JP4610820B2 - Inorganic electrolyte membrane and inorganic electrolyte membrane fuel cell - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inorganic electrolyte membrane and a fuel cell using the inorganic electrolyte membrane.
More specifically, the present invention relates to an inorganic electrolyte membrane for a fuel cell that is excellent in high-temperature stability and excellent in stability capable of maintaining a high voltage even during long-term operation or high-temperature operation.
[0002]
TECHNICAL BACKGROUND OF THE INVENTION
In recent years, high efficiency, pollution-free CO using clean hydrogen as an energy source₂Fuel cells are attracting attention as power generation systems that do not generate isothermal gases. Such fuel cells have been fully developed and researched for use in fixed facilities such as homes and offices, and mobile facilities such as automobiles.
[0003]
Fuel cells are classified according to the electrolyte membrane used, and are divided into alkaline electrolyte membrane type, solid polymer electrolyte membrane type, phosphoric acid type, molten carbonate type, and solid electrolyte membrane type. At this time, in the solid polymer electrolyte membrane type and the phosphoric acid type, the charge transfer body is a proton, which is also called a proton type fuel cell.
Examples of the fuel used in the fuel cell include hydrocarbon fuels such as natural gas, LP gas, city gas, alcohol, gasoline, kerosene, and light oil.
[0004]
Such hydrocarbon fuel is first converted into hydrogen gas and CO gas by a reaction such as steam reforming and partial oxidation, and the CO gas is removed to obtain hydrogen gas. This hydrogen is supplied to the anode, dissociated into protons (hydrogen ions) and electrons by the metal catalyst of the anode, the electrons flow to the cathode while working through the circuit, and the protons (hydrogen ions) diffuse through the electrolyte membrane and become the cathode. In the cathode, the electrons, hydrogen ions, and oxygen supplied to the cathode are converted into water and diffused in the electrolyte membrane. That is, it is a mechanism for taking out an electric current in the process of supplying water with oxygen and hydrogen derived from fuel gas.
[0005]
As an electrolyte membrane used in such a fuel cell, a polystyrene-based cation exchange membrane having a sulfonic acid group, a mixed membrane of fluorocarbon sulfonic acid and polyvinylidene fluoride, a membrane obtained by grafting trifluoroethylene to a fluorocarbon matrix, A perfluorocarbon sulfonic acid membrane or the like is used.
However, the movement of protons in the electrolyte membrane made of such an organic resin membrane, that is, the ionic conductivity of the membrane depends on the moisture content in the membrane, and when operated for a long time or at a high temperature of about 80 ° C. or higher, The moisture content in the membrane decreases, resulting in a decrease in ionic conductivity,PressureThere was a problem such as causing a drop.
[0006]
For this reason, Japanese Patent Application Laid-Open No. 6-103983 discloses that a polymer film having a phosphoric acid group is included, thereby allowing the polymer film to exhibit good water retention performance. A solid polymer electrolyte membrane fuel cell that can be suitably used at the operating temperature has also been proposed.
Japanese Patent Application Laid-Open No. 2001-143723 discloses an electrolyte membrane for a fuel cell that can be suitably used at an operating temperature of 80 ° C. or higher, and is made of an amorphous silica molded body containing phosphorus pentoxide. ing.
[0007]
However, when these proposed solid polymer electrolyte membranes are used at a high temperature of 100 ° C. or higher for a long period of time, the moisture content of the membrane decreases due to the high temperature, or in the electrolyte membrane using a resin component, There is a problem in that the conductivity is lowered, the voltage is lowered, and the performance of the battery is lowered.
Therefore, as a result of intensive studies on means for improving battery performance by long-term use under such high temperature conditions, the present inventors have found that antimony oxide particles have high proton conductivity and high water retention at high temperatures. The present inventors have found that a fuel cell having high battery performance can be obtained even when used at a high temperature for a long period of time by constituting a solid electrolyte membrane from the antimony oxide particles and the inorganic matrix component, thereby completing the present invention. It came to.
[0008]
OBJECT OF THE INVENTION
An object of the present invention is to provide an inorganic electrolyte membrane capable of obtaining a fuel cell having high battery performance even when used under a high temperature for a long period of time.
[0009]
SUMMARY OF THE INVENTION
The inorganic electrolyte membrane according to the present invention comprises inorganic proton conductive oxide particles and an inorganic matrix component.
The inorganic proton conductive oxide particles are composed of hydrated antimony oxide particles represented by the following formula (1), the average particle diameter of the particles is in the range of 5 to 50 nm, and the hydrated antimony oxide particles are contained. Amount of oxide (Sb₂O_Five) In the range of 5 to 80% by weight in terms of conversion.
[0010]
Sb₂O_Five・ NH₂O (1)
n = 0.1-5
The inorganic matrix component is ZrO.₂, SiO₂, TiO₂, Al₂O_ThreeIt is preferable that it consists of 1 or more types of inorganic oxides chosen from these.
The fuel cell according to the present invention uses the inorganic electrolyte membrane.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the inorganic electrolyte membrane and the inorganic electrolyte membrane fuel cell according to the present invention will be described.
Inorganic electrolyte membrane
The inorganic electrolyte membrane according to the present invention comprises an inorganic matrix component and inorganic proton conductive oxide particles.
[0012]
[Inorganic proton conductive oxide particles]
Examples of inorganic proton conductive oxide particles used in the present invention include antimony oxide particles, heteropolyacids such as tungstic acid, stannic acid, and molybdic acid, crystalline aluminosilicates introduced with rare earth ions, porous crystalline aluminum phosphate, and the like. can give.
[0013]
Such inorganic proton conductive oxide particles are required to have high water retention performance, and are preferably hydrated antimony oxide particles represented by the following formula (1).
The hydrated antimony oxide particles used in the present invention are hydrates of antimony oxide and are represented by the following formula. (It is not crystal water, except for just adhering water)
Sb₂O_Five・ NH₂O (1)
n = 0.1-5
Antimony oxide particles have proton conductivity, and are blended to increase the conductivity of the inorganic electrolyte membrane.
[0014]
The average particle diameter of such hydrated antimony oxide particles is preferably in the range of 5 to 50 nm, more preferably 5 to 25 nm. When the average particle diameter is less than 5 nm, the powder resistance (volume resistance value) is 10^TenΩ · cm may be exceeded, and therefore the cation conductivity is low, so that a sufficient output voltage may not be obtained. If the average particle diameter exceeds the upper limit range, depending on the method for producing the inorganic electrolyte membrane, the hydrated antimony oxide particles may not be sufficiently introduced into the electrolyte membrane, and even if it can be introduced, the inorganic electrolyte membrane May be insufficient in strength.
[0015]
As the water content of the hydrated antimony oxide particles, the water content when dried at 100 ° C. for 1 hour is preferably in the range of about 0.5 to 22% by weight, more preferably 2 to 22% by weight.
Furthermore, it is preferable that the water content after drying at 200 ° C. is in the range of 0.25 to 10% by weight, more preferably 0.5 to 10% by weight.
[0016]
When the moisture content of the hydrated antimony oxide particles after drying at 200 ° C. is less than 0.25% by weight, the effect of using the hydrated antimony oxide particles as the inorganic proton conductive particles cannot be obtained. When the battery is operated for a long time, the voltage drops, and the battery performance tends to deteriorate.
It is difficult to obtain a product whose water content exceeds 10% by weight after drying at 200 ° C.
[0017]
In addition, the hydrated antimony oxide particles used in the present invention do not need to be in the moisture content range when used for the preparation of the inorganic electrolyte membrane. You can also.
The hydrated antimony oxide particles used in the present invention have a powder resistance (volume resistance value) of 10.^TenLess than Ω · cm, or even 10⁷It is preferably less than Ω · cm.
[0018]
The volume resistance value of the conductive oxide particles is 10^TenIf it exceeds Ω · cm, although depending on the content in the inorganic electrolyte membrane, the effect of keeping the electric resistance low may be insufficient and a sufficient output voltage may not be obtained.
[Inorganic matrix component]
Inorganic matrix components decompose at high temperatures and are ZrO₂, SiO₂, TiO₂, Al₂O_ThreeIt is preferable that it consists of 1 type, or 2 or more types of inorganic oxides chosen from these.
[0019]
When these inorganic matrix components are used, an inorganic electrolyte membrane that is porous and excellent in film strength, water retention and the like, as well as excellent in thermal stability and durability can be obtained.
As such an inorganic matrix component, Zr, Si, Ti, Al metal salts and / or hydrolysis / polycondensates of organometallic compounds are suitable.
Examples of the metal salt include chloride, sulfate, nitrate and the like.
[0020]
Examples of the organometallic compound include silicic acid solution, alkoxysilane, zirconium tetrabutoxide, silicon tetrapropoxide, titanium tetrapropoxide, and hydrolysates thereof.
Furthermore, the inorganic matrix component is further ZrO.₂ Sol, SiO₂ Sol, TiO₂ Sol, Al₂O_ThreeSol, SiO₂・ Al₂O_Three It may be formed from a conventionally known sol such as a composite sol.
[0021]
Among these inorganic matrix components, those composed of silica are preferred in the present invention, and in particular, a silicic acid solution obtained by dealkalizing an aqueous alkali metal silicate solution or an alkoxysilane represented by the following formula [1] Those formed from these organosilicon compounds are preferred.
R_aSi (OR ')_4-a            [1]
(In the formula, R is a vinyl group, an aryl group, an acrylic group, an alkyl group having 1 to 8 carbon atoms, a hydrogen atom or a halogen atom, and R ′ is a vinyl group, an aryl group, an acrylic group, or a carbon system having 1 to 8 carbon atoms. Alkyl group, -C₂H_FourOC_nH_{2n + 1}(N = 1 to 4) or a hydrogen atom, and a is an integer of 0 to 3. )
Such alkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraoctylsilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, methyltriisopropoxysilane, Examples include vinyltrimethoxysilane, phenyltrimethoxysilane, and dimethyldimethoxysilane.
[0022]
[Inorganic electrolyte membrane]
The inorganic electrolyte membrane according to the present invention includes the inorganic matrix component and inorganic proton conductive oxide particles.
The content of the inorganic proton conductive oxide particles in the inorganic electrolyte membrane is preferably in the range of 5 to 80% by weight, more preferably 30 to 75% by weight as the oxide.
[0023]
When the content of the inorganic proton conductive oxide particles is less than the lower limit, the resulting membrane has insufficient conductivity, the output voltage is lowered, and the inorganic proton conductive oxide particles have high water retention and conductivity. If the content of the inorganic proton conductive oxide particles exceeds the above upper limit, the strength of the electrolyte membrane from which a small amount of matrix components can be obtained may be insufficient.
[0024]
Furthermore, the inorganic electrolyte membrane used in the present invention can be used by blending a component having water retention performance as required. In addition to porous inorganic oxides such as silica / alumina, zeolite (crystalline aluminosilicate), clay minerals, titanium nanotubes, and other porous inorganic compounds having a high specific surface area, the component having water retention performance Fine particles of inorganic compounds modified with a sulfone group, a phosphate group, a carboxyl group, or the like can be suitably used.
[0025]
It is preferable that the amount of the component having such water retention performance is approximately in the range of 30% by weight or less in the inorganic electrolyte membrane.
The inorganic electrolyte membrane according to the present invention preferably has a thickness in the range of 0.01 to 10 mm, more preferably 0.05 to 5 mm.
When the thickness of the inorganic electrolyte membrane is less than 0.01 mm, sufficient membrane strength cannot be obtained, and cracks or pinholes may occur during processing.
[0026]
When the film thickness of the inorganic electrolyte film exceeds 10 mm, proton conductivity decreases, and sufficient film strength may not be obtained when the film is formed by a coating solution method.
As described above, since the inorganic electrolyte membrane is composed of the inorganic matrix component and the inorganic proton conductive oxide particles excellent in high-temperature water retention performance and conductivity, it is difficult to use a polymer membrane made of an organic resin. Even when operating at a high temperature of 100 ° C. or higher, a high output voltage can be stably maintained.
[0027]
The inorganic electrolyte membrane according to the present invention is usually porous and has a porosity of 5% or more, preferably 10% or more.
[Method for producing inorganic electrolyte membrane]
Such an inorganic electrolyte membrane is a coating for forming an inorganic electrolyte membrane in which a precursor of an inorganic matrix component that acts as a binder, inorganic proton conductive oxide particles, and component fine particles having water retention properties used as necessary are dispersed in a dispersion medium. Can be used.
[0028]
As the inorganic proton conductive oxide particles and the component fine particles having water retention performance used as necessary, the same fine particles as described above are used.
Examples of the precursor of the inorganic matrix component include the metal salts and organometallic compounds of Zr, Si, Ti, and Al described above, and these may be hydrolyzed or partially hydrolyzed. Further, as described above, ZrO₂ Sol, SiO₂ Sol, TiO₂ Sol, Al₂O_ThreeSol, SiO₂・ Al₂O_ThreeA composite sol or the like can also be used, and the hydrolyzate and sol can also be mixed and used.
[0029]
As the precursor of such an inorganic matrix component, a precursor made of a silica precursor is preferable, and specifically, a silicic acid solution obtained by dealkalizing an alkali metal silicate aqueous solution or represented by the formula [1]. Suitable are partial hydrolysates and hydrolysates of organosilicon compounds such as alkoxysilanes.
Examples of such alkoxylane include those described above.
[0030]
When one or more of the above alkoxysilanes are hydrolyzed in the presence of an acid catalyst, for example, in a water-alcohol mixed solvent, a dispersion of a precursor of a matrix component containing a hydrolysis polycondensate of alkoxysilane is obtained. The concentration of the precursor of the matrix component contained in the dispersion is 1 to 15% by weight, preferably 2 to 10% by weight in terms of oxide.
[0031]
A coating liquid for forming an inorganic electrolyte membrane is prepared by mixing and dispersing the dispersion liquid of the precursor of the inorganic matrix component, the inorganic proton conductive oxide particles, and the component fine particles having water retention performance, which are used as necessary, in a dispersion medium. Prepare. The amount of each component at this time is mixed so that the amount of each component in the obtained inorganic electrolyte membrane is in the above-described range.
[0032]
At this time, the total concentration of the inorganic matrix component precursor, the inorganic proton conductive oxide particles, and the component fine particles having water retention performance used as needed in the inorganic electrolyte membrane forming coating is 2 to 50% by weight as an oxide. Furthermore, it is preferable that it exists in the range of 5 to 30 weight%.
When the concentration of the coating for forming the inorganic electrolyte film is less than 2% by weight, although depending on the coating method, an inorganic electrolyte film having a desired film thickness may not be obtained by a single coating. If the concentration exceeds 50% by weight, the viscosity of the coating becomes high, making it difficult to form a coating. Even if it is obtained, the coating method may be limited, or the strength of the resulting inorganic electrolyte membrane may be insufficient.
[0033]
In the above, water is usually preferable as the dispersion medium, and an organic solvent can be used in combination. Organic solvents include methanol, ethanol, propanol, butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, alcohols such as ethylene glycol and hexylene glycol; esters such as acetic acid methyl ester and acetic acid ethyl ester; diethyl ether And ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; ketones such as acetone, methyl ethyl ketone, acetylacetone and acetoacetate. These may be used singly or in combination of two or more.
[0034]
Moreover, the coating material used by this invention can also deionize, concentrate as needed, or can mix | blend and use a sol.
An inorganic electrolyte membrane is formed using the above-described coating material for forming an inorganic electrolyte membrane, but the forming method is not particularly limited as long as it has power generation performance, strength of the membrane, etc. For example, there is a method in which a Teflon (R) mold is filled with a paint, followed by drying, heat treatment and the like.
[0035]
Alternatively, the inorganic electrolyte membrane-forming coating material may be applied onto a substrate by a spray method, a roll coater method, a flexographic printing method, or the like on a fuel cell electrode, followed by drying, heat treatment, etc. A film can be formed. According to this method, the electrode and the inorganic electrolyte membrane can be integrally manufactured.
In addition, after applying a dispersion of a precursor of an inorganic matrix component in advance to form a thin film composed of the inorganic matrix component, the inorganic proton conductive oxide particles and the component fine particles having water retention performance used as needed are dispersed. The inorganic electrolyte membrane according to the present invention can also be formed by spraying a dispersion liquid mixed and dispersed in a medium and then drying.
[0036]
Fuel cell
The fuel cell according to the present invention is characterized by using the above-described inorganic electrolyte membrane.
Specifically, it is composed of the above-described inorganic electrolyte membrane and a pair of gas diffusion electrodes (a fuel electrode and an oxidation electrode) disposed on both sides of the inorganic electrolyte membrane and sandwiching the inorganic electrolyte membrane between the fuel electrode and the oxidant electrode. A single cell is formed by arranging a current collector with a groove forming a fuel chamber and an oxidant chamber outside the two electrodes, and such a single cell is formed by laminating a plurality of layers via a cooling plate or the like. The
[0037]
The gas diffusion electrode is usually composed of a porous sheet in which a conductive material carrying catalyst particles is held by a hydrophobic resin binder such as PTFE. Further, a catalyst particle layer may be provided on the contact surface of the porous electrolyte sheet made of a conductive material and a hydrophobic resin binder such as PTFE.
A pair of such gas diffusion electrodes sandwich an inorganic electrolyte membrane and are crimped by a known crimping means such as hot press.
[0038]
Any catalyst may be used as long as it has a catalytic action on the oxidation reaction of hydrogen and the reduction reaction of oxygen. Platinum, ruthenium, iridium, rhodium, palladium, osnium, tungsten, lead, iron, chromium, cobalt, nickel, manganese, It can be selected from metals such as vanadium, molybdenum, gallium, aluminum, or alloys thereof.
[0039]
The conductive material may be any electron conductive material. For example, carbon black such as furnace black, channel black, and acetylene black known as carbon materials, activated carbon, graphite, and various metals can be used.
Examples of the hydrophobic resin binder include various resins containing fluorine, such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and perfluorosulfonic acid.
[0040]
As the hydrophobic resin binder, a proton conductive polymer may be used, and this polymer also has a function as a binder in the polymer itself, and it is sufficient for the catalyst particles and the conductive particles in the catalyst layer. It is possible to form a stable matrix.
A gas diffusion layer made of the hydrophobic resin binder may be provided on the opposite surface in contact with the inorganic electrolyte membrane.
[0041]
The amount of catalyst supported is 0.01 to 5 mg / cm with the catalyst layer sheet formed.²And more preferably 0.1-1 mg / cm²If it is.
The electrically conductive porous material has a specific surface area of 100 to 2000 m.²/ G is preferable for obtaining sufficient permeability. Moreover, it is preferable that the average pore diameter of a gas diffusion electrode is 0.01-1 micrometer.
[0042]
Furthermore, in the present invention, a proton conductive polymer layer may be formed at an interface where at least one of the catalyst layers is in contact with the inorganic electrolyte membrane.
In the fuel cell according to the present invention, hydrogen is supplied to the fuel chamber, air (oxygen) is supplied to the oxidant chamber, and electricity is generated by the following electrode reaction.
Fuel electrode (anode): H₂  → 2H⁺ + 2e^-
Oxygen electrode (cathode): 2H⁺ + 1 / 2O₂ + 2e^- → 2H₂O
In the antimony oxide particles in the inorganic electrolyte membrane, hydrogen is bonded to oxygen of the antimony oxide skeleton, is present in the state of water, or protons (H⁺) Or hydronium ion (H_ThreeO⁺) Is considered to exist.
[0043]
【The invention's effect】
According to the present invention, since the inorganic electrolyte membrane is composed of the inorganic matrix component and the inorganic proton conductive oxide particles having excellent high-temperature water retention performance and conductivity, the high temperature even when operated at a high temperature of 100 ° C. or higher. An inorganic electrolyte membrane fuel cell that is excellent in stability and can stably maintain a high output voltage even when operated at a high temperature for a long period of time can be provided.
[0044]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
[0045]
[Example 1]
Antimony pentoxide particles (average particle size 10 nm, Sb as inorganic proton conductive oxide particles)₂O_Five・ 2.5H₂O) and the concentration is Sb₂O_FiveAs a mixed solvent dispersion of 40% by weight of ethyl alcohol: water = 50: 50 was prepared. Ceramate 503 obtained by hydrolyzing methyltrimethoxysilane as a matrix component precursor (manufactured by Catalyst Kasei Kogyo Co., Ltd .: SiO)₂16% by weight) Sb₂O_Five: SiO₂= 50: 50, and the mixture was stirred at 50 ° C. for 1 hour to prepare an inorganic electrolyte membrane-forming coating material (A) having a total oxide concentration of 20.8% by weight.
[0046]
Next, a 10 cm × 10 cm Teflon (R) mold is filled with the inorganic electrolyte film-forming coating material (A), heated to 250 ° C. at a rate of 1 ° C./min, heated at 250 ° C. for 6 hours, and inorganic. An electrolyte membrane (A) was obtained. The film thickness of the inorganic electrolyte membrane (A) obtained by taking it out of the mold was 0.8 mm.
Next, a platinum-supported carbon particle having a platinum content of 40% by weight was mixed with a mixed solvent of ethyl alcohol: water = 50: 50 to make a paste, which was carbon paper (Toray ( (Made by Co., Ltd.) The platinum-supported carbon particles are 0.5 g / cm on each of the two sheets.²Then, it was applied so as to have a density of 1, and dried at 100 ° C. for 12 hours to prepare two gas diffusion electrodes (A).
[0047]
Two gas diffusion electrodes (A) are used as a positive electrode and a negative electrode, and an inorganic electrolyte membrane (A) is sandwiched between the two electrodes.²The unit cell (A) was prepared by bonding the gas diffusion electrode (A) and the inorganic electrolyte membrane (A) to each other by hot pressing at 300 ° C. for 4 minutes.
Evaluation
The unit cell (A) was humidified at 80 ° C. and a relative humidity of 30% for 2 hours. Next, current density of 0.5 A / cm at each temperature of 80 ° C., 100 ° C., 140 ° C., and 180 ° C. under normal pressure²The output voltage at each temperature at this time was measured, and the results are shown in Table 1.
[0048]
Further, as an evaluation of the high temperature durability, it was operated at 140 ° C. for 500 hours, the output voltage at this time was measured, and the results are shown in Table 1.
[0049]
[Example 2]
Antimony pentoxide particles (average particle size 10 nm, Sb as inorganic proton conductive oxide particles)₂O_Five・ 2.5H₂O) and the concentration is Sb₂O_FiveAs a mixed solvent dispersion of 30% by weight of ethyl alcohol: water = 50: 50 was prepared. Ceramate 503 obtained by hydrolyzing methyltrimethoxysilane as a matrix component precursor (manufactured by Catalyst Kasei Kogyo Co., Ltd .: SiO)₂16% by weight) and zirconia sol (manufactured by Daiichi Rare Element Co., Ltd .: average particle diameter 5 nm, ZrO₂ 25% by weight) Sb₂O_Five: SiO₂: ZrO₂= 50: 40: 10 were mixed and stirred at 50 ° C. for 1 hour to prepare an inorganic electrolyte membrane-forming coating material (B) having a total oxide concentration of 21.9% by weight.
[0050]
Next, a unit cell (B) was prepared in the same manner as in Example 1 except that the inorganic electrolyte film-forming paint (B) was used.
Evaluation
Using the unit cell (B), the output voltage was measured in the same manner as in Example 1, and the results are shown in Table 1.
[0051]
[Example 3]
Antimony pentoxide particles (average particle size 10 nm, Sb as inorganic proton conductive oxide particles)₂O_Five・ 2.5H₂O) and Sb₂O_FiveA mixed solvent dispersion of 30% by weight of ethyl alcohol: water = 50: 50 was prepared. Ceramate 503 obtained by hydrolyzing methyltrimethoxysilane as a matrix component precursor (manufactured by Catalyst Kasei Kogyo Co., Ltd .: SiO)₂16% by weight) and silica sol (manufactured by Catalyst Chemical Industry Co., Ltd .: SI-350, average particle size 7 nm, SiO₂20% by weight) Sb₂O_Five: SiO₂: SiO₂ Sol= 70: 20: 10 was mixed and stirred at 50 ° C. for 1 hour to prepare an inorganic electrolyte membrane-forming coating material (C) having a total oxide concentration of 24.5% by weight.
[0052]
Next, a unit cell (C) was prepared in the same manner as in Example 1 except that the inorganic electrolyte film-forming paint (C) was used.
Evaluation
Using the unit cell (C), the output voltage was measured in the same manner as in Example 1, and the results are shown in Table 1.
[0053]
[Example 4]
Antimony pentoxide particles (average particle diameter of 40 nm, Sb as inorganic proton conductive oxide particles)₂O_Five・ 2.5H₂A unit cell (D) was prepared in the same manner as in Example 1 except that O) was used.
Evaluation
Using the unit cell (D), the output voltage was measured in the same manner as in Example 1, and the results are shown in Table 1.
[0054]
[Example 5]
In the same manner as in Example 1, two gas diffusion electrodes (A) were prepared. On the surface of this one gas diffusion electrode (A) coated with platinum-supporting carbon,Example 1The inorganic electrolyte film-forming coating material (A) prepared in (1) was applied by a roll coater method, dried at 100 ° C. for 12 hours, and then heat-treated at 250 ° C. for 6 hours to form an inorganic electrolyte on the gas diffusion electrode (A). A membrane (E) was formed. The film thickness of the inorganic electrolyte membrane (E) was 0.2 nm.
[0055]
Next, the inorganic electrolyte membrane (E) is sandwiched between the other gas diffusion electrodes (A) and 20 kg / cm.²A unit cell (E) in which the gas diffusion electrode (A) and the inorganic electrolyte membrane (E) were joined was prepared by hot pressing at 300 ° C. for 4 minutes under the pressure of.
Evaluation
Using the unit cell (E), the output voltage was measured in the same manner as in Example 1, and the results are shown in Table 1.
[0056]
[Example 6]
Antimony pentoxide particles (average particle size 10 nm, Sb as inorganic proton conductive oxide particles)₂O_Five ・ 2.5H₂O)) and Sb₂O_FiveA mixed solvent dispersion of 30% by weight of ethyl alcohol: water = 50: 50 was prepared. Ceramate 503 obtained by hydrolyzing methyltrimethoxysilane as a matrix component precursor (manufactured by Catalyst Kasei Kogyo Co., Ltd .: SiO)₂16 wt.₂/ Al₂O_Three= 8, average particle diameter 0.8 μm) dispersion (SiO₂・ Al₂O_Three30% by weight) and Sb₂O_Five: SiO₂: (SiO₂・ Al₂O_Three) = 50: 30: 20, and the mixture was stirred at 50 ° C. for 1 hour to prepare an inorganic electrolyte membrane-forming paint (F) having a total oxide concentration of 23.7% by weight.
[0057]
Subsequently, a unit cell (C) was prepared in the same manner as in Example 1 except that the inorganic electrolyte film-forming paint (F) was used.
Evaluation
Using the unit cell (C), the output voltage was measured in the same manner as in Example 1, and the results are shown in Table 1.
[0058]
[Comparative Example 1]
Carbon paper (Toray Industries, Inc.) made by adding a mixed solvent of ethyl alcohol: water = 50: 50 to platinum-supported carbon particles having a platinum content of 40% by weight as Pt to make a paste, and water-repellent treatment with tetrafluoroethylene (Made by) The platinum-supported carbon particles are 0.5g / cm on each of the two sheets²Then, it was applied so as to have a density of 1, and dried at 100 ° C. for 12 hours to prepare two gas diffusion electrodes (A).
[0059]
Two gas diffusion electrodes (A) are used as a positive electrode and a negative electrode, and a perfluorocarbon sulfonic acid film (manufactured by DuPont: Nafion film N-117 film thickness 183 μm) is sandwiched between the two electrodes as an inorganic electrolyte film, and 150 Kg / cm²A unit cell (G) in which the gas diffusion electrode (A) and the inorganic electrolyte membrane were joined was prepared by hot pressing at 100 ° C. for 5 minutes under the pressure of.
[0060]
Evaluation
Using the unit cell (G), the output voltage was measured in the same manner as in Example 1, and the results are shown in Table 1.
[0061]
[Table 1]

Claims (3)

It consists of inorganic proton conductive oxide particles and inorganic matrix components,
Inorganic proton conductive oxide particles
Consists hydrated antimony oxide particles represented by the following formula (1), the average particle diameter of said particles Ri range near the 5 to 50 nm,
An inorganic electrolyte membrane , wherein the inorganic matrix component comprises one or more inorganic oxides selected from ZrO ₂ , SiO ₂ , TiO ₂ , and Al ₂ O ₃ .
Sb ₂ O ₅ · nH ₂ O (1)
n = 0.1-5 The inorganic electrolyte membrane according to claim 1, wherein the content of the hydrated antimony oxide particles is in the range of 5 to 80% by weight in terms of oxide (Sb ₂ O ₅ ).   An inorganic electrolyte membrane fuel cell comprising the inorganic electrolyte membrane according to claim 1 or 2.