WO2020027326A1 - Electrode for fuel cells, fuel cell and method for producing electrode for fuel cells - Google Patents

Abstract

A fuel cell (10) according to the present invention is provided with an air electrode (13), a fuel electrode (11) and an electrolyte solution (12) that is provided between the air electrode (13) and the fuel electrode (11). One example of the air electrode (13) comprises a conductive base material (15), an electrode catalyst and an oxygen permeable membrane (14), while having a structure wherein the conductive base material (15) and the oxygen permeable membrane (14) are directly bonded to each other by means of compression bonding. An oxygen permeable membrane-conductive base material mixture layer (145) is present between the conductive base material (15) and the oxygen permeable membrane (14).

Description

Fuel cell electrode, fuel cell, and method of manufacturing fuel cell electrode

The present invention relates to a fuel cell electrode, a fuel cell, and a method for manufacturing a fuel cell electrode.

Patent Literatures 1 and 2 disclose techniques related to electrodes of a microbial fuel cell (MFC).
Patent Document 1 (Japanese Patent Application Publication No. 2015-525692) describes a film to be used in an MFC. Specifically, the document discloses a membrane comprising a first layer of a polymer having high oxygen permeability and a second support layer made of a woven or non-woven material, wherein both layers are made. Is described using a membrane that is dot- or pattern-laminated together by using an adhesive, thereby providing an improved electrode configuration and, therefore, particularly for use in the field of MFCs. It is stated that an electron-gas / collection-transmission system can be provided.

Patent Document 2 (WO 2015/025917) discloses a microbial fuel cell electrode and a method of manufacturing the microbial fuel cell electrode, which have high conductivity, high corrosion resistance, and low cost. As a technique, used in a microbial fuel cell, comprising a conductive substrate, and a coating covering the surface of the conductive substrate, the coating is formed using a conductive carbon material and a resin, An electrode for a microbial fuel cell constituted by coating a conductive substrate with a coating, wherein the electrode for a microbial fuel cell having a specific resistivity is described. It is described that this electrode can be obtained by applying a conductive carbon material-containing liquid containing a resin and an organic solvent to a conductive base material and then evaporating and removing the organic solvent.

JP-T-2005-52569A WO 2015/025917

The present inventors have studied the air electrode of a fuel cell including an electrolyte such as a microbial fuel cell, and found that there is room for improvement in obtaining a high output with a simple structure. became.

Therefore, the present invention provides an electrode that can be used as an air electrode of a fuel cell including an electrolytic solution and that can obtain a high output with a simple structure.

According to the present invention, a fuel cell electrode, a fuel cell, and a method of manufacturing a fuel cell electrode described below are provided.
[1] An electrode used for a fuel cell including an air electrode, a fuel electrode, and an electrolytic solution disposed between the air electrode and the fuel electrode,
The air electrode includes a conductive substrate, an electrode catalyst and an oxygen permeable membrane,
(A) oxygen permeable membrane layer (AB) oxygen permeable membrane / conductive base material mixed layer (B) conductive base material layer (C) electrode catalyst layer
The fuel cell electrode, wherein the layer (A) is a thermoplastic resin layer, and the thickness of the layer (A) is 0.1 μm or more and 280 μm or less.
[2] An electrode used for a fuel cell including an air electrode, a fuel electrode, and an electrolytic solution disposed between the air electrode and the fuel electrode,
Including a conductive substrate, an electrode catalyst and an oxygen permeable membrane,
An electrode for a fuel cell, wherein the conductive substrate and the oxygen permeable membrane are in direct contact with each other and pressure-bonded.
[3] The fuel cell electrode according to [2], wherein the thickness of the oxygen permeable membrane is 0.1 μm or more and 1000 μm or less.
[4] The electrode for a fuel cell according to [1] or [2], wherein a material of the conductive substrate of the air electrode is a carbon material.
[5] The electrode for a fuel cell according to [2], wherein the oxygen-permeable membrane contains a thermoplastic resin.
[6] The method according to [1] or [5], wherein the oxygen-permeable film contains a thermoplastic resin having at least one of a melting point and a glass transition temperature determined by a differential scanning calorimeter in a range of 100 to 300 ° C. The electrode for a fuel cell according to the above.
[7] The material of the oxygen permeable membrane of the air electrode includes any one resin selected from the group consisting of poly-4-methyl-1-pentene, polybutene, polytetrafluoroethylene, and polydimethylsiloxane. The electrode for a fuel cell according to [1] or [5].
[8] The fuel cell electrode according to [1] or [5], wherein a material of the oxygen permeable membrane of the air electrode includes poly-4-methyl-1-pentene.
[9] The material of the electrode catalyst of the air electrode includes one or more metals selected from the group consisting of Ru, Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au. [1] Or the electrode for a fuel cell according to [2].
[10] The electrode for a fuel cell according to [9], wherein a material of the electrode catalyst of the air electrode includes Pt.
[11] The fuel cell electrode according to [10], wherein a layer of the electrode catalyst containing Pt is provided on a surface of the conductive substrate in the air electrode.
[12] The fuel cell electrode according to [1] or [2], wherein the fuel electrode includes a conductive substrate on which power-generating bacteria can be fixed.
[13] The fuel cell electrode according to [12], wherein the fuel electrode includes a conductive base material and a power-generating bacterium as an electrode catalyst.
[14] The electrode for a fuel cell according to [12], wherein the fuel electrode includes a conductive substrate made of a carbon material.
[15] The fuel cell electrode according to any one of [1], [2] and [12], wherein the fuel cell uses livestock excrement as fuel.
[16] A fuel cell comprising the fuel cell electrode according to any one of [1], [2], [12] and [15].
[17] The fuel cell according to [16], which does not include a proton conductive membrane as a constituent element.
[18] A method for producing an electrode used for an air electrode of a fuel cell including an air electrode, a fuel electrode, and an electrolytic solution disposed between the air electrode and the fuel electrode,
A step of bonding the conductive substrate and the oxygen-permeable film by pressing the conductive substrate and the oxygen-permeable film in direct contact with each other,
Immobilizing an electrode catalyst on the conductive substrate,
A method for producing an electrode for a fuel cell, comprising:
[19] The step of immobilizing the electrode catalyst on the conductive substrate includes a step of forming a layer of the electrode catalyst containing Pt on the surface of the conductive substrate by a sputtering method or an electrode reduction method. The method for producing an electrode for a fuel cell according to [18].
[20] The method for producing an electrode for a fuel cell according to [19], wherein the step of forming the electrode catalyst layer is a step of forming the layer containing Pt by the sputtering method.

According to the present invention, it is possible to provide an electrode which can be used as an air electrode of a fuel cell provided with an electrolytic solution and which can obtain a high output with a simple structure.

FIG. 1 is a cross-sectional view schematically illustrating a configuration example of a fuel cell according to an embodiment. FIG. 2 is a cross-sectional view schematically illustrating a configuration example of a fuel cell electrode in the embodiment. It is sectional drawing explaining the example of the manufacturing method of the electrode for fuel cells in embodiment. It is a figure showing an example of the section structure of an air electrode in an embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are denoted by common reference numerals, and description thereof will not be repeated. Also, the figure is a schematic view, and does not match the actual dimensional ratio. Further, “α to β” indicating a numerical range represents α or more and β or less unless otherwise specified.

FIG. 1 is a cross-sectional view schematically illustrating an example of the structure of the fuel cell according to the present embodiment. FIG. 1 shows a basic configuration of a fuel cell corresponding to the present embodiment.
In FIG. 1, a fuel cell 10 includes an air electrode 13, a fuel electrode 11, and an electrolyte 12 disposed between the air electrode 13 and the fuel electrode 11. The present embodiment is characterized by the structure of this electrode. That is, the electrode used for the air electrode 13 of the fuel cell 10 includes (B) the conductive substrate 15, the electrode catalyst ((C) the electrode catalyst layer 19 in FIGS. 2A and 2B), and ( (A) Including oxygen permeable film 14, (A) oxygen permeable film 14 and (B) conductive base material 15 are mixed as shown in FIG. 2 (b) (AB) oxygen permeable film / conductive base material mixture It also has a layer 145.
In the present embodiment, the thickness of the (AB) oxygen-permeable film / conductive substrate mixed layer 145 is the sum of the thicknesses of (B) the conductive substrate 15 and the (AB) oxygen-permeable film / conductive substrate mixed layer 145. Is preferably 0.1 to 60% with respect to 100%. A more preferred lower limit is 0.3% or more, more preferably 0.5% or more, still more preferably 0.7% or more, and even more preferably 0.8% or more. On the other hand, a more preferable upper limit is 50% or less, more preferably 45% or less, and further preferably 40% or less.
The air electrode 13 according to the present embodiment specifically has a laminated structure shown in FIG. In FIG. 2B, (A) an oxygen permeable film / conductive substrate mixed layer 145 in which (A) the material of the oxygen permeable film 14 and (B) the material of the conductive substrate 15 are mixed is provided. I have. In the laminated structure shown in FIG. 2B, for example, as shown in FIG. 2A, (A) the oxygen-permeable film 14, (B) the conductive base material 15, and (C) the electrode catalyst layer 19 It is obtained by laminating in order and pressing the (A) oxygen permeable film 14 and (B) the conductive substrate 15 by pressure. Details of the method for obtaining the air electrode 13 will be described later.
In the air electrode 13 of the present embodiment, it is preferable that the (AB) oxygen-permeable membrane / conductive base material mixed layer 145 has a dense structure and few voids. Specifically, the (AB) oxygen-permeable film / conductive base material mixed layer 145 can be observed with a scanning electron microscope photograph in which the cross section of the electrode is enlarged to a scale of several μm to 10 μm each in the vertical and horizontal directions. In order to prepare a sample for performing the cross-section observation, a material such as a resin for retaining the shape (sometimes referred to as an embedding material or an embedding resin) is preferably used for the electrode. It is preferable to cut the electrode after fixing it to the catalyst layer 19 by a method such as coating. In addition, it is possible to prepare a cross-sectional observation material by a known method.
FIG. 4 is a diagram illustrating an example of a cross-sectional structure of the air electrode 13. In FIG. 4, as a configuration example of the air electrode 13, a laminate of Pt / carbon paper / oxygen permeable membrane (TPX (registered trademark, the same applies hereinafter) membrane: manufactured by Mitsui Chemicals, Inc.) is created, and its cross section is scanned. The result of observation with an electron microscope (SEM) is shown. In the example of FIG. 4, in the mixed region of (B) the carbon fiber serving as the conductive base material 15 and (A) the TPX film serving as the oxygen permeable film 14, almost 100% of the carbon fibers are occupied by TPX. You can see that there is. That is, there is almost no void.
The (B) conductive base material 15 in the (AB) oxygen permeable film / conductive base material mixed layer 145 and the resin constituting the (A) oxygen permeable film 14 can be realized by a pressure bonding method as described later. It is preferable to be in such a mixed state.
The preferred mode of the (AB) oxygen-permeable film / conductive base material mixed layer 145 of this embodiment can be set as follows.
The configuration of the (AB) oxygen-permeable membrane / conductive base material mixed layer 145 of the present embodiment can be grasped by observing the cross section of the air electrode 13 of the present embodiment. Specifically, a cross section obtained by cutting the air electrode 13 of the present embodiment by an ordinary method is observed with an electron microscope. At the time of the cutting, the air electrode 13 can be reinforced in advance by a method such as attaching a known component such as a resin for retaining the shape or a carbon film to the surface of the air electrode 13 depending on the situation.
The (AB) oxygen permeable membrane / conductive base material mixed layer 145 of the present embodiment is a scanning electron microscope of the air electrode cross section of the present embodiment, in which the vertical and horizontal dimensions are respectively enlarged to a scale of several μm to 10 μm. In the photograph (using an S-4800 scanning electron microscope manufactured by Hitachi, Ltd.), for example, 10 or more, preferably 20 or more, and more preferably 30 or more (B) conductive base 15 components (for example, carbon fiber) which are adjacent to each other It is preferable to have a mode in which the (A) region in which the component of the oxygen permeable film 14 is present is preferably 80 area% or more, more preferably 90 area% or more, and still more preferably 95 area% or more of the gap. The adjacent gap is, for example, a gap between 10 or more carbon fibers in FIG. 4 (for example, a region of 3 * 4 in length * width). The embodiment of FIG. 4 can be described as follows. FIG. 4 shows a region in which TPX is present in almost all of the ten or more carbon fibers. Therefore, the embodiment of FIG. 4 is an embodiment in which the component of (A) the oxygen-permeable film 14 is present in (B) about 100% by area of the gap between the conductive substrates 15.
By satisfying the above conditions, it is considered that air (oxygen) taken in from the outside can be efficiently supplied to the electrode catalyst and a stable laminated structure can be maintained. For this reason, the present inventors believe that a fuel cell using the electrode of the present embodiment can achieve high output.
The (AB) oxygen-permeable film / conductive substrate mixed layer 145 has a form in which, for example, the (B) conductive substrate 15 and the (A) oxygen-permeable film 14 are in direct contact with each other and are pressed. The (AB) oxygen-permeable film / conductive base material mixed layer 145 obtained by such a pressure bonding step can be realized by a pressing method or a multilayer extrusion method as described later.
The fuel cell using the electrode including the air electrode according to the present embodiment exhibits high output. This is because (B) the conductive base material 15 and (A) the oxygen permeable film 14 are relatively thin (A) in comparison with the conventional bonding method or coating method using an adhesive. Since it is possible to form a state in which the contact is preferably made densely and firmly, it is considered that this is useful for realizing a high output efficiently and.

In FIG. 1, the fuel electrode 11 and the air electrode 13 are connected by an external circuit including an external resistor 17.
The fuel electrode 11 and the air electrode 13 are accommodated in a container 18, and the (A) oxygen permeable film 14 of the air electrode 13 forms a part of the outer wall of the container 18, and the (A) oxygen permeable film 14 (B) The air electrode 13 is in contact with the atmosphere 16 on the surface opposite to the contact surface with the conductive substrate 15.
For example, in the case of MFC, the electrolyte solution 12 contains an organic substance serving as a fuel, and is preferably an aqueous suspension of the fuel organic substance.
In the case of the MFC, specific examples of the aqueous suspension of the fuel organic matter include wastewater and domestic wastewater of livestock farmers including livestock excrement. Further, an additive for promoting power generation may be added to the electrolyte solution 12, and the additive is not limited, and examples thereof include iron compounds such as iron oxide and iron hydroxide. Of course, in a state other than the MFC, a liquid in which conventional hydrogen (including hydrogen obtained by reforming hydrocarbons) is dissolved or bubbled can be used in combination.
Further, the fuel cell 10 preferably does not include a proton conductive membrane as a component.

In the fuel cell 10 configured as described above, the fuel in the electrolyte 12, specifically, an organic substance is supplied to the fuel electrode 11, and the organic substance is decomposed to generate hydrogen ions and emit electrons.
The hydrogen ions generated at the fuel electrode 11 move in the electrolyte solution 12 and reach the air electrode 13. The electrons emitted from the fuel electrode 11 move to the air electrode 13 through an external circuit. The air electrode 13 is supplied with the atmosphere 16, that is, air (including oxygen). Then, at the air electrode 13, water is generated from hydrogen ions and oxygen in the air.
As a result, in the external circuit, electrons flow from the fuel electrode 11 to the air electrode 13, and power is extracted.

The fuel cell 10 is, for example, a microbial fuel cell. Hereinafter, the case where the fuel cell 10 is a microbial fuel cell will be described as an example.

The fuel cell 10 which is a microbial fuel cell uses, for example, livestock excrement and food waste as fuel. Further, examples of the electrolytic solution 12 include wastewater containing organic matter such as livestock excrement, sludge, and other biomass suspensions. Further, as the electrolytic solution 12, for example, after composting leaves or stems after harvesting that occurs on a farm, for example, a part or the whole thereof may be dissolved or suspended in water. Further, it is preferable that the electrolyte solution 12 contains a power-generating bacterium.
Then, at the fuel electrode 11, hydrogen ions and electrons are generated from organic matter by the action of microorganisms. Specifically, the fuel electrode 11 includes a conductive base material and a microorganism supported on the conductive base material, and preferably includes a conductive base material and a power generating bacterium as an electrode catalyst. Examples of the power-generating bacteria include bacteria having an extracellular electron transfer mechanism.
The microorganism may be one that oxidizes organic substances contained in the fuel to generate electrons, and may be one or more of them. Specific examples of microorganisms include those belonging to the genus Shewanella, the genus Geobacter, the genus Geothrix, and the genus Aeromonas. Desired microorganisms may be added and supported on the conductive substrate, or may be supported using microorganisms contained in wastewater. Although there is no limitation on the method of supporting the microorganisms, power generation is started using a conductive substrate that does not support microorganisms and an electrolyte solution containing the microorganisms as the fuel electrode 11, and the microorganisms are attached to the conductive substrate with the power generation. Method and the like.

From the viewpoint of efficiently causing a reaction at the fuel electrode 11, the conductive base material of the fuel electrode 11 is preferably made of a conductive material to which power-generating bacteria can be fixed.
Specific examples of the conductive material include carbon and a conductive metal.
In addition, from the viewpoint of having a shape capable of supporting the power-generating bacteria and allowing the fuel to move in the conductive base material, examples of the conductive base material include felts, woven fabrics, nonwoven fabrics, nets, sintered bodies, foams, and the like. Porous substrate. From the same viewpoint, it is preferable that the fuel electrode 11 includes a conductive substrate made of a carbon material such as carbon cloth, carbon paper, carbon felt, or a metal material such as stainless steel, and more preferably a carbon material. Further, the conductive substrate of the fuel electrode 11 may be surface-treated.

When the fuel electrode 11 has a sheet shape, the thickness of the fuel electrode 11 is preferably 0.1 mm or more, and more preferably 1 mm or more, from the viewpoint of stably supporting the power-generating bacteria. Further, from the viewpoint of reducing the size of the fuel electrode 11, the thickness of the fuel electrode 11 is preferably 20 mm or less, more preferably 10 mm or less.
Here, the thickness of the fuel electrode 11 may be the thickness of the conductive base material of the fuel electrode 11.

Next, the air electrode 13 will be further described.
In the present embodiment, the air electrode 13 is preferably composed of (A) an oxygen-permeable film 14, (AB) an oxygen-permeable film / conductive substrate mixed layer 145, (B) a conductive substrate 15, and (C) an electrode catalyst layer. 19 has a laminated structure located in this order. Preferably, the thickness of the (AB) oxygen-permeable membrane / conductive base material mixed layer 145 is in a specific range. As described above, in the (AB) oxygen-permeable film / conductive base material mixed layer 145, it is preferable that (A) the material (resin) of the oxygen-permeable film 14 and (B) the conductive base material 15 exist densely. .
In the air electrode 13, as described above, it is a preferable embodiment that (B) the conductive base material 15 and (A) the oxygen-permeable film 14 are in direct contact with each other and are pressed. More specifically, in a preferred embodiment, the (B) conductive base material 15 and the (A) oxygen permeable film 14 are pressure-bonded without using an adhesive. The air electrode 13 is preferably provided between the (B) conductive base material 15 and the (A) oxygen permeable film 14, the oxygen-permeable film / conductive base material mixed layer 145, the conductive base material 15, No layer (intervening layer) other than the oxygen permeable film 14 is provided.

The (A) oxygen permeable membrane 14 of the present embodiment preferably contains a thermoplastic resin, and is more preferably a thermoplastic resin membrane. (A) The oxygen permeable film 14 is preferably made of a material having excellent oxygen permeability and capable of suppressing leakage of the electrolyte solution 12 to the atmosphere 16. As described later, it is preferable that (A) the oxygen permeable membrane 14 does not allow the electrolyte 12 to pass through. In this regard, the material of the (A) oxygen permeable film 14 is, for example, a resin having oxygen permeability. Preferably, (A) the oxygen-permeable membrane 14 has at least one of a melting point and a glass transition temperature determined by a differential scanning calorimeter in the range of 100 to 300 ° C. Further, the resin having oxygen permeability is preferably a thermoplastic resin. However, even if the resin has low melt fluidity, it can be employed as long as it can be applied to, for example, press molding described below.
A preferred lower limit of the above-mentioned melting point is 110 ° C. or more, more preferably 120 ° C. or more. On the other hand, the upper limit is 290 ° C or less, more preferably 280 ° C or less, and further preferably 270 ° C or less.
The lower limit of the above-mentioned glass transition temperature is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. On the other hand, the upper limit is 290 ° C or less, more preferably 280 ° C or less, and further preferably 270 ° C or less.
The upper limit of the softening temperature of the resin having oxygen permeability is preferably 290 ° C. or lower, more preferably 280 ° C. or lower, and further preferably 270 ° C. or lower. Further, the material (resin) of the (A) oxygen permeable film 14 used in the present embodiment is preferably insoluble in the electrolytic solution. For example, when the electrolyte is aqueous, it is preferably a water-insoluble resin.
As the resin forming the oxygen permeable film of the present embodiment, a known thermoplastic oxygen permeable resin can be used without limitation. The preferred oxygen permeability of the oxygen permeable resin at 23 ° C. is 1.0 * 10 ⁻¹⁵ mol / m / (m ² · s · Pa) or more.
Specific examples of the oxygen-permeable resin include polyolefins such as poly-4-methyl-1-pentene and polybutene; fluorocarbon resins such as polytetrafluoroethylene; and silicones such as polydimethylsiloxane. Here, for example, the oxygen permeability of TPX (registered trademark) (trade name MX002) manufactured by Mitsui Chemicals, Inc., which is a commercial product of poly-4-methyl-1-pentene, is 9.40 * 10 according to the company's product brochure. ⁻¹⁵ mol / m / (m ² · s · Pa)
(A) The material of the oxygen permeable membrane 14 preferably contains any one resin selected from the group consisting of poly-4-methyl-1-pentene, polybutene, polytetrafluoroethylene, and polydimethylsiloxane, and more preferably Including 4-methyl-1-pentene.

(A) The thickness of the oxygen-permeable film 14 is preferably 0.1 μm or more, more preferably 1 μm or more, and still more preferably 10 μm or more, from the viewpoint of suppressing leakage of the electrolyte solution 12.
Further, from the viewpoint of improving the oxygen permeability, it is preferable that the thickness of the (A) oxygen permeable film 14 be small. In the present embodiment, the thickness of the (A) oxygen permeable film 14 is preferably 280 μm or less. (A) The thickness of the oxygen permeable film 14 is more preferably 250 μm or less, further preferably 200 μm or less, still more preferably 100 μm or less, and particularly preferably 50 μm or less. (A) The thickness of the oxygen permeable film 14 is particularly preferably 40 μm or less.
As described above, it is required as a preferable characteristic that the electrolyte solution 12 does not pass through the (A) oxygen permeable film 14. This is a performance that has a trade-off relationship with thinning.
Conventionally, in a film obtained by using a coating method of a generally used technique, pinholes and the like may be generated due to the possibility of simultaneous shrinkage during drying of a varnish forming solvent. Therefore, it is necessary to increase the film thickness to some extent. Further, depending on the shape of the conductive substrate 15 at the micro level (B), it is necessary to lower the concentration of the varnish so as to make it easy to penetrate the surface of the conductive substrate 15 (B). In this case, the probability of generation of pinholes due to evaporation of the solvent may increase.
On the other hand, since the (A) oxygen permeable film 14 of the present embodiment is specifically a thermoplastic resin film, it is possible to prepare a thin film in advance. By compressing or fusing this with (B) the conductive base material 15, a laminate (air electrode) which does not cause leakage of the electrolyte solution 12 even when it is thin can be obtained. Further, a method such as pressure bonding forms the (AB) oxygen-permeable film / conductive base material mixed layer 145 in a mode in which (A) the material of the oxygen-permeable film 14 and (B) the conductive base material 15 are densely present. It is also considered suitable above.
For these reasons, the mode in which the thermoplastic resin film is (A) the oxygen permeable film 14 is advantageous as the material of the air electrode 13 of the fuel cell of the present embodiment.
Such an (A) oxygen permeable membrane 14 may be used in combination with a support material such as an outer frame for the purpose of imparting strength as required.
On the other hand, in an aspect requiring strength or the like, (A) an aspect in which the oxygen-permeable film 14 is thick may be required. With a conventional coating method, it may be difficult to remove a solvent necessary for preparing a varnish in order to obtain a film having a thickness of only a certain degree or more. Depending on the type of the solvent, there is a concern that the performance of the electrolytic solution may be adversely affected. For this reason, a thickening step may be required in which the coating step is performed a plurality of times. This method requires a lot of man-hours and time, which may make quality control difficult.
In the embodiment in which the thermoplastic resin film of the present embodiment is used as the (A) oxygen permeable film 14, it is easy to manufacture an air electrode having a thick (A) oxygen permeable film 14 when using a compression bonding method. It would be obvious.
In such a case, the thickness of the (A) oxygen permeable membrane 14 is, for example, 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less, further preferably 100 μm or less, and still more preferably Is 50 μm or less.
On the other hand, as described above, the preferable lower limit of the thickness is preferably 0.1 μm or more, and more preferably 1 μm or more.

(B) Examples of the material of the conductive substrate 15 include those described above as the material of the conductive substrate of the fuel electrode 11.
(B) The conductive base material 15 may be formed of the same material as the conductive base material of the fuel electrode 11, or may be formed of a different material.
(B) The conductive substrate 15 is preferably made of a material having excellent oxygen permeability and water permeability, and is preferably made of a carbon material such as carbon cloth, carbon paper, and carbon felt. .

When (B) the conductive substrate 15 is in the form of a sheet, the thickness of the (B) conductive substrate 15 is preferably 10 μm or more, and more preferably 100 μm, from the viewpoint of stably supporting the electrode catalyst. That is all. Further, from the viewpoint of miniaturization of the air electrode 13, (B) the thickness of the conductive substrate 15 is preferably 5 mm or less, more preferably 1 mm or less.

In the air electrode 13, the electrode catalyst is supported on, for example, (B) the conductive base material 15. The electrode catalyst is preferably provided as (C) the electrode catalyst layer 19.
FIG. 2A and FIG. 2B are cross-sectional views illustrating a configuration example of an electrode used as the air electrode 13. As shown in FIGS. 2A and 2B, the air electrode 13 has (C) an electrode catalyst layer 19. The (C) electrode catalyst layer 19 is preferably provided on the surface of the (B) conductive substrate 15, that is, on the back surface of the bonding surface with the (A) oxygen permeable film 14, and the electrode catalyst is disposed in a layered manner. It becomes.
The (C) electrode catalyst layer 19 may be formed on the entire back surface of the conductive substrate 15 (B) or may be formed on a part thereof. Preferably, it is formed on the entire back surface. The (C) electrode catalyst layer 19 may be a layer formed from a sheet-like or thin-film catalyst, or may be a layer formed from a particulate catalyst. Even if the particulate catalysts are not in contact with each other, they need only form a layer as a whole. In the formation of the layer, a known technique such as, for example, using a binder resin in combination can be adopted.
(C) The thickness of the electrode catalyst layer 19 is preferably small from the viewpoint of increasing the specific surface area at the air electrode 13 and increasing the reaction efficiency. Preferably it is 1 nm or more, more preferably 10 nm or more. On the other hand, a preferred upper limit is 1000 nm or less, more preferably 500 nm or less, and further preferably 100 nm or less. Further, from the same viewpoint, the amount of the catalyst substance per unit electrode surface area is preferably 0.01 to 10 μmol / cm ² , and more preferably 0.1 to 5 μmol / cm ² .

(C) As a specific example of the electrode catalyst used for the electrode catalyst layer 19, a metal catalyst can be given. Further, as a material of the electrode catalyst, from the viewpoint of promoting a catalytic reaction at the air electrode 13, for example, one or more selected from the group consisting of Ru, Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au , Preferably containing Ru, Rh, Pd, Pt or Ag, and more preferably containing Pt. At this time, from the viewpoint of obtaining a high output with a small amount of catalyst, it is more preferable that the (C) electrode catalyst layer 19 containing Pt is provided on the surface of the (B) conductive base material 15. Further, (C) the electrode catalyst layer 19 is preferably in the form of a thin film, and more preferably, a sputtered layer of an electrode catalyst containing Pt is provided.

(4) When the overall shape of the air electrode 13 is a sheet, the thickness of the air electrode 13 is preferably 20 μm or more, and more preferably 100 μm or more, from the viewpoint of maintaining strength. In addition, from the viewpoint of miniaturization of the air electrode 13, the thickness of the air electrode 13 is preferably 7 mm or less, more preferably 5 mm or less, further preferably 2 mm or less, and still more preferably 1 mm or less.

Next, a method for manufacturing a fuel cell electrode used as the air electrode 13 will be described.
In the present embodiment, the electrode used as the air electrode 13 is, for example, (Step 1) by (C) pressure bonding in a state where the (B) conductive base material 15 and (A) the oxygen permeable film 14 are in direct contact with each other to obtain (B) The method includes a step of adhering the base material 15 to the (A) oxygen permeable membrane 14, and a step of (Step 2) and (B) fixing the electrode catalyst to the conductive base material 15.
The order of Step 1 and Step 2 is not limited, but from the viewpoint of stably fixing the electrode catalyst to (B) the conductive base material 15, Step 2 is preferably performed after Step 1.
As a method for the pressure bonding, a known molding method capable of realizing the pressure bonding state such as press molding, (co) extrusion molding, stamping molding, air pressure molding, and vacuum molding can be used without limitation. Among them, press molding (melt press molding or solid-phase press molding) is preferred from the viewpoint of the wide application range of resin, and (co) extrusion molding is a preferred example from the viewpoint of high productivity. Hereinafter, press molding will be described as an example.

FIG. 3A and FIG. 3B are cross-sectional views illustrating an example of Step 1.
Specifically, as shown in FIG. 3A, first, (A) the oxygen-permeable film 14 and (B) the conductive base material 15 between the heating plate 21a and the heating plate 21b which are arranged to face each other. Are placed directly on top of each other. Then, the (A) oxygen permeable film 14 and (B) the conductive base material 15 are sandwiched between the heating plates 21a and 21b and integrated by thermocompression bonding, whereby (A) the oxygen permeable film 14 and (B) B) A laminate of the conductive substrate 15 is obtained. Alternatively, (A) extrusion lamination processing in which the oxygen permeable membrane 14 is discharged from the extruder and (B) is pressed against the conductive substrate 15 may be used.
There are no restrictions on the conditions for thermocompression bonding. The temperature at the time of press bonding is preferably in the range of 10 to 80 ° C. lower than the melting point of the raw material resin of the oxygen permeable membrane (A), more preferably 10 to 60 ° C. lower. In particular, when (A) poly-4-methyl-1-pentene is thermocompression-bonded as a raw material resin for the oxygen permeable membrane 14, the temperature is preferably from 140 to 210 ° C., more preferably from 160 to 210 ° C., and more preferably 170 ° C. More preferred is a temperature of ℃ 200 ° C. The pressure during crimping is preferably from 0.1 to 10 MPa, more preferably from 0.5 to 5 MPa, even more preferably from 0.5 to 2 MPa.
On the other hand, there is a method in which a resin is melted at a temperature equal to or higher than a melting point or a glass transition temperature and brought into contact with a conductive base material, and then cooled and pressed. In this case, the resin is melted at a temperature higher by 10 to 50 ° C. than the melting point or the glass transition temperature, and the resin is melted and flowed. And a method of cooling at a temperature lower by at least 10 ° C. than the glass transition temperature. The pressure at this time can be lower than the above-mentioned pressure.
When the (B) conductive base material 15 and the (A) oxygen permeable film 14 are laminated by (co) extrusion molding, the resin temperature is equal to or higher than the melting point or the glass transition temperature in the extrusion stage. B) The resin temperature at the stage of bringing the conductive substrate 15 into contact with the (A) oxygen permeable film 14 is preferably in a range of 10 to 80 ° C. lower than the melting point or glass transition temperature described above, and is preferably 10 to 60 ° C. lower. Temperatures in the range are more preferred. Then, it is preferable that the (B) conductive base material 15 and the (A) oxygen permeable film 14 be pressure-bonded using a double roll or the like.

Step 2 includes, for example, (B) a step of forming (C) an electrode catalyst layer 19 containing Pt on the surface of the conductive substrate 15 by a sputtering method, an electrode reduction method, or the like, preferably by a sputtering method. This is a step of forming the (C) electrode catalyst layer 19 containing Pt.
The conditions for the sputtering are not limited, and the conditions such as the temperature and the time may be set as long as the sputtering is possible and the material (base material) does not deteriorate.

Further, as another method of Step 2, a coating solution containing catalyst-supporting particles obtained by supporting an electrode catalyst on carbon particles and a polymer electrolyte is prepared, and this is applied to (B) a conductive substrate 15. And (B) fixing the electrode catalyst to the conductive substrate 15 by drying.

Thus, an electrode used as the air electrode 13 is obtained.
Then, for example, the fuel electrode 11 and the air electrode 13 carrying microorganisms (such as power-generating bacteria) are arranged at predetermined positions of a container 18 and connected via an external resistor 17 to supply the electrolytic solution 12 into the container 18. By doing so, the fuel cell 10 can be obtained.

(Fuel cell)
In the fuel cell 10 obtained according to the present embodiment, the air electrode 13 includes (A) an oxygen-permeable film 14 and (B) a conductive base material 15 and a specific requirement located therebetween (AB) an oxygen-permeable film. -It has a structure having the conductive base material mixed layer 145. The air electrode 13 of the fuel cell 10 preferably has a form in which (A) the oxygen-permeable film 14 and (B) the conductive base material 15 are in direct contact with each other and crimped. Therefore, a high output can be obtained with a simple structure.
As described above, the fuel cell 10 of the present embodiment has a specific electrode structure, and thus can be used in a temperature environment of, for example, −50 ° C. or more and 300 ° C. or less including room temperature. The fuel cell 10 of the present embodiment can be suitably used as a power source for applications that operate in such a temperature range. For example, there is a possibility that the power supply can be used as a power supply in a mobility field such as a vehicle in addition to a general fixed-type power supply.
Hereinafter, a preferred utilization mode of the fuel cell of the present embodiment will be exemplified.
The fuel cell according to the present embodiment can generate power if there is a fuel substance containing hydrogen, and thus does not require the construction of a large-scale power generation facility or a transmission line. For this reason, it is considered to be suitable as an (auxiliary) power source for (large-scale) farms and (large-scale) ranches, which are often provided in suburbs or wilderness. In particular, when the form of MFC is adopted, the following utilization methods can be exemplified.
In a ranch, it can be suitably used as an electric light, a milking machine, a power source of a feed delivery system, a power source for daily life, and the like, and can be used at any time of the day or night. Livestock excrement can be used as MFC fuel, so that part or all of the fuel can be obtained from livestock.
On a farm, it can be used as a power source of a water or nutrient solution, a circulation system, or a (auxiliary) power source such as a harvesting device or an electric light. Further, after a non-edible portion (leaves, stems, etc.) generated after harvesting a plant, for example, is composted, part or all of the compost can be used as fuel for a fuel cell. Further, when the farm and the ranch are operated in cooperation, the non-edible portion of the plant may be given to livestock and the excrement thereof may be used as fuel for the fuel cell. As described above, it is considered that there is a possibility that a livestock system, a plant cultivation system, and a composite system thereof with high energy efficiency as a whole can be constructed.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than the above can be adopted.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

First, an example of manufacturing an air electrode and a fuel electrode is shown below.

(Catalyst 1)
A carbon cloth (HCB1071, manufactured by AvCarb, thickness 350 μm) was used as a conductive base material, and a poly-4-methyl-1-pentene (TPX, MX002O, manufactured by Mitsui Chemicals, Inc.) film (thickness 27 μm) was used as an oxygen permeable membrane. One by one sheets were stacked and pressed by a hot press (180 ° C., 3 MPa) to obtain a pressure-bonded poly-4-methyl-1-pentene / carbon cloth film.
The obtained pressure-bonded film is cut into a length of 130 mm and a width of 60 mm, and 1.8 mL of distilled water and Pt / C (Pt 37.5 wt%, Tanaka Kikinzoku Co., Ltd.) are added to 1.2 mL of a 5 wt% Nafion Perfluorinated resin solution (manufactured by SIGMA Aldrich). A suspension containing 105 mg of TEC10E40E (manufactured by TEC10E40E) was applied to the surface on the carbon cloth side, and was adhered to 2.56 μmol / cm ² . After drying at room temperature for 12 hours, a conducting wire was connected to produce an air electrode a.
The cross section of the air electrode a, reinforced with a carbon film and then cut, was observed with a scanning electron microscope (S-4800, manufactured by Hitachi, Ltd.), and a layer (TPX) in which the conductive base material and the TPX resin were densely mixed was observed. Is 100%).

(Example 2 of preparation of air electrode)
Using the carbon cloth / poly-4-methyl-1-pentene pressure-bonded film of 130 mm long × 60 mm wide obtained in the air electrode preparation example 1, Pt was adjusted to 0.26 μmol / cm ² by sputtering on the surface on the carbon cloth side. Attached in layers. Thereafter, the air electrode b was produced by connecting a conducting wire.
A layer in which the conductive base material and the TPX resin are densely mixed (a gap occupation ratio of TPX: 100%) is confirmed by observation with a scanning electron microscope in the same manner as in the preparation example 1 of the air electrode b. .

(Example 3 of preparation of air electrode)
An air electrode c was produced in the same manner as in the air electrode production example 2, except that the sputtering conditions were adjusted so that Pt was attached to be 0.03 μmol / cm ² .
Observation with a scanning electron microscope in the same manner as in the preparation of the air electrode c of the air electrode c confirms a layer in which the conductive base material and the TPX resin are densely mixed (the gap occupancy of TPX: 100%). .

(Example 4 of preparation of air electrode)
An air electrode d was produced according to Air electrode production example 1 except that carbon paper (P50, manufactured by AvCarb, thickness 170 μm) was used instead of carbon cloth as the conductive base material.
Observation with a scanning electron microscope in the same manner as in the air electrode preparation example 1 for the air electrode d confirms a layer in which the conductive base material and the TPX resin are densely mixed (the gap occupancy of TPX: 100%). .

(Example 5 of making air electrode)
An air electrode e was manufactured according to Air electrode manufacturing example 2, except that carbon paper (P50, manufactured by AvCarb, thickness 170 μm) was used instead of carbon cloth as the conductive base material.
Observation with a scanning electron microscope in the same manner as in the preparation example 1 of the air electrode e of the air electrode e confirmed a layer in which the conductive base material and the TPX resin were densely mixed (the gap occupancy of TPX: 100%). (See FIG. 4 above).

(Example 6 of producing air electrode)
An air electrode f was manufactured in accordance with the air electrode manufacturing example 5 except that Pt was attached to be 0.03 μmol / cm ² .
Observation with a scanning electron microscope in the same manner as in the air electrode preparation example 1 of the air electrode f confirms a layer in which the conductive base material and the TPX resin are densely mixed (the gap occupancy of TPX: 100%). .

(Example 7 of producing air electrode)
Using carbon cloth (HCB1071, manufactured by AvCarb, thickness of 350 μm) as a conductive substrate, carbon black (Valcan XC-72, manufactured by SIGMA Aldrich) in a 60% aqueous suspension of polytetrafluoroethylene (PTFE). The suspension to which Cabot Co. was added was applied as a varnish on one side to prepare a carbon cloth / polytetrafluoroethylene coated film coated with polytetrafluoroethylene as an oxygen permeable membrane.
The obtained coating film was cut into a length of 130 mm and a width of 60 mm, and Pt / C was applied to the surface of the carbon cloth side according to the air electrode preparation example 1, and was adhered so that Pt became 2.56 μmol / cm ² . After drying at room temperature for 12 hours, a conducting wire was connected to produce an air electrode j. The thickness of the oxygen permeable membrane was 300 μm.

(Example 8 of preparation of air electrode)
An air electrode k was produced in the same manner as in the air electrode production example 7, except that Pt / C was adhered so that Pt became 0.26 μmol / cm ² . The thickness of the oxygen permeable membrane was 300 μm.

(Example 9 of producing air electrode)
An air electrode 1 was prepared according to Air electrode preparation example 7, except that carbon paper (P50, manufactured by AvCarb, thickness 170 μm) was used instead of carbon cloth as the conductive substrate. The thickness of the oxygen permeable membrane was 300 μm.

(Example 10 of making air electrode)
A carbon cloth (HCB1071, manufactured by AvCarb, thickness of 350 μm) as a conductive base material was cut into a length of 130 mm × width of 60 mm, and Pt was applied to only one side by sputtering to form a layer of 0.26 μmol / cm ² . The conductor was connected. A film of poly 4-methyl-1-pentene having a length of 130 mm, a width of 60 mm and a thickness of 27 μm as an oxygen permeable film is applied to the entire surface of the carbon cloth on which Pt is not adhered by applying an epoxy adhesive to the entire surface. Thus, an air electrode m was prepared.

(Fuel electrode preparation example 1)
Carbon felt (manufactured by Sogo Carbon Co., Ltd.) was used as the conductive substrate, and this was cut into a length of 130 mm and a width of 60 mm to obtain a fuel electrode a.

(Examples 1 to 6, Comparative Examples 1 to 4)
A fuel cell 10 having the configuration shown in FIG. 1 was manufactured using the air electrode and the fuel electrode manufactured as described above, and the output was measured. Table 1 shows the configuration of the electrodes and the measurement results of the output used in each example. In each of the fuel cells, no leakage of the electrolyte from the air electrode was observed.

(Example 1)
Cow dung was suspended in distilled water, and an electrolytic solution was prepared so that the solid content in the suspension was 20 g / L, and 1.0 L was used as an electrolytic solution for power generation.
The air electrode a is installed such that the surface on the carbon cloth side to which Pt is attached is in contact with the electrolyte, and the surface on the oxygen permeable membrane side is in contact with the air, and the fuel electrode a is immersed in the electrolyte. Then, the fuel cell having the configuration shown in FIG. 1 was manufactured. The power generation test was started by connecting the air electrode a and the fuel electrode a through an external resistance of 150Ω, and the power-generating bacteria contained in the electrolyte were attached to the fuel electrode a during power generation. 0.39 mW was recorded as the maximum output value after attaching the power-generating bacteria.

(Example 2)
A power generation test was performed in the same manner as in Example 1 except that the air electrode b was used instead of the air electrode a, and a maximum output value of 0.48 mW was recorded.

(Example 3)
A power generation test was performed according to Example 1 except that the air electrode c was used instead of the air electrode a, and 0.39 mW was recorded as the maximum output value.

(Example 4)
A power generation test was performed in the same manner as in Example 1 except that the air electrode d was used instead of the air electrode a, and 0.83 mW was recorded as the maximum output value.

(Example 5)
A power generation test was performed in the same manner as in Example 1 except that the air electrode e was used instead of the air electrode a, and 0.80 mW was recorded as the maximum output value.

(Example 6)
A power generation test was performed according to Example 1, except that the air electrode f was used instead of the air electrode a, and 0.60 mW was recorded as the maximum output value.

(Comparative Example 1)
A power generation test was performed according to Example 1 except that the air electrode a was used instead of the air electrode a, and 0.30 mW was recorded as the maximum output value.

(Comparative Example 2)
A power generation test was performed according to Example 1 except that the air electrode k was used instead of the air electrode a, and 0.27 mW was recorded as the maximum output value.

(Comparative Example 3)
A power generation test was performed in the same manner as in Example 1 except that the air electrode 1 was used instead of the air electrode a, and a maximum output value of 0.30 mW was recorded.

(Comparative Example 4)
A power generation test was performed according to Example 1 except that the air electrode m was used instead of the air electrode a, and 0.05 mW was recorded as the maximum output value.

From the above results, it is possible to obtain relatively high output power by using the fuel cell including the air electrode having the specific configuration according to the present embodiment. This is thought to be the result of oxygen in the air efficiently reacting with hydrogen ions in the air electrode because the oxygen-permeable film is relatively thin and forms a suitable mixed layer with the conductive substrate. Can be

Hereinafter, examples of the reference embodiment will be additionally described.
1. An air electrode, a fuel electrode, and an electrode used for the air electrode of a fuel cell including an electrolyte disposed between the air electrode and the fuel electrode,
Including a conductive substrate, an electrode catalyst and an oxygen permeable membrane,
An electrode for a fuel cell, wherein the conductive substrate and the oxygen permeable membrane are in direct contact with each other and pressure-bonded.
2. The thickness of the oxygen permeable film is 0.1 μm or more and 1000 μm or less; 3. The electrode for a fuel cell according to item 2.
3. The fuel electrode includes a conductive substrate on which power-generating bacteria can be established. Or 2. 3. The electrode for a fuel cell according to item 2.
4. The fuel electrode includes a conductive base material and a power generation bacterium as an electrode catalyst. ~ 3. The fuel cell electrode according to claim 1.
5. The material of the conductive substrate of the air electrode is a carbon material. ~ 4. The fuel cell electrode according to claim 1.
6. The fuel electrode includes a conductive base made of a carbon material. ~ 5. The fuel cell electrode according to claim 1.
7. 1. The material of the oxygen permeable membrane of the air electrode includes any one resin selected from the group consisting of poly-4-methyl-1-pentene, polybutene, polytetrafluoroethylene, and polydimethylsiloxane. ~ 6. The fuel cell electrode according to claim 1.
8. 6. the material of the oxygen permeable membrane of the cathode includes poly 4-methyl-1-pentene; 3. The electrode for a fuel cell according to item 2.
9. The fuel cell uses livestock excrement as fuel. ~ 8. The fuel cell electrode according to claim 1.
10. The material of the electrode catalyst of the air electrode includes one or more metals selected from the group consisting of Ru, Rh, Ir, Ni, Pd, Pt, Cu, Ag and Au. ~ 9. The fuel cell electrode according to claim 1.
11. 9. The material of the electrode catalyst of the air electrode includes Pt. 3. The electrode for a fuel cell according to item 2.
12. 10. in the air electrode, a layer of the electrode catalyst containing Pt is provided on a surface of the conductive substrate; 3. The electrode for a fuel cell according to item 2.
13.1. ~ 12. A fuel cell comprising the fuel cell electrode according to claim 1.
14． 12. Does not include a proton conducting membrane as a component. A fuel cell according to claim 1.
15. An air electrode, a fuel electrode, and a method for manufacturing an electrode used for an air electrode of a fuel cell including an electrolytic solution disposed between the air electrode and the fuel electrode,
A step of bonding the conductive substrate and the oxygen-permeable film by pressing the conductive substrate and the oxygen-permeable film in direct contact with each other,
Immobilizing an electrode catalyst on the conductive substrate,
A method for producing an electrode for a fuel cell, comprising:
16. 14. the step of immobilizing the electrode catalyst on the conductive substrate includes the step of forming a layer of the electrode catalyst containing Pt on the surface of the conductive substrate by a sputtering method or an electrode reduction method; 3. The method for producing an electrode for a fuel cell according to item 1.
17． 15. The step of forming a layer of an electrode catalyst is a step of forming the layer containing Pt by the sputtering method. 3. The method for producing an electrode for a fuel cell according to item 1.

This application claims priority based on Japanese Patent Application No. 2018-145690 filed on Aug. 2, 2018, the entire disclosure of which is incorporated herein.

DESCRIPTION OF SYMBOLS 10 Fuel cell 11 Fuel electrode 12 Electrolyte 13 Air electrode 14 Oxygen permeable film 145 Oxygen permeable film / conductive base material mixed layer 15 Conductive base material 16 Atmosphere 17 External resistance 18 Container 19 Electrode catalyst layer 21a Heating plate 21b Heating plate

Claims (20)

An air electrode, a fuel electrode, and an electrode used for a fuel cell including an electrolytic solution disposed between the air electrode and the fuel electrode,
The air electrode includes a conductive substrate, an electrode catalyst and an oxygen permeable membrane,
(A) oxygen permeable membrane layer (AB) oxygen permeable membrane / conductive base material mixed layer (B) conductive base material layer (C) electrode catalyst layer
The fuel cell electrode, wherein the layer (A) is a thermoplastic resin layer, and the thickness of the layer (A) is 0.1 μm or more and 280 μm or less. An air electrode, a fuel electrode, and an electrode used for a fuel cell including an electrolytic solution disposed between the air electrode and the fuel electrode,
Including a conductive substrate, an electrode catalyst and an oxygen permeable membrane,
An electrode for a fuel cell, wherein the conductive substrate and the oxygen permeable membrane are in direct contact with each other and pressure-bonded. (3) The electrode for a fuel cell according to (2), wherein the thickness of the oxygen permeable film is 0.1 μm or more and 1000 μm or less. 3. The fuel cell electrode according to claim 1, wherein the material of the conductive substrate of the air electrode is a carbon material. 3. The fuel cell electrode according to claim 2, wherein the oxygen permeable membrane contains a thermoplastic resin. 6. The fuel cell according to claim 1, wherein the oxygen permeable membrane contains a thermoplastic resin having at least one of a melting point and a glass transition temperature in a range of 100 to 300 ° C. determined by a differential scanning calorimeter. electrode. The material of the oxygen permeable membrane of the air electrode includes any one resin selected from the group consisting of poly-4-methyl-1-pentene, polybutene, polytetrafluoroethylene, and polydimethylsiloxane. 6. The electrode for a fuel cell according to 5. 6. The fuel cell electrode according to claim 1, wherein the material of the oxygen permeable membrane of the air electrode includes poly-4-methyl-1-pentene. The material of the electrode catalyst of the air electrode includes one or more metals selected from the group consisting of Ru, Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au, according to claim 1 or 2, The electrode for a fuel cell according to the above. The electrode for a fuel cell according to claim 9, wherein the material of the electrode catalyst of the air electrode includes Pt. The fuel cell electrode according to claim 10, wherein, in the air electrode, a layer of the electrode catalyst containing Pt is provided on a surface of the conductive substrate. The fuel cell electrode according to claim 1 or 2, wherein the fuel electrode includes a conductive substrate on which power-generating bacteria can be fixed. 13. The fuel cell electrode according to claim 12, wherein the fuel electrode includes a conductive base material and a power generation bacterium as an electrode catalyst. 13. The fuel cell electrode according to claim 12, wherein the fuel electrode includes a conductive substrate made of a carbon material. The fuel cell electrode according to any one of claims 1, 2 and 12, wherein the fuel cell uses livestock excrement as fuel. A fuel cell comprising the fuel cell electrode according to any one of claims 1, 2, 12, and 15. 17. The fuel cell according to claim 16, wherein the fuel cell does not include a proton conducting membrane as a component. An air electrode, a fuel electrode, and a method for manufacturing an electrode used for an air electrode of a fuel cell including an electrolytic solution disposed between the air electrode and the fuel electrode,
A step of bonding the conductive substrate and the oxygen-permeable film by pressing the conductive substrate and the oxygen-permeable film in direct contact with each other,
Immobilizing an electrode catalyst on the conductive substrate,
A method for producing an electrode for a fuel cell, comprising: 19. The step of immobilizing the electrode catalyst on the conductive substrate includes forming a layer of the electrode catalyst containing Pt on the surface of the conductive substrate by a sputtering method or an electrode reduction method. 3. The method for producing an electrode for a fuel cell according to item 1. 20. The method according to claim 19, wherein the step of forming the electrode catalyst layer is a step of forming the layer containing Pt by the sputtering method.

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