JPH09180727A - Fuel cell electrode, manufacturing method and device thereof - Google Patents

Abstract

(57) Abstract: In addition to making the thickness of the catalyst layer of the electrode uniform and determining the optimum thickness arbitrarily, cracks are eliminated in the catalyst layer during heat treatment and drying process in the electrode manufacturing process, and higher performance is achieved. To obtain a battery having Kind Code: A1 An electrode for a fuel cell in which (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 is carried on a gas diffusion layer. A gas diffusion layer in which the catalyst layer comprises a high-viscosity slurry containing catalyst particles and a nonionic surfactant, or a high-viscosity slurry containing catalyst particles, a water repellent and a nonionic surfactant while controlling the film thickness. A fuel cell electrode, which is a catalyst layer obtained by applying a heat treatment to a substrate and then impregnating the coated surface with an electrolyte, and a method and apparatus for producing the same.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell electrode,
More specifically, the production method and the apparatus therefor include, on a gas diffusion layer, (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. TECHNICAL FIELD The present invention relates to a fuel cell electrode of a type, a manufacturing method and apparatus thereof.

[0002]

2. Description of the Related Art A fuel cell, for example, a solid polymer electrolyte type fuel cell is characterized in that an ionic conductor, that is, an electrolyte is a solid and a polymer. A resin film or the like is used, and both the negative electrode and the positive electrode are arranged with the electrolyte film 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. And generate electricity. In this case, for both the negative electrode and the positive electrode in contact with the solid polymer electrolyte membrane, there is a type in which platinum, palladium and other catalysts are added and used in order to accelerate the reaction. 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 roll rolling to form a sheet, which was vacuum dried and then the electrode sheet was formed. To a NAFION membrane as a solid polymer electrolyte membrane at a temperature of 100 ° C. and a pressure of 21
Hot pressing is performed at 0 kg / cm ² .
And there, NAFI as a solid polymer electrolyte membrane
By mixing an ion exchange resin into the oxygen electrode integrally bonded to the ON 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 produced by forming a kneaded product 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 for adhering the coated catalyst particles onto a gas diffusion layer such as water-repellent carbon paper, a method applying a filtering method, that is, the gas diffusion layer (water-repellent carbon paper) is used. Etc.), paying attention to a method of pouring an aqueous solution for forming a catalyst layer containing catalyst particles onto the mixture and carrying out pressure filtration or suction filtration, and the results related thereto have been previously developed and filed (JP-A-7-130377).
issue).

The invention according to the above-mentioned application is a method for producing an electrode for a polymer electrolyte fuel cell, wherein, for example, water repellent carbon paper is used as a base material and polytetrafluoroethylene is used as catalyst particles coated with the polymer electrolyte. When the suspension mixed with the dispersion of 1. is applied by filtration, it is performed by dispersing the suspension 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-mentioned filtration method, for example, the adhesion of the catalyst particles to the surface of the water repellent carbon paper is made more reliable, and the particles are mixed into the surface of the water repellent carbon paper. It is possible not only to just pour the dispersion liquid in that way, but also to perform it in a so-called suction filtration system in which the pressure is reduced from below, or in a system in which pressure is applied from above. Therefore, 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 present inventor has prepared a solution containing catalyst particles in a hollow cylindrical body in manufacturing an electrode for a fuel cell in which a catalyst layer is supported on a gas diffusion layer. And a lower plate whose upper surface is formed in a funnel shape, and has previously developed a method and an apparatus for manufacturing an electrode of a fuel cell in which a catalyst layer is uniformly deposited on a gas diffusion layer by applying pressure filtration. (Japanese Patent Application No. 6-309931).
1 to 2 show one embodiment of this electrode manufacturing method and apparatus.

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.
A quadrangle, a pentagon, or any other polygonal shape can also 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 the figure, 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 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 is cylindrical, the packings 4 and 5 have an annular shape corresponding to the upper and lower peripheral portions thereof. Is composed of.

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. Further, even if a distribution of the thickness of the deposit is generated during the operation, the flow becomes worse 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.

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 (also as an agent).
If the suspension is dispersed in a dilute sulfuric acid aqueous solution as in the invention of No. 97280, an effect having both effects can be obtained.

By the way, the raw materials for the catalyst layer described above are
(A) a catalyst powder and an electrolyte, or (B) a catalyst powder, an electrolyte and a water repellent agent, which are made into a slurry with water as a solvent, and are deposited on the gas diffusion layer by a pressure filtration method, thereby So effective and excellent effect can be obtained. However, when observing the catalyst layer thus obtained in more detail, water passes through during the filtration, so that a portion through which water passes remains in the catalyst layer (this also has an advantage that it also serves as a gas diffusion path. However, it was observed that this part was likely to cause aggregation of water during the operation of the battery, which was a factor inhibiting gas diffusion.

The present inventor has separately developed a method and apparatus for improving the above-mentioned drawbacks and improving the above-mentioned drawbacks, and manufacturing a fuel cell electrode having higher performance. This technique produces a fuel cell electrode in which (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 is carried on a gas diffusion layer. In this case, a high-viscosity slurry containing catalyst particles or a high-viscosity slurry containing catalyst particles and a water repellent agent is applied to the gas diffusion layer while controlling the film thickness, and then the coated surface is impregnated with an electrolyte. However, in the present invention,
By adding a nonionic surfactant to the above slurry, it was found that the characteristics of the electrode obtained through this and the performance of the fuel cell using the same can be further improved, and the present invention was reached. It is a thing.

[0021]

That is, the present invention provides a catalyst layer containing (A) catalyst powder and an electrolyte on a gas diffusion layer,
Alternatively, (B) in producing a fuel cell electrode having a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent, as a supporting method, a slurry having high viscosity containing catalyst particles or a catalyst particle and water repellent. A fuel cell having higher cell performance by adding a nonionic surfactant to a high-viscosity slurry containing an agent and applying (painting) the slurry on the gas diffusion layer. It is an object of the present invention to provide a use electrode, a method for manufacturing the same, and a device for the same.

[0022]

The present invention provides a fuel cell electrode comprising a gas diffusion layer carrying a catalyst layer containing catalyst powder and an electrolyte, the catalyst layer comprising catalyst particles and a nonionic surface active agent. A fuel characterized by being a catalyst layer obtained by applying a high-viscosity slurry containing an agent to the gas diffusion layer while controlling the film thickness, followed by heat treatment, and then impregnating the applied surface with an electrolyte. An electrode for a battery is provided.

The present invention also provides a catalyst powder on the gas diffusion layer,
A fuel cell electrode comprising a catalyst layer containing an electrolyte and a water repellent agent, wherein the catalyst layer has a high viscosity slurry containing catalyst particles, a water repellent agent and a nonionic surfactant. After applying to the gas diffusion layer while controlling, heat treatment,
Next, there is provided a fuel cell electrode, which is a catalyst layer obtained by impregnating the coated surface with an electrolyte.

The present invention also provides a catalyst layer containing (A) catalyst powder and an electrolyte on the gas diffusion layer, or (B) catalyst powder,
In producing a fuel cell electrode carrying a catalyst layer containing an electrolyte and a water repellent agent, a highly viscous slurry containing catalyst particles and a nonionic surfactant, or a catalyst particle, a water repellent agent and a nonionic slurry A method for producing an electrode for a fuel cell, which comprises applying a high-viscosity slurry containing a surfactant to a gas diffusion layer while controlling the film thickness, performing heat treatment, and then impregnating an electrolyte on the applied surface. It is provided.

The present invention also provides a catalyst layer containing (A) catalyst powder and an electrolyte on the gas diffusion layer, or (B) catalyst powder,
In producing a fuel cell electrode carrying a catalyst layer containing an electrolyte and a water repellent agent, a highly viscous slurry containing catalyst particles and a nonionic surfactant, or a catalyst particle, a water repellent agent and a nonionic slurry A highly viscous slurry containing a surfactant is applied to the gas diffusion layer while controlling the film thickness with a feeder equipped with one or more blades for controlling the film thickness, followed by heat treatment, and then an electrolyte is applied to the coated surface. Provided is a method for manufacturing an electrode for a fuel cell, which is characterized by being impregnated.

Further, the present invention is for a fuel cell in which (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 is carried on a gas diffusion layer. An electrode manufacturing apparatus, wherein one or a plurality of high-viscosity slurries containing catalyst particles and a nonionic surfactant, or a high-viscosity slurry containing catalyst particles, a water repellent and a nonionic surfactant. An electrode for a fuel cell, characterized in that a gas diffusion layer is coated on a gas diffusion layer while controlling the film thickness by a feeder equipped with a blade for controlling the thickness, then heat-treated, and then the coated surface is impregnated with an electrolyte. To provide a manufacturing apparatus.

[0027]

There are various types of fuel cells, such as phosphoric acid type, alkaline type, solid polymer type, and the like. The electrode of the present invention, its manufacturing method and apparatus are applicable to any of these fuel cell electrodes. Can be applied. Next, the gas diffusion layer also serves as a base material of the electrode itself, and as this material, a porous paper or sheet made of various materials (in this specification, both are appropriately referred to as "paper"). Or water-repellent carbon paper can be used, and carbon paper or water-repellent carbon paper can be preferably used. Among them, the water-repellent carbon paper is a carbon paper having a predetermined porosity and thickness, which is impregnated with a dispersion of a polytetrafluoroethylene-based polymer and then heat-treated to be water-repellent. Is. Here, the polytetrafluoroethylene-based polymer is meant to include not only polytetrafluoroethylene (PTFE) but also a tetrafluoroethylene-hexafluoropropylene copolymer and other derivatives thereof.

As the catalyst powder, platinum black powder, platinum alloy powder, platinum- or palladium-supported carbon black powder, palladium black powder or the like can be used. The water-repellent agent used in the present invention 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.

The nonionic surfactant (nonioni)
c Surfactant) is not particularly limited as long as it is nonionic, such as polyethylene glycol alkyl ether, polyethylene glycol fatty acid ester, sorbitan fatty acid ester, and fatty acid monoglyceride.
In relation to the heat treatment after applying the slurry described below, the temperature is 360 ° C.
It is desirable that it decomposes at a heat treatment temperature of about a certain degree or less. Further, it is not limited to one kind, and two or more kinds of nonionic surfactants may be used in combination.

In a preferred embodiment of the present invention, one slurry having a high viscosity containing catalyst particles and a nonionic surfactant, or one slurry having a high viscosity containing catalyst particles, a water repellent and a nonionic surfactant is used. Coating is performed while controlling the film thickness on the gas diffusion layer by a feeder equipped with a plurality of blades for controlling the film thickness. The viscosity of the slurry is sufficient if it does not flow and diffuse to the periphery of the diffusion layer after coating and can be controlled by the feeder.
Preferably 1000 to 10,000 cp (centipoise)
It is a degree.

Further, in the present invention, after coating the slurry to a predetermined thickness, the coating surface is impregnated with an electrolyte. As the electrolyte, various ion exchange resins and the like can be used, but perfluorocarbon sulfonic acid type resins are preferably used. Among the fuel cells, for example, in the case of a solid polymer type fuel cell, when using a perfluorocarbon sulfonic acid type resin membrane as the solid polymer electrolyte membrane, it is recommended to use this same type of perfluorocarbon sulfonic acid resin. preferable.

FIG. 3 is a diagram showing an embodiment of an electrode manufacturing method and apparatus according to the slurry coating method of the present invention. In FIG.
Reference numeral 13 is a rotating roller, 14 is a diffusion layer made of, for example, carbon paper or water repellent carbon paper, 15 is a slurry feeder, 16 is a front blade (front blade) that constitutes the feeder 15, and 17 is the same feeder 15.
And the front blade 16 and the rear blade 17 together control the supply amount of the slurry and the thickness of the coating layer. In the embodiment of FIG. 3, the front blade 16 and the rear blade 17 are
The blades for control are formed by one piece or three or more pieces depending on various characteristics such as fluidity and viscosity of the slurry. Reference numeral 18 is a catalyst layer formed after coating, and S is a slurry for forming a catalyst layer, that is, a slurry containing a catalyst powder and a nonionic surfactant, or a catalyst powder, a water repellent and a nonionic surfactant. It is a slurry.

Regarding the operation of this apparatus, the feeder 1
5 (including: the front blade 16 and the rear blade 17) is supplied with the slurry S as shown in FIG. 3 to adjust the thickness of the catalyst layer 18 to be applied while adjusting the heights of the front blade 16 and the rear blade 17 while rotating the roller. The diffusion layer 14 made of carbon paper, water repellent carbon paper, or the like is moved by rotating 13 in the direction of the arrow in the drawing (direction from right to left in FIG. 3). As a result, the catalyst layer 18 having a predetermined thickness is formed on the diffusion layer 14. At this time, the heights of the front blade 16 and the rear blade 17 are adjusted so that the thickness of the catalyst layer coated on the diffusion layer 13 is a desired thickness. Control to be

The above-mentioned raw material slurry is applied, for example, by the blade or blade type application method as described above. Therefore, the raw material slurry needs to have a predetermined viscosity, and as described above, it can be applied with a viscosity of about several thousand to 10,000 cp (centipoise). In addition, as in the above embodiment, the diffusion layer 1
Instead of moving 4, the diffusion layer 14 is fixed by an appropriate supporting member, and the feeder 15 (including: 16 and trailing blade 17) is moved relatively to the fixed diffusion layer 14. It doesn't matter.

Next, one mode of the specific procedure of the present invention is as follows (a) to (f). (A)
For example, 50% platinum-supported catalyst particles and PTFE dispersion are mixed so that the catalyst particles and polytetrafluoroethylene are, for example, 4: 3 (weight ratio),
About 0.5-2% by weight of nonionic surfactant is added to this mixture. (B) The obtained mixture is mixed with a colloid mill, and the solvent is heated to increase the concentration of the mixture so that the viscosity becomes about 1000 to 10000 cp. Water is preferably used as the solvent, but ethanol may be partially contained in the solvent.

(C) Carbon paper, water repellent carbon paper, etc. are set as shown in FIG. 3, and the slurry liquid prepared as described in (a) and (b) above is supplied to the portion of slurry S in FIG. To do. While adjusting the gap between the surface of the water repellent carbon paper or the like and the front blade 16 and the rear blade 17, the paper 14 is moved by the rotating roller 13 to apply the slurry liquid. (D) The coating layer was heated at a temperature of 360 in a nitrogen stream.
Heat treatment is performed at about ℃ to thermally decompose and remove the surfactant. (E) Next, the coated surface is impregnated with an electrolyte solution, and the solvent is removed by vacuum drying or the like to obtain an electrode.
(F) A solid polymer electrolyte membrane is sandwiched between the produced electrodes and pressed to obtain a battery.

[0037]

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, the apparatus shown in FIG. 3 was used.

(1) First, the surface area is 100 cm ² , and the porosity is 8
A 0%, 0.4 mm thick carbon paper was impregnated with a dispersion of NEOFLON (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, the catalyst particles in which 50% platinum is supported on carbon particles and the dispersion of polyflon (polytetrafluoroethylene, a registered trademark of Daikin Industries, Ltd.) are mixed with the catalyst particles and polytetrafluoroethylene in a ratio of 4: 3 ( (Weight ratio), and mixed with this mixture as a nonionic surfactant, Nissan Nonion NS-20.
4.5 (polyoxyethylene nonyl phenyl ether,
1% by weight of NOF CORPORATION, trade name) was added. The mixture thus obtained is mixed in a colloid mill and the solvent (water) is heated and evaporated to increase the concentration of the mixture, and the viscosity is about 80.
It was made to be a slurry of 00 cp.

(3) Next, the water repellent carbon paper obtained in (1) is set as shown in 14 in FIG. 3, and the slurry liquid prepared in (2) above is supplied to the portion of the slurry S in FIG. did. While adjusting the gap between the water repellent carbon paper 14 and the front blade 16 and the rear blade 17, the rotating roller 13 was rotated as shown by the arrow in FIG. In this case, the film thickness was such that the amount of platinum supported was 1 mg / cm ² . (4) The coating layer was heat-treated in a nitrogen stream at a temperature of 360 ° C. to thermally decompose and remove the surfactant. (5) Next, the coated surface was impregnated with an ethanol solution of perfluorocarbon sulfonic acid resin, and the solvent was removed by vacuum drying to obtain an electrode.

(6) A solid polymer electrolyte membrane (perfluorocarbon sulfonic acid resin membrane) having a film thickness of 80 μm was sandwiched between the two electrodes thus produced, with the catalyst layer sides of both electrodes being in contact with the membrane surfaces. , Temperature 140 ℃, pressure 100kgf / c
After pressing for 60 seconds under a pressure of m 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 of the example.

Comparative Example On the other hand, (2) the catalyst particles in which the carbon particles were loaded with 50% platinum and the dispersion of polyflon (polytetrafluoroethylene, a registered trademark of Daikin Industries, Ltd.) were used as the catalyst particles. And the polytetrafluoroethylene are mixed in a ratio of 4: 3 (weight ratio), the nonionic surfactant is not added to the mixture, and the step (4) related thereto is not performed. Except for this, batteries other than the above were manufactured in the same manner as in the example, and used as the test battery for the comparative example.

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 comparative test battery, the cell voltage was only gradually decreased as the current density was increased.
It can be seen that the decreasing tendency is slower and further improved. During the process of manufacturing the electrodes used in the examples, after the heat treatment and after drying, the surface was observed with an electron microscope, and it was confirmed that there was no crack in the process of heat treatment or drying. As described above, according to the present invention, even when the catalyst layer of the electrode has a large area, the electrode characteristic and the battery characteristic using the same can be more effectively improved.

[0044]

As described above, according to the present invention, since the thickness of the catalyst layer of the electrode is fixed by the blade, it is possible to make the thickness uniform. Further, in addition to being able to arbitrarily determine the optimum thickness, it is possible to obtain a fuel cell which has no cracks in the catalyst layer during the heat treatment or drying process in the electrode manufacturing process and has higher performance.

[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 diagram showing an embodiment of an electrode manufacturing method and apparatus applicable in 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 Rotating roller 14 Gas diffusion layer 15 Feeder for slurry 16 Front blade of feeder (front blade) 17 Rear blade of feeder (rear blade) 18 Coated catalyst layer S Catalyst layer forming slurry

Claims (12)

[Claims] 1. A fuel cell electrode comprising a gas diffusion layer carrying a catalyst layer containing a catalyst powder and an electrolyte, wherein the catalyst layer comprises a highly viscous slurry containing catalyst particles and a nonionic surfactant. A fuel cell electrode, which is a catalyst layer obtained by coating a gas diffusion layer while controlling the film thickness, heat-treating it, and then impregnating the coated surface with an electrolyte. 2. A fuel cell electrode comprising a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent on a gas diffusion layer, the catalyst layer comprising catalyst particles, a water repellent agent and a nonionic. A catalyst layer obtained by applying a high-viscosity slurry containing a surfactant to the gas diffusion layer while controlling the film thickness, followed by heat treatment, and then impregnating the applied surface with an electrolyte. Fuel cell electrode. 3. The fuel cell electrode according to claim 1, wherein the fuel cell electrode is an electrode for a polymer electrolyte fuel cell. 4. A fuel cell electrode having a catalyst layer containing (A) a catalyst powder and an electrolyte or (B) a catalyst layer containing a catalyst powder, an electrolyte and a water repellent agent, which is carried on a gas diffusion layer. In doing so, a highly viscous slurry containing catalyst particles and a nonionic surfactant or a highly viscous slurry containing catalyst particles, a water repellent and a nonionic surfactant is applied to the gas diffusion layer while controlling the film thickness. After that, heat treatment is performed, and then the coated surface is impregnated with an electrolyte. 5. A fuel cell electrode comprising: (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 doing so, a high-viscosity slurry containing catalyst particles and a nonionic surfactant, or a high-viscosity slurry containing catalyst particles, a water repellent and a nonionic surfactant is used for one or more film thickness control blades. A method for producing an electrode for a fuel cell, which comprises applying a heat treatment to a gas diffusion layer while controlling the film thickness with a feeder provided with the above, heat treating, and then impregnating the coated surface with an electrolyte. 6. The method for producing a fuel cell electrode according to claim 4, wherein the method for producing a fuel cell electrode is a method for producing a polymer electrolyte fuel cell electrode. 7. The method for producing an electrode for a fuel cell according to claim 4, 5 or 6, wherein the gas diffusion layer is carbon paper or water repellent carbon paper. 8. The method for producing an electrode for a fuel cell according to claim 4, 5, 6 or 7, wherein the catalyst particles are carbon powder supporting platinum and the water repellent agent is a polytetrafluoroethylene polymer. . 9. A fuel cell electrode comprising: (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. An apparatus for controlling a film thickness of one or a plurality of high-viscosity slurries containing catalyst particles and a nonionic surfactant, or a high-viscosity slurry containing catalyst particles, a water repellent and a nonionic surfactant. An apparatus for producing an electrode for a fuel cell, characterized in that the coating is applied on the gas diffusion layer while controlling the film thickness by a feeder equipped with a blade, heat treatment is performed, and then the coated surface is impregnated with an electrolyte. . 10. The apparatus for producing a fuel cell electrode according to claim 9, wherein the apparatus for producing a fuel cell electrode is an apparatus for producing a polymer electrolyte fuel cell electrode. 11. The manufacturing apparatus of an electrode for a fuel cell according to claim 9, wherein the gas diffusion layer is carbon paper or water repellent carbon paper. 12. The apparatus for producing a fuel cell electrode according to claim 9, 10 or 11, wherein the catalyst particles are carbon powder supporting platinum, and the water repellent agent is a polytetrafluoroethylene-based polymer.