WO1994006165A1

WO1994006165A1 - Gel electrolyte

Info

Publication number: WO1994006165A1
Application number: PCT/JP1993/001272
Authority: WO
Inventors: Takushi Yamamoto; Kohji Sekai; Morio Nakamura; Yoshio Nishi; Hitoshi Tanaka; Hitoshi Ozawa; Nobuhiro Maeda
Original assignee: Sumitomo Seika Chemicals Co., Ltd.; Sony Corporation
Priority date: 1992-09-08
Filing date: 1993-09-08
Publication date: 1994-03-17
Also published as: JPH06140052A

Abstract

A gel electrolyte prepared by impregnating a composition comprising 100 parts by weight of a cross-linked polyalkylene oxide, prepared by the reaction between a polyalkylene oxide having a weight-average molecular weight of 1,000 to 1,000,000 and an isocyanate, and 0.1-20 parts by weight of an inorganic oxide with a solution of an inorganic electrolyte in a nonaqueous organic solvent. It is excellent in ionic conductivity and mechanical strengths and useful as the material of cells and electrochemical devices.

Description

Description Gel Electrolyte Field of the Invention

The present invention relates to a gel electrolyte. More particularly, it relates to a gel electrolyte suitable as a material for batteries and electrochemical devices.

Background art

In recent years, lithium batteries and electrochemical devices have been actively studied. In particular, lithium batteries have characteristics such as high voltage, large electric capacity, flat discharge characteristics, good low temperature characteristics, and can be used in a wide temperature range, and are used in a wide range of applications. These Lithium batteries usually L i C l 0 ₄ non-aqueous electrolyte an electrolyte dissolved in carbonate such as solutions are used.

Further, Japanese Patent Application Laid-Open No. H11-126667 describes an example in which these non-aqueous electrolyte solutions are solidified and used. That is, a method is described in which a cross-linked polyethylene oxide obtained by reacting a polyethylene oxide with a moso or polyisocyanate compound is used by absorbing the non-aqueous electrolyte solution.

Purpose of the invention

However, ion conduction of a gel electrolyte using a cross-linked polyethylene oxide obtained by reacting a mono- or poly-isocyanate compound with a polyethylene oxide described in JP-A-1-112667. the rate is at 1 O -s S cnr ¹ or less at room temperature, 1 are required as the electrolyte of the battery 0 - is ⁴ S cm- ¹ or more far from. In recent years, the thickness of lithium batteries has become thinner, and a gel electrolyte sandwiched between both electrodes is required to have a thickness of about 100 in to several hundreds. Therefore, both electrodes are easily short-circuited when bent. To prevent this, a gel electrolyte having a high gel strength is required. The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, when a composition obtained by adding an inorganic oxide to cross-linked polyalkylene oxide is used as a gel electrolyte base material, the ionic conductivity is dramatically increased. It has been found that an improved product having high gel strength and good processability can be obtained, and the present invention has been completed. Summary of the Invention

The present invention provides 100 parts by weight of a crosslinked polyalkylene oxide obtained by reacting a polyalkylene oxide having a weight average molecular weight of 1,000 to 1,000,000 with an isocyanate compound and 0.1 part by weight of an inorganic oxide. An object of the present invention is to provide a gel electrolyte obtained by impregnating a composition comprising 20 parts by weight with a non-aqueous electrolyte solution comprising an inorganic electrolyte and a non-aqueous organic solvent.

Detailed description of the invention

Examples of the polyalkylene oxide used in the present invention include polyalkylene oxides having a weight-average molecular weight of 100,000 to 100,000, and examples thereof include polyethylene oxide and polypropylene oxide. And ethylene oxide propylene oxide copolymer and polybutylene oxide. Of these, polyethylene oxide, polypropylene oxide, ethylene oxide and ethylene propylene oxide copolymers having a weight average molecular weight of 2000 to 100,000 are preferably used. If the weight-average molecular weight is less than 1000, the processing temperature becomes high when forming the resulting crosslinked polyalkylene oxide into a film, which makes film formation difficult, which is not preferable. On the other hand, if the weight average molecular weight exceeds 100,000, the cross-linking density of the obtained cross-linked polyalkylene oxide decreases, and the gel strength decreases, which is not preferable.

The above-mentioned isocyanate compound used for crosslinking the polyalkylene oxide is an organic compound containing one or more isocyanate groups (one NCO) in the same molecule, for example, n-propyl isocyanate. Nitrate, n-butyl isocyanate, n-hexyl isocyanate, dodecyl isocyanate, cyclohexyl isocyanate, benzyl isocyanate, phenyl isocyanate, 4,4-diphenylmethane diisocyanate Hexamethylene diisocyanate, 1,8-dimethylbenzoyl 1,2,4-diisocyanate, 2,4-tolylene diisocyanate (TD 1), trimer of TDI, A polyol such as polymethylenepolyphenylisocyanate and trimethylolpropane is added to a polyol having a mole number corresponding to the number of active hydrogens. Urethane iso Xia sulfonate compound obtained by reacting an over bets include a port Li iso Xia sulfonates § duct or the like. Preferably, 4,4-diphenylmethane diisocyanate (MDI) hexamethylene diisocyanate and 2,4-tolylene diisocyanate (TDI :) are used. The amount of the isocyanate compound used depends on the type of the isocyanate compound and the conditions such as the reaction. % Range

If the amount is less than 1% by weight, the crosslinked density of the obtained crosslinked polyalkylene oxide becomes low, and the gel strength becomes low. On the other hand, if the content exceeds 80% by weight, the processing temperature becomes high when the obtained crosslinked polyalkylene oxide is formed into a film, which makes film formation difficult. No. As a method of reacting the polyalkylene oxide with the isocyanate compound, a method of reacting in a solution using an appropriate solvent is generally used.However, a method of reacting in a dispersed state, a method of forming a powder or a solid, and the like. After the two are uniformly mixed, the mixture can be heated to the required temperature for the reaction.

The reaction temperature is usually 50 to 150 ° C.

The reaction may be further promoted by adding a small amount of triethylamine, triethanolamine, dibutyltin laurate, dibutyltin diacetate, triethylenediamine, or the like to the reaction system.

Examples of the inorganic oxide that is a feature of the present invention include silica, titanium oxide, zinc oxide, magnesium oxide, and aluminum oxide. From the viewpoint of uniform dispersibility, the particle size of the inorganic oxide is usually 100 or less, preferably 80 im or less.

As the silica, for example, powdered amorphous silica mainly composed of silicon dioxide, surface-hydrated amorphous silica whose surface is hydrophobized by covering with a methyl group, octylsilyl group or trimethylsilyl group, etc. can be used. .

Examples of the titanium oxide include fine particle titanium oxide containing any one of rutile-type titanium oxide and anatase-type titanium oxide as a main component.

Among these inorganic oxides, silica, titanium oxide, zinc oxide, magnesium oxide and aluminum oxide are preferred.

The inorganic oxide may be added by any method as long as it can be uniformly mixed, such as a method of mixing with stirring during the production of the cross-linked polyalkylene oxide, or a method of mixing the powder with the cross-linked polyalkylene oxide and then melt-mixing. However, the deviation method may be used. The amount of these inorganic oxides is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the crosslinked polyalkylene oxide. If the amount is less than 0.1 part by weight, a sufficient effect of improving the ionic conductivity cannot be obtained, and the gel strength when a gel electrolyte is used cannot be improved.

If the amount exceeds 20 parts by weight, the fluidity of the mixture of the crosslinked polyalkylene oxide and the inorganic oxide at the time of melting is deteriorated, and the molding of the film becomes difficult.

The non-aqueous electrolyte solution in the present invention is a solution obtained by dissolving an electrolyte in a non-aqueous organic solvent.

As the _{_{electrolyte, L'iC10 4, LiBF 4,}} LiAsF 6, LiCF 3 S0 3, LiPF 6, Lil, LiBr, LiSCN, Na I, Li 2 B 10 Cl 10, LiCF 3 C0 2, NaBr, NaSCN, KSCN, MgCl ₂ , Mg (C10 ₄ ) ₂ , (CH ₃ ) ₄ NBF ₄ , (CH ₃ ) ₄ NBr, (C ₂ H ₅ ) ₄ NI, (C ₃ H ₇ ) ₄ N Br, (n-C ₄ H ₉₎ ₄ NI, mention may be made of (n-CsH NI like. preferably, LiCl 0 _{_4,} LiBF ₄ is used.

Non-aqueous organic solvents include propylene carbonate, y-butyrolactone, ethylene carbonate, butylene carbonate, tetrahydrofuran, 2-tetrahydrofuran, 1,3-dioxolan, 4,4-dimethyl-1,3-dioxolan, sulfolane, and 3-methylsulfolane Tert-butyl ether, iso-butyl ether, 1,2-dimethoxetane, 1,2-ethoxymethoxetane, methyldiglyme, methyltetraglyme, ethigrime, ethidiglyme. Preferably, propylene carbonate or arptyrolactone is used.

The gel electrolyte was added to a composition comprising 100 parts by weight of the crosslinked polyalkylene oxide and 0.1 to 20 parts by weight of an inorganic oxide. Beauty nonaqueous inorganic electrolyte concentration made of an organic solvent (about 10 ^-3 to 3 mol / non-aqueous electrolyte solution was 0.001 to 20 g impregnated to crosslinked polyalkylene O wherein de composition lg is prepared.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The formation of the obtained crosslinked polyalkylene oxide composition into a film, the measurement of the ionic conductivity of the film, and the measurement of the gel strength were performed according to the following methods.

<Film>

Prepare crosslinked polyalkylene oxa Lee de and consisting of an inorganic oxide crosslinking Poriaru Kirenokisai de composition 2 g, scissors Teflon sheet, a press under conditions of 120 ° C, 150 kg / cm 2, a film having a thickness of about 100 m did.

The resulting film was in the, by the thickness of this film is about 200 tm urchin, 1M LiC10 ₄ (anhydrous) or 1M LiBF ₄ crush immersed for 24 hours (anhydrous) Z propylene alkylene carbonate solution or Apuchiroraku tons solution, After impregnation, the gel electrolyte film was punched to a diameter of 0.5 cm. This film, about 200 m thick, is sandwiched between platinum electrodes on both sides to form a cell, and an impedance gain phase analyzer (Schlumberger

Instruments, Inc. 1260) measures the AC impedance at a frequency of 30 MHz to 0.05 Hz at room temperature to determine the ionic conductivity of the film.

σ = (l / R, _{i lm} ) (d / s)

(However, R _film is the electrical resistance of the film obtained from the measured AC impedance, s is the area (cm ² ), and d is the thickness (cm))

Asked. Ku gel strength>

The resulting film in the above, this by the thickness of the film is about 200 zm urchin, 1M LiC10 ₄ (anhydrous) or 1M LiBF ₄ (anhydrous) was immersed for 24 hours in propylene alkylene carbonate solution or Apuchiroraku tons solution, impregnation And lcmx cut into 5cm size. The gel strength was evaluated using a precision type leo robot (KA-300P manufactured by Kyowa Seie Co., Ltd.) by the stickiness test by the penetration test method under the following conditions.

Load 2 Οε

1 mm

Load speed SO mZmin

Indenter diameter 2 recitation ø

Load cell 0.1 Kg

Example 11

A 1 liter 4-separable flask equipped with a reflux condenser and stirring blades was charged with 100 g of polyethylene oxide having an average molecular weight of 20000, 550 ml of toluene was added, and then 200 ml of toluene was distilled off to remove water. Distilled. Thereto, 12 g of 4,4, diphenylmethane diisocyanate (MDI) and 0.4 g of triethylamine were added, reacted at 80 ° C. for 3 hours, and then 175 ml of hexane was added. Upon cooling to room temperature, the polymer was precipitated. The slurry was filtered and dried under reduced pressure to obtain 100 g of white crosslinked polyethylene oxide.

Silica (Toxil P, manufactured by Tokuyama Soda Co., Ltd.) was mixed with the powder in an amount of 0.5, 1, 3, or 6 parts by weight with respect to 100 parts by weight of the crosslinked polyethylene oxide, and then the mixture was heated at 120 ° C. Each composition was obtained by melt mixing. Each composition obtained was a film by the method, 1M LiC10 ₄ (anhydrous) Bruno propylene The carbonate solution was impregnated, and the ionic conductivity and the gel strength were measured according to the above-described measurement methods.

Table 1 shows the results.

Example 5

A 1 liter 4-separable flask equipped with a reflux condenser and stirring blades was charged with 100 g of polyethylene oxide having an average molecular weight of 20000, 550 ml of toluene was added, and then 200 ml of toluene was distilled off to remove water. Distilled. To this, 24 g of hexamethylene diisocyanate and 0.8 g of triethylamine were added, and the mixture was reacted at 80 ° C for 3 hours.Then, 175 ml of hexane was added, and the mixture was cooled to room temperature to precipitate a polymer. I let it. The slurry was filtered and dried under reduced pressure to obtain 100 g of white crosslinked polyethylene oxide.

Silica (Toxil P manufactured by Tokuyama Soda Co., Ltd.) was powder-mixed to 3 parts by weight with respect to 100 parts by weight of the crosslinked polyethylene oxide, and then melt-mixed at 120 ° C. to obtain a composition. I got The resulting composition was Fi Lum by the method, 1M LiC10 ₄ (anhydrous) Bruno propylene carbonate solution accordance connexion Ion conductivity on the measurement method was immersed including to measure the gel strength.

Table 1 shows the results. '

Example 6—10

The inorganic oxide type and composition of the added amount was obtained by the same procedure except that instead of those in Table 1, wherein the actual Example 1 into a film by the method, 1M LiC10 ₄ (anhydrous) / propylene carbonate solution And ionic conductivity and gel strength were measured according to the above-mentioned measuring methods.

Table 1 shows the results.

Example 11 A 1-liter 4-separable flask equipped with a reflux condenser and stirring blades was charged with 100 g of polyethylene oxide having an average molecular weight of 8,500, and toluene (5δ0 ml) was added.Then, 200 ml of toluene was distilled off to remove water. Was distilled off. There, 30 g of 4,4-diphenylmethane diisocyanate and 1.0 g of triethylamine were added and reacted at 80 ° C for 3 hours, 175 ml of hexane was added, and the mixture was cooled to room temperature. The polymer was precipitated. The slurry was filtered and dried under reduced pressure to obtain 100 g of a white polymer. .

Silica (Toxil P, manufactured by Tokuyama Soda Co., Ltd.) was powder-mixed to 3 parts by weight with respect to 100 parts by weight of the cross-linked polyethylene oxide, and then melt-mixed at 120 ° C. A composition was obtained. The resulting composition was Fi Lum by the method, 1M LiC10 ₄ (anhydrous) Supporting propylene carbonate solution in the measuring method was immersed containing connexion Ion conductivity was measured gel strength.

Table 1 shows the results.

Example 12

100 g of polyethylene oxide having an average molecular weight of 8500 was placed in a 4-liter separable flask equipped with a reflux condenser and stirring blades, and 550 ml of toluene was added.After that, 200 ml of toluene was distilled off to remove water. Let out. There, 12 g of 2,4-tolylenediocyanate and 0.4 g of triethylamine were added and reacted at 80 ° C. for 3 hours, 175 ml of hexane was added, and the mixture was cooled to room temperature. The polymer was precipitated. The slurry was filtered and dried under reduced pressure to obtain 100 g of a white polymer.

The powder was mixed with 100 parts by weight of this crosslinked polyethylene oxide to 1 part by weight of titanium oxide (manufactured by MT-500B Tika Co., Ltd.), and then melt-mixed at 120 ° C to obtain a composition. Obtained. The resulting composition was by Ri film into the method, 1M LiC10 ₄ (anhydrous) Z propylene carbonate solvent The solution was impregnated, and the ionic conductivity and gel strength were measured according to the above-described measurement methods. Table 1 shows the results.

Example 13

A 1 liter 4-separable flask equipped with a reflux condenser and stirring blades was charged with 100 g of polyethylene oxide having an average molecular weight of 100,000, 550 ml of toluene was added, and then 200 ml of toluene was distilled off to remove water. Distilled. Thereto, 6 g of 4.4-diphenylmethanediisocyanate and 0.2 g of triethylamine were added, and reacted at 80 ° C. for 3 hours, 175 ml of hexane was added, and the mixture was cooled to room temperature, and polymer was cooled. Was precipitated. The slurry was filtered and dried under reduced pressure to obtain 100 g of a white polymer.

Titanium oxide (manufactured by MT-500 B Tika Co., Ltd.) was powder-mixed to 100 parts by weight of this crosslinked polyethylene oxide so as to be 3 parts by weight, and then melt-mixed at 120 ° C to obtain a composition. I got something. The resulting composition was by Ri film into the method, ion conductivity, the gel strength was measured according to the measuring method is impregnated with a 1M LiC10 ₄ (anhydrous) propylene carbonate solvent liquid. Table 1 shows the results.

Example 14

A 1-liter 4-separable flask equipped with a reflux condenser and stirring blades was charged with 100 g of polyethylene oxide having an average molecular weight of 3000, 550 ml of toluene was added, and then 200 ml of toluene was distilled by distillation to remove water. Let out. There, 20 g of 2,4-tolylene diisocyanate and 0.6 g of triethylamine were added, and the mixture was reacted at 80 ° C. for 3 hours, 175 ml of hexane was added, and the mixture was cooled to room temperature. The polymer was precipitated. The slurry was filtered and dried under reduced pressure to obtain 100 g of a white polymer.

100 parts by weight of this cross-linked polyethylene oxide is mixed with silica (Toxi Was mixed with powder so as to be 1 part by weight, and then melt-mixed at 120 ° C. to obtain a composition. The resulting composition was filled beam by said method, ion conductivity, the gel strength was measured in accordance with 1M LiC10 ₄ the measuring method impregnated with (anhydride) Z propylene carbonate solution.

Table 1 shows the results.

Example 15

100 g of an ethylene oxide Z-propylene oxide copolymer having an average molecular weight of 15,000 (copolymerization ratio = 80 to 20) was placed in a 1-liter 4-separable flask equipped with a reflux condenser and stirring blades, and toluene was added. After adding 550 ml, 200 ml of toluene was distilled off by distillation to remove water. Thereto, 6.5 g of 4,4-diphenylmethane diisocyanate and 0.22 g of triethylamine were added, and the mixture was reacted at 80 ° C. for 3 hours. Then, 175 ml of hexane was added, and the mixture was cooled to room temperature. To precipitate the polymer. The slurry was filtered and dried under reduced pressure to obtain 100 g of a white polymer.

Titanium oxide (MT-500B, manufactured by Tika Co., Ltd.) was powder-mixed to 6 parts by weight with respect to 100 parts by weight of the crosslinked ethylene oxide Z propylene oxide copolymer, and then 120 ° C. The composition was obtained by melting and mixing at C. The resulting composition into a film by the method, ion conductivity, the gel strength was measured in accordance with 1 M LiC10 ₄ the measuring method impregnated with (anhydride) propylene carbonate solution.

Table 1 shows the results.

Example 16

A 1-liter 4-separable flask equipped with a reflux condenser and stirring blades was charged with 50 g of polyethylene oxide having an average molecular weight of 11000 and 50 g of polypropylene oxide having an average molecular weight of 4000, and 550 ml of toluene was added. After that, 200 ml of toluene was distilled off by distillation to remove water. Thereto, 18 g of 4,4-diphenylmethane diisocyanate and 0.6 g of triethylamine were added and reacted at 80 ° C for 3 hours. Then, 175 ml of hexane was added, and the mixture was cooled to room temperature. Upon cooling, the polymer precipitated. The slurry was filtered and dried under reduced pressure to obtain 10 Og of a white polymer.

Powder was mixed with 3 parts by weight of silica (FINE SEAL T-32 manufactured by Tokuyama Soda Co., Ltd.) to 100 parts by weight of the crosslinked polyethylene oxide / polypropylene oxide mixture mixture, and then heated to 120 ° C. To obtain a composition. Resulting into a film by a composition the method, 1M LiCl 0 ₄ (anhydrous) propylene carbonate solution Te従Tsu the measuring method impregnated with ion conductivity was measured gel strength.

Table 1 shows the results.

Example 1

In a 1-liter 4-separable flask equipped with a reflux condenser and stirring blades, add 10 Og of polyethylene oxide having an average molecular weight of 20000 and silica (Toxil P, manufactured by Tokuyama Soda Co., Ltd.) After adding 550 ml of toluene, 200 ml of toluene was distilled off by distillation to remove water. Thereto, 12 g of 4,4-diphenylmethanediisocyanate and 0.4 g of triethylamine were added, and the mixture was reacted at 80 ° C. for 3 hours. Then, 175 ml of hexane was added, and the mixture was cooled to room temperature. The polymer was precipitated. The slurry was filtered and dried under reduced pressure to obtain 10 Og of a polymer.

This crosslinked polyethylene oxide was formed into a film by the above method, and 1M

LiC10 ₄ (anhydrous) / propylene carbonate solution ionic conductivity according to the measuring method impregnated was measured gel strength.

Table 1 shows the results. Example 18

100 g of polyethylene oxide with an average molecular weight of 20000 and fine silica particles (Aerozil R-805 manufactured by Nippon Aerozinole Co., Ltd.) in a 1-liter 4-separable flask equipped with a reflux condenser and stirring blades 3. Og After adding 550 ml of toluene, 200 ml of toluene was distilled off by distillation to remove water. To this, 3,4 diphenylmethane diisocyanate (3 Og) and triethylamine (1 Og) were added, reacted at 80 ° C for 3 hours, hexane (175 ml) was added, and the mixture was cooled to room temperature. Then, the polymer was precipitated. The slurry was filtered and dried under reduced pressure to obtain 10 Og of a polymer.

This crosslinked polyethylene oxide was formed into a film by the above method, and the ionic conductivity and gel strength were measured according to the above measurement method.

Table 1 shows the results.

Example 11

Finolem thickness (m)

Implementation Inorganic oxide addition amount 1 LiC10 ₄ Ionic conductivity Gel strength Example (parts) Before absorption (anhydride) / pro m S cm " ¹ dyne * sec

Pyrene force-bonate (room temperature) / cm ² after solution absorption

1 Silica (Tokuyama Soda Co., Ltd. 0.5 90 200 2.9 5700 Toxil P)

2 1.0 90 190 4.1 6200

3 3.0 100 210 6.3 7200

4 6.0 1 in 6.7 7900

5 3.0 100 210 6.0 7000

6 Silica (Tokuyama Soda Co., Ltd. 5.0 no y 220 3.7 7700 F-in seal T-32)

7 Titanium oxide (Taika Corporation 1.0 inn 210 3.2 6400 MT-500B)

8 Zinc oxide (塄 Chemical 1.0 90 200 3.4 5200 Industrial FINEX-25)

9 Magnesium oxide 1.0 100 200 2.3 5000 (Wako Pure Chemical Industries)

10 Oxidized Luminium 3.0 100 190 2.5 6200 (Wako Pure Chemical Industries)

11 Silica (Tokuyama Soda Co., Ltd. 3.0 110 210 4.5 7100 Toxil P)

12 Titanium oxide (Tika Corporation 1.0 100 190 2.9 6700 MT-500B)

13 Titanium oxide (Tika Corporation 3.0 110 200 3.6 7200 HT-500B)

14 Silica (Tokuyama Soda Co., Ltd. 1.0 100 210 2.8 6200 F-in seal T-32)

15 Titanium oxide (Tika Corporation 6.0 110 220 3.8 9200 MT-500B)

16 Silica (Tokuyama Soda Co., Ltd. 3.0 120 220 3.0 9700 F 7 Seal T-32)

17 Silica (Tokuyama Soda Co., Ltd. 1.0 90 200 2.9 6200 Token P)

18 Silica (Nippon Ryo ID Jill 3.0 100 210 11.4 11000 E-805) Example 19

100 parts by weight of the cross-linked polyethylene oxide obtained in Example 1 was powder-mixed with 3 parts by weight of Siri force (Toksil P manufactured by Tokuyama Soda Co., Ltd.), and then melt-mixed at 120 ° C. Thus, each composition was obtained. The resulting composition into a film by the method shown 1M LiBF ₄ ion conductivity according to the measuring method impregnated with (anhydrous) A one Puchiroraku tons solution, _c result of measuring the gel strength in Table 2.

Example 20

A composition was obtained in the same manner as in Example 19 except that the inorganic oxide was titanium oxide (manufactured by MT-500 B Tika Co., Ltd.) and the amount added was 1 part by weight, and the composition was formed into a film by the above method. Ionic conductivity and gel strength were measured according to the measurement method.

Table 2 shows the results.

Table 2 Example 19--20

Film thickness (m)

Implementation Inorganic oxide addition amount 1 LiBF ₄ Ionic conductivity Gel strength Example (parts) Before absorption (anhydride) / ffiScm " ¹ dyne * sec arbuty D-lactone (room temperature) / cm 'After solution absorption

19 Silica (Tokuyama Soda Co., Ltd. 3.0 90 200 1.8 7200

(Toksil P)

20 Titanium oxide (Tika Corporation 1.0 100 190 2.0 6700

ΜΤ-δΟΟΒ) Comparative Example 1

A film was formed in the same manner as in Example 1 except that the inorganic oxide was not added to the crosslinked polyethylene oxide obtained in Example 1, and the ion conductivity and the gel strength were measured according to the above-described measurement methods.

Table ³ shows the results.

Comparative Example 2

To 100 parts by weight of the crosslinked polyethylene oxide obtained in Example 1, 0.05 parts by weight of silicic acid (Tokusil P manufactured by Tokuyama Soda Co., Ltd.) was added, and after mixing with powder, 1 part by weight was added. The composition was obtained by melt mixing at 20 ° C. The obtained composition was formed into a film by the above method, and the ion conductivity and the gel strength were measured according to the measurement method.

Table 3 shows the results.

Table 3 Comparative Example 1 1 3

Comparative Example 3

100 parts by weight of the crosslinked polyethylene oxide obtained in Example 1 was added with 25 parts by weight of silicic acid (Toksil P, manufactured by Tokuyama Soda Co., Ltd.), and the powder was mixed. The composition was obtained by melt mixing at 20 ° C. The resulting composition, An attempt was made to form a film by the above method, but the thickness was 2 mm and a thin film could not be formed.

The gel electrolyte obtained by the present invention has a high ion conductivity and a high mechanical strength, so that it can be used with a reduced thickness when used. Therefore, when used as an electrolyte, thinner batteries and electrochemical materials are used.In particular, when used as a gel electrolyte for lithium batteries, high voltage, large electric capacity, and flatness are achieved despite their small size. A thin lithium battery with discharge characteristics and good low-temperature characteristics that can be used in a wide temperature range will be possible. Therefore, the gel electrolyte obtained by the present invention is excellent as a material for batteries and other electrochemical devices, and is particularly suitably used as a gel electrolyte for lithium batteries.

Claims

The scope of the claims

1. 100 parts by weight of a cross-linked polyalkylene oxide obtained by reacting a polyalkylene oxide having a weight-average molecular weight of 1,000 to 10,000 with an isocyanate compound and inorganic oxide 0.1 to A gel electrolyte obtained by impregnating a composition consisting of 20 parts by weight with a non-aqueous electrolyte solution containing an inorganic electrolyte and a non-aqueous organic solvent.

2. The gel electrolyte according to claim 1, wherein the polyalkylene oxide is at least one selected from the group consisting of polyethylene oxide, polypropylene oxide, a mixture thereof, and a copolymer thereof.

3. The isocyanate compound is at least one selected from the group consisting of 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, and 2,4-tolylene diisocyanate. The gel electrolyte as described.

4. The gel electrolyte according to claim 1, wherein the inorganic oxide is at least one selected from the group consisting of silica, titanium oxide, zinc oxide, magnesium oxide, and aluminum oxide.

5. The gel electrolyte according to claim 1, wherein the inorganic electrolyte is lithium perchlorate or lithium boron tetrafluoride.

6. The gel electrolyte according to claim 1, wherein the non-aqueous organic solvent is propylene carbonate or ester lactone.