JP2002198067A - High-temperature operating solid polymer composite electrolyte membrane, membrane/electrode bonded body and fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-temperature operating solid polymer composite electrolyte membrane of excellent durability and low cost. SOLUTION: Metal oxide hydrate as represented by a hydrate of tungsten oxide or molybdenum oxide as a proton carrier and a heat-resistant molecular film which chemically modifies an organic polymer or an organic molecule and an inorganic molecule of nanometer level are conjugated to form an electrolyte membrane, which gives birth to a composite electrolyte membrane of an inorganic polymer and an organic polymer having durability comparable to, or more than, that of a desired fluorine based electrolyte membrane or practically enough durability and showing a practical level of proton conductivity which has a substantially high ion conductivity at high temperature range of around 160 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolyte membrane, a fuel cell using the same, and an apparatus using the fuel cell.

[0002]

2. Description of the Related Art A solid polymer electrolyte is a solid polymer material having an electrolyte group such as a sulfonic acid group in a polymer chain.
It has the property of firmly binding to specific ions and selectively transmitting cations or anions. Thereby, it is formed into particles, fibers or membranes, and is used for various applications such as electrodialysis, diffusion dialysis, and battery diaphragm.

In a solid polymer electrolyte fuel cell using such a solid polymer electrolyte, a pair of electrodes is provided on both sides of a proton conductive solid polymer electrolyte membrane, and low molecular hydrocarbons such as methane and methanol are provided. Is supplied to one electrode (fuel electrode) as a fuel gas. Further, oxygen gas or air is supplied to the other electrode (air electrode) as an oxidant.

[0004] Hydrogen gas supplied to the fuel electrode electrochemically generates protons at the fuel electrode and emits electrons. The generated protons move in the electrolyte membrane and react with oxygen and electrons in the air supplied at the air electrode to generate water. At this time, electrons are generated on the fuel electrode side and electrons are consumed on the air electrode side, and power is obtained by connecting an external load circuit.

[0005] Water electrolysis is a method for producing hydrogen and oxygen by electrolyzing water using a solid polymer electrolyte membrane.

As the proton conductive solid polymer electrolyte membrane, there is a fluorine-based electrolyte membrane represented by a perfluorocarbon sulfonic acid membrane proposed by DuPont, Dow, Asahi Kasei, Asahi Glass, and the like. Since it is excellent in chemical stability, it is used as a fuel cell used under severe conditions or as an electrolyte membrane for water electrolysis.

[0007] Salt electrolysis is a method for producing sodium hydroxide, chlorine and hydrogen by electrolyzing an aqueous sodium chloride solution using a solid polymer electrolyte membrane.

According to this, since the solid polymer electrolyte membrane is exposed to chlorine and a high-temperature, high-concentration sodium hydroxide aqueous solution, a hydrocarbon-based electrolyte membrane having poor durability to these aqueous solutions cannot be used. Therefore, the solid polymer electrolyte membrane for salt electrolysis is generally durable against chlorine and high-temperature, high-concentration sodium hydroxide aqueous solution, and is partially coated on the surface to prevent back diffusion of generated ions. A perfluorosulfonic acid membrane into which a carboxylic acid group has been introduced is used.

Incidentally, a fluorine-based electrolyte represented by a perfluorosulfonic acid membrane has a very high chemical stability because of having a C—F bond, and is used for the above-mentioned fuel cell, water electrolysis, or salt electrolysis. As a solid polymer electrolyte membrane for
Further, it is sometimes used as a solid polymer electrolyte membrane for hydrohalic acid electrolysis. Further, it is widely applied to a humidity sensor, a gas sensor, an oxygen concentrator, etc. by utilizing proton conductivity.

However, the fluorine-based electrolyte has a complicated manufacturing process and is very expensive, so that it is used only for special applications such as a polymer electrolyte fuel cell for space or military use, and low price is required. However, it has been difficult to apply it to polymer electrolyte fuel cells as a low-pollution power source for automobiles, small distributed power sources for consumers, and portable power sources.

Further, the fluorinated electrolyte membrane has a relatively low hydration power since it uses a sulfonic acid group as an ion carrier, and the electrolyte membrane is dried under a temperature environment higher than the boiling point of water and below a saturated water vapor pressure. Occurs and the resistance rises. Therefore, the operating temperature of the fuel cell is limited to 100 ° C. or lower, preferably 80 ° C. or lower.

[0012] Such a situation is a great limitation in realizing a fuel cell power generation system. That is, when the operating temperature is 80 ° C. or less, a step of removing carbon monoxide generated when producing hydrogen by steam reforming or partial oxidation of the raw fuel is required. In addition, since the level of the exhaust heat of the battery is low, there is a problem that the cogeneration system cannot utilize heat sufficiently.

Therefore, various attempts have hitherto been made to obtain a solid polymer electrolyte membrane having oxidation resistance degradation characteristics equal to or higher than that of a fluorine-based electrolyte membrane and which can be manufactured at low cost.

For example, Japanese Patent Application Laid-Open No. 9-102322 discloses that a main chain formed by copolymerization of a fluorocarbon vinyl monomer and a hydrocarbon vinyl monomer, and a hydrocarbon side chain having a sulfonic acid group. A sulfonic acid type polystyrene-graft-ethylenetetrafluoroethylene (ETFE) copolymer membrane has been proposed.

The ETFE copolymer membrane is inexpensive, has sufficient strength as a solid polymer electrolyte membrane for a fuel cell, and can be obtained by increasing the amount of sulfonic acid groups introduced.
It is possible to improve conductivity.

However, in the sulfonic acid type polystyrene-graft-ETFE membrane, the main chain portion formed by copolymerization of a fluorocarbon-based vinyl monomer and a hydrocarbon-based vinyl monomer has high oxidation-deterioration resistance, but a sulfonic acid group is introduced. The side chain portion is a hydrocarbon polymer which is susceptible to oxidative degradation. Therefore, when this is used for a fuel cell, there is a problem that the oxidation resistance of the whole membrane is insufficient and the durability is poor.

US Pat. No. 4,012,303 and US Pat. No. 4,605,685 disclose α, β in a film formed by copolymerization of a fluorocarbon vinyl monomer and a hydrocarbon vinyl monomer. , Β-trifluorostyrene is graft-polymerized, and a sulfonic acid group is introduced into the sulfonic acid type poly (trifluorostyrene) -graft-
ETFE films have been proposed.

This is because, in order to increase the chemical stability of the polystyrene into which the sulfonic acid group has been introduced, a partially fluorinated α, instead of styrene constituting the main chain is used.
β, β-trifluorostyrene is used.

However, α, which is a raw material for the side chain portion,
Since it is difficult to synthesize β, β-trifluorostyrene, there is a problem that the cost is high as in the case of Nafion as a solid polymer electrolyte membrane for a fuel cell. In addition, α, β, β-trifluorostyrene has a low polymerization reactivity, so that a small amount of α, β, β-trifluorostyrene can be introduced as a graft side chain, and there is a problem that the resulting film has low conductivity.

Further, since the above-mentioned membrane has a relatively low glass transition point and the sulfonic acid group is an ion conduction site, it has a low
In an environment having a high water vapor pressure such as exceeding 00 ° C., when the relative humidity is reduced, the ionic conductivity of the membrane is significantly reduced. For this reason, there is a problem that the device operating in a high temperature region cannot be used essentially.

[0021]

The problem to be solved by the present invention is as follows.
An object of the present invention is to provide an electrolyte membrane having practically sufficient durability.

Another object of the present invention is to provide a low-cost electrolyte membrane having sufficiently high ionic conductivity even at a high temperature range of about 100 ° C. and exhibiting a practical level of proton conductivity. In particular, it is to provide a composite electrolyte membrane of an inorganic polymer and an organic polymer exhibiting proton conductivity.

[0023]

According to the present invention, which achieves the above object, a proton conductive composite electrolyte membrane is composed of a metal oxide hydrate having proton conductivity and an organic polymer.

The metal oxide hydrate is composed mainly of tungsten oxide hydrate (WO ₃ .nH ₂ O) or molybdenum oxide hydrate (MoO ₃ .nH ₂ O). is there.

A membrane component mainly composed of tungsten oxide hydrate (WO ₃ .nH ₂ O) or molybdenum oxide hydrate (MoO ₃ .nH ₂ O) having proton conductivity is composed of ethylene oxide / propylene oxide monomer. The mixture is dispersed and mixed, and polymerized by photopolymerization to form a film.

Further, the proton conductive composite electrolyte membrane is a membrane / electrode assembly for a polymer electrolyte fuel cell comprising a polymer electrolyte membrane and a gas electrode joined to the polymer electrolyte membrane. is there.

The membrane / electrode assembly for a polymer electrolyte fuel cell comprises a polymer electrolyte membrane and a pair of gas diffusion electrodes comprising a cathode electrode and an anode electrode on both sides of the polymer electrolyte membrane. A pair of gas-impermeable separators is provided so as to sandwich the electrode, and a pair of sealing materials are arranged so as to be in contact with the outer peripheral portion of the gas electrode between the solid polymer electrolyte membrane and the separator. .

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a composite inorganic material having excellent oxidation resistance suitable for a proton ion conductive electrolyte membrane used for a fuel cell, water electrolysis, a humidity sensor, a gas sensor, etc., low cost and high durability. The present invention relates to a polymer electrolyte, a highly durable solid inorganic polymer electrolyte membrane using the same, and a fuel cell using the same.

The present inventors have focused on a proton conductive inorganic polymer material and studied an electrolyte membrane in which the proton conductive inorganic polymer material is combined with a heat-resistant organic polymer material.
An electrolyte membrane is obtained by mixing and dispersing metal oxide hydrates represented by hydrates of tungsten oxide and molybdenum oxide and ethylene oxide / propylene oxide monomers having excellent heat resistance as a matrix material for forming the film. Was.

By using the above-mentioned electrolyte membrane, a highly durable solid polymer electrolyte membrane which is equal to or more than the above-mentioned fluorine-based electrolyte membrane, or has practically sufficient deterioration resistance, and can be manufactured at low cost is provided. it can.

Further, the temperature is higher than 100 ° C., for example, 16 ° C.
A composite electrolyte membrane of an inorganic polymer and an organic polymer exhibiting a practical level of proton conductivity having sufficiently high ionic conductivity even at a high temperature range of about 0 ° C. has been realized. Embodiments of the present invention are as follows.

The hydrate of tungsten oxide or molybdenum oxide, which is a proton carrier, may be any water-soluble metal oxide. In particular, sodium tungstate and sodium molybdate are preferred raw materials.

These aqueous solutions are added dropwise to an acidic aqueous solution such as hydrochloric acid while cooling, and the resulting solid is washed with a weakly acidic aqueous solution, filtered, and then dried to be synthesized.

In forming this into a film, for example,
Ethylene oxide / propylene oxide monomer,
A sufficiently pulverized metal oxide hydrate powder is mixed and dispersed, and a photopolymerization initiator is added to the mixture to cast it into a film. Irradiation with ultraviolet rays or the like is performed to promote polymerization of the matrix, whereby a polyethylene oxide / propylene oxide polymer film in which metal oxide hydrate is dispersed can be obtained.

When the polymer electrolyte used in the present invention is used for a fuel cell, it is generally used in the form of a membrane, but is not limited thereto. For example,
It is also possible to use a cylindrical shape. That is, a method in which a dispersion mixture of the inorganic oxide hydrate serving as the proton carrier and the polymer matrix material is directly casted into a film, or the dispersion mixture is impregnated into a porous core material, woven fabric or nonwoven fabric. A method such as casting can be used. In particular, the method using a core material is advantageous in reducing the effective resistance of the electrolyte membrane since the obtained film can be thinned by using a high-strength core material.

The thickness of the polymer electrolyte membrane is not particularly limited, but is preferably from 10 to 200 μm. Practical 30-1
00 μm is more preferred. It is preferable that the thickness be greater than 10 μm in order to obtain a film strength that can withstand practical use, and it is preferable that the thickness be smaller than 200 μm in order to reduce the film resistance, that is, to improve the power generation performance. The film thickness can be controlled by the solution concentration or the coating thickness on the substrate.

Further, in producing the electrolyte of the present invention, additives such as a plasticizer, a stabilizer and a release agent which are used for ordinary polymers can be used within a range not inconsistent with the object of the present invention.

A gas diffusion electrode used in a membrane / electrode assembly when used as a fuel cell is an electrode layer in which a conductive material carrying fine particles of a catalytic metal is applied on an electrolyte membrane or formed into a membrane in advance. It is composed by bonding. This may contain a water repellent or a binder as necessary.

Further, a layer composed of a conductive material not carrying a catalyst, a water repellent and a binder may be formed outside the catalyst layer.

The catalyst metal used for the gas diffusion electrode may be any metal that promotes the oxidation reaction of hydrogen and the reduction reaction of oxygen. For example, platinum,
Gold, silver, palladium, iridium, rhodium, ruthenium, iron, cobalt, nickel, chromium, tungsten,
Manganese, vanadium, or alloys thereof are mentioned.

Among such catalysts, a binary system of platinum and ruthenium is often used, particularly for the cathode and platinum for the anode. The particle size of the catalyst metal is usually 1
0 to 300 angstroms. The amount of catalyst supported is
In a state where the electrode is formed, for example, 0.01 to 10 mg
/ Cm ² .

As the conductive material, any material may be used as long as it is an electron conductive material, and examples thereof include various metals and carbon materials. Examples of the carbon material include furnace black, channel black, carbon black such as acetylene black, activated carbon, and graphite. These may be used alone or as a mixture.

As the water repellent, for example, fluorinated carbon or the like is used.

As the binder for forming the catalyst layer, the electrolyte matrix polymer of the present invention is preferably used as it is, but other various resins may be used. In that case, a fluorine-containing resin having water repellency is preferable, in particular, heat resistance, those having excellent oxidation resistance are more preferable, for example, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, and Examples include a tetrafluoroethylene-hexafluoropropylene copolymer.

The method for bonding the electrolyte membrane and the electrode when used as a fuel cell is not particularly limited, and a known method can be applied.

As a method for producing a membrane / electrode assembly, for example, a platinum catalyst powder is mixed with a polytetrafluoroethylene suspension,
It is applied to carbon paper and heat-treated to form a catalyst layer. Next, there is a method in which the same electrolyte solution as the electrolyte membrane is applied to the catalyst layer, impregnated, and integrated with the electrolyte membrane by hot pressing.

In addition, the solution of the electrolyte membrane according to the present invention is
A method in which a coating of a platinum catalyst powder in advance is applied to an electrolyte membrane, a method in which a solution and a catalyst of the electrolyte membrane according to the present invention are pasted and applied to the electrolyte membrane, a method of electrolessly plating electrodes on the electrolyte membrane, and an electrolyte. There is a method in which a platinum group metal complex ion is adsorbed on the film and then reduced.

The polymer electrolyte fuel cell is provided outside the joined body of the electrolyte membrane and the gas diffusion electrode formed as described above.
With a grooved current collector that forms a fuel flow path and an oxidant flow path,
A unit in which a fuel distribution plate and an oxidant distribution plate are arranged is defined as a single cell. FIG. 1 shows an outline of this configuration.

A stack is formed by stacking a plurality of such single cells via a cooling plate or the like.

It is desirable to operate the fuel cell at a high temperature because the catalytic activity of the electrode increases, the electrode overvoltage decreases, and the electrode is less poisoned by carbon monoxide. However, since the electrolyte membrane does not function without moisture, it must be operated at a temperature at which moisture can be controlled.

The electrolyte according to the present invention has a higher water retention than conventional electrolyte membranes, and the preferable temperature range of the operating temperature of the fuel cell allows a temperature range from room temperature to 160 ° C.

[0052]

EXAMPLES The present invention will be described in more detail with reference to Examples. The output performance evaluation of the single cell of the fuel cell was performed as follows.

The electrolyte with the electrodes joined was incorporated into an evaluation cell, and the output performance of the fuel cell was evaluated. Hydrogen / oxygen was used as a reaction gas, and both were humidified at a pressure of 1 atm through a water bubbler at 70 ° C., and then supplied to an evaluation cell.

The gas flow rate was 60 ml / min of hydrogen, 40 ml / min of oxygen, and the cell temperature was 70 ° C. The battery output performance was evaluated using a H201B charge / discharge device (manufactured by Hokuto Denko).

Synthesis of Tungsten Oxide Hydrate 450 ml of a 3N hydrochloric acid aqueous solution is placed in a glass container, and the mixture is stirred at 5 ° C. and cooled. On the other hand, 50 ml of a 1 M aqueous solution of sodium tungstate Na ₂ WO ₄ is prepared, and this is dropped into the above hydrochloric acid aqueous solution using a microtube pump. The cooling rate is adjusted by adjusting the dropping speed so that the temperature of the mixed solution does not rise sharply.

The resulting precipitate was treated with a 0.1N hydrochloric acid aqueous solution 2
Wash well with 50 ml and water and filter. The obtained solid was dried using a desiccator. After drying, a portion of this sample was chemically analyzed and identified as tungsten oxide hydrate H ₂ WO ₄ .nH ₂ O (n = 1.03).

Preparation of Electrolyte Membrane The product obtained above was mixed with ethylene oxide / propylene oxide at a concentration of 80/20 so as to have a concentration of 15% by weight.
Was dispersed and mixed in the monomer mixed in the above. To this solution was added 0.3% by weight of azobiscyclohexanecarbonitrile as a photopolymerization initiator and cast on glass,
Irradiation was performed with an ultraviolet lamp to form an electrolyte membrane having a thickness of 42 μm. The ionic conductivity of the obtained film was measured at a temperature of 80 ° C.
0.02 S / cm, 150 at a relative humidity of 80%
It was 0.08 S / cm under the conditions of ° C and 60% relative humidity.

FIG. 2 shows the temperature dependence of the ionic conductivity under the condition of the saturated steam pressure, and FIG. 3 shows the dependency of the ionic conductivity on the steam partial pressure at each temperature. From these results, 160
It has been found that it has high conductivity in a high temperature range up to 100 ° C. and has sufficiently high ionic conductivity in a temperature range exceeding 100 ° C. even at a relative humidity of 60%.

Preparation of Membrane / Electrode Assembly The above-mentioned mixed solution of dimethylformamide-cyclohexanone-methylethylketone at a concentration of 5% by weight was mixed with 40% by weight of platinum-supported carbon at a weight ratio of platinum catalyst to polymer electrolyte of 2: 1. , And uniformly dispersed to prepare a paste. This paste was applied to both sides of the electrolyte membrane obtained above, and then dried to achieve a platinum loading of 0.1.
A 5 mg / cm ² membrane / electrode junction was made.

A packing material (supporting current collector) made of thin carbon paper, which has been made water-repellent with PTFE in advance, is brought into close contact with both sides of the membrane / electrode assembly. A single cell of a polymer electrolyte fuel cell comprising a conductive separator (bipolar plate) also serving as a role was produced.

This was subjected to a performance evaluation test under the conditions of an operating temperature of 90 ° C., a relative humidity of 80% at the fuel electrode entrance, and a current density of 150 mA / cm ² , and as a result, a voltage of 0.61 V was obtained.

As a result of disassembling the battery after the evaluation test and observing it, the membrane / electrode assembly was partially deformed around the seal portion, but there was no particular change in the appearance, and the ion conduction resistance was not changed. No change was seen.

Next, a mixed solution of dimethylformamide-cyclohexanone-methylethylketone having a concentration of 5% by weight was added so that the weight ratio of the platinum catalyst to the polymer electrolyte was 2: 1, and the mixture was uniformly dispersed to prepare a paste. did.

This paste was applied to both sides of the electrolyte membrane obtained above, dried and dried to obtain a platinum loading of 0.5 mg /
A membrane / electrode assembly of cm ² was made.

A packing material (supporting current collector) made of thin carbon paper which has been subjected to a water-repellent treatment with PTFE in advance is brought into close contact with both sides of the membrane / electrode assembly, from which both sides the electrode chamber is separated and the role of a gas supply passage to the electrodes is provided. A solid polymer electrolyte fuel cell unit cell was prepared, which was composed of a conductive separator (bipolar plate) that also served as a fuel cell.

The cell was subjected to a performance evaluation test under the conditions of an operating temperature of 90 ° C., a relative humidity of 80% at the entrance of the fuel electrode, and a current density of 150 mA / cm ^2. As a result, a voltage of 0.61 V was obtained.

As a result of disassembling and observing the battery after the evaluation test, the membrane / electrode assembly was partially deformed around the seal portion, but there was no particular change in the appearance and the ion conduction resistance. No change was seen.

[0068]

The composite electrolyte membrane of a metal oxide hydrate having proton conductivity and an organic polymer according to the present invention is lower in cost than a fluorine-based electrolyte membrane represented by a perfluorosulfonic acid membrane and can be used at high temperatures. It is an electrolyte membrane having sufficiently high ionic conductivity.

A membrane / electrode assembly using the above membrane, and
A fuel cell exhibits practically sufficient stability, and can provide a low-cost cell.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a cello structure of a polymer electrolyte fuel cell according to the present invention.

FIG. 2 is a graph showing the temperature dependence of the ionic conductivity of the electrolyte membrane of the present invention at a saturated water vapor pressure.

FIG. 3 is a graph showing the relative humidity dependence of the ionic conductivity at each temperature of the electrolyte membrane of the present invention.

[Explanation of symbols]

1, 2 ... separator, 3 ... cathode side current collector, 4 ... anode side current collector, 5 ... electrolyte membrane, 6 ... cathode gas sulfuric channel,
7 ... Anode gas sulfur channel.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) C08L 101/00 C08L 101/00 H01B 1/06 H01B 1/06 A 1/12 1/12 Z H01M 8/10 H01M 8 / 10 (74) One of the above-mentioned sub-agents 100068504 Patent Attorney Katsuo Ogawa (1 outside) (72) Inventor Yuichi Kamo 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Kenshi Yamaga 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Tetsuichi Kudo 7-22-4, Roppongi, Minato-ku, Tokyo (72) Invention Person Masaru Miyayama 7-22-4 Roppongi, Minato-ku, Tokyo 1-4 term, Umezono, Ichigo, F-term (reference) in Electronic Technology Research Institute, Industrial Technology Institute 4J002 CH021 DE096 GQ02 4J005 AA04 BB01 5G301 CA30 CD01 5H026 AA06 CX04 EE11 EE18

Claims (7)

[Claims] 1. A proton conductive composite electrolyte membrane comprising a proton conductive metal oxide hydrate and an organic polymer. 2. The metal oxide hydrate is mainly composed of tungsten oxide hydrate (WO ₃ .nH ₂ O) or molybdenum oxide hydrate (MoO ₃ .nH ₂ O). 3. The proton conductive composite electrolyte membrane according to item 1. 3. An ethylene oxide / propylene oxide monomer comprising a component mainly composed of tungsten oxide hydrate (WO ₃ .nH ₂ O) or molybdenum oxide hydrate (MoO ₃ .nH ₂ O) having proton conductivity. A proton conductive composite electrolyte membrane characterized in that it is dispersed and mixed into a polymer and formed into a film by photopolymerization. 4. In a membrane / electrode assembly for a polymer electrolyte fuel cell comprising a polymer electrolyte membrane and a gas electrode joined to the polymer electrolyte membrane, the polymer electrolyte membrane is characterized in that: A membrane / electrode assembly for a polymer electrolyte fuel cell, which is the proton conductive composite electrolyte membrane of 2 or 3. 5. In a membrane / electrode assembly for a polymer electrolyte fuel cell comprising a polymer electrolyte membrane and a gas electrode joined to the polymer electrolyte membrane, the polymer electrolyte membrane is characterized in that: 4. A membrane / electrode assembly for a polymer electrolyte fuel cell, which is the proton conductive composite electrolyte membrane according to any one of the above items 3, wherein a gas electrode is bonded to the electrolyte membrane. 6. A solid polymer electrolyte membrane, and a pair of gas diffusion electrodes comprising a cathode electrode and an anode electrode on both sides of the membrane, and a pair of gas-impermeable separators sandwiching the gas diffusion electrodes. Is installed, further, in a solid polymer electrolyte fuel cell sandwiched between the solid polymer electrolyte membrane and the separator, and a pair of sealing materials are arranged so as to be in contact with the outer peripheral portion of the gas diffusion electrode, A polymer electrolyte fuel cell, wherein the polymer electrolyte membrane and a pair of gas diffusion electrodes comprising a cathode electrode and an anode electrode on both sides thereof are a polymer polymer fuel cell membrane / electrode assembly. 7. A membrane / electrode assembly for a polymer electrolyte fuel cell, comprising: a polymer electrolyte membrane; and a pair of gas diffusion electrodes comprising a cathode electrode and an anode electrode arranged on both sides of the membrane. A solid polymer electrolyte membrane and a pair of gas diffusion electrodes consisting of a cathode electrode and an anode electrode on both sides thereof are arranged, and a pair of gas-impermeable separators are provided so as to sandwich the gas diffusion electrode. A polymer electrolyte fuel cell, comprising a pair of seal materials sandwiched between a polymer electrolyte membrane and said separator, and in contact with an outer peripheral portion of said gas diffusion electrode.