JPH10177814A - Ion conductive high molecular gel electrolyte and solid battery including high molecular gel electrolyte - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable any battery internal short circuit to be prevented without using any diaphragm by making halogen substitution non-annular ester carbonate and/or halogen substation annular ester carbonate having a specific relative permittivity more than a specific value to be included as a solvent of non- aqueous electrolyte of an ion conductive high molecular gel electrolyte consisting of high molecular matrix, non-aqueous electrolyte and electrolyte salt. SOLUTION: Halogen substitute non-annular ester carbonate of more than specific transmittivity 4.0 shown in a formula I and/or halogen substitute annular ester carbonate shown in a formula II is used. In the formulae, R<1> , R<2> stand for halogen substitute or non-substitute alkyl group H, halogen; R<3> , R<4> stand for halogen substitute or non-substitute alkyl group H, halogen, Methyl-2- chloroethyl ester carbonate and fluoromethylethylene carbonate are shown in form of examples. By means of halogen substitute ester carbonate, particularly ion conductivity elastic modules, solvent holding rate and low temperature ion conductivity etc., are improved and also a frame receptivity is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel gel electrolyte and a solid-state battery using the gel electrolyte.

[0002]

2. Description of the Related Art The main components of a battery include a positive electrode, a negative electrode, and an electrolytic solution. Conventionally, a battery container is rigid and hermetically sealed in order to prevent leakage of the electrolytic solution and a reduction in battery life due to volatilization of the electrolytic solution. There is a demand for a structure (cylindrical, square, coin type) that is high in pressure resistance and excellent in pressure resistance. In particular, batteries have recently been required to have various shapes, and flat and large-area batteries have been developed. Solid batteries are being studied as such batteries. As the solid electrolyte in the solid-state battery, various ceramics, inorganic conductive glasses such as NASIKON and LISICON, and a polymer solid electrolyte comprising a solid solution of a polymer matrix and an electrolyte salt are being studied. However, inorganic electrolytes have problems such as low stability as a material and limited battery system.In addition, solid polymer electrolytes are excellent in workability, but have low ionic conductivity and diaphragm strength. Problems such as low are pointed out. In order to solve these problems, this polymer solid electrolyte includes, in addition to a polymer solid electrolyte using polysiloxane (US Pat. No. 5,123,512) and polyphosphazene (US Pat. No. 4,840,856) as a polymer matrix, polyethylene oxide. Crosslinked products (US 5,037,712, US 5,229,
225, US5,009,970, US5,102,7
52), ethylene oxide copolymer (US Pat. No. 4,81)
8,644, JP-A-3-24164), vinyl copolymer (JP-A-7-320798), epoxy resin (US
No. 5,006,431) is disclosed as a polymer gel electrolyte, but sufficient performance as a polymer solid electrolyte for batteries is obtained in terms of ionic conductivity, film strength, stability and the like. Not been.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems found in conventional solid electrolytes using a polymer as a matrix, and has a high ion conductivity and a sufficient solid strength for a battery. The present invention relates to a conductive polymer gel electrolyte, and by using the polymer gel electrolyte, to provide a highly reliable solid battery excellent in prevention of short circuit inside the battery without using a diaphragm. With the goal.

[0004]

A feature of the present invention is that an ion-conductive polymer gel electrolyte comprising a polymer matrix, a solvent and an electrolyte salt contains at least one halogen-substituted carbonate in a solvent of a non-aqueous electrolyte. It is to use what was let. When a non-cyclic carbonate is contained as a solvent in the non-aqueous electrolyte of the polymer gel electrolyte, the elastic modulus tends to be low as a solid battery electrolyte, and the solvent has a problem of low holding power. . The present inventors have conducted intensive studies on the above problems, and as a result, by using at least one halogen-substituted carbonate as a solvent of the non-aqueous electrolyte, the elastic modulus of the solid electrolyte was improved without lowering the ionic conductivity. The present invention has been found to be able to improve the holding power of the solvent and make the composition flame-retardant, and have reached the present invention. Hereinafter, the configuration of the present invention will be described in detail. The polymer gel electrolyte of the present invention comprises a homogeneous viscoelastic body composed entirely of a polymer matrix, a solvent, and an electrolyte salt. As the halogen-substituted acyclic carbonate used in the present invention, those having a relative dielectric constant of 4.0 or more are preferable because the ionic conductivity of the polymer gel electrolyte can be improved.

[0005] Examples of the halogen-substituted acyclic carbonate used in the present invention include those represented by the following general formulas [I] and / or [II].

Embedded image (In the formula, R ¹ and R ² represent a halogen-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, hydrogen, or halogen.
^At least ^one of R ¹ and R ² always has at least one halogen. Also, even if R ¹ and R ² are the same,
Also, they may be different. In the formula [I], R ¹ and R ^{2 each} have 1 carbon atom.
In the case of an unsubstituted alkyl group of (1) to (4), a methyl group, an ethyl group and the like are preferable. In the case of a halogen-substituted alkyl group, a chloromethyl group, a 2-chloroethyl group, a dichloromethyl group, a 2,2-dichloroethyl group, a trichloromethyl group, a 2,2,2-trichloroethyl group, a pentachloroethyl group 2,2,3,3,3-pentachloropropyl group, heptachloropropyl group, 2,2,3,3,4
4,4-heptachlorobutyl group, fluoromethyl group, 2
-Fluoroethyl group, difluoromethyl group, 2,2-difluoroethyl group, trifluoromethyl group, 2,2,2
-Trifluoroethyl group, pentafluoroethyl group,
2,2,3,3,3-pentafluoropropyl group, bromomethyl group, 2-bromoethyl group, dibromomethyl group,
2,2-dibromoethyl group, tribromomethyl group, 2,
2,2-tribromoethyl group, iodomethyl group, 2-
Those in which halogen is substituted at the 2 or more position such as an iodoethyl group are preferred. Examples of the halogen element include fluorine, chlorine, bromine, and iodine. Particularly, those substituted with a fluorine atom can improve cycle characteristics.

The halogen-substituted cyclic carbonate used in the present invention includes, for example, those represented by the following general formula [II].

Embedded image (Wherein, R ³ and R ⁴ represent a halogen-substituted or unsubstituted alkyl group having 1 to 2 carbon atoms, hydrogen, or halogen.
^At least one halogen is always present in at least one of ³ and R ⁴ . Also, even if R ³ and R ⁴ are the same,
Also, they may be different. In the formula [II], R ³ and R ^{4 each} have 1 to 1 carbon atoms.
In the case of two unsubstituted alkyl groups, a methyl group is preferred.
In the case of a halogen-substituted alkyl group, chloromethyl, dichloromethyl, trichloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl, bromomethyl, dibromomethyl, tribromomethyl, iodomethyl, etc. Preferred are alkyl groups substituted with one or more halogen. Examples of the halogen element include fluorine, chlorine, bromine, and iodine. Particularly, a fluorine-substituted element can improve cycle characteristics.

In both the case of using the compound represented by the formula [I] and the case of using the compound represented by the formula [II], the halogen-substituted carbonate may be used alone or in combination of two or more. . The halogen-substituted acyclic carbonate represented by the formula [I] and the halogen-substituted cyclic carbonate represented by the formula [II] may be used as a mixture thereof. Also in this case, each halogen-substituted carbonate may be used alone or in combination of two or more. For improving the ionic conductivity, a halogen-substituted acyclic carbonate represented by the above formula [I] is particularly preferable.

The halogen-substituted acyclic carbonate having a relative dielectric constant of 4.0 or more includes methyl-2-chloroethyl carbonate, methyl-2,2,2-trichloroethyl carbonate, methyl-2,2,2-carbonate. Trifluoroethyl carbonate, di (2,2,2-trifluoroethyl)
Carbonic ester, methyl-2,2,3,3,3-pentafluoropropyl carbonate and the like are exemplified. The halogen-substituted acyclic carbonate used in the present invention has a relative dielectric constant of 6.0 or more, more preferably 7.0 or more. Examples of those having a relative dielectric constant of 6.0 or more and less than 7.0 include methyl-2-chloroethyl carbonate, methyl-2,2,3,3,3-pentafluoropropyl carbonate, and the like. Examples of those having a relative dielectric constant of 7.0 or more include methyl-2,2,2-trifluoroethyl carbonate and di (2,2,2-trifluoroethyl) carbonate.

As the halogen-substituted cyclic carbonate used in the present invention, any of those having a relative dielectric constant of 4 or more can be used. Examples include fluoromethylethylene carbonate represented by the following formula [III], difluoromethylethylene carbonate represented by the following formula [IV], trifluoromethylethylene carbonate represented by the following formula [V], and the like. Other examples include fluoroethylene carbonate, chloroethylene carbonate, bromoethylene carbonate, iodoethylene carbonate, tribromoethylene carbonate, triiodoethylene carbonate, trichloroethylene carbonate, trichloromethylethylene carbonate, tribromomethylethylene carbonate, triiodomethylethylene carbonate, and the like. Can be

Embedded image

In the present invention, the use of the halogen-substituted carbonic acid ester makes it possible to obtain a gel electrolyte having particularly improved ionic conductivity, elastic modulus, solvent retention, low-temperature ionic conductivity, and the like. A flammable gel electrolyte can also be obtained. In the present invention, the halogen-substituted carbonic acid ester may contain a cyclic carbonic acid ester as a solvent constituting another electrolytic solution. Examples of the cyclic carbonic acid ester to be contained include ethylene carbonate (EC) and propylene carbonate (PC). ), Butylene carbonate (BC) and the like. Other solvents include dimethyl carbonate, diethyl carbonate, γ-butyl lactone, sulfolane, dioxolan, tetrahydrofuran, 2-methyltetrahydrofuran, methyl ethyl carbonate, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane In addition, methyl glyme, methyl triglyme, methyl tetraglyme, ethyl glyme, ethyl diglyme, butyl diglyme, and the like, are not limited thereto, and these solvents may be used alone or as a mixture of two or more. May be used. Among the above cyclic carbonates, cyclic carbonates such as EC and PC are particularly preferable. The mixing ratio of the halogen-substituted acyclic carbonate in the constituent solvent of these non-aqueous electrolytes is preferably 5 to 80% by volume, more preferably 20 to 70% by volume. Especially 30-5
0% by volume is preferred. The mixing ratio of the halogen-substituted cyclic carbonate in the constituent solvent is preferably 20 to 95% by volume, more preferably 30 to 80% by volume, and particularly preferably 50 to 7% by volume.
0% by volume is preferred.

The gel electrolyte in the present invention includes a thermoplastic gel composition comprising a polymer such as polyvinylidene fluoride, polyacrylonitrile and polyethylene oxide, a solvent and an electrolyte salt, a polysiloxane having an ethylene oxide chain in a side chain or an ethylene oxide chain. A crosslinked polymer having a polymer in the side chain or main chain, for example, a gel composition composed of a polymer matrix, a solvent and an electrolyte salt formed by crosslinking of urethane, acrylic, epoxy, etc., is particularly effective. is there. The crosslinked polymer matrix will be described in detail. The polymerizable compound used in the present invention contains a hetero atom other than carbon such as an oxygen atom, a nitrogen atom, and a sulfur atom in the molecule. The polymer gel electrolyte is obtained, for example, by dissolving a polymerizable compound containing a hetero atom in a non-aqueous electrolyte and performing a polymerization reaction, and the reaction is preferably performed in an inert gas atmosphere. Further, the type of the polymerizable compound used in the present invention is not particularly limited, and includes those which produce a polymer by causing a polymerization reaction such as thermal polymerization and actinic ray polymerization.

The polymerizable compound used in the present invention includes, for example, monofunctional and polyfunctional (meth) acrylate monomers or prepolymers. In addition, (meth) acrylate in this specification means acrylate or methacrylate. Examples of monofunctional acrylates include alkyl (meth) acrylates [methyl (meth) acrylate, butyl (meth) acrylate, trifluoroethyl (meth) acrylate, etc.], alicyclic (meth) acrylates, etc.], hydroxyalkyl (meth) acrylates [Hydroxyethyl acrylate, hydroxypropyl acrylate, etc.], hydroxypolyoxyalkylene (the oxyalkylene group preferably has 1 carbon atom)
To 4) (meth) acrylates (such as hydroxypolyoxyethylene (meth) acrylate and hydroxypolyoxypropylene (meth) acrylate) and alkoxyalkyl (preferably having 1 to 4 carbon atoms in the alkoxy group) (meth) acrylate [methoxyethyl Acrylate, ethoxyethyl acrylate, phenoxyethyl acrylate, etc.].

Specific examples of other (meth) acrylates include, for example, methylethylene glycol (meth) acrylate, ethylethylene glycol (meth) acrylate, propylethylene glycol (meth) acrylate, phenylethylene glycol (meth) acrylate, methyl Diethylene glycol (meth) acrylate, ethyl diethylene glycol (meth) acrylate, methyl ethoxy diethylene glycol acrylate, methoxy diethylene glycol methacrylate,
Ethylene glycol (meth) acrylate such as methoxytriethylene glycol acrylate, methoxytriethylene glycol methacrylate, and methoxytetraethylene glycol methacrylate; propylene glycol (meth) acrylate such as ethyl propylene glycol acrylate, butyl propylene glycol acrylate, and methoxypropylene glycol acrylate And the like.

The (meth) acrylate may contain a heterocyclic group, which includes oxygen, nitrogen,
It is a heterocyclic residue containing a hetero atom such as sulfur. The type of the heterocyclic group contained in the (meth) acrylate is not particularly limited. For example, a furfuryl group,
Furfuryl (meth) acrylate and tetrahydrofurfuryl (meth) acrylate having a tetrahydrofurfuryl group or the like are preferred. Other (meth) acrylates having a heterocyclic group include furfurylethylene glycol (meth) acrylate, tetrahydrofurfurylethylene glycol (meth) acrylate, furfurylpropylene glycol (meth) acrylate, and tetrahydrofurfurylpropylene glycol (meth) acrylate And alkylene glycol acrylates having a furfuryl group or a tetrahydrofurfuryl group.

The molecular weight of the (meth) acrylate compound and its prepolymer is usually 1,000 or less, preferably 500 or less, more preferably 300 or less. In a polymer gel electrolyte obtained by using a (meth) acrylate monomer having a molecular weight of 1000 or more, a non-aqueous solvent is easily leached. 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 dimethacrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and triethylene glycol di (meth) acrylate.
Acrylate, tripropylene glycol diacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, butanediol (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. No.

In order to form a crosslinked polymer matrix, a combination of a monofunctional monomer and a polyfunctional monomer is particularly preferable. When a polyfunctional monomer is used in combination with a monofunctional monomer, and when the polyfunctional monomer is a polyfunctional (meth) acrylate compound, the amount of the polyfunctional (meth) acrylate compound added to the non-aqueous electrolyte 4% by weight or less,
Preferably it is 0.05 to 2% by weight. Examples of the polymerization initiator for the monomer include carbonyl compounds (benzoin (benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, α-phenylbenzoin, etc.), anthraquinones (anthraquinone, methylanthraquinone, chloranthraquinone). ), Other compounds (benzyldiacetyl, acetophenone, benzophenone, methylbenzoylformate, etc.)], sulfur compounds (diphenylsulfide, dithiocarbamate, etc.), halides of polycondensed ring hydrocarbons (α-chloromethylnaphthalene, etc.) , Pigments (acrylic flavin, fluorescein, etc.), metal salts (iron chloride, silver chloride, etc.), onium salts (P-methoxybenzenediazonium, hexafluoro) Phosphate, diphenyliodonium,
And a photopolymerization initiator such as triphenylsulfonium. These can be used alone or as a mixture of two or more. Preferred photopolymerization initiators are carbonyl compounds, sulfur compounds and onium salts.

Examples of the thermal polymerization initiator include azobisisobutyronitrile, azobisisovaleronitrile, benzoyl peroxide, lauroyl peroxide, ethyl methyl ketone peroxide, bis- (4-t-butylcyclohexyl) peroxydioxy. Examples thereof include carbonate and diisopropyl peroxydicarbonate. Further, a sensitizer and a storage stabilizer can be used together if necessary, and the above-mentioned thermal polymerization initiator, photopolymerization initiator and the like can be used together. As the sensitizer, urea, a nitrile compound (such as N, N-di-p-aminobenzonitrile) and a phosphorus compound (such as tri-n-butylphosphine) are preferable. As the storage stabilizer, a quaternary ammonium chloride is preferable. , Benzothiazole and hydroquinone are preferred. The amount of the polymerization initiator used is usually 0.1
10 to 10% by weight, preferably 0.5 to 7% by weight. The use amount of the sensitizer and the storage stabilizer is usually preferably 0.1 to 5 parts by weight based on 100 parts by weight of the whole polymerizable compound.

The gelation of the electrolyte according to the present invention is carried out by injecting a non-aqueous electrolyte comprising a polymerizable composition containing an acrylate monomer into a sealed container, or coating a support (eg, film, metal, glass) with It is achieved by polymerization with heat or actinic rays. Usually, light, ultraviolet rays, electron beams, X-rays, etc. can be used as the actinic rays. The obtained polymer gel electrolyte is a viscoelastic body by itself, and preferably has an ionic conductivity of 10 when forming a battery.
^-3 S / cm or more and the elastic modulus is 10 ² dyne
/ Cm ² or more. It can also work effectively as a polymer electrolyte layer of a battery. The gelled electrolyte can be made into a product in the form of a film, a sheet, or a composite with a part of the components of the battery in advance.

As the electrolyte salt, as the Lewis acid double salt, for example, LiBF ₄ , LiAsF ₆ , LiPF ₆ , L
iSbF _{6 and the} like, and examples of the sulfonic acid electrolyte salt include LiCF ₃ SO ₃ and LiN (CF ₃ S
O ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiC (CH ₃ ) (C
F ₃ SO ₂ ) ₂ , LiCH (CF ₃ SO ₂ ) ₂ , LiCH
₂ (CF ₃ SO ₂ ), LiC ₂ F ₅ SO ₃ , LiN (C ₂ F ₅ S
O ₂ ) ₂ and LiB (CF ₃ SO ₂ ) ₂ .
It is not limited to this. In addition, LiClO ₄ , L
iCF ₃ CO ₃ , NaClO ₄ , NaBF ₄ , NaSCN,
Examples thereof include KBF ₄ , Mg (ClO ₄ ) ₂ , and Mg (BF ₄ ) ₂ , but are not limited thereto, and are not particularly limited as long as they are used for a normal non-aqueous electrolyte. In addition, these electrolyte salts may be mixed and used. Examples of the non-aqueous electrolyte include those obtained by dissolving an electrolyte salt in the non-aqueous solvent. The concentration of the electrolyte salt in the non-aqueous electrolyte is usually 1.0 to 7.0 mol / l in the non-aqueous solvent. In particular, 1.0 to
5.0 mol / l is preferred. The amount of the nonaqueous electrolyte is preferably 200% by weight or more and 400 to 900% by weight, more preferably 500% by weight, based on the high molecular weight polymer forming the matrix.
~ 800% by weight is preferred. If it is less than 200% by weight, a sufficiently high ionic conductivity cannot be obtained, and if it exceeds 900% by weight, it is difficult to solidify the non-aqueous electrolyte.

The polymer gel electrolyte is used for batteries, capacitors,
It can be used as a polymer gel electrolyte layer in electrochemical elements such as sensors, electrochromic devices, and semiconductor devices. The case where the polymer gel electrolyte of the present invention is used 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 gel electrolyte of the present invention as the electrolyte in this battery, an unprecedented advantageous battery can be obtained. When the gel electrolyte of the present invention is applied to a battery, the gel electrolyte of the present invention itself can also serve as a diaphragm, but the electric field between the electrodes is made uniform, and the strength is improved. In order to improve the reliability, it is preferable to integrate with the diaphragm. In particular, such consideration is necessary for a secondary battery.

The positive electrode active material used in the battery of the present invention is TiS ₂ , MoS ₂ , Co ₂ S ₅ , V ₂ O ₅ , MnO ₂ ,
Examples of transition metal oxides such as CoO ₂ , transition metal chalcogen compounds and composites thereof with Li (Li composite oxide) include LiMnO ₂ , LiMn ₂ O ₄ , LiCoO ₂ , L
iNiO ₂ , LiCo _x Ni _1-x O ₂ (0 <x <1), Li
_{Mn 2-a XaO 4, LiMn} 2-ab X a Y b O 4 (0 <a <
2, 0 <b <2, 0 <a + b <2) and the like. One-dimensional graphite, carbon fluoride, graphite or 10 ⁻² S / c, which is a thermal polymer of an organic substance, is used as the conductive material.
m, a conductive polymer having an electric conductivity of at least m, specifically, polyaniline, polypyrrole, poloazulene, polyphenylene, polyacetylene, polyphthalocyanine, poly-
Examples include polymers such as 3-methylthiophene, polypyridine, and polydiphenylbenzidine, and derivatives thereof.

The negative electrode active material used in the battery of the present invention includes metal negative electrodes such as lithium, lithium aluminum alloy, lithium tin alloy and lithium magnesium alloy, carbon (including graphite and non-graphite), carbon Examples thereof include boron-substituted substances (BC ₂ N) and intercalating substances capable of absorbing lithium ions such as tin oxide. As carbon, graphite, pitch coke, synthetic polymer,
Natural polymer fired bodies can be used. In the present invention,
Insulating or semiconducting carbon, coal, pitch, synthetic polymer or natural polymer obtained by baking a synthetic polymer or natural polymer such as phenol or polyimide in a reducing atmosphere at 400 to 800 ° C. to 800 to 1300.
Conductive carbon bodies, coke, pitch, synthetic polymers, natural polymers obtained by firing in a reducing atmosphere at ℃ C, those obtained by firing in a reducing atmosphere at a temperature of 2000 ° C or higher, natural graphite, etc. Is used.

The positive electrode current collector used in the present invention is, for example, a metal sheet such as stainless steel, gold, platinum, nickel, aluminum, molybdenum or titanium, 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. In particular, it is preferable to use aluminum, stainless steel, or titanium from the viewpoint of electric conductivity, chemical and electrochemical stability, economy, workability, and the like.

The polymer gel electrolyte of the present invention can be used as it is as a battery membrane, but it can also be used by dispersing a filler or compounding it with a porous membrane (separator). Examples of the separator include a nonwoven fabric filter made of glass fiber, a filter, a polymer fiber such as polyester, Teflon, polyflon, polypropylene, and polyethylene, and a nonwoven fabric filter in which glass fiber is mixed with such a polymer fiber. The battery of the present invention comprises a battery element such as an electrode or a diaphragm impregnated with a composition for forming a polymer gel electrolyte, and is converted into a viscoelastic body by polymerization means such as heating or irradiation with actinic rays. Is preferred. The integration of the battery element and the polymer gel electrolyte may be integrated for each battery element.If the battery element and the polymer gel electrolyte are integrated, the positive electrode, the electrode reaction at the negative electrode, and the movement of ions may be performed. It can proceed smoothly and the internal resistance of the battery can be greatly reduced. In particular, when a polymer gel electrolyte containing a halogen-substituted carbonate is used as a battery element, the polymer gel electrolyte has a high modulus of elasticity and a good solvent retention, so that the shape can be thinned, there is no short circuit, and there is no liquid leakage. Thus, a battery having excellent battery characteristics can be obtained.

[0026]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. The non-aqueous solvent and the electrolyte salt are sufficiently purified to a water content of 100
ppm or less, and a battery grade which had been further deoxidized and denitrified, was used, and all operations were performed in an inert gas atmosphere. The ion conductivity was measured at 25 ° C. by using a SUS cylindrical container (inner diameter: 20 mm) whose inner surface except the bottom surface was covered with an insulating tape as a counter electrode. An SUS cylindrical body having a diameter of 18 mm was crimped as a working electrode (cell for measuring ion conductivity). In addition, in the following Examples, a part shows a weight part.

Example 1 Ion conductive polymer solid electrolyte (I) Nonaqueous solvent: propylene carbonate / ethylene carbonate / di (2,2,2-trifluoroethyl) carbonate (4/4/2: volume ratio) 2.0mol / mol
of LiN (CF ₃ SO ₂ ) ₂ solution of 80
After heating to 20 ° C and adding 20 parts of polyacrylonitrile, the mixture was cooled to 10 ° C and solidified. The ionic conductivity was measured to be 2.7 × 10 ⁻³ S / cm, and the elastic modulus was 3.
It was 0 × 10 ³ dyne / cm ² .

Comparative Example 1 An electrolyte was solidified in the same manner as in Example 1 except that di (2,2,2-trifluoroethyl) carbonate as a non-aqueous solvent was changed to dipropyl carbonate. The ionic conductivity is 2.3 × 10 ⁻³ S / cm, and the elastic modulus is 8.0 × 10 ² dy.
ne / cm ² .

Example 2 Ion-conductive polymer solid electrolyte (II) Non-aqueous solvent: propylene carbonate / ethylene carbonate / methyl-2,2,2-trichloroethyl carbonate (relative permittivity: 4.9) (3/3) (85%) of a 1.8 mol / l solution of LiC (CF ₃ SO ₂ ) ₃ dissolved in E.C./4 (volume ratio) was heated to 60 ° C., 15 parts of polyvinylidene fluoride was added, and then cooled to 10 ° C. And solidified.
The ionic conductivity was 2.4 × 10 ⁻³ S / cm, and the elastic modulus was 3.5 × 10 ³ dyne / cm ² .

Comparative Example 2 Non-aqueous solvent methyl-2,2,2-trichloroethyl carbonate was replaced with diisopropyl carbonate (dielectric constant;
The electrolyte was solidified in the same manner as in Example 2 except that 2.5) was used. The ionic conductivity was 1.9 × 10 ⁻³ S / cm, and the elastic modulus was 1.0 × 10 ³ dyne / cm ² .

Example 3 Ion-conductive polymer solid electrolyte (III) Non-aqueous solvent: ethylene carbonate / methyl-2,2,2
-Trifluoroethyl carbonate (1/1: volume ratio)
20 parts of methyldiethylene glycol methacrylate as a monofunctional monomer and 0.06 parts of benzoin isobutyl ether as a photoinitiator were mixed and dissolved in 80 parts of a 2.0 mol / l LiPF ₆ electrolytic solution dissolved in water to prepare a photopolymerizable solution. did. This solution was placed in a cell for measuring ion conductivity, and irradiated with ultraviolet light from a high-pressure mercury lamp to solidify the electrolytic solution. The ionic conductivity was 3.0 × 10 ⁻³ S / cm, and the elastic modulus was 4.1 × 10 ³ dyne / cm ² .

Comparative Example 3 An electrolytic solution was solidified in the same manner as in Example 3, except that methyl-2,2,2-trifluoroethyl carbonate as a non-aqueous solvent was changed to dimethoxyethane. This ionic conductivity is 9.7.
× 10 ^-4 S / cm, elastic modulus 6.0 × 10 ² dyne /
cm ² .

Example 4 Ion conductive polymer solid electrolyte (IV) Non-aqueous solvent: propylene carbonate / ethylene carbonate / methyl-2-chloroethyl carbonate (2/3
/1.5:volume ratio) dissolved in 1.6 mol / l LiCF
15 parts of diethylene glycol dimethacrylate and 0.05 part of benzoin isopropyl ether as a photoinitiator were mixed and dissolved in 75 parts of ₃ SO ₃ electrolyte to prepare a photopolymerizable solution. Thereafter, the electrolyte was solidified in the same manner as in Example 3. The ionic conductivity was 2.4 × 10 ⁻³ S / cm, and the elastic modulus was 3.8 × 10 ³ dyne / cm ² .

Comparative Example 4 An electrolytic solution was solidified in the same manner as in Example 4 except that dimethoxyethane was used instead of methyl-2-chloroethyl carbonate. The ionic conductivity is 2.2 × 10 ⁻³ S /
cm, and the elastic modulus was 7.0 × 10 ² dyne / cm ² .

Example 5 Ion conductive polymer solid electrolyte (V) Nonaqueous solvent: propylene carbonate / ethylene carbonate / methyl-2,2,3,3,3-pentafluoropropyl carbonate (2/5/3: volume 86 parts of a 2.0 mol / l LiN (CF ₃ SO ₂ ) ₂ solution dissolved in 1 mol / l of ethyl diethylene glycol methacrylate as a monofunctional monomer, and PO-modified trimethylolpropane as a polyfunctional monomer. 0.2 parts of triacrylate and 0.05 parts of methylbenzoylformate as a photoinitiator were added, mixed and dissolved to prepare a photopolymerizable solution. The electrolyte was solidified in the same manner as in Example 3. When this ionic conductivity was measured, it was 2.7 × 10 ⁻³ S / cm,
The elastic modulus was 3.8 × 10 ³ dyne / cm ² .

Comparative Example 5 An electrolytic solution was solidified in the same manner as in Example 5 except that methyl-2,2,3,3,3-pentafluoropropyl carbonate as a non-aqueous solvent was changed to di-n-propylene carbonate. The ionic conductivity was 1.7 × 10 ⁻³ S / cm, and the elastic modulus was 5.6 × 10 ² dyne / cm ² .

Example 6 Ion conductive polymer solid electrolyte (VI) Non-aqueous solvent: dissolved in propylene carbonate / ethylene carbonate / methyl-2,2,2-trifluoroethyl carbonate (3/3/4: volume ratio) 1.8 mol
Per liter of a LiBF ₄ solution in 85 parts of an electrolytic solution, 14.9 parts of methoxytriethylene glycol acrylate as a monofunctional monomer, 0.1 part of dipentaerythritol hexamethacrylate as a polyfunctional monomer, and methylbenzoyl phosphate as a photoinitiator. 0.05 part of the mate was added, mixed and dissolved to prepare a photopolymerizable solution. The electrolyte was solidified in the same manner as in Example 3. This ionic conductivity is 2.6 × 10 ^−3.
The S / cm and the elastic modulus were 3.5 × 10 ³ dyne / cm ² .

Comparative Example 6 An electrolyte was solidified in the same manner as in Example 6, except that dimethoxyethane was used as the non-aqueous solvent methyl-2,2,2-trifluoroethyl carbonate. The ionic conductivity is 2.3 × 1
0 ^-3 S / cm, elastic modulus is 8.4 × 10 ² dyne / cm ²
Met.

Example 7 Ion-conductive polymer solid electrolyte (VII) Non-aqueous solvent: propylene carbonate / ethylene carbonate / methyl-2-chloroethyl carbonate (2/5
/ 3: volume ratio) and 2.0 mol / l LiAs dissolved in
To 80 parts of the electrolyte solution of the F ₆ solution, 14.7 parts of methoxydiethylene glycol acrylate as a monofunctional monomer, 0.3 parts of diethylene glycol diacrylate as a polyfunctional monomer, and 0.05 parts of methylbenzoyl formate as a photoinitiator were added and mixed. After dissolution, a photopolymerizable solution was prepared. The electrolyte was solidified in the same manner as in Example 3. The ionic conductivity is 3.2 × 10 ⁻³ S / cm, and the elastic modulus is 3.1.
× 10 ³ dyne / cm ² .

Example 8 Ion conductive polymer solid electrolyte (VIII) Non-aqueous solvent: propylene carbonate / ethylene carbonate / di (2,2,2-trifluoroethyl) carbonate (2/3/5: volume ratio) 1.8 mol / mol
1 of LiN (CF ₃ SO ₂ ) ₂ solution and 0.2 mol / l of LiPF ₆ solution.
4.0 parts, 1.0 part of trimethylolpropane triacrylate as a polyfunctional monomer, and 0.05 parts of bis (4-t-butylcyclohexyl) peroxydicarbonate as a thermal polymerization initiator were mixed and dissolved. A polymerization reaction was performed to solidify the electrolyte. This ionic conductivity is 3.4
× 10 ⁻³ S / cm, elastic modulus is 3.2 × 10 ³ dyne /
cm ² .

Comparative Example 7 An electrolytic solution was solidified in the same manner as in Example 7, except that di (2,2,2-trifluoroethyl) carbonate, a non-aqueous solvent, was changed to diisopropyl carbonate. The ionic conductivity is 2.0 × 10 ⁻³ S / cm, and the elastic modulus is 7.3 × 10 ² dy.
ne / cm ² .

Example 9 Ion conductive polymer solid electrolyte (IX) Non-aqueous solvent: propylene carbonate / ethylene carbonate / methyl-2-chloroethyl carbonate (3/3
1.6 mol / l LiCF ₃ dissolved in (/ 4: volume ratio)
Equivalent mixed solution of SO ₃ solution and 0.2 mol / l LiBF ₄ solution 75 parts of ethoxydiethylene glycol methacrylate as monofunctional monomer, 5 parts of diethylene glycol dimethacrylate as polyfunctional monomer, 5 parts as photoinitiator 0.05 parts of benzoin isopropyl ether was mixed and dissolved to prepare a photopolymerizable solution.
Thereafter, the electrolyte was solidified in the same manner as in Example 3. The ionic conductivity is 2.4 × 10 ⁻³ S / cm, and the elastic modulus is 2.9 ×
It was 10 ³ dyne / cm ² .

Example 10 Ion-conductive polymer solid electrolyte (X) Non-aqueous solvent: propylene carbonate / di (2,2,2-
(Trifluoroethyl) carbonate (6/4: volume ratio)
1.5 mol / l LiN (CF ₃ SO ₂ ) ₂ dissolved in
Equivalent mixture of a solution and a 0.5 mol / l LiAsF ₆ solution 85 parts of a mixed electrolyte, 14.0 parts of methyldiethylene glycol acrylate as a monofunctional monomer and 1.0 part of trimethylolpropane triacrylate as a polyfunctional monomer are mixed and dissolved. Then, a polymerizable solution was prepared. The solution was irradiated with an electron beam to solidify the electrolyte. The ionic conductivity is 3.8 × 10 ⁻³ S / cm, and the elastic modulus is 3.6 ×
It was 10 ³ dyne / cm ² .

Example 11 Ion conductive polymer solid electrolyte (XI) Non-aqueous solvent: trifluoromethyl ethylene carbonate /
Ethyl diethylene glycol acrylate 13.8 parts as a monofunctional monomer and trimethylolpropane triacrylate 0 as a polyfunctional monomer were added to 86 parts of an electrolyte solution of a 1.8 mol / l LiPF ₆ solution dissolved in ethylene carbonate (7/3: volume ratio). .2 parts and 0.06 parts of benzoin isopropyl ether as a photoinitiator were added, mixed and dissolved to prepare a photopolymerizable solution. The electrolyte was solidified in the same manner as in Example 3. The ionic conductivity is 1.8 × 10 ^-3
The S / cm and the elastic modulus were 1.4 × 10 ⁴ dyne / cm ² .

Example 12 Ion conductive polymer solid electrolyte (XII) Non-aqueous solvent: 1. Dissolved in difluoromethylethylene carbonate / methyl-2,2,2-trifluoroethyl carbonate (5/5: volume ratio) 5mol / l Li
Ethyl glycol acrylate 13.8 parts Monofunctional monomers in the electrolytic solution 86 parts of PF ₆ solution, 0.2 parts of trimethylolpropane triacrylate as a polyfunctional monomer, admixed dissolved 0.06 parts of benzoin isopropyl ether as a photoinitiator Then, a photopolymerizable solution was prepared. The electrolyte was solidified in the same manner as in Example 3. The ionic conductivity is 2.8 × 10 ⁻³ S / cm, and the elastic modulus is 4.
It was 0 × 10 ³ dyne / cm ² .

Example 13 The gel electrolytes obtained in Examples 1 to 12 and Comparative Examples 1 to 7 were left in an inert gas atmosphere, and the retention of the solvent in the gel electrolyte was evaluated (Tables 1 and 2). 3).

Example 14 (Evaluation of Characteristics of Negative Electrode Battery) 2 parts by weight of polyvinylidene fluoride was dissolved in 58 parts by weight of N-methylpyrrolidone, and 40 parts by weight of a coke calcined at 2500 ° C. were added. The mixture was mixed and dispersed under an active atmosphere to prepare a negative electrode paint. This was applied on a 20 μm copper foil using a wire bar in the air, dried at 100 ° C. for 15 minutes, and the film thickness was 60 μm
Was prepared. This was used as a negative electrode, the counter electrode was a Li plate, and charge and discharge tests were performed using the gel electrolytes prepared in Examples 1 to 10 and Comparative Examples 1 to 7. The charge / discharge test was performed using a Hokuto Denko HJ-201B charge / discharge measurement device, and the charge / discharge test was performed for 1.5 hours.
The battery was charged at a constant current until the current reached 0 V at a constant current of 3 mA for 3 hours. After a pause of 1 hour, the battery was discharged at a current of 1.5 mA to a voltage of 0.8 V. Thereafter, the charging and discharging were repeated.
Tables 1, 2, and 3 show the cycle characteristics of the negative electrode battery at this time. The evaluation of the solvent retention in the table and the evaluation of the battery characteristics after 300 cycles were evaluated in four stages from excellent to inferior.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

【The invention's effect】

1. Claims 1 to 9 An ion-conductive polymer gel electrolyte having an improved elastic modulus and an improved solvent-holding power without a decrease in ionic conductivity was obtained. By using a crosslinked polymer matrix as the polymer matrix, a gel-like solid electrolyte having particularly sufficient solid strength and high solvent holding power can be prepared. 2. [Claim 10] A solid battery having sufficient solid strength without liquid leakage, thin, and short-circuit can be manufactured.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C08L 101/00 C08L 101/00 (72) Inventor Toshiyuki Osawa 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Company, Ltd. (72) Inventor Keiichi Yokoyama 580-32, Takuji Nagaura, Sodegaura-shi, Chiba Mitsui Petrochemical Industry Co., Ltd. (72) Akio Hinohara 580-32, Takuji Nagaura, Sodegaura-shi, Chiba Mitsui Oil Inside Chemical Industry Co., Ltd. (72) Inventor Masahiro Torida 580-32 No. Takuji Nagaura, Sodegaura City, Chiba Prefecture Inside Mitsui Petrochemical Industry Co., Ltd.

Claims (10)

[Claims] 1. A polymer gel electrolyte containing at least a polymer matrix, a non-aqueous electrolyte and an electrolyte salt, wherein the non-aqueous electrolyte contains at least one halogen-substituted carbonate as a solvent. Ion conductive polymer gel electrolyte. 2. The ion-conductive polymer gel electrolyte according to claim 1, wherein the halogen-substituted carbonate is a halogen-substituted acyclic carbonate. 3. The ion-conductive polymer gel electrolyte according to claim 1, wherein the solvent of the non-aqueous electrolyte contains a halogen-substituted carbonate and a cyclic carbonate. 4. The ion-conductive polymer gel electrolyte according to claim 1, wherein the relative dielectric constant of the halogen-substituted carbonate ester is 4.0 or more. 5. The halogen-substituted carbonate according to claim 1, wherein the halogen-substituted carbonate is a halogen-substituted acyclic carbonate represented by the general formula [I] and / or a halogen-substituted cyclic carbonate represented by the general formula [II]. 5. The ion-conductive polymer gel electrolyte according to item 4. Embedded image Embedded image (In the above formula, R ¹ and R ² represent a halogen-substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, hydrogen, or halogen.
At least one of R ¹ and R ² always has at least one halogen. R ³ and R ⁴ represent a halogen-substituted or unsubstituted alkyl group having 1 to 2 carbon atoms, hydrogen, or halogen. However, at least one of R ³ and R ⁴ always has at least one halogen. ) 6. The ion-conductive polymer gel electrolyte according to claim 5, wherein the halogen-substituted carbonate of the general formula [I] or [II] is a fluorine-substituted carbonate. 7. The ion-conductive polymer gel electrolyte according to claim 1, wherein the polymer matrix is a crosslinked polymer matrix. 8. The ion-conductive polymer gel according to claim 1, wherein the content of the non-aqueous electrolyte is at least 200% by weight or more based on the polymer matrix. Electrolytes. 9. The method according to claim 1, wherein the acrylate monomer constituting the polymer matrix is modified with at least one alkylene oxide.
9. The ion-conductive polymer gel electrolyte according to 7 or 8. 10. The method of claim 1, 2, 3, 4, 5, 6, 7,
10. A solid battery comprising the ion-conductive polymer gel electrolyte according to 8 or 9 as a constituent element.