JPH01309205A - Macromolecular gel electrolyte composite - Google Patents

Abstract

PURPOSE:To obtain a solid electrolyte of high ionic conductivity, transparency, mechanical strength and heat resistance by making a matrix polymer, an electrolyte chloride, an organic solvent and a specified 1,3:2,4-dibenzyliden solbitor derivative to be contained in the electrolyte. CONSTITUTION:A matrix polymer consisting of polymerized vinyl monomer, an electrolyte salt compound, an organic solvent and a 1,3:2,4-dibenzyliden solbitor derivative having at least one -COOR radical (R denotes a hydrocarbon radical of 1-20 in carbon number) as a nucleus substitution radical are made to be contained in a solid electrolyte. As for the polymerizable vinyl monomer a methacrylic acid alkylester or the like, as for the electrolyte salt compound a metallic salt of the I and/or the II group in the periodic table or the like, and as for the organic solvent N-methyl formamide or the like can be used respectively. And the solvitor compound can be obtained by the dehydrating condensation reaction of D-solvitor and benzaldehyde under acid catalyzer. Thereby a colorless transparent solid electrolyte of high ionic conductivity, mechanical strength and heat resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polymer gel electrolyte composition having ionic conductivity. More specifically, 1O-38-cII at room temperature
It is a solid electrolyte that can be formed into a thin film with high ionic conductivity and transparency of K-1 or higher, excellent mechanical strength (flexibility) and heat resistance, and is useful for solid electrolyte batteries and electrochromic light displays. The present invention relates to a novel polymer gel electrolyte that can be suitably used as an electrolyte for devices such as (h:cD).

Ion-conductive materials can be used in a wide range of applications, such as secondary batteries, secondary batteries, electrolytic capacitors, SENNA, and ECD components.

[Conventional technology]

Conventionally, ion conductive materials have been used in the form of a solution by dissolving an electrolyte in water or an organic solvent, so there has been a problem of leakage. In order to improve this leakage resistance and develop highly reliable solid electrolyte batteries and ECDs, liquid organic electrolytes have high ionic conductivity, excellent mechanical strength (flexibility), and heat resistance. The development of a good solid electrolyte is desired. Therefore, research on solidifying electrolytes has been actively conducted in recent years.

As inorganic solid electrolytes, various compounds including RITECUM, silver, etc.
No. 930) is known. In addition, as an organic solid electrolyte, we use a complex system of crown ether and alkali metal halide, and a system in which alkaline earth salt is combined with polyethylene oxide as a matrix (Norite State Ionics) (501id 5tate 1onics).
; 3/1.389 (1981)), Composite membrane of polyacrylonitrile, LictO+ and ethylene carbonate (Journal Oppolymer Science) (J,
Polym, Set, ), A2.21.939
(1983)).

However, in both cases, the ionic conductivity at room temperature is 1.
0-8 to 10-58. cm", and its ionic conductivity is extremely low compared to liquid organic electrolytes (hereinafter abbreviated as electrolytes, 10 to 10 S).

On the other hand, it has been reported that a gelling agent (such as a dibenzylidene sorbitol compound) is added to the electrolytic solution to gel the electrolytic solution, thereby improving leakage resistance and obtaining high ionic conductivity. No. 60-163373, etc.). However, conventional gelled products have drawbacks such as being liquefied (at temperatures above 60° C.), being brittle and having poor mechanical strength, and having poor transparency (light transmission J). Particularly in application to display elements, the fact that the solid electrolyte is colorless and transparent for transmission type ECDs and the like is also a problem in terms of mold cost.

[Means for solving problems]

As a result of intensive studies aimed at solving these problems, the present inventors have come to provide the following polymer gel electrolyte composition that can be suitably used as an electrolyte for solid electrolyte batteries, ECD devices, and the like.

That is, the present invention comprises (a) a matrix polymer obtained by polymerizing a polymerizable vinyl monomer, (b) an electrolyte salt compound, (c) an organic solvent, and (d) a 1000R group as a nuclear substituent. (R represents a hydrocarbon group having 1 to 20 carbon atoms.

) and a 1,3:2.4-dibenzylidene sorbitol derivative having at least one sorbitol derivative.

Specifically, the polymerizable vinyl monomer used in the matrix polymer of component (a) of the present invention includes (meth)acrylic acid alkyl ester; unsaturated nitrile such as (meth)acrylonitrile; aromatic olefin such as styrene; Vinyl compounds such as vinyl chloride and vinyl acetate; N-vinyl lactams such as N-vinylpyrrolidone and N-vinylpiperidone; (meth)acrylic acid; ) acrylate; (meth)acrylamide; mono(meth)acrylate of glycerin: polyethylene glycol mono(meth)acrylate; polyallene glycol di(meth)acrylate;
Examples include alkoxypolyethylene glycol mono(meth)acrylate.

The matrix polymer of component (a) can be obtained by polymerizing these polymerizable monomers using a polymerization initiator.

In order to obtain high ionic conductivity, monomers containing alkylene oxide groups such as polyalkylene glycol (meth)acrylate, alkoxypolyalkylene glycol (meth)acrylate, and siloxane-modified polyalkylene glycol (meth)acrylate must be polymerized (and co-polymerized). It is preferable that the polymer is a polymer that can be obtained by polymerization.

As the electrolyte salt compound of component (b) used in the composition of the present invention, metal salts of Group 1 and/or Group H of the periodic table, aluminum salts, quaternary ammonium salts, quaternary phosphonium salts, etc. are used. It will be done. Specifically, Liα0
41 LiBF4, LiPF, .

LiAsFa, LiCFaSOs, KPF6
*KCNS, NaPF6, 'gcm*A
gCl04e (czHs)4NBre (c4Hs
)4NCto4+(c4n9)4PBr and the like are used.

The organic solvent of component (c) used in the composition of the present invention includes amide solvents such as N-methylformamide, NpN'-dimethylformamide, and N-methylpyrrolidinone, carbamate solvents such as N-methyloxazolidinone, N, Urea solvents such as N'-dimethylimidazolidinone, lactone solvents such as γ-butyrolactone and T-valerolactone, carbonate solvents such as ethylene carbonate, propylene carbonate, and butylene carbonate, alcohol solvents such as ethylene glycol and medelcellosolp, sulfolane, Sulfolane solvents such as 3-methylsulfolane, nitrile solvents such as acetonitrile and 3-methoxypropionitrile, phosphate solvents such as trimethylphosphate, ether solvents such as l,2-dimethoxyethane, tetrahydrofuran, 1,3-dioquinrane, and hexane, Examples include hydrocarbon solvents such as benzene and toluene alone or in combination. Moreover, a mixed solvent of the above organic solvent and water can also be used. Among these, it is particularly preferable to use aprotic high dielectric constant organic solvents such as globylene carbonate, ethylene carbonate, γ-butyrolactone, sulfolane, 3-methylsulfolane, and glymes for the purpose of obtaining high ionic conductivity.

In the electrolyte composition of the present invention, the sorbitol compound used as component (d) is obtained by subjecting D-sorbitol and benzaldehydes to a dehydration condensation reaction under an acid catalyst. 2 moles of benzaldehydes are reacted with 1 mole of sorbitol, and in this case, at least 1 mole of benzaldehydes is a p-formylbenzoic acid ester having at least one 1000R substituent as a nuclear substituent. benzaldehydes.

The substitution position of the -COOR group on the benzene nucleus is the ortho position,
Either the meta or para position may be used, but the para position is preferred because it is easily available.

The residue R of the ester group is a hydrocarbon group having 1 to 2 carbon atoms, and may be an alkyl group, an aryl group, or an aralkyl group, but a lower alkyl group is preferable.

(d) Component 1,3: Specific examples of 2,4-dipenzylidene rubitol derivatives include 1,3-(p-methoxycarbonylbenzylidene)-2
,4-pensyritenesorbitol 1.3- (p-methoxycarbonylbenzylidene)-
2,4-(p-methylbenzylidene)sorbitol 1.3-(p-methoxycarbonylbenzylidene)-
2,4-(p-ethylbenzylitine)sorbitol 1.3-(p-methoxycarbonylbenzylidene)-2
,4-(p-methoxybenzylidene)sorbitol 1.3-(p-methoxycarbonylbenzylidene)-2
,4-(p-chlorobenzylidene)sorbitol 1.3-(p-methoxycarbonylbenzylidene)-2
,4-(p-carbamoylbenzylidene)sorbitol l,a-(p-methoxycarbonylbenzylidene)-
2,4-(p-N,N-dimethylcarbamoylbenzylidene) sorbitol 1.3-benzylidene-2,4-(p-methoxycarbonylbenzylidene) sorbitol 1.3: 2,4-bis(p-methoxycarbonylbenzylidene) ) Sorbitol 1.3: 2,4-bis(p-ethoxycarbonylbenzylidene) Sorbitol 1.3: 2.4-1:'su(p-7'roboxycarbonylbenzylidene) Sorbitol 1.3: 2.4- Bis(p-butoxycarbonylbenzylidene) sorbitol 1.3: 2,4-bis(p-hexyloxycarbonylbenzylidene) sorbitol 1.3: 2,4-bis(p-cyclohexyloxycarbonylbenzylidene) sorbitol 1.3: Examples include 2.4-bis(p-phenoxycarbonylbenzylidene) sorbitol.

Among these, those having one nuclear substituent or one each on each benzene nucleus are preferable, and those having no other substituents or those having other substituents, an alkyl or alkoxy substituent Preferably something made by hand.

In the present invention, in order to obtain a solid electrolyte having high ionic conductivity and transparency, and excellent mechanical strength (flexibility) and heat resistance, it is necessary to Proportion: 5% to 50% by weight, preferably 10% by weight, based on the electrolytic solution consisting of component b) and component (c).
It is preferable to prepare the content so as to contain up to 30% by weight.

The proportion of the sorbitol compound (4#) is preferably adjusted to be 0.5% to 10% by weight, preferably 1% to 5% by weight, based on the electrolytic solution.

On the other hand, the ratio of the electrolyte salt compound as the component (b) used in the above electrolyte solution is 5% to the organic solvent as the component (c).
It is preferable to prepare the content so that the content is from 10% to 25% by weight, preferably from 10% to 25% by weight.

The method and material for producing the polymer gel electrolyte composition of the present invention are as follows:
There is a method of obtaining a solid electrolyte composition by polymerizing a polymerizable vinyl monomer in the presence of an electrolyte and a sorbitol compound.

That is, a sorbitol compound is added to an electrolytic solution, a polymerizable vinyl monomer is added and mixed into the homogeneous solution heated and dissolved, and a radical polymerization initiator such as peroxide or an azo compound or light ( A homogeneous solution containing a UV) polymerization initiator is formed into a film-like product by a casting method or a casting method, and heated at 60 to 90°C or exposed to light (UV).
V) Polymerization by irradiation to obtain a thin film of the solid electrolyte composition.

Another manufacturing method is to synthesize a matrix polymer by polymerizing a polymerizable vinyl monomer in advance, and then add and mix an electrolyte and a sorbitol compound into the polymer. Specifically, a polymerizable vinyl monomer is dissolved in a solvent, a normal radical polymerization initiator is added, and a matrix polymer is synthesized by heating and stirring at 40 to 80°C for 4 to 1 shr in an inert atmosphere. However, after forming the matrix polymer into a membrane, a thin film of the polymer gel electrolyte composition can also be produced by immersing the membrane of the matrix polymer in an electrolytic solution in which a sorbitol compound is heated and dissolved.

〔Effect of the invention〕

The polymer gel electrolyte composition of the present invention is colorless and transparent, and
It exhibits high ionic conductivity of L ms -cm-" or more at room temperature, excellent mechanical strength (flexibility), and
A solid electrolyte membrane with good heat resistance that does not liquefy when exposed to temperatures (°C) is obtained, and can be particularly suitably used as an electrolyte for solid electrolyte batteries, ECD devices, electrolytic capacitors, and the like.

〔Example〕

The present invention will be explained below with reference to Examples. These examples are not intended to limit the scope of the invention.

The ionic conductivity was measured using the following method.

After measuring the thickness of the membrane of the polymer gel electrolyte composition of the sample with a micrometer,
A circular gold-plated measuring electrode of ++am was placed in close contact with the whole, and the whole was placed in a nitrogen atmosphere whose temperature was controlled at 25°C. 10”~lO@Hz
AC was applied and the conductivity was measured using the complex impedance method.

In addition, as a heat resistance evaluation method, a predetermined cell is heated to 110°C.
After being placed in the atmosphere for 20 hours, the room temperature (20-25℃)
A heat cycle test was conducted in which the product was installed for 4 hours, and the presence or absence of any abnormality in appearance (discoloration, condition, etc.) was visually observed.

Example 1 (1) 1. Production of 3-(p-methoxycarbonylbenzylidene)-2,4-benzylidene sorbitol 20
D-sorbitol 36.4f (0,
2 mol), water 24. d, benzaldehyde 21.2 f
(0.2 mol) and 2.3f (0.012 mol) of p-)luenesulfonic acid hydrate were added, and under nitrogen atmosphere,
The mixture was stirred at 5°C for 6 hours. After cooling to 20°C, add 100 d of water and hydroxide to the white creamy reaction liquid)
Kumu 0.5? and stirred at room temperature. The white solid obtained by filtering this white slurry was thoroughly washed with water and ether, and dried to obtain 46.49 g of white powder of 2,4-benzylidene sorbitol. (Yield: 185.9%
) Next, in a 2 t flask equipped with a Dean-Stark distillation tube and a strong stirrer, 46.4 f (0.17 mol) of 2,4-benzylidene sorbitol and 27.9 t (0.17 mol) of methyl p-formylbenzoate were added. mole), benzene g
o o f! Lt and 'lJ p-) luenesulfonic acid-
Hydrate 0.32? (1.7 mmol) was added, and the mixture was heated and stirred at a benzene reflux temperature (77° C.) for 6 hours under a nitrogen atmosphere. During the reaction, water distilled into the fractionating tube was extracted as necessary. After the reaction was cooled to the chamber, 300 d of water and 70 to 70 ml of sodium hydroxide were added to the white gel-like reaction solution.
was added and stirred at room temperature.

The white solid obtained by filtering this white slurry was about 70%
Thoroughly wash with warm water at ℃ and ethanol and dry to obtain the desired 1,3-(p-methoxycarbonylbenzylidene).
-2,4-benzylidene sorbitol white powder 65
．． 8F was obtained (Example 1). (Yield 92.0%) (Total yield of D-sorbitol yosho 79.0%) (2) Production of polymer gel electrolyte composition γ-butyrolactone (GBL) 3. oaf (composition weight ratio to polymer gel electrolyte: 60.5 wt%) diperchloric acid + ram (LiCl0a) tD 0.6
0.075P (1.5 wt%) of the above sorbitol compound (Example 1) was added to the electrolytic solution in which f (12 wt%) was dissolved.
were added and mixed and heated at 70°C for 3 hours to completely dissolve. Next, methoxypolyethylene glycol methacrylate (2s in n) (M
1.3 f (26.0 wt%) of PBGM) was added and mixed into the solution, and 4 µm of Perbutyl 0 (PBO1 manufactured by NOF Corporation) was added as a polymerization initiator to form a homogeneous solution.

A portion of the above prepared solution was placed inside a cell made of a polyester film and a glass plate with a space of 2 mm wide, 5 mm long, and 1 mm thick (using a polyester film on the inner surface of the cell, and 10 strips of silicone as a spacer). The polymer gel electrolyte composition was polymerized in a nitrogen atmosphere at 80° C. for 16 hours to obtain a sheet-like polymer gel electrolyte composition. Table 1 shows the properties of the obtained composition.

Example 2 1,3-(p-
methoxycarbonylbenzylidene)-2,4-(p-methylbenzylidene)sorbitol (Example 2) (L2w
A solid electrolyte membrane was obtained in the same manner as in Example 1, except that the solution was completely dissolved by heating at 75° C. for 3 hours. Table 1 shows the properties of the obtained composition.

Example 3 1.3: Using 2,4-bis(p-methoxycarbonylbenzylidene) sorbitol (Example 3), a solid state was prepared in the same manner as in Example 2, except that the heating and thermal polymerization temperatures were changed by 90°C. An electrolyte membrane was obtained. Table 1 shows the properties of the obtained composition.

Comparative Example 1 1.3: 2.4-dipenzylidene rubitol (D
BS) 0.60? Example 1 except that (12 wt%) was used.
A solid electrolyte membrane was manufactured in the same manner as described above. Table 1 shows the properties of the obtained composition. (In order to gel the electrolytic solution, it was necessary to add DBS in an amount of 10 wt% or more.) Comparative row 2 A solid electrolyte membrane was produced in the same manner as in Example 1, except that the sorbitol compound was not used. Table 1 shows the properties of the obtained composition.

Comparative Example 3 DBSo, 6(1' (12 wt%)) was added to an electrolytic solution in which 0.6 f (12 wt%) of lithium perchlorate was dissolved in 3.89 (76 wt%) of γ-butyrolactone,
The mixture was heated at 70° C. for 3 hours to completely dissolve it. Next, a part of the above prepared solution was injected into a predetermined cell in the same manner as in Example 1, cooled to room temperature and left to stand for one day and night to produce a gel electrolyte membrane. Table 1 shows the properties of the obtained composition. The gel was a cloudy, brittle gel with poor mechanical strength, and liquefied upon reheating (at 60° C. or higher).

Example 4 In Example 1, 2-hydroxyethyl methacrylate (HEM
A solid electrolyte membrane was obtained in the same manner as in Example 1, except that the monomer/solvent weight ratio (30/70) was changed to (15/85). Table 2 shows the properties of the obtained composition.

Example 5 A solid electrolyte membrane was prepared in the same manner as in Example 3, except that N-vinylpyrrolidone (NVP, 26 wt%) was used instead of methoxypolyethylene glycol methacrylate (MP EGM, 26 wt%). Obtained. Table 2 shows the properties of the obtained composition.

Example 6 As polymerizable vinyl monomers, 2-hydroxyethyl methacrylate (HEMA, 10.4 wt%) and methoxypolyethylene glycol methacrylate (MP
EGM, 6.9 wt%) type (7) mo/? −
A solid electrolyte membrane was obtained in the same manner as in Example 1, except that lithium trifluoromethanesulfonate (LiCFsSO3) was used as the electrolyte salt compound and the monomer/solvent weight ratio was (20/80).

The properties of the obtained composition are shown in Table 2.

Example 7 In Example 6, γ-butyrolactone (GBL,
A solid electrolyte membrane was obtained in the same manner as in Example 6, except that propylene carbonate (PC, 69.2 wt%) was used as a substitute for 69.2 wt%). Table 2 shows the properties of the obtained composition.

Claims (1)

[Claims] (a) a matrix polymer obtained by polymerizing a polymerizable vinyl monomer, (b) an electrolyte salt compound, (c) an organic solvent, and (d) a -COOR group as a nuclear substituent (R is a carbon number of 1 to 20 A polymer gel electrolyte composition comprising: a 1,3:2,4-dibenzylidene sorbitol derivative having at least one hydrocarbon group.