JP2006120509A - Catalyst electrode, method for producing catalyst electrode, and fuel cell using the catalyst electrode - Google Patents

Abstract

In a catalyst electrode used in a fuel cell, a highly efficient catalyst electrode is obtained by optimizing the diffusibility of fuel and the three-phase interface.
A catalyst electrode 10 is formed by forming a catalyst layer 14 composed of an electrolyte 13 and catalyst particles 12 which are uniformly dispersed in a solvent in advance and adjusted on an electrode substrate 11. At this time, since the amount of the electrolyte 13 is small and the pores 15 are large on the electrode substrate 11 side, the fuel diffusibility is good. And the quantity of the electrolyte 13 increases relatively toward the conductive electrolyte membrane 2 from the electrode base material 11 side, the void | hole 15 reduces, and, thereby, a three-phase interface increases. According to this configuration, in the catalyst layer 14, a region with good fuel diffusibility and a region with many active three-phase interfaces can be formed in the thickness direction. In another example, in the above configuration, the particle diameter of the catalyst particles 12 may be decreased in the thickness direction of the catalyst electrode 10 from the electrode base material 11 toward the conductive electrolyte membrane 2.
[Selection] Figure 2

Description

  The present invention relates to a catalyst electrode, a method for producing the catalyst electrode, and a fuel cell using the catalyst electrode, and more particularly, a catalyst that is applied to the fuel cell and optimizes the form of the fuel diffusibility and the three-phase interface. The present invention relates to an electrode, a method for producing the catalyst electrode, and a fuel cell to which the catalyst electrode is applied.

  From the viewpoint of environmental problems represented by greenhouse gases, fuel cells as clean energy sources have been developed at a rapid pace. In particular, solid oxide fuel cells are actively researched and developed because of their low-temperature operation characteristics, small size, and high power density. Among them, in the manufacture of a fuel cell electrode, high diffusibility of fuel to the electrode layer and formation of a three-phase interface are indispensable elements for stable operation of the fuel cell.

  Therefore, conventionally, as a form of the catalyst layer between the electrode substrate and the electrolyte layer, a catalyst particle layer having a particle size gradient from the electrode substrate toward the electrolyte layer has been disclosed (for example, Patent Document 1) has improved the diffusibility of fuel. Further, Patent Document 1 mentions that the surface area of the catalyst particles at the interface with the electrolyte layer is increased by reducing the particle size of the catalyst particles on the electrolyte layer side. The three-phase interface formed by the catalyst particles and the electrolyte that causes a reaction has not been improved.

On the other hand, as a conventional method for stacking and forming catalyst layers, there is a method of manufacturing an electrode by spraying catalyst powder pulverized by a pulverizer (for example, Patent Document 2). However, it is difficult to continuously form a catalyst layer using powder pulverized by a pulverizer, and a three-phase interface is not efficiently formed.
Japanese Patent Laid-Open No. 2-18862 JP 2001-160402 A

The present invention has been made to solve such a problem.
The purpose of the present invention is to provide a catalyst electrode that can be used in a fuel cell, in which the diffusibility of the fuel and the form of the three-phase interface are optimized depending on the location.
Still another object of the present invention is that the catalyst electrode has good fuel diffusibility on the electrode substrate side of the catalyst electrode, and more three-phase interfaces are formed on the electrolyte membrane side where the catalyst electrode is laminated. It is to provide an electrode.

Still another object of the present invention is to provide a catalyst electrode having high catalyst performance in the above catalyst electrode.
Still another object of the present invention is to efficiently produce the catalyst layer of the catalyst electrode.
Still another object of the present invention is to provide a fuel cell that can optimize the diffusibility of the fuel and the form of the three-phase interface and can operate stably with high efficiency.

Still another object of the present invention is to provide a fuel cell in which the driving time is improved by using a liquid fuel having a high energy density in the above fuel cell.
Still another object of the present invention is to provide a fuel cell having high environmental conservation and safety in the above fuel cell.

  In order to solve the above problems, the invention of claim 1 is a catalyst electrode comprising an electrode base material and a catalyst layer formed on the electrode base material, wherein the catalyst layer comprises an electrolyte, Particles having a catalytic function, and a relatively large amount of the electrolyte contained in the catalyst layer is present on the opposite side of the electrode substrate in the thickness direction of the catalyst layer.

  According to a second aspect of the present invention, in the catalyst electrode according to the first aspect, the particles having the catalytic function have a relatively large particle size on the electrode base material side in the thickness direction of the catalyst layer. .

  According to a third aspect of the present invention, in the catalyst electrode according to the first or second aspect, the particles having the catalytic function are carbon particles supporting a metal catalyst.

  According to a fourth aspect of the present invention, there is provided the catalyst electrode according to any one of the first to third aspects, wherein the catalyst layer changes the composition of the particles having the catalytic function, the electrolyte, and the solvent. It is formed by spraying on a material.

  According to a fifth aspect of the present invention, there is provided a method for producing a catalyst electrode according to any one of the first to third aspects, wherein the catalyst layer comprises particles having the catalytic function, the electrolyte, and a solvent. It is characterized in that it is formed by spraying the electrode base material while changing the composition.

  According to a sixth aspect of the present invention, there is provided a fuel cell having a laminated body in which an electrolyte layer is sandwiched from both sides by a catalyst electrode, and generating power by supplying fuel to the laminated body. Or the catalyst electrode according to any one of 1 to 4 above.

  The invention according to claim 7 is the fuel cell according to claim 6, wherein the fuel contains alcohol.

  According to an eighth aspect of the present invention, in the fuel cell according to the seventh aspect, the fuel contains ethanol.

According to the catalyst electrode of the present invention, it is possible to provide a catalyst electrode in which the diffusibility of the fuel and the form of the three-phase interface are optimized depending on the location.
Furthermore, according to the catalyst electrode of the present invention, in the above catalyst electrode, the diffusibility of fuel is good on the electrode substrate side of the catalyst electrode, and more three-phase interfaces are formed on the electrolyte membrane side where the catalyst electrode is laminated. The catalyst electrode can be provided.

Furthermore, according to the catalyst electrode of the present invention, a catalyst electrode having high catalyst performance can be provided.
Further, according to the method for producing a catalyst electrode of the present invention, the catalyst layer of the catalyst electrode can be produced efficiently.
In addition, according to the fuel cell of the present invention, the above-described catalyst electrode optimizes the diffusibility of the fuel and the form of the three-phase interface, and can provide a fuel cell that can operate stably with high efficiency.

Furthermore, according to the fuel cell of the present invention, it is possible to provide a fuel cell that improves the driving time by using a liquid fuel having a high energy density in the above fuel cell.
Furthermore, according to the fuel cell of the present invention, in the above fuel cell, a fuel cell having high environmental conservation and safety can be provided.

  Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. Note that in all the drawings for describing the embodiments, the same reference numerals are given to portions having the same functions, and repeated description thereof is omitted.

Taking a fuel cell using a proton conducting electrolyte as an example, a conceptual diagram of power generation is shown in FIG.
In FIG. 1, 1 is a fuel cell, 2 is a conductive electrolyte membrane, 3 is an anode, 4 is a cathode, 5 is an anode side separator, 6 is a cathode side separator, and 7 is a flow path for anode fuel (mainly hydrogen or alcohol). And a groove serving as a flow path for 8-cathode fuel (mainly air and oxygen) and produced water. The power generation unit of the fuel cell is actually configured as a cell stack in which a large number of cells configured like the fuel cell main body 1 as described above are stacked.

  The fuel cell 1 has, as its basic constituent elements, a conductive electrolyte membrane 2 made of an ion conductor (proton conductor in the case of FIG. 1) at the center, and an anode 3 and a cathode 4 arranged on both sides thereof. have. The anode 3 and the cathode 4 are usually configured to have a diffusion layer and a catalyst, and while diffusing fuel in the diffusion layer, the reaction is promoted by the catalyst. For example, the anode 3 is configured as a fuel electrode composed of a carbon electrode to which catalyst fine particles such as platinum and platinum / ruthenium are adhered, and the cathode 4 is configured as an air electrode composed of a carbon electrode to which catalyst fine particles such as platinum are adhered. In addition, the conductive electrolyte membrane 2 is configured by, for example, a film-like ion conductive film (exchange membrane) interposed between the anode 3 and the cathode 4.

  When a proton-conducting electrolyte is used for the conductive electrolyte membrane 2, when anode fuel (hydrogen, alcohol, etc.) serving as a proton source is supplied to the anode 3, hydrogen is supplied from the anode fuel by the catalytic action in the anode 3. Ions are generated. At this time, the generated electrons flow out to the external circuit. The generated hydrogen ions propagate through the conductive electrolyte membrane 2 and reach the cathode 4. When cathode fuel made of an oxidant (air, oxygen, etc.) is supplied to the cathode 4, hydrogen ions, oxygen, and electrons flowing through the external circuit react to generate water. The above is the concept of power generation, which can be expressed as a reaction formula as follows.

Anode reaction; H ₂ → 2H ⁺ + 2e ⁻ (in the case of hydrogen fuel)
Cathode reaction: 2H ⁺ + 1 / 2O ₂ + 2e ⁻ → H ₂ O
Total reaction: H ₂ + 1 / 2O ₂ → H ₂ O

  In order for the reaction shown in the above formula to proceed, the interface between the fuel, the catalyst, and the electrolyte (three parts) is formed in a laminate in which the conductive electrolyte membrane 2 is sandwiched by the electrodes (anode 3 and cathode 4) of the fuel cell. It is necessary that the phase interface is sufficiently formed and that the fuel is diffusible. This is because electrons are transferred only at this three-phase interface, and fuel molecules permeate through a thin layer of electrolyte and are activated on the surface of the catalyst to give electrons to the electrode. Proton ions such as protons diffuse through the electrolyte. Propagate. In order to execute this efficiently, it is essential to form three phases of “fuel”, “conductor catalyst that activates the fuel and propagates electrons”, and “electrolyte that propagates protons”.

  Actually, even if there is a thin electrolyte layer on the surface of the catalyst, hydrogen permeates through this layer, so the reaction proceeds even in the absence of fuel diffusing vacancies. It can be said that it is performed at the interface. Furthermore, in the case of liquid fuels such as methanol and ethanol, the reaction similarly occurs because the electrolyte layer penetrates. In order to more effectively form this three-phase interface and obtain electrical characteristics, the structure of the electrode is important, and various studies have been made on this point.

  Up to now, it has been proposed to gradually reduce the particle size of the catalyst particles from the electrode substrate side of the electrode toward the electrolyte layer, but without changing the composition of the electrolyte and catalyst particles. When it is contained in the electrode, the surface area of the catalyst increases as the particle size of the catalyst particles decreases, but the electrolytic mass that is an element of the three-phase interface is not adjusted. Therefore, the present invention has proposed a catalyst electrode in which the electrolyte is optimally adjusted with respect to the catalyst particles in order to further improve the power generation characteristics.

  FIG. 2 is a schematic view for explaining an embodiment of the catalyst electrode of the present invention. In the figure, 10 is a catalyst electrode, 11 is an electrode substrate, 12 is catalyst particles, 13 is an electrolyte, and 14 is catalyst particles 12. And a catalyst layer 15 containing the electrolyte 13 and 15 are pores. The catalyst electrode 10 can be applied to the anode 3 and the cathode 4 in the fuel cell shown in FIG. 1 to form a conductive electrolyte electrode sandwich.

  The catalyst electrode 10 shown in FIG. 2 has a catalyst layer 14 composed of an electrolyte 13 and catalyst particles 12 that are uniformly dispersed and adjusted in advance in a solvent on an electrode substrate 11 made of carbon paper or carbon cloth. Form. In addition to the catalyst particles 12 and the electrolyte 13, the component that forms the catalyst layer 14 may include a binder. At this time, since the amount of the electrolyte 13 is small and the pores 15 are large on the electrode substrate 11 side, the fuel diffusibility is good. And the quantity of the electrolyte 13 increases relatively toward the conductive electrolyte membrane 2 from the electrode base material 11 side, the void | hole 15 reduces, and, thereby, a three-phase interface increases. And in the joint surface with the conductive electrolyte membrane 2, the smooth joint surface without the void | hole 15 is formed. According to this configuration, in the catalyst layer 14, a region with good fuel diffusibility and a region with many active three-phase interfaces can be formed in the thickness direction.

FIG. 3 is a schematic view for explaining another embodiment of the catalyst electrode of the present invention. In the present embodiment, in the thickness direction of the catalyst layer 14, the particle diameter is gradually decreased from the electrode substrate 11 side toward the conductive electrolyte membrane 2 without changing the weight of the catalyst particles 12.
That is, when the particle size of the catalyst particles 12 is reduced in the thickness direction of the catalyst layer 14, the surface area of the catalyst particles 12 increases when the weight of the contained catalyst particles 12 is constant. Then, the amount of the electrolyte 13 is increased according to the increased surface area of the catalyst particles 12. As a result, even in the vicinity of the conductive electrolyte membrane 2, the electrolyte 13 can sufficiently exist around the catalyst particles 12, so that more three-phase interfaces can be formed. Further, a large number of pores 15 are formed in a region where the particle size of the catalyst particles 12 is large, and a small amount of the pores 15 is formed in a region where the particle size of the catalyst particles 12 is small. Thereby, the diffusion of fuel can also be executed efficiently.

  The catalyst particles of the present invention are preferably those in which a metal catalyst such as Pt or Ru is supported on carbon particles, and the amount of the catalyst according to the surface area of the carbon particles is adjusted by adjusting the particle size of the carbon, As a result, the formation of the three-phase interface can be adjusted.

Next, an embodiment of a method for forming the catalyst layer 14 will be described.
As a method for forming the catalyst layer 14, it is generally considered to apply application by a blade or screen printing or the like, but when the composition is changed in the thickness direction of the catalyst layer 14 as in the present invention. The catalyst layer 14 needs to be divided into several layers. In this case, when the catalyst layer 14 having a certain degree of viscosity is applied with the above-described blade or the like, the lower layer needs to be sufficiently dried and fixed before the layers are stacked. Cost. That is, the coating liquid having a viscosity capable of adjusting the pores 15 is dried to form a layer after coating, but the coating layer is dried from the surface, and it takes time to dry the inside of the layer. The formation process takes time. In addition, since the coating layer is dried from the surface and a force is applied to the surface to be coated in the thickness direction, formation of the holes 15 becomes difficult.

  In the embodiment of the present invention, the catalyst layer 14 is preferably formed by spraying such as spray coating. In the spray method, pores with good diffusibility can be obtained by adjusting the spray liquid by appropriately selecting the type and blending amount of the dispersion solvent and the blending amount of the catalyst-supporting particles and the electrolyte, and selecting an appropriate spraying amount and speed. The catalyst layer 14 having 15 can be formed efficiently. It is considered that this is because when the spray liquid is sprayed, the viscosity of the spray liquid increases during the spraying, so that the pores 15 are easily maintained in the formed catalyst layer 14. In addition, the environment in which the layer is formed by spraying may be room temperature, and the viscosity of the sprayed droplets and the drying speed of the formed layer may be adjusted by adjusting the temperature.

FIG. 4 is a schematic diagram for explaining an example of a layer forming process for forming a catalyst layer. In the figure, 16 is a spray solution adjusted to form a catalyst layer, and 21 and 22 are spray solutions. It is a spray nozzle for spraying.
In order to form the catalyst layer 14, the spray solution adjusted according to the target layer composition is sprayed from the spray nozzles 21 and 22 while adjusting the amount and time, and the layer is formed on the electrode substrate 11. The dispersion solvent contained in the spray liquid is quickly dried by spraying, and the catalyst layer 14 can be efficiently produced by a continuous process.

  A fuel cell can be produced using the catalyst electrode formed as described above. The fuel used in the fuel cell is appropriately set in accordance with the fuel cell. However, it is preferable to use a fuel excellent in volume and weight energy density, and in particular, use a fuel excellent in volume density. It is preferable. Therefore, gaseous fuel is not preferable because it is inferior in volumetric energy density, and it is preferable to use liquid fuel or solid fuel.

  For example, the number of electrons that can be extracted from an oxidation reaction of one molecule is 2 for hydrogen, 6 for methanol, and 12 for ethanol. The theoretical values are 96500 × 2C, 96500 × 6C, and 96500 × 12C. When each density and molecular weight are taken into consideration and converted into the amount of coulomb per cc, the energy density is about 9 C / cc for hydrogen, about 14400 C / cc for methanol, and 15200 C / cc for ethanol. That is, hydrogen as a normal pressure gas has an extremely low energy density per unit volume. Methanol and ethanol each require one molecule and three molecules of water for the oxidation reaction (the following formula), but it is clear that liquid fuel is excellent even when this is added.

CH ₃ OH + H ₂ O → 6H ⁺ + 6e ⁻ + CO _{2
C 2 H 5 OH + 3H 2} O → 12H + + 12e - + 2CO 2

Although it is possible to use high-pressure hydrogen or liquid hydrogen as the fuel, it is necessary to make the container robust, and considering the energy density of the container, liquid or solid fuel at room temperature and normal pressure After all it is excellent.
Specifically, hydrogen, gasoline, liquid hydrocarbons, liquid alcohol, and other solid fuels stored in hydrogen storage alloys can be used, but fuel cells can be miniaturized, and volume energy It is preferable to use alcohol fuel because of its excellent density.
By using alcohol fuel, it becomes possible to improve the driving time of the fuel cell. Among these, it is preferable to use an alcohol having 4 or less carbon atoms. In this case, it is more preferable to use ethanol in view of high safety and biosynthesis (environmental aspect). The fuel cell using the electrode prepared according to the present invention has better fuel diffusibility than the conventional one and efficiently supplies the fuel to the catalyst layer. That is, the diffusibility is significantly improved in the liquid fuel that is difficult to diffuse compared with the gas fuel.

FIG. 5 is a schematic diagram for explaining a configuration example of a power supply system using the fuel cell as described above.
The fuel container 50 is filled with anode fuel 51. In this example, air is used as the cathode fuel, and liquid fuel (alcohols) containing hydrogen such as ethanol is used as the anode fuel. The fuel container 50 is connected to the power generation module 30 provided with the fuel cell main body 1, and can drive the load 40 by electric energy generated by the power generation module 30.

  The power generation module 30 includes a fuel cell main body 1 that is a power generation unit, an output control unit 32 for controlling the output of the fuel cell main body 1, and an operation for controlling the operation of the output control unit 32 in accordance with the driving state of the load 40. And a control unit 31.

  In the power generation module 30, the operation control unit 31 controls the power generation state of the fuel cell main body 1 based on information on the drive state of the load 40 (load drive information). Specifically, the operation control unit 31 causes the output control unit 32 to activate the fuel cell body 1 when detecting a command to activate the load 40 in a state where the fuel cell body 1 is not driven. When an operation control signal is output and a command to stop the load 40 is detected while the fuel cell main body 1 is driven, the output control unit 32 is configured to stop the fuel cell main body 1. An operation control signal is output.

  Further, when the operation control unit 31 detects a change in the driving state of the load 40 while the fuel cell main body 1 is being driven, the operation control unit 31 causes the output control unit 32 to change from the fuel cell main body 1 to the load 40. An operation control signal for adjusting the generation amount (power generation amount) of the electric energy in the fuel cell main body 1 is output so that the supplied electric energy becomes an appropriate value corresponding to the driving state of the load 40.

  The output control unit 32 controls the supply amount of power generation fuel (anode fuel) to the fuel cell main body 1 based on the operation control signal from the operation control unit 31 and the fuel cell main body 1. An air control unit 34 for controlling the supply amount of the cathode fuel (here, air), a reforming unit 35 for reforming the anode fuel, gasifying and supplying hydrogen contained in the anode fuel, and liquid fuel. And a sub-power generation unit 36 that supplies power to the fuel control unit 33, the air control unit 34, and the reforming unit 35 at least when the load 40 is off. ing.

  The sub power generation unit 36 is a direct fuel cell that generates power by directly supplying liquid fuel sent by capillary action from a pipe communicating with the fuel container 50 without a reformer, or liquid sent from the fuel container 50. It can be constituted by a gas turbine type or rotary engine type generator that generates electricity by rotating the turbine with a pressure that rises when the fuel is vaporized. The sub power generation unit 36 supplies power necessary for the operation control unit 31 to monitor the load drive information to the operation control unit 31 and supplies standby power to the load 40 when the load 40 is off. To do.

  The air control unit 34 may be set so that the amount of oxygen gas to be supplied to the cathode 4 of the fuel cell main body 1 is electrically driven by a pump and supplied per unit time in the fuel cell main body 1. As long as the air (atmosphere) corresponding to the maximum consumption of oxygen can be supplied, the air and the fuel cell main body 1 may be configured as a vent hole. By configuring so that the amount of air used for the electrochemical reaction in the fuel cell main body 1 is always supplied via the vent hole, the output control unit 32 changes the progress of the electrochemical reaction only to the fuel control unit 33. Can be controlled.

Note that the driving power supplied to the load 40 by the electrochemical reaction as described above depends on the amount of hydrogen gas (H ₂ ) supplied to the anode 3 of the fuel cell body 1 in the system of FIG. Therefore, by controlling the amount of hydrogen gas (H ₂ ) supplied to the anode 3 of the fuel cell main body 1 by the reforming unit 35, that is, by controlling the amount of anode fuel by the fuel control unit 33, the load The electrical energy supplied to 40 can be arbitrarily adjusted.
FIG. 6 is a schematic diagram for explaining another configuration example of the power supply system using the fuel cell. The fuel control unit 33 directly attaches the fuel cell body 1 to the fuel cell body 1 without using the reforming unit 35 of FIG. 1 shows a configuration for supplying anode fuel. In the direct liquid fuel supply system of FIG. 6, it depends on the amount of liquid fuel supplied to the anode 3 of the fuel cell main body 1. Therefore, the electric energy supplied to the load 40 can be arbitrarily adjusted by controlling the amount of anode fuel by the fuel control unit 33. The other elements in FIG. 6 are the same as those in FIG.

  As described above, according to the present invention, the fuel diffusibility and the form of the three-phase interface are optimized, and a fuel cell that can operate stably with high efficiency can be provided, and the size and weight can be reduced. .

Example 1
A uniform catalyst layer solution in which Pt-supported carbon, an electrolyte solution (Nafion solution, manufactured by Dupon) and glycerin were mixed was prepared. Here, three types of catalyst layer liquids in which the amount of the electrolyte liquid with respect to Pt per unit volume is increased in stages are prepared, and sprayed from the nozzle in order of decreasing electrolyte liquid on the electrode substrate 11, and shown in FIG. The structure of the catalyst electrode 10 was formed. As a result, a catalyst electrode 10 of 1 mg / cm ² of Pt per unit area was obtained. The obtained catalyst electrode 10 was placed on both sides of the conductive electrolyte membrane (Nafion 115, manufactured by Dupon Co.) and hot pressed to produce a joined body of the conductive electrolyte membrane 2 and the catalyst electrode 10. The obtained joined body was sandwiched between separators to obtain a fuel cell A.

(Comparative Example 1)
As a comparative example, a catalyst layer solution in which Pt-supported carbon, an electrolyte solution (Nafion solution, manufactured by Dupon) and glycerin were mixed was prepared. Here, the adjustment liquid was blade-coated on the electrode substrate 11 to form a catalyst electrode 10 having a constant amount of electrolyte solution relative to Pt per unit volume as shown in FIG. As a result, a catalyst electrode 10 of 1 mg / cm ² per unit area was obtained. The obtained catalyst electrode 10 was placed on both sides of the conductive electrolyte membrane (Nafion 115, manufactured by Dupon Co.) and hot pressed to obtain a joined body of the conductive electrolyte membrane 2 and the catalyst electrode 10. The obtained joined body was sandwiched between separators to obtain a comparative fuel cell B.

(Example 2)
A uniform catalyst layer solution in which Pt-supported carbon, an electrolyte solution (Nafion solution, manufactured by Dupon) and glycerin were mixed was prepared. Here, three types of catalyst layer solutions were prepared in which the amount of the electrolyte solution relative to Pt per unit volume was increased stepwise, and the particle size of the catalyst-supporting carbon contained was changed stepwise, The structure of the catalyst electrode 10 shown in FIG. 3 was formed by spraying from the nozzle in ascending order of the electrolyte solution on the material 11. As a result, a catalyst electrode 10 of 1 mg / cm ² per unit area was obtained. The obtained catalyst electrode 10 was placed on both sides of the conductive electrolyte membrane (Nafion 115, manufactured by Dupon Co.) and hot pressed to produce a joined body of the conductive electrolyte membrane 2 and the catalyst electrode 10. The obtained joined body was held between separators to obtain a fuel cell C.

The fuel cells A (Example 1), B (Comparative Example 1), and C (Example 2) were used and operated using an aqueous ethanol solution and oxygen (air) as fuel, and their electrical characteristics were measured.
As a result, the output was higher in the order of the fuel cells C, A, and B, and the output of A was 5% and that of C was 10% higher than that of the fuel cell B of Comparative Example 1.
From the above results, when the fuel is supplied at the same flow rate, the fuel utilization rate increases in the order of C, A, and B, and the fuel cell according to the embodiment of the present invention consumes fuel efficiently due to diffusivity and interface formation. It can be said that.

It is a figure for demonstrating the electric power generation concept of the fuel cell using a proton conductive electrolyte. It is the schematic for demonstrating one Embodiment of the catalyst electrode of this invention. It is the schematic for demonstrating other embodiment of the catalyst electrode of this invention. It is the schematic for demonstrating an example of the layer formation process for forming a catalyst layer. It is the schematic for demonstrating the structural example of the power supply system which uses a fuel cell. It is the schematic for demonstrating the other structural example of the power supply system which uses a fuel cell. It is the schematic for demonstrating the structural example of the catalyst electrode of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 2 ... Conductive electrolyte membrane, 3 ... Anode, 4 ... Cathode, 10 ... Catalyst electrode, 11 ... Electrode base material, 12 ... Catalyst particle, 13 ... Electrolyte, 14 ... Catalyst layer, 15 ... Hole, 16 ... Spraying liquid, 21, 22 ... Spray nozzle, 30 ... Power generation module, 31 ... Operation control unit, 32 ... Output control unit, 33 ... Fuel control unit, 34 ... Air control unit, 35 ... Reforming unit, 36 ... Sub power generation 40, load, 50, fuel container, 51, anode fuel, 115, Nafion.

Claims (8)

  A catalyst electrode comprising an electrode substrate and a catalyst layer formed on the electrode substrate, wherein the catalyst layer includes an electrolyte and particles having a catalyst function, and is included in the catalyst layer A catalyst electrode characterized in that a relatively large amount of the electrolyte is present on the opposite side of the electrode substrate in the thickness direction of the catalyst layer.   2. The catalyst electrode according to claim 1, wherein the particles having a catalytic function have a relatively large particle size on the electrode base material side in the thickness direction of the catalyst layer.   3. The catalyst electrode according to claim 1, wherein the particles having a catalytic function are carbon particles carrying a metal catalyst.   4. The catalyst electrode according to claim 1, wherein the catalyst layer is formed by spraying the electrode base material while changing the composition of the particles having the catalytic function, the electrolyte, and the solvent. 5. A catalyst electrode characterized by being made.   The method for producing a catalyst electrode according to any one of claims 1 to 3, wherein the catalyst layer changes the composition of the particles having the catalytic function, the electrolyte, and the solvent, It forms by spraying on the said electrode base material, The manufacturing method of the catalyst electrode characterized by the above-mentioned.   5. A fuel cell having a laminate in which an electrolyte layer is sandwiched between catalyst electrodes from both sides, and generating power by supplying fuel to the laminate, wherein the catalyst electrode is defined in any one of claims 1 to 4. A fuel cell comprising the catalyst electrode as described.   The fuel cell according to claim 6, wherein the fuel contains alcohol.   8. The fuel cell according to claim 7, wherein the fuel contains ethanol.