JP2002033131A - Polymer solid electrolyte and secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer solid electrolyte having high ion conductivity, excellent electro-chemical stability and excellent stability in the charged state, and to provide a secondary battery using the polymer solid electrolyte. SOLUTION: This polymer solid electrolyte contains metal salt of the first Ia group of the periodic system and an acid inorganic matter in a high-molecular compound. The secondary battery uses the polymer solid electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a solid polymer electrolyte used for primary batteries, secondary batteries, capacitors and the like.
And a secondary battery using the same. More specifically,
The present invention relates to an acrylate or methacrylate polymer solid electrolyte having excellent storage stability 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 risk of liquid leakage, so that a highly reliable element can be provided, and there is also an advantage that the element itself can be reduced in size and weight.

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 discloses a cross-linked resin and an inorganic salt mainly composed 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 discloses 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. Is being done. However, the solid polymer electrolyte containing these plasticizers may become liquefied when stored in a charged state depending on the type thereof, particularly when LiPF6 is used as a metal salt. Therefore, in order to realize primary and secondary batteries that have excellent charge / discharge characteristics using a solid electrolyte and operate stably in a high-temperature environment, they have high ionic conductivity and excellent electrochemical stability. There is a demand for a polymer solid electrolyte which has excellent stability in a charged state and is inexpensive.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a solid polymer electrolyte having high ionic conductivity, excellent electrochemical stability, and excellent stability in a charged state. To the purpose. Another object of the present invention is to provide a secondary battery using such a solid polymer electrolyte.

[0009]

SUMMARY OF THE INVENTION The present invention provides a solid polymer electrolyte comprising a polymer compound containing a metal salt of Group Ia of the periodic table and an acidic inorganic substance.

The above-mentioned acidic inorganic substance is Al ₂ O ₃ or S
The solid polymer electrolyte that is an acidic inorganic substance containing iO ₂ is a preferred embodiment of the present invention.

The above-mentioned high molecular compound is characterized in that at least a part or all of the hydroxyl groups of at least one kind of polyol compound selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol and polyester carbonate polyol are converted to acrylic acid or methacrylic acid. The polymer solid electrolyte, which is a polymer of an ester compound obtained by reacting with the above, is also a preferred embodiment of the present invention.

The polymer solid electrolyte in which the metal salt of Group Ia of the periodic table is a lithium salt is also a preferred embodiment of the present invention.

The above-mentioned polymer solid electrolyte in which the polymer compound is a gel-like material holding a non-aqueous solvent is also 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 the above-mentioned polymer solid electrolyte, metallic lithium, a lithium-containing alloy, a carbon material capable of doping and undoping of lithium ions, and a doping and undoping of lithium ions as a negative electrode active material. 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.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the polymer solid electrolyte according to the present invention and each structure of a secondary battery using the same will be described. In this specification, acrylate and methacrylate are collectively referred to as (meth) acrylate.

The solid polymer electrolyte of the present invention is a solid polymer electrolyte comprising a metal compound of Group Ia of the periodic table and an acidic inorganic substance in a polymer compound.

Acidic Inorganic Substance As the compound having an acidic inorganic substance contained in the polymer electrolyte in the present invention, a compound containing Al ₂ O ₃ and SiO ₂ is desirable. Among the acidic inorganic substances, those containing Al ₂ O ₃ are most desirable, and the content is preferably 50% or more, more preferably 95% or more, based on the total weight of the acidic inorganic substances.

The average particle size of the primary particles of the acidic inorganic substance contained in the polymer electrolyte is preferably 100 nm or less,
More preferably, the thickness is 5 to 50 nm.

The amount of the acidic inorganic substance to be added is 0.001% by weight or more, preferably 0.01 to 20% by weight, more preferably 0.02% by weight, based on the total weight of the polymer electrolyte containing the same.
Desirably, it is 5% by weight.

Polymer Compounds Examples of the above-mentioned polymer compounds include polyether (polyether polyol, polycarbonate polyol, polyester polyol, and polyester carbonate polyol) obtained by converting some or all of the hydroxyl groups to (meth) acrylic acid ester. Examples thereof include polymers of polymerizable monomers such as (meth) acrylate, polycarbonate (meth) acrylate, polyester (meth) acrylate, and polyester carbonate (meth) acrylate. One of these polymerizable monomers may be used, or two or more thereof may be used.

Here, the polyol means an alcohol having 2 or more hydroxyl groups, and the polyether polyol, the polycarbonate polyol or the polyester polyol has a weight average molecular weight of 200 to 100,00.
0, preferably 250 to 20,000, more preferably 300 to 10,000. In addition, a weight average molecular weight is 500-100,000, or 1,000-2.
A polyol of 000 can sufficiently achieve the object of the present invention.

The above-mentioned polyether polyol can be obtained by polymerizing an alkylene oxide or adding an alkylene oxide to a polyhydric alcohol. Examples of the alkylene oxide include ethylene oxide, propylene oxide, oxetane, tetrahydrofuran and the like, and 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. Specific examples of polyether polyols, polyethylene glycol,
Examples thereof include polypropylene glycol and polybutylene glycol.

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. Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,4
-Butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,3-bis (2
-Hydroxyethoxy) benzene, 1,4-bis (2-
(Hydroxyethoxy) benzene, neopentyl glycol, 2-methyl-1,8-octanediol, 1,9-
Nonanediol, 1,4-cyclohexanediol,
Diols such as 1,4-cyclohexanedimethanol,
Also, trimethylolpropane, trimethylolethane,
Pentaerythritol, ditrimethylolpropane, dipentaerythritol, glycerin, polyols such as sorbitol, and a hydroxyl group obtained by adding 1 to 5 equivalents of ethylene oxide, propylene oxide, or other alkylene oxide to the hydroxyl group of these polyols. Alcohols and the like. These polyhydric alcohols may be used alone or in combination of two or more.

As the carbonic diester, dimethyl carbonate,
Diethyl carbonate, diisopropyl carbonate, ethylene carbonate, propylene carbonate and the like,
These may be used alone or in combination of two or more.

The above polyester polyol can be synthesized by polycondensation of a hydroxycarboxylic acid or a lactone or by polycondensation of a polyhydric alcohol and a polycarboxylic acid. Here, 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-caprolactone and the like. 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 and the like, and polyols such as trimethylolpropane, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, glycerin, sorbitol and the like can be mentioned.

Examples of the polycarboxylic acid 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 When a polymer compound comprising one or more monomers containing an acrylate group and / or a methacrylate group, which is preferably used in the present invention, is produced, the polymer has a weight average It is preferable that the molecular weight is 10,000 or more. In particular, when a gel electrolyte is used, it is important to use a high molecular weight crosslinked polymer having low solubility in a solvent in the electrolytic solution. The production can be carried out under almost the same method and conditions as ordinary poly (meth) acrylate.

The polymerization is carried out by irradiating ultraviolet rays or radiation or heating in the presence of a monomer containing an acrylate group and / or a methacrylate group and, if necessary, other copolymerizable monomers.

Examples of the other copolymerizable monomers include vinyl monomers and vinylidene monomers.
More specifically, vinyl esters, vinyl ethers,
(Meth) acrylates, allyl ethers and allyl esters are preferred. As specific examples, 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-
(Di-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, vinyl fluoride, vinylidene fluoride, acrylonitrile, vinyl cyanoacetate, allylamine, isopropylacrylamide vinylene carbonate, and maleic anhydride.

In the case of polymerization by ultraviolet irradiation, a photosensitizer can be used, and examples of such a photosensitizer include benzophenone, acetophenone, 2,2-dimethoxy-2-phenylacetophenone and the like. .
In the case of polymerization by a heating method, a thermal polymerization initiator can be used, and depending on the polymerization mode, peroxides such as benzoyl peroxide and peroxydicarbonate,
Azo compounds such as 2′-azobisisobutyronitrile,
Nucleophiles such as alkali metals and electrophiles such as Lewis acids can be used alone or in combination.

When a solvent is used, examples thereof include alcohols such as methanol, ethanol, propanol, butanol and ethylene glycol; halogenated hydrocarbons such as dichloromethane, chloroform and dichloroethane; and aromatic hydrocarbons such as benzene, toluene and xylene. Hydrogens, saturated hydrocarbons such as hexane, heptane, decane and cyclohexane, ethers such as diethyl ether and tetrahydrofuran (THF), ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl Carbonates such as carbonate, ethyl acetate, propyl acetate, butyl acetate, γ-butyrolactone, δ-valerolactone, ε
Esters such as caprolactone. At this time, the weight ratio of the polymer compound and the non-aqueous solvent is (polymer compound) / (non-aqueous solvent) = 0.02 to 10, preferably 0.04 to 1.

After polymerization, the resulting polymer is in the form of a powder,
It is obtained in the form of a 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, the polymer can be used as a film-like or powder-like polymer from which the solvent has been removed by drying.

Polymer Solid Electrolyte In the polymer solid electrolyte according to the present invention, the polymer compound contains a metal salt of Group Ia of the periodic table and the acidic inorganic substance. In a preferred embodiment, the polymer produced by irradiation with ultraviolet light or radiation or heating in the presence of one or more monomers containing an acrylate group and / or a methacrylate group, or other copolymerizable monomers is used. , A solid polymer electrolyte containing an acidic inorganic substance and a metal salt of Group Ia of the periodic table.

Examples of the metal salt of Group Ia of the periodic table include lithium
Compounds such as sodium, potassium, etc.
The metal salt concentration in the electrolyte is 0.1 to 10 mol / l, preferably
Or a concentration of 0.5 to 2 mol / l in the solid electrolyte.
It is desirable that they are rare. Specific examples of metal salts include:
LiPF₆, LiBF_Four, LiClO_Four, LiAsF₆, Li _TwoSi
F₆, Li [(C_TwoF_Five)_ThreePF_Three] And other lithium salts
I can do it. In addition, a lithium salt represented by the following general formula is also used.
Can be used. LiOSO_TwoR¹, LiN (SO_TwoR^Two)
(SO_TwoR^Three), LiC (SO_TwoR^Four) (SO_TwoR^Five) (SO_TwoR⁶),
Lin (SO_TwoOR⁷) (SO_TwoOR⁸) (Where R¹~ R
⁸May be the same or different from each other,
(1-8). these
Lithium salts may be used alone or in combination of two or more.
They may be used in combination.

Of these, LiPF ₆ , LiBF ₄ , Li
[(C ₂ F ₅ ) ₃ PF ₃ ], LiOSO ₂ R ¹ , LiN (SO ₂ R
² ) (SO ₂ R ³ ), LiC (SO ₂ R ⁴ ) (SO ₂ R ⁵ ) (SO
^{_{2 R 6), LiN (SO}} 2 OR 7) (SO 2 OR 8) it is preferred, more preferably LiPF _6.

The solid electrolyte is produced by uniformly mixing a polymer prepared from one or more monomers containing an acrylate group and / or a methacrylate group with an acidic inorganic substance and a metal salt of Group Ia of the Periodic Table. Alternatively, the polymerization can be carried out by, for example, a method in which the monomer, the acidic inorganic substance and the metal salt of Group Ia of the Periodic Table are uniformly mixed during the polymerization, and then the polymerization is advanced. 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.

For example, one or more monomers having an acrylate group and / or a methacrylate group, a compound having an acidic inorganic substance, a metal salt of Group Ia of the periodic table, and, if necessary, a solvent are added. The polymerization and gelation can be promoted by applying the mixture on a flat substrate and then irradiating with light, irradiating with radiation, or heating. Thus, the thickness is 0.1 to 1
A 000 μm solid electrolyte thin film 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.

The solid polymer electrolyte according to the present invention may contain a non-aqueous solvent such as a carbonate ester in addition to the above-mentioned polymer compound and a metal salt of Group Ia of the periodic table. . At this time, the weight ratio of the polymer compound and the non-aqueous solvent is (polymer compound) / (non-aqueous solvent) = 0.02 to 10,
Preferably, it is 0.04-1. 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. Etc. may be taken.

As the non-aqueous solvent, carbonate esters or lactones can be suitably used. Examples of carbonates include ethylene carbonate, propylene carbonate,
Dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, chain or cyclic carbonate such as dibutyl carbonate,
Examples of lactones include γ-butyrolactone, δ-
Valerolactone, ε-caprolactone and the like.

The solid polymer electrolyte according to the present invention has excellent liquid retention properties in a state containing a non-aqueous 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 electrolyte for 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 polymer solid electrolyte disposed therebetween.

As the negative electrode active material, metallic lithium, a lithium-containing alloy, a material capable of doping and undoping lithium ions, and the like can be used. Such a material capable of doping and undoping lithium ions can be appropriately selected from carbon materials, tin oxide, silicon, titanium oxide, transition metal nitrides, 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 , TiS ₂ ,
Transition metal oxides or sulfides such as MnO ₂ and V ₂ O ₅ , LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , L
composite oxides composed of lithium and a transition metal such as iNiO ₂ and LiNi _X Co _(1-X) O ₂ , polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene,
Examples include conductive polymer compounds such as dimercaptothiadiazole / polyaniline complex, 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 for 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 a battery manufacturing process including a 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, a polymer compound, a metal of Group Ia of the periodic table is used instead of the electrolytic solution. It is also possible to adopt a method of adding and impregnating a solution comprising a salt and a non-aqueous solvent followed by gelation. In any case, by using the above-described 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.

[0048]

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, a thermometer and a 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 3 (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. Next, at 50 ° C, it is a solid base product of Kyowa Chemical Industry Co., Ltd.
Add 20 g of Kyowaad 2000, and add 2 g at this temperature.
Stirring was continued for hours. Then, after cooling to room temperature, the insoluble matter was filtered, and the filtrate was concentrated under reduced pressure to obtain 61.5 g of the desired polyester acrylate as a colorless oil.

Example 1 A polymer electrolyte was prepared using the monomers described in Synthesis Example 2, and a button-type battery containing the polymer electrolyte was prepared. The battery characteristics were evaluated.

<Preparation of Monomer Electrolyte> Next, ethylene carbonate (EC) and diethyl carbonate (DE)
C) and EC: DEC = 58: 42 (weight ratio) to obtain a non-aqueous solvent, and LiPF ₆ as an electrolyte was dissolved in the non-aqueous solvent, and the electrolyte concentration was 1.0 (mol /
A non-aqueous electrolyte was prepared so as to satisfy 1). Further, as an acidic inorganic substance, Al ₂ O ₃ (manufactured by Texa, primary particle size 21
nm) was added in an amount of 1% by weight with respect to the nonaqueous electrolyte.

The monomer of Synthesis Example 2 and the above-mentioned acidic inorganic substance A
After mixing with a non-aqueous electrolyte to which l ₂ O ₃ was added at a ratio of 1:10 (weight ratio), AIBN as a polymerization initiator was added so as to have a concentration of 2000 ppm with respect to the monomer electrolyte. Preparation of monomer electrolyte solution containing agent

<Preparation of Negative Electrode> Mesocarbon microbeads (trade name: MCMB6-28, d, manufactured by Osaka Gas Co., Ltd.)
002 = 0.337 nm, density 2.17 g / cm ³ ) 90 parts by weight of carbon powder 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 electrode is 15 mm in diameter.
, And compression molded to form a negative electrode.

<Preparation 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> The thus obtained monomer electrolyte solution, disk-shaped negative electrode and disk-shaped positive electrode were prepared as an electrolyte, a negative electrode and a positive electrode, and a microporous polypropylene film having a diameter of 16 mmΦ was prepared as a separator. . The separator was impregnated with the monomer electrolyte solution, and a negative electrode, a separator impregnated with the monomer electrolyte solution, and a positive electrode were laminated in the order of 2032 in a stainless steel battery can. Then, a stainless steel plate (thickness 2.4) was placed in the battery can.
mm, diameter 15.4mm), and further caulked the battery can (lid) via a polypropylene gasket,
It was left in an oven at 50 ° C. for 10 hours. As a result, a button-type gel-type polymer electrolyte secondary battery having a diameter of 20 mm and a height of 3.2 mm was obtained.

<Measurement Results> The discharge capacity of the thus obtained gel polymer electrolyte secondary battery was measured at room temperature. In this example, the current direction in which the negative electrode was doped with Li + was charged, and the current direction in which the negative electrode was undoped was discharge. The charging was performed by a 4.2 V, 1 mA constant current, constant voltage charging method, and was terminated when the charging current became 50 μA or less. Discharge was performed at a constant current of 1 mA up to 2.75 V. As a result of repeating the above-described charge and discharge for 10 cycles, the charge and discharge efficiency at the 10th cycle was 99%, and the discharge capacity was 130 (mAh / g) based on the amount of the positive electrode active material.

Further, as a result of disassembling and observing the coin cell having been charged and discharged for 10 cycles, no liquid was present in the battery, there was no liquid leakage, and the gel electrolyte was maintained at a high level in the battery. It was confirmed that the liquid was maintained.

Comparative Example 1 A button-type gel polymer electrolyte secondary battery was produced in the same manner as in Example 1, except that Al ₂ O ₃ was not added to the monomer electrolyte. As a result, the charge / discharge efficiency at the 10th cycle was 98%, and the discharge capacity was 125 (mAh / g) based on the amount of the positive electrode active material. As a result of observation after disassembly, a liquid was present in the battery. It was confirmed that.

[0060]

The polymer solid electrolyte according to the present invention has high ionic conductivity, is also excellent in electrochemical stability, and has improved plasticizer and alkali metal salt retention performance. The film-like material is flexible, and the gel-like material has excellent liquid retention and stability in charge and discharge.

Therefore, the 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 charge / discharge characteristics, and has good liquid retention, so that there is almost no fear of liquid leakage from the battery.
Furthermore, the storage stability during charging is excellent, and the reliability of the battery is improved.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01G 9/035 H01G 9/00 301D 9/028 9/02 311 H01M 6/18 331G (72) Inventor Takeshi Ishitoku Chiba 580-32, Takuji, Nagaura-shi, Sodegaura-shi Mitsui Chemicals, Inc. (72) Inventor: Eishin Nogi 580-32, Takuji, Nagaura, Sodegaura-shi, Chiba Pref. 580-32, Takuji, Nagaura, Sodegaura-shi Mitsui Chemicals, Inc. (72) Inventor Masahiro Toriida 580-32, Takuji, Nagaura, Sodegaura, Chiba Pref. Mitsui Chemicals, Inc. 580-32, Takuji, Nagaura-shi, Sodegaura-shi, Pref. Mitsui Chemicals, Inc. F-term (reference) 4J027 AB03 AB10 AB15 AB16 AB17 AB18 AB19 AB23 AB24 AB25 AB28 AC03 AC04 AC06 AH03 BA04 BA05 BA07 BA13 BA14 CB10 CC02 CC03 CC05 CD00 5G301 CA02 CA12 CA30 CD01 5H024 AA02 AA12 FF23 FF38 HH00 5H029 AJ04 AJ12 AK02 AK03 AK05 AK16 AL01 AL02 AL06 AL07 AL08 AL12 AM0 0 AM02 AM03 AM04 AM07 AM16 DJ09 HJ00

Claims (12)

[Claims] 1. A solid polymer electrolyte comprising a polymer compound containing a metal salt of Group Ia of the Periodic Table and an acidic inorganic substance. 2. The method according to claim 1, wherein said acidic inorganic substance is Al ₂ O ₃ or S
The polymer solid electrolyte according to claim 1, characterized in that the acidic inorganic substance containing iO _2. 3. The polymer according to claim 2, wherein the acidic inorganic substance is an acidic inorganic substance containing 99.5% or more of Al ₂ O _{3 based} on the total weight of the acidic inorganic substance. Solid electrolyte. 4. An average particle diameter of primary particles of said acidic inorganic substance is 5
The polymer solid electrolyte according to any one of claims 1 to 3, wherein the thickness is from 50 to 50 nm. 5. The polymer solid electrolyte according to claim 1, wherein the content of the acidic inorganic substance is 0.001 to 20% by weight based on the total weight of the polymer electrolyte. 6. The polymer compound according to claim 1, wherein part or all of the hydroxyl groups of at least one polyol compound selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, and polyester carbonate polyols. The polymer solid electrolyte according to any one of claims 1 to 5, which is a polymer of an ester compound obtained by reacting with acrylic acid or methacrylic acid. 7. The polymer solid electrolyte according to claim 6, wherein the weight average molecular weight of the polyol compound is from 200 to 100,000. 8. The polymer solid electrolyte according to claim 1, wherein the metal salt of Group Ia of the periodic table is a lithium salt. 9. The metal salt of Group Ia of the periodic table is LiP
9. The polymer solid electrolyte according to claim 8, wherein F ₆ is F ₆ . 10. The polymer solid electrolyte according to claim 1, wherein said polymer compound is a gel-like material holding a non-aqueous solvent. 11. A secondary battery comprising the polymer solid electrolyte according to claim 1. 12. A polymer solid electrolyte according to claim 1, wherein the negative electrode active material is lithium metal, 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.