CA2522234A1

CA2522234A1 - Electrolyte composition and cell

Info

Publication number: CA2522234A1
Application number: CA002522234A
Authority: CA
Inventors: Shouhei Matsui; Yoshihiko Wada; Katsuhito Miura; Masato Tabuchi; Miyuki Terado
Original assignee: Individual
Current assignee: Osaka Soda Co Ltd
Priority date: 2003-04-15
Filing date: 2004-04-15
Publication date: 2004-10-28
Also published as: WO2004092269A1; KR20060002984A; JPWO2004092269A1; JP4640172B2

Abstract

An electrolyte composition characterized by comprising: (1) a polymer having an ether bond as an optional ingredient; (2) an additive comprising an ether compound having ethylene oxide units as an optional ingredient; (3) a lithium salt compound; and (4) a cyclic carbonate having an unsaturated group. The electrolyte composition is excellent in processability, moldability, mechanical strength, flexibility, heat resistance, etc. and has significantly improved electrochemical properties with respect to action on lithium metal.

Description

PCT/JP2009l005370 DESCRIPTION
ELECTROLYTE COMPOSITION AND CELL
FIELD OF THE INVENTION
The present invention relates to an electrolyte composition comprising a lithium salt compound and a cyclic carbonate having an unsaturated group. More particularly, the present invention relates to an electrolyte composition which is suitable as a material for an electrochemical device such as a battery, a capacitor and a sensor, BACKGROUND ARTS
As an electrolyte constituting an electrochemical device such as a battery, a capacitor and a sensor, an electrolyte solution or a polymer electrolyte in the form a gel containing the electrolyte solution has hitherto been used in view of the ionic r_onductivity. However, the following problems are pointed out. There are a fear of damage of an apparatus arising due to liquid leakage of the electrolyte solution, and a problem that the electrolyte solution reacts with a positive electrode and a negative electrode to deteriorate electrical properties.
To the contrary, a solid electrolyte such as an inorganic crystalline substance, inorganic glass, and an organic polymer substance is suggested. The organic polymer substance is generally superior in processability and moldability and the resulting solid electrolyte has good flexibility and bending processability and, furthermore, the design freedom of the device to be applied is high and, therefore, the development thereof is expected.
However, the organic polymer substance is inferior in ionic conductivity to other materials at present.
The discovery of ionic conductivity in a homopolymer of ethylene oxide and an alkaline metal system causes the active researches of a polymer solid electrolyte.
Consequently, it is believed that a polyether such as polyethylene oxide is promising as a polymer matrix in view of high mobility and solubility of metal cation. It is expected that the ion migrates in an amorphous portion of the polymer other than a crystalline portion of the polymer.
In order to decrease the crystallinity of polyethylene oxide, various epoxides are copolymeri2ed with ethylene oxide. US-A-4,818,699 discloses a solid electrolyte comprising a copolymer of ethylene oxide and methyl glycidyl ether. However, the solid electrolyte does not always have satisfactory ionic conductivity.
JP-A-9-329114 proposes an attempt to use a polymer solid electrolyte in which a specified alkaline metal salt is incorporated into a diethyleneglyCOlmethyl glycidyl ether/ethylene oxide crosslinked material. However, this electrolyte cannot give a practically sufficient value of conductivity. W098/07772 filed by the present applicant proposes a polymer solid electrolyte comprising an aprotic organic solvent, a branched polyethylene glycol derivative or the like in order to further improve the ionic conductivity. However, when the lithium metal is used as the electrode, these electrolytes react with the lithium metal or a dendrite is precipitated on a surface of the lithium metal so that the electrical properties are remarkably deteriorated.
DISCLOSURE OF THE INVENTION
(Technical problems to be solved by the invention) An object of the present invention is to pro~tide an electrolyte composition, particularly a polymer electrolyte, excellent in ionic conductivity and electrochemical properties.
The present invention provides an electrolyte composition comprising:
(1) optionally present, a polymer having an ether linkage, (2) optionally present, an additive which comprises an ether compound having an ethylene oxide unit, (3) a lithium salt compound, and (4) a cyclic carbonate having an unsaturated group, wherein at least one of the components (1) and (2) is present.
In addition, the present invention provides a battery comprising said electrolyte composition.
We discovered that the use of electrolyte composition of the present invention can give the high-performance battery stable to a lithium metal.
(Effects Advantageous Over Prior Arts) The solid electrolyte composition of the present invention is excellent in processability, moldability, mechanical strength, softness, heat resistance and the like and its electrochemical properties to the lithium metal are remarkably improved. It can be applied to solid batteries (particularly, secondary batteries) and electronic apparatuses such as a large-capacity condenser and a display device (e. g., an electrochromic display).
PREFERRED EMBODIMENTS OF THE INVENTION
The electrolyte composition of the present invention contains at least one of the polymer (1) and the additive (2). The electrolyte composition may contain both of the polymer (1~ and the additive (2).
The ether linkage-containing polymer (1) is preferably a copolymer comprising a repeating unit of the formula (i) and a repeating unit of the formula (ii), or a copolymer comprising the repeating unit (i), the repeating unit (ii) and a crosslinkable repeating unit of the formula (iii).

5 Further, a random copolymer is preferable.
"'~ ~2~2'0 ~" ( i ) -~- CH2 ~ H-0 -~- ( i i ) wherein R1 is an alkyl group having 1 to 6 carbon atoms, a phenyl group or -CH20-Rz (wherein Rz is an alkyl group having 1 to 6 carbon atoms, a phenyl group or - (-CHz-CHz-O-) a-Rz~ or -CH [CH2-O- (-CH2-CHz-O-)b-R2~~z (wherein Rz~ is an alkyl group having 1 to 6 carbon atoms, and a and b each is an integer of 0 to 12)), ~111~
~3 R
wherein R3 is (a) a reactive silicon group, (b) a methylepoxy group, (c) an ethylenically unsaturated group, or (d) a reactive group having a halogen atom.
The monomer constituting the repeating unit (i) in the polymer (1) is ethylene oxide.

The oxirane compound constituting the repeating unit (ii) in the polymer (1) includes a gly~idyl ether compound and an alkylene oxide optionally having a substituent group.
Specific examples are an oxirane compound such as propylene oxide, methyl glycidyl ether, butyl glycidyl ether, styrene oxide, phenyl glycidyl ether and 1,2-epoxyhexane;
ethyleneglycolmethyl glycidyl ether, diethyleneglycolmethyl glycidyl ether, triethyleneglycolmethyl glycidyl ether, 1,3-bis(2-methoxyethoxy)propane-2-glycidyl ether and 1,3-bis(2-(2-methoxyethoxy)ethoxy]propane-2-glycidyl ether.
The reactive functional group in the oxirane compound forming the crosslinkable repeating unit (iii) in the polymer (1) is preferably (a) a reactive silicon group, (b) a methylepoxy group, (c) an ethylenically unsaturated group, or (d) a halogen atom.
Examples of the oxirane compound having the reactive silicon group (a) include 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxy-propyltrimethoxysilane, 4-glycidoxybutylmethyltrimethoxy-silane, 3-(1,2-epoxy)propyltrimethoxysilane, 4-(1,2-epoxy)butyltrimethoxysilane, 5-(1,2-epoxy)pentyl-trimethoxysilane, 1-(3,4-epoxycyclohexyl)methylmethyl-dimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyl-trimethoxysilane_ Among them, 3-glycidoxypropyltrimethoxy-silane and 3-glycidoxypropylmethyldimethoxysilane are preferable.
Examples of the oxirane compound having the methylepoxy group (b) include 2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether, ethylene glycol-2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether, diethylene glycol-2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether, 2-methyl-1,2,3,4-diepoxybutane, 2-methyl-1,2,4,5-diepoxypentane, 2-methyl-1,2,5,6-diepoxyhexane, hydroquinone-2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether, and catechol-2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether. Among them, 2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether and ethylene glycol-2,3-epoxypropyl-2',3'-epoxy=2'-methylpropyl ether are preferable.
Examples of the oxirane compound having the ethyhenically unsaturated group (c) include allyl glycidyl ether, 4-vinylcyclohexyl glycidyl ether, a-terpinyl glycidyl ether, cyclohexenylmethyl glycidyl ether, p vinylbenzyl glycidyl ether, allylphenyl glycidyl ether, vinyl glycidyl ether, 3,4-epoxy-1-butene, 3,4-epoxy-1 pentene, 4,5-epoxy-2-pentene, 1,2-epoxy-5,9 cyclododecadiene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy 5-cyclooctene, glycidyl acrylate, glycidyl methacrylate, glycidyl sorbinate, glycidyl cinnamate, glycidyl crotonate and glycidyl 4-hexenoate_ Allyl glycidyl ether, glycidyl acrylate and glycidyl methacrylate are preferable.

B
Examples of the oxirane compound having the halogen atom (d) include epibromohydrin, epiiodohydrin and epichlorohydrin.
The polymerization method of the polymer having the ether linkage is a polymerization method for preparing a copolymer by a ring-opening reaction of ethylene oxide moiety, and can be conducted in the same manner as in JP-A-63-154736 and JP-A-62-169823.
The polymerization reaction can be conducted as follows. The polyether copolymer can be obtained by reacting the respective monomers at the reaction temperature of 10 to 80°C under stirring, using a catalyst mainly containing an organoaluminurn, a catalyst mainly containing an organozinc, an organotin-phosphate ester condensate catalyst and the like as a ring opening polymerization catalyst in the presence or absence of a solvent. The organotin-phosphate ester condensate catalyst is particularly preferable in view of the polymerization degree or properties of the resulting copolymer. In the polymerization reaction, the reaction functional group does not react and a copolymer having the reaction functional group (1) is obtained.
The amount of the ethylene oxide constituting the repeating unit (i) may be from 10 to 95 parts by weight, preferably from 20 to 90 parts by weight, the amount of the oxirane compound constituting the repeating unit (ii) may be from 90 to 5 parts by weight, preferably 80 tn 10 parts by weight, the amount of the oxirane compound constituting the crosslinkable repeating unit (iii) may be from 0 to 30 parts by weight, preferably from 0 to 20 parts by weight, particularly from 0.1 to 20 parts by weight, based on the polymer having the ether linkage (1) used in the electrolyte composition of the present invention.
When the amount of the oxirane compound constituting the crosslinkable repeating unit (iii) is at most 30 parts by weight, the crosslinked polymer has excellent ionic conductivity.
When the amount of ethylene oxide constituting the repeating unit (i) is at least 10 parts by weight, the lithium salt compound can be easily dissolved even at a low temperature so that the ionic conductivity is high.
It is generally known that the decrease of the glass transition temperature improves the ionic conductivity, and it was found that the improvement effect of the ionic conductivity is remarkably high in the case of the polymer electrolyte composition of the present invention.
11s the molecular weight of the polymer used in the polymer electrolyte composition, the weight-average molecular weight is suitably within the range from 104 to 108, preferably from 105 to 10', so as to obtain excellent processability, moldability, mechanical strength and flexibility.
In the crosslinking method of the copolymer (1) wherein the reactive functional group is the reactive 5 silicon group (a), the crosslinking can be conducted by the reaction between the reactive silicon group and water.
In order to enhance the reactivity, there may be used, as a catalyst, organometal compounds, for example, tin compounds such as dibutyltin dilaurate and dibutyltin 10 maleate; titanium compounds such as tetrabutyl titanate and tetrapropyl titanate; and aluminum compounds such as aluminum trisacetyl acetonate and aluminum trisethyl acetoacetate; or amine compounds such as butylamine and octylamine.
Iii the crosslinking method of the copolymer (1) wherein the reactive functional group is the methylepoxy group (b), for example, polyamines and acid anhydrides can be used.
Examples of the polyamines include aliphatic polyamines such as diethylenetriamine and dipropylene-triamine; and aromatic polyamines such as 4,4'-diamino diphenyl ether, diamino diphenyl sulfone, m-phenylene-diamine and xylylenediamine. The amount of the polyamine varies depending on the type of the polyamine, but is normally within the range from 0_1 to 10 parts by weight, based on 100 parts by weight of the polymer electrolyte composition excluding a plasticizer (i.e., the additive (2) ) .
Examples of the acid anhydrides includes malefic anhydride, phthalic anhydride, methylhexahydrophthalic anhydride, tetramethylenemaleic anhydride and tetrahydro-phthalic anhydride. The amount of the acid anhydrides varies depending on the type of the acid anhydride, but is normally within the range from 0.1 to 10 parts by weight, based on 100 parts by weight of tl-ie electrolyte composition excluding the plasticizer.
In the crosslinking, an accelerator can be used_ In the crosslinking reaction of polyamines, examples of the accelerator include phenol, cresol and resorcin. In the crosslinking reaction of the acid anhydride, examples of the accelerator include benzyldimethylamine, 2-(dimethyl-aminoethyl)phenol and dimethylaniline. The amount of the accelerator varies depending on the type of the accelerator, but is normally within the range from 0.1 to 10 parts by weight, based on 100 parts by weight of the crosslinking agent.
In the crosslinking method of the copolymer (1) wherein the reactive functional group is the ethylenically unsaturated group (c), a radical initiator selected from an organic peroxide, an azo compound and the like, or active energy ray such as ultraviolet ray and electron ray is used. It is also possible to use a crosslinking agent having silicon hydride.
As the organic peroxide, there can be used those which are normally used in the crosslinking, such as ketone peroxide, peroxy ketal, hydroperoxide, dialkyl peroxide, diacyl peroxide and peroxy ester. Specific examples thereof include 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and benzoylperoxide. The amount of the organic peroxide varies depending on the type of the organic peroxide, but it is normally within the range from 0.1 to 10 parts by weight, based on 100 parts by weight of the electrolyte composition excluding the plasticizer.
As the azo compound, there can be used those which are normally used in the crosslinking, such as an azonitrile compound, an azoamide compound and an azoamidine compound, and specific examples thereof include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis(2-methyl-N-phenylpropionamidine)dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis[2-methyl-N-(2-1. 3 hydroxyethyl)propionamide], 2,2'-azobis(2-methylpropane) and 2,2'-azobis[2-(hydroxymethyl)propionitrile]. The amount of the azo compound varies depending on the type of the azo compound, but is normally within the range from 0.1 to 10 parts by weight, based on 100 parts by weight of the polymer electrolyte composition excluding the plasticizer.
In the crosslinking due to radiation of activated energy ray such as ultraviolet ray, qlycidyl acrylate ether, glycidyl methacrylate ether and glycidyl cinnamate ether are particularly preferable. Furthermore, as an auxiliary scnsitizer, there can be optionally used acetophenones such as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one and phenylketone; benzoin;
benzoin ethers such as benzoin methyl ether;
benzophenones such as benzophenone and 4-phenylbenzo-phenone; thioxanthones such as 2-isopropylthioxanthone and 2,4-dimethylthioxanthone; and azides such as 3-sulfonylazidobenzoic acid and 4-sulfonylazidobenzoic acid.
As a crosslinking accelerator, there can be optionally used ethylene glycol diacrylate, ethylene glycol dimethacrylate, oligoethylene glycol diacrylate, oligoethylene glycol dimethacrylate, allyl methacrylate, allyl acrylate, diallyl maleate, triallyl isocyanurate, bisphenylmaleimide and malefic anhydride.

As the compound having silicon hydride, which is used for crosslinking the ethylenically unsaturated group (c), a compound having at least two silicon hydrides are used_ Particularly, a polysiloxane compound or a polysilane compound is preferable.
Examples of the catalyst for the hydrosilylation reaction include transition metals such as palladium and platinum or a compound or complex thereof. ~rthermore, a peroxide, an amine and a phosphine can also be used.
The most popular catalyst includes dichlorobis(acetonitrile)palladium(II), chlorotris(triphenylphosphine)rhodium(I) and chloroplatinic acid.
In the crosslinking method of the copolymer (1) wherein the reactive functional group is the halogen atom (d), for example, a crosslinking agent such as polyamines, mercaptoimidazolines, mercaptopyrimidines, thioureas and polymercaptanes can be used. Examples of the polyamines include triethylenetetramine and hexamethylenediamine.
2U Examples of the mercaptoimidazolines include 2-mercaptoimidazoline and 4-methyl-2-mercaptoimidazoline.
Examples of the mercaptopyrimidines include 2-mercaptopyrimidine and 4,6-dimethyl-2-mercaptopyrimidine.
Examples of the thioureas include ethylene thiourea and dibutyl thiourea. Examples of the polymercaptanes include 2-dibutylamino-4,6-dimethylcapto-s-triazine and 2-phenylamino-4,6-dimercaptotriazine. The amount of the crosslinking agent varies depending on the type of the crosslinking agent, but is normally within the range from 5 0.1 to 30 parts by weight, based on 100 parts by weight of the polymer electrolyte composition excluding the plasticizer.
Furthermore, it is effective to add a metal compound as an acid acceptor to the polymer solid electrolyte in 10 view of the thermal stability of the halogen-containing polymer. Examples of the metal compound as the acid acceptor include oxide, hydroxide, carbonate, carboxylate, silicate, borate, and phosphate of Group I1 metals of the Periodic Table; and oxide, basic carbonate, basic 15 carboxylate, basic phosphate, basic sulfite, or tribasic sulfate of Group VIa metals of the Periodic Table.
Specific examples thereof include magnesia, magnesium hydroxide, magnesium carbonate, calcium silicate, calcium stearate, read lead and tin stearate. The amount of the metal compound as the above acid acceptor varies depending on the type thereof, but is normally within the range from 0.1 to 30 parts by weight, based on 100 parts by weight of the polymer electrolyte composition excluding the plasticizer_ The additive (2) comprising the ether compound having PCT/JP2004/0053'70 the ethylene oxide unit acts as the plasticizer. When the additive comprising the ether compound having the ethylene oxide unit is added to the polymer electrolyte composition, the crystallization of the polymer is prevented, the glass transition Lemperature is decreased and many amorphous phases are formed even at a low temperature to give high ionic conductivity.
Examples of the additive (2) comprising the ether compound having the ethylene oxide unit are preferably any of additives of the below-mentioned formulas (iv) to (vii).
HZ-~ (-CHZ-CHZ-O-) o-R4 R6-(-0-(~12~i2 ) e~H (iv) CHZ-O- (-~H2-~HZ-O-) d Rs R9- (-o-~H2-c'ti~-) h-o- ~ 2 ~H2.-p- (~2-CHZ-~) f R?
~~ (~-~Z~) J~H (w) Rl~ ( 0-~H2-CHZ ) i-O-C~2 CH2-~' ~-(~i2-Ctf2'~') g Rg 1-I2-ø- (-CHZ-CHZ-d-) k R 11 R13-(-0-CHZ-CH2-)m-O ~H-CH2~H (vi) R14-(-0-CHZ-CHZ-)h-O-CH2 CHZ-O-(-CH2-CH2-O-)1-R12 H -~ (-~1,1~-~CH2-U-) o_R 15 is R 1 g-- (-0-CHZ-CH2-) r-0-0112 ~ -CHZ-O- (-CN2-G7i2-0-) p R ( v i i ) Cli2--,~ (~ ~-o-) Q R 17 wherein each of R9 to R18 is an alkyl group having 1 to 6 carbon atoms, and each of c to r is a number of 0 to 12_ The amount of the additive (2) is arbitrary, and the total of the polymer (1) and the additive (2) is 100 parts by weight.
The lithium salt compound (3) used in the present invention is preferably soluble in a mixture of the polymer (1) with the additive (2), and the cyclic carbonate {4). In the present invention, the following lithium salt compounds are preferably used.
Examples of the lithium salt compound include compounds composed of a lithium ion, and an anion selected from chlorine ion, bromine ion, iodine ion, perchlorate ion, thiocyanate ion, tetrafluoroborate ion, nitrate ion, As F6-, PF6 . stearylsulfonate ion, octylsulfonate ion, dodecylbenzenesulfonate ion, naphthalenesufonate ion, dodecylnaphthalenesulfonate ion, 7,7,8,8-tetracyano-p-quin~dimethane ion, X1S03-, [ {X'S02) {X'S02)N]-, [ (XlSOz) (X2502) (X3502)0] and PCT/,7P2004/005370 X1S02) (XZS02) YC]-, wherein X1, X', X3 and Y respectively represent an electron attractive group. Preferably, X1, XZ and X3 independently represent a perfluoroalkyl or perfluoroaryl group having 1 to 6 carbon atoms and Y
represents a nitro group, a nitroso group, a carbonyl group, a carboxyl group or a cyano group. X1, X2 and X3 may be the same or different.
In the present invention, the amount of the lithium salt compound (3) is preferably from 0.1 to 1,000 parts by weight, more preferably from 1 to 500 parts by weight, based on 100 parts by weight of the total of the polymer (1) and the additive (2). When this value is at most 1,000 parts by weight, the processability and moldability, and the mechanical strength and flexibility of the resulting solid electrolyte are high, and, furthermore, the ionic conductivity is also high.
A flame retardant can be used when the flame retardance is required in the case that the electrolyte composition is used. An effective amount (for example, at most 10 parts by weight, based on lUU parts by weight of the total of the polymer (1) and the additive (2)) of those selected from halide such as a brominated epoxy compound, tetrabromobisphenol A and a chlorinated paraffin, antimony trioxide, antimony pentaoxide, aluminum hydroxide, magnesium hydroxide, phosphate ester, polyphosphate salt and zinc borate can be added as the flame retardant.
In the unsaturated group--containing Cyclic carbonate (4), the unsaturated group is generally a carbon-carbon double bond.
In the case of the lithium metal battery, the cyclic carbonate (4) reacts with the lithium metal negative electrode to form a stable layer so that the reaction between the electrolyte and the lithium metal, and the growth of the dendrite are prevented.
The cyclic carbonate (4) is preferably vinylene carbonate or a derivative thereof, or ethylene carbonate having an unsaturated group.
In the present invention, examples of vinylene carbonate and the derivative thereof are preferably a compound of the below-mentioned formula (viii-1):

2 0 ~ =C

C=0 wherein Rlg and Rz° are hydrogen or an alkyl group having 1 to 6 carbon atoms.
In the present invention, examples of the unsaturated group-containing ethylene carbonate is preferably a compound of the below-mentioned formula (viii-2):

\ /
C-C
(viii-2) "~
C=O
s wherein R21 is H or an alkyl group having 1 to 6 carbon atoms, Rz2 is an alkenyl group having 1 to 6 carbon atoms or -CH20Rz2' (wherein R'2'is an alkenyl group having 1 to 6 carbon atoms).
10 The use amount of the cyclic carbonate (4) is from 1 to 100 parts by weight, preferably from 5 to 80 parts by weight, based on 100 parts by weight of the total of the components (1) and (2) . The most suitable amount is such that a surface of the lithium metal reacts with the cyclic 15 carbonate to form a stable layer. Excess amount of the cyclic carbonate present in the polymer electrolyte composition deteriorates the electrochemical properties.
A method of incorporating the cyclic carbonate (9) is not limited, when the electrolyte compound comprising 20 the components (1), (2) and (3) is not crosslinked.
when, however, the electrolyte compound comprising the components (1), (2) and (3) is crosslinked to be used, the cyclic carbonate (4) should be impregnated after the electrolyte compound comprising the components (1), (2) and (3) is crosslinked. The electrochemical properties are not improved, if the cyclic carbonate (4) is incorporated before t2ue electrolyte compound comprising the components (1), (2) and (3) is crosslinked, and then the crosslinking is conducted. The reason therefor seems to be that the ethylenically unsaturated group of the cyclic carbonate (4) is eliminated by the crosslinking.
when the electrolyte compound comprising the components (1), (2) and (3) is crosslinked to be used, a method of impregnating the cyclic carbonate (4) is not particularly limited. Examples of the method include a method of directly impregnating the cyclic carbonate (4) into the crosslinked material of the electrolyte compound comprising the components (1), (2) and (3);
a method of impregnating a mixture of the cyclic carbonate (4) and the additive (2) into the crosslinked material;
a method of impregnating a mixture of the cyclic carbonate (4) and an organic solvent into the crosslinked material;
a method of impregnating a mixture of the electrolyte compomd comprising the components (1), (2) and thereinto; and the like.

The method for production of the polymer electrolyte composition o.f the prPSent invention is not specifically limited, and usually respective components may be mechanically mixed. In the case of the polymer (1) requiring the crosslink, the polymer electrolyte composition can be prepared, for example, by a method of crosslinking the copolymer after mechanically mixing the respective components, or a method of crosslinking the copolymer, followed by.immersing the copolymer in the additive for a long time to perform the impregmatiom. As means for mechanically mixing, various knead'ers, open roll, extruder, etc_ can be optionally used.
In case that the reactive functional group is a reactive silicon group, the amount of water used in the crosslinking reaction is not specifically limited because the crosslinking reaction easily occurs even in the presence of moisture in an atmosphere. The crosslinking can also be performed by passing through a cold water or hot water bath for a short time, or exposing to a steam atmosphere.
In case of the copolymer wherein the reactive functional group is an ethylenically unsaturated group, when using a radical initiator, the crosslinking reaction is completed at the temperature of 10°C to 200°C within 1 minute to 20 hours. Furthermore, when using energy ray such as ultraviolet ray, a sensitizer is generally used.
The crosslinking reaction is normally completed at the temperature of 10°C to 150°C within 0.1 second to 1 hour.
In case of the crosslinking agent having silicon hydride, the crosslinking reaction is completed at the temperature of 10°C to 180°C within 10 minutes to 10 hours.
A method of mixing the lithium salt compound (3) and the additive (2) with the polymer (1) (that is, the polyether copolymer) is not specifically limited. An organic solvent can be used, if necessary. In the production using the organic solvent, various polar solvents such as tetrahydrofuran, acetone, acetonitrile, dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone and methyl isobutyl ketone may be used alone or in combination thereof.
The polymer electrolyte composition of the present invention is superior in mechanical strength and flexibility, and a large area thin-film shaped solid electrolyte can be easily obtained by utilizing the properties of the electrolyte composition. For example, it is possible to make a battery by using the polymer electrolyte composition of the present invention. In this case, examples of a positive electrode material include lithium-manganese complex oxide, lithium cobaltate, vanadium pentaoxide, olivin-type iron phosphate, polyacetylene, polypyrene, polyaniline, polyphenylene, polyphenylene sulfide, polyphenylene oxide, polypyrrole, polyfuran, and polyazulene. Examples of a negative electrode material include an interlaminar compound prepared by occlusion of lithium between graphite or carbon layers, a lithium metal and a lithium-lead alloy. By utilizing high ion conductivity, the polymer electrolyte composition can also be used as a diaphragm of an ion electrode of a ration such as alkaline metal ion, Cu ion, Ca ion, and Mg ion. The polymer electrolyte composition of the present invention is particularly suitable as a material for electrochemical device such as a battery, a capacitor and a sensor.
EXAMPLES
The following Examples further illustrate the present invention.
The composition in terms of monomer of the polyether copolymer was determined by 1H NMR spectrum. In case of the measurement of the molecular weight of the polyether copolymer, a gel permeation chromatography measurement was conducted and the molecular weight was calculated in terms of standard polystyrene_ The gel permeation chromatography measurement was conducted at 60°C by a measuring device RID-6A manufactured by Shimadzu Corp., using a column manufactured by Showa Denko K.K. such as Showdex KD-807, KD-806, KD-806M and KD-803, and dimethylformamide (DMF) as a solvent. The glass 5 transition temperature was measured by DSC 220 manufactured by Seiko Denshi Industry Co. Ltd. and the fusion heat was measured by a differential scanning calorimeter DSC 7 manufactured by PerkinElmer, Inc., both measurements being in a nitrogen atmosphere within the 10 temperature range from -100 to 80°C at a heating rate of 10°C/min. For the measurement of the electrical conductivity 6, a sample film was previously vacuum-dried at 30°C for 12 hours. The electrical conductivity was measured at 10°C with sandwiched between stainless steel 15 electrodes, and the conductivity was calculated according to the complex impedance method, using an A.C. method (voltage: 30 mV, frequency: 10 Hz to 10 MHz).
The evaluation of the stability to a lithium metal in the battery is determined by a lithium plating and 20 stripping cycle efficiency test. A charge/discharge tester BTS-2004W manufactured by Nagano Ltd. was used for the lithium plating and stripping cycle efficiency test.
A copper foil and a lithium metal as counter electrode were used, a polymer electrolyte composition was 25 sandwiched between two electrodes to prepare a test cell.

Li was plated at room temperature at the electric current density of 0.1 mA/cm2 for 10 hours, and then Li was stripped at the electric current density of 0.1 mA/cm2 until a terminal voltage of 2.0 V. The lithium plating and stripping cycle efficiency was calculated according to the following formula:
Lithium plating and stripping cycle efficiency ($) -(time required for stripping at n cycles/
time required for plating at n cycles) x 100 Preparation Example (Production of catalyst) Tributyltin chloride (10 g) and tributyl phosphate (35 g) were charged in a three-necked flask equipped with 25 a stirrer, a thermometer and a distillation device, and the mixture was heated at 250°C for 20 minutes while stirring under a nitrogen stream and the distillate was distilled off to obtain a solid condensate as a residue product. In the following, this condensate was used as a polymerization catalyst.
Polymerization Example 1 (Preparation of polymer) After the atmosphere in a four-necked glass flask (internal volume: 3 L) was replaced by nitrogen, the condensate (2 g) obtained in the above Preparation Example as a catalyst, methyl glycidyl ether (100g) having a water content adjusted to not more than 10 ppm and n-hexane (1,000 g) as a solvent were charged in the flask. Ethylene oxide (200 g) was gradually added with monitoring the polymerization degree of methyl glycidyl ether by gas chromatography. The polymerization reaction was terminated by using methanol. A polymer was isolated by decantation, dried at 40°C under a normal pressure for 24 hours, and then dried at 45°C under reduced pressure for 10 hours to give 275 g of the polymer. This copolymer had the glass transition temperature of -65°C, the weight-average molecular weight of 1,100,000 and the fusion heat of 7 J/g. 1H NMR spectrum analysis revealed that the composition in terms of monomer of this copolymer had ethylene oxide of 67 wt~ and methyl glycidyl ether of 33 wt%.
Polymerization Example 2 (Preparation of polymer) After the atmosphere in a four-necked glass flask (internal volume: 3 L) was replaced by nitrogen, the condensate (2 g) obtained in the above Preparation Example as a catalyst, propylene oxide (100g) having a water content adjusted to not more than 10 ppm, glycidyl methacrylate (10 g) and n-hexane (1,000 g) as a solvent were charged in the flask. Ethylene oxide (200 g) was gradually added with monitoring the polymerization degree of propylene oxide by gas chromatography. The polymerization reaction was terminated by using methanol.
A polymer was isolated by decantation, dried at 40°C
under a normal pressure for 24 hours, and then dried at 45°C under reduced pressure for 10 hours to give 283 g of the polymer. This copolyrncr had the glass transition temperature of -68°C, the weight-average molecular weight of 1,700,000 and the fusion heat of 7 J/g. 1H NMR
spectrum analysis revealed that the composition in terms of monomer of this copolymer had ethylene oxide of 67 wt~
propylene oxide 30 wt~ and glycidyl methacrylate of 3 wt%.
Polymerization Example 3 (Preparation of polymer) After the atmosphere in a four-necked glass flask (internal volume: 3 L) was replaced by nitrogen, the condensate (2 g) obtained in the above Preparation Example as a catalyst, an oxirane compound (EM) (180g) of the below-mentioned formula (ix) having a water content adjusted to not more than 10 ppm, allyl glycidyl ether (20 g) and n-hexane (1,000 g) as a solvent were charged in the flask. Ethylene oxide (120 g) was gradually added with monitoring the polymerization degree of EM by gas chromatography. The polymerization reaction was terminated by using methanol. A polymer was isolated by decantation, dried at 40°C under a normal pressure for 24 hours, and then dried at 45°C under reduced pressure for hours to give 29B g of the polymer. This copolymer had the glass transition temperature of -72°C, the 5 weight-average molecular weight of 1,300,000 and the fusion heat of 3 J/g. 1H NMR spectrum analysis revealed that the composition i.n terms of monomer of this copolymer had ethylene oxide of 37 wto, EM of 57 wt$ and allyl glycidyl ether of 6 wt~.
2-CIf~I2-O-CH2-O-(-CH2-~H2-O-)2-~H3 (ix) O
EM
Polymerization Example 4 (Preparation of polymer) After the atmosphere in a four-necked glass flask (internal volume: 3 L) was replaced by nitrogen, the condensate (2 g) obtained in the above Preparation Example as a catalyst, an oxirane compound (GM) (100g) of the below-mentioned formula (x) having a water content adjusted to not more than 10 ppm, allyl glycidyl ether (10 g) and n-hexane (1,000 g) as a solvent were charged in the flask. Ethylene oxide (120 g) was gradually added with monitoring the polymerization degree of GM by gas chromatography. The pclymerization reaction was terminated by using methanol. A polymer was isolated by decantation, dried at 40°C under a normal pressure for 24 hours, and then dried at 45°C under reduced pressure for 10 hours to give 205,g of the polymer. This copolymer 5 had the glass transition temperature of -74°C, the weight-average molecular weight of 1,150,000 and the fusion heat of 3 J/g. 1H NMR spectrum analysis revealed that the composition in terms of monomer of this copolymer had ethylene oxide of 53 wt$, GM of 43 wt~ and 10 allyl glycidyl ether of 4 wt~.
~2~ (~2~2~) 2 ~3 \ Z-CH-CH2-0-CH (x) CH2 O- (~H2-CHZ-0-) 2-CH3 GI~
Example 1 15 1 g of the ethylene oxide/methyl glycidyl ether binary copolymer having the weight.-average molecular weight of 1,100,000 obtained in Polymerization Example l, 2 g of the additive comprising an ether compound represented by the below-mentioned formula (iv-1) having ethylene oxide units, 20 and 0.7 g of lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) as a lithium salt compound were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on both surfaces of a porous film having the thickness of 20 um. The coating was dried at a reduced pressure at 30°C for 12 hours to give an electrolyte film having a thickness of 60 ~.~.m and containing the porous film.
N2~ t~H2~2~) 2~3 CH3 0-~CHZ-CHI ~N (iv-1) CHZ-O-(-CH2-CH2-0-)2-CH3 Example 2 1 g of the ethylene oxide/propylene oxide/glycidyl methacrylate ternary copolymer having the weight-average molecular weight of 1,700,000 obtained in Polymerization Example 2, 2 g of the additive comprising an ether compound represented by the above-mentioned formula (iv-1) having ethylene oxide units, 0.7 g of lithium bis(trifluoro-methylsulphonyl)imide (LiTFSI) as a lithium salt compound, 0.015 g of benzoyl peroxide as an initiator, and 0.3 g of ethyleneglycol diacrylate as a crosslinking accelerator were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a PET

PCT/JP2nn4/00537n film. The coating was dried at a reduced pressure at 30°C
for 12 hours and heated at 100°C for 3 hours under nitrogen atmosphere to give a crosslinked electrolyte film having a thickness of 50 ~zm.
Example 3 1 g of the ethylene oxide/EM/allyl glycidyl ether ternary copolymer having the weight-average molecular weight of 1,300,000 obtained in Polymerization Example 3, 2 g of the additive comprising an ether compound represented by the below-mentioned formula (vii-1) having ethylene oxide units, 0.8 g of lithium bis(perfluoro-ethylsulphonyl)imide (LiBETI) as a lithium salt compound, 0.015 g of benzoyl peroxide as an initiator, and 0_3 g of ethyleneglycol diacrylate as a crosslinking accelerator were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a PET
film. The coating was dried at a reduced pressure at 30°C
for 12 hours and heated at 100°C for 3 hours under nitrogen atmosphere to give a crosslinked electrolyte film having a thickness of 50 um.

H2-0-CH2-CH2_(~--CH3 CH3-0-Cli2-CH2-0-CH2~-CHI-U-CHZ-CH2-0 -~H3 (vii-1) CHZ-~-CHZ--CHZ-0-CH3 Example 4 1 g of the ethylene oxide/GM/allyl glycidyl ether ternary copolymer having the weight-average molecular weight of 1,300,000 obtained in Polymerization Example 4, 2 g of the additive comprising an. ether compound represented by the above-mentioned formula (vii-1) having ethylene oxide units, 0.8 g of lithium bis(perfluoro-ethylsulphonyl)imide (LiBETI) as a lithium salt compound, 0.015 g of benzoyl peroxide as an initiator, and 0.3 g of ethyleneglycol diacrylate as a crosslinking accelerator were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a PET
film. The coating was dried at a reduced pressure at 30°C
for 12 hours and heated at 100°C for 3 hours under nitrogen atmosphere to give a CrOSSlinked electrolyte film having a thickness of 50 um.
Example 5 0.02 g of the ether compound of the above-mentioned formula (iv-1) having ethylene oxide units, which contained 5 wt$ of vinylene carbonate, was impregnated into 0.01 g of the electrolyte film prepared in Example 1 to give an electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 83~.
The results are shown in Table 1.
Example 6 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 10 wt~ of vinylene carbonate and 1 M lithium bis(trifluoromethylsulphonyl)imide (LiTFSI), was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 2 to give an electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 84~. The results are shown in Table 1.
Example 7 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 20 wt$ of vinylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 3 to give an electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 920. The results are shown in Table 1.

3~
Example 8 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which S contained 40 wt~ of vi-nylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 3 to give an electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 91$. The results are shown in Table 1.
Example 9 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 60 wt~ of vinylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 4 to give an electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 91~. The results are shown in Table 1.
Comparative Example 1 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which did not contain vinylene carbonate, was impregnated into 0.01 g of the electrolyte film prepared in Example 2 to give an electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 62~.
The results are shown in Table 1_ Comparative Example 2 1 g of the ethylene oxide/EM/allyl glycidyl ether ternary copolymer having the weight-average molecular weight of 1,300,000 obtained in Polymerization Example 3, 2 g of the additive comprising an ether compound represented by the above-mentioned formula (iv-1) having ethylene oxide units, 0.7 g of lit2iium bis(trifluoromethylsulphonyl)imide (LiTFSI) as a lithium salt compound, 0.015 g of benzoyl peroxide as an initiator, 0.3 g of ethyleneglycol diacrylate as a crosslinking accelerator, and 20 wt~, based on an electrolyte, of vinylidene carbonate were mixed with 1~ 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a PET film. The coating was dried at a reduced pressure at 30°C for 12 hours and heated at 100°C for 3 hours under nitrogen atmosphere to give a crosslinked electrolyte composition having a thickness of 50 um. The average value of a lithium plating and stripping cycle efficiency of the crosslinked electrolyte composition was 60~. The results are shown in Table 1.
Comparative Example 3 1 g of the ethylene oxide/GM/allyl glycidyh ether ternary copolymer having the weight-average molecular weight of 1,300,000 obtained in Polymerization Example 4, 2 g of the additive comprising an ether compound represented by the above-mentioned formula (vii-1) having ethylene oxide units, 0.8 g of lithium bis(perfluoro-ethylsulphonyl)imide (LiBETI) as a lithium salt compound, 0.015 g of benzoyl peroxide as an initiator, and 0.3 g of ethyleneglycol diacrylate as a crosslinking accelerator, and 5o wt~, based on an electrolyte, of vinylidene carbonate were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a PET film. The coating was dried at a reduced pressure at 30°C for 12 hours and heated at 100°C for 3 Z5 hours under nitrogen atmosphere to give a crosslinked electrolyte film having a thickness of 55 um. The average value of a lithium plating and stripping cycle efficiency of the crosslinked electrolyte composition was 67%. The results are shown in Table 1.
Comparative Example 4 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 120% o~ vinylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 2 to give an electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 71%. The results are shown in Table 1.

Table Vinylene Lithium stripping cycle plating and carbonate efficiency amount (wt%) First Maximum(o) Average($) time (%) Ex. 5 5 80 85 83 Ex. 6 10 83 86 84 Ex 7 2 U 91 93 92 .

Ex. 8 40 90 93 91 Ex. 9 60 90 92 91 C. Ex. 1 0 46 65 62 C. Ex. 2 20 49 63 60 C. Ex. 3 50 50 71 67 C. Ex. 4 120 36 79 71 The average value was calculated from lithium plating and stripping cycle efficiencies until 20th cycle.
Example 10 By using the electrolyte composition obtained in Example 6 as an electrolyte, a lithium metal foil as a negative electrode and lithium cobaltate (LiCo02) as a positive electrode active material, a secondary battery 25 was prepared.
Lithium cobaltate was prepared by mixing predetermined amounts of lithium carbonate and cobalt carbonate powder and then calcining the mixture at 900°C

for 5 hours. The calcined mixture was ground, and then 5 parts by weight of acetylene black, 10 parts by weight of the polymer obtained in Polymerization Example 2 and 5 parts by weight of lithium bis(trifluoromethylsulphonyl)-imide (LiTFSI) were added to 85 parts by weight of resultant lithium cobaltate, mixed with rolls and press-molded under a pressure of 30 MPa to give a film which was a positive electrode of the battery.
The electrolyte composition obtained in Example 6 was sandwiched between the lithium metal foil and the positive electrode plate, and the charge/discharge characteristics of the resulting battery were examined at room temperature with applying a pressure of 1 MPa so that the interfaces were brought into intimate contact with each other. The charge was conducted at an upper limit voltage of 4.2 V under a constant current and voltage condition, and the discharge was conducted under a constant current. The discharge current density was 0.1 mA/cm2 and the charge was conducted at 0.1 mA/em2. A
discharge capacity after 100 cycles of charge-discharge was 90% of an initial capacity.
Example 11 A secondary battery was produced by using the electrolyte composition obtained in Example 7, a lithium metal foil as a negative electrode, and the positive electrode prepared in Example 10. The charge-discharge properties were examined in the same manner. A discharge capacity after 100 cycles of charge-discharge was 91~ of 5 an initial capacity.
Comparative Example 5 A secondary battery was produced by using the electrolyte composition obtained in Comparative Example 1, 10 a lithium metal foil as a negative electrode, and the positive electrode prepared in Example 10. The charge-discharge properties were examined in the same manner. A
discharge capacity after 100 cycles of charge-discharge was 80~ of an initial capacity.
Comparative Example 6 A secondary battery was produced by using the electrolyte composition obtained in Comparative Example 3, a lithium metal fo~7 as a negative electrode, and the positive electrode prepared in Example 10. The charge-discharge properties were examined in the same manner. A
discharge capacity after 100 cycles of charge-discharge was 78~ of an initial capacity.
Example 12 Vinylene carbonate (0.004 g, 3 wt~) and an ether compound of the below-mentioned formula (iv-1) having ethylene oxide units (0.116 g, 97 wt$), and lithium bis(perfluoroethylsulphonyl)imide (LiBETI) (0.08 g) were used to give an electrolyte, which had the average of the lithium plating and stripping cycle efficiency of 86~. The results are shown in Table 2.
H2~ ~~H2~2~~ 2~3 CH3-0-CHZ-i;H2 -~0- ~ H ( i v- I ) CIi2-O- (-CH2-CH2-0-) 2-CH3 Example 13 The same manner as in Example 12 was repeated to give an electrolyte except that vinylene carbonate (0.006 g, S
wt$) and the ether compound of the above-mentioned formula (iv-1) having ethylene oxide units (0.114 g, 95 wt$) were used. The electrolyte had the average of the lithium plating and stripping cycle efficiency of 91$. The results are shown in Table 2.
Example 14 The same manner as in Example 12 was repeated to give an electrolyte except that vinylene carbonate (0.012 g, 10 wt%) and the ether compound of the above-mentioned formula (iv-1) having ethylene oxide units (0.108 g, 90 wt~) were used. The electrolyte had the average of the lithium plating and stripping cycle efficiency of 92~. The results are shown in Table 2.
Example 15 Vinylene carbonate (0.014 g, 10 wtg) and an ether compound of the below-mentioned formula (vii-1) having ethylene oxide units (0.1268, 90 wt~), and lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) (0.06 g) were used to give an electrolyte, which had the average of the lithium plating and stripping cycle efficiency of 92~. The IS results are shown in Table 2.
~H2-4-CH2-CH2-4-CH3 CH3-0-Cli2-CH2-0-CHZ ~-CHZ-O-CH2-CH2-0 -CH3 (vii-1) CHZ-0-CH2-CH2-o--CH3 Example 16 The same manner as in Example 12 was repeated to give an electrolyte except that Vinylene carbonate (0.024 g, 20 wt$) and the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units (0.096 g, 80 wt%) were used. The electrolyte had the average of the lithium plating and stripping cycle efficiency of 91$. The results are shown in Table 2.
Example 17 The same manner as in Example 12 was repeated to give an electrolyte except that vinylene carbonate (0.060 g, 50 wt%) and the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units (0.060 g, 50 wt%) were used. The electrolyte had the average of the lithium plating and stripping cycle efficiency of 91°a. The results are shown in Table 2.
Example 1B
The same manner as in Example 12 was repeated to give an electrolyte except that vinylene carbonate (0.096 g, 80 wt%) and the ether compound of the above-mentioned formula (vii-1) having ethylene oxide uW is (0.024 g, 20 wt%) were used. The electrolyte had the average of the lithium plating and stripping cycle efficiency of 88%. The results are shown in Table 2.
Comparative Example 7 An electrolyte containing the ether compound of the above-mentioned formula (iv-1) having ethylene oxide units (0_12 g) and LiBETI (0.08 g) had the average of the lithium plating and stripping cycle efficiency of 71$. The results are shown in Table 2.
Comparative Example 8 An electrolyte containing the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units (0.14 g) and LiTFSI (0.06 g) had the average of the lithium plating and stripping cycle efficiency of 54$. The results are shown in Table 2.
Table 2 Vinylene Lithium Lithium carbonate salt plating and stri ping c cle efficienc amount compound Initial Maximum Average (wt$) ($) ($) ($) Ex. 12 3 LiBETI 82 90 86 Ex. 13 5 LiBETI 83 92 91 Ex. 14 10 LiBETI 85 94 92 Ex. 15 10 LiTFSI 86 94 92 Ex. 16 20 LiBETI 82 93 91 Ex. 17 50 LiBETI 83 94 91 Ex. 18 80 LiBETI 88 95 88 Com. Ex. 0 LiBETI 67 78 71 Com. Ex. 0 LiTFSI 55 64 54 The average value was calculated from lithium plating and stripping cycle efficiencies until 20th cycle.
Example 19 By using a porous separator (E25MMS manufactured by Tonen Tapyrus Co., Ltd., thickness: 25 um, porosity: 38%) impregnated with the electrolyte obtained in Example 13, a lithium metal foil as a negative electrode and lithium 5 cobaltate as a positive electrode active material, a secondary battery was prepared.
Lithium cobaltate was prepared by mixing predetermined amounts of lithium carbonate and cobalt carbonate powder and then calcining the mixture at 900°C
10 for 5 hours. The calcined mixture was ground, and then 4 parts by weight of acetylene black and 6 parts by weight of polyvinylidene fluoride were added to 90 parts by weight of resultant lithium cobaltate, mixed with rolls and press-molded under a pressure of 30 MPa to give a 15 film which was a positive electrode of the battery.
The porous separator impregnated with the electrolyte obtained in Example 13 was sandwiched between the lithium metal foil and the positive electrode plate, and the charge/discharge characteristics of the resulting 20 battery were examined at 2S°C with applying a pressure of 1 MPa so that the interfaces were brought into intimate contact with each other. The charge was conducted at a current density of 0.1 mA/cm2 and an upper limit voltage of 4.2 V under a constant current and voltage condition, 25 and the discharge was conducted at a current density of 0.1 mA/cm2 under a constant current. A discharge capacity after 100 cycles of charge-discharge was 85$ of an initial capacity.
Example 20 A secondary battery was prepared by using a porous separator impregnated with the electrolyte prepared in Example 15, a lithium metal foil as a negative electrode, and the positive electrode prepared in Example 19. The charge/discharge properties were examined as in Example 19. A discharge capacity after 100 cycles of charge-discharge was 88$ of an initial capacity.
Comparative Example 9 A secondary battery was prepared by using a porous separator impregnated with the electrolyte prepared in Comparative Example 7, a lithium metal foil as a negative electrode, and the. positive electrode prepared in Example 19. The charge/discharge properties were examined as in Example 19. A discharge capacity after 100 cycles of charge-discharge was 69$ of an initial capacity.
Comparative Example 10 A secondary battery was prepared by using a porous separator impregnated with the electrolyte prepared in Comparative Example 8, a lithium metal foil as a negative electrode, and the positive electrode prepared in Example 19. The charge/discharge properties were examined as in Example 19. A discharge capacity after 100 cycles of charge-discharge was 43~ of an initial capacity.
Example 21 1 g of the ethylene oxide/methyl glycidyl ether binary copolymer having the weight-average molecular weight of 1,100,000 obtained in Polymerization Example 1, 2 g of the additive comprising an ether compound represented by the below-mentioned formula (iv-1) having ethylene oxide units, and 0.7 g of lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) as a lithium salt compound were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on both surfaces of a porous film having the thickness of 20 ~.un. The coating was dried at a reduced pressure at 30°C for 12 hours to give an electrolyte film having a thickness of 60 um and containing the porous film.
H2-0- (-CH2-Gli2-0-) 2-CH3 CH3 D-CH2-~i2 (iv-1) ~2~ (~H2~2~~ 2~3 PCT/,7P2004/0053'7(7 Example 22 1 g of the ethylene oxide/propylene oxide/glycidyl methacrylate ternary copolymer having the weight-average molecular weight of 1,700,000 obtained in Polymerization Example 2, 2 g of the additive comprising an ether compound represented by the above-mentioned formula (iv-1) having ethylene oxide units, 0.7 g of LiTFSI as a lithium salt compound, 0.015 g of benzoyl peroxide as an initiator, and 0.3 g of ethyleneglycol diacrylate as a crosslinking accelerator were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a polyethylene terephthalate resin (PET) film.
The coating was dried at a reduced pressure at 30°C for 12 hours and heated at 100°C for 3 hours under nitrogen atmosphere to give a crosslinked electrolyte film having a thickness of 50 ~.un.
Example ~3 1 g of the ethylene oxide/EM/a11y1 glycidyl ether ternary copolymer having the weight-average molecular weight of 1,300,000 obtained in Polymerization Example 3, 2 g of the additive comprising an ether compound represented by the below-mentioned formula (vii-1) having ethylene oxide units, 0_8 g of lithium bis(perfluoro-ethylsulphonyl)imide (LiBETI) as a lithium salt compound, 0.015 g n.f ben~oyl peroxide as an initiator, and 0.3 g of ethyleneglycol diacrylate as a crosslinking accelerator were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a PET
film. The coating was dried at a reduced pressure at 30°C
for 12 hours and heated at 100°C for 3 hours under nitrogen atmosphere to give a crosslinked electrolyte film having a thickness of 50 ~.zm.
~H2-U-CH2-CHZ-0-~H3 CH3 0-CHZ-CH2-0-CH2~-Cfi2-0-CH2-CHZ-0 -CH3 (vii-1) CHZ-fl-CHZ-CH2-0-CH3 Example 24 1 g of the ethylene oxide/GM/allyl glycidyl ether ternary copolymer having the weight-average molecular weight of 1,300,000 obtained in Polymerization Example 4, 2 g of the additive comprising an ether compound represented by the above-mentioned formula (vii-1) having ethylene oxide units, 0.8 g of LiBETI as a lithium salt compound, 0.05 g of lithium borofluoride (LiBF4), 0.015 g of benzoyl peroxide as an initiator, and 0.3 g of ethyleneglycol diacrylate as a crosslinking accelerator were mixed with 50 g of acetonitrile to give a homogeneous mixture, and then the mixture was uniformly coated on a PET film. The coating was dried at a reduced pressure at 30°C for 12 hours and heated at 100°C for 3 hours under nitrogen 5 atmosphere t~ give a crosslinked electrolyte film having a thickness of 50 um.
Example 25 0.02 g of the ether compound of the above-mentioned 10 formula (iv-1) having ethylene oxide units, which contained 6 wt~ of vinylethylene carbonate, was impregnated into 0.01 g of the electrolyte film prepared in Example 21 to give a polymer electrolyte composition which had the average of lithium plating and stripping 15 cycle efficiency of 750. The results are shown in Table 3.
Example 26 0.02 g of the ether compound of the above-mentioned 20 formula (vii-1) having ethylene oxide units, which contained 12 wt~ of vinylethylene carbonate and 1 mol/kg LiTFSI, was impregnated into 0.01 g of the crosslinked electrolyte film excluding the PET film prepared in Example 22 to give a polymer electrolyte composition 25 which had the average of lithium plating and stripping cycle efficiency of 82$. The results are shown in Table 3.
Example 27 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 18 wt$ of vinylethylene carbonate, was impregnated into 0.01 g of the crosslinked~electrolyte film prepared in Example 23 to give a polymer electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 91~. The results are shown in Table 3.
Example 28 0,02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 20 wto of vinylethylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 24 to give a polymer electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 93$. The results are shown in Table 3.
Example 29 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 50 wt$ of vinylethylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 24 to give a polymer electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 90$. The results are shown in Table 3.
Comparative Example 11 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which did not contain vinylethylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 22 to give a polymer electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 62$. The results are shown in Table 3.
Comparative Example 12 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 20 wt~ of ethylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 23 to give a polymer electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 58~. The results are shown in Table 3.
Comparative Example 13 0.02 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 20 wt~ of propylene carbonate, was impregnated into 0.02 g of the crosslinked electrolyte film prepared in Example 23 to give a polymer electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 380. The results are shown in Table 3.
Comparative Example 14 O.U2 g of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, which contained 120 wt~ of vinylethylene carbonate, was impregnated into 0.01 g of the crosslinked electrolyte film prepared in Example 22 to give a polymer electrolyte composition which had the average of lithium plating and stripping cycle efficiency of 65$. The results are shown in Table 3.

PCT/JP2009/(705370 Table 3 Vinylethylene Lithium carbonate plating and stripping cycle efficient Amount (wt%) Initial Maximum Average (~) Ex. 25 6 68 80 75 Ex. 26 12 80 84 82 Ex. 27 18 89 93 91 Ex. 28 20 91 94 93 Ex. 29 50 88 92 90 Com. Ex. 0 46 65 62 Com. Ex. 0 46 61 58 Com. Ex. 0 26 58 38 Com. Ex. 120 55 71 65 The average value was calculated from lithium plating and stripping cycle efficiencies until 20th cycle.
Example 30 By using the polymer electrolyte composition obtained in Example 26, a lithium metal foil as a negative electrode and lithium cobaltate (LiCoOZ) as a positive electrode active material, a secondary battery was prepared.
Lithium cobaltate was prepared by mixir~g predetermined amounts of lithium carbonate and cobalt carbonate powder and then calcining the mixture at 900°C
for 5 hours. The calcined mixture was ground, and then 5 parts by weight of acetylene black, 10 parts by weight of the polymer obtained in Polymerization Example 2 and 5 parts by weight of LiTFSI were added to 85 parts by weight of resultant lithium cobaltate, mixed with rills and press-molded under a pressure of 30 MPa to give a film which was a positive electrode of the battery.
The polymer electrolyte composition obtained in Example 26 was sandwiched between the lithium metal foil and the positive electrode plate, and the 5 charge/discharge characteristics of the resulting battery were examined at room temperature with applying a pressure of 1 MPa so that the interfaces were brought into intimate contact with each other. The charge was conducted at a constant current and a constant voltage of 10 at most 4.2 V, and the discharge was conducted at a constant current. The discharge current was 0.1 mA/cm2 and the charge was conducted at 0.1 mA/cm2. A discharge capacity after 100 cycles of charge-discharge was 90~ of an initial capacity.
Example 31 A secondary battery was produced by using the polymer electrolyte composition obtained in Example 28, a lithium metal foil as a negative electrode, and the positive electrode prepared in Example 30. The charge-discharge properties were examined in the same manner. A
discharge capacity after 100 cycles of charge-discharge was 91~ of an initial capacity.
Comparative Example 15 A secondary battery was produced by using the polymer electrolyte composition obtained in Comparative Example 11, a lithium metal foil as a negative electrode, and the positive electrode prepared in Example 30. The charge-discharge properties were examined in the same manner. A discharge capacity after 100 cycles of charge-discharge was 80$ of an initial capacity.
Example 32 IO 0.116 g (97 wt~) of the ether compound of the below-mentioned formula (iv-2) having ethylene oxide units, which contained 0.004 g (3 wt$) of vinylethylene carbonate, and lithium bis(perfluoroethylsulphonyl)imide (LiHETI) were used to give an electrolyte which had the average of lithium plating and stripping cycle efficiency of 82~. The results are shown in Table 4.
H2-8- C-CH2-CH2-0-)3 -CH3 CH3-0-~i2-CH2 -0-~ H
CH2--o- <-CH2~H2-0-)3 -CH3 Example 33 An electrolyte was prepared in the same manner as in Example 32 except that 0.114 g (95 wt~) of the ether PCT/3P2004/0053~0 compound of the above-mentioned formula (iv-2) having ethylene oxide units and 0_006 g (5 wt$) of vinylethylene carbonate were used. The electrolyte had the average of lithium plating and stripping cycle. efficiency of 88$.
The results are shown in Table 4.
Example 34 An electrolyte was prepared in the same manner as in Example 32 except that 0.108 g (90 wt$) of the ether compound of the above-mentioned formula (iv-2) having ethylene oxide units and 0.012 g (10 wt$) of vinylethylene carbonate were used. The electrolyte had the average of lithium plating and stripping cycle efficiency of 93$. The results are shown in Table 4.
Example 35 0.126 g (90 wt$) of the ether compound of the below-mentioned formula (vii-1) having ethylene oxide units, 0.014 g (10 wt$) of vinylethylene carbonate, 0.054 g of lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) and 0.001 g of lithium borofluoride (LiBFq) were used to give an electrolyte which had the average of lithium plating and stripping cycle efficiency of 90$. The results are shown in Table 4.

~HZ-0-CH2-CHZ-0-CH3 CH3-0-CIi2-CHZ-fl-CH2 -CHZ-0-CH2-CH2-0 -CH3 (v i i-1) Example 36 An electrolyte was prepared in the same manner as in Example 35 except that 0.096 g (80 wt~) of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, and 0.024 g (20 wt$) of vinylethylene carbonate were used. The electrolyte had the average of lithium plating and stripping cycle efficiency of 89$. The results are shown in Table 4.
Example 37 An electrolyte was prepared in the same manner as in Example 32 cxccpt that 0.060 g (50 wt~) of the ether compound of the above-mentioned formula (vii-1) having ethylene oxide units, and 0.060 g (50 wt~) of vinylethylene carbonate were used. The electrolyte had the average of lithium plating and stripping cycle efficiency of 92°s. The results are shown in Table 4.

PC:T/JP2n04/ 005370 Table 4 Vinyl- Lithium Lithium plating and ethylene salt stripping cycle efficiency carbonate compound Initial Maximum Average amount ( m o 1 / k ( $ ) ( ~; ) ( ~ ) g ) (wt$) Ex. 3 LiBETI=1.0 80 88 82 Ex. 5 LiBETI=1.0 82 92 88 Ex. 10 LiBETI=1.0 87 96 93 Ex . 1 0 L i T F S I 84 93 90 = 1 . 0 3 5 LiBF9=0 . 05 Ex. 20 LiTFSI=1. 0 82 93 89 3 6 LiBFq=0 . 05 E 50 LiBETI=1 . 85 94 92 . 0 ~ I ~ ~ ~
~

The average value was calculated from lithium plating and stripping cycle efficiencies until 20th cycle.

Claims

1. An electrolyte composition comprising:
(1) optionally present, a polymer having an ether linkage, (2) optionally present, an additive which comprises an ether compound having an ethylene oxide unit, (3) a lithium salt compound, and (4) a cyclic carbonate having an unsaturated group, wherein at least one of the components (1) and (2) is present.

2. The electrolyte composition according to claim 1, wherein the ether linkage-containing polymer (1) is a copolymer comprising a repeating unit of the below-mentioned formula (i) and a repeating unit of the below-mentioned formula (ii), and/or a copolymer comprising the repeating unit (i), the repeating unit (ii) and a crosslinkable repeating unit of the below-mentioned formula (iii):

wherein R1 is an alkyl group having 1 to 6 carbon atoms, a phenyl group or -CH2O-R2 (wherein R2 is an alkyl group having 1 to 6 carbon atoms, a phenyl group or -(-CH2-CH2-O-)a-R2' or -CH[CH2-O-(-CH2-CH2-O-)b-R2']2 (wherein R2' is an alkyl group having 1 to 6 carbon atoms, and a and b each is an integer of 0 to 12)), wherein R3 is (a) a reactive silicon group, (b) a methylepoxy group, (c) an ethylenically unsaturated group, or (d) a reactive group having a halogen atom.

3. The electrolyte composition according to claim 1, wherein the additive (2) comprising an ether compound having an ethylene oxide unit is an additive of any of the formulas (iv) to (vii):

wherein each of R4 to R18 is an alkyl group having 1 to 6 carbon atoms, and each of c to r is a number of 0 to 12.

4. The electrolyte composition according to claim 1, wherein the unsaturated group-containing cyclic carbonate (4) is vinylene carbonate or a derivative thereof, or ethylene carbonate having an unsaturated group.

5. The electrolyte composition according to claim 4, wherein vinylene carbonate and the derivative thereof are a compound of the below-mentioned formula (viii-1):

wherein R19 and R20 are hydrogen or an alkyl group having 1 to 6 carbon atoms.

6. The electrolyte composition according to claim 4, wherein the unsaturated group-containing ethylene carbonate is a compound of the below-mentioned formula (viii-2):

wherein R21 is H or an alkyl group having 1 to 6 carbon atoms, R22 is an alkenyl group having 1 to 6 carbon atoms or -CH2OR22' (R22' is an alkenyl group having 1 to 6 carbon atoms).

7. The electrolyte composition according to claim 1, wherein the amount of the cyclic carbonate (4) is from 1 to 100 parts by weight, based on 100 parts by weight of the total of the ether linkage-containing polymer (1), the additive comprising ethylene oxide unit-containing ether compound (2), and the lithium salt compound (3).

8. The electrolyte composition according to claim 1, wherein the ether linkage-containing polymer (I) has a weight-average molecular weight of 10 4 to 10 8.

9. The electrolyte composition according to claim 1, wherein the electrolyte composition comprises the polymer (1) and is produced by impregnating the cyclic carbonate (4) into a crosslinked material comprising the components (1) to (3).

10. The electrolyte composition according to claim 1, wherein the polymer (1) is crosslinked with containing the additive (2) and/or the lithium salt compound (3), or the additive (2) and/or the lithium salt compound (3) are impregnated into the crosslinked material.

11. A battery comprising the electrolyte composition according to anyone of claims 1 to 10, a positive electrode and a negative electrode.

12. The battery according to claim 11, wherein the negative electrode is a lithium metal.