JP2005142024A - Solid polyelectrolyte and secondary battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polyelectrolyte excellent in reliability and safety and capable of realizing a high ionic conductance, and a secondary battery using the solid polyelectrolyte. <P>SOLUTION: This solid polyelectrolyte is characterized by containing cold fusing salt having compatibility with water and room temperature molten salt not having compatibility with water. It is desirable that the solid polyelectrolyte should contain a cross linking agent having two or more radical polymeric functional groups, and the polyelectrolyte can contain a nonaqueous solvent. At least one of the room temperature molten salt having compatibility with water and the room temperature melten salt not having compatibility with water is composed of an ammonium component having radical polymeric functional groups and an acid component having radical polymeric functional groups. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polymer solid electrolyte and a secondary battery using the polymer solid electrolyte.

  In order to improve characteristics such as long-term reliability in a secondary battery, a method of making an electrolytic solution non-liquefied has been studied, and one of them is a polymer solid electrolyte. Polymer solid electrolytes are often classified into two types for convenience. One is a method using a gel electrolyte in which the electrolyte is gelled with a polymer compound and the fluidity of the electrolyte is lost. One method is to use an electrolyte that uses no organic solvent at all, or an organic solvent with a low boiling point when synthesizing a polymer electrolyte, and then an all solid-state solid electrolyte that removes the organic solvent with a low boiling point by heating or the like. is there.

As the gel electrolyte, for example, a porous synthetic resin film and / or a synthetic fiber nonwoven fabric is impregnated with a liquid mixture comprising a monomer or a macromer, a non-aqueous solvent, and an inorganic ion salt, and then the liquid mixture is gelled. A semi-solid polymer electrolyte membrane has been proposed (see, for example, Patent Document 1), and an ion conductivity of 10 ⁻⁴ S / cm has been achieved, but the level of reliability is not sufficient. On the other hand, as an all solid-type solid electrolyte, for example, an imidazolium-based molten salt electrolyte containing an N-alkylimidazolium salt as an active ingredient has been proposed (see, for example, Patent Document 2), and an ionic conductivity of 10 ⁻⁷ S. / Cm is achieved, but these ionic conductivities are not sufficiently satisfactory in battery performance.

On the other hand, it is also highly reliable to use a room temperature molten salt that is liquid at room temperature but has little volatility and that is flame retardant or nonflammable as a molten salt electrolyte for a polymer solid electrolyte. Since it can be expected that a battery can be realized, it has been actively studied (for example, see Non-Patent Document 1). The electrolyte described in this document is forced to greatly reduce the ionic conductivity by incorporating a molten salt into the polymer, the ionic conductivity of the resulting polymer electrolyte is not a satisfactory level, Furthermore, it is desired to improve the ionic conductivity.
JP-A-2-82457 Japanese Unexamined Patent Publication No. 2000-11753 (page 4, table 2) Electrochimica Acta 46, 1407-1411 (2001)

  An object of the present invention is to solve the above-mentioned problems, to provide a polymer solid electrolyte that is excellent in reliability and can realize high ionic conductivity, and to provide a battery using the polymer solid electrolyte. It is said.

  As a result of intensive studies in order to achieve the above object, the inventors of the present invention have used a solid polymer electrolyte having high ionic conductivity by using two or more kinds of room temperature molten salts having different water compatibility. It was found that by using such a solid polymer electrolyte for a secondary battery, a secondary battery excellent in reliability, safety and battery characteristics can be realized, and the present invention has been completed.

The present invention is a solid polymer electrolyte comprising a room temperature molten salt that is compatible with water and a room temperature molten salt that is not compatible with water.
The polymer solid electrolyte of the present invention preferably contains a cross-linking agent having two or more radical polymerizable functional groups, and can contain a non-aqueous solvent.
At least one of the room temperature molten salt compatible with water and the room temperature molten salt not compatible with water has an ammonium component having a radical polymerizable functional group and a radical polymerizable functional group. It is preferable that it is comprised from an acid component.
The present invention also provides a secondary battery comprising the polymer electrolyte as a constituent element.

  ADVANTAGE OF THE INVENTION According to this invention, the polymer solid electrolyte which has high ionic conductivity can be provided, and the secondary battery excellent in reliability, safety | security, and a battery characteristic can be provided by using this.

The present invention is a solid polymer electrolyte comprising a room temperature molten salt that is compatible with water and a room temperature molten salt that is not compatible with water, and has room temperature melting having a greatly different affinity for water. High ionic conductivity can be obtained by using a salt in combination. The polymer solid electrolyte of the present invention is extremely low in volatility even though it is liquid at room temperature, and further, by developing the properties of room temperature molten salt having the property of flame retardancy or incombustibility, The secondary battery can exhibit excellent reliability, safety, and battery characteristics.
In addition, in this invention, normal temperature refers to the temperature considered that a battery normally operate | moves, and means the temperature range of -40 degreeC to 120 degreeC.

  The room temperature molten salt used in the present invention is composed of a cation part and an anion part, and these are cation having or not having a polymerizable functional group, an anion having or not having a polymerizable functional group. More specifically, a molten salt that is a combination of a cation having no polymerizable functional group and an anion having no polymerizable functional group, a cation having no polymerizable functional group, and a polymerizable functional group A molten salt type monofunctional salt monomer which is a combination with an anion having a molten salt type, a molten salt type monofunctional salt monomer which is a combination of a cation having a polymerizable functional group and an anion having no polymerizable functional group, Examples thereof include a molten salt type polyfunctional salt monomer which is a combination of a cation having a polymerizable functional group and an anion having a polymerizable functional group. Among these molten salts, those corresponding to room-temperature molten salts that are incompatible with water and room-temperature molten salts that are compatible with water are affected by the type and size of ions and are determined by the combination of ions.

  Examples of the cationic moiety having no polymerizable functional group include, for example, trimethylethylammonium ion, trimethylpropylammonium ion, trimethylbutylammonium ion, triethylmethylammonium ion, triethylpropylammonium ion, triethylbutylammonium ion, trimethylbenzylammonium ion and Tetraalkylammonium ions such as triethylbenzylammonium ion, dialkylimidazolium ions such as 1-ethyl-3-methylimidazolium ion and 1-methyl-3-ethylimidazolium ion, 1,2,3-trimethylimidazolium ion, and Trialkylimidazolium ions such as 1,2-dimethyl-3-ethylimidazolium ion, N-methylpyridinium Pyridinium ions such as muon, N-ethylpyridinium ion and N-propylpyridinium ion, pyrazolium ion, pyrrolinium ion, pyrrolidinium ion, piperidinium ion, and the like. (For example, chloride or bromide) can be used.

  Examples of the cation moiety having a polymerizable functional group include 2-ethyltrimethylammonium ion methacrylate, 3-acrylamidopropyltrimethylammonium ion, 2-ethyltrimethylammonium acrylate ion, 3-methacrylamidopropyltrimethylammonium ion, Dimethylaminoethyl benzyl methacrylate ion, N, N-dimethyl-N-di-2-propenyl-2-propen-1-aminium ion, diallylmethylphenylammonium ion, N-methyl-N, N-di-2- Propenyl-1-dodecanaminium ion, diallylbis (cyclohexylmethyl) ammonium ion, diallyldimethyl (2-methylallyl) ammonium ion, N-methyl-N, N-di-2-propenylbenzene meta Ion, N-methyl-N, N-di-2-propenyl-1-dodecanaminium ion, allyldimethyl (1-methyl-2-butenyl) ammonium ion, diacetyl diallylammonium ion, N-methyl-N, N-di-2-propenyl-2-propene-1-aminium ion, 2-ethyl dimethylhexyl ammonium ion, 2-ethyl dimethyl heptyl ammonium ion, 2-ethyl dimethyl octyl ammonium ion, 2- Ethyl dimethyl nonyl ammonium ion, 2-ethyl dimethyl decyl ammonium ion, 2-ethyl dimethyl dodecyl ammonium ion, 2-ethyl dimethyl eicosyl ammonium ion, 2-a Ethyl dimethyl hexyl ammonium ion, 2-dimethylethyl heptyl ammonium acrylate, 2-ethyl dimethyl octyl ammonium acrylate, 2-ethyl dimethyl nonyl ammonium acrylate, 2-ethyl dimethyl decyl ammonium acrylate, 2- Ethyl dimethyl dodecyl ammonium ion, 2-ethyl dimethyl eicosyl ammonium ion, 3-methacrylamidopropyldimethylhexylammonium ion, 3-methacrylamidopropyldimethylheptylammonium ion, 3-methacrylamidopropyldimethyloctylammonium ion, 3 -Methacrylamidopropyldimethylnonyl ammonium ion, 3-methacrylamideamidopropyl Methyl decyl ammonium ion, 3-methacrylamidopropyl dimethyl dodecyl ammonium ion, 3-methacrylamido propyl dimethyl eicosyl ammonium ion, 3-acrylamido propyl dimethyl hexyl ammonium ion, 3-acrylamido propyl dimethyl heptyl ammonium ion, 3-acrylamido propyl dimethyl octyl Ammonium ion, 3-acrylamidopropyldimethylnonylammonium ion, 3-acrylamidopropyldimethyldecylammonium ion, 3-acrylamidopropyldimethyldodecylammonium ion, 3-acrylamidopropyldimethyleicosylammonium ion, methylstyryldimethylhexylammonium ion, methylstyryldimethyl Heptyl ammonium ion, methyl styryl dimethyl octyl ammonium ion, methyl styryl dimethyl nonyl ammonium ion, methyl styryl dimethyl decyl ammonium ion, methyl styryl dimethyl dodecyl ammonium ion, methyl styryl dimethyl eicosyl ammonium ion, etc. These halides (for example, chloride) can be used.

Examples of the anion portion having no polymerizable functional group include Cl ⁻ , Br ⁻ , I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) _{2. ^{-, N (C 2 F 5}} SO 2) 2 -, C (CF 3 SO 2) 3 -, C (C 2 F 5 SO 2) 3 - is like, in the synthesis of ambient temperature molten salt, the inorganic Metal salts (eg lithium salts) can be used.

  The anionic moiety having a polymerizable functional group is preferably a carboxylate ion or a sulfonate ion having a radical polymerizable functional group, such as 2-vinylbenzenesulfonic acid, 3-vinylbenzenesulfonic acid, 4-vinylbenzene. Sulfonic acid, 2-methyl-1-pentene-1-sulfonic acid, 1-octene-1-sulfonic acid, 4-vinylbenzenemethanesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, acrylic acid, Methacrylic acid, phthalic acid-2- (methacryloyloxy) ethyl, phthalic acid-3- (methacryloyloxy) ethyl, phthalic acid-4- (methacryloyloxy) ethyl, phthalic acid-2- (acryloyloxy) ethyl, phthalic acid- 3- (acryloyloxy) ethyl, phthalic acid-4- (acryloylo) (Ii) Anions composed of ethyl, 2-vinylbenzoic acid, 3-vinylbenzoic acid, 4-vinylbenzoic acid and the like. In the synthesis of room temperature molten salts, these inorganic metal salts such as lithium salts and silver salts Can be used.

As a method for synthesizing a room temperature molten salt used in the present invention, a general method such as an ion exchange method can be applied. For example, a cationic halide having no polymerizable functional group (for example, 1-ethyl-3-methylimidazolium bromide) or a cationic halide having the polymerizable functional group (for example, methylstyryldimethyldodecyl ammonium chloride). And an anionic inorganic metal salt having no polymerizable functional group (for example, LiN (SO ₂ CF ₃ ) ₂ , LiPF _6, etc.), or an anionic inorganic metal salt having the polymerizable functional group (for example, , 4-vinylbenzenemethanesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid metal salt, etc.) were dissolved in a solvent such as water, and ion exchange was performed to separate the soluble and insoluble components. Later, a method for removing the solvent is applicable.

Further, in the present invention, at least one of the room temperature molten salt having compatibility with water and the room temperature molten salt having no compatibility with water is preferably a room temperature molten salt type salt monomer, In particular, those obtained from an ammonium component having a radical polymerizable functional group and an acid component having a radical polymerizable functional group are preferred.
As a method for synthesizing such a room temperature molten salt type salt monomer, in the method for synthesizing a room temperature molten salt, an inorganic metal salt of an anion having the polymerizable functional group (for example, sulfonic acid having a radical polymerizable functional group, Or a silver salt of a carboxylic acid) and a cation halide having a polymerizable functional group (for example, a halide of an ammonium salt containing a radical polymerizable functional group). The synthesis method is not particularly limited.

The polymer solid electrolyte of the present invention contains a crosslinking agent having two or more radically polymerizable functional groups in addition to the room temperature molten salt, thereby forming a polymer network in the polymerization and improving the thermal stability.
Moreover, it can be set as a gel electrolyte by including a non-aqueous solvent. In general, a gel electrolyte exhibits high ionic conductivity as compared with an all solid electrolyte, and excellent battery characteristics can be expected.

  Examples of the crosslinking agent having two or more radically polymerizable functional groups used in the present invention include N, N′-methylenebisacrylamide, 1,8-nonadiene, 1,13-tetradecadiene, and 1,4-butanediol. Divinyl ether, tetraethylene glycol dimethacrylate, tetraethylene glycol diacrylate, triethylene glycol divinyl ether, diethylene glycol divinyl ether, diethylene glycol diacrylate, diethylene glycol dimethacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol Koji acrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane trimethacrylate Trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, etc. Can be mentioned.

  Examples of the non-aqueous solvent used in the present invention include cyclic carbonates such as ethylene carbonate and propylene carbonate, chain carbonates such as ethyl methyl carbonate, diethyl carbonate, and dimethyl carbonate, dimethoxyethane, tetrahydrofuran, N-methyl- Examples include 2-pyrrolidone and γ-butyrolactone.

In addition to the above components, a lithium salt is used for the polymer solid electrolyte of the present invention. For example, LiPF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiBF ₄ , LiAsF ₆ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) _3, etc., and these may be used alone or in combination of two or more.

  As a compounding ratio of each component in the polymer solid electrolyte of the present invention, for example, a room temperature molten salt having no compatibility with water is preferably 3 mmol / L to 2 mol / L, and preferably 10 mmol / L to 1 mol / L. More preferably, the room temperature molten salt having compatibility with water is preferably 3 mmol / L to 2 mol / L, more preferably 10 mmol / L to 1 mol / L, and the crosslinking agent having two or more radical polymerizable functional groups is 3 mmol / L to 500 mmol / L are preferred, 5 mmol / L to 300 mmol / L are more preferred, and the lithium salt is preferably 10 mmol / L to 3 mol / L, more preferably 200 mmol / L to 2 mol / L.

  The solid polymer electrolyte of the present invention is formed by polymerization. As the polymerization method, known polymerization methods such as radical polymerization, ionic polymerization, coordination polymerization, and addition polymerization can be used, and the polymerization operation is simple. Although radical polymerization is preferable, it is not particularly limited. As a method for performing radical polymerization, a method of applying heat, a method of irradiating light in the visible / ultraviolet region, a method of irradiating radiation such as an electron beam, and the like can be used. Moreover, it is also possible to add a polymerization initiator as needed.

  Examples of the polymerization initiator used for the polymerization of the solid polymer electrolyte of the present invention include, in the case of thermal polymerization, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-isobutyronitrile). ), Azo polymerization initiators such as 2,2′-azobis (2,4-dimethylvaleronitrile), and peroxide polymerization initiators such as benzoyl peroxide, dicumyl peroxide, and diisopropyl peroxycarbonate. It is done. Examples of the polymerization initiator in the case of photopolymerization include acetophenone, benzophenone, 2,2-dimethoxy-2-phenylacetophenone, and the like. In the blending ratio of each component in the polymer solid electrolyte, the polymerization initiator is desirably 3 mmol / L to 100 mmol / L.

As an example of the synthesis method of the solid polymer electrolyte of the present invention, examples of synthesis by heating are as follows. First, a room temperature molten salt that is not compatible with water, a room temperature molten salt that is compatible with water, and a lithium salt If necessary, a monomer electrolyte solution is prepared by mixing a non-aqueous solvent such as a crosslinking agent having two or more radical polymerizable functional groups, a polymerization initiator, and a carbonate ester.
Next, the monomer electrolyte solution obtained above is stirred at room temperature to obtain a uniform solution 1. In parallel with the preparation of Solution 1, an azo polymerization initiator such as azobisisobutyronitrile or a peroxide polymerization initiator such as benzoyl peroxide is added to a non-aqueous electrolyte (lithium salt in a non-aqueous solvent). In solution, add to solution 1 and stir to obtain solution 2. The solution 2 obtained in this way is heated in an oven at 60 to 80 ° C. for about 5 minutes to 2 hours, so that a room temperature molten salt that is not compatible with water and a room temperature melt that is compatible with water A polymer solid electrolyte containing a salt, a crosslinking agent having two or more radically polymerizable functional groups, and a non-aqueous solvent is obtained.
The above method is a method that can be applied to a gel electrolyte, but in the case of an all solid electrolyte, an alcohol such as methanol is added instead of a carbonate as a non-aqueous solvent, if necessary, and then the solvent is used. It is possible to remove it.

  The secondary battery of the present invention is composed of a polymer electrolyte containing a room temperature molten salt that is not compatible with water and a room temperature molten salt that is compatible with water. In addition, for example, it is constituted by a positive electrode, a negative electrode, or the like.

In the production of the positive electrode and the negative electrode, an active material is used. As an active material for the positive electrode, a transition metal oxide containing lithium has a high energy density and is excellent in reversible desorption of lithium ions. Preferably, for example, a lithium cobalt oxide such as LiCoO ₂ , a lithium manganese oxide such as LiMn ₂ O ₄ , a lithium nickel oxide such as LiNiO ₂ , or a mixture thereof or a part of nickel in LiNiO ₂ may be cobalt or manganese. And the like substituted. Examples of the negative electrode active material include carbon-based materials that can insert and desorb lithium ions, such as natural graphite, artificial graphite, mesocarbon microbeads, and graphite.

Below, the example of the preparation method is demonstrated about the polymer solid electrolyte secondary battery of this invention. First, LiCoO ₂ as a positive electrode active material, graphite as a conductive agent, and poly (vinylidene fluoride) as a binder are mixed to prepare a positive electrode mixture. This positive electrode mixture is mixed with N-methyl-2-pyrrolidone. Disperse the mixture into a slurry-like positive electrode mixture. This positive electrode mixture is uniformly applied to both surfaces of an aluminum foil having a thickness of 20 μm used as a positive electrode current collector, dried, and then compression molded with a roll press to obtain a positive electrode.

  Next, pulverized graphite powder as a negative electrode active material and poly (vinylidene fluoride) as a binder are mixed to prepare a negative electrode mixture. This negative electrode mixture is placed in N-methyl-2-pyrrolidone. Disperse to obtain a slurry-like negative electrode mixture. This negative electrode mixture is uniformly applied on both sides of a 15 μm thick copper foil used as a negative electrode current collector, dried, and then compression molded with a roll press to obtain a negative electrode.

The negative electrode and the positive electrode obtained as described above are brought into close contact with each other through a separator made of a polyethylene microporous film having a thickness of 25 μm, and wound to form an electrode wound body. The electrode wound body is insulated. While enclosing in the exterior film which consists of material, the monomer electrolyte solution obtained above is inject | poured in an exterior film.
Next, the outer peripheral edge of the exterior film is sealed, the positive electrode terminal and the negative electrode terminal are sandwiched between the openings of the exterior film, and the electrode winding body is sealed in the exterior film under reduced pressure. A polymer solid electrolyte secondary battery is obtained by heating it at a temperature of 60 to 80 ° C. for 5 minutes to 2 hours.
Thus, according to the present invention, the polymer solid electrolyte is directly polymerized in the secondary battery after the assembly of the secondary battery by using the monomer electrolyte solution without preparing the polymer solid electrolyte in advance. can do.

EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited at all by this.
Table 1 shows a list of room temperature molten salts used in this example. The compound shown in this table indicates a room temperature molten salt composed of a corresponding cation part and anion part. Table 1 also shows the results of compatibility with water.

<Synthesis Method of Compound 1>
18.3 g of methylstyryldimethyldodecyl ammonium chloride and 214.4 g of LiN (SO ₂ CF ₃ ) ₂ are dissolved in 300 ml of water. When the mixture was stirred at room temperature, Compound 1 insoluble in water was produced and separated from water as the reaction proceeded. The fractionated Compound 1 was washed with water several times, and then water was removed with an evaporator, followed by vacuum drying to obtain 22.6 g of dehydrated Compound 1. It was confirmed that the produced compound 1 was synthesized by H-NMR.

<Synthesis Method of Compound 2>
Compound 2 was obtained in the same manner as Compound 1 except that 9.5 g of lithium 4-vinylbenzenesulfonate was used in place of LiN (SO ₂ CF ₃ ) ₂ .

<Synthesis Method of Compound 3>
Compound 3 was obtained in the same manner as Compound 1 except that 9.6 g of 1-ethyl-3-methylimidazolium bromide was used instead of methylstyryldimethyldodecylammonium chloride.

<Synthesis Method of Compound 4>
To a 150 ml aqueous solution in which 18.3 g of methylstyryldimethyldodecyl ammonium chloride was dissolved, a 150 ml aqueous solution in which 12.6 g of AgPF ₆ was dissolved was added with stirring. Immediately after the addition, the reaction proceeded to deposit silver chloride as a by-product. The silver chloride was removed by filtration to obtain a colorless and transparent liquid. Water was removed from this solution using an evaporator, and the solution was further vacuum dried to obtain 15.0 g of dehydrated compound 4. It was confirmed that the produced compound 4 was synthesized by H-NMR.

<Synthesis of Compound 5>
Compound 5 was obtained in the same manner as Compound 4 except that 15.7 g of silver salt of 2-acrylamido-2-methyl-1-propanesulfonic acid was used instead of AgPF ₆ .

<Synthesis of Compound 6>
Compound 6 was obtained in the same manner as Compound 4 except that 7.3 g of 1-ethyl-3-methylimidazolium chloride was used instead of methylstyryldimethyldodecylammonium chloride.

[Example 1]
<Synthesis of polymer solid electrolyte and evaluation of ionic conductivity>
In a reaction vessel, 0.5 g of Compound 1 as a normal temperature molten salt not compatible with water, 0.5 g of Compound 4 as a normal temperature molten salt compatible with water, and LiN (SO ₂ CF ₃ ) ₂ as a lithium salt 0.3 g, 0.5 mol% of benzoyl peroxide was added as a polymerization initiator to the total number of moles of charged monomers, and 10 ml of methanol was added thereto to obtain a uniform solution. The obtained solution was cast on a glass plate, heated and polymerized at 80 ° C. for 10 minutes, and further heated for 30 minutes to completely remove the reaction solvent, and a flexible film-like polymer solid electrolyte was obtained. Obtained. The polymer solid electrolyte was produced under a nitrogen atmosphere.
The ionic conductivity of the polymer solid electrolyte obtained above was measured at 25 ° C. by the AC impedance method. The measured frequency range was 50 Hz to 30 MHz, and the voltage was 0.5 V. The measurement results are shown in Table 2.

[Example 2]
A polymer solid electrolyte was prepared in the same manner as in Example 1 except that Compound 5 was used instead of Compound 4 in Example 1, and the ionic conductivity was measured. The measurement results are shown in Table 2.

[Example 3]
A polymer solid electrolyte was prepared in the same manner as in Example 1 except that Compound 6 was used instead of Compound 4 in Example 1, and the ionic conductivity was measured. The measurement results are shown in Table 2.

[Example 4]
A polymer solid electrolyte was prepared in the same manner as in Example 1 except that Compound 2 was used in place of Compound 1 in Example 1, and the ionic conductivity was measured. The measurement results are shown in Table 2.

[Example 5]
A polymer solid electrolyte was prepared in the same manner as in Example 1 except that Compound 2 was used instead of Compound 1 of Example 1 and Compound 5 was used instead of Compound 4, and the ionic conductivity was measured. The measurement results are shown in Table 2.

[Example 6]
A polymer solid electrolyte was prepared in the same manner as in Example 1 except that Compound 2 instead of Compound 1 of Example 1 and Compound 6 instead of Compound 4 were used, and the ionic conductivity was measured. The measurement results are shown in Table 2.

[Example 7]
A polymer solid electrolyte was prepared in the same manner as in Example 1 except that Compound 3 was used instead of Compound 1 in Example 1, and the ionic conductivity was measured. The measurement results are shown in Table 2.

[Example 8]
A polymer solid electrolyte was prepared in the same manner as in Example 1 except that Compound 3 was used instead of Compound 1 of Example 1 and Compound 5 was used instead of Compound 4, and the ionic conductivity was measured. The measurement results are shown in Table 2.

[Example 9]
In a reaction vessel, 0.5 g of Compound 1 as a normal temperature molten salt not compatible with water, 0.5 g of Compound 4 as a normal temperature molten salt compatible with water, and N, N′-methylenebisacrylamide as a crosslinking agent (Shown as BIS in the table) 0.1 g, 0.3 g LiN (SO ₂ CF ₃ ) ₂ as a lithium salt, 0.5 mol% benzoyl peroxide with respect to the total number of moles of monomers charged as a polymerization initiator And 10 ml of methanol was added thereto to obtain a uniform solution. The obtained solution was cast on a glass plate, heated and polymerized at 80 ° C. for 10 minutes, and further heated for 30 minutes to completely remove the reaction solvent, thereby obtaining a flexible film-like polymer solid electrolyte. . The polymer solid electrolyte was produced under a nitrogen atmosphere.
The ionic conductivity of the polymer solid electrolyte obtained above was measured at 25 ° C. by the AC impedance method. The measured frequency range was 50 Hz to 30 MHz, and the voltage was 0.5 V. The measurement results are shown in Table 2.

[Example 10]
In a reaction vessel, 0.5 g of Compound 1 as a normal temperature molten salt not compatible with water, 0.5 g of Compound 4 as a normal temperature molten salt compatible with water, and N, N′-methylenebisacrylamide as a crosslinking agent (In the table, described as BIS) 0.1 g, 0.2 g of LiPF ₆ as a lithium salt, 0.5 mol% of benzoyl peroxide with respect to the total number of moles of charged monomers as a polymerization initiator, Then, ethylene carbonate / propylene carbonate (volume ratio 1/1) (described as EC / PC in the table) was added to obtain a uniform solution. The obtained solution was cast on a glass plate and subjected to heat polymerization at 80 ° C. for 10 minutes to obtain a gel polymer solid electrolyte. The polymer solid electrolyte was produced under a nitrogen atmosphere.
The ionic conductivity of the polymer solid electrolyte obtained above was measured at 25 ° C. by the AC impedance method. The measured frequency range was 50 Hz to 30 MHz, and the voltage was 0.5 V. The measurement results are shown in Table 2.

[Example 11]
<Production of polymer solid electrolyte secondary battery and performance of secondary battery>
A positive electrode mixture was prepared by mixing 85% by weight of LiCoO ₂ as a positive electrode active material, 5% by weight of graphite as a conductive agent, and 10% by weight of poly (vinylidene fluoride) as a binder. The positive electrode mixture was dispersed in N-methyl-2-pyrrolidone to obtain a slurry-like positive electrode mixture. This positive electrode mixture was uniformly applied to both surfaces of a 20 μm thick aluminum foil used as a positive electrode current collector, dried, and then compression molded with a roll press to obtain a positive electrode.
A negative electrode mixture was prepared by mixing 90% by weight of pulverized graphite powder as a negative electrode active material and 10% by weight of poly (vinylidene fluoride) as a binder, and this negative electrode mixture was mixed with N-methyl. A slurry-like negative electrode mixture was prepared by dispersing in 2-pyrrolidone. This negative electrode mixture was uniformly applied to both surfaces of a 15 μm thick copper foil used as a negative electrode current collector, dried, and then compression molded with a roll press to obtain a negative electrode.
The negative electrode and the positive electrode obtained as described above were brought into close contact with each other via a separator made of a polyethylene microporous film having a thickness of 25 μm and wound to obtain an electrode winding body. While this electrode winding body was enclosed in the exterior film which consists of insulating materials, the electrolyte solution before the heating of Example 10 was inject | poured in the exterior film. Then, the outer peripheral edge of the exterior film was sealed, the positive electrode terminal and the negative electrode terminal were sandwiched between the openings of the exterior film, and the electrode winding body was sealed in the exterior film under reduced pressure. This was heated at 80 ° C. for 60 minutes to polymerize the monomer and obtain a polymer solid electrolyte secondary battery. It was found that the obtained secondary battery showed good charge / discharge characteristics.

[Comparative Example 1]
<Synthesis of polymer solid electrolyte and evaluation of ionic conductivity>
The reaction vessel is charged with 0.5 g of compound 1 and 0.5 g of compound 2 as normal temperature molten salts not compatible with water and 0.3 g of LiN (SO ₂ CF ₃ ) ₂ as a lithium salt as a polymerization initiator. 0.5 mol% of benzoyl peroxide was added to the total number of moles of monomers, and 10 ml of methanol was added thereto to obtain a uniform solution. The obtained solution was cast on a glass plate and polymerized by heating at 80 ° C. for 10 minutes, and further, the reaction solvent was completely removed by heating for 30 minutes to obtain a flexible film-like polymer solid electrolyte. . The polymer solid electrolyte was produced under a nitrogen atmosphere.
The ionic conductivity of the polymer solid electrolyte obtained above was measured at 25 ° C. by the AC impedance method. The measured frequency range was 50 Hz to 30 MHz, and the voltage was 0.5 V. The measurement results are shown in Table 2.

[Comparative Example 2]
Comparative Example 1 is the same as Comparative Example 1 except that 0.5 g of Compound 4 and 0.5 g of Compound 5 are used as a normal temperature molten salt having compatibility with water instead of the normal temperature molten salt not compatible with water of Comparative Example 1. A polymer solid electrolyte was prepared by the operation, and the ionic conductivity was measured. The measurement results are shown in Table 2.

  Since the solid polymer electrolyte of the present invention can achieve high ionic conductivity, it can be used for a secondary battery having excellent performance. Moreover, it is thought that this electrolyte is applicable also to general electrochemical elements, such as a capacitor and an electrochromic element.

Claims (5)

  A polymer solid electrolyte comprising a room temperature molten salt having compatibility with water and a room temperature molten salt having no compatibility with water.   The polymer solid electrolyte according to claim 1, comprising a crosslinking agent having two or more radically polymerizable functional groups.   The polymer solid electrolyte according to claim 1 or 2, comprising a nonaqueous solvent.   At least one of the room temperature molten salt having compatibility with water and the room temperature molten salt having no compatibility with water is an acid having an ammonium component having a radical polymerizable functional group and a radical polymerizable functional group. The polymer solid electrolyte according to any one of claims 1 to 3, wherein the polymer solid electrolyte is composed of components.   A secondary battery comprising the polymer solid electrolyte according to claim 1 as a constituent element.