JP2002280004A - Method of manufacturing for electrode for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing for an electrode for a fuel cell reducing electric resistance. SOLUTION: A material obtained by mixing conductive base material fibers, flake graphite powder having large aspect ratio, and a binder is used. A molding process forming a sheet serving as the electrode for the fuel cell from the mixture material is contained. The molding process contains a process preparing a first liquid material containing conductive base material fibers, flake graphite powder having large aspect ratio, the binder, and a dispersing medium, and a paper making process forming the sheet serving as the electrode for the fuel cell by the paper making treatment of the first liquid material. By making a flake graphite particle 200 present between conductive base material fibers 100, contact area between base material fibers is considerably increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrode for a fuel cell comprising a conductive base fiber as a main component. The present invention can be used for an electrode of a solid polymer electrolyte type fuel cell.

[0002]

2. Description of the Related Art The main requirements for fuel cell electrodes include:
High conductivity is required. As prior art 1, Japanese Patent Application Laid-Open No. 7-130374 discloses a porosity of 80%.
Using commercially available carbon paper and a PTFE-based dispersion in which PTFE-based particles capable of functioning as a water-repellent material are dispersed,
There is disclosed a technique for manufacturing an electrode used in a solid polymer electrolyte type fuel cell, which includes a step of immersing a commercially available carbon paper in a PTFE-based dispersion and a step of baking the carbon paper thereafter.

[0003] As prior art 2, Japanese Patent Application Laid-Open No. 2000-2000
No. 136493 discloses a molded sheet that is formed into a sheet shape using conductive carbon fibers and a binder, and is then dried. The molded sheet is immersed in a PTFE dispersion, and then fired to reduce the PTFE particles. There is disclosed a technique for manufacturing an electrode used in a solid polymer electrolyte fuel cell in which a binder is fixed to a molded sheet and the binder is removed by oxidation at the same time.

[0004]

The electrodes manufactured by the above-mentioned prior art have a limit in improving the conductivity. The carbon paper used in the prior art 1 is
Since the carbon fiber bonded with the thermosetting resin is manufactured by hot pressing in an inert gas at a considerably high temperature of 1000 ° C. or more, the cost is high. Therefore, the fuel cell using the electrode manufactured in this way is expensive,
There were problems that hindered practical application.

In the molded sheet used in the prior art 2, the contact frequency between the conductive carbon fibers is not always sufficient.

The present invention has been made in view of the above circumstances, and has as its object to provide a method of manufacturing an electrode for a fuel cell which is advantageous for reducing electric resistance.

[0007]

The inventor has been diligently developing a method of manufacturing an electrode for a fuel cell. Then, using a material obtained by mixing a conductive base material fiber such as carbon fiber and a flaky graphite powder having a large aspect ratio with a binder, and forming the material into a sheet shape based on a sheet forming process, It was found that the formation of the fuel cell electrode was advantageous in improving the conductivity of the fuel cell electrode, and confirmed by a test for measuring electric resistance. Thus, the manufacturing method according to the present invention was completed.

Although the reason for improving the conductivity of the fuel cell electrode is not always clear, it is presumed as follows. When flaky graphite powder having a large aspect ratio is not added, conductive base fibers such as carbon fibers are entangled with each other in a state of point contact or near point contact. In such a state of point contact or close to point contact, the contact conductive area between conductive base fibers such as carbon fibers is small, and there is a limit in improving conductivity. However, if the two-dimensional flaky graphite powder having a large aspect ratio is added, conductive base fibers such as carbon fibers can form particles of the flaky two-dimensional graphite powder having a large aspect ratio. The frequency of contact through increases.

FIG. 3 shows a model of the contact form between conductive base fibers 100 such as carbon fibers.
The hatched area indicates the contact area between the conductive base fibers 100. As shown in FIG. 3A, even if the conductive base fibers 100 are entangled with each other, the contact area where the conductive base fibers 100 contact each other is small because the base fibers 100 are long and thin. . FIG. 3B shows a model of an ideal contact form between the conductive base fibers 100 in the case where flaky graphite powder particles are present. As shown in FIG. 3 (B), the conductive base fiber 1
If the particles 200 of the flaky graphite powder having a two-dimensional shape are present during the period of 00, the contact area between the conductive base fibers 100 is considerably increased. It is presumed that this improves the conductivity between the base fibers 100 having conductivity, and thus improves the conductivity and current collection of the fuel cell electrode. FIG. 3B shows an ideal form of conductive contact.

[0010] A method of manufacturing an electrode for a fuel cell according to the present invention is a sheet forming step of forming a sheet to be an electrode for a fuel cell from the material by using a material obtained by mixing a conductive base fiber and a binder. In the method for producing an electrode for a fuel cell, the material contains flaky graphite powder having a large aspect ratio.

The sheet manufactured by the manufacturing method according to the present invention includes, in addition to conductive base fibers such as carbon fibers,
It contains flaky graphite powder with a large aspect ratio. In such a sheet, the frequency of contact between conductive base fibers such as carbon fibers via flaky graphite powder particles having a large aspect ratio and a two-dimensional spread increases. This is presumed to increase the conductive contact point or conductive contact area between conductive base fibers such as carbon fibers. According to the present invention, at least one of the following forms can be adopted.

The conductive base fiber is preferably a carbon fiber in consideration of thermal stability and chemical stability. The conductive base fiber such as carbon fiber is preferably a short fiber in consideration of dispersibility in the first liquid material, but may be a long fiber. The length and diameter of the conductive base fiber such as carbon fiber can be appropriately selected, but in consideration of the base fiber of the electrode and the dispersibility in the first liquid, the length is 0.2-30 mm, especially 0.5-10 mm, diameter 1-60 μm, especially 3-30
μm can be adopted.

The graphite powder is in the form of a flake. A typical flake shape is, for example, a scale shape. If the aspect ratio of the flaky graphite powder is excessively small, conductive contact points between conductive base fibers such as carbon fibers,
The effect of increasing the conductive contact area is not sufficiently exhibited.
If the aspect ratio of the flaky graphite powder is excessively large, when the graphite powder is mixed with the conductive base fiber, the binder, and the graphite powder, the particles of the graphite powder are easily broken, and the particles of the graphite powder after mixing are mixed. Conversely, the aspect ratio may be reduced, the particle size of the graphite powder may be more difficult to control, the dispersibility in the first liquid material may be reduced, and the papermaking process may not be performed well. In consideration of such circumstances, cost, and the like, the aspect ratio of the particles of the flaky graphite powder can be set to 2 to 300. In particular, considering the papermaking process, ensuring conductivity, cost, and the like, and considering the case of papermaking process, etc., the aspect ratio of the flaky graphite powder particles is 2 to 250, especially 3 to 1.
00 is preferable, and 10 to 40 is also preferable. However, it is not limited to this. The aspect ratio means the projected diameter / thickness of the flaky graphite powder particles.

The average particle size of the flaky graphite powder particles can be appropriately selected, but can be 5 to 250 μm, particularly 10 to 100 μm, and 15 to 40 μm.
μm. However, it is not limited to this.

In the sheet forming step of the production method according to the present invention, the first liquid material containing conductive fiber base material such as carbon fiber, flaky graphite powder having a large aspect ratio, a binder, and a dispersion medium is used. And a paper making process of forming a sheet to be a fuel cell electrode by subjecting the first liquid material to a paper making process. Further, according to the papermaking process, productivity can be improved, which is advantageous for cost reduction, and can also contribute to thinning of the electrode thickness. In this case, the first liquid material includes conductive base fibers such as carbon fibers, flaky graphite powder having a large aspect ratio, a binder, and a dispersion medium. As the binder, an organic substance, for example, a fiber such as pulp can be used, and in some cases, a vegetable fiber such as cotton, an animal fiber such as wool, or the like can be used.
Water can be generally used as the dispersion medium, and in some cases, an organic solvent such as toluene, xylene, or cyclohexane may be used. The first liquid material may contain an organic dispersant or another organic binder in addition to fibers such as pulp.

As a typical paper making process, there is a process in which a solid material and a dispersion medium in the first liquid material are separated to form a paper-like sheet by collecting the solid materials. In separating the solid material and the dispersion medium in the first liquid material, the first liquid material is rinsed with a separating member such as a mesh member, and the solid material contained in the first liquid material is separated from the dispersion medium. And a form in which the solid in the first liquid is separated from the dispersion medium by vacuum suction or drying to collect the solids, thereby obtaining a paper-like thin sheet. You. Examples of the solid material in the first liquid material include a base fiber, a binder, and particles of flaky graphite powder.

According to the paper making process, it is advantageous to attach flaky graphite powder particles to conductive base fibers such as carbon fibers. During the papermaking process, the flaky graphite powder contained in the first liquid together with the conductive base fiber such as carbon fiber adheres to the conductive base fiber and the binder to form the first graphite powder. This is because it is separated from the liquid material.

It is preferable that the binder contained in the first liquid material is a binder that can be eliminated. An organic substance, for example, fiber such as pulp can be used as the eliminable binder, and in some cases, vegetable fiber such as cotton and animal fiber such as wool can be used. In the first liquid, the flaky graphite powder having a large aspect ratio is contained in an amount of 0.5 to 60 parts by weight when the conductive base fiber and the eliminable binder are 100 parts by weight. Can be employed, especially 1 to
50 parts by weight, 1 to 30 parts by weight can be employed.

In the sheet forming step according to the present invention, after the above-described paper making step, the second liquid material containing a water-repellent binder as a main component is brought into contact with the sheet after the paper making step to provide water repellency. Comprising an impregnating step of impregnating a void portion of the sheet with a binder having the following, and a heating step of heating the sheet after the impregnation step to fix the water-repellent binder and simultaneously eliminate the dissipable binder. Can be adopted. By the binder having water repellency, the holding properties of the conductive base fiber such as carbon fiber and the flaky graphite powder in the electrode are ensured. As described above, organic materials such as fibers such as pulp, vegetable fibers such as cotton, and animal fibers such as wool can be used as the eliminable binder. After the eliminable binder has disappeared, voids can be formed, so that the effect of contributing to the improvement of gas diffusibility during use of the fuel cell can be expected, and the impregnation of the water-repellent binder is ensured.

As a binder having water repellency, it is preferable to use a fluororesin type in consideration of securing water repellency, chemical stability and the like. As fluororesin,
Polytetrafluoroethylene (PTFE) can be employed, and in some cases, tetrafluoroethylene.
Ethylene copolymer (ETFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (P
FA), at least one of tetrafluoroethylene / hexafluoropropylene copolymer (FEP) and the like. In the impregnation step, a suspension dispersion in which the above-mentioned fluororesin particles are dispersed can be used as the second liquid. It is preferable that the above-mentioned second liquid material contains a fine powder conductive material such as carbon black. Thereby, the conductivity of the electrode can be further increased.

A catalyst layer may or may not be laminated on the electrode. The catalyst layer mainly contains a catalyst metal such as platinum.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described based on test examples. In the present embodiment, a paper making process is performed. As the conductive base fiber, short carbon fiber was used. The size of the carbon fiber was 13 μm in diameter and 3 mm in length. Exfoliated graphite powder with large aspect ratio from the above carbon fiber, water (dispersion medium) and pulp (dissipable binder)
And these were dispersed in water at the compounding ratios shown in Table 1. In this way, slurry-like first liquid materials for papermaking according to Examples 1 to 5 were formed. In this case, the total of the carbon fiber and the pulp was 100 parts by weight, and the flaky graphite powder having a large aspect ratio was changed to 2 to 30 parts by weight. The flaky graphite powder has an average particle size of 20 μm, an average thickness of 1 μm,
The one having an aspect ratio of 20 was used.

[0023]

[Table 1]

The first liquid in the form of slurry is subjected to a papermaking process, and solids (particles of carbon fiber, pulp, graphite powder) contained in the first liquid are separated by a separating member such as a mesh member. I let it. This gives a thickness of 0.3
mm molded sheet was produced. In the paper making process, the first liquid is flown on the upper surface of the mesh member arranged horizontally, and water (dispersion medium) contained in the first liquid is separated from the solid content.
The method was carried out by depositing solids on the upper surface of the mesh member.

The above molded sheet is sized to a predetermined size (16
(0 mm x 160 mm) to produce electrode sheet materials according to Examples 1 to 5.

Since the flaky graphite powder dispersed in the first liquid material has a very small diameter, it is inherently difficult to be trapped from the slurry-like first liquid material during papermaking. Having. However, according to this embodiment,
The flaky graphite powder adheres to carbon fibers, pulp, and the like during the papermaking process and is captured from the slurry-like first liquid. Incidentally, according to the test of the present inventors, the yield at which the flaky graphite powder contained in the first liquid was captured by the sheet material was as high as about 80 to 90%.

Further, carbon black (conductive substance) was wetted with a surfactant and diluted with ion-exchanged water to prepare an aqueous solution containing 20% by weight of carbon black. Further, a suspension dispersion of polytetrafluoroethylene (hereinafter also referred to as PTFE) particles (manufactured by Daikin Industries, Ltd.)
D-1, containing 60% by weight of PTFE particles) and the above aqueous solution to form a second liquid. In the second liquid, the weight ratio between the carbon black and the solid content of PTFE is 2%.
The mixture was mixed at 0:15.

Each of the electrode sheet materials according to Examples 1 to 5 was immersed in the second liquid. As a result, the voids of the electrode sheet material were impregnated with the second liquid PTFE. Then, the electrode sheet material is placed in the atmosphere for 10 minutes.
Dry at 0 ° C. for 20 minutes, then 380 in air
C. for 1 hour. As a result, the pulp contained in the electrode sheet material was oxidized and gasified to disappear and be removed, and PTFE was fixed to carbon fibers, thereby producing a sheet-like fuel cell electrode.

Therefore, the sheet-shaped fuel cell electrode contains carbon black and PTFE as a water-repellent material, in addition to carbon fiber and graphite powder having a large aspect ratio. The above-mentioned PTFE imparts water repellency to the fuel cell electrode, and also serves as a binder for retaining carbon fibers, graphite powder, and carbon black in place of the pulp that has been removed and removed.

The electrical resistance per unit area of the fuel cell electrode manufactured as described above was measured. That is, this electrode is sandwiched between a pair of gold-plated steel sheets, and 1.96M
The electric resistance (average value) in the thickness direction per unit area of the electrode was measured while applying a load of Pa. The measurement results of the electric resistance per unit area are shown in Table 2 and FIG.

According to the test results shown in Table 2 and FIG. 1, in order to reduce the electric resistance of the electrode, the amount of the flaky graphite powder having a large aspect ratio was determined by changing the amount of the carbon fiber and pulp in the first liquid. When the total is 100 parts by weight, 1 to 30 parts by weight is preferable. If the amount of the flaky graphite powder having a large aspect ratio is too large, the cost is likely to be increased, and the moldability may be reduced.

In both Comparative Example 2 and Example 3, 10 parts by weight of graphite was added to the first liquid material, but the aspect ratio was higher than that of Comparative Example 2 in which graphite powder having an aspect ratio of 1.5 was added. In Example 3 in which 20 graphite powders were blended, the electric resistance of the electrode was reduced.
This shows that the use of flaky graphite powder having a large aspect ratio is effective.

[0033]

[Table 2]

(Application) FIG. 2 shows a state in which an electrode manufactured according to the above-described manufacturing method is incorporated in a cell of a fuel cell.
Is shown schematically in FIG. Since FIG. 2 is a schematic diagram, it does not specify the magnitude relation of the thickness. The cells of this fuel cell are solid polymer electrolyte type fuel cells. As shown in FIG. 2, the fuel cell has a fuel electrode 2 sandwiching a solid polymer membrane type solid electrolyte membrane 10 (Nafion manufactured by DuPont, USA).
0 and an oxidizer electrode 30. A fuel cell is formed by stacking a large number of the above-described cells.

The fuel electrode 20 and the oxidizer electrode 30 are formed based on the electrodes manufactured by the above-described manufacturing method. A catalyst layer 22 having a catalyst metal is provided between the fuel electrode 20 and the solid electrolyte membrane 10 so as to face the solid electrolyte membrane 10. Oxidizer electrode 30 and solid electrolyte membrane 10
Also, a catalyst layer 32 having a catalyst metal is provided so as to face the solid electrolyte membrane 10. The catalyst layer 2
2 is stacked on the fuel electrode 20, and the catalyst layer 32 is
May be laminated. Alternatively, the catalyst layers 22, 32
May be laminated on the solid electrolyte membrane 10. Catalyst layer 2
When the catalyst layer 2 is laminated on the fuel electrode 20 and the catalyst layer 32 is laminated on the oxidant electrode 30, a catalyst paste in which carbon powder supporting a catalyst, water, an ion exchange solution, and isopropyl alcohol are mixed at a predetermined ratio is used. It can be formed by applying a predetermined thickness to one surface of the electrode sheet by a doctor blade method.

The fuel electrode 20 faces a passage forming member 26 which is also called a separator and forms a gas passage 25 through which a hydrogen-containing gas containing hydrogen as the negative electrode active material (or pure hydrogen gas) flows. The oxidant electrode 30 faces a passage forming member 36 which is also referred to as a separator and forms a gas passage 35 through which an oxygen-containing gas containing oxygen as a positive electrode active material (pure oxygen gas may flow). According to the above-described fuel cell, a hydrogen-containing gas (type: pure hydrogen, hydrogen utilization rate 80%) containing hydrogen is supplied to the gas passage 25, and an oxygen-containing gas (type: air, air utilization rate 25%) is supplied. Gas passage 35
When the test was performed by supplying the fuel cell, the power generation performance of the fuel cell was good.

According to the fuel cell, excessive drying of the solid electrolyte membrane 10 is not preferable. This is because the proton conductivity of the solid electrolyte membrane 10 decreases during use. For this reason, conventionally, the hydrogen-containing gas and the oxygen-containing gas supplied to the fuel cell are often humidified. In consideration of this, it is preferable that the gas permeability in the thickness direction of the fuel electrode 20 and the oxidant electrode 30 can be adjusted within a considerable range according to the use and type of the fuel cell. In this respect, the flaky graphite powder having a large aspect ratio and a large two-dimensional property can be expected to have a covering effect as compared with a normal graphite powder having an aspect ratio close to 1. Therefore, in the fuel electrode 20 and the oxidizer electrode 30 formed by the electrodes in which the flaky graphite powder having a large aspect ratio having a two-dimensional spread and a large two-dimensional property is blended with the carbon fiber, the fuel cell It is advantageous to adjust the gas permeability of the fuel electrode 20 and the oxidizer electrode 30 in the thickness direction according to the use and type of the fuel cell. Therefore, it is advantageous for adjusting the water content of the solid electrolyte membrane 10 and adjusting the proton conductivity of the solid electrolyte membrane 10. In particular, it is advantageous for suppressing excessive drying of the solid electrolyte membrane 10, improving the proton conductivity of the solid electrolyte membrane 10, and improving the output of the fuel cell.

Further, in the fuel electrode 20 and the oxidizer electrode 30 formed of the electrode in which the flaky graphite powder is blended with the carbon fiber, the fuel electrode 20 and the oxidizer electrode 30 are formed by the flaky graphite powder. Adjustment of gas diffusivity in the plane direction can also be expected.

According to the above embodiment, the fuel electrode 2
0 and the oxidizer electrode 30 are formed based on the common electrode manufactured by the above-described manufacturing method.
The physical properties and contents of the carbon fiber, the flaky graphite powder having a large aspect ratio, and the like in the electrode constituting 0 and the electrode constituting the oxidant electrode 30 may be changed as necessary.

(Others) According to the above-described embodiment, the second liquid material contains carbon black as a conductive material and PT.
Although the FE is mixed so as to have a weight ratio of 20:15 to the solid content, the FE is not limited to this and can be changed as needed. In the second liquid, carbon black and P
The weight ratio of TFE to the solid content is, for example, 20:
It can be adjusted in the range of (2 to 60). If the mixing ratio is smaller than 2, it becomes difficult to secure the strength of the sheet. If it is larger than 60, the electric resistance of the sheet will increase.

Further, according to the above-described embodiment, PTFE
And a second liquid containing carbon black as a main component is impregnated into the gaps of the electrode sheet material to form a PTF.
Although E and carbon black are held on the sheet at the same time, the invention is not limited to this, and they may be held individually. The present invention is not limited to the embodiment described above and shown in the drawings, but can be implemented with appropriate modifications without departing from the scope of the invention. The matters described in the embodiments can be described in the claims even if only a part.

(Supplementary Note) The following technical idea can be understood from the above description. (Supplementary note) A fuel characterized by comprising, as main components, conductive base fiber, flaky graphite powder having a large aspect ratio, and a binder (generally, a fluororesin) that binds these. Electrodes for batteries. The conductivity of the electrode is ensured. (Supplementary notes) Conductive base fiber, flaky graphite powder having a large aspect ratio, and a binder (eg, eliminable binder such as pulp,
A sheet for a fuel cell electrode containing (fluorine resin) as a main component. (Supplementary notes) A conductive base material comprising a conductive base fiber, a flaky graphite powder having a large aspect ratio, and a binder (generally, a fluororesin) that binds them. An electrode for a fuel cell, wherein material fibers are frequently in contact with each other via flaky graphite powder particles. The conductivity of the electrode is ensured. (Supplementary notes) The main components are a conductive base fiber, a flaky graphite powder having a large aspect ratio, and a binder (a eliminable binder such as pulp or a fluororesin) that binds these. A fuel cell electrode sheet, wherein the conductive base fibers are frequently in contact with each other via flaky graphite powder particles. (Supplementary note) A fuel electrode to which a hydrogen-containing gas is supplied, an oxidant electrode to which an oxygen-containing gas is supplied, and a solid polymer electrolyte membrane-type solid electrolyte membrane sandwiched between the fuel electrode and the oxidant electrode In a fuel cell having one or both of a fuel electrode and an oxidizer electrode, one or both of a fuel electrode and an oxidizer electrode are composed mainly of a conductive base fiber, a flaky graphite powder having a large aspect ratio, and a binder material that binds these. A fuel cell, characterized in that:

[0043]

As described above, since particles of a flaky graphite powder having a two-dimensional shape having a large aspect ratio are added to a fuel cell electrode, a conductive material such as carbon fiber is used. An increase in conductive contact points between the material fibers and an increase in conductive contact area can be expected. Therefore, it is advantageous in reducing the electric resistance of the fuel cell electrode, improving the current collecting performance, and improving the performance of the fuel cell.

Further, in the case where a sheet serving as an electrode is formed through a paper-making process of separating a solid contained in the first liquid material and a dispersion medium to obtain a paper-like sheet, the sheet-forming process may be carried out. In addition, the flaky graphite powder particles having a large aspect ratio contained in the first liquid material tend to easily adhere to conductive base fibers, binders, and the like. Therefore, the particles of the flaky graphite powder increase the conductive contact points between conductive base fibers such as carbon fibers,
This is more advantageous for increasing the conductive contact area.

[Brief description of the drawings]

FIG. 1 is a graph showing measured data of electric resistance.

FIG. 2 is a schematic diagram of a fuel cell.

FIG. 3 is a schematic diagram modeling a contact mode between conductive base fibers such as carbon fibers.

[Explanation of symbols]

In the figure, 10 is a solid electrolyte membrane, 20 is a fuel electrode, 30 is an oxidizer electrode, and 22 and 32 are catalyst layers.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Tomita 2-1-1 Asahi-machi, Kariya-shi, Aichi Prefecture Inside Aisin Seiki Co., Ltd. No. 1 Aisin Chemical Co., Ltd. (72) Inventor Kenji Sugiura 1141, Oinogahara, Iino, Oji, Fujioka-cho, Nishikamo-gun, Aichi Prefecture (72) Inventor Hikaru Okamoto 5-chome, Hachikencho, Kariya City, Aichi Prefecture No. 50 F-term in the IMRA Materials Development Laboratory (reference) 5H018 AA06 AS02 AS03 BB00 BB01 BB12 DD05 EE05 EE06 HH05 5H026 AA06 BB00 BB01 BB08 CC03 CX02 EE05 EE06 HH05

Claims (7)

[Claims] 1. A method for producing a fuel cell electrode, comprising a sheet forming step of forming a sheet to be a fuel cell electrode from the material by using a material obtained by mixing a conductive base fiber and a binder, The method for manufacturing an electrode for a fuel cell, wherein the material includes flaky graphite powder having a large aspect ratio. 2. The sheet forming step according to claim 1, wherein the first liquid material containing the conductive base fiber, the flaky graphite powder having a large aspect ratio, the binder and the dispersion medium is used. A method for manufacturing an electrode for a fuel cell, comprising: a preparing step; and a paper making step of forming a sheet to be an electrode for a fuel cell by subjecting the first liquid material to a paper making process. 3. The method for producing an electrode for a fuel cell according to claim 1, wherein the flaky graphite powder has an aspect ratio of 2 to 300. 4. The method for manufacturing a fuel cell electrode according to claim 1, wherein the flaky graphite powder has an average particle size of 10 to 250 μm. 5. The material according to claim 1, or the first liquid material according to claim 2, wherein the conductive base material fiber and the binder are 100 parts by weight in the first liquid material. When the flaky graphite powder is 0.5 to
A method for producing an electrode for a fuel cell, comprising 60 parts by weight. 6. The method for producing an electrode for a fuel cell according to claim 1, wherein the conductive base fiber is a carbon fiber. 7. The method according to claim 2, wherein the binder contained in the first liquid material is a binder that can be eliminated, and the sheet forming step is performed after the paper making step. An impregnating step of impregnating a void portion of the sheet with the water-repellent binder by contacting a second liquid material having a binder having a main component with the sheet after the papermaking step; and A heating step of heating a subsequent sheet to fix the water-repellent binder and simultaneously remove the eliminable binder.