JP2000207934A - Ion conductive high polymer gel electrolyte and solid battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion conductive high polymer gel electrolyte causing no change of a prepared composition by volatilization of solvent, when manufacturing and superior in conductivity at a low temperature. SOLUTION: This electrolyte is high polymer gel electrolyte, containing (i) nonaqueous electrolyte comprising nonaqueous solvent and electrolyte salt and (ii) a high polymer matrix, and it contains at least one kind of cyano-ethyl- ether compound expressed by the general formula, X-(OR)n-O(CH2)m-CN.(In the formula, X indicates 1-10C hydrocarbon radical a fluorine atom substitution 1-10C hydrocarbon radical, and R indicates an 2-4C alkylene radical having 2-4 (m) is 1 or 2 and (n) is an integer of 0-30).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ion-conductive polymer gel electrolyte containing a cyanoethyl ether compound and a solid-state battery using the ion-conductive polymer gel electrolyte.

[0002]

BACKGROUND OF THE INVENTION A positive electrode is a major component of a battery,
A negative electrode and an electrolytic solution are mentioned. Conventionally, a battery container used for such a battery is rigid in order to prevent leakage of the electrolytic solution and a reduction in battery life due to volatilization of the electrolytic solution. Highly sealed and pressure-resistant structure (cylindrical,
(Square type, coin type) are required. In particular, in recent years, batteries of various shapes have been required, and flat, large-area batteries have been developed.

[0003] As such a battery, a solid battery using a solid electrolyte in place of a conventionally used electrolyte has been receiving attention. As solid electrolytes used for such solid state batteries, various ceramics, NASIKO
Inorganic conductive glasses such as N and LISICON, and polymer gel electrolytes comprising a solid solution of a polymer matrix and an electrolyte salt are known.

[0004] However, inorganic conductive glass has a problem that its stability as a material is low and the battery system is limited. On the other hand, the polymer gel electrolyte is excellent in workability, but has problems such as low ionic conductivity.

In order to solve such problems, for example, a polymer gel electrolyte using a polysiloxane (US Pat. No. 5,123,512) or polyphosphazene (US Pat. No. 4,840,856) as a polymer matrix, and a crosslinked polyethylene oxide (US Pat. , 037,712, US5,229,
225, US5,009,97 US5,102,75
2), ethylene oxide-based copolymer (US Pat. No. 4,811)
8,644, JP-A-3-24164), vinyl copolymer (JP-A-7-32081), epoxy resin (US
5,006,431) has been proposed as a polymer gel electrolyte using a polymer matrix.

However, these polymer gel electrolytes have high ionic conductivity in a wide temperature range including a low temperature, and therefore, as a plasticizer, a solvent having a low viscosity and a low boiling point,
For example, a chain ester or a chain carbonate is often used.For this reason, when a polymer matrix is dissolved in a plasticizer or when a monomer containing a plasticizer is polymerized, the solvent used is easily volatilized, There is a problem that it is difficult to produce a gel polymer electrolyte having a desired composition ratio. On the other hand, when the non-aqueous solvent used as the plasticizer is composed of a high-boiling solvent such as ethylene carbonate and / or propylene carbonate, the ionic conductivity at a low temperature is low, and the performance is not necessarily sufficient as a polymer gel electrolyte for batteries. Was not obtained.

Under these circumstances, the present inventors have conducted intensive studies. As a result, the use of a non-aqueous solvent containing a specific cyanoethyl ether compound has particularly high ionic conductivity and a low composition at low temperatures. The inventors have found that a polymer gel electrolyte that is hard to change can be obtained, and have completed the present invention.

[0008]

An object of the present invention is to provide an ion-conductive polymer gel electrolyte which is free from volatilization of the solvent during production and does not change the charge composition, and has excellent conductivity at low temperatures. It is intended to provide a solid battery using a gel.

[0009]

SUMMARY OF THE INVENTION The ion-conductive polymer gel electrolyte according to the present invention is a non-aqueous electrolyte comprising a non-aqueous solvent and an electrolyte salt, and a polymer gel electrolyte containing a polymer matrix. And at least one cyanoethyl ether compound represented by the following general formula [1].

X— (OR) _n —O (CH ₂ ) _m —CN [1] (In the formula [1], X represents a hydrocarbon group having 1 to 10 carbon atoms or a fluorine group having 1 to 10 carbon atoms. It represents an atom-substituted hydrocarbon group, and R represents an alkylene group having 2 to 4 carbon atoms.
M is 1 or 2, and n is an integer of 0 to 30. )

[0011]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described specifically. The ion-conductive polymer gel electrolyte according to the present invention is a non-aqueous electrolyte comprising a non-aqueous solvent and an electrolyte salt, and a polymer matrix containing, as a solvent of the non-aqueous electrolyte, a specific cyanoethyl It is characterized by using an ether compound.

First, each component constituting the ion-conductive polymer gel electrolyte according to the present invention will be described. [Non-Aqueous Electrolyte] Cyanoethyl Ether Compound In the present invention, a compound represented by the following general formula [1] is used as a non-aqueous solvent as a cyanoethyl ether compound.

X— (OR) _n —O (CH ₂ ) _m —CN [1] In the above formula [1], X represents a hydrocarbon group having 1 to 10 carbon atoms or a fluorine atom having 1 to 10 carbon atoms. A substituted hydrocarbon group, specifically, a methyl group (—CH ₃ ), an ethyl group (—CH ₂ CH ₃ ), a propyl group (—CH ₂ CH ₂ C)
H _3), isopropyl group _{(-CH 2 (CH 3) 2} ), n- butyl _{(-CH 2 CH 2 CH 2 CH} 3), an isobutyl group, sec-
Butyl group, tert- butyl group _{(-C (CH 3) 3)} , phenyl group _{(-C 6 H 5), CF} 3 CH 2 groups, CF ₃ groups, CH ₂ FCH
₂ group, is like p-F-C ₆ H ₄ group, a methyl group in this (-CH _3), an ethyl group (-CH ₂ CH ₃₎ are preferred.

In the above formula [1], R represents 2 carbon atoms.
A to 4 hydrocarbon groups, specifically, -CH ₂ CH
_{2 -, - CH 2 CH (} CH 3) -, - CH 2 CH (CH 2 CH 3)
_{-, - CH 2 CH 2 CH} 2 -, - CH 2 CH 2 CH (CH 3)
_{-, - CH 2 CH 2 (} CH 2 OCH 3) - and the like, _{preferably, -CH 2 CH 2 -, -} CH 2 CH (CH 3) - it is.

Further, in the above formula [1], m is 1 or 2, and n is an integer of 0 to 30, preferably 0.
And more preferably an integer of 0 to 3. Such cyanoethyl ether compound represented by the formula _{[1], CH 3 O-} CH 2 CN CH 3 O-CH 2 CH 2 CN CH 3 CH 2 O-CH 2 CH 2 CN C 6 H 5 O- CH ₂ CH ₂ CN

[0016]

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CH ₃ —OCH ₂ CH ₂ —OCH ₂ CH ₂ CN CH ₃ CH ₂ —OCH ₂ CH ₂ —OCH ₂ CH ₂ CN CH ₃ — (OCH ₂ CH ₂ ) ₂ —OCH ₂ CH ₂ CN CH ₃ — _{(OCH 2 CH 2) 10 -OCH} 2 CH 2 CN CH 3 -OCH 2 CH (CH 3) -OCH 2 CH 2 CN CH 3 - (OCH 2 CH (CH 3)) 10 -OCH 2 CH 2 CN CF 3 _{O-CH 2 CH 2 CN CH} 2 FCH 2 O-CH 2 CH 2 CN CF 3 CH 2 O-CH 2 CH 2 CN p-F-C 6 H 4 O-CH 2 CH 2 CN

[0018]

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CF ₃ —OCH ₂ CH ₂ —OCH ₂ CH ₂ CN CH ₂ FCH ₂ —OCH ₂ CH ₂ —OCH ₂ CH ₂ CN CF ₃ CH ₂ —OCH ₂ CH ₂ —OCH ₂ CH ₂ CN CF ₃ CH _{2 - (OCH 2 CH 2) 2} -OCH 2 CH 2 CN CF 3 CH 2 - (OCH 2 CH 2) 10 -OCH 2 CH 2 CN CF 3 CH 2 -OCH 2 CH (CH 3) -OCH 2 CH 2 CN _{CF 3 CH 2 - (OCH 2} CH (CH 3)) 10 -OCH 2 CH 2 C
N and the like.

Among these, a particularly preferred cyanoethyl ether compound is CH ₃ O—CH ₂ CH ₂ CN CH ₃ CH ₂ O—CH ₂ CH ₂ CN CH ₃ CH ₂ —OCH ₂ CH ₂ —OCH ₂ CH ₂ CN is there.

These cyanoethyl ether compounds are
It has a low melting point and is less susceptible to electrochemical oxidation and reduction. In addition, it has a characteristic that the boiling point is high and the viscosity is small as compared with the chain carbonate which is the same chain compound.

The above-mentioned cyanoethyl ether compound can be used alone as a non-aqueous solvent for a non-aqueous electrolyte, but can also be used as a mixed solvent of the above-mentioned cyanoethyl ether compound and another non-aqueous solvent.

As such other non-aqueous solvents, cyclic carbonates and / or chain carbonates are preferable from the viewpoint of improving ionic conductivity. As the cyclic carbonate , a cyclic carbonate containing an alkylene group having 2 to 5 carbon atoms represented by the following general formula [A] is preferably used.

[0024]

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(Wherein, n is an integer of 0 to 3) Specific examples of such a cyclic carbonate include a cyclic carbonate represented by the following formula [2].

[0026]

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Here, R ^a and R ^b may be the same or different from each other, and a hydrogen atom, a linear, branched, or cyclic alkyl group, or part or all of hydrogen is replaced with fluorine, It represents a halogen-substituted alkyl group substituted with at least one of chlorine and bromine. As the linear alkyl group, a linear alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a butyl group is preferable. As the branched alkyl group, a branched alkyl group having 3 to 6 carbon atoms such as an isopropyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group is preferable. As the cyclic alkyl group, a cyclic alkyl group having 5 to 10 carbon atoms such as a cyclopentyl group, a cyclohexyl group, and a 1-methyl-cyclohexyl group is preferable.

Specific examples of the cyclic carbonate represented by the formula [2] include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate,
Examples thereof include 3-butylene carbonate, 1,3-propylene carbonate, 1,3-butylene carbonate, 2,4-pentylene carbonate, 1,3-pentylene carbonate, and vinylene carbonate.

Further, a halogen-substituted cyclic carbonate in which a methyl group such as propylene carbonate or the like has part or all of hydrogen substituted with at least one of fluorine, chlorine and bromine can be used.

As the cyclic carbonic acid ester, in addition to the 5-membered ring compound represented by the above formula [2], a 6-membered ring compound wherein n in the above formula [A] is 1 is preferably used. Can be.

Of these cyclic carbonates,
Ethylene carbonate and propylene carbonate are preferably used. In addition, such a cyclic carbonate is 2
A mixture of more than one species can be used.

The chain carbonate or the chain carbonate has 1 to 10 carbon atoms.
A chain carbonate compound containing a hydrocarbon group is preferably used. Examples of such a chain carbonate include carbonates represented by the following general formula [3].

[0033]

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In the formula, R ^c and R ^d may be the same or different from each other, and a part or all of a linear, branched or cyclic alkyl group or hydrogen may be at least one of fluorine, chlorine and bromine. It is a halogen-substituted alkyl group substituted with one kind.

Examples of the linear alkyl group include those having 1 to 4 carbon atoms such as methyl, ethyl, propyl and butyl.
Are preferred. As a branched alkyl group, an isopropyl group, an isobutyl group, a sec-butyl group,
A branched alkyl group having 3 to 10 carbon atoms such as a tert-butyl group is preferred. As the cyclic alkyl group, a cyclic alkyl group having 5 to 10 carbon atoms such as a cyclopentyl group, a cyclohexyl group, and a 1-methyl-cyclohexyl group is preferable.

Specific examples of such a chain carbonate include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, dibutyl carbonate, diisopropyl carbonate, methyl ethyl carbonate and the like.

Among such chain carbonates, chain carbonates containing a hydrocarbon group having 1 to 5 carbon atoms are preferable, and dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate are particularly preferable.

Solvent Composition of Nonaqueous Solvent In the present invention, in order for the nonaqueous electrolyte to have a low viscosity at a low temperature, exhibit a high ionic conductivity and a high boiling point, the above formula [ 1] is 0.1 to 100% by weight, preferably 1 to 90% by weight.
%, More preferably 20-70% by weight.

The cyclic carbonate and / or chain carbonate is contained in a nonaqueous solvent in an amount of 0 to 99.9% by weight,
More preferably 10-99% by weight, most preferably 30-80%
Desirably, it is included in an amount of weight percent.

The non-aqueous electrolyte used in the present invention may contain, as a non-aqueous solvent, other solvents in addition to those described above. Specifically, γ-butyrolactone, γ-valerolactone , 3-methyl-γ-butyrolactone, 2-methyl-γ-
Cyclic esters such as butyrolactone, chain esters such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, methyl butyrate, methyl valerate, 1,4-dioxane, 1,3-dioxolan, and tetrahydrofuran , 2-methyltetrahydrofuran, 3-methyl
Cyclic ethers such as -1,3-dioxolan, 2-methyl-1,3-dioxolan, 1,2-dimethoxyethane, 1,2-diethoxyethane, diethyl ether, dimethyl ether, methyl ethyl ether, dipropyl ether, etc. Examples thereof include sulfur-containing compounds such as chain ether, sulfolane, and dimethyl sulfate, and phosphorus-containing compounds such as trimethylphosphoric acid and triethylphosphoric acid.

These solvents can be used alone or in combination of two or more. Electrolyte The electrolyte used in the present invention can be used without any particular limitation as long as it is used as an electrolyte for a non-aqueous electrolyte. Specifically, LiP
_{F 6, LiBF 4, LiClO 4} , LiAsF 6, LiAlCl 6,
Li ₂ SiF ₆ , LiOSO ₂ R ¹ ,

[0042]

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Wherein R ^{1 to} R ⁸ may be the same or different and are perfluoroalkyl groups having 1 to 6 carbon atoms, and the like. Examples thereof include alkali metal salts substituted with other alkali metals. These can be used alone or in combination of two or more.

Of these, in particular, LiPF ₆ and LiB
F ₄ , LiOSO ₂ R ¹ ,

[0045]

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Is preferred. Such electrolytes are usually
0.1-3.0 mol / l, preferably 0.5-2.0
It is desirable that the compound is contained in the non-aqueous electrolyte at a concentration of mol / liter.

[Polymer Matrix] As the polymer matrix, thermoplastic polymers such as polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, polyethylene oxide and polypropylene oxide, or ethyleneoxy chains are used. Examples include a polysiloxane having a side chain or a crosslinked polymer having an ethylene oxide chain in a side chain or a main chain, or a crosslinked polymer such as urethane, acryl, or epoxy.

The polymer matrix contains (a) a structural unit derived from at least one acrylate selected from acrylates represented by the following general formulas (I) and (II). An acrylate polymer matrix can also be used. Specific examples of such an acrylate polymer matrix include homopolymers or copolymers of acrylates represented by the following general formula (I) or (II).

[0049]

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(Wherein R ¹ , R ² and R ^{2 ′} may be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is a carbon atom or a carbon atom. Number one
And n is an integer of 1 to 100. )

[0051]

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(Wherein, R ^{4 to} R ⁹ may be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and p, q and r are the same or different. May be an integer of 1 to 100.) Note that the acrylate represented by the formula (I) includes
2-methacryloyloxy-2-methylethyl methyl carbonate, 2 (2-methacryloyloxy-2-methylethoxy)
Isopropyl methyl carbonate, 2 (2-methacryloyloxy 2-methylethoxy) 2-methylethyl methyl carbonate, 2 (2-methacryloyloxy isopropoxy) 2-
Methyl ethyl methyl carbonate, 2-methacryloyloxyethyl methyl carbonate, 2 (2-methacryloyloxyethoxy) ethyl methyl carbonate, 2-methacryloyloxyethyl ethyl carbonate, 2 (2-methacryloyloxyethoxy) ethyl ethyl carbonate, 2-
Methacryloyloxyisopropylmethyl carbonate, 2 (2-methacryloyloxyisopropoxy) isopropylmethyl carbonate, 2-methacryloyloxyisopropylethyl carbonate, 2 (2-methacryloyloxyisopropoxy) isopropylethyl carbonate, 2-acryloyloxyethylmethyl carbonate,
2 (2-acryloyloxyethoxy) ethyl methyl carbonate, 2-acryloyloxyethyl ethyl carbonate, 2 (2-acryloyloxyethoxy) ethyl ethyl carbonate, 2-acryloyloxyisopropylmethyl carbonate, 2 (2-acryloyloxyisopropoxy) isopropyl Examples include methyl carbonate, 2-acryloyloxyisopropylethyl carbonate, and 2 (2-acryloyloxyisopropoxy) isopropylethyl carbonate.

The acrylate represented by the formula (II) includes di (2-methacryloyloxyethyl) carbonate, di (2-acryloyloxyethyl) carbonate,
Di (2 (2-methacryloyloxyethoxy) ethyl) carbonate, di (2 (2-acryloyloxyethoxy) ethyl)
Carbonate, di (2-methacryloyloxyisopropyl) carbonate, di (2-acryloyloxyisopropyl) carbonate, di (2 (2-methacryloyloxyisopropoxy) isopropyl) carbonate, di (2 (2-acryloyloxyisopropoxy) isopropyl) Carbonate, 2-methacryloyloxyethyl (2 (2-methacryloyloxyethoxy) ethyl) carbonate, 2-acryloyloxyethyl (2 (2-acryloyloxyethoxy) ethyl) carbonate, di (methacryloyl tri (oxyethylene)) carbonate, di (Acryloyltri (oxyethylene)) carbonate, di (methacryloyltetra (oxyethylene)) carbonate, di (acryloyltetra (oxyethylene)) carbonate and the like.

Furthermore, in the present invention, as the polymer matrix, [A] (i) a diol compound, (ii) a polyhydric alcohol having a valence of 3 or more, and an alkylene oxide added to a polyhydric alcohol having a valence of 3 or more are used. A structure derived from an esterified product of (B) (meth) acrylic acid and a polycarbonate polyol obtained by polycondensing a polyol compound selected from a polyhydric alcohol adduct and (iii) a carbonyl group-containing compound. Polycarbonate (meth) acrylate polymers containing units can also be used.

The polycarbonate polyol has a carbonate bond and an alkylene oxide chain in the molecule and has a hydroxyl group at the molecular terminal. In this polycarbonate polyol, depending on the molecular structure,
There are (i) linear polycarbonate polyols and (ii) cross-linked polycarbonate polyols.

(I) The straight-chain polycarbonate diol is obtained by polycondensing a diol compound and a carbonyl group-containing compound. Specific examples of the diol compound include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, and 1,8-octane. Diol, 1,3-bis (2-hydroxyethoxy) benzene, 1,4-cyclohexanediol, 1,4
-Cyclohexanedimethanol. These may be used alone or in combination.

The carbonyl group-containing compound is preferably a diester carbonate, phosgene or chloroformate. Examples of the diester carbonate include diester carbonates such as dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, diphenyl carbonate, ethylene carbonate and propylene carbonate. Can be Examples of the chloroformate include methyl chloroformate, ethyl chloroformate, phenyl chloroformate and the like.

Such a linear polycarbonate polyol can be obtained by polycondensing the above-mentioned diol compound and a carbonyl group-containing compound by a known method. At this time, the carbonyl group-containing compound is
The amount is preferably 0.2 to 2 equivalents, and more preferably 0.5 to 1.5 equivalents, to the hydroxyl group in the diol compound.

The (ii) cross-linked polycarbonate polyol is obtained by polycondensing a diol compound, a polyol compound, and a carbonyl group-containing compound.
Examples of the diol compound and the carbonyl group-containing compound include the same compounds as described above. Examples of the polyol compound include compounds selected from trihydric or higher polyhydric alcohols and polyhydric alcohol adducts.
Examples of the trihydric or higher polyhydric alcohol include trimethylolpropane, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, glycerin, sorbitol and the like. The polyhydric alcohol adduct is obtained by adding an alkylene oxide to the above-mentioned trihydric or higher polyhydric alcohol.

In the present invention, the polyol compound is preferably a trihydric or higher polyhydric alcohol to which ethylene oxide or propylene oxide is added in the same number or more, preferably 1 to 10 times, as the number of hydroxyl groups. As the polyhydric alcohol having a valency or higher, trimethylolpropane or pentaerythritol is preferable.

When such a polyol compound is explained by taking a trimethylolpropane adduct as an example, the following compounds are exemplified.

[0062]

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Such polyol compounds may be used as a mixture of two or more kinds. The crosslinked polycarbonate polyol can be obtained by polycondensing the diol compound, the polyol compound, and the carbonyl group-containing compound as described above by a known method. At this time, the charged molar ratio of the diol compound and the polyol compound is
It is desirable to be in the range of 50:50 to 99: 1. The carbonyl group-containing compound is used in an amount of preferably 0.2 to 2 equivalents, more preferably 0.5 to 1.5 equivalents, based on all hydroxyl groups in the diol compound and the polyol compound.

In the crosslinked polycarbonate polyol, when the diol compound and the carbonyl group-containing compound are polycondensed, the polyol compound is contained, so that the polycondensation proceeds three-dimensionally to obtain a crosslinked polycarbonate polyol.

The molecular weight of the linear or crosslinked polycarbonate polyol used in the present invention is preferably in the range of 300 to 100,000 in terms of weight average molecular weight in terms of polystyrene by GPC.

Such a polycarbonate polyol and
Condensation of (meth) acrylic acid halide in the presence of a base, or condensation of polycarbonate polyol and (meth) acrylic anhydride in the presence of a catalyst, and furthermore, an acid catalyst of polycarbonate polyol and (meth) acrylic acid The above-mentioned polycarbonate (meth) acrylate polymer can be obtained by condensation in the presence.

Further, as the polymer matrix, for example, a homopolymer or copolymer of a monofunctional or polyfunctional (meth) acrylate monomer or prepolymer may be used. In addition, (meth) acrylate in this specification means acrylate or methacrylate.

Examples of the monofunctional (meth) acrylate include alkyl (meth) acrylates (eg, methyl (meth) acrylate, butyl (meth) acrylate, trifluoro (meth) acrylate), alicyclic (meth) acrylate and alkoxyalkyl ( (The number of carbon atoms of the alkoxy group is preferably an integer of 1 to 4.) (meth) acrylate [methoxyethyl acrylate, ethoxyethyl acrylate, ethoxybutyl acrylate] is exemplified. Specific examples of the (meth) acrylate other than the above include, for example, (poly) ethylene glycol (meth) acrylate [methyl ethylene glycol (meth) acrylate, ethyl ethylene glycol (meth) acrylate, methyl diethylene glycol (meth) acrylate, ethyl diethylene glycol (Meth) acrylate, methyltriethylene glycol (meth) acrylate, ethyltetraethylene glycol (meth) acrylate, etc.],
(Poly) propylene glycol (meth) acrylate [ethyl propylene glycol acrylate, methyldipropylene glycol (meth) acrylate] and the like.

These (meth) acrylates may contain a heterocyclic group, and the heterocyclic group is a heterocyclic residue containing a hetero atom such as oxygen, nitrogen or sulfur.
The type of the heterocyclic group contained in the (meth) acrylate is not particularly limited. For example, furfuryl (meth) acrylate having a furfuryl group, a tetrahydrofurfuryl group, or the like, tetrahydrofurfuryl (meth) acrylate, , An alkylene glycol (meth) acrylate having a furfuryl group, a tetrahydrofurfuryl group, etc. [furfurylethylene glycol (meth) acrylate, tetrahydrofurfurylethylene glycol (meth) acrylate, etc.]. Other (meth) acrylates having a heterocyclic group include furfurylethylene glycol (meth) acrylate, tetrahydrofurfurylethylene glycol (meth) acrylate, furfurylpropolene glycol (meth) acrylate, and tetrahydrofurfurylpropylene glycol (meth) acrylate. An alkylene glycol acrylate having a furfuryl group or a tetrahydrofurfuryl group such as an acrylate is exemplified.

The above (meth) acrylate compounds may be used alone or in combination of two or more. The use ratio of the (meth) acrylate compound is usually 50% by weight or less, preferably 5 to 40% by weight, more preferably 10% by weight with respect to the non-aqueous electrolyte.
３０30% by weight.

Examples of the polyfunctional (meth) acrylate compound include a monomer or a prepolymer having two or more (meth) acryloyl groups. Examples of the polyfunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and EO-modified trimethylolpropanetriene. Acrylate, PO-modified trimethylolpropane triacrylate, butanediol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like can be given.

In order to form a crosslinked polymer matrix, a combination of a monofunctional monomer and a polyfunctional monomer is particularly desirable. When a monofunctional monomer and a polyfunctional monomer are used in combination, when the polyfunctional monomer is a polyfunctional (meth) acrylate, the amount of the polyfunctional (meth) acrylate compound is 4 to the non-aqueous electrolyte. % By weight or less is preferred.

The compounds represented by the general formulas (I) and (I)
Acrylic esters, polycarbonate polyols, methacrylic halides, methacrylic anhydrides and the like represented by I) can also be used as the polymerizable compound.

Ion Conducting Polymer Gel Electrolyte The ion conducting polymer gel electrolyte according to the present invention is a gel polymer solid electrolyte.

The composition ratio between the non-aqueous electrolyte and the polymer matrix contained in the polymer gel electrolyte is not particularly limited as long as the polymer electrolyte is in a gel-like composition ratio. In particular, 200 parts by weight or more, preferably 400 parts by weight of the non-aqueous electrolyte is added to 100 parts by weight of the polymer matrix.
It is desirable that it be contained in an amount of at least part by weight, more preferably 400 to 1,000 parts by weight.

The polymer gel electrolyte according to the present invention can be prepared by impregnating the above-described polymer matrix with the above-mentioned non-aqueous electrolyte. The gel polymer electrolyte according to the present invention can be produced by dissolving a polymerizable compound such as a monomer or a prepolymer that forms the polymer matrix in a non-aqueous electrolyte and causing a polymerization reaction.

The polymerizable compound to be used is not particularly limited as long as it forms the above-mentioned polymer matrix, and in particular, a polymer is obtained by causing a polymerization reaction such as thermal polymerization and active light polymerization. Things are desirable.

The polymerization of the polymerizable compound is usually carried out in the presence of a photopolymerization initiator or a thermal polymerization initiator. Examples of the photopolymerization initiator include carbonyl compounds [benzoins (benzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, α-phenylbenzoin, etc.), anthraquinones (anthraquinone, methylanthraquinone, chloranthraquinone, etc.). ), Other compounds (benzyldiacetyl, acetophenone, benzophenone, methylbenzoylformate, etc.)], sulfur compounds (diphenylsulfide, dithiocarbamate, etc.), polycondensed ring hydrocarbon halides (α-chloromethylnaphthalene, etc.), Pigments (acrylic flavin, fluorescein, etc.), metal salts (iron chloride, silver chloride, etc.), onium salts (p-methoxybenzenediazonium, hexafluorophosphate) , Diphenyliodonium, triphenylsulfonium, etc.). These can be used alone or as a mixture of two or more. Of these, carbonyl compounds, sulfur compounds,
Onium salts are preferably used.

Examples of the thermal polymerization initiator include azobisisobutyronirolyl, azobisisovaleronitrile, benzoyl peroxide, lauroyl peroxide, ethyl methyl ketone peroxide, and bis- (4-t-butylcyclohexyl). Peroxycarbonate, diisopropyl peroxycarbonate and the like can be mentioned.

In conducting the polymerization, if necessary, a sensitizer,
Storage stabilizers may be included. As sensitizers, urea, nitrile compounds (N, Np-aminobenzonitrile),
Phosphorus compounds (such as tri-n-butylphosphine) are preferred, and quaternary ammonium chloride, benzothiazole, and hydroquinone are preferred as storage stabilizers.
The amount of the polymerization initiator to be used is generally 0.1 to 10% by weight, preferably 0.5 to 7% by weight, based on all the polymerizable compounds. The amount of the sensitizer and storage stabilizer used is the total amount of the polymerizable compound 1
It is preferably 0.1 to 5 parts by weight based on 00 parts by weight.

The polymer gel electrolyte according to the present invention is prepared by injecting a non-aqueous electrolyte containing the above-mentioned polymerizable compound for forming a matrix into a closed container, and then heat or reacting the polymer with the lower polymerization initiator in the presence of the lower polymerization initiator. It can be produced by polymerizing with a light beam. Actinic rays are usually light, ultraviolet,
Electron beams, X-rays and the like can be used.

Further, a non-aqueous electrolytic solution in which a polymerizable compound for forming a matrix is dissolved may be used, for example, for film, metal, glass,
After coating on a support such as an electrode, it may be polymerized by heat or actinic rays. According to such a method, it is possible to obtain a polymer gel electrolyte which has previously been composited (integrated) with a part of a battery component such as a film or a sheet, or an electrode or a separator. In particular, in a solid-state battery described later, it is desirable that the polymer gel electrolyte is integrated with the battery component.

[Solid Battery Containing Ion-Conducting Polymer Gel Electrolyte] Next, a solid-state battery using the ion-conducting polymer gel electrolyte of the present invention as a battery electrolyte will be described in detail. Generally, a battery includes a positive electrode made of a positive electrode active material, a negative electrode made of a negative electrode active material, and an electrolyte.

By using the polymer gel electrolyte of the present invention as an electrolyte in this battery, it is possible to obtain a solid battery having excellent characteristics as compared with a conventional battery. The positive electrode active material used in the solid state battery according to the present invention is T
iS ₂ , MoS ₂ , Co ₂ S ₅ , V ₂ O ₅ , MnO ₂ , CoO ₂
As transition metal oxides, transition metal chalcogen compounds and composites thereof with Li (Li composite oxide),
LiMnO ₂ , LiMn ₂ O ₄ , LiCoO ₂ , LiNiO
₂ , LiCo _x Ni _1-x O ₂ (0 <x <1), LiMn _{2-a
X a O 4, LiMn 2-} ab X a Y b O 4 (0 <a <2,0 <b
<2, 0 <a + b <2). The conductive material added to secure the conductivity of the positive electrode may be a one-dimensional graphite compound, which is a thermal polymer of an organic substance, carbon fluoride, graphite, or an electric conductivity of 10 ⁻² S / cm or more. Examples of the conductive polymer include polymers such as polyaniline, polypyrrole, polyazulene, polyphenylene, polyacetylene, polyphthalocyanine, poly-3-methylthiophene, polypyridine, and polydiphenylbenzidine, and derivatives thereof.

The negative electrode active material used in the solid state battery of the present invention includes metal negative electrodes such as lithium, lithium aluminum alloy, lithium tin alloy, and lithium magnesium alloy, and carbon (including graphite-based and non-graphite-based). Carbon materials capable of doping and undoping lithium ions, such as carbon boron substitutes (BC ₂ N), tin oxide capable of doping and undoping lithium ions, silicon capable of doping and undoping lithium ions, Examples include lithium ions.

Examples of the carbon material include graphite, pitch coke, synthetic polymers and calcined products of natural polymers. Particularly, synthetic polymers such as phenol and polyimide and natural polymers are reduced at 400 to 800 ° C. in a reducing atmosphere. Insulating or semiconducting carbon, coal, pitch, synthetic polymer or natural polymer obtained by firing under
Conductive carbon, coke, pitch, synthetic polymer and natural polymer obtained by firing in a reducing atmosphere at 0 to 1300 ° C.
Those obtained by calcination in a reducing atmosphere at a temperature of 0 ° C. or higher, and natural graphite-based carbon bodies are preferably used.

As the positive electrode current collector used in the present invention, for example, a metal sheet such as stainless steel, gold, platinum, nickel, aluminum, molybdenum, titanium, etc., a metal foil, a metal net, a punching metal, an expanded metal, or a metal plating Nets and nonwoven fabrics made of fibers, metal-deposited wires, metal-containing synthetic fibers, and the like can be given. Among these positive electrode current collectors, it is particularly desirable to use aluminum, stainless steel, and titanium in terms of electric conductivity, chemical stability, electrochemical stability, economy, and workability.

The ionic conductive polymer gel electrolyte of the present invention as described above can be used as it is as a battery membrane, but it is used by further dispersing a filler or complexing with a porous membrane (separator). You can also. Examples of the separator include a glass fiber, a filter, a nonwoven fabric filter made of a polymer fiber such as polyester, Teflon, polyflon, polypropylene, and polyethylene, and a nonwoven fabric filter in which the glass fiber and the polymer fiber are mixed.

When the polymer gel electrolyte of the present invention is applied to a battery, in order to make the electrolysis between the electrodes uniform, to improve the strength, and to improve the reliability of the obtained battery, a separator such as a separator is used by the above-mentioned method. It may be combined (integrated) with the battery component. In particular, in the case of a secondary battery, it is desirable that the battery is combined (integrated) with the separator.

Specifically, the battery is obtained by impregnating the above-mentioned components for forming the ion-conductive gel polymer electrolyte, that is, the non-aqueous electrolyte and the polymerizable compound for forming the polymer matrix, into the battery constituent members such as electrodes and diaphragms. By polymerizing the polymerizable compound by polymerization means such as heating or irradiation with actinic rays,
Allow to gel. In addition, the integration of the battery component and the ion-conductive gel polymer electrolyte can be performed for each battery.

As in the present invention, since the gelled polymer electrolyte contains the cyanoethyl ether compound, the solvent is less volatilized at the time of gelation, so that a polymer gel electrolyte having a charged composition is maintained. It is possible to obtain a battery which is easy and has excellent battery characteristics, especially having high ion conductivity at low temperature.

[0092]

The ionic conductive polymer gel electrolyte of the present invention has high ionic conductivity and is electrochemically stable. For example, electrochemical devices such as primary batteries, secondary batteries, capacitors, and electrochromic display devices. , Medical actuators and the like.

The ion-conductive polymer gel electrolyte of the present invention uses a specific cyanoethyl ether as the non-aqueous solvent, so that the solvent does not evaporate during the production and the charged composition does not change. Moreover, it has excellent conductivity at low temperatures.

[0094]

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[0095]

Example 1 In a non-aqueous solvent obtained by mixing ethylene carbonate (EC) and ethylene glycol methyl cyanoether (1CE-MOH) at a volume ratio of 1: 1, LiPF ₆ was adjusted to 1 mol / liter. To prepare a non-aqueous electrolyte.

20 parts by weight of di (methacryloyloxyethyl) carbonate was added to 80 parts by weight of the prepared non-aqueous electrolyte, and 2,2-azobis (isobutyric acid) dimethyl ester was added as a thermal polymerization initiator to di ( It was added so as to be 4 mol% with respect to (methacryloyloxyethyl) carbonate to prepare a mixed solution for preparing a polymer gel electrolyte.

This mixed solution for preparing a polymer gel electrolyte was poured into a Jenny cell (Pt electrode, electrode area: 1 cm ² , distance between electrodes: 1 cm) and heated at 70 ° C. for 1 hour in a sealed state to gel. .

With respect to the polymer gel electrolyte thus obtained, -20 ° C., -10 ° C., 0 ° C., 10 ° C., 20 ° C., 25 ° C.
The ionic conductivity at ℃ was measured. Table 1 shows the results.

[0099]

[Table 1]

As is clear from Table 1, the ionic conductivity of Example 1 containing the specific cyanoethyl ether compound was high at any measurement temperature.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 6/22 H01M 6/22 C // H01M 10/40 10/40 B F term (Reference) 4J002 BG041 BG051 BG071 CG011 CH051 CH052 DG018 DH008 DK008 EH007 EL067 ET006 EV248 EV268 FD118 GQ00 HA05 5G301 CA08 CA16 CA30 CD01 5H024 AA02 AA12 EE09 FF14 FF15 FF18 FF19 FF21 FF32 FF36 5H029 AJ04 AM03 A0702 A14

Claims (6)

[Claims] 1. A polymer gel electrolyte comprising: (i) a non-aqueous electrolyte comprising a non-aqueous solvent and an electrolyte salt; and (ii) a polymer gel electrolyte, wherein at least one type of non-aqueous solvent is used. An ion-conductive polymer gel electrolyte comprising a cyanoethyl ether compound represented by the following general formula [1]. X— (OR) _n —O (CH ₂ ) _m —CN [1] (In the formula [1], X represents a hydrocarbon group having 1 to 10 carbon atoms or a fluorine-substituted carbon group having 1 to 10 carbon atoms. R represents a hydrogen group, and R represents an alkylene group having 2 to 4 carbon atoms.
M is 1 or 2, and n is an integer of 0 to 30. ) 2. The ion according to claim 1, wherein the non-aqueous solvent contains a cyclic carbonate and / or a chain carbonate together with the cyanoethyl ether compound represented by the general formula [1]. Conductive polymer gel electrolyte. 3. The cyclic carbonate has 2 carbon atoms.
The cyclic carbonate compound containing an alkylene group of from 1 to 5, wherein the chain carbonate is a carbonate compound containing a hydrocarbon group having from 1 to 10 carbon atoms. Ion conductive polymer gel electrolyte. 4. The electrolyte according to claim 1, wherein the electrolyte is LiPF ₆ , LiBF ₄ , LiClO.
₄ , LiOSO ₂ R ¹ , (Wherein, R ^{1 to} R ⁸ may be the same or different from each other and are perfluoroalkyl groups having 1 to 6 carbon atoms). The ion-conductive polymer gel electrolyte according to claim 1. 5. The polymer matrix according to 100 parts by weight,
The ion-conductive polymer gel electrolyte according to any one of claims 1 to 4, comprising at least 200 parts by weight of the non-aqueous electrolyte. 6. A solid battery comprising the ion-conductive polymer gel electrolyte according to claim 1.