JPH09180730A - Electrode for solid high molecular fuel cell and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid high molecular fuel cell, of which catalyst bed has the ideal distribution and which has high performance, by forming the catalyst bed so that the electrolyte is contained at a larger rate on the surface side thereof than other parts thereof. SOLUTION: A catalyst bed 15 to be formed on a gas diffused layer 14 is formed of a first layer 16 including the electrolyte at a small ratio, a second layer 17 containing the electrolyte at an intermediate ratio, and a third layer 18 containing the electrolyte at a large ratio. As a method for slanting the rate of the electrolyte in relation to the catalyst powder, the electrolyte is added for mixing to the catalyst powder at a different rate of addition so as to manufacture two or more kinds of raw material mixture, and these two kinds or more of raw material mixture is mixed so as to form the suspension, and this suspension is deposited for carrying on the gas diffused layer 16 by filtering. At the time of filtering the catalyst suspension, plural raw material mixture is relatively divided for lamination by a difference of specific gravity. Distribution of the catalyst bed in the process can be thereby realized, and the electrode manufacturing process can be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell electrode and a method for manufacturing the same, and more particularly, to (A) a catalyst layer containing catalyst powder and an electrolyte on a gas diffusion layer made of carbon or other material, or ( B) An electrode for a polymer electrolyte fuel cell of the type in which a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent is deposited and supported, and a method for producing the same.

[0002]

2. Description of the Related Art Solid polymer electrolyte fuel cells are characterized in that an ionic conductor, that is, an electrolyte is a solid and a polymer. Specific examples of the solid polymer electrolyte include an ion exchange resin membrane. Both electrodes of the negative electrode and the positive electrode are arranged with the electrolyte membrane sandwiched between them.For example, hydrogen is supplied to the negative electrode side, and oxygen or air is supplied to the positive electrode side to cause an electrochemical reaction to cause electrolysis. Generate. In this case, as both the negative electrode and the positive electrode in contact with the solid polymer electrolyte membrane, there is a type in which platinum, palladium or other catalyst is added and used to accelerate the reaction, and this type of electrode is used. Various manufacturing methods have been proposed so far.

For example, in US Pat. No. 3,134,697,
The catalyst particles are mixed with an ion exchange resin to form an electrode sheet,
A method of thermocompression bonding this to an ion exchange resin membrane as a solid polymer electrolyte is described, and US Pat. No. 329748.
No. 4 and U.S. Pat. No. 3,432,355 describe a method in which catalyst particles are mixed with polytetrafluoroethylene to form an electrode sheet, which is then thermocompression bonded to an ion exchange resin membrane. However, just by joining the solid polymer electrolyte membrane and the electrode sheet as they are by thermocompression bonding or the like, the reaction site (reaction region) is limited to the two-dimensional interface between the electrolyte and the electrode, and the substantial working area is reduced. Few.

As one of the techniques for improving this, it has been proposed to increase the number of contact points between the electrode material and the solid electrolyte material to make the reaction site three-dimensional. For example, “Electrochemistry” 53, No. 10 (1985); 812-81
According to No. 7, NAFION-1 which is a kind of perfluorocarbon sulfonic acid resin membrane as a solid polymer electrolyte membrane.
Using 17 membranes (trade name, manufactured by Du Pont),
A platinum electrode is bonded to one side of the AFION film by an electroless plating method (permeation method) to form a hydrogen electrode (anode, fuel electrode), while an oxygen electrode (air electrode) that constitutes the counter electrode of this electrode, that is, a cathode side electrode. Is manufactured by the following steps.

First, platinum black powder or carbon powder carrying 10% platinum was used as catalyst powder, and Amberlite IR-120B (T-3) [styrene-divinylbenzene sulfonic acid resin, Na type, granules] Sutra 30
μm powder, manufactured by Organo, trade name] or NAFI
ON-117 [perfluorocarbon sulfonic acid resin (H type), 5% solution in a mixed solvent of aliphatic alcohol and water, manufactured by Aldrich Chemical Co., trade name]
Are mixed in various mixing ratios.

Next, polytetrafluoroethylene was added to each mixture obtained above in the form of an aqueous suspension and kneaded, and then the kneaded product was rolled by a roll to form a sheet, which was vacuum dried and then the electrode was formed. The sheet is applied to a NAFION membrane as a solid polymer electrolyte at a temperature of 100 ° C. and a pressure of 210.
It is hot pressing at kg / cm ² . And there, NAFIO as a solid polymer electrolyte membrane
By mixing an ion exchange resin into the oxygen electrode integrally bonded to the N film, the electrode reaction site is made three-dimensional and the polarization characteristics are remarkably improved.

In the above technique, all of the electrode sheets are manufactured by forming a kneaded material of the electrode material into a sheet by a method such as rolling. Another mode is also used in which a porous paper or sheet is separately used and catalyst particles are carried on the porous paper or sheet. For example, in JP-A-4-162365, a mixture of carbon black particles carrying a platinum catalyst and carbon black particles carrying no catalyst is used as a fine powder for forming a sheet-like catalyst layer, and the particles are used as a polymer electrolyte (ion exchange resin). )
The particle mixture is sprayed on a water repellent carbon paper as a base material, and is pressed by heating to adhere the carbon paper.

In the electrode sheet thus obtained, the water-repellent carbon paper forms a gas diffusion layer, and the layer of coated catalyst particles adhered on one side of this becomes a catalyst layer, which is incorporated into a fuel cell. Causes the catalyst layer side to contact the polymer electrolyte membrane surface. As a method of adhering the catalyst layer onto the gas diffusion layer, in addition to such a pressing method, a coating method, a roll method, a doctor blade method, etc. can be applied, but it is difficult to increase the area by the coating method. In addition, the roll method and the doctor blade method not only require various troubles, but also the apparatus itself is expensive.

For this reason, the present inventor has found that, as a method of adhering the coated catalyst particles onto the gas diffusion layer, the catalyst particles are applied onto the gas diffusion layer (such as water repellent carbon paper) by applying a filtering method. Attention was paid to a method of pouring an aqueous solution for forming a catalyst layer containing the solution and performing pressure filtration or suction filtration, and the results related to this were previously developed and filed (Japanese Patent Laid-Open No. 7-130377).

The invention according to the above-mentioned application is a method for producing an electrode for a polymer electrolyte fuel cell, in which a catalyst particle coated with a polymer electrolyte is coated on a catalyst particle made of water-repellent carbon paper or the like as a substrate. When a suspension mixed with a dispersion of a tetrafluoroethylene-based polymer is applied in a filtration mode, the suspension is dispersed in dilute sulfuric acid. This technique is an improvement of this technique, focusing on the suspension itself in this way, but this improves the characteristics of the electrode obtained through this process and, in turn, significantly improves the battery performance. There is.

By the way, in the above filtration method, the adhesion of the catalyst particles to the surface of the water-repellent carbon paper or the like is made more reliable, and the particles are mixed into the surface of the water-repellent carbon paper or the like. Therefore, it is possible not only to just pour the dispersion liquid in that way, but also to perform so-called suction filtration in which the pressure is reduced from below or pressure in above.
For example, in the Nutze (Buchner funnel) type or the like, there is a limit in the scale or size, and it is difficult to form a uniform layer and it is difficult to increase the area of the treated surface.

In order to solve such a problem, the inventor of the present invention manufactures an electrode for a fuel cell in which a catalyst layer is carried on a gas diffusion layer, and the hollow cylindrical body and its upper surface are formed into a funnel. A method and an apparatus for manufacturing a fuel cell electrode have been previously developed in which a solution containing catalyst particles is uniformly deposited on a gas diffusion layer by applying pressure filtration using a lower plate formed in a shape of ( Japanese Patent Application No. 6-309931).
1 and 2 show one embodiment of the method and apparatus for manufacturing the fuel cell electrode.

In FIG. 1, reference numeral 1 denotes a hollow cylindrical body whose cross-sectional shape is not limited to a circular shape as shown in FIG. 2 (a), and a square, pentagonal or other polygonal shape can be used. .
The hollow cylindrical body 1 is arranged in a vertical shape as shown in FIG. 2 (a), but as the material thereof, an appropriate material such as glass or metal can be used. In FIG. 1, 2 is an upper plate, 3 is a lower plate, 4 and 5 are upper and lower packings, respectively, and 6 is a compressor. Of these, the upper and lower packings 4 and 5 are configured to match the shape of the upper and lower peripheral portions of the hollow cylindrical body. For example, when the hollow cylindrical body has a cylindrical shape, the packings 4 and 5 correspond to the upper and lower peripheral portions thereof. It is configured in an annular shape.

In addition, the upper plate 2 is provided with a pipe (with a valve) 7 for introducing a solution to be filtered and a pipe (with a valve) 8 for discharging air when the pressure is excessive, and a compressor 6 for increasing the internal pressure in the container. A pipe 9 for introducing the compressed air is connected. 10 is a solvent outlet provided in the central portion of the lower plate 3, 1
Reference numeral 1 is a leg portion integrally attached to the lower plate 3, and 12 is a gas diffusion plate on which a catalyst layer is deposited from a solution. The gas diffusion plate 12 is sandwiched between the lower opening edge of the hollow cylindrical body 1 and the packing 5, and the solute in the solution, that is, catalyst particles is deposited on the upper surface of the packing 5 as a filter.

The lower plate 3 is preferably formed in a funnel shape as shown by a dotted line in FIG. 2 (b). This allows the solvent after filtration to flow smoothly. Lower plate 3
By configuring the upper surface of the above in a funnel shape in this manner, the solvent after filtration smoothly flows toward the solvent outlet, in contrast with other configurations such as the hollow cylindrical body 1. Even if a distribution of the thickness of the deposit is generated during the operation, the flow becomes poor in the thick portion and the deposition rate of the catalyst particles decreases, so that a uniform layer can be formed as a whole. The degree of the inclination can be appropriately set within a limit necessary for obtaining such an effect.

In operating the above apparatus, a solution containing catalyst particles in the hollow cylindrical body 1 is supplied from its container via a conduit 7 and compressed air is introduced by a compressor 6 to form a hollow cylindrical body. The inside of 1 is operated under pressure. In this case, the degree of pressurization depends on the scale of the apparatus (diameter, height, etc. of the hollow cylinder 1), fluidity of the solution containing the catalyst particles,
The gas diffusion plate 12 itself can be appropriately selected depending on various properties such as strength and the degree of the funnel-shaped inclination of the upper surface of the lower plate 3. Normally, for example, the hollow cylindrical body 1 has a diameter of 30 cm and a height of 5 cm.
In the case of about 0.1 kg / cm ² G (gauge pressure) or less.

According to the above electrode manufacturing method and apparatus to which pressure filtration is applied, it is possible to obtain an excellent electrode which is uniform and has a good gas diffusion performance even in a large area of 100 cm ² or more. Further, there is also an advantage that the pores through which the solvent passes during the production thereof become a gas diffusion path, and further, this device has an excellent effect such as being extremely inexpensive as compared with other catalyst layer film forming devices. . The gas diffusion plate (layer) also serves as a base material of the electrode itself, and as this material, water repellent carbon paper is preferably used. The water-repellent carbon paper is made of carbon paper having a predetermined thickness and porosity, which is impregnated with, for example, a polytetrafluoroethylene-based dispersion and then heat-treated to be water-repellent.

Further, as the solution containing catalyst particles, a suspension obtained by mixing platinum black particles or platinum-supporting carbon black particles with a solution of a solid polymer electrolyte, and a binder (water repellent) A solution for forming a catalyst layer, such as a suspension obtained by mixing a polytetrafluoroethylene-based polymer, is used as the agent).
If the suspension is used in which it is dispersed in a dilute sulfuric acid aqueous solution as in the invention of No. 30377, an effect having both effects can be obtained.

By the way, the above-mentioned raw materials of the catalyst layer are the catalyst powder, the water repellent agent and the electrolyte, of which the electrolyte is mixed to increase the electrode reaction points. In the pressure filtration method, the three components are made into a slurry using water as a solvent and deposited on the gas diffusion layer by the pressure filtration method, whereby the above-described excellent advantageous effects are obtained. However, in such a prior art or the prior art, this electrolyte is uniformly mixed in the catalyst layer, so that on the surface of the catalyst layer where the reaction points are desired to be increased, the proportion of the electrolyte is smaller than the desired proportion, and the increase On the side of the diffusion layer that does not need to be made, the ratio of the electrolyte was higher than the desired ratio.

[0020]

Therefore, the present invention deposits (A) a catalyst layer containing a catalyst powder and an electrolyte or (B) a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent on a gas diffusion layer. In producing an electrode for a fuel cell by supporting the same, it is an object to provide an electrode for a polymer electrolyte fuel cell in which the distribution of the electrolyte in the catalyst layer is biased to the surface, and a method for producing the same. .

[0021]

That is, the present invention is a fuel cell electrode comprising a gas diffusion layer carrying a catalyst layer containing catalyst powder and an electrolyte, wherein the electrolyte distribution in the catalyst layer is biased to the surface. A fuel cell electrode comprising a solid polymer electrolyte membrane fuel cell electrode characterized by comprising: a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent on a gas diffusion layer. Thus, there is provided an electrode for a polymer electrolyte fuel cell, characterized in that the electrolyte distribution in the catalyst layer is biased to the surface.

Further, according to the present invention, in producing a fuel cell electrode in which a catalyst layer containing a catalyst powder and an electrolyte is carried on a gas diffusion layer, a mixture of two or more kinds having different amounts of the electrolyte with respect to the catalyst powder is mixed. To provide a slurry, and depositing the slurry on the gas diffusion layer by a filtration method to bias the distribution of the electrolyte in the catalyst layer to the surface, thereby providing an electrode manufacturing method for a polymer electrolyte fuel cell. .

Further, in the present invention, in producing a fuel cell electrode in which a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent is carried on a gas diffusion layer, the catalyst powder and the electrolyte for the water repellent agent are used. A solid polymer characterized in that a mixture of two or more kinds having different amounts is mixed into a slurry, and the slurry is deposited on the gas diffusion layer by a filtration method to bias the electrolyte distribution in the catalyst layer on the surface. A method of manufacturing an electrode for a fuel cell for a fuel cell.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The above-mentioned gas diffusion layer also serves as a base material of the electrode itself, and the gas diffusion layer in the present invention is not particularly limited, and a porous paper or sheet made of various materials (see the present specification). In the description, both of them are appropriately referred to as "paper"), or these papers can be used after being made water repellent, and particularly preferably carbon paper or water repellent carbon paper can be used. Among them, the water-repellent carbon paper is a carbon paper having a predetermined porosity and thickness, which is impregnated with a polytetrafluoroethylene-based dispersion and then heat-treated to be water-repellent. is there. Here, the polytetrafluoroethylene-based polymer is meant to include not only polytetrafluoroethylene (PTFE) but also tetrafluoroethylene-hexafluoropropylene copolymer and other derivatives thereof.

As the catalyst powder, platinum black powder,
Platinum alloy powder, carbon black powder supporting platinum or palladium, palladium black powder and the like can be used. The water repellent agent is not particularly limited, but is preferably a polytetrafluoroethylene-based polymer. Here, the polytetrafluoroethylene-based polymer is meant to include not only polytetrafluoroethylene but also tetrafluoroethylene-hexafluoropropylene copolymer and other derivatives thereof.

As the above-mentioned electrolyte (polymer electrolyte), various ion exchange resins can be used, but it is advantageous to use a perfluorocarbon sulfonic acid-based resin exhibiting high performance as the electrolyte, and particularly a solid polymer electrolyte membrane. When a NAFION-based perfluorocarbon sulfonic acid-based resin film is used as above, it is preferable to use the same type of perfluorocarbon sulfonic acid-based resin. The solvent is not particularly limited, such as water, alcohol, or a mixture of the two, but water is preferable when a filtration method, especially a pressure filtration method, is applied at the time of deposition on the gas diffusion layer.

In the present invention, (A) in the catalyst layer containing the catalyst powder and the electrolyte, or (B) on the gas diffusion layer.
In the catalyst layer containing the catalyst powder, the electrolyte and the water repellent, the proportion of the electrolyte is biased and deposited and carried. In the case of (A), it is performed by mixing two or more kinds of raw material mixtures having different amounts of electrolyte with respect to the catalyst powder, and depositing the mixed suspension, that is, slurry, on the gas diffusion layer by a filtration method. You can In this case, as a method of biasing the proportion of the electrolyte with respect to the catalyst powder, two or more kinds of raw material mixtures are prepared by adding and mixing the electrolyte to the catalyst powder so that the addition proportions thereof are different from each other. This can be carried out by mixing a mixture of one or more raw materials to form a suspension, and depositing and supporting the suspension on the gas diffusion layer by a filtration method.

Further, as the catalyst layer, the above (B) catalyst powder,
When a catalyst layer containing an electrolyte and a water repellent agent, that is, a catalyst layer containing a water repellent agent together with a catalyst powder and an electrolyte is formed, a mixture having a constant amount ratio of the catalyst powder and the water repellent agent is used. On the other hand, two or more types of raw material mixtures were prepared by adding and mixing electrolytes with different addition ratios, and further mixing these two or more types of raw material mixtures to form a suspension. It can be carried out by depositing and supporting on the layer by a filtration method.

FIG. 3 shows the distribution of the electrolyte in the catalyst layer formed on the gas diffusion layer when three raw material mixtures having different electrolyte addition ratios are mixed and used as a suspension according to this embodiment. It is a schematic diagram for explaining. FIG.
Among them, 13 is an electrode, 14 is a gas diffusion layer, and 15 is a catalyst layer. The portions indicated by reference numerals 16 to 18 are the catalyst layer 1
5 shows the state of distribution of the electrolyte in 5, wherein 16 is a layer with a small amount of electrolyte (first layer), 17 is a layer with an electrolytic mass between 16 and 18 (second layer), and 17 is a layer with a large amount of electrolyte (third layer). Layer).

In this way, during the filtration operation of the catalyst suspension onto the gas diffusion layer, the three kinds of raw material mixtures are relatively separated into three layers due to the difference in specific gravity, and the first layer and the second layer are laminated. And between the second layer and the third layer are not as clear as shown in the figure, and catalyst particles having different electrolysis masses enter each other,
The electrolytic mass is deposited as a continuously distributed layer. In this case, in order to further improve the distribution, it is preferable to mix and use at least three or more raw material mixtures having different electrolyte mixing ratios, and it is desirable to sufficiently perform this mixing operation. Thus, according to the present invention, the ideal distribution of the catalyst layer can be realized in one step, and
It is possible to realize simplification of the electrode manufacturing process.

Next, one aspect of the specific procedure of the present invention is as follows (a) to (e).
(A) For example, an aqueous mixture of 50% platinum-supported catalyst particles, polytetrafluoroethylene, and an electrolyte is prepared. At this time, the mixing ratio (weight ratio) of these catalyst particles, polytetrafluoroethylene, and electrolyte is set to, for example, 4: 3 :.
2, 4: 3: 3, and 4: 3: 4. (B) The raw materials having the three types of mixing ratios thus obtained are mixed by a colloid mill to form a suspension. (C) On the other hand, for example, a porosity of 75
%, 0.4 mm thick carbon paper is impregnated with, for example, a dispersion of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and then heat treated to obtain a water repellent carbon paper in which FEP accounts for 20%. Create. (D), the mixed solution prepared in (a) to (b) is sprinkled on the water repellent carbon paper prepared in (c), the catalyst layer is formed by filtering the solvent, and the solvent is removed by vacuum drying or the like. To do. (E) A solid polymer electrolyte membrane is sandwiched between two produced electrodes and pressed to obtain a battery.

[0032]

EXAMPLES Examples of the present invention will be described below, but it goes without saying that the present invention is not limited to these examples. As the apparatus used, a pressure filtration type apparatus as shown in FIGS. 1 and 2 was used. The hollow cylindrical body 1 has an inner diameter of 15c
A hollow cylindrical body made of glass and having a height of 8 cm and a height of 8 cm was used, and the internal pressure during operation was 0.08 kg / cm ² G (gauge pressure).

(1) First, the surface area is 180 cm ² , and the porosity is 7
A 5% carbon paper having a thickness of 0.4 mm was impregnated with a dispersion of NEOFLON (a tetrafluoroethylene-hexafluoropropylene copolymer, a registered trademark of Daikin Industries, Ltd.), followed by heat treatment, and water repellency with NEOFLON. The carbonized paper was obtained. In this case, the quantitative proportion was adjusted so that neofron constituted 20% by weight in the total amount. (2) On the other hand, catalyst particles in which carbon particles carry 50% platinum, dispersion of polyflon (polytetrafluoroethylene, registered trademark of Daikin Industries, Ltd.) and ethanol solution of perfluorocarbon sulfonic acid resin as an electrolyte, Mixing ratio (weight ratio) of these catalyst particles, polytetrafluoroethylene and electrolyte
Were made to be 4: 3: 2, 4: 3: 3, and 4: 3: 4, respectively. (3) The raw material mixtures having three types of mixing ratios thus obtained were mixed in a colloid mill for about 1 hour to obtain a suspension.

(4) Next, the water repellent carbon paper obtained in (1) is set as indicated by reference numeral 12 in FIG. 1 and obtained from the solution supply conduit 7 in FIG. 1 by (2) to (3). The above aqueous suspension was supplied, the platinum was deposited so that the amount of platinum supported was 1 mg / cm ^2, and the solvent was removed by vacuum drying (temperature 80 ° C.). The electrode sheet for the examples was obtained. (5) A perfluorocarbon sulfonic acid-based resin film having a film thickness of 80 μm is sandwiched between the two electrodes thus produced with the catalyst layer sides of both electrodes in contact with the polymer electrolyte membrane surface, and the temperature is 140 ° C. and pressure is applied. After pressing for 60 seconds under a pressure of 100 kgf / cm ² , this was assembled in a fuel cell frame and set, and a conducting wire, a gas pipe and the like were connected to obtain a test battery for an example.

Comparative Example On the other hand, with respect to the water repellent carbon paper produced in the same manner as in the above (1), FIGS.
An electrode was produced by applying the pressure filtration method under the same conditions as above using the apparatus shown in FIG. In this case, as the catalyst particles, the water repellent agent (polytetrafluoroethylene) and the material of the electrolyte, the same materials as those used in the examples are used, and the mixing amount of these catalyst particles, polytetrafluoroethylene and the electrolyte is used. Mix so that the ratio (weight ratio) is 4: 3: 3,
A suspension obtained by mixing the mixture with a colloid mill for about 1 hour was used. The same solid polymer electrolyte membrane as in the above example was sandwiched between the catalyst layers of the two electrodes thus produced, and pressed under the same conditions as above, and the same configuration as in the case of the above example was used as a comparative test battery. .

Using the various test cells manufactured as described above, hydrogen was used as the fuel, and this was supplied to the anode side, while air was supplied to the cathode side. The supply pressure of both gases is 2 atm, hydrogen is 95 ° C., air is 80 ° C., and the battery temperature is 80 ° C.
The measurement was performed by keeping the temperature at 0. FIG. 4 shows the relationship between the cell density and the current density measured for each of the above test batteries.

As shown in FIG. 4, even in the test battery of the comparative example, the cell voltage gradually decreased with the increase of the current density, but it was considerably superior in the test battery of the example. It can be seen that the trend is even slower and further improved. As described above, according to the present invention, the characteristics of the polymer electrolyte fuel cell can be improved more effectively. Furthermore, the ideal distribution of the catalyst layer is realized in one step, and the manufacturing process can be simplified.

[0038]

As described above, according to the present invention, due to the difference in specific gravity due to the difference in the amount of electrolyte during filtration and deposition in the gas diffusion layer, the surface side of the catalyst layer has a large proportion of electrolyte, An electrode whose ratio decreases as it approaches the diffusion layer can be produced, and thus a polymer electrolyte fuel cell having higher performance can be obtained. Further, according to the present invention, the ideal distribution of the catalyst layer can be realized in one step, and the electrode manufacturing process can be simplified.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a pressure filtration type electrode manufacturing apparatus.

FIG. 2 is a view showing a hollow cylindrical body 1 and a lower plate 3 of FIG.

FIG. 3 is a schematic diagram for explaining a distribution state of an electrolyte in a catalyst layer formed on a gas diffusion layer according to the present invention.

FIG. 4 is a diagram showing the relationship between the measured current density and cell voltage of each test battery manufactured in Examples and Comparative Examples.

[Explanation of symbols]

 1 Hollow Cylindrical Body 2 Upper Plate 3 Lower Plate 4, 5 Packing 6 Compressor 7 Pipe for Introducing Solution to Be Filtered (with Valve) 8 Pipe for Emitting Air at Overpressure (with Valve) 9 Compressed Air Introducing Pipe 10 Solvent Discharge Outlet 11 Leg 12 Gas diffusion plate (layer) on which catalyst layer is deposited 13 Electrode 14 Gas diffusion layer 15 Catalyst layer 16 Low electrolyte layer 17 Layer between electrolytic mass 15 and 17 18 High electrolyte layer

Claims (10)

[Claims] 1. A fuel cell electrode comprising a gas diffusion layer and a catalyst layer containing a catalyst powder and an electrolyte supported thereon, wherein the electrolyte is distributed in the catalyst layer toward the surface. Electrodes for polymer fuel cells. 2. A fuel cell electrode in which a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent is carried on a gas diffusion layer, wherein the distribution of the electrolyte in the catalyst layer is biased to the surface. An electrode for a polymer electrolyte fuel cell, which is characterized by: 3. The electrode for a polymer electrolyte fuel cell according to claim 1, wherein the gas diffusion layer is carbon paper or water repellent carbon paper. 4. The solid polymer fuel cell electrode according to claim 1, wherein the catalyst particles are carbon powders carrying platinum. 5. The solid polymer fuel cell electrode according to claim 1, 2, 3 or 4, wherein the electrolyte is a perfluorocarbon sulfonic acid type resin. 6. When manufacturing a fuel cell electrode in which a catalyst layer containing a catalyst powder and an electrolyte is carried on a gas diffusion layer, a slurry is prepared by mixing a mixture of two or more kinds having different amounts of the electrolyte with respect to the catalyst powder. The method for producing an electrode of a polymer electrolyte fuel cell, wherein the slurry is deposited on the gas diffusion layer by a filtration method to bias the distribution of the electrolyte in the catalyst layer on the surface. 7. When manufacturing a fuel cell electrode in which a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent is carried on a gas diffusion layer, the amounts of the electrolyte with respect to the catalyst powder and the water repellent agent are different. A polymer electrolyte fuel cell characterized in that a mixture of two or more kinds is mixed into a slurry, and the slurry is deposited on the gas diffusion layer by a filtration method to bias the distribution of the electrolyte in the catalyst layer on the surface. For manufacturing electrodes for use. 8. The method for producing an electrode for a polymer electrolyte fuel cell according to claim 6, wherein the gas diffusion layer is carbon paper or water repellent carbon paper. 9. The method for producing an electrode for a polymer electrolyte fuel cell according to claim 6, 7 or 8, wherein the catalyst particles are carbon powder supporting platinum. 10. The method for producing an electrode for a polymer electrolyte fuel cell according to claim 6, 7, 8 or 9, wherein the electrolyte is a perfluorocarbon sulfonic acid type resin.