JP2002208437A - Polymer solid electrolyte, and secondary cell using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer solid electrolyte with high ion conductivity and electrochemical stability, and to provide a secondary cell using this polymer solid electrolyte with excellent load property and cycle property. SOLUTION: The polymer solid electrolyte, used by the secondary cell, contains a polymer, a compound expressed by the formula (1) or (2), and a salt of the metal belonging to I or a II a group of the periodic table.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a solid polymer electrolyte used for a primary battery, a secondary battery, a capacitor, and the like, and a secondary battery using the same. More specifically, the present invention relates to an acrylate or methacrylate-based polymer solid electrolyte having excellent load characteristics and cycle characteristics, and a secondary battery using the same.

[0002]

2. Description of the Related Art Conventionally, liquid electrolytes have been used for electrochemical devices such as primary batteries, secondary batteries, and capacitors. However, when a liquid electrolyte is used, there is a concern about leakage from a product container, and therefore, there has been a demand for an improvement for improving long-term reliability in using an electrochemical element.

As one improvement method, a method using a solid electrolyte instead of a liquid electrolyte has been studied.
If a solid electrolyte is used, there is no fear of liquid leakage, so that a highly reliable element can be provided, and there is an advantage that the element itself can be reduced in size and weight at the same time.

In recent years, among solid electrolytes, polymer solid electrolytes have attracted attention and have been studied. The polymer solid electrolyte is
Because of its flexibility, it is estimated that it is possible to flexibly cope with a volume change occurring in the ion-electron exchange reaction process between the electrode and the electrolyte. Therefore, expectations for practical use are increasing.

As an example of such a solid polymer electrolyte, a composite of polyethylene oxide having a polyether structure and an alkali metal salt such as a lithium salt is known. JP-A-5-25353 mainly discloses a crosslinked resin and a salt of a polyoxyalkylene diester compound, a polymethoxyoxyalkylene ester compound, and a copolymer of an oxy compound having a double bond. A polymer solid electrolyte as a constituent component is described. Further, JP-A-6-223842 describes a polymer solid electrolyte comprising an organic polymer substance having a carbonate group as a functional group and a metal salt.

On the other hand, Japanese Patent Application Laid-Open No. 1-241764 describes that a polycarbonate methacrylate resin obtained by polymerizing a methacrylic acid ester of a polycarbonate polyol has excellent properties as a polymer electrolyte material.

In general, since a solid electrolyte has a lower ionic conductivity than a liquid electrolyte, it is difficult to manufacture a battery having excellent charge / discharge characteristics. Therefore, it is necessary to coexist a carbonate compound or the like as a plasticizer in the solid electrolyte. Proposed.

In order to realize a primary battery and a secondary battery which are excellent in charge / discharge characteristics and operate stably in a high temperature environment using a solid electrolyte, they have high ionic conductivity and excellent electrochemical stability. The appearance of a low-cost and solid polymer electrolyte is desired.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid polymer electrolyte having high ionic conductivity and excellent electrochemical stability. Another object of the present invention is to provide a secondary battery using such a solid polymer electrolyte and having excellent load characteristics and cycle characteristics.

[0010]

According to the present invention, there is provided a polymer solid comprising a compound represented by the formula (1) or (2) and a metal salt of Group 1a or 2a of the periodic table. Provide electrolyte.

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The above-mentioned high molecular compound is characterized in that a part or all of the hydroxyl groups of at least one kind of polyol compound selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols and polyester carbonate polyols is formed of acrylic acid or methacrylic acid. Is a preferred embodiment of the present invention.

The metal salt of Group 1a or 2a of the periodic table is a lithium salt or a magnesium salt,
A solid polymer electrolyte that is iPF ₆ or LiBF ₄ is a preferred embodiment of the present invention.

Further, the present invention provides a secondary battery containing the above-mentioned solid polymer electrolyte.

Further, the present invention provides a polymer solid electrolyte as described above, as a negative electrode active material, metallic lithium, a lithium-containing alloy, a carbon material capable of doping and undoping lithium ions, and capable of doping and undoping lithium ions. A negative electrode containing at least one selected from the group consisting of tin oxide, silicon capable of doping and undoping lithium ions, and titanium oxide capable of doping and undoping lithium ions; lithium and a transition metal as positive electrode active materials; And a positive electrode containing the composite oxide of the above.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The solid polymer electrolyte according to the present invention and each structure of a secondary battery using the same will be described below. In the present invention, acrylate and methacrylate are collectively referred to as (meth) acrylate.

The solid polymer electrolyte according to the present invention comprises a polymer compound, a compound represented by the following formula (1) or (2), and a metal salt of Group 1a or 2a of the periodic table. Is a solid polymer electrolyte.

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The secondary battery of the present invention is a secondary battery containing the solid polymer electrolyte of the present invention.

Polymer Compounds The polymer compounds that can be used in the present invention include:
Examples thereof include polymers of ester compounds in which some or all of the hydroxyl groups of polyether polyol, polycarbonate polyol, polyester polyol, or polyester carbonate polyol have been converted to (meth) acrylic esters.

[0019] As a method of obtaining an ester compound such ester compounds, polyether polyols, polyester polyols, some or all of the hydroxyl groups possessed by the at least one polyol compound selected from the group consisting of polycarbonate polyols and polyester carbonate polyols, Is reacted with acrylic acid or methacrylic acid.

Examples of the above ester compounds include polyether (meth) acrylate, polycarbonate (meth)
Examples include acrylate, polyester (meth) acrylate, and polyester carbonate (meth) acrylate. Here, the polyol means an alcohol having 2 or more hydroxyl groups.

The polyether polyol, polycarbonate polyol or polyester polyol used for producing the ester compound has a weight average molecular weight of 200 to 100,000, preferably 250 to 100,000.
20,000, more preferably 300 to 10,000 is desirable.

Examples of the method for obtaining the above-mentioned polyether polyol include a method of polymerizing an alkylene oxide and a method of adding an alkylene oxide to a polyhydric alcohol.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, oxetane, and tetrahydrofuran. These may be used alone or in combination of two or more.

As the polyhydric alcohol, the same glycols and polyols as described above can be used.

As a specific example of the polyether polyol,
Polyethylene glycol, polypropylene glycol,
Polybutylene glycol can be mentioned.

The above-mentioned polycarbonate polyol compound can be synthesized by polycondensation with a dihydric or higher polyhydric alcohol and a carbonic acid diester or phosgene.

Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl- 1,5-pentanediol, 1,6
-Hexanediol, 1,8-octanediol, 1,
3-bis (2-hydroxyethoxy) benzene, 1,4
Diols such as -bis (2-hydroxyethoxy) benzene, neopentyl glycol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol Also, trimethylolpropane, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, glycerin, polyols such as sorbitol, and 1 to 5 equivalents of ethylene oxide based on the hydroxyl groups of these polyols,
Examples thereof include propylene oxide and other alcohols having a hydroxyl group to which an alkylene oxide has been added. These polyhydric alcohols may be used alone or in combination of two or more.

As the carbonic acid diester, dimethyl carbonate,
Examples thereof include diethyl carbonate, diisopropyl carbonate, ethylene carbonate, and propylene carbonate. These may be used alone or in combination of two or more.

The polyester polyol can be synthesized by a method of polycondensing hydroxycarboxylic acid or lactone, or a method of polycondensing polyhydric alcohol and polycarboxylic acid.

Here, the hydroxycarboxylic acid or lactone includes hydroxyacetic acid, lactic acid, β-propiolactone, β-butyrolactone, γ-butyrolactone, γ
Valerolactone, γ-caprolactone, γ-heptalactone, γ-octalactone, γ-nonalactone, γ-
Decanolactone, δ-valerolactone, β-methyl-δ
Valerolactone, δ-hexalactone, δ-octalactone, δ-decanolactone, δ-nonalactone, ε-
And caprolactone. In addition, in order to make a terminal functional group into a hydroxyl group, a polyhydroxy compound having 2 to 6 valences is usually added as a polymerization initiator, and polycondensation is performed.

When a polyester polyol is synthesized by polycondensation of a polyhydric alcohol and a polycarboxylic acid, the polyhydric alcohol may be ethylene glycol, 1,2-
Propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8
-Octanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,3-bis (2-hydroxyethoxy) benzene, 1,4-bis (2- Hydroxyethoxy) benzene, 1,4-cyclohexanediol, 1,
Glycols such as 4-cyclohexanedimethanol,
Alternatively, polyols such as trimethylolpropane, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, glycerin, sorbitol and the like can be mentioned.

Examples of polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, cyclohexane-1,2-dicarboxylic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,
Examples thereof include 4-dicarboxylic acid, cis-tetrahydrophthalic acid, phthalic acid, isophthalic acid, and terephthalic acid. Further, a corresponding acid anhydride or dialkyl dicarboxylate may be used in place of the dicarboxylic acid.

The above-mentioned polyester carbonate polyol can be synthesized from the above-mentioned polyester polyol and diester carbonate or phosgene. When using a carbonic acid diester, dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate and the like can be exemplified, and these can be used alone or in combination of two or more. Is also good.

Production of Polymer Compound The polymer compound of the present invention is preferably a polymer obtained by polymerizing the ester compound. When a polymer is produced from one or more ester compounds containing a (meth) acrylate group, the weight average molecular weight of the polymer is preferably 10,000 or more. When a gel electrolyte is used, a high molecular weight crosslinked polymer having low solubility in a solvent in the electrolytic solution is preferably used. For the production of the high molecular weight crosslinked polymer, the same method and conditions as those of a conventionally known method usually used for crosslinking of poly (meth) acrylate can be adopted.

As a method for polymerizing one or more of the ester compound monomers containing a (meth) acrylate group, irradiation with ultraviolet rays or radiation or heating is carried out in the presence of the ester compound. it can. At that time, if necessary, another copolymerizable monomer may be allowed to coexist. In the polymerization, a solvent may be used.

Examples of other copolymerizable monomers include vinyl monomers and vinylidene monomers, and more specifically, vinyl esters, vinyl ethers, (meth) acrylates, allyl ethers, and allyl esters are preferred. Specific examples include ethyl (meth) acrylate,
Ethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, 2- (dimethylamino) ethyl (meth) acrylate, 2- (diethylamino) ethyl (meth) acrylate, 2- (di-n-propylamino) ethyl (Meth) acrylate, 2- (dii-propylamino) ethyl (meth) acrylate, 3- (dimethylamino) propyl (meth) acrylate, 1-piperidineethyl (meth) acrylate, 2-N-morpholinoethyl (meth) ) Acrylate, 2- (dimethylamino) ethoxyethyl (meth) acrylate, 2,2,
6,6-tetramethylpiperidin-4-yl (meth) acrylate, 1-methyl-2,2,6,6-tetramethylpiperidin-4-yl (meth) acrylate N, N-
Dimethylaminoethyl (meth) acrylate, N-methyl-2,2,6,6-tetramethyl-polyethylene glycol (meth) acrylate, allyl alcohol, vinyl acetate, styrene, α-methylstyrene, vinyl chloride, vinylidene chloride, fluoride Examples include vinyl, vinylidene fluoride, acrylonitrile, vinyl cyanoacetate, allylamine, isopropylacrylamide vinylene carbonate, and maleic anhydride.

In the case of polymerization by an ultraviolet irradiation method, a photosensitizer can be used, and examples of such a photosensitizer include benzophenone, acetophenone, 2,2-dimethoxy-2-phenylacetophenone and the like. .

When the polymerization is carried out by a heating method, a thermal polymerization initiator can be used. Depending on the polymerization mode, peroxides such as benzoyl peroxide and peroxydicarbonate, and 2,2'-azobisisopropane can be used. An azo compound such as butyronitrile, a nucleophile such as an alkali metal, or an electrophile such as a Lewis acid can be used alone or in combination.

When a solvent is used, the use of a non-aqueous solvent is preferred. Examples of such solvents include methanol, ethanol, propanol, butanol, alcohols such as ethylene glycol, dichloromethane, chloroform, halogenated hydrocarbons such as dichloroethane, benzene, toluene, aromatic hydrocarbons such as xylene, and hexane. , Heptane, decane, saturated hydrocarbons such as cyclohexane, ethers such as diethyl ether and tetrahydrofuran (THF), ethylene carbonate,
Propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, carbonates such as dipropyl carbonate, ethyl acetate,
Propyl acetate, butyl acetate, γ-butyrolactone, δ-
Esters such as valerolactone and ε-caprolactone can be mentioned. At this time, the ratio of the polymer compound to the non-aqueous solvent (polymer compound) / (non-aqueous solvent) is desirably 0.02 to 10, preferably 0.04 to 1 by weight.

After polymerization, the resulting polymer is obtained in the form of powder, film, gel, etc., and can be used as a solid electrolyte. When the reaction proceeds in the presence of a solvent, a gel is usually formed, but the gel can be used as it is as a material for the polymer electrolyte,
Further, if necessary, it can be used as a polymer in the form of a film or powder from which the solvent has been removed by drying.

Polymer Solid Electrolyte The polymer solid electrolyte according to the present invention comprises the above-mentioned polymer compound, a compound represented by the following formula (1) or (2) and a metal salt of Group 1a or 2a of the periodic table. Is a solid polymer electrolyte.

In a preferred embodiment of the polymer solid electrolyte, one or more ester compounds containing a (meth) acrylate group are irradiated with ultraviolet light or radiation in the presence or absence of another copolymerizable monomer. A polymer solid electrolyte comprising a polymer produced by irradiation or heating and containing a compound represented by the above formula (1) or (2) and a metal salt of Group 1a or 2a of the periodic table. is there.

[0043]

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As the metal salt of Group 1a of the periodic table, compounds such as lithium, sodium and potassium are preferable.

The concentration of the metal salt in the solid polymer electrolyte in the present invention is preferably 0.1 to 10 mol / l, more preferably 0.5 to 2 mol / l.

As a specific example of the metal salt, LiPF₆, Li
BF₄, LiClO₄, LiAsF₆, LI₂SiF₆, L
i [(CF₃)₃PF₃], Li [(C₂F₅)₃PF
₃] And other lithium salts. Also, the general formula Li
OSO₂R¹², LiN (SO ₂R¹³) (SO
₂R¹⁴), LiC (SO₂R^Fifteen) (SO₂R¹⁶) (SO
₂R¹⁷), LiN (SO₂OR¹⁸) (SO₂OR¹⁹)
(Where R¹²~ R¹⁹Are identical but different
May be a perfluoroalkyl having 1 to 8 carbon atoms
Use a lithium salt such as
Can be.

These lithium salts may be used alone or in combination of two or more.

The metal salt of Group 2a of the periodic table is a compound of magnesium, and specific examples thereof include Mg (C
lO ₄ ) ₂ , Mg (BF ₄ ) ₂ , Mg (PF ₆ ) ₂ , M
and magnesium salts such as g (SO ₃ CF ₃ ) ₂ .

Of these, in particular, LiPF₆, LiBF_Four,
Li [(CF₃)₃PF₃], Li [(C₂F₅)₃P
F₃], LiOSO₂R³, LiN (SO₂R¹³) (SO
₂R ¹⁴), LiC (SO₂R^Fifteen) (SO₂R¹⁶) (SO
₂R¹⁷), LiN (SO₂OR ¹⁸) (SO₂OR¹⁹)
(Where R¹²~ R¹⁹Are identical but different
May be a perfluoroalkyl having 1 to 8 carbon atoms
And more preferably LiPF₆You
And LiBF₄It is.

In the production of the solid polymer electrolyte of the present invention, a polymer produced from one or more ester compounds containing a (meth) acrylate group is represented by the formula (1) or (2). A method of mixing the compound and a metal salt of Group 1a or 2a of the Periodic Table, or a compound represented by the formula (1) or (2) and a Group 1a or Group 1 of the Periodic Table during polymerization of the ester compound. The polymerization can be carried out by a method in which polymerization is carried out in the presence of a metal salt of Group 2a.

Particularly, the latter method is preferable because a solid electrolyte in which a metal salt is uniformly dispersed in a polymer can be easily obtained. At this time, the above equation (1) or (2)
The amount of the compound represented by is preferably 0.1 to 200 parts by weight, more preferably 1 to 100 parts by weight, based on 100 parts by weight of the polymer compound.

For example, one or more ester compounds containing a (meth) acrylate group in advance, a compound represented by the above formula (1) or (2),
A metal salt of group a or group 2a, and if necessary, a solvent are added, and a uniform mixture thereof is coated on a flat substrate, and then polymerized and gelled by light irradiation, radiation irradiation, or heating. You can proceed. Thus, a polymer solid electrolyte thin film having a thickness of 0.1 to 1000 μm can be obtained. In addition, when heating, it is desirable to perform in the temperature range which does not decompose | dissolve an electrolyte salt, for example, 0-100 degreeC, Preferably it is 20-90 degreeC.

In the solid polymer electrolyte according to the present invention, the compound represented by the formula (1) or (2), the polymer compound and the metal salt of Group 1a or 2a of the Periodic Table are included. May further contain a non-aqueous solvent such as a carbonate ester. At this time, the ratio of the polymer compound to the non-aqueous solvent (polymer compound) / (non-aqueous solvent) was 0.02 to 1 in weight ratio.
0 is preferable, and 0.04 to 1 is more preferable.
In order to include a non-aqueous solvent in the polymer compound, polymerization may be performed in the presence of a non-aqueous solvent when producing a polymer solid electrolyte, or a method of impregnating the non-aqueous solvent after polymerization. And so on.

As the non-aqueous solvent, carbonate esters or lactones can be suitably used. Examples of carbonates include ethylene carbonate, propylene carbonate,
Linear or cyclic carbonates such as dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate and dipropyl carbonate, and examples of lactones include γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

The solid polymer electrolyte according to the present invention has excellent liquid retention properties in a state containing a nonaqueous solvent, high ionic conductivity, and excellent storage stability in a charged state. Such a polymer solid electrolyte can be used for, for example, primary batteries, secondary batteries, capacitors, electrochemical devices such as electrochromic display devices, and medical actuators. In particular, this polymer solid electrolyte is suitable for use as a substitute for an organic electrolytic solution of a lithium ion secondary battery. Further, it can be used as a binder used for dispersing and fixing the powdery electrode material on the current collector.

Secondary Battery A secondary battery according to the present invention comprises: a negative electrode containing a negative electrode active material;
It is composed of a positive electrode containing a positive electrode active material and the above-mentioned solid polymer electrolyte disposed therebetween.

As the negative electrode active material, metallic lithium, a lithium-containing alloy, a material capable of doping and undoping lithium ions, or the like can be used. Materials capable of doping and undoping such lithium ions include carbon materials, tin oxide, silicon,
It can be appropriately selected from titanium oxide, transition metal nitride, and the like. Among these, a carbon material capable of doping and undoping lithium ions is preferable, and it may be graphite or amorphous carbon. Specific examples include activated carbon, carbon fiber, carbon black, mesocarbon microbeads, and natural graphite.

As the positive electrode active material, MoS ₂ , Ti
Transition metal oxides or sulfides such as S ₂ , MnO ₂ , V ₂ O ₅ , LiCoO ₂ , LiMnO ₂ , LiM
_{n 2 O 4, LiNiO 2,} LiNi x Co (1-x) O 2
And conductive polymer compounds such as polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, and dimercaptothiadiazole / polyaniline composite, and disulfide compounds. Among these, a composite oxide composed of lithium and a transition metal is particularly preferable.

When such a polymer solid electrolyte is used in a secondary battery, a battery can be manufactured by forming the polymer solid electrolyte into a film in advance and sandwiching it between a positive electrode and a negative electrode. Instead of a film, a polymer solid electrolyte formed in a gel in advance can be arranged.

Further, in the battery manufacturing process including the step of forming a three-layer structure of a positive electrode, a separator and a negative electrode and then impregnating the same with an electrolytic solution, the above formula (1) or (2) is used instead of the electrolytic solution. It is also possible to adopt a method of adding and impregnating a solution comprising a compound represented by the formula (1), a polymer compound, a metal salt of Group Ia or Group 2a of the Periodic Table, and a non-aqueous solvent, followed by gelation.

In any case, by using the above-mentioned solid polymer electrolyte according to the present invention, it is possible to manufacture a secondary battery while minimizing the modification of the conventional battery manufacturing process. The shape of the battery may be any shape such as a film type, a coin type, a cylindrical type, or a square type.

[0062]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Synthesis Example 1) Adipic acid 29 was placed in a glass reaction vessel equipped with a stirrer, thermometer and Liebig condenser.
2 g (2.0 mol), 318 g of diethylene glycol
(3.0 mol), and titanium tetrabutoxide 12 m
g, and gradually heated from 160 ° C. to 230 ° C.
The reaction was continued for 24 hours while removing generated water out of the reaction system. As a result, the desired polyester diol was obtained as a colorless oil in a yield of 538 g.

(Synthesis Example 2) The polyester diol obtained in Synthesis Example 1 (OH value: 208 mg KOH / OH) was placed in a glass reaction vessel equipped with a stirrer, a thermometer and a Dean Stark.
g) 53.8 g, acrylic acid 14.4 g, p-toluenesulfonic acid monohydrate 1.08 g, 4-methoxyphenol 0.11 g and toluene 100 ml were charged. 6
The resulting water was removed from the reaction system while heating and refluxing for an hour. After lowering the temperature to 50 ° C., 4.08 g of acetic anhydride was used.
Was further added and stirring was continued at this temperature for 2 hours. Then, at 50 ° C, K, a solid base product of Kyowa Chemical Industry Co., Ltd.
20 g of yowaad2000 was added, and stirring was continued at this temperature for 2 hours. Then, after cooling to room temperature, the insolubles were filtered, and the filtrate was concentrated under reduced pressure to obtain the desired polyester acrylate as a colorless oil in a yield of 61.5 g.

Example 1 <Preparation of Solution> 1,4-butanesultone was used as a compound represented by the formula (1) or (2), and a monomer having a (meth) acrylate structure was synthesized in Synthesis Example 2. The acrylate of the polyester diol used was used.
As an electrolytic solution, LiPF6 was added to a 3/7 mixture (volume ratio) of ethylene carbonate and diethyl carbonate in an amount of 1 (m
ol / l). Each was mixed at [1,4-butane sultone] / monomer having [meth] acrylate structure] / electrolyte = 2/6/92 (weight ratio), and then mixed with 2,2′-azobis (2,4-dimethylvalero). Nitrile) was added to a concentration of 1000 ppm to prepare a solution.

<Evaluation of High Temperature Storage> 4 g of the above solution was weighed into a sample bottle, sealed, and heated in a thermostat at 50 ° C. for 2 hours to obtain a gel electrolyte. Next, the mixture was heated in a thermostat at 85 ° C. for 4 days, and the state of the gel was visually observed. Table 1 shows the results.

<Preparation of Negative Electrode> Mesocarbon microbeads manufactured by Osaka Gas Co., Ltd. (trade names: MCMB6-28, d
002 = 0.337 nm, 90 parts by weight of carbon powder having a density of 2.17 g / cm ³ ) and 10 parts by weight of polyvinylidene fluoride (PVdF) as a binder were mixed, and N-
The paste was dispersed in methylpyrrolidone to prepare a paste-like negative electrode mixture slurry. Next, this negative electrode mixture slurry was applied to a negative electrode current collector made of a 20-μm-thick strip-shaped copper foil, and dried to obtain a strip-shaped carbon negative electrode. The thickness of the negative electrode mixture after drying is 2
It was 5 μm. Furthermore, this strip-shaped electrode is 15 mm in diameter.
, And compression molded to form a negative electrode.

<Production of Positive Electrode> L manufactured by Honjo Chemical Co., Ltd.
iCoO ₂ (product name: HLC-21, average particle size 8 μm)
91 parts by weight of fine particles, 6 parts by weight of graphite as a conductive material, and polyvinylidene fluoride (PVD) as a binder
F) was mixed with 3 parts by weight to prepare a positive electrode mixture, and dispersed in N-methylpyrrolidone to obtain a positive electrode mixture slurry. This slurry was applied to a 20-μm-thick aluminum foil positive electrode current collector, dried, and compression-molded to obtain a belt-shaped positive electrode. The thickness of the positive electrode mixture after drying was 40 μm.
Thereafter, the strip-shaped electrode was punched into a disk having a diameter of 15 mm to obtain a positive electrode.

<Preparation of Battery> Using the disc-shaped negative electrode and the disc-shaped positive electrode thus obtained, a stainless steel 2
A negative electrode, a polyethylene separator, and a positive electrode were stacked in this order in a 032 size battery can, and the solution 1 was impregnated. Then, a stainless steel plate (thickness 2.4) was placed in the battery can.
mm, diameter 15.4 mm), and the battery can (lid) was caulked via a polypropylene gasket. As a result, the airtightness in the battery can be maintained, and the diameter is 20 m.
m, a button-type secondary battery having a height of 3.2 mm was obtained. This battery was heated in an oven at 50 ° C. for 2 hours to obtain a button-type gel polymer electrolyte secondary battery having a capacity of about 3.7 mAh.

<Evaluation of Initial Characteristics> The gel-type polymer electrolyte secondary battery thus obtained was charged by a constant current method of 0.37 mA, and was terminated when the battery voltage reached 4.2 V. . Discharging was performed by the 0.37 mA constant current method, and was terminated when the battery voltage reached 3.0 V.
The initial charge / discharge efficiency was calculated using the following equation. Table 1 shows the initial charge / discharge efficiency and the initial discharge capacity. Initial charge / discharge efficiency (%) = initial discharge capacity (mAh) / initial charge capacity (mAh) × 100

<Evaluation of Load Characteristics> With respect to the above-mentioned gel polymer electrolyte secondary battery, after initial charge and discharge, load characteristics were evaluated by changing discharge current. The charging was performed up to 4.2 V by the 3.7 mA constant current method, and then terminated when the charging current reached 0.185 mA at 4.2 V. Discharging was performed at constant current values of 0.74 and 7.4 mA, and was terminated when the battery voltage reached 3.0 V. 7.4m
The capacity retention ratio in the A discharge was calculated using the following equation. Table 1 shows the results. Discharge capacity (mA) at capacity retention rate (%) = 7.4 mA
h) / discharge capacity at 0.74 mA (mAh) × 10
0

Comparative Example 1 A gel polymer electrolyte battery was prepared in the same manner as in Example 1, except that 1,4-butanesultone was not used, and the initial characteristics and load characteristics were evaluated. Table 1 shows the results.

[0073]

[Table 1]

[0074]

The polymer solid electrolyte provided by the present invention has high ionic conductivity, excellent electrochemical stability, and high retention of plasticizers and alkali metal salts. ing. The film-like material is flexible, and the gel-like material has excellent liquid retention.

Accordingly, this polymer solid electrolyte can be suitably used for primary batteries, secondary batteries, capacitors, electrochemical devices such as electrochromic display devices, medical actuators, and the like.

In particular, a secondary battery containing this solid polymer electrolyte has excellent battery performance such as initial characteristics and load characteristics, and has good liquid retention properties, so that there is almost no fear of liquid leakage from the battery. It has excellent storage stability in a charged state, and has improved battery reliability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 1/06 H01B 1/06 A H01G 9/025 H01M 6/18 E 9/028 H01G 9/00 301G / / H01M 6/18 9/02 331Z (72) Inventor Nobu Enobu 580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals, Inc. (72) Inventor Shinobu Aoki 580-32, Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals F term (reference) 4J002 BG071 DE187 DE197 DH007 DK007 EV316 FD206 FD207 GQ00 5G301 CA30 CD01 5H024 AA12 FF23 5H029 AJ02 AJ15 AK02 AK03 AK05 AK16 AL01 AL02 AL06 AL07 AL08 AL11 AL12 AM16 BJ03 DJ09

Claims (10)

[Claims] 1. A polymer compound, a compound represented by the formula (1) or (2) and a group 1a or 2a of the periodic table
A polymer solid electrolyte comprising a group III metal salt. Embedded image 2. A method according to claim 1, wherein said high molecular compound is a polyether polyol, a polyester polyol, a polycarbonate polyol, and a polyester carbonate polyol. The polymer solid electrolyte according to claim 1, comprising one or more polymers of an ester compound obtained by reacting with an acid. 3. The compound represented by the formula (1) or (2) is added in an amount of 100 parts by weight of the polymer compound.
2. The composition according to claim 1, wherein the amount is 0.1 to 200 parts by weight.
Or the polymer solid electrolyte according to 2. 4. The solid polymer electrolyte according to claim 2, wherein the weight average molecular weight of the polyol compound is from 200 to 100,000. 5. The solid polymer electrolyte according to claim 1, wherein the metal salt of Group 1a or Group 2a of the periodic table is a lithium salt or a magnesium salt. 6. The metal salt of Group Ia of the periodic table, wherein the metal salt is LiP
F _6, LiBF ₄ or a polymer solid electrolyte according to any one of claims 1 to 5, characterized in that a mixture thereof. 7. The polymer solid electrolyte according to claim 1, wherein said polymer compound is a gel-like material holding a non-aqueous solvent. 8. The weight ratio of the polymer compound to the non-aqueous solvent (polymer compound) / (non-aqueous solvent) is 0.02 to 10%.
The solid polymer electrolyte according to claim 7, wherein: 9. A secondary battery comprising the polymer solid electrolyte according to claim 1. 10. A polymer solid electrolyte according to claim 1, wherein the negative electrode active material is metallic lithium, a lithium-containing alloy, a carbon material capable of doping and undoping lithium ions, and a lithium ion doping. Negative electrode and positive electrode active material containing at least one selected from the group consisting of tin oxide capable of undoping, silicon capable of doping and undoping lithium ions, and titanium oxide capable of doping and undoping lithium ions A secondary battery comprising a positive electrode containing a composite oxide of lithium and a transition metal.