SPECIFICATION NONAQUEOUS ELECTROLYTE SOLUTION AND LITHIUM SECONDARY BATTERY USING SAME Technical Field [0001] The present invention relates to a nonaqueous electrolytic solution that can produce a lithium secondary battery exhibiting excellent long-term cycle property and storage property in a charged state, and to a lithium secondary battery using the nonaqueous electrolytic solution. Background Art [0002] In recent years, lithium secondary batteries have been widely used as driving power supplies for small electronic devices and the like. Such lithium secondary batteries are mainly constituted of a positive electrode comprised of a lithium compound oxide, a negative electrode comprised of a carbon material or a lithium metal, and a nonaqueous electrolytic solution. As the nonaqueous electrolytic solution, carbonates such as ethylene carbonate (EC) and propylene carbonate (PC) are used. A lithium secondary battery using, for example, LiCoOa, LiMn2O4 or LiNiO2 as a positive electrode material brings about a reduction of the battery performance, because the decomposition products inhibit the desired electrochemical reaction of the battery when part of the solvent of the nonaqueous electrolytic solution locally undergoes an oxidative decomposition during the charging. Such a reduction is considered to be attributed to an electrochemical oxidation of the solvent at the interface between the positive electrode material and the nonaqueous electrolytic solution. Also, a lithium secondary battery using, for example, a highly crystallized carbon material, such as natural graphite or artificial graphite, as a negative electrode material brings about a reduction of the battery performance, when the solvent of the nonaqueous electrolytic solution undergoes a reductive decomposition on the surface of the negative electrode during the charging. Even in the case of EC, which is widely used as a solvent for the nonaqueous electrolytic solution, it partly undergoes reductive decomposition during repeated charging and discharging cycles, resulting in reduction of the battery performance. [0003] Nonaqueous electrolytic solutions for improving the battery characteristics of such lithium secondary batteries are known, for example, in Patent Documents 1 to 3. Patent Document 1 discloses a battery using a nonaqueous electrolytic solution in which trifluoromethanesulfonate salts such as Sn(CF3SO3) 2 are dissolved to improve discharge property after the storage at high temperatures. However, this document does not describe problems of cycle property. Besides, the nonaqueous electrolytic solution in which Sn(CF3SO3)2 is dissolved is found to have a problem of unstable quality. for example due to deposits formed in the electrolytic solution during preservation for prolonged periods. Patent Document 2 discloses a nonaqueous electrolytic solution containing a specific tin salt. This document describes, for example, a battery using an electrolytic solution containing Sn(CF3SO3) 2, which exhibits improved charge and discharge efficiency at the initial stage, but does not describe a detailed mechanism regarding improvements in cycle property and storage property. Patent Document 3 discloses a nonaqueous electrolytic solution containing a specific organotin compound or a specific organogermanium compound. This document describes, for example, an electrolytic solution containing dibutyltin (1-allyloxymethyl)ethylene glycolate or dibutyltin bis (acetylacetonate) exhibiting improved cycle property after charging and discharging cycles at a charged voltage of 4.1 V. Unfortunately, electrolytic solutions containing these organotin compounds do not significantly improve cycle property at charging and discharging cycles up to 4.2 V, and lead to a significant reduction in electrical capacity during storage in the charged state of 4.2 V. As described above, a nonaqueous electrolytic solution containing a conventional organotin compound can improve battery characteristics to some extent but is still far from satisfaction. Nonaqueous electrolytic solutions and lithium secondary batteries with further improved long-term cycle property and storage property are needed. [0004] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2-37668 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2000-294274 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2003-173816 Disclosure of the Invention [0005] It is an object of the present invention to provide a nonaqueous electrolytic solution having excellent long-term cycle property and storage property in a charged state, and to provide a lithium secondary battery using the nonaqueous electrolytic solution. The inventors have found that a nonaqueous electrolytic solution containing a tin compound having a specific structure can exhibit high capacity, long-term cycle property, and storage property in a charged state, and have accomplished the present invention. Thus, the present invention provides the following aspects (1) and (3): (1) A nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, comprising 0.001% to 5% by weight of a tin compound represented by the following general formula (I) and/or (II), on the basis of the weight of the nonaqueous electrolytic solution: R1R2R3Sn-MR4R5R6 (I) where R1, R2, and R3 each represent a hydrogen atom, a halogen atom, a C1 to C12 alkyl group, a C2 to C12 alkenyl group, a C2 to C12 alkynyl group, a C6 to C18 aryl group, or a C6 to C18 aryloxy group that may be substituted; R4, R5, and R6 each represent a hydrogen atom, a halogen atom, a C1 to C12 alkyl group, a C2 to C12 alkenyl group, a C2 to C12 alkynyl group, or a C6 to C18 aryl group; M represents Si or Ge; and R1 to R3 and R4 to R6 may be the same or different from each other; and SnX2 (II) where X represents p-diketonate. (2) The nonaqueous electrolytic solution according to aspect (1), further comprising 0.001% to 5% by weight of a tin compound represented by the following general formula (III), on the basis of the weight of the nonaqueous electrolytic solution: where R7 represents a hydrogen atom, a C1 to C12 alkyl group, a C2 to C12 alkenyl group, a C2 to C12 alkynyl group, a C6 to C18 aryl group, or a C6 to CIS aryloxy group; R8, R9, and R10 each represent a Cl to C12 alkyl group, a C2 to C12 alkenyl group, a C2 to C12 alkynyl group, a C6 to C18 aryl group, or a C6 to C18 aryloxy group; and R8 to R10 may be the same or different from each other. (3) A lithium secondary battery comprising a positive electrode, a negative electrode, and a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution is the nonaqueous electrolytic solution of aspect (1) or (2). The lithium secondary battery using the nonaqueous electrolytic solution of the present invention can exhibit excellent electrical capacity, long-term cycle property, and storage property in a charged state• Detailed Description of the Invention [0006] The nonaqueous electrolytic solution of the present invention for lithium secondary batteries using a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, contains 0.001% to 5% by weight of a tin compound represented by the following general formula (I) and/or (II), on the basis of the weight of the nonaqueous electrolytic solution. The electrolytic solution containing such a tin compound exhibits excellent ionic conductivity to the film coated on the surface of the positive and/or negative electrodes, thereby inhibiting the decomposition of the solvent. As a result, secondary batteries using this electrolytic solution can exhibit excellent high capacity, long-term cycle property, and storage property in a charged state. [0007] One of the tin compounds used in the present invention is represented by the following general formula (I) : R1R2R3Sn-MR4R5R6 (I) where R1, R2 and R3 each represent a hydrogen atom, a halogen atom, a Cl to C12 alkyl group, a C2 to C12 alkenyl group, a C2 to C12 alkynyl group, a C6 to C18 aryl group, or a C6 to C18 aryloxy group that may be substituted; R4 R5, and R6 each represent a hydrogen atom, a halogen atom, a Cl to C12 alkyl group, a C2 to C12 alkenyl group, a C2 to C12 alkynyl group, or a C6 to C18 aryl group; M represents Si or Ge; and R1 to R2 and R3 to R6 may be the same or different from each other. [0008] group, R4 = methyl group, R5 = R6= phenyl group], trimethyl(dimethylethynylsilyl)tin [R1 = R2 = R3 = methyl group, R4 = R5 = methyl group, R6 = ethynyl group], triphenyl (dimethylethynylsilyl) tin [R1 = R2 = R3 = phenyl group, R4 = R5 = methyl group, R6 = ethynyl group] , chlorodimethyl (dimethylethynylsilyl) tin [R1 = R2 = methyl group, R3 = chlorine atom, R4 = R5 = methyl group, R6 = ethynyl group] , triphenyl (tert-butyldimethylsilyl) tin [R1 = R2 = R3 = phenyl group, R4 = R5 = methyl group, R6 = tert-butyl group] , triphenyl (octyldimethylsilyl) tin [R1 = R2 = R3 = phenyl group, R4 = R5 = methyl group, R6 = octyl group] , triphenyl (dimethylethynylsilyl) tin [R1 = R2 = R3 = phenyl group, R4 = R5 = methyl group, R6 = ethynyl group] , chlorodimethyl (dimethylethynylsilyl) tin [R1 = R2 = methyl group, R3 = chlorine atom, R4 = R5 = methyl group, R6 = ethynyl group], fluorodimethyl(dimethylethynylsilyl)tin [R1 = R2 = methyl group, R3 = fluorine atom, R4 = R5 = methyl group, R6 = ethynyl group], triphenyl(3-chloropropyldimethylsilyl)tin [R1 = R2 = R3 = phenyl group, R4 = R5 = methyl group, R6 = 3-chloropropyl group], trimethyl(3- bromopropyldiphenylsilyl) tin [R1 = R2 = R3 = methyl group, R4 = R5 = phenyl group, R6 = 3-bromopropyl group] , trimethyl (2-bromophenoxydiphenylsilyl) tin [R1 = R2 = R3 = methyl group, R4 = R5 = phenyl group, R6 = 2-bromophenoxy group] , methyldiphenyl (dimethylsilyl) tin [R1 = methyl, R2 = R3 = phenyl group, R4 = R5 = methyl group, R6 = hydrogen atom] , and tributyl (methyldiphenylsilyl) tin [R1 = R2= R3 = butyl group/ R4 = methyl group, R5 = R6 = phenyl group] . [0009] Among these preferred is at least one compound selected from the group consisting of tributyl(trimethylsilyl)tin, tributyl(triethylsilyl)tin, tributyl(tripropylsilyl)tin, tributyl(tributylsilyl)tin, triphenyl(trimethylsilyl)tin, triphenyl(dimethylallylsilyl)tin, triphenyl(dimethylphenylsilyl)tin, triphenyl (tert-butyldimethylsilyl)tin, triphenyl(dimethylethynylsilyl)tin, and chlorodimethyl(dimethylethynylsilyl)tin, from the viewpoint of improvements in long-term cycle property and storage property in a charged state. Among these particularly preferred is at least one compound selected from the group consisting of tributyl(trimethylsilyl)tin, triphenyl(dimethylallylsilyl)tin, and triphenyl(dimethylphenylsilyl)tin. [0010] trimethyl stannyl germane [R1 = R2 = R3 = methyl group, R4 = R5 = R6 = hydrogen atom], trimethyl(trimethylstannyl)germane [R1 = R2 = R3 = R4= R5 = R6 = methyl group], chlorodimethyl (trimethylstannyl) germane [R1 = R2 = R3 = methyl group, R4 = R5 = methyl group, R6 = chlorine atom], fluorodimethyl (trimethylstannyl) germane [R1 = R2 = R3 = methyl group, R4 = R5 = methyl group, R6 = fluorine atom], chlorodimethyl (chlorodimethylstannyl) germane [R1 = R2 = methyl group, R3 = chlorine atom, R4 = R5 = methyl group, R6 = chlorine atom], fluorodimethyl ( fluorodimethyl stannyl) germane [R1 = R^ = methyl group, R3 = fluorine atom, R4 = R5 = methyl group, R6 = fluorine atom], triethyl(trimethylstannyl)germane [R1 = R2 = R3 = methyl group, R4 = R5 = R6 = ethyl group], chlorobis (1-methylethyl) (trimethylstannyl) germane [R1 = R2 = R3 = methyl group, R4 = R4 = i-propyl group, R6 = chlorine atom], fluorobis(1- methylethyl) (trimethylstannyl) germane [R1 = R2 = R3 = methyl group, R4 = R5 = i-propyl group, R6 = fluorine atom], (dimethylphenylstannyl)methylphenyl-1-naphthalenylgermane [R1 = R2 = methyl group, R3 = phenyl group, R4 = methyl group, R5 = phenyl group, R6 = 1-naphthalenyl group], triphenyl(trimethylstannyl)germane [R1 = R2 = R3 = methyl group, R4 = R5 = R6 = phenyl group], [methyl (1-methylethyl) phenyl stannyl] triphenyl germane [R1 = methyl group, R2 = i-propyl group, R3 = R4 = R5 = R6 == phenyl group], [methyl(2-methyl-2- group, R4 = R5 = R6 = ethyl group], triphenyl (triphenylstannyl) germane [R1 = R2 = R3 = R4 = R5 = R6 = phenyl group], [ethylbis(phenylethynyl)stannyl]triphenylgermane [R1 = ethyl group, R2 = R3 = phenylethynyl group, R4 = R5 = R6 = phenyl group], [diethyl (phenylethynyl) stannyl] triphenylgermane [R1 = R2 = ethyl group, R3 = phenylethynyl group, R4 = R5 = R6 = phenyl group], [diphenyl (phenylethynyl) stannyl] triphenylgermane [R1 = R2 = phenyl group, R3 = phenylethynyl group, R4 = R5 = R6 = phenyl group], bis(pentafluorophenyl)(triethylstannyl)germane [R1 = R2 = pentafluorophenyl group, R3 = hydrogen atom, R4 = R5 = R6 = ethyl group], tris (pentaf luorophenyl) (triethylstannyl) germane [R = R2 = R3 = pentaf luorophenyl group, R4 = R5 = R6 = ethyl group] , trimethyl [tris (difluoromethyl) stannyl] germane [R1 = R2 = R3 = difluoromethyl group, R4 = R5 = R6 = methyl group], trimethyl[bis (difluoromethyl) (trifluoromethyl)stannyl] germane [R1 = R2 = difluoromethyl group, R3 = trif luoromethyl group, R4 = R5 = R6 = methyl group] , trimethyl[(difluoromethyl)bis(trifluoromethyl)stannyl]ger mane [R1 = di f luoromethyl group, R2 = R3 = trifluoromethyl group, R4 = R5 = R6 = methyl group], trimethyl[tris(trifluoromethyl)stannyl]germane [R1 = R2 = R3 = trifluoromethyl group, R4 = R5 = R6 = methyl group], Among these preferred is at least one compound selected from the group consisting of trimethyl(trimethylstannyl)germane, triethyl(trimethylstannyl)germane, trimethyl(triethylstannyl)germane, triethyl(triethylstannyl)germane, trimethyl(tripropylstannyl)germane, trimethyl(tributylstannyl)germane, triethyl(tributylstannyl)germane, tributyl(tributylstannyl)germane, trimethyl[tris(difluoromethyl)stannyl]germane, trimethyl[bis(difluoromethyl)(trifluoromethyl)stannyl]ger mane, trimethyl[(difluoromethyl)bis(trifluoromethyl)stannyl]ger mane, and trimethyl[tris(trifluoromethyl)stannyl]germane. from the viewpoint of improvements in long-term cycle property and storage property in a charged state. Among these particularly preferred is at least one compound selected from the group consisting of trimethyl(tributylstannyl)germane and triethyl(tributylstannyl)germane. [0012] The other of the tin compounds used in the present invention is represented by the following general formula (II) : SnX2 (II) where X represents p-diketonate. Specific examples of the tin compounds represented by the general formula (II) include bis(acetylacetonate)tin, bis(hexafluoroacetylacetonate)tin, bis(2,2,6, 6-tetramethyl-3,5-heptanedionate)tin, bis(2,2-dimethyl-3,5-hexanedionate)tin, bis(benzoylacetonate)tin, bis(methylacetylacetate)tin, bis(ethylacetylacetate)tin, bis(propylacetylacetate)tin, and bis(butylacetylacetate)tin. Among these preferred is at least one compound selected from the group consisting of bis (acetylacetonate)tin, bis(hexafluoroacetylacetonate)tin, from the viewpoint of improvements in long-term cycle property and sorage property in a charged state. [0013] group, R9 = R10 = phenyloxy group], tributylphenoxytin [R7 = R8 = R9 = butyl group, R10 = phenyloxy group] , dibutylbis (pentaf luorophenoxy) tin [R7= R8 = butyl, R9 = R10 = pentafluorophenyloxy group], and tributylpentaf luorophenoxytin [R'' = R^ = R^ = butyl group, R"^ ° = pentaf luorophenyloxy group] . [0015] Among the tin compounds represented by the general formula (III) preferred is at least one compound selected from the group consisting of tetrabutyltin, trimethylallyltin, tributylallyltin, tributylethynyltin, dibutyldivinyltin, triphenylallyltin, and tributylpentafluorophenoxytin, from the viewpoint of improvements in long-term cycle property and storage property in a charged state. [0016] In the present invention, an excessively large content of the tin compound in the nonaqueous electrolytic solution may impair battery characteristics, whereas a significantly small content of the tin compound in the nonaqueous electrolytic solution may not enhance the effect of improvements in long-term cycle property and storage property in a charged state. Therefore, the content of the tin compound represented by the general formula (I) or (III) is preferably 0.001% by weight or more, more preferably 0.1% by weight or more, and most preferably 0.2% by weight or more, on the basis of the weight of the nonaqueous electrolytic solution. Also, the content of the tin compound represented by the general formula (I) or (III) is preferably 5% by weight or lower, more preferably 1% by weight or lower, and most preferably 0,5% by weight or lower, on the basis of the weight of the nonaqueous electrolytic solution. The content of the tin compound represented by the general formula (II) is preferably 0.001% by weight or more, more preferably 0.02% by weight or more, and most preferably 0.05% by weight or more, on the basis of the weight of the nonaqueous electrolytic solution. Also, the content of the tin compound represented by the general formula (II) is preferably 5% by weight or lower, more preferably 0.5% by weight or lower, and most preferably 0.2% by weight or lower, on the basis of the weight of the nonaqueous electrolytic solution. In the case of a mixture of a tin compound represented by the general formula (II) and a tin compound represented by the general formula (I) or (III), it is preferred that the content of the tin compound represented by the general formula (II) is lower than that of the tin compound represented by the general formula (I) or (III) . This is because a surface film of the tin compound represented by the general formula (II) is more rapidly formed on a negative electrode than that of the tin compound represented by the general formula (I) or (III). Thus, a larger amount of the tin compound represented by the general formula (II) than the tin compound represented by the general formula (I) or (III) may offset the effect of mixing. [0017] Examples of nonaqueous solvents used in the present invention include cyclic carbonates, linear carbonates, sulfur acid ester compounds, esters, ethers, amides, phosphate esters, sulfones, lactones, and nitriles. Examples of the cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, fluoroethylene carbonate, and vinylethylene carbonate. In particular, EC, which has a high dielectric constant, is most preferred. Examples of the linear carbonates include asymmetric carbonates such as methyl ethyl carbonate (MEC), methyl propyl carbonate, methyl butyl carbonate, and ethyl propyl carbonate; and symmetric carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), and dipropyl carbonate. In particular, DEC, which exhibits excellent storage property in a charged state and cycle property at high temperatures, is most preferred. [0018] Examples of the sulfur acid ester compounds include 1,3-propane sultone (PS), 1,4-butanediol dimethanesulfonate, glycol sulfite, propylene sulfite, glycol sulfate, and propylene sulfate. Examples of the esters include methyl propionate, methyl pivalate, butyl pivalate, hexyl pivalate, octyl pivalate, dimethyl oxalate, ethyl methyl oxalate, and diethyl oxalate. Examples of the ethers include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1/2-diethoxyethane, and 1,2-dibutoxyethane. Examples of the amides include dimethylformamide. Examples of the phosphate esters include trimethyl phosphate and trioctyl phosphate. Examples of the sulfones include divinylsulfone. Examples of the lactones include y-butyrolactone, y-valerolactone, and a-angelicalactone. Examples of the nitriles include acetonitrile and adiponitrile. [0019] Among these nonaqueous solvents preferred are cyclic carbonates, linear carbonates, esters, and sulfur acid ester compounds. These compounds may be used alone or in combination. More preferably, the nonaqueous solvent contains a cyclic carbonate and/or a linear carbonate. In particular, combinations of cyclic carbonates, such as EC and PC, and linear carbonates, such as MEC and DEC, are most preferred. The volume ratio of the cyclic carbonate to the linear carbonate ranges from 10:90 to 40:60, more preferably from 20:80 to 40:60, and most preferably from 25:75 to 45:55. [0020] A combined use of a cyclic carbonate and a linear carbonate with vinylene carbonate (VC) and/or a sulfur acid ester compound is preferred in order to improve storage property in a charged state. Preferred sulfur acid ester compounds are at least one compound selected from the group consisting of 1,3-propane sultone (PS), glycol sulfite, 1,4-butanediol dimethanesulfonate. Particularly preferred is 1,3-propane sultone (PS). The content of vinylene carbonate and/or the sulfur acid ester compound desirably ranges from 0.01% to 10% by volume, preferably from 0.02% to 9% by volume, more preferably from 0.03% to 8% by volume, and most preferably from 0.05% to 5% by volume, on the basis of the content of the nonaqueous solvent. [0021] Examples of electrolyte salts used in the present invention include lithium salts such as LiPFe, LiBF4, and LiC1O4; alkyl-containing lithium salts such as LiN(SO2CF3) 2, LiN(SO2C2F5)2/ LiC(SO2CF3)3, LiPF4(CF3)2, LiPF3 (C2F5) 3, LiPF3(CF3)3, LiPFs (iso-C3F7) 3, and LiPFs (ISO-C3F7) ; and cycloalkylene-containing lithium salts such as (CF2) 2 (SO2)2NLi and (CF2)3 (SO2) 2NLi. Among these particularly preferred electrolyte salts are LiPFe, LiBF4, and LiN (SO2CF3) 2. The most preferred electrolyte salt is LiPFe. These electrolyte salts may be used alone or in combination. Examples of preferred combinations of these electrolyte salts include a combination of LiPFe and LiBF4, a combination of LiPFe and LiN (SO2CF3) 2/ and a combination of LiBF4 and LiN (SO2CF3) 2. Particularly preferred is a combination of LiPFe and LiBF4. The electrolyte salts can be mixed at any ratio. In the case of a combined use of any other electrolyte salt with LiPFe, a proportion (molar ratio) of the other electrolyte salt desirably ranges from 0.01% to 45%, preferably from 0.03% to 20%, more preferably from 0.05% to 10%, and most preferably from 0.05% to 5%, The concentration of the total amount of these electrolyte salts generally ranges from 0.1 to 3 M, preferably from 0.5 to 2.5 M, more preferably from 0.7 to 2.0 M, and most preferably from 0.8 to 1.4 M, on the basis of the amount of the nonaqueous solvent. [0022] Examples of preferred combinations of the nonaqueous solvents and the electrolyte salts include solutions containing a mixed solvent of EC and/or PC and MEC and/or DEC in which LiPFe and/or LiBF4 is dissolved as an electrolyte salt. The nonaqueous electrolytic solution of the present invention may be prepared, for example, by mixing nonaqueous solvents such as EC, PC, MEC, DEC, VC, and PS, dissolving an electrolyte salt therein, and further dissolving a tin compound represented by the general formula (I) and/or (II) and a tin compound represented by the general formula (III) . It is preferred that the nonaqueous solvents, the tin compounds represented by the general formulae (I) to (III), and other additives used are preliminarily purified to reduce impurities as much as possible within the scope not causing significant decrease of productivity. [0023] Incorporation of, for example, air or carbon dioxide in the nonaqueous electrolytic solution of the present invention can prevent gas generation due to decomposition of the electrolytic solution and can improve battery characteristics such as long-term cycle property and storage property in a charged state. In the present invention, methods for incorporating (dissolving) air or carbon dioxide in the nonaqueous electrolytic solution include (1) bringing the nonaqueous electrolytic solution into contact with air or carbon dioxide-containing gas before the solution is fed into a battery; or (2) feeding the solution into a battery and then incorporating air or carbon dioxide-containing gas in the solution before or after the battery is sealed. It is preferred that the air or carbon dioxide-containing gas contain moisture as little as possible and have a dew point of -40°C or below, and more preferably -50°C or below. In the present invention, use of a nonaqueous electrolytic solution containing dissolved carbon dioxide is particularly preferred in order to improve storage property in a charged state at high temperatures. The amount of dissolved carbon dioxide is desirably 0.001% by weight or more, preferably 0.05% by weight or more, and more preferably 0.2% by weight or more. A nonaqueous electrolytic solution containing saturated carbon dioxide is most preferred. [0024] The nonaqueous electrolytic solution of the present invention may further contain an aromatic compound to enhance the safety of overcharged batteries. Examples of such aromatic compounds include the following groups (a) to (c): (a) Cyclohexylbenzene, fluorocyclohexylbenzene compounds (1-fluoro-2-cyclohexylbenzene, l-fluoro-3-cyclohexylbenzene, and 1-fluoro-4-cyclohexylbenzene), and biphenyl; (b) tert-Butylbenzene, 1-fluoro-4-tert-butylbenzene, tert-amylbenzene, 4-tert-butylbiphenyl, 4-tert-amylbiphenyl, and 1,3-di-tert-butylbenzene; (c) Terphenyls (o-, m- and p-), diphenyl ether, 2- fluorodiphenyl ether, 4-diphenyl ether, fluorobenzene, difluorobenzenes (o-, m- and p-), 2-fluorobiphenyl, 4-fluorobiphenyl, 2,4-difluoroanisole, and partially hydrogenated terphenyls (1,2-dicyclohexylbenzene, 2-phenylbicyclohexyl, 1,2-diphenylcyclohexane, and o-cyclohexylbiphenyl). Among these, groups (a) and (b) are preferred. Most preferred is at least one compound selected from the group consisting of cyclohexylbenzene, fluorocyclohexylbenzene compounds (l-fluoro-4-cyclohexylbenzene and the like), tert-butylbenzene, tert-amylbenzene, and 1,3-di-tert-butylbenzene. A total content of the aromatic compounds preferably ranges from 0.1% to 5% by weight. [0025] The lithium secondary battery of the present invention comprises a positive electrode, a negative electrode, and a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent. These components, such as a positive electrode and a negative electrode, other than the nonaqueous electrolytic solution can be used without limitation. For example, usable positive electrode active materials include complex metal oxides of lithium with cobalt, manganese, or nickel. Such positive electrode active materials may be used singly or in combination of two or more thereof. Examples of such lithium-containing complex metal oxides include LiCoO2/ LiMn2O4, LiNiO2/ LiCoi-xNixO2 (0.01