JP3433172B2 - Polymer electrolyte fuel cell - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid polymer fuel cell, and more particularly, to an electrolyte membrane having an aromatic hydrocarbon polymer ion exchange component and an electrolyte membrane sandwiching the electrolyte membrane. And aromatic carbonization
The hydrogen-based polymer ion-exchange component and a including air electrode and the fuel electrode, about that so as to humidify only from the fuel electrode side. Conventionally, as the air electrode and the fuel electrode, a polymer ion exchange component which imparts proton conductivity to both electrodes and functions as a binder, and a catalyst metal supported on the surface of carbon black particles What consists of a plurality of catalyst particles and PTFE (polytetrafluoroethylene) particles is known. The PTFE particles have water repellency and have a function of adjusting the water retention of the air electrode and the fuel electrode. In order to maintain the proton conductivity of the electrolyte membrane while maintaining the electrolyte membrane in a wet state, conventionally, air and hydrogen are humidified and then supplied to the air electrode and the fuel electrode, respectively. Is adopted. [0004] However, the use of PTFE particles as components of the air electrode and the fuel electrode means that the thickness of the air electrode and the fuel electrode must be reduced in order to further improve the power generation performance. This has been an obstacle in meeting the requirements of increasing proton conductivity and reducing resistance overvoltage. Further, according to the conventional humidifying means, the humidifier must be installed by performing a troublesome sealing operation on each of the air supply line and the hydrogen supply line, so that the equipment cost is increased and the structure is complicated. There was a problem of inviting. According to the present invention, the power generation performance can be further improved by reducing the thickness of the air electrode and the fuel electrode. It is an object of the present invention to provide the polymer electrolyte fuel cell which can be operated only by humidification from the fuel electrode side. [0007] To achieve the above object, according to the present invention,
An electrolyte membrane having an aromatic hydrocarbon-based polymer ion-exchange component, and an air electrode and a fuel electrode sandwiching the electrolyte membrane, wherein the air electrode and the fuel electrode each carry a catalytic metal on the surface of carbon black particles a plurality of catalyst particles and polymer ion-exchange component is, the polymer Lee
The on-exchange component is the aromatic hydrocarbon polymer ion exchange.
The same aromatic hydrocarbon polymer ion exchange component as the exchange component
And different aromatic hydrocarbon polymer ion exchange components
In the fuel electrode, the carbon black particles have water repellency such that the water adsorption amount A under a saturated steam pressure of 60 ° C. is A ≦ 80 cc / g, and the carbon black particles contain the polymer ion exchange component. When the weight is Wp and the blending weight of the carbon black particles is Wc, the ratio Wp / Wc of the blending weights Wp and Wc is 0.2 ≦ W.
p / Wc ≦ 0.8, and at the air electrode, the carbon black particles have a hydrophilic property such that the water adsorption amount A under a saturated steam pressure of 60 ° C. is A ≧ 150 cc / g; When the blending weight of the molecular ion exchange component is Wp and the blending weight of the carbon black particles is Wc, the ratio Wp / W of the blending weights Wp and Wc is Wp / W.
c is 0.6 ≦ Wp / Wc ≦ 1.25, and a polymer electrolyte fuel cell is provided in which humidification is performed only from the fuel electrode side. [0008] With the above configuration, it is possible to stop the use of PTFE particles by giving the water-repellent carbon black particles and the hydrophilic carbon black particles the function of adjusting the water retention of the air electrode and the fuel electrode, respectively. It is. This is effective in reducing the thickness of the cathode and anode. When the ratio Wp / Wc of the blending weights Wp and Wc at the air electrode and the fuel electrode is set as described above, the thickness of the air electrode and the fuel electrode is reduced because the PTFE particles are not included. As a result, it is possible to increase proton conductivity and suppress an increase in resistance overvoltage, thereby improving power generation performance. However, when the ratio Wp / Wc of the fuel electrode is Wp / Wc <0.2, the thickness of the fuel electrode further decreases, but the coverage of the catalyst particles deteriorates, and the power generation performance decreases. On the other hand, when Wp / Wc> 0.8, the flow of the humidifying water becomes worse due to an increase in the thickness of the fuel electrode. At the air electrode, the ratio Wp / Wc is Wp
When /Wc<0.6, water retention deteriorates, while Wp /
When Wc> 1.25, the degree of dispersion of the polymer ion-exchange component deteriorates, so that the thickness of the air electrode increases. Further, since the humidifier need only be provided on the side of the hydrogen supply pipe, the equipment cost can be reduced and the structure can be simplified. In this case, when humidification is performed from the fuel electrode side, the humidified water smoothly flows into the electrolyte membrane because the carbon black particles of the fuel electrode are water repellent, and flows into the electrolyte membrane of the generated water of the air electrode. Is also generated, so that the electrolyte membrane is in a wet state. On the other hand, since the carbon black particles in the air electrode are hydrophilic, a part of the generated water and the water flowing into the air electrode from the electrolyte membrane are retained therein. The electrolyte membrane is kept in a wet state by the water in the air electrode and the humidification of the fuel electrode. At the cathode and anode,
Excess water is discharged to the outside. However, at the fuel electrode, when the water adsorbed amount A of the carbon black particles is A> 80 cc / g, the water repellency is reduced and the flow of the humidified water is deteriorated. The water adsorption amount A is A <
At 150 cc / g, the hydrophilicity decreases and the water retention becomes insufficient. FIG. 1 shows a polymer electrolyte fuel cell (cell) 1 having an electrolyte membrane 2 and an air electrode 3 and a fuel electrode which are in close contact with both sides of the electrolyte membrane 2 respectively. 4 and a pair of diffusion layers 5 and 6 that are in close contact with both electrodes 3 and 4, respectively, and a pair of separators 7 and 8 that are in close contact with both diffusion layers 5 and 6. In this case, humidification is performed only from the fuel electrode 4 side. In the embodiment, the electrolyte membrane-electrode assembly 9 includes the electrolyte membrane 2, the air electrode 3, the fuel electrode 4, and both diffusion layers 5 and 6. [0015] The electrolyte membrane 2 is constituted by Kaoru <br/> aromatic hydrocarbon-based polymer ion-exchange components that have a proton conductivity. Air electrode 3 and the fuel electrode 4, respectively, has a function as a plurality of catalyst particles and the proton conductivity and a binder obtained by supporting Pt particles as multiple catalytic metal on the surface of carbon black particles, and the same as the or it consists <br/> different that Kaoru aromatic hydrocarbon-based polymer ion-exchange components, not including PTFE particles is the third component. Each of the diffusion layers 5 and 6 is made of a porous carbon paper or a carbon plate, and each of the separators 7 and 8 is made of graphitized carbon so as to have the same form. 7 multiple grooves 1
0 is supplied with air, and hydrogen is supplied to a plurality of grooves 11 which are present in the separator 8 on the side of the fuel electrode 4 and intersect with the grooves 10. The aromatic hydrocarbon-based polymer ion-exchange component has the property of being fluorine-free and soluble in a solvent. Table 1 shows this type of polymer ion exchange component.
Various sulfonated aromatic hydrocarbon polymers are used. [Table 1] As the solvent, various polar solvents listed in Table 2 are used. [Table 2] At the fuel electrode 4 on the humidifying side, the carbon black particles are. It has water repellency such that the water adsorption amount A under a saturated steam pressure of 60 ° C. is A ≦ 80 cc / g. In the fuel electrode 4, when the blending weight of the aromatic hydrocarbon polymer ion exchange component is Wp and the blending weight of the carbon black particles is Wc, the ratio Wp / Wc of the blending weights Wp and Wc is 0.1. 2 ≦ Wp / Wc ≦ 0.
8 is set. On the other hand, in the air electrode 3, the carbon black particles have a hydrophilic property such that the water adsorption amount A under a saturated steam pressure of 60 ° C. is A ≧ 150 cc / g. In the air electrode 3, when the compounding weight of the aromatic hydrocarbon polymer ion-exchange component is Wp and the compounding weight of the carbon black particles is Wc, both compounding weights W
The ratio Wp / Wc of p and Wc is 0.6 ≦ Wp / Wc ≦ 1.2
Set to 5. With the above structure, the water-repellent carbon black particles and the hydrophilic carbon black particles have the function of adjusting the water retention of the air electrode 3 and the fuel electrode 4, respectively, so that the use of the PTFE particles is stopped. Is possible. This is effective in reducing the thickness of the cathode 3 and the anode 4. When the ratio Wp / Wc of the blending weights Wp and Wc in the air electrode 3 and the fuel electrode 4 is set as described above, the thickness of the air electrode 3 and the fuel electrode 4 may be reduced because the PTFE particles may not be contained. In addition, it is possible to increase the proton conductivity and reduce the rise of the resistance overvoltage to improve the power generation performance. Further, since the humidifier need only be provided on the side of the hydrogen supply pipe, the equipment cost can be reduced and the structure can be simplified. In this case, when humidification is performed from the fuel electrode 4 side,
The humidified water flows smoothly into the electrolyte membrane 2 because the carbon black particles of the fuel electrode 4 are water repellent, and the generated water of the air electrode 3 also reversely diffuses into the electrolyte membrane 2, so that the electrolyte membrane 2 becomes wet. State. On the other hand, since the carbon black particles of the air electrode 3 are hydrophilic, a part of the generated water and the water flowing from the electrolyte membrane 2 into the air electrode 3 are retained therein. The electrolyte membrane 2 is kept in a wet state by the water in the air electrode 3 and the humidification of the fuel electrode 4. At the air electrode 3 and the fuel electrode 4, excess water is discharged to the outside. Hereinafter, a specific example will be described. I- (1) Manufacture of fuel electrode Water adsorption amount A under saturated steam pressure at 60 ° C. is A = 72.
cc / g of water-repellent carbon black particles (trade name:
Vulcan XC-72) supported Pt particles to prepare fuel electrode catalyst particles. The content of Pt particles in the catalyst particles is 50% by weight. [Example-I] As the aromatic hydrocarbon polymer ion exchange component, the PEEK sulfonate listed in Example 1 in Table 1 was prepared, and this PEEK sulfonate was dissolved under reflux in NMP in Table 2. The content of the PEEK sulfonate in this solution is 6% by weight. In this PEEK sulfonate-containing solution, the ratio Wp / Wc of the blend weight Wp of the PEEK sulfonate to the blend weight Wc of the carbon black particles is Wp.
The catalyst particles were mixed so that /Wc=0.2, and then the catalyst particles were dispersed using a ball mill to prepare a fuel electrode slurry. This slurry was prepared with a Pt content of 0.5 mg / cm
^The fuel electrode 4 having a diffusion layer 6 was obtained by applying the mixture to one surface of a plurality of porous carbon papers and drying the mixture. This fuel electrode 4 is referred to as Example 1. [Example-II] The ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated product to the blending weight Wc of the carbon black particles is represented by W
Example-I except that p / Wc = 0.4 was set.
The fuel electrode 4 having the diffusion layer 6 was obtained in the same manner as described above. This fuel electrode 4 is referred to as Example 2. [Example-III] Except that the ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated compound to the blending weight Wc of the carbon black particles was set to Wp / Wc = 0.6.
Fuel electrode 4 having diffusion layer 6 was obtained in the same manner as in I. This fuel electrode 4 is referred to as Example 3. [Example-IV] The ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated product to the blending weight Wc of the carbon black particles is represented by W
Example-I except that p / Wc = 0.8 was set.
The fuel electrode 4 having the diffusion layer 6 was obtained in the same manner as described above. This fuel electrode 4 is referred to as Example 4. [Example-V] The ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated product to the blending weight Wc of the carbon black particles is represented by W
Example-except that p / Wc was set to 1.25
Fuel electrode 4 having diffusion layer 6 was obtained in the same manner as in I. This fuel electrode 4 is referred to as Example 5. [Example-VI] The ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated product to the blending weight Wc of the carbon black particles is represented by W
Example-I except that p / Wc = 2.0 was set.
The fuel electrode 4 having the diffusion layer 6 was obtained in the same manner as described above. This fuel electrode 4 is referred to as Example 6. I- (2) Manufacture of air electrode The water adsorption amount A under the saturated steam pressure of 60 ° C. is A = 37.
Pt particles were supported on hydrophilic carbon black particles (trade name: Ketjen Black EC) of 0 cc / g to prepare air electrode catalyst particles. The content of Pt particles in the catalyst particles is 50% by weight. [Example-I] As the aromatic hydrocarbon-based polymer ion-exchange component, the PEEK sulfonate listed as Example I in Table 1 was prepared, and this PEEK sulfonate was dissolved in NMP in Table 2 under reflux. The content of the PEEK sulfonate in this solution is 6% by weight. In this PEEK sulfonate-containing solution, the ratio Wp / Wc of the blend weight Wp of the PEEK sulfonate to the blend weight Wc of the carbon black particles is Wp.
The catalyst particles were mixed so that /Wc=0.4, and then dispersed using a ball mill to prepare a slurry for an air electrode. This slurry was prepared with a Pt content of 0.5 mg / cm
^The air electrode 3 having a diffusion layer 5 was obtained by applying the coating material to one surface of a plurality of porous carbon papers and drying the coating. This air electrode 3 is taken as an example (1). [Example-II] The ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated product to the blending weight Wc of the carbon black particles is represented by W
Example-I except that p / Wc = 0.6 was set.
The air electrode 3 having the diffusion layer 5 was obtained in the same manner as described above. This air electrode 3 is taken as an example (2). [Example-III] Except that the ratio Wp / Wc of the blending weight Wp of the PEEK sulfonate to the blending weight Wc of the carbon black particles was set to Wp / Wc = 0.8,
Air electrode 3 having diffusion layer 5 was obtained in the same manner as in I. This air electrode 3 is taken as an example (3). [Example-IV] The ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated product to the blending weight Wc of the carbon black particles is represented by W
Example-except that p / Wc was set to 1.25
Air electrode 3 having diffusion layer 5 was obtained in the same manner as in I. This air electrode 3 is taken as an example (4). [Example-V] The ratio Wp / Wc of the blending weight Wp of the PEEK sulfonated product to the blending weight Wc of the carbon black particles is represented by W
Example-Except that p / Wc = 1.75 was set.
Air electrode 3 having diffusion layer 5 was obtained in the same manner as in I. This air electrode 3 is taken as an example (5). II. Table 3 shows the examples 1 to 6 of the anode 4 and the example (1) of the cathode 3
Formulation weight Wp of PEEK sulfonated product related to (5)
And the ratio of the blending weight Wc of the carbon black particles Wp /
The relationship between Wc and water retention is shown. This water retention was calculated from the amount of water adsorbed by the gas adsorber at a saturated steam pressure of 60 ° C. [Table 3] FIG. 2 is a graph showing the ratio W of both compounding weights based on Table 3.
7 is a graph showing the relationship between p / Wc and the water retention of the air electrode and the fuel electrode. In the figure, Examples 1 to 6 correspond to the fuel electrode, and Examples (1) to (5) correspond to the air electrode. This is the same in the following drawings. FIG. 2 shows that when the ratio Wp / Wc of the two compounding weights is the same, the fuel electrode using water-repellent carbon particles has lower water retention than the air electrode using hydrophilic carbon particles. Further, in the air electrode and the fuel electrode, there is a tendency that the water retention increases as the ratio Wp / Wc of the blended weight increases. Table 4 shows the ratio Wp / W of the blending weights for Examples 1 to 6 of the anode 4 and Examples (1) to (5) of the cathode 3.
The relationship between c and the thickness of the air electrode 3 and the fuel electrode 4 is shown. [Table 4] FIG. 3 is a graph showing the ratio W of both compounding weights based on Table 4.
7 is a graph showing the relationship between p / Wc and the thickness of the air electrode and the fuel electrode. FIG. 3 shows that the thicknesses of the air electrode and the fuel electrode increase as the ratio Wp / Wc increases. Table 5 shows the ratio Wp / W of the blending weights for Examples 1 to 6 of the anode 4 and Examples (1) to (5) of the cathode 3.
The relationship between c and the coverage Cc of the catalyst particles is shown. [Table 5] The coverage Cc of the catalyst particles is defined as Ae, where Ae is the plane area of the air electrode and the fuel electrode, and Ac is the sum of the areas of a plurality of catalyst particles exposed on the plane of the air electrode and the fuel electrode.
Where Cc = {(Ae−Ac) / Ae} × 100
(%). FIG. 4 is a graph showing the ratio W of both compounding weights based on Table 5.
7 is a graph showing the relationship between p / Wc and the coverage Cc of catalyst particles. FIG. 4 shows that the coverage Cc of the catalyst particles increases as the ratio Wp / Wc increases. Table 6 shows the ratio Wp / W of the blending weights for Examples 1 to 6 of the anode 4 and Examples (1) to (5) of the cathode 3.
4 shows the relationship between c and the degree of dispersion D of the catalyst particles. [Table 6] The degree of dispersion D of the catalyst particles was determined by the following method. First, the theoretical Pt concentration Tp and the PEE in the catalyst particles were determined from the blending amounts of the catalyst particles and the PEEK sulfonate during the production of the air electrode 3 (or the fuel electrode 4).
The theoretical S (sulfur) concentration Ts in the K sulfonate was calculated, and then the theoretical value ratio Ts / Tp was calculated from the theoretical values. Also, the surface of the air electrode 3 etc. was observed with EPMA,
The measured Pt concentration Ap in the catalyst particles and the measured S concentration As in the PEEK sulfonate were determined by surface analysis.
From these measured values, the measured value ratio As / Ap was determined. Thereafter, the degree of dispersion D is calculated as follows: D = [{(Ts / Tp)-(As / Ap)} / (Ts /
Tp)] × 100 (%). FIG. 5 shows the ratio W of the blending weights based on Table 6.
4 is a graph showing the relationship between p / Wc and the degree of dispersion D of catalyst particles. FIG. 5 shows that the degree of dispersion D of the catalyst particles increases as the ratio Wp / Wc increases. Table 7 shows the relationship between the degree of dispersion D of the catalyst particles and the thickness of the cathode 3 and the anode 4 for Examples 1 to 6 of the anode 4 and Examples (1) to (5) of the cathode 3. . [Table 7] FIG. 6 is a graph showing the relationship between the degree of dispersion D of the catalyst particles and the thickness of the air electrode and the fuel electrode based on Table 7. FIG. 6 shows that the thickness of the air electrode and the fuel electrode increases as the degree of dispersion D of the catalyst particles increases. III. Power Generation Performance of Fuel Cell A 50 μm thick electrolyte membrane 2 was formed using the same PEEK sulfonate used in the production of the fuel electrode 4 and the air electrode 3. Further, examples 1 to 6 of the anode 4 and examples (1) to (5) of the cathode 3 are prepared.
Performs a round robin combination with the examples (1) to (5) of the air electrode 3, that is, for example 1, example 1 and example (1), example 1 and example (2)... Example By combining 1 and Example (5), 30 electrode pairs were obtained. The electrolyte membrane 2 is formed by each electrode pair, and thus a pair of the cathode 3 and the anode 4.
And hot pressing was performed under the conditions of 140 ° C., 1.5 MPa, and 1 minute to obtain an electrolyte membrane-electrode assembly 9. The polymer electrolyte fuel cell 1 was assembled using each of the electrolyte membrane-electrode assemblies 9 and power was generated under the condition that only the fuel electrode 4 was humidified to measure the relationship between the current density and the terminal voltage. In this case, since the diffusion of water greatly affects the terminal voltage, the terminal voltage at 0.8 A / cm ^2, which is the high current density side, was used as a comparison value of the terminal voltage of each battery. Table 8 shows the ratio Wp / W of the blending weights in Examples 1 to 6 of the anode 4 and Examples (1) to (5) of the cathode 4.
c, the combination of the air electrode and the fuel electrode in each battery,
And the terminal voltage at 0.8 A / cm ² . [Table 8] FIG. 7 is a graph showing the relationship between the combination of the air electrode 3 and the fuel electrode 4 and the terminal voltage based on Table 8. As is clear from Table 8 and FIG. 7, when the combination is performed between Examples 1 to 4 of the anode 4 and Examples (2) to (4) of the cathode 3, the condition is that only the anode 4 humidifies. When the polymer electrolyte fuel cell 1 is operated below, its power generation performance can be improved. For comparison, in the fuel cell 1 in which Example 3 of the fuel electrode 4 and Example (3) of the air electrode 3 were combined, power generation was performed under the condition that humidification was performed only from the air electrode 3 side. When the relationship between the current density and the terminal voltage was measured, it was found that the terminal voltage at a current density of 0.8 A / cm ² was 0.613 V. It is clear that this terminal voltage is about 11% lower than the terminal voltage of 0.691 V when the fuel electrode example 3 and the air electrode example (3) in Table 8 are combined. Based on this fact, the fuel cell 1 in which Examples 1-4 of the anode 4 and Examples (2)-(4) of the cathode 3 are combined
It is clear that the humidification is performed only from the fuel electrode 4 side. When the ratio Wp / Wc of the blended weights of the air electrode 3 and the fuel electrode 4 is set as described above, the thickness t of the fuel electrode 4 is shown in Table 4 as shown in Examples 1-4.
3 μm ≦ t ≦ 7 μm and the thickness t of the air electrode 3 is
As shown in Examples (2) to (4), 6 μm ≦ t ≦ 8 μm, and Table 5 shows that the coverage C of the catalyst particles on the fuel electrode 4 is shown in Table 5.
c is 72% ≦ Cc ≦ 97% as in Examples 1 to 4, and the coverage Cc of the catalyst particles on the air electrode 3 is 95% ≦ Cc ≦ 98% as in Examples (2) to (4). Further, from Table 6, the dispersion degree D of the catalyst particles at the fuel electrode 4 is 2% ≦ D ≦ 7% as in Examples 1 to 4, and the dispersion degree D of the catalyst particles at the air electrode 3 is as shown in Example (2). ) ~
As in (4), 5% ≦ D ≦ 8%. According to the present invention, according to the present invention, an inexpensive and inexpensive structure capable of exhibiting high power generation performance even when operated only by humidification from the fuel electrode side. , A simple polymer electrolyte fuel cell can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of a polymer electrolyte fuel cell. FIG. 2 is a graph showing a relationship between a ratio Wp / Wc of both compounding weights and water retention of an air electrode and a fuel electrode. FIG. 3 is a graph showing a relationship between a ratio Wp / Wc of both compounding weights and thicknesses of an air electrode and a fuel electrode. FIG. 4 is a graph showing a relationship between a ratio Wp / Wc of both compounding weights and a coverage Cc of catalyst particles. FIG. 5 is a graph showing a relationship between a ratio Wp / Wc of both compounding weights and a degree of dispersion D of catalyst particles. FIG. 6 is a graph showing the relationship between the degree of dispersion D of catalyst particles and the thickness of an air electrode and a fuel electrode. FIG. 7 is a graph showing a relationship between a combination of an air electrode and a fuel electrode and a terminal voltage. [Description of Signs] 1 solid polymer fuel cell 2 electrolyte membrane 3 air electrode 4 fuel electrode

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaaki Nanami 1-4-1, Chuo, Wako-shi, Saitama Pref. Inside of Honda R & D Co., Ltd. (72) Inventor Junji Matsuo 1-4-1, Chuo, Wako-shi, Saitama In Honda R & D Co., Ltd. (56) References JP-A-2001-185162 (JP, A) JP-A-2001-266901 (JP, A) JP-A-7-134995 (JP, A) JP-A 2001-160406 (JP, A) A) JP-A-11-339815 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 4/86-4/98 H01M 8/00-8/24

Claims (1)

(57) Claims 1. An electrolyte membrane (2) having an aromatic hydrocarbon-based polymer ion-exchange component, and an air electrode (3) and a fuel electrode () sandwiching the electrolyte membrane (2). 4) and wherein the air electrode (3) and the fuel electrode (4), respectively, a plurality of catalyst particles and polymer ion-exchange components obtained by supporting a catalytic metal on the surface of the carbon black particles,
The polymer ion exchange component is the aromatic hydrocarbon polymer
Aromatic hydrocarbon polymer ion exchange same as ion exchange component
Exchange components and different aromatic hydrocarbon polymer ion exchange
In the fuel electrode (4), the carbon black particles have a water adsorption amount A at a saturated steam pressure of 60 ° C. of A ≦ A.
80 cc / g, and when the blending weight of the polymer ion exchange component is Wp and the blending weight of the carbon black particles is Wc, the ratio Wp / Wc of the blending weights Wp and Wc is determined. Wc is 0.2 ≦ Wp / W
c ≦ 0.8, and in the air electrode (3), the carbon black particles have a water adsorption amount A at a saturated steam pressure of 60 ° C. A ≧ A
When the compounding weight of the polymer ion exchange component is Wp and the compounding weight of the carbon black particles is Wc, the hydrophilicity is 150 cc / g.
The ratio Wp / Wc of the two compound weights Wp, Wc is 0.6 ≦ Wp /
Wc ≦ 1.25, and humidifies only from the fuel electrode (4) side.