JPH0285388A - Protonic conductive solid electrolyte sheet - Google Patents

Abstract

PURPOSE:To produce a protonic conductive solid electrolyte sheet having superior workability, uniformity and flexibility with superior productivity by kneading a specified percentage of antimonic acid-based solid electrolyte powder with a high molecular elastic body dissolved in a solvent, filling this kneaded material into the openings in an electrically nonconductive meshy body and drying the material. CONSTITUTION:55-95vol.% antimonic acid-based solid electrolyte powder prepd. by mixing Sb2O5 of 100-200 mesh with Sb2O3 of 100-200 mesh in 7:3-10:0 ratio is well kneaded with a soln. prepd. by dissolving a high molecular elastic body such as PVA or polyacrylamide in a solvent such as water, methanol or ethanol. This kneaded material is filled into the openings in an electrically nonconductive meshy body having 35-65% openings, e.g., a woven or nonwoven fabric made of an insulating material such as cellulose, nylon or glass and the filled material is dried to evaporate and remove the solvent. An antimonic acid-based solid electrolyte sheet used as a gas sensor, a humidity sensor, etc., can be produced with superior productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a proton conductive solid electrolyte sheet, and more specifically to an antimonic acid sheet suitable for use in gas sensors, humidity sensors, hydrogen separation membranes, electrochromic displays, etc. The present invention relates to a proton conductive solid electrolyte sheet containing solid electrolyte powder.

[Prior Art] In recent years, electrochromic displays and various sensors using solid electrochemical elements made of antimonic acid-based solid electrolytes have been put into practical use. However, since the solid electrochemical element is fragile to mechanical shock, it is difficult to make it thinner and have a larger area, and there are also problems of poor productivity, uniformity, etc.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the problems of the prior art described above, to achieve a thinner and larger area, to be easy to handle, and to be easy to use when assembling a solid-state electrochemical element. The present invention provides a proton conductive solid electrolyte sheet with excellent processability, productivity, uniformity, and flexibility.

[Means for Solving the Problems] The proton conductive solid electrolyte sheet of the present invention is a mixture in which antimonic acid-based solid electrolyte powder is dispersed in an elastomer polymer at a volume fraction of 55 to 95%. It is characterized by filling the openings of the non-conductive mesh body.

The antimonic acid-based solid electrolyte powder (hereinafter simply referred to as "solid electrolyte powder") used in the present invention includes 5b2o
Examples include a mixture of 5.5b2o5 and 5b2o3,
The ratio is preferably 5b20s/5b20 in weight ratio.
3=4/6~1010, more preferably 7/3~101
It is 0. Outside the above mixing ratio range, it is difficult to obtain sufficient ionic conductivity.

The shape and particle size of these solid electrolyte powders are not particularly limited, but from the viewpoint of ease of mixing with the polymeric elastomer, those that pass through a 100 to 200 mesh (Tyler standard sieve) are preferred. preferable.

Examples of the elastic polymer used in the present invention include 1,
4-Polybutadiene, natural rubber, polyisoprene, SB
R, NBR, EPDMSEPM.

Urethane rubber, polyester rubber, chloroprene rubber, epichlorohydrin rubber, silicone rubber, styrene-butadiene-styrene block copolymer (SBS),
Styrene-isoprene-styrene block copolymer (S
IS), styrene-ethylene-butylene-styrene block copolymer (SEBS), butyl rubber, phosphazene rubber, polyethylene, polypropylene, polyethylene oxide, polypropylene oxide, polystyrene, vinyl chloride, ethylene-ethyl acetate copolymer, 1°2
-Polybutadiene, epoxy resin, phenolic resin, methyl methacrylate, polyvinyl alcohol, polyacrylamide, poly-N,N'-dimethylacrylamide, polymethacrylamide, poly-4-vinylpyridine, poly-toproline, polysarcosine, polyvinyl methyl ether , polyvinyl-2-methoxyethyl ether, polyvinylsulfonic acid amide, polymaleic anhydride, polyN-vinylpyrrolidone, and mixtures thereof.

Among these, polyvinyl alcohol, polyacrylamide, polyvinyl methyl ether, poly-N-
Water-soluble polymers such as vinylpyrrolidone, polymers copolymerized with monomers of water-soluble polymers, or mixtures thereof are preferred, and polymers that swell with or dissolve in water are particularly preferred. Here, swelling due to water refers to volumetric swelling degree (volume of swollen layer at swelling equilibrium/volume of polymer)
means 2 or more, more preferably 5 or more.

The mixture of the solid electrolyte powder and the elastic polymer used in the present invention has a volume fraction of the solid electrolyte powder in the elastic polymer of 55 to 95%, preferably 75 to 92%. If the volume fraction of solid electrolyte powder is less than 55%,
If the ionic conductivity is less than I×10' S am-' and it is not suitable for practical use, and if the volume fraction exceeds 95%,
The solid electrolyte sheet obtained by sheeting becomes brittle, and the solid electrolyte powder easily falls off.

Examples of methods for obtaining the mixture by dispersing the solid electrolyte powder in the elastomer polymer include a method of kneading the elastomer polymer solution in which the elastomer polymer is dissolved in a solvent and the solid electrolyte powder in a ball mill or the like. It will be done. This method generates less heat during kneading, and the solid electrolyte powder is less likely to undergo deterioration or decomposition.

In this case, the solvents used include polar solvents such as water, methanol, ethanol, isopropyl alcohol, acetone, N,N-dimethylformamide, dimethyl sulfoxide, and n-hexane, n-hebutane, n-octane, cyclohexane, Examples include saturated hydrocarbon solvents such as benzene, toluene, xylene, ethyl acetate, and trichlene, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, and ester solvents.

Examples of the non-conductive network used in the present invention include woven or non-woven fabrics made of insulating materials such as cellulose, nylon 6, nylon 66, polypropylene, polyethylene, zeolite, and glass. The aperture ratio of these net-like bodies is suitably in the range of 35 to 65%. The aperture ratio is defined as the ratio of the total aperture area per unit area of the reticular body. If the aperture ratio is less than 35%, the conductivity of the solid electrolyte sheet will be low, and if the aperture ratio exceeds 65%, the effect of maintaining the strength of the solid electrolyte sheet will not be obtained, which is not preferable. In addition, the specific surface area of these networks is 50
A range of 1000rrf/g is suitable. In addition, the basis weight in the case of a nonwoven fabric is suitably in the range of 5 to 50 g1d. The thickness of the net-like body is preferably in the range of 10 to 150 μm in consideration of the strength of the net-like body itself and the thinning of the sheet, and the average area per opening part is 1.6 x 10 -3 to 9 x 10
-2mj, and the width between adjacent openings is 20-120
μm is preferred.

The solid electrolyte sheet of the present invention can be obtained, for example, by filling the openings of a non-conductive network with the solvent-containing mixture (hereinafter referred to as "slurry") obtained as described above, and drying the mixture.

As a method for filling the openings of the net-like body with the slurry, for example, the net-like body is immersed in the slurry, and after the slurry has sufficiently adhered to the net-like body, a blade or roll made of hard rubber, plastic, metal, etc. An example of this method is to fill the openings with slurry, etc., and remove excess slurry. The solid content concentration in the slurry at this time is preferably 20 to 80% by weight.

The slurry filled in the openings of the network is dried, for example, at 20 to 60° C., preferably in an inert gas atmosphere, to form the proton conductive solid electrolyte sheet of the present invention.

The solid electrolyte sheet preferably has a mixture layer of 5 to 25 μm on both or one side of the net-like body in order to improve the adhesion with the electrode layer and conductivity when used in a solid battery.

According to the above method, it is possible to obtain solid electrolyte sheets with extremely high thickness accuracy because the mesh is used as the base material, and because these sheets have excellent flexibility and can be manufactured continuously, large-scale production is possible. A solid electrolyte sheet with a large area can be easily obtained.

The thickness of the solid electrolyte sheet of the present invention obtained in this way is preferably 10 to 250 μm. If the thickness of the sheet is less than 10 μm, it will easily tear and will not maintain its strength. Moreover, when the thickness exceeds 250 μm, the ionic conductivity becomes I
It is likely to be less than 10' S cm-'.

The solid electrolyte sheet of the present invention contains, for example, a modified rosin, a rosin derivative, a terpene resin, a coumaron-indene resin, a phenol-modified coumaron-indene resin, etc. A rosin-based tackifier such as an indene resin, an aromatic tackifier, or a terpene-based tackifier can also be included.

[Examples] The present invention will be explained below using Examples, but the present invention is not limited thereto. In addition, in the examples, parts mean parts by weight.

Example 1 After pulverizing sb2o5/4H20 (manufactured by Kojundo Kagaku Co., Ltd.) using a pestle, the particle size was 20 using a Tyler standard sieve.
A powder of less than 0 mesh was obtained and dried at room temperature and under reduced pressure for 12 hours.

Next, as a polymeric elastomer, 2.7 parts of styrene-butadiene-styrene block copolymer (specific gravity: 0.96, manufactured by Japan Synthetic Rubber Co., Ltd., TR-2000) was dissolved in toluene, and the polymeric elastomer solution was dissolved. Obtained.

The 5b205 obtained above was added to this polymer elastomer solution.
4H20 powder (specific gravity: 3.8) 97. 3 parts were added and kneaded in a ball mill for 2 hours to prepare a slurry with a solid content concentration of 40% by weight.

Next, as a woven fabric, the thickness is 50 μm, the average area per opening is 5.5×10−3−, and the width between adjacent openings is 50 μm.
Using a μm nylon woven fabric, the woven fabric is immersed in the slurry and the mixture is sufficiently adhered to the surface of the woven fabric.
The woven fabric was sandwiched between fluororubber blades and the slurry was filled into the openings of the woven fabric while applying sufficient clamping force. The obtained sheet was thoroughly dried in a nitrogen stream to remove toluene, and the volume fraction of solid electrolyte powder in the polymeric elastomer was 90%.
%, a proton conductive solid electrolyte sheet with a thickness of 70 μm was obtained.

Both sides of the obtained solid electrolyte sheet were pressed with a rubber press at a predetermined pressure using platinum black powder as electrodes to obtain a sheet for measuring electrical properties. Hydrogen is on one side of this sheet, and the mixture ratio of hydrogen and nitrogen is H2/N2 = 1/10 on the other side.
Hydrogen concentration cells with different hydrogen partial pressure ratios were obtained by flowing gases mixed so as to have the following molar ratios, and the electromotive force generated at this time was measured with an electrometer to determine the proton transfer number.

In addition, the sheet for measuring electrical properties obtained as described above was placed in a nitrogen atmosphere (300K) with a relative humidity of 70%.
After leaving it for 12 hours, a DC voltage was applied and the ionic conductivity was measured using an impedance meter. The results are shown in Table 1.

Example 2 Polyvinyl alcohol (specific gravity: 1
．． 26, Gohsenol NH20, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.
) 3.6 parts dissolved in ion-exchanged water, a polymer elastomer solution with a particle diameter of 200
96.4 parts of solid electrolyte powder (specific gravity: 3.8) consisting of 5b2o5.4H20 having a mesh size or less was added and kneaded in a ball mill for 2 hours to prepare a slurry having a solid content concentration of 40% by weight.

Next, the openings of a nylon woven fabric were filled in the same manner as in Example 1 to obtain a proton conductive solid electrolyte sheet having a volume fraction of 90% and a thickness of 75 μm.

The obtained solid electrolyte sheet was tested in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 sb2os・4H20 (manufactured by Kojundo Kagaku Co., Ltd.) and 5b203
(manufactured by Merck & Co.) were weighed so that the weight ratio was 9=1, mixed using a mortar, and ground. After that, a mixed powder with a particle size of 200 mesh or less was prepared using a Tyler standard sieve. The resulting product was dried at room temperature and under reduced pressure for 12 hours.

Next, as a polymer elastic body, polyvinyl methyl ether 3
A polymer elastomer solution was obtained by adding ion-exchanged water to 8 parts of a 0% by weight aqueous solution (Tokyo Kasei Kogyo type). Add the 5b2o5・4H20 obtained above and 5b2 to this polymer elastomer solution.
Solid electrolyte powder (specific gravity = 3.
9) 92 parts were added and kneaded in a ball mill for 2 hours to prepare a slurry with a solid content concentration of 40% by weight.

Next, the openings of a nylon woven fabric were filled in the same manner as in Example 1 to obtain a proton conductive solid electrolyte sheet having a volume fraction of 90% and a thickness of 80 μm.

The obtained solid electrolyte sheet was tested in the same manner as in Example 1, and the results are shown in Table 1.

Table 1 [Effects of the Invention The antimonic acid-based proton conductive solid electrolyte sheet of the present invention has excellent processability, productivity, uniformity, and flexibility, can be made thinner and larger in area, and is conductive. The rate is high;
Because of its large proton transfer number, it is useful as a material for solid electrochemical devices such as gas sensors, humidity sensors, hydrogen separation membranes, and electrochromic displays.

Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] Antimonic acid-based solid electrolyte powder with a volume fraction of 55 to 95%
A proton conductive solid electrolyte sheet, characterized in that the openings of a non-conductive network are filled with a mixture dispersed in an elastomer polymer so as to satisfy the following.