown below.

(1) ^H-NMR (300 MHz, CDCI3): 5 = 7.5-7.4 (m, 1 H) , 6.1-5.9 (m, 1
H) , 5.4 (dxq, J = 7.5x1.5 Hz, 1 H) , 5.3 (dxq, J = 5.2x2.1 Hz, 1
H), 4.8 (dxt, J = 2.8x1.5 Hz, 2 H), 4.1 (t, J = 1.2 Hz, 3 H).
(2) ^^C-NMR (75 MHz, CDCI3) 5 = 162.4, 154.0-153. 9 (m) , 150.6-145.1
(m) , 131.5, 118.9, 112.3-112.0 (m), 66.4, 62.3 (t, J = 3,1 Hz).
(3) mass spectrometry: MS (EI) m/z(%) = 246(11) [M^] , 189(100),
116(7), 146(8), 118(7), 81(3), 41(26), 39(15), 18(6).
[0083]
Production Example 3 [Production of propargyl
3-methoxy-2,4,5-trifluorobenzoate (Compound-4)]
[0084]

MTFBA (20.11 g, 0.0976 raol) and DMF (0.0713 g, 0.976 mmol) were dissolved in toluene (100 mL), and thionyl chloride (23.21 g, 0 .195 mol) was dropwise added thereto at 70°C, taking 60 minutes . After the addition, this was stirred at 70°C for 2 hours to confirm the disappearance of MTFBA, and then toluene and the excessive thionyl chloride were removed under reduced pressure, thereby preparing an acid chloride of MTFBA. In a separate reactor, propargyl alcohol (5.72 g, 0.102 mol), triethylamine (10.3 g, 0.102 mol) and toluene (30 mL) were mixed, and the prepared acid chloride
of MTFBA was dropwise added thereto at 0°C. After the addition, this was stirred at room temperature for 1 hour, then washed with water in the same manner as in Production Example 2, thereby giving

a propargyl ester (21.4 g, yield: 90 %) . This was purified through
vacuum distillation. (93°C/l Torr) , and used in the battery-evaluation test.
The structure of the obtained propargyl 3-methoxy-2,4,5-trifluorobenzoate .was confirmed in the same manner as above. The results are shown below.
(1) ^H-NMR (300 MHz, CDCI3) : 5 = 7.6-7.5 (m, 1 H) , 4.9 (d, J = 2.4
Hz, 2 H), 4.1 (t, J = 1.1 Hz, 3 H), 2.6 (t, J = 4.9 Hz, 1 H).
(2) "C-NMR (75 MHz, CDCI3) : 5 = 161. 9 , 154 . 2-145 . 2 (m) , 112.4-112.0
(m), 77.0, 75.6, 62.3 (t, J = 3.4 Hz), 53.1.
(3) mass spectrometry : MS (EI) m/z(%) = 224(17) [M""] , 189(100),
161(10), 146(11), 99(11), 68(9), 39(49), 18(14).
[0086]
Production Example 4 [Production of phenyl 3-methoxy-2,4,5-trifluorobenzoate (Compound-5)] [0087]

MTFBA (21.33 g, 0.104 mol) and DMF (0.0755 g, 1.04 mmol) were dissolved in toluene (100 mL), and thionyl chloride (24.7 g, 0.208 mol) was dropwise added thereto at 70°C, taking 60 minutes . After the addition, this was stirred at 70°C for 2 hours to confirm the disappearance of MTFBA, and then toluene and the excessive thionyl chloride were removed under reduced pressure, thereby preparing an acid chloride of MTFBA. In a separate reactor, phenol

(10.2 g, 0.109 mol), triethylamine (11.02 g, 0.109 mol) and toluene (45 mL) were mixed, and the prepared acid chloride of MTFBA was
dropwise added thereto at 0°C. After the addition, this was stirred at room temperature for 1 hour, then washed with water in the same manner as in Production Example 2, thereby giving a. phenyl ester (25.1 g, yield: 86 %) . This was purified through
vacuum distillation (169°C/1.5 Torr), and used in the battery evaluation test.
The structure of the obtained phenyl 3-methoxy-2,4,5-trifluorobenzoate was confirmed in the same manner as above. The results are shown below.
(1) ^H-NMR (3 00 MHz, CDCI3) : 5= 7.6-7.2 (m, 6H), 4.1 (t, J= 1.2
Hz, 3 H).
(2) "C-NMR (75 MHz, CDCI3) : 5 = 161.2, 154.4-145.2 (m) , 153.4,
129.6, 126.4, 121.5, 112.6-112.3 (m), 62.4 (t, J = 3.8 Hz).
(3) mass spectrometry : MS (EI) m/z(%) = 282(9) [M""] , 189(100),
161(9), 146(10), 113(6), 81(3), 39(9).
[0089]
Production Example 5 [Production of biphenyl
3-methoxy-2,4,5-trifluorobenzoate (Compound-6)]
[0090]

MTFBA (21.33 g, 0.104 mol) and DMF (0.0755 g, 1.04 mmol) were dissolved in toluene (100 mL), and thionyl chloride (24.7

g, 0.208 mol) was dropwise added thereto at 70°C, taking 6 0 minutes. After the addition, this was stirred at 70°C for 2 hours to confirm the disappearance of MTFBA, and then toluene and the excessive thionyl chloride were removed under reduced pressure, thereby preparing an acid chloride of MTFBA. In a separate reactor, 4-phenylphenol (18.6 g, 0.109 mol), triethylamine (11.02 g, 0.109 mol), toluene (45 mL) and ether (45 mL) were mixed, and the prepared
acid chloride of MTFBA was dropwise added thereto at 0°C. After the addition, this was stirred at room temperature for 1 hour, then washed with aqueous 5 %-NaOH solution, and extracted with ethyl acetate. The organic layer was washed twice with brine, dried with MgS04, and concentrated with an evaporator thereby giving a biphenyl ester (7.8 g, yield: 21 %) . This was purified through crystallization with a solvent of dimethyl carbonate
(white powder, m.p. 94°C) , and used in the battery evaluation test. The structure of the obtained biphenyl 3-methoxy-2,4,5-trifluorobenzoate was confirmed in the same manner as above. The results are shown below.
(1) ^H-NMR (300 MHz, CDCI3) : 5 - 7.7-7.3 (m, 10 H) , 4.1 (t, J = 1.1 Hz, 3 H).
(2) ^^C-NMR (75 MHz, CDCI3) : 5 = 161.2, 154.2-145.2 (m) , 149.8, 14 0.2, 13 9.5, 128.3, 128.3, 127.5, 127.2, 112.5 (d, J = 10.6 Hz) , 62.4 (d, J = 3.7 Hz).
(3) mass spectrometry: MS (EI) m/z(%) = 358(20) [M*] , 189(100), 161(7), 146(8), 115(11), 63(4).
[0092]
Production Example 6 [Production of 2-butyne-l,4-diol
bis(3-methoxy-2,4,5-trifluorobenzoate) (Compound-7)]
[0093]


MTFBA (15.07 g, 0.073 mol) and DMF (0.0637 g, 0.731 mmol) were dissolved in toluene (50 mL), and thionyl chloride (13.04 g, 0 .110 mol) was dropwise added thereto at 70°C, taking 60 minutes . After the addition, this was stirred at 70°C for 2 hours to confirm the disappearance of MTFBA, and then toluene and the excessive thionyl chloride were removed under reduced pressure, thereby preparing an acid chloride of MTFBA. In a separate reactor, 2-butyne-l,4-diol (3.12 g, 0.036 mol), triethylamine (7.86 g, 0.078 mol) and toluene (100 mL) and were mixed, and the prepared
acid chloride of MTFBA was dropwise added thereto at 0°C. After
the addition, this was stirred at room temperature for 1 hour,
then washed with water in the same manner as in Production Example
2, thereby giving 2-butyne-l,4-diol
bis(3-methoxy-2,4,5-trifluorobenzoate) (16.6 g, yield: 99 %) . This was purified through crystallization with a solvent of
dimethyl carbonate (white powder, m.p. 96°C) , and used in the battery evaluation test.
The structure of the obtained 2-butyne-l,4-diol bis (3-methoxy-2 , 4 , 5-trif luorobenzoate) was confirmed in the same manner as above. The results are shown below.
(1) ^H-NMR (300 MHz, CDCI3) : 6 =7.6-7.5 (m, 2 H) , 4.9 (s, 4 H) ,
4.1 (t, J = 1.2 Hz, 6 H) .
(2) IR (KBr method): 1730, 1621, 1504, 1479, 1438, 1384, 1353,

1276, 1222, 1102, 357, 784, 569 cm"^.
(3) mass spectrometry: MS (EI) m/z (%) = 462 (5) [M"] , 418 (4) , 257 (4) , 189(100) , 146 (5) , 32 (4) . [0095]
Example A-1: [Preparation of electrolytic solution]
LiPFg to be 0 . 95 M and LiN(S02CF3) 2 to be 0 . 05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) = 18/10/2/35/35 (by volume); and further the following Compound-1 was added thereto in an amount of 2 % by weight, thereby preparing a nonaqueous electrolytic solution. [0096]

[Production of Lithium Ion Secondary Battery]
LiCoi/3Mni/3Nii/302 (positive electrode active material) (92% by weight), acetylene black (electroconductive agent) (3 % by weight) and polyvinylidene fluoride (binder) (5 % by weight) were mixed in that ratio, then a solvent of 1-methyl-2-pyrrolidone was added thereto and mixed. The resulting mixture was applied onto an aluminium foil collector, dried, processed under pressure and cut into a predetermined size, thereby producing a long rectangular, positive electrode sheet. Artificial graphite (negative

electrode active material) (95 % by weight) and polyvinylidene fluoride (binder) (5 % by weight) were mixed in that ratio, and a solvent of l-methyl-2-pyrrolidone was added thereto and mixed. The resulting mixture was applied onto a copper foil collector, dried, processed under pressure and cut into a predetermined size, thereby producing a long rectangular, negative electrode sheet. The positive electrode sheet, a porous polyethylene film separator, the negative electrode sheet and a separator were laminated in that order, and the resulting laminate was coiled up. The coil was housed into a nickel-plated, iron cylindrical battery can serving also as a negative electrode terminal. Further, the electrolytic solution was injected thereinto, and the can was calked with a battery cap having a positive electrode terminal, via a gasket therebetween, thereby constructing a cylindrical battery having a designed capacity of 2200 mAh. The positive electrode terminal was connected to the positive electrode sheet via an aluminium lead tab therebetween; and the negative electrode can was previously connected to the negative electrode sheet inside the battery, via a nickel lead tab therebetween. [0098]
[Determination of Battery Characteristics] [Determination of Cycle Property]
In a thermostat chamber kept at 25°C, the battery constructed according to the above-mentioned method was charged up to a terminal voltage of 4.35 V for 7 hours with a constant current and a constant voltage of 44 0 mAh (0.2 C) , then this was discharged to a discharge voltage of 2 . 7 V under the constant current of 440 mAh (0.2 C), and the initial capacity of the battery was thus determined. The battery of which the initial capacity had been

determined was further charged, in a thermostat chamber kept at
45°C, up to a terminal voltage of 4.35 V for 3 hours with a constant current and a constant voltage of 2200 mAh (1 C), then this was discharged to a discharge voltage of 2.7 V under the constant current of 2200 mAh (1 C) . This is one cycle. The bajttery was subjected to 100 cycles. After the cycle test, the capacity retention of the battery was determined according to the following formula. As a result, the capacity retention of the battery after 100 cycles was 90 %. Capacity Retention (%) = (discharge capacity after 100
cycles/discharge capacity in 1 cycle) x 100. [0099] Examples A-2 to A-7:
Like in Example A-1, LiPFg to be 0.95 M and LiN(S02CF3)2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) 18/10/2/35/35 (by volume), and in place of adding Compound-1 thereto, any of Compound-2 to Compound-7 was added thereto in an amount of 2 % by weight, thereby preparing a nonaqueous electrolytic solution. Using this, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table A-1. [0100] Examples A-8 to A-11:
Like in Example A-1, LiPFg to be 0.95 M and LiN(S02CF3)2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC)

18/10/2/35/35 (by volume), and Compound-1 was added thereto in an amount of 0.01 % by weight, 1 % by weight, 5 % by weight or 10 % by weight, thereby preparing a nonaqueous electrolytic solution. Using this, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table A-1. [0101] Comparative Example A-1:
Like in Example A-1, LiPFs to be 0.95 M and LiN(S02CF3)2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) 18/10/2/35/35 (by volume) ; however, Compound-1 was not added thereto. Using the thus-prepared nonaqueous electrolytic solution, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table A-1. [0102] Comparative Examples A-2 and A-3:
Like in Example A-1, LiPFe to be 0.95 M and LiN(S02CF3)2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) 18/10/2/35/35 (by volume), and in place of adding Compound-1 thereto, any of the following Comparative Compound-1 or 2 was added thereto in an amount of 2 % by weight, thereby preparing a nonaqueous electrolytic solution. Using this, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table A-1.

preparing a nonaqueous electrolytic solution. Using this, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table A-2. [0106] Comparative Example A-4:
Like in Example A-12, LiPFg to be 0 . 95 M and LiN(S02CF3)2 to be 0.0 5 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/fluoroethylene carbonate (FEC)/vinylene carbonate (VC)/methyl ethyl carbonate (MEC) = 3/10/15/2/70 (by volume); however, Compound-1, adiponitrile and cyclohexyl sulfite were not added thereto. Using the thus-prepared nonaqueous electrolytic solution, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table A-2. [0107] [Table 2]

[0108]
Examples A-1 to A-12 of the present invention where the negative electrode is made of graphite confirm excellent cycle property; and it has been found that, not limited to the graphite negative electrode, the electrolytic solution of the present

invention is also effective for a silicon negative electrode, a tin negative electrode and an Li negative electrode, in enhancing the cycle property like in these Examples. [0109] Example B-1:
Using LiFeP04 (positive electrode active material) in place of the positive electrode active material used in Example A-1, a positive electrode sheet was produced. LiFeP04 (positive electrode active material) (90 % by weight), acetylene black (electroconductive agent) (5 % by weight) and polyvinylidene fluoride (binder) (5 % by weight) were mixed in that ratio, then a solvent of l-methyl-2-pyrrolidone was added thereto and mixed. The resulting mixture was applied onto an aluminium foil collector, dried, processed under pressure and cut into a predetermined size, thereby producing a long rectangular, positive electrode sheet. The positive electrode sheet, a porous polyethylene film separator, a negative electrode sheet and a separator were laminated in that order, and the resulting laminate was coiled up. The coil was housed into a nickel-plated, iron-made cylindrical battery can serving also as a negative electrode terminal. Further, the electrolytic solution prepared in Example A-1 was injected thereinto, and the can was calked with a battery cap having a positive electrode terminal, via a gasket therebetween, thereby constructing a cylindrical battery having a planned capacity of 1200 mAh. The positive electrode terminal was connected to the positive electrode sheet via an aluminium lead tab therebetween; and the negative electrode can was previously connected to the negative electrode sheet inside the battery, via a nickel lead tab therebetween.

[0110]
[Determination of Battery Characteristics]
[Determination of Cycle Property]
In a thermostat chamber kept at 25°C, the battery constructed according to the above-mentioned method was charged up to a terminal voltage of 3.6 V for 7 hours with a constant current and a constant voltage of 240 mAh (0.2 C), then this was discharged to a discharge voltage of 2.0 V under the constant current of 240 mAh (0.2 C), and the initial capacity of the battery was thus determined. The battery of which the initial capacity had been determined was further charged, in a thermostat chamber kept at
45°C, up to a terminal voltage of 3.6 V for 3 hours with a constant current and a constant voltage of 12 0 0 mAh (1 C), then this was discharged to a discharge voltage of 2.0 V under the constant current of 1200 mAh (1 C). This is one cycle. The battery was subjected to 100 cycles. After the cycle test, the capacity Retention of the battery was determined according to the following formula. As a result, the capacity retention of the battery was 83 %.
Capacity Retention (%)
= (discharge capacity after 100 cycles/discharge capacity in 1
cycle) X 100. [0111] Examples B-2 to B-7:
Like in Example B-1, LiPFg to be 0 . 95 M and LiN(S02CF3)2 to be 0.0 5 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) 18/10/2/35/3 5 (by volume), and in place of adding Compound-1

thereto, any of Compound-2 to Compound-7 was added thereto in an amount of 2 % by weight, thereby preparing a nonaqueous electrolytic solution in the same manner as in Example B-1. Using this, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table B-1. [0112] Comparative Example B-1:
Like in Example B-1, LiPFg to be 0 . 95 M and LiN(S02CF3)2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) 18/10/2/35/35 (by volume); however. Compound-1 was not added thereto. Using the thus-prepared nonaqueous electrolytic solution, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table B-1. [0113] Comparative Examples B-2 to 3:
Like in Example B-1, LiPFs to be 0.95 M and LiN(S02CF3)2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) 18/10/2/35/35 (by volume), and in place of adding Compound-1 thereto, any of Comparative Compound-1 or 2 was added thereto in an amount of 2 % by weight, thereby preparing a nonaqueous electrolytic solution in the same manner as in Example B-1. Using this, a cylindrical battery was constructed, and its battery characteristics were determined. The results are shown in Table

negative electrode, the electrolytic solution of the present invention is also effective for a silicon negative electrode, a tin negative electrode and an Li negative electrode, in enhancing the cycle property like in these Examples. [0116]
Example C-1: [Preparation of electrolytic solution]
LiPFs to be 0 . 95 M and LiNCSOaCFa) 2 to be 0 . 05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/methyl ethyl carbonate (MEC)/diethyl carbonate (DEC) = 8/20/2/35/35 (by volume) ,- and further, propargyl 2,4-difluorobenzoate was added thereto in an amount of 0.5 % by weight, thereby preparing a nonaqueous electrolytic solution. [0117] [Production of Lithium Ion Secondary Battery]
LiCo02 (positive electrode active material) (85 % by weight) , graphite (electroconductive agent) (10 % by weight) and polyvinylidene fluoride (binder) (5 % by weight) were mixed in that ratio, then a solvent of 1-methyl-2-pyrrolidone was added thereto and mixed. The resulting mixture was applied onto both surfaces of an aluminium foil (collector) , dried, processed under pressure and cut into a predetermined size, thereby producing a long rectangular, positive electrode sheet. Artificial graphite (negative electrode active material) (95 % by weight) and polyvinylidene fluoride (binder) (5 % by weight) were mixed in that ratio, and a solvent of 1-methyl-2-pyrrolidone was added thereto and mixed. The resulting mixture was applied onto both surfaces of a copper foil (collector), dried, processed under

pressure and cut into a predetermined size, thereby producing a long rectangular, negative electrode sheet. The positive electrode sheet, a porous polyethylene film separator, the negative electrode sheet and a separator were laminated in that order, and the resulting laminate was coiled up. The coil was housed into a nickel-plated, iron-made cylindrical battery can serving also as a negative electrode terminal. Further, the electrolytic solution was injected thereinto, and the can was calked with a battery cap having a positive electrode terminal, via a gasket therebetween, thereby constructing a 18650-type cylindrical battery. The positive electrode terminal was connected to the positive electrode sheet via an aluminium lead tab therebetween; and the negative electrode can was previously connected to the negative electrode sheet inside the battery, via a nickel lead tab therebetween. [0118]
[Determination of Battery Characteristics] [Determination of Cycle Property]
In a thermostat chamber kept at 25°C, the battery constructed according to the above-mentioned method was charged up to 4. 2 V with a constant current of 1 mA/cm^, and then further charged up to a terminal voltage of 4.35 V for 2.5 hours, and thereafter this was discharged to a discharge voltage of 3.0 V under a constant current of 0.33 mA/cm^, and the initial capacity of the battery was thus determined. The initial efficiency was 85 %.
Next, in a thermostat chamber kept at 6 0°C, the battery was charged up to 4.35 V with a constant current of 1 mA/cm^, then further charged at a constant voltage of 4.35 V for 2.5 hours, and thereafter discharged to a discharge voltage of 3.0 V under

a constant current of 1 mA/cm'. This is one cycle. The battery was subjected to 100 cycles. After the cycle test, the capacity retention of the battery was determined according to the following formula. As a result, the capacity retention of the battery after 100 cycles was 85 %. The results are shown in Table C-1. Capacity Retention (%) = (discharge capacity after IG-G
cycles/discharge capacity in 1 cycle) x 100. [0119] Examples C-2 to 11:
(Example C-6) , biphenyl
(Example C-7) , propargyl
(Example C-8) , propargyl
(Example C-9) , propargyl
LiPFs to be 0. 95 M and LiN(S02CF3) 2 to be 0. 05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/methyl ethyl carbonate (MEC)/diethyl carbonate (DEC) = 8/20/2/35/35 (by volume), and in place of adding propargyl 2,4-difluorobenzoate in Example C-1, propargyl 2-fluorobenzoate (Example C-2), propargyl 4-fluorobenzoate (Example C-3), allyl 2,4-difluorobenzoate (Example C-4), vinyl 2,4-difluorobenzoate (Example C-5), phenyl 2,4-difluorobenzoate 2,4-difluorobenzoate 2,6-difluorobenzoate 2,4,6-1ri fluorobenzoate 2,3,4,6-tetrafluorobenzoate (Example C-10), or propargyl pentaf luorobenzoate (Example C-11) was added thereto in an amount of 0.5 % by weight, thereby preparing a nonaqueous electrolytic solution. Using this, a 18650-type cylindrical battery was constructed, and the battery characteristics were determined in the same manner as in Example C-1. The results are shown in Table C-1. [0120]

Examples C-12 to 15:
LiPFg to be 0 . S5 M and LiN(S02CF3)2 to be 0 . 05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/methyl ethyl carbonate (MEC)/diethyl carbonate (DEC) = 8/20/2/35/35 (by volume); and propargyl 2,4-difluorobenzoate was added thereto in an amount of 0.01 % by weight (Example C-12), 2 % by weight (Example C-13), 5 % by weight (Example C-14), or 10 % by weight (Example C-15), thereby preparing a 18650-type cylindrical battery. In the same manner as in Example C-1, the battery characteristics were determined. The results are shown in Table C-1. [0121] Example C-16:
LiPFg to be 0.95 M and LiBF4 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/methyl ethyl carbonate (MEC)/diethyl carbonate (DEC) = 8/20/2/35/35 (by volume); and propargyl 2,4-difluorobenzoate was added thereto in an amount of 0 . 5 % by weight, thereby preparing a 18650-type cylindrical battery. In the same manner as in Example C-1, the battery characteristics were determined. The results are shown in Table C-1. [0122] Comparative Example C-1:
LiPFs to be 0 . 95 M and LiN(S02CF3) 2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/methyl ethyl carbonate (MEC)/diethyl carbonate (DEC) =8/20/2/35/35 (by volume), thereby preparing a nonaqueous electrolytic solution. Using this, a 18650-type cylindrical battery was constructed, and its battery

characteristics were determined in the same manner as in Example
C-1. The results are shown in Table C-1.
[0123] Comparative Examples C-2 to 5:
LiPFs to be 0 . 95 M and LiN(S02CF3) 2 to be 0. 05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/vinylene carbonate (VC)/methyl ethyl carbonate
(MEC)/diethyl carbonate (DEC) = 8/20/2/35/35 (by volume), and in place of adding thereto propargyl 2, 4-dif luorobenzoate in Example C-1, methyl 2,4-difluorobenzoate (Comparative Example C-2), methyl 2,6-difluorobenzoate (Comparative Example C-3), methyl 2-fluorobenzoate (Comparative Example C-4) , or methyl 4-fluorobenzoate (Comparative Example C-5) was added thereto in an amount of 0.5 % by weight, thereby preparing a nonaqueous electrolytic solution. Using this, a 18650-type cylindrical battery was constructed, and its battery characteristics were determined in the same manner as in Example C-1. The results are shown in Table C-1. [0124] [Table 4]

propargyl 2,4-dif luorobenzoate in an amount of 0.5 % by weight, adiponitrile in an amount of 1 % by weight and cyclohexyl sulfite in an amount of 0.5 % by weight were added thereto, thereby preparing a nonaqueous electrolytic solution and making a cylindrical battery in the same manner as in Example C-1. The battery characteristics were determined, and the results are shown in Table C-2. [0126] Comparative Example C-6:
Like in Example A-17, LiPFg to be 0. 95 M and LiN(S02CF3)2 to be 0.05 M were dissolved in a nonaqueous solvent of ethylene carbonate (EC)/propylene carbonate (PC)/fluoroethylene carbonate (FEC)/vinylene carbonate (VC)/methyl ethyl carbonate (MEG) = 3/20/5/2/70 (by volume); however, propargyl 2 , 4-dif luorobenzoate, adiponitrile and cyclohexyl sulfite were not added thereto. Using the thus-prepared nonaqueous electrolytic solution, a cylindrical battery was constructed in the same manner as in Example C-17, and its battery characteristics were determined. The results are shown in Table C-2. [0127] [Table 5] Table C-2

Composition of Electrolyte Salt
Composition of Nonaqueous
Electrolytic Solution Compound Amount
Added
(wt.%) Initial
Efficiency
(%) Capacity Retention after 100 cycles (%)
Example C-17 0.95M LiPFs + 0.05M UN(S02CF3)2
EC/PC/FECA/C/MEC(3/20/5/2/70)
+ adiponitrile (1 wt.%)
+ cyclohexyl sulfite (1 wt.%) propargyl 2,4-difluorobenzoate 0.5 93 86
Comparative Example C-6 0.95M LiPFs + 0.05M LiN(S02CF3)2 EC/PC/FECA/C/MEC(3/20/5/2/70) none - 54 47
[0128]

It is known that, as compared with the lithium secondary batteries of Comparative Examples not containing the specific compound represented by the general formula (III), the lithium secondary batteries of Examples C-1 to C-17 have more excellent battery performance in point of the initial battery capacity and the cycle property of the batteries.
Examples C-1 to C-17 of the present invention where the negative electrode is made of graphite confirm excellent cycle property; and not limited to the graphite negative electrode, the electrolytic solution of the present invention exhibits the same effects as in these Examples, for a silicon negative electrode, a tin negative electrode and an Li negative electrode, and also in a case where a lithium-containing olivine-type phosphate was used in the positive electrode. [Industrial Applicability] [0129]
According to the present invention, there are provided novel ester compounds useful as intermediate materials for medicines, agricultural chemicals, electronic materials, polymer materials and the like, or as battery materials.
The lithium secondary battery using the nonaqueous electrolytic solution of the present invention is excellent in the initial battery capacity and the cycle property thereof, and can maintain the battery performance for a long period of time.

Claims [Claim 1]
An ester compound represented by the following general formula (I) or (II): [Formula 1]

(wherein R1 represents a methoxy group or an ethoxy group; R1 represents a linear or branched alkenyl group having from 2 to 6 carbon atoms, a linear or branched alkynyl group having from
3 to 6 carbon atoms, a phenyl group or a biphenyl group) ,-
[Formula 2]

(wherein R1 represents a methoxy group or an ethoxy group; L1 represents a linear or branched alkylene group having from 2 to 6 carbon atoms, a linear or branched alkenylene group having from
4 to 6 carbon atoms, or a linear or branched alkynylene group having
from 4 to 6 carbon atoms).
[Claim 2]
The ester compound according to claim 1, wherein, in the general formula (I) , R1 is a methoxy group, and R1 is a vinyl group, an allyl group, a propargyl group, a phenyl group or a biphenyl group.
[Claim 3]

A nonaqueous electrolytic solution for lithium secondary-battery, comprising an electrolyte dissolved in a nonaqueous solvent and containing an ester compound represented by the following general formula (III) in an amount of from 0.01 to 10 % by weight of the nonaqueous electrolytic solution: [Formula 3]

(wherein R"11, R11, R1* and R11 each independently represent a hydrogen atom or a fluorine atom; R11 represents a hydrogen atom, a fluorine atom, a methoxy group or an ethoxy group; at least one of R1-"- to R""11 is a fluorine atom; iJ represents an alkyl group having from
1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an alkynyl group having from 3 to 6 carbon atoms, a phenyl group or a biphenyl group; provided that when all of R11 to R-""1 are fluorine atoms, then l7 represents an alkenyl group having from
2 to 6 carbon atoms, an alkynyl group having from 3 to 6 carbon atoms, a phenyl group or a biphenyl group).
[Claim 4]
The nonaqueous electrolytic solution for lithium secondary battery according to claim 3 , wherein, in the general formula (III) , L1 is a vinyl group, an allyl group or a propargyl group. [Claim 5]
The nonaqueous electrolytic solution for lithium secondary battery according to claim 3 or 4, wherein, in the general formula (III), at least two of R11, R11 and R11 are fluorine atoms. [Claim 6]

The nonaqueous electrolytic solution for lithium secondary-battery according to any of claims 3 to 5, wherein the electrolytic
solution contains at least two selected from ethylene carbonate, propylene carbonate, vinylene carbonate and fluoroethylene carbonate.
[Claim 7]
A nonaqueous electrolytic solution comprising an electrolyte salt dissolved in a nonaqueous solvent and containing an ester compound represented by the following general formula
(II) and/or (IV) in an amount of from 0.01 to 10 % by weight of the nonaqueous electrolytic solution:
[Formula 4]

(wherein R' represents a methoxy group or an ethoxy group; R1 represents a linear or branched alkyl group having from 1 to 6 carbon atoms, a linear or branched alkenyl group having from 2 to 6 carbon atoms, a linear or branched alkynyl group having from 3 to 6 carbon atoms, a phenyl group or a biphenyl group). [Claim 8]
The nonaqueous electrolytic solution according to claim 7,

wherein, in the general formula (IV) , R"1 is a methoxy group, and R1 is a methyl group, an ethyl group, a vinyl group, an allyl group, a propargyl group, a phenyl group or a biphenyl group. [Claim 9]
A lithium secondary battery comprising a positive electrode, a negative electrode and a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains at least one ester compound selected from those of general formulae (II), (III) and (IV) in an amount of from 0.01 to 10 % by weight of the nonaqueous electrolytic solution.