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Non Aqueous Electrolytic Solution, And Lithium Battery Comprsiing Same

Abstract: Provided are a nonaqueous electrolytic solution including an electrolyte salt dissolved in a nonaqueous solvent, which is characterized by containing a fluorine-containing phenol represented by the following general formula (I) in an amount of from 0.01 to 3% by mass of the nonaqueous electrolytic solution, and is excellent in storage property of a primary battery, cycle property upon use of a secondary battery at a high temperature, and suppressing effect on the generation of a gas during the charged battery storing of the secondary battery, and a lithium battery using the solution. (In the formula, X1 to X5 each independently represent a fluorine atom or a hydrogen atom, and 3 to 5 thereof represent fluorine atoms).

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Patent Information

Application #
Filing Date
23 May 2011
Publication Number
36/2012
Publication Type
INA
Invention Field
ELECTRICAL
Status
Email
Parent Application

Applicants

UBE INDUSTRIES, LTD.
1978-96, OAZA KOGUSHI, UBE-SHI, YAMAGUCHI 755-8633

Inventors

1. ABE, KOJI
C/O UBE INDUSTRIES, LTD., 1978-96, OAZA KOGUSHI, UBE-SHI, YAMAGUCHI - 7558633

Specification

Specification [Title of the Invention] NON-AQUEOUS ELECTROLYTIC SOLUTION, AND LITHIUM BATTERY COMPRISING SAME [Technical Field] [1] The present invention relates to a nonaqueous electrolytic solution and a lithium battery using the same. [Background Art] [2] In recent years, a lithium secondary battery has been widely used as a drive power supply for small-size electronic devices such as mobile telephones, notebook-size personal computers and the like, and a power supply for electric vehicles as well as for electric power storage. The lithium secondary battery is 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. For the nonaqueous electrolytic solution, used are carbonates such as ethylene carbonate (EC), propylene carbonate (PC), etc. As the negative electrode of the lithium secondary battery, known are metal lithium, and metal compounds (metal elemental substances, oxides, alloys with lithium, etc.) and carbon materials capable of absorbing and releasing lithium. In particular, a nonaqueous electrolytic solution secondary battery using, among carbon materials, a carbon material capable of absorbing and releasing lithium such as coke, graphite (such as artificial graphite or natural graphite) or the like has been widely put into practical use. Since any such negative electrode material as described above stores and releases lithium and an electron at a low potential similar to that of a lithium metal, the material has the possibility that a large number of solvents undergo reductive decomposition particularly under high temperatures. In addition, irrespective of the kind of the negative electrode material, part of a solvent in the electrolytic solution undergoes reductive decomposition on a negative electrode, and the decomposed product deposits on the surface of the negative electrode to increase the resistance of the electrode. Alternatively, a gas is generated owing to the decomposition of the solvent to swell the battery. Accordingly such solvents decomposition hinders the movement of a lithium ion, thereby causing such a problem that battery characteristics such as high-temperature cycle property worsen. [3] On the other hand, a material capable of absorbing and releasing lithium such as LiCoO2, LiMn2O4, LiNiO2, or LiFePO4 to be used as a positive electrode material has the possibility that a large number of solvents undergo oxidative decomposition because the material stores and releases lithium and an electron at a high voltage of 3.5 V or more with reference to lithium. In addition, irrespective of the kind of the positive electrode material, part of the solvent in the electrolytic solution undergoes oxidative decomposition on a positive electrode, and the decomposed product deposits on the surface of the positive electrode to increase the resistance of the electrode. Alternatively, a gas is generated owing to the decomposition of the solvent to swell the battery. Accordingly such solvents decomposition hinders the movement of a lithium ion, thereby causing such a problem that the battery characteristics such as the high-temperature cycle property worsen. [4] Patent Reference 1 discloses a nonaqueous electrolyte battery containing, in an electrolyte, such a compound that a first-stage pKa value in an aqueous solution of the compound itself or a conjugate acid thereof is 8.0 or more (e.g., phenol, o-fluorophenol, m-fluorophenol, or p-fluorophenol) . The reference describes that in the battery, the electrolyte becomes additionally basic to prevent a positive electrode active material such as lithium nickelate, lithium cobaltate, or spinel-phase lithium manganate as a basic oxide from becoming instable against an acid, thereby exerting an improving effect on lifetime property. Patent Reference 2 discloses a nonaqueous electrolytic solution battery obtained by adding, to a nonaqueous electrolytic solution, an organic compound having a reversible oxidation-reduction potential at a more electropositive battery potential than a positive electrode potential during full charge such as 2,4-difluorophenol. The reference describes the following. Even when the battery is brought into an overcharged state, an overcharge reaction on an electrode is inhibited/ and an increase in the temperature of the battery stops simultaneously with the cut-off of an overcharge current. Accordingly, the battery does not generate heat. [5] Besides, as a lithium primary battery, for example, there is known a lithium primary battery including manganese dioxide or graphite fluoride as the positive electrode and a lithium metal as the negative electrode, and the lithium primary battery is widely used as having a high energy density. It is desired to inhibit the self-discharge and increase in the internal resistance of the battery during high-temperature storage and to improve the storage property thereof. Recently, further, as a novel power source for electric vehicles or hybrid electric vehicles, electric storage devices have been developed, for example, a so-called electric double layer capacitor using activated carbon or the like as the electrode from the viewpoint of the output density thereof, and a so-called hybrid capacitor including a combination of the electric storage principle of a lithium ion secondary battery and that of an electric double layer capacitor (an asymmetric capacitor where both the capacity by lithium absorption and release and the electric double layer capacity are utilized) from the viewpoint of both the energy density and the output density thereof; and it is desired to improve the cycle property and the like at high temperatures of these capacitors. [6] [Patent Reference 1] JP 2000-156245 A [Patent Reference 2] JP 2000-156243 A [Disclosure of the Invention] [Problems that the Invention is to Solve] [7] An object of the present invention is to provide a nonaqueous electrolytic solution excellent in storage property of a primary battery, cycle property upon use of a secondary battery at a high temperature, and suppressing effect on the generation of a gas during the charged secondary battery is charged or stored, and a lithium battery using the solution. [Means for Solving the Problems] [8] The inventors of the present invention have-made detailed investigations on the performance of each of the nonaqueous electrolytic solutions of the above-mentioned prior art. As a result, none of Patent References 1 and 2 described above pays attention to the generation of a gas during charged battery storing at a high temperature and to high-temperature cycle property. Reproductive experiments of the examples of those references have elucidated that the nonaqueous electrolytic solutions have nearly no suppressing effect on the generation of a gas during battery charging or storing at a high temperature, and hence the high-temperature cycle property worsen. In view of the foregoing, the inventors of the present invention have made extensive studies to solve the above-mentioned problems. As a result, the inventors have found that the addition of a small amount of phenol 3 to 5 hydrogen atoms of which are substituted with fluorine suppresses the generation of a gas during charged battery storing at a high temperature, and hence the high-temperature cycle property can be improved. Further, the inventors have understood that those effects correlate with the pKa value of each compound, and in particular, have found that a compound having a pKa value of from 5 to 7 shows excellent properties. Thus, the inventors have completed the present invention. [9] That is, the present invention provides the following items (1) and (2). (1) A nonaqueous electrolytic solution comprising an electrolyte salt dissolved in a nonaqueous solvent, which comprises a fluorine-containing phenol represented by the following general formula (I) in an amount of from 0.01 to 3% by mass of the nonaqueous electrolytic solution: [10] wherein X1 to X5 each independently represent a fluorine atom or a hydrogen atom, and 3 to 5 thereof represent fluorine atoms. [11] (2) Alithiumbattery, comprising: a positive electrode; a negative electrode; and a nonaqueous electrolytic solution prepared by dissolving an electrolyte salt in a nonaqueous solvent, wherein the nonaqueous electrolytic solution comprises the fluorine-containing phenol represented by the general formula (I) in an amount of from 0.01 to 3% by mass of the nonaqueous electrolytic solution. [Advantage of the Invention] [12] According to the present invention, there can be provided a nonaqueous electrolytic solution excellent in storage property of a primary battery, cycle property upon use of a secondary battery at a high temperature, and suppressing effect on the generation of a gas when the charged secondary battery is stored, and a lithium battery using the solution. [Best Mode for Carrying out the Invention] [13] [Nonaqueous Electrolytic Solution] A nonaqueous electrolytic solution of the present invention is a nonaqueous electrolytic solution including an electrolyte salt dissolved in a nonaqueous solvent, and is characterized by containing a fluorine-containing phenol represented by the general formula (I) in an amount of from 0.01 to 3% by mass of the nonaqueous electrolytic solution. [14] [Fluorine-containing phenol represented by general formula (I)] The fluorine-containing phenol in the nonaqueous electrolytic solution of the present invention is represented by the following general formula (I). [15] [16] In the general formula (I), X1 to X5 each independently represent a fluorine atom or a hydrogen atom, and 3 to 5 thereof represent fluorine atoms. That is, the fluorine-containing phenol represented by the general formula (I) is one ormore kinds selected fromtrifluorophenol, tetrafluorophenol, and pentafluorophenol. Specific examples thereof include 2,3,4-trifluorophenol, 2,3,5-trifluorophenol, 2,3,6-trifluorophenol, 2, 4, 5-trifluorophenol, 2,4,6-trifluorophenol, 3,4,5-trifluorophenol, 2,3,5,6-tetrafluorophenol, and pentafluorophenol. Of those, preferred is one having a fluorine atom at an ortho-position and/or the para-position relative to the hydroxyl group in the general formula (I), and more preferred is one having a fluorine atom at the para-position. Of the fluorine-containing phenol represented by the general formula (I), more preferred are tetrafluorophenol and pentafluorophenol, even more preferred are 2, 3,5,6-tetrafluorophenol and pentafluorophenol, particularly preferred is pentafluorophenol. [17] The above-mentioned specific compounds are preferred because the compounds each have high high-temperature cycle property and a high suppressing effect on the generation of a gas during charged battery storing. Although reasons for the foregoing are not necessarily clear, the property and the effect are considered to result from the following reasons. It has bean elucidated that when a battery is stored under a high temperature in a charged state, a basic impurity such as LiOH present in a trace amount in a positive electrode serves as a catalyst to help the decomposition of a nonaqueous solvent such as a cyclic carbonate or a linear carbonate, and hence a CO2 gas or the like is generated. As shown in Table 1, pentafluorophenol and the like belonging to the fluorine-containing phenol represented by the general formula (I) are acidic compounds having pKa values in a specific range, and the addition of a small amount of the fluorine-containing phenol may result in the formation of a stable surface film through a reaction with LiOH as the impurity present on the surface of the positive electrode. As a result, it may become possible to suppress the generation of a gas during charged battery storing at a high temperature. In addition, the fluorine-containing phenol is not a strong acid, and is hence nearly free of such an influence that a metal element in a positive electrode active material is eluted. Accordingly, the positive electrode active material does not deteriorate. Further, the fluorine-containing phenol shows excellent high-temperature cycle property probably because of the following reason. The fluorine-containing phenol can decompose on a negative electrode to form a fluorine-containing surface film, and hence the decomposition of the nonaqueous solvent on the negative electrode can be suppressed. [18] [Table 1] Table l [19] Here, the pKa value is also called an acid dissociation constant, and the pKa can be measured by an ordinary method. For example, the pKa can be determined in accordance with the method described in Experimental Chemistry Seminar 5 "Thermal Measurement and Equilibrium", p. 460 (edited by the Chemical Society of Japan, published by Maruzen Company, Limited.). The pKa value of the fluorine-containing phenol is preferably from 5 to 7, more preferably from 5 to 6.5, and still more preferably from 5.3 to 5.7 from the viewpoints of high-temperature cycleproperty and the suppression of the generation of a gas during charged battery Storing. [20] [Content of fluorine-containing phenol] In the nonaqueous electrolytic solution of the present invention, when the content of the fluorine-containing phenol represented the general formula (I) in the nonaqueous electrolytic solution exceeds 3% by mass, a surface film is excessively formed on an electrode, and hence battery characteristics such as high-temperature cycle property may worsen. In addition, when the content is less than 0.01% by mass, a protecting effect on a positive electrode or a negative electrode is not sufficient, and hence the high-temperature cycle property or a suppressing effect on the generation of a gas during charged battery storing cannot be obtained in some cases. Therefore, the content of the compound in the nonaqueous electrolytic solution is 0. 01% by mass or more, preferably 0.03% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. In addition, an upper limit for the content is 3% by mass or less, preferably 2% by mass or less, more preferably 1.5% by mass. or less, and still more preferably 0.5% by mass or less. When two or more kinds of the fluorine-containing phenols are used in combination, the total content of the phenols preferably falls within the above-mentioned range. [21] In the nonaqueous electrolytic solution of the present invention, the high-temperature cycle property and the suppressing effect on the generation of a gas during charged battery storing are improved even when the fluorine-containing phenol represented by the general formula (I) in the nonaqueous electrolytic solution is used alone. However, when combined with a nonaqueous solvent, an electrolyte salt, and furthermore, any other additive to be described later, the fluorine-containing phenol exerts such a specific effect that the high-temperature cycle property and the suppressing effect on the generation of a gas during charged battery storing are synergistically improved. Although a reason for the foregoing is not necessarily clear, the specific effect is exerted probably because a mixed surface film containing the fluorine-containing phenol and constitutive elements of the nonaqueous solvent, the electrolyte salt, and furthermore, the other additive, and having high ionic conductivity is formed. [0022] [22] [Nonaqueous Solvent] The nonaqueous solvent for use in the nonaqueous electrolytic solution of the present invention includes cyclic carbonates, linear carbonates, linear esters, ethers, amides, phosphates, sulfones, lactones, nitriles, S=O bond-containing compounds, aromatic compounds, etc. The cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), 4-fluoro-l,3-dioxolan-2-one (FEC), trans or cis-4, 5-difluoro-l,3-dioxolan-2-one (hereinafter, the two are collectively referred to as "DFEC"), vinylene carbonate (VC), vinylethylene carbonate (VEC), etc. Of those, from the viewpoints of the high-temperature cycle property and the suppression of the generation of a gas during charged battery storing, one or more kinds selected from EC, PC, and a cyclic carbonate containing a carbon-carbon double bond or fluorine are preferred, and the nonaqueous electrolytic solution particularly preferably contains EC and/or PC, and both of a cyclic carbonate containing a carbon-carbon double bond and a cyclic carbonate containing fluorine. As the carbon-carbon double bond-containing cyclic carbonate, preferred are VC and VEC; and as the fluorine-containing cyclic carbonate, preferred are FEC and DFEC. [23] One kind of those solvents may be used, but using two or more different kinds as combined is preferred as further improving the high-temperature cycle property or the suppressing effect on the generation of a gas during charged battery storing. Even more preferably/ three or more different kinds are combined. Preferred combinations of the cyclic carbonates include EC and PC; EC and VC; EC and VEC; PC and VC; FEC and VC; FEC and EC; FEC and PC; FEC and DFEC; DFEC and EC; DFEC and PC; DFEC and VC; DFEC and VEC; EC and PC and VC; EC and FEC and PC; EC and FEC and VC; EC and VC and VEC; FEC and PC and VC; DFEC and EC and VC; DFEC and PC and VC; FEC and EC and PC and VC; DFEC and EC and PC and VC, etc. Of those combinations, more preferred combinations are EC and VC; FEC and PC; DFEC and PC; EC and FEC and PC; EC and FEC and VC; EC and PC and VC; and EC and VC and VEC, etc. Not specifically defined, the content of the cyclic carbonate is preferably within a range of from 10 to 40% by volume relative to the total volume of the nonaqueous solvent. When the content is less than 10% by volume, then the electric conductivity of the electrolytic solution may lower, and the internal resistance of the battery may increase, but when more than 40% by volume, then the high-temperature cycle property or the suppressing effect on the generation of a gas during charged battery storing may worsen. [24] 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.; symmetric linear carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, dibutyl carbonate, etc. In particular, the nonaqueous electrolytic solution preferably contains the symmetric linear carbonate because the high-temperature cycle property and the suppressing effect on the generation of a gas during charged battery storing tend to be improved, and the symmetric linear carbonate and the asymmetric linear carbonate are more preferably used in combination. The symmetric linear carbonate is particularly preferably diethyl carbonate (DEC). Although one kind of those linear carbonates may be used, two or more kinds of them are preferably used in combination because the above-mentioned effects are additionally improved. Not specifically defined, the content of the linear carbonate is preferably within a range of from 60 to 90% by volume relative to the total volume of the nonaqueous solvent. When the content is less than 60% by volume, then the viscosity of the electrolytic solution may increase; but when more than 90% by volume, then the electric conductivity of the electrolytic solution may lower and battery characteristics such as the high-temperature cycle property may worsen. Accordingly, the above range is preferred. A ratio (volume ratio) "cyclic carbonates: linear carbonates" between the cyclic carbonates and the linear carbonates is preferably from 10:90 to 40:60, more preferably from 15:85 to 35:65, and particularly preferably from 20:80 to 30:70 from the viewpoints of the improvements of the high-temperature cycle property and the suppressing effect on the generation of a gas during charged battery storing. [25] The linear esters include methyl propionate, ethyl propionate, methyl acetate, ethyl acetate, methyl pivalate, butyl pivalate, hexyl pivalate/ octyl pivalate, dimethyl oxalate, ethyl methyl oxalate, diethyl oxalate, etc. The ethers include cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, etc.; linear ethers such as 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 sulfolane, etc.; the lactones include γ-butyrolactone, γ-valerolactone, α-angelicalactone, etc.; the nitriles include acetonitrile, propionitrile, succinonitrile, glutaronitrile, adiponitrile, etc. Examples of the S=0 bond-containing compound include: sultone compounds such as 1,3-propanesultone(PS), 1,3-butanesultone, and 1,4-butanesultone; cyclic sulfite compounds such as ethylene sulfite, hexahydrobenzo[1, 3,2Jdioxathiolane-2-oxide (also referred to as 1.2- cyclohexanediol cyclic sulfite), and 5-vinyl-hexahydro-l, 3,2-benzodioxathiol-2-oxide; disulfonic acid diester compounds such as 1,4-butanediol dimethanesulfonate and 1.3- butanediol dimethanesulfonate; and vinyl sulfone compounds such as divinyl sulfone, 1,2-bis(vinylsulfonyl)ethane, and bis(2-vinylsulfonylethyl) ether. [26] Examples of the aromatic compounds include aromatic compounds each having a branched alkyl group, such as cyclohexylbenzene, fluorocyclohexylbenzene compounds (including l-fluoro-2-cyclohexylbenzene, l-fluoro-3-cyclohexylbenzene, and l-fluoro-4-cyclohexylbenzene), tert-butylbenzene, tert-amylbenzene, l-fluoro-4-tert-butylbenzene, and 1,3-di-tert-butylbenzene, and aromatic compounds such as biphenyl, terphenyls (o-, m-, and p-isomers), diphenyl ether, fluorobenzene, difluorobenzene (o-, m-, and p-isomers), 2,4-difluoroanisole, and partially hydrogenated terphenyl (inlcuding 1,2-dicyclohexylbenzene, 2-phenylbicyclohexyl, 1,2-diphenylcyclohexane, and o-cyclohexylbiphenyl). [27] The fluorine-containing phenol represented by the general formula (I) is preferably used in combination with one or more kinds selected from, in particular, the cyclic ethers, the S"0 bond-containing compounds, and the aromatic compounds each having a branched alkyl group out of the above-mentioned nonaqueous solvents because the high-temperature cycle property and the suppressing effect on the generation of a gas during charged battery storing are improved. Of those, an S=0 bond-containing compound is particularly preferred. When the addition amount of any such compound to be used in combination with the fluorine—containing phenol represented by the general formula (I) exceeds 5% by mass, the high-temperature cycle property may worsen. In addition, when the addition amount is less than 0.05% by mass, an improving effect on the property cannot be sufficiently obtained in some cases. Accordingly, the content is preferably at least 0.05% by mass of the mass of the nonaqueous electrolytic solution, more preferably at least 0.5% by mass. The upper limit of the content is preferably at most 5% by mass, more preferably at most 3% by mass. [28] In general, the nonaqueous solvents are used as a mixture thereof for attaining the suitable physical properties. Regarding their combinations, for example, there are mentioned combinations of cyclic carbonates alone, combinations of linear carbonates alone, a combination of a cyclic carbonate and a linear carbonate, a combination of a cyclic carbonate, a linear carbonate, and a lactone, a combination of a cyclic carbonate, a linear carbonate, and a linear ester, a combination of a cyclic carbonate, a linear carbonate, and a ether, a combination of a cyclic carbonate, a linear carbonate, and an S»0 bond-containing compound, etc. Of those, preferred is using a nonaqueous solvent of a combination of at least a cyclic carbonate and a linear carbonate, as improving the high-temperature cycle property or the suppressing effect on the generation of a gas during charged battery storing. More specifically, a combination of one or more kinds of cyclic carbonates selected from EC, PC, VC, VEC, and FEC, and one or more kinds of linear carbonates selected from DMC, MEC, and DEC is given. [29] [Electrolyte Salt] The electrolyte salt for use in the present invention includes lithium salts such as LiPF6, LiBF4, LiClO4, etc.; linear fluoroalkyl group-containing lithium salts such as LiN(SO2CF3)*, LiN (SO2C2F5) 2, LiCF3SO3/ LiC (S02CF3) 3, LiPF4(CF3)2, LiPF3 (C2FS) 3, LiPF3(CF3)3, LiPF3(iso-CaF?)n LiPF5 (iso-C3F7), etc.; cyclic fluoroalkylene chain-containing lithium salts such as (CF2) % (SO2) aNLi, (CFz) 3 (SO2) NLi, etc.; and lithium salts with an anion of an oxalate complex such as lithium bis[oxalate-0,0'Jborate, lithium difluoro [oxalate-0,01 ]borate, etc. Of those, especiallypreferred electrolyte salts are LiPF6, LiBFa, LiN (S0aCF3) 2, and LiN{S02C2F5)2. Of those, most preferred electrolyte salts are LiPFs, LiBF4, and LiN (SO2CF3) 2- One or more of these electrolyte salts may be used herein either singly or as combined. [30] A preferred combination of these electrolyte salts is a combination containing LiPF6 and further containing a lithium salt that contains a nitrogen atom or a boron atom. As the lithium salt that contains a nitrogen atom or a boron atom/ at least one kind selected from LiBF4, LiN (S02CF3) 2 andLiN (SO2C2F5) 2 ispreferred. Even more preferred combinations include a combination of LiPF6 and LiBF4; a combination of LiPF6 and LiN(S02CF3) 2; a combination of LiPF6 and LiN(S02C2F5)2, etc. When the molar ratio (LiPF«:electrolyte salt selected from LiBF4 LiN(S02CF3)2, and LiN (S02C2Fs) 2) is smaller than 70:30 in point of the proportion of LiPF6, or when the ratio is larger than 99:1 in point of the proportion of LiPF6 then the high-temperature cycle property or the suppressing effect on the generation of a gas during charged battery storing may worsen. Accordingly, the molar ratio (LiPF6: electrolyte salt selected from LiBF4, LiN(S02CF3) 2, and 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 is more effective for improving the high-temperature cycle property or the suppressing effect on the generation of a gas during charged battery storing. [31] The electrolyte salts can each be mixed at an arbitrary ratio. However, when a ratio (by mol) of the other electrolyte salts except LiBF4, LiN(S02CF3)2, and LiN(SO2C2F5)2 to all the electrolyte salts in the case where LiPF6 is used in combination with those ingredients is less than 0.01%, the high-temperature cycle property and the suppressing effect on the generation of a gas during charged battery storing are poor. When the ratio exceeds 45%, the high-temperature cycle property may worsen. Therefore, the ratio (by mol) is preferably from 0.01 to 45%, more preferably from 0.03 to 20%, still more preferably from 0.05 to 10%, and 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, roost preferably at least 0.7 M. The upper 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. [32] As the electrolyte for electric double layer capacitors (condensers), usable are known quaternary ammonium salts such as tetraethylammonium tetrafluoroborate, triethylmethylammonium tetrafluoroborate, tetraethylammonium hexafluorophosphate, etc. [33] [Production of nonaqueous electrolytic solution] The nonaqueous electrolytic solution of the present invention can be prepared, for example, by; mixing the nonaqueous solvents; adding the electrolyte salt to the mixture; and adding the fluorine-containing phenol represented by the general formula (I) so that the content of the fluorine-containing phenol in the nonaqueous electrolytic solution may be from 0.01 to 3% by mass. In this case, the nonaqueous solvent to be used, and the compound to be added to the electrolytic solution are preferably previously 1 purified within a range not significantly detracting from the producibility, in which, therefore, the impurity content is preferably as low as possible. The incorporation of, for example, air or carbon dioxide into the nonaqueous electrolytic solution of the present invention can additionally improve the high-temperature cycle property and the suppressing effect on the generation of a gas during charged battery storing. In the present invention, an electrolytic solution prepared by dissolving carbon dioxide in the nonaqueous electrolytic solution is particularly preferably used from the viewpoints of improvements in charging and discharging properties at high temperatures. Carbon dioxide is dissolved in an amount of preferably 0.001% by mass or more, more preferably 0.05% bypass Ormonde, and still more preferably 0.2% by mass or more with respect to the mass of the nonaqueous electrolytic solution. Carbon dioxide is most preferably dissolved in the nonaqueous electrolytic solution until the resultant solution saturates. [34] The nonaqueous electrolytic solution of the present invention is favorably used for the electrolytic solution for lithium primary batteries and lithium secondary batteries. Further, the nonaqueous electrolytic solution of the present invention is also usable as an electrolytic solution for electric double layer capacitors or as an electrolytic solution for hybrid capacitors. Of those, the nonaqueous electrolytic solution of the present invention is most favorable for lithium secondary batteries. [35] [Lithium Battery] The lithium battery of the present invention collectlivelymeans a lithium primary battery and a lithium secondary battery, including the nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, and is characterized in that the nonaqueous electrolytic solution contains the fluorine-containing phenol represented by the above-mentioned general formula (I) in an amount of from 0.01 to 3% by mass of the solution. As described above, the content of the fluorine-containing phenol in the nonaqueous electrolytic solution is preferably from 0.03 to 2% by mass, more preferably from 0.05 to 1.5% by mass, and still more preferably from 0.1 to 0.5% by mass. In the lithium battery of the present invention, the other constitutive components such as the positive electrode and the negative electrode except for the nonaqueous electrolytic solution can be used with no particular limitation. For example, one or more kinds selected from lithium complex metal oxides and lithium-containing olivine-type phosphates can each be used as a positive electrode active material for a lithium secondary battery. One kind of those positive electrode active materials can be used alone, or two or more kinds of them can be used in combination. The lithium complex metal oxide preferably contains one or more kinds selected from cobalt, manganese, or nickel. Specific examples thereof include LiCoOz, LiMn204, LiNi02, LiCoi-xNl„02 (0.01

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# Name Date
1 3504-CHENP-2011 PCT 23-05-2011.pdf 2011-05-23
2 3504-CHENP-2011 FORM-5 23-05-2011.pdf 2011-05-23
3 3504-CHENP-2011 FORM-3 23-05-2011.pdf 2011-05-23
4 3504-CHENP-2011 FORM-1 23-05-2011.pdf 2011-05-23
5 3504-CHENP-2011 CORRESPONDENCE OTHERS 23-05-2011.pdf 2011-05-23
6 3504-CHENP-2011 FORM-2 23-05-2011.pdf 2011-05-23
7 3504-CHENP-2011 DESCRIPTION(COMPLETE) 23-05-2011.pdf 2011-05-23
8 3504-CHENP-2011 CLAIMS 23-05-2011.pdf 2011-05-23
9 3504-CHENP-2011 ABSTRACT 23-05-2011.pdf 2011-05-23
10 3504-CHENP-2011 POWER OF ATTORNEY 04-11-2011.pdf 2011-11-04
11 3504-CHENP-2011 CORRESPONDENCE OTHERS 04-11-2011.pdf 2011-11-04
12 abstract3504-CHENP-2011.jpg 2012-07-24
13 3504-CHENP-2011 CORRSPONDENCE OTHERS 14-08-2012.pdf 2012-08-14
14 3504-CHENP-2011 FORM-18 14-08-2012.pdf 2012-08-14
15 3504-CHENP-2011-FER.pdf 2018-03-27
16 3504-CHENP-2011-AbandonedLetter.pdf 2018-11-05

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