JPH01192742A - Proton conductive amorphous material and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title structurally stable material, having high proton conductivity and excellent in processability, by mixing a solution containing a specific metallic compound with a solution containing a hydrous heteropoly- acid and hydrolyzing or condensing the metallic compound. CONSTITUTION:A solution or dispersion containing a metallic compound having a hydrolyzable and/or condensable group and/or derivative thereof is homogeneously mixed with a solution containing a hydrous heteropoly-acid and/or salt thereof. The metallic compound or derivative is then hydrolyzed and/or condensed, Thereby, a proton conductive amorphous material containing the hydrous heteropoly-acid and/or salt thereof highly dispersed in an amorphous metallic oxide is obtained. The hydrous heteropoly-acid means a heteropoly-acid containing water, which may be in the form of either water of crystallization or free water.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a proton-conducting amorphous material used as a solid electrolyte in electrochemical devices such as sensors, solid secondary batteries, fuel cells, and electrochromic devices. .

[Prior Art] Conventionally, among the solid electrolytes used in electrochemical devices, those having high proton conductivity include phosphotungstic acid (IsPWtgO4oshanHg0), phosphomolybdenum r14 (H3PMoi20to' nHgo),
Tungstic silicoic acid (HaS i WttOao-n
Heteropolyacids such as Hg0) are known. When using the heteropolyacid as the above-mentioned solid electrolyte, the powder of the heteropolyacid has been compression molded under high pressure to form a solid electrolyte membrane, but since the heteropolyacid is a hydrous crystal, processing is difficult. It had disadvantages such as poor properties, difficulty in forming a thin film, weak strength, and brittleness.

Furthermore, since the heteropolyacid absorbs or releases water molecules depending on the surrounding atmosphere, its crystal structure changes over time and it tends to form large crystals.

Therefore, molded bodies of the heteropolyacid used in electrochemical devices and the like are susceptible to distortion, causing problems such as cracking and poor adhesion with electrodes.

In order to prevent and suppress this heteropoly acid structural change and crystallization over time, a proton conductor in which a metal oxide is impregnated with the heteropoly acid (Japanese Patent Application Laid-Open No. 60-220503) has been proposed. Since this method uses oxide powder, there were also problems in terms of pressurability, such as thinning the film.

On the other hand, in order to make a solid electrolyte suitable for thinning, there is a proposal (Japanese Patent Laid-Open No. 172084/1984) to mix the heteropolyacid with an organic polymer to improve flexibility and processability. In addition to insufficient conductivity, there were also problems with heat resistance, such as the solid electrolyte membrane becoming colored and proton conductivity decreasing when exposed to high temperatures.

[Problems to be Solved by the Invention] The present invention provides a proton conductive amorphous material that has high proton conductivity, is structurally stable, and has excellent heat resistance, durability, and processability such as thinning. It provides a manufacturing method.

[Means and effects for solving the problem] The present invention provides hydrous heteropolyacids and/or hydrous heteropolyacids,
This invention relates to a proton-conducting amorphous material highly dispersed in an amorphous gold R oxide. Furthermore, a solution or dispersion containing a metal compound and/or a derivative thereof that can be hydrolyzed and/or condensed to form an amorphous metal oxide is mixed with a solution containing a hydrous heteropolyacid and/or a hydrous heteropolyacid salt. The present invention then relates to a method for producing a proton-conducting amorphous material, characterized in that the metal compound and/or its derivatives are integrated into a composite material by hydrolysis and/or condensation.

The hydrous heteropolyacid used in the present invention means a heteropolyacid containing water, and the water may be in the form of crystal water or free water of the heteropolyacid.

Heteropolyacid is a general term for acids produced by condensation of two or more types of inorganic oxyacids. Phosphotungstic acid, a typical heteropolyacid, is synthesized by reacting phosphate ions and tungstate ions under acidic conditions. The petro atom, which is the center of the heteropolyacid anion, has ■
It is known that elements such as Mo1 Wl Nb- and V are included in the poly atom, which is an atom in which the -■ group element is incorporated and coordinates to the Peter atom via oxygen. Heteropolyacids with various structures have been synthesized depending on the types of polyatoms and peteroatoms and their condensation ratios, and have been reported, for example, by Sasaki et al., Chemistry Region, Vol. 29, p. 853 (1975). The item is representative. In addition, there are also species called mixed coordination species that contain two or more types of polyatoms in the same molecule. These heteropolyacids are preferably used in the present invention. In addition, some of the protons of the heteropolyacid can be replaced with alkali metals, alkaline earth metals, Hg,
Ag.

Heteropolyacid salts can be synthesized by replacing TI, Cu, etc. with transition gold, ammonium, organic amino groups, etc., and these salts also satisfy the requirements of the present invention. A heteropolyacid can have a large amount of water of crystallization, and in a hydrous heteropolyacid, part or all of the water is coordinated as water of crystallization of the heteropolyacid. The water of crystallization is in the form of protonated aqua cations and is involved in the structure of crystals having a face-centered cubic lattice arrangement, and proton conduction is mainly carried out through this water of crystallization.

On the other hand, the amorphous metal oxide of the present invention refers to a structure in which most of the M-0-M (M is a metal element, 0 is oxygen) bonds form a three-dimensional network. It refers to something that does not show clear peaks based on its crystal structure in terms of line diffraction. Various groups derived from the raw metal compound and/or its derivative may remain on its surface or inside. As the elements constituting the amorphous metal oxide, it is preferable to use Group II and Group IV&V of the Periodic Table of Elements, and B and A11Si are particularly likely to form an amorphous network.

Preference is given to using Ge, Sn, PS Ti and Zr. If necessary, some elements other than the above, such as Fe, BeSM gs N 1sZn, may be added for the purpose of further improving proton conductivity and processability during manufacturing.
% Co, Ca, Sr, Ba1 Li,
Na1K.

By adding Cs etc., the crosslinking density of the metal oxide network,
It is also possible to control physical properties such as specific gravity, dielectric constant, and heat resistance.

The present invention enables protonation by highly dispersing a hydrous heteropolyacid and/or a hydrous heteropolyacid salt in an amorphous metal oxide to the extent that X-ray diffraction does not show clear peaks based on the crystal structure. The present invention provides a proton conductive amorphous material that has high conductivity, is structurally stable, and has excellent heat resistance, durability, and processability.

In the present invention, the proton-conducting amorphous material is obtained by dissolving or dispersing a metal compound and/or a derivative thereof having a hydrolyzable and/or condensable group in a solvent;
A solution containing a hydrated heteropolyacid and/or a hydrated heteropolyacid salt is mixed uniformly, water and an acid or alkali as a catalyst are added if necessary, and the metal compound and/or its derivative is hydrolyzed and/or heated. Or produced by condensation. According to the method of the present invention, the hydrous heteropolyacid or its salt is first dissolved or molecularly dispersed in a solvent, so that it is highly dispersed in an amorphous network through hydrolysis and/or condensation reactions. It is fixed in a fixed state. This means that in the infrared absorption spectrum of the proton-conducting amorphous material produced, a vibrational spectrum characteristic of a hydrated heteropolyacid or its salt is observed, but in X-ray diffraction, a diffraction peak characteristic of a hydrated heteropolyacid or its salt is observed. This was confirmed by the fact that it was not observed. Further, according to the method of the present invention, since a solid phase can be generated from a solution, it is possible to suitably form a thin film by dipping, casting, or the like.

The metal compound having a hydrolyzable and/or condensable group is one that can form a three-dimensional network, and includes metal halides, metal nitrates, metal sulfates, metal ammonium salts, organometallic compounds, alkoxy It means a metal compound, etc., and can be used alone or in combination. Preferred metal compounds include general formulas (R'), M (R2) , (X), and (Y).

(However, M is a metal element; &R2 is at least one group selected from the group consisting of halogen, NOl, hydroxyl group, acyloxy group, and alkoxy group, rrh p and q are 0 or a positive number, and n is a positive number and satisfies the valence of 2p+m+n-q=metal element M.Also, m R1s may be different<, n R2, p
The same goes for 9 Y. ). If the above R1+ is a halogen, NO3, etc., the produced proton conductive material may easily corrode the electrodes of electrochemical devices, etc. Therefore, depending on the field of use, avoid using compounds with these groups. In some cases, it may be preferable to do so. Therefore, as Rz, hydroxyl, acyloxy, and alkoxy groups are more preferably used. Also, the above X also has SO4 for the same reason.
In some cases it may be preferable to avoid the use of groups. In addition, n
A metal compound with 3 or more can be used alone, but n=
Metal compounds represented by 1 or 2 can be used together with raw materials having three or more hydrolyzable groups.

In the above R1, the number of substituents m is 0 or a positive number, but in order to improve the flexibility of the generated metal oxide and the adhesion with the electrode, a metal compound where m is not O may be appropriately used. is valid.

The above general set (R1) = M (R2), (X), (Y)
.

Specific examples of metal compounds represented by are boric acid, ammonium borate, boron tribromide, boron trichloride, methyl borate dichloride, trimethyl borate, triethyl borate,
Triisopropyl borate, tributyl borate, methyl boric acid, dimethyl methyl borate, aluminum hydroxide, aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum ammonium sulfate, aluminum trimethoxide, aluminum triethoxide, aluminum triisopropoxide, aluminum tributoxide,
Dimethylaluminum methoxide, isopropylaluminum dichloride, ethyl ethoxyaluminum chloride, silicon tetrachloride, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, dimethylethoxysilane, phenyltrihydroxysilane, trimethylhydroxysilane, dimethyldihydroxysilane, methyltrichloride Acetoxysilane, dimethyldiacetoxysilane, trimethylacetoxysilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, trimethoxyvinylsilane, triethoxyvinylsilane,
3-glycidoxyprobyl ← Rimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(2-aminoethylaminoprobyl)trimethoxysilane, phenyltrimethoxysilane, phenyltrimethoxysilane Ethoxysilane, dimethoxydimethylsilane, dimethoxymethylsilane, jetoxymethylsilane, jetoxy-3-glycidoxypropylmethylsilane, 3-chloropropyldimethoxymethylsilane, dimethoxydiphenylsilane, dimethoxymethylphenylsilane, trimethylmethoxysilane, trimethyl Ethoxysilane, dimethyljethoxysilane, dimethoxyjethoxysilane, germanium tetrachloride, methylgermanium trichloride, dimethy.

germanium dichloride, trimethylgermanium chloride, methylgermanium triacetate, dimethylgermanium diacetate, trimethylgermanium acetate, germanium tetramethoxide, germanium tetraethoxide, methylgermanium triethoxide, dimethylaluminum methoxide, trimethylgermanium methoxide, primary chloride Tin, stannic chloride, methyltin trichloride, dimethyltin dichloride, trimethyltin chloride, dibutyltin diacetate, tributyltin hydride, trimethyltin formate, trimethyltin acetate, triethyltin hydroxide, dimethyltin dimethoxide, trimethyltin methoxide, Dimethyltin jetoxide, dibutyltin dibutoxide, phosphorous acid, phosphoric acid, phosphorus trichloride, phosphorus oxychloride, phosphorus pentachloride, ammonium phosphate, triammonium phosphate, triammonium phosphate, methylphosphite dichloride, phenyl phosphorus Acid dichloride, dimethyl phosphite chloride, methyl phosphorous dichloride, methyl phosphorous acid, methyl phosphorous acid, trimethyl phosphite, triethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite, methyl phosphorous Diethyl acid, diethyl phenyl phosphite, ethyl dimethyl phosphite, ethyl diphenyl phosphite, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dimethyl methyl phosphate, diethyl ethyl phosphate, ethyl dimethyl phosphate, diethyl phosphate Methyl, titanium tetrachloride, titanyl sulfate, methyltrichlortitanium, dimethyldichlorotitanium, tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, tetra(2-ethylhexyloxy)titanium, jetoxydibutoxytitanium , isopropoxy titanium triisostearate, isopropoxy titanium trioctate, diisopropoxy diacrylate, tributoxy titanium stearate, zirconium tetrachloride, zirconium oxychloride, zirconium acetate, zirconium lactate, zirconium tetramethoxide, zirconium tetraethoxy Examples include zirconium tetrabutoxide, zirconium tetraisopropoxide, and zirconium tetrabutoxide.

Further, other preferable compounds include derivatives of the above metal compounds. These derivatives include, for example, R''
Some of the groups are dicarboxylic acid groups, oxycarbon It! in
, β-diketone group, β-ketoester group, β-diester group, a metal compound substituted with a group capable of forming a chelate compound such as an alkanolamine group, or the metal compound and/or the chelate-substituted metal compound partially hydrated. A reactive oligomer obtained by decomposition and/or condensation, a polymer 8, and a particle size of 0. Examples include metal oxide fine particles of 1 μm or less.

Examples of the above chelate-substituted metal compounds include diisopropoxytitanium diacetylacetonate, oxytitanium diacetylacetonate, dibutoxytitanium bistriethanolaminate, dihydroxytitanium dilactate, zirconium acetylacetonate, acetylacetone zirconium butoxide, and ethyl acetoacetate. Examples include zirconium butoxide, triethanolamine zirconium butoxide, aluminum acetylacetonate, and the like.

Reactive oligomers, polymers and particle sizes of 0 and 1 as described above
The metal oxide fine particles having a size of less than μ may be obtained by partial hydrolysis of the metal compound and/or the chelate-substituted compound, but it is convenient to use commercially available reactive oligomers and polymers, such as reactive dimethylpolysiloxane. In addition, water-dispersible sols or organosols of silica, alumina, titania, etc. can also be suitably used.

[Effects of the present invention]

The material of the present invention has the hydrated heteropolyacid and/or hydrated heteropolyacid salt highly dispersed in the gold rrArm compound, so it has high proton conductivity, excellent heat resistance, and durability. It is suitable for forming an H film by a method, and is suitable as a solid electrolyte for electrochemical devices.

[Examples] The present invention will be explained in detail by way of Examples below, but the scope of the present invention is not limited by these Examples.

Plan J - Hydrous wontungstic acid (HzP W two 4 (1
・Dissolve 7.88 g of 29820 (manufactured by Japan Inorganic Chemical Industry 99, hereinafter abbreviated as PW) in 10 g of water, and then stir it into a mixed solution of 10 g of tetramethoxysilane (hereinafter abbreviated as MS) and methanol Log. I put it down. After stirring for about 10 minutes while heating, a portion of the solution was taken and poured into a petri dish. After air drying at room temperature for one week, a transparent amorphous glassy thin film with a thickness of 1.51 mm was obtained. A portion of this thin film was taken, sandwiched between platinum electrodes, and the proton conductivity was measured by applying a Cole-Cole plot using an AC impedance meter.2. It was OX 10-"Sew-'.

Furthermore, when the above-mentioned glass wipe RM'A was subjected to X-ray diffraction analysis, no diffraction peak specific to PW was observed, and only a broad peak similar to silica gel was observed. However, in the infrared absorption spectrum, a vibrational spectrum (1080,985,887,807 am-') peculiar to PW was observed. From these results, it was considered that PW existed in a highly dispersed state in the silica amorphous network.

Uratanegetsu 2 Dissolve 3.3g of PW in 5g of water, then mix 4.2g of MS and 87.5g of isopropyl alcohol i1! The mixture was added dropwise to the F solution while stirring. After stirring at 50° C. for 24 hours, a proton conductive thin film was formed on a glass slide whose surface had been thoroughly cleaned by dipping to obtain a transparent film.

When the film thickness was measured after drying at 80°C for 1 hour, the average thickness was 10
There were 00 people. A comb-shaped gold electrode was vacuum-deposited on this rIj film, and after leaving it for 24 hours at 30°C and 85% RH (relative humidity), the proton conductivity was measured in the same manner as in Example 1. Met. Furthermore, the proton conductivity of this thin film was adjusted to 10.3 at a temperature of 85% RH.
The temperature was changed to 0.50.80°C and measured. 3 The results are shown in Table-1.

Table 1 Also, after treating this thin film at 100°C for 100 hours,
Proton conductivity was measured using the same method as in Example 1.2. It was 2X 10-3Sc+s-'.

When the logarithm of the conductivity is plotted against the reciprocal of the absolute temperature, it becomes a nearly straight line, and the activation energy was calculated to be about 21 KJ/mol from the slope.

This is equivalent to hydrogen bond energy, and the conductivity of this thin film is thought to be due to the movement of protons via water molecules dispersed in the amorphous silica. Furthermore, 10
X-ray diffraction analysis of the #film after the 0°C heat resistance test revealed that it maintained almost the same amorphous state as before the test. This suggests that the stability of this structure suppresses the deterioration of conductivity over time.

Example 2 except that 1 width of back dust = 1 hydrated heteropolymer acid shown in Table 2 was used instead of 3.3 g of PW, and the metal compound and/or its derivative shown in Table 2 was used instead of 4.2 g of MS. The proton conductivity was measured in the same manner. The results are shown in Table 2 (abbreviations in the table are as follows). Also,
In all cases, no diffraction peak specific to PW was observed in X-ray diffraction analysis.

Abbreviations in the table> ES---φ・Tetraethoxysilane MTMS...Methyltrimethoxysilane GTMS...
・7-Gelicidoxybrobyltrimethoxysilane TMB・・Trimethyl borate TBA・・Aluminum tributoxide TEG-Φ
Ichiban germanium triethoxide TEP...Triethyl phosphate DPAT...Titanium diisopropoxy acetylacetonate T B Z...Zirconium tetrabutoxide BT
A...Dibutyltin diacetate KFIOI...manufactured by Shin-Etsu Chemical Co., Ltd., epoxy modified polydimethylsiloxane 5TXN...manufactured by Nissan Chemical Industries, Ltd., Silica Sol N521
0...6 Hara Sangyo (manufactured by 111, Titania Sol TBT-ψ・
・Tetrabutoxytitanium ratio 1 "Example".

PW thick 1. It was pressure molded to a length of 5 m. The proton conductivity of this molded body was measured to be 8×10-”S.
cva-''. This molded body was subjected to a heat resistance test at 100° C. in the same manner as in Example 4, but the molded body was cracked after 100 hours and had a problem in durability.

Heat and dissolve 1.97g of POVAL (PVA-203, manufactured by Kuraray ■) in 15g of water, and add 3.97g of PW to this and 5g of water.
A solution of the solution was added under stirring. After heating and stirring for 1 hour, it became a highly viscous and transparent liquid. This liquid was sandwiched between Nesagalas with platinum lead wires, and the proton conductivity was measured after leaving it at 30°C and 85% RH for 24 hours. 1
×10'''''Saw''''l, and the conductivity was low. Furthermore, when the temperature was raised to 80° C. for a heat resistance test, the material gradually devitrified, turned black after 1 hour, and the proton conductivity decreased.

Patent applicant Nippon Shokubai Chemical Co., Ltd. Procedural amendment (
(Voluntary) April 11, 1986

Claims (1)

[Scope of Claims] 1. A proton-conducting amorphous material in which a hydrous heteropolyacid and/or a hydrous heteropolyacid salt are highly dispersed in an amorphous metal oxide. 2. The proton conductive amorphous material according to claim 1, wherein the metal oxide is at least one metal oxide selected from the group consisting of elements of Group III, Group IV, and Group V of the Periodic Table of Elements. 3 Metal oxide is B, Al, Si, Ge, Sn, P, T
The proton conductive amorphous material according to claim 1, which is at least one metal oxide selected from the group consisting of i and Zr. 4. After uniformly mixing a solution or dispersion containing a metal compound and/or its derivative having a hydrolyzable and/or condensable group and a solution containing a hydrous heteropolyacid and/or a hydrous heteropolyacid salt, the metal 2. The method for producing a proton-conducting amorphous material according to claim 1, which comprises hydrolyzing and/or condensing a compound or a derivative thereof. 5 The metal compound has the general formula (R^1)_mM(R^2)_n(X)_p(Y)_q
(However, M is a metal element; at least one group selected from the group of group residues, R^2 is halogen, NO
_3, at least one group selected from the group consisting of hydroxyl group, acyloxy group, and alkoxy group, m, p and q are 0
or a positive number, and n is a positive number, 2p+m+n
-q=the valence of the metal element M is satisfied. Further, the m R^1's may be different, and the same applies to the n R^2, the p X's, and the q Y's. ) The method for producing a proton conductive amorphous material according to claim 4, characterized in that: 6. The proton conductive amorphous material according to claim 5, wherein the substituent R^2 of the metal compound consists of at least one group selected from the group consisting of a hydroxyl group, an acyloxy group, and an alkoxy group. Production method. 7. The method for producing a proton conductive amorphous material according to claim 5, wherein the substituent X of the metal compound is oxygen. 8. The metal element M of the metal compound according to claim 5, wherein the metal element M is at least one metal element selected from the group consisting of elements of group III, group IV, and group V of the periodic table of elements. A method for producing a proton-conducting amorphous material. 9 The metal element M of the metal compound is B, Al, Si, Ge
6. The method for producing a proton conductive amorphous material according to claim 5, wherein the metal element is at least one metal element selected from the group consisting of , Sn, P, Ti, and Zr.