JP4511911B2 - Electrode for polymer electrolyte fuel cell - Google Patents

Description

  The present invention relates to an electrode for a polymer electrolyte fuel cell.

  The polymer electrolyte fuel cell is being developed as a clean power source using hydrogen as a fuel, a driving power source for an electric vehicle, and a stationary power source using both power generation and heat supply. In addition, solid polymer fuel cells are characterized by high energy density compared to secondary batteries such as lithium ion batteries, and are being developed as power sources for portable computers or mobile communication devices.

  The power supply portion of the polymer electrolyte fuel cell is composed of an anode (fuel electrode) and a cathode (air electrode), and a proton exchangeable solid polymer electrolyte membrane disposed between both electrodes. The anode and the cathode are a mixed thin film of a catalyst supporting a noble metal such as platinum, a pore-forming agent such as fluororesin powder, and a solid polymer electrolyte.

  In the polymer electrolyte fuel cell, a high output per unit electrode area is required, and accordingly, the electrochemical reaction activity of the electrode catalyst constituting the anode and the cathode is required to be high. Here, the electrochemical reaction activity is an electrochemical activity that oxidizes hydrogen to hydrogen ions at the anode using hydrogen as a fuel, and an electrochemical activity that reduces oxygen to water at the cathode. Reaction activity. A noble metal such as platinum is used for the anode and cathode electrode catalyst of such a polymer electrolyte fuel cell. Reduction of the amount of expensive noble metal used per unit area of the electrode and high electrochemical activity are required.

  In the polymer electrolyte fuel cell, mass transfer such as gas diffusion and hydrogen ion transfer in the anode and cathode catalyst layers greatly affects the electrochemical reaction rate on the electrode catalyst surface, that is, the output of the fuel cell. Further, in the polymer electrolyte fuel cell, there are water supplied to increase proton conductivity of the polymer electrolyte membrane and water generated at the cathode, but when the water vapor in the catalyst layer becomes supersaturated, These water aggregate to form droplets, blocking the gas diffusion path, leading to insufficient gas supply, and causing an extreme voltage drop (this phenomenon is called flooding). From the above, when hydrogen is used as fuel, diffusion of hydrogen gas in the electrode at the anode, movement of the generated hydrogen ions from the anode through the electrolyte membrane to the surface of the cathode catalyst particles, and further, in the cathode, in the oxygen electrode Diffusion and generated water discharge must be done efficiently.

As a method to improve the utilization efficiency of the electrode catalyst and reduce the amount of noble metal used, Patent Document 1 supports noble metal using carbon black with a volume of 0.5 cm ³ / g or less occupied by pores having a diameter of 8 nm or less as a support. Thus, there is described a method for controlling the adsorption of the catalyst metal particles to the support pores where the polymer electrolyte, which is the migration path of hydrogen ions, cannot be distributed. Patent Document 2 describes that carbon black whose pores having a diameter of 6 nm or less that cannot be penetrated by the polymer solid electrolyte are 20% or less of all pores is used as a carrier.

As a method for improving the diffusibility of the reaction gas to the electrode catalyst surface, for example, Patent Document 3 discloses that the specific surface area by the BET method is 250 to 400 m ² / g, the primary particle diameter is 10 to 17 nm, and the surface is open. It is described that carbon black having a total volume of pores having a radius of 10 to 30 nm and 0.40 to 2.3 cm ³ / g is used as a catalyst support.

Furthermore, in order to reduce the amount of noble metal used, Patent Document 2 discloses a method for forming an electrode having noble metal particles supported in a highly dispersed state and having excellent gas diffusibility. It describes that a noble metal is supported on carbon fine powder having 20% or less of the pores, DBP oil absorption of 200 to 495 mL / 100 g, and specific surface area of 300 to 1270 m ² / g.

Japanese Patent Laid-Open No. 9-16622 JP 2000-100448 JP 2003-201417

To spread the polymer electrolyte fuel cell, a noble metal usage in electrocatalyst 0.1 mg / cm ² or less, desirably is it said it is necessary to below 0.03 mg / cm ^2. For this purpose, not only to reduce the pores that cannot penetrate the polymer solid electrolyte and increase the utilization rate of the platinum catalyst, but also to further refine the platinum fine particles and improve the utilization rate of the platinum catalyst. A means for changing the distribution state of the solid polymer electrolyte is required. Moreover, in order to improve gas diffusivity, it is necessary to control the voids in the carbon material more than ever.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems, to increase the utilization efficiency of platinum, and to provide a polymer electrolyte fuel cell electrode excellent in gas diffusibility.

  In order to solve the above-mentioned problems, the present inventors diligently studied various types of carbon powders as an electrode catalyst carrier, and the present invention has a high-density dispersion of noble metal catalysts, particularly platinum fine particles, and is excellent in gas diffusibility. The solid polymer fuel cell electrode was obtained.

That is, the present invention is as follows.
(1) A polymer electrolyte fuel cell electrode formed from a gas diffusion layer containing a fibrous carbon material, a catalyst component formed on one side of the gas diffusion layer, and a catalyst layer containing a carbon material and an electrolyte material. of the carbon material include, 2 nm or less of the pore volume of the catalyst supporting carbon material carrying the catalyst Ri der least 0.1 mL / g, the gas diffusion layer and the catalyst layer of the electrode for a polymer electrolyte fuel cell In the carbon black of the micropore layer, the water vapor adsorption amount at 25 ° C. and 90% relative humidity is 100 mL / g or less and the DBP oil absorption amount X (mL / 100 g) and nitrogen adsorption specific surface area Y (m ² / g) of the X / Y ratio is a solid polymer fuel cell electrode, characterized in der Rukoto 1 or more.
(2) The electrode for a solid polymer fuel cell according to (1), wherein a specific surface area of the catalyst support carbon material contained in the catalyst layer is 500 m ² / g or more by BET method.
(3) The solid polymer fuel cell electrode according to (1) or (2), wherein the DBP oil absorption amount of the catalyst support carbon material contained in the catalyst layer is 300 mL / 100 g or more .

  The electrode for a solid polymer fuel cell of the present invention has a high utilization rate of platinum, excellent gas diffusibility, and exhibits extremely excellent battery performance by controlling the affinity between the carbon support and the solid polymer electrolyte. be able to.

  The electrode for a polymer electrolyte fuel cell of the present invention comprises two layers of a gas diffusion layer and a catalyst layer, or three layers of a gas diffusion layer, a micropore layer, and a catalyst layer.

  The properties required for the gas diffusion layer are good gas permeability and electron conductivity, but the reason why the fibrous carbon material was selected as the main component is that it has a good pore size while easily diffusing gas. This is because the material is suitable for having electron conductivity.

  In the present invention, the fibrous carbon material is the main component of the gas diffusion fiber layer, and is reinforced with a binder such as a polymer material for the purpose of increasing the mechanical strength, and is further carbonized and used. The second and third components may be combined. Furthermore, the fibrous carbon material can be used with appropriate surface characteristics by coating the surface of the fibrous carbon material with a fluororesin, a surfactant, a silane coupling agent, or the like. Alternatively, the fibrous carbon material can be heat treated under an inert atmosphere to provide suitable surface properties. Examples of the coating method include a method in which a liquid in which a fluororesin emulsion or a pulverized fluororesin is dispersed or a liquid containing a silane coupling agent is applied to the gas diffusion fiber layer by contact, dipping, spraying, etc., and then dried. It is done. In the case of a fluororesin, the coating can be made uniform by raising the temperature to the melting point or higher after drying and melting or softening.

  The catalyst layer contains a catalyst component, a carbon material, and an electrolyte material as main components.

  The carbon material contained in the catalyst layer of the present invention is more preferably divided into a catalyst carrier carbon material and a gas diffusion carbon material. By including a carbon material in which the catalyst component is not supported, that is, a gas diffusion carbon material, in the catalyst layer, it is possible to develop a path through which the gas can diffuse into the catalyst layer. In the case of a main mixed gas or cathode, oxygen or air easily diffuses into the catalyst layer and can come into contact with many catalyst surfaces. Therefore, the reaction in the catalyst layer is efficiently advanced, and high battery performance can be obtained.

  On the other hand, the catalyst support carbon material contained in the catalyst layer preferably has a pore volume of 2 nm or less of 0.1 mL / g or more, and more preferably 0.3 mL / g or more. This is because extremely fine pores of 2 nm or less function as adsorption sites for the noble metal fine particles, which is a necessary condition for high dispersion of the noble metal fine particles. When the pore volume is less than 0.1 mL / g, the precious metal fine particles are uniform with a particle diameter of about 2 nm if the ratio of platinum in the catalyst layer to platinum contained in the catalyst layer is 20% by mass or less. Although there are carbon materials that can be dispersed in the catalyst, if the ratio of the catalyst component exceeds 20% by mass, it becomes difficult to uniformly and highly disperse the noble metal fine particles. However, the pore volume of 2 nm or less is usually 2 mL / g or less, and it is difficult to obtain a carbon material exceeding this.

  Furthermore, the function of ultrafine pores of 2 nm or less includes the effect of increasing the affinity with the electrolyte material. In order to function efficiently as a fuel cell, it is necessary to create a number of places where three parts come into contact: a catalyst that causes hydrogen oxidation or oxygen reduction, a carbon material that contributes to electron conduction, and an electrolyte material that contributes to proton conduction. is necessary. This is because protons and electrons generated by hydrogen oxidation are not used effectively unless an electrolyte material and an electron-conducting carbon material exist in the vicinity, respectively, and oxygen reduction can only occur at three points. . When the volume of ultrafine pores of 2 nm or less is 0.1 mL / g or more, the affinity with the electrolyte material increases, and the electrolyte material spreads evenly on the surface of the catalyst support carbon material, thus increasing the utilization rate of platinum. It becomes possible. On the other hand, when the volume of pores of 2 nm or less is less than 0.1 mL / g, the electrolyte material does not spread uniformly on the surface of the catalyst support carbon material, so that the platinum fine particles are highly dispersed on the surface of the catalyst support carbon material. Even so, platinum particles that are effectively used are limited, and as a result, an efficient battery cannot be obtained.

Similarly, in order to uniformly and highly disperse the noble metal fine particles with a particle diameter of about 2 nm, the specific surface area by the BET method of the catalyst support carbon material contained in the catalyst layer is preferably 500 m ² / g or more, 800 m ² / g or more is desirable. However, the specific surface area by the BET method is usually 2500 m ² / g or less, and it is difficult to obtain a carbon material exceeding this.

  DBP oil absorption is the amount of dibutyl phthalate absorbed by the carbon material when the unit mass carbon material is contacted with dibutyl phthalate, and is mainly absorbed in the gaps between the primary particles. When a plurality of primary particles are fused and a secondary structure called a structure is developed, the DBP oil absorption increases, and when the structure is not so developed, the DBP oil absorption tends to decrease. By developing the structure, a network for gas diffusion and removal of generated water is generated, and flooding hardly occurs even when a high current is taken out. For this purpose, the DBP oil absorption amount of the catalyst support carbon material is preferably 300 mL / 100 g or more, and more preferably 400 mL / 100 g or more. However, the DBP oil absorption is usually 700 mL / 100 g or less, and it is difficult to obtain a carbon material exceeding this.

  The catalyst component contained in the catalyst layer preferably contains at least platinum, and among the platinum and the catalyst support carbon material, the ratio of platinum is preferably 20% by mass or more and 80% by mass or less. Within this range, at least the fuel cell can function, and more preferably 20% by mass to 60% by mass. Outside this range, for example, less than 20% by mass, the catalyst component supported on the catalyst-supporting carbon material decreases, and the output per unit thickness of the catalyst layer decreases. Therefore, in order to obtain a high output, it is necessary to thicken the catalyst layer, and it becomes difficult to remove the generated water. On the other hand, if it exceeds 80% by mass, it becomes difficult to disperse the platinum fine particles at a high density, the particle diameter of the platinum fine particles becomes large, and platinum cannot be used effectively.

  In addition to platinum, the catalyst component can further contain one or more metal elements selected from iron, cobalt, nickel, copper, and ruthenium. These metals may be a complex with platinum or an alloy. Furthermore, it may be a complex of these metals with an organic compound or an inorganic compound.

  The reason why the micropore layer is disposed between the gas diffusion layer and the catalyst layer is that the gas diffusion fiber layer of the present invention has a large pore size, so that the structure is rough, so that it directly contacts the catalyst layer having a micro structure. In the structure, when the cells are assembled, there are few contact sites between the gas diffusion fiber layer and the catalyst layer, or the surface pressure applied to the catalyst layer is roughly distributed. For example, the electron conduction resistance or gas in the catalyst layer This is because it leads to a distribution of diffusivity and further reactivity, and as a result, there is a high possibility that the performance as a battery is not sufficiently exhibited. In other words, the micropore layer has a more micro structure, preferably the same structural scale as the catalyst layer, and cancels the roughness of the structure of the gas diffusion fiber layer with a material that does not impair gas diffusibility and electronic conductivity. If it can be connected to the catalyst layer, the reaction distribution in the catalyst layer can be suppressed, and the battery performance can be sufficiently exhibited.

  Carbon black is used as a main component in the micropore layer of the present invention. The primary reason carbon black is used is that it has the same structural scale as the catalyst layer, has excellent electronic conductivity, and has appropriate surface characteristics depending on the type, so that the gas diffusion path is blocked by water. This is because it can be effectively prevented.

  Such carbon black can be selected using the water vapor adsorption amount as an index. Specifically, if the water vapor adsorption amount of carbon black at 25 ° C. and a relative humidity of 90% is 100 mL / g or less, for example, it is possible to suppress clogging of the gas diffusion path due to water generated during large current discharge on the cathode side, A current can be taken out with a stable voltage. If it is more than 100 mL / g, the condensed water stays in the micropore layer at the time of current discharge, the gas diffusion path is likely to be blocked, and the voltage behavior tends to become unstable.

  In order to obtain a higher effect, it is necessary to select carbon black having a water vapor adsorption amount of 1 mL / g or more and 50 mL / g or less at 25 ° C. and a relative humidity of 90%. Within this range, it is possible to prevent the electrolyte material in the cathode from being dried and maintain a suitable wet state even during a small current discharge with a small amount of water generated inside the cathode. Since water generated inside the layer can be efficiently discharged out of the electrode and a gas diffusion path can be secured, an efficient battery can be obtained over the entire region regardless of load conditions from low load to high load. In addition, if the carbon material has a water vapor adsorption amount of 1 mL / g or more and 50 mL / g or less at 25 ° C. and 90% relative humidity, it can be used as a gas diffusion carbon material by mixing two or more types of carbon materials. it can. If the amount of water vapor adsorption at 25 ° C and 90% relative humidity is less than 1 mL / g, the water repellency becomes too strong and it is difficult to obtain the effect of humidifying from the outside of the cell. It is difficult to maintain a wet state, and proton conductivity may be reduced. If the amount of water vapor adsorbed at 25 ° C and 90% relative humidity exceeds 50 mL / g, when a large current is continuously taken out, water generated inside the catalyst layer cannot catch up, blocking the gas diffusion path. There is a risk that.

  Here, the amount of water vapor adsorbed at 25 ° C. and 90% relative humidity, which is an index in the present invention, represents the amount of water adsorbed per 1 g of carbon material placed in an environment of 25 ° C. converted into a water vapor volume in a standard state. It was. The measurement of the amount of water vapor adsorption at 25 ° C. and a relative humidity of 90% can be performed using a commercially available water vapor adsorption amount measuring device. Alternatively, dry carbon black having a known mass can be allowed to stand in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 90% for a sufficient period of time, and the change can be measured from the mass change.

  The second reason why carbon black is used for the micropore layer of the present invention is the three-dimensional structure of carbon black. In carbon black, a plurality of primary particles are fused to form a secondary structure called a structure. Depending on the type, this structure has developed, and the network of primary particles has a structure that encloses space. In the micropore layer, a gas diffusion path surrounded by a network of primary particles can be formed by connecting such spaces. The gas diffusion path formed in this way is not easily broken even when the cell is strongly fastened, and it is easy to maintain the hole diameter when the micropore layer is formed over a long period of time. Further, if the type of carbon black is determined using the structure as an index, the hole diameter of the gas diffusion path formed in the micropore layer is determined, so there is an advantage that control is easy.

  In the micropore layer of the present invention, carbon black having a higher structure is preferably used as a main component. This is because if the structure is low, formation of a gas diffusion path by the structure cannot be expected. The degree of structure can be determined by observing with an electron microscope, but can be determined by the relationship between DBP oil absorption and specific surface area.

  DBP oil absorption is the amount of dibutyl phthalate absorbed by carbon black when unitary carbon black is brought into contact with dibutyl phthalate, and is mainly absorbed in the gaps between primary particles. When the structure is developed, the DBP oil absorption increases, and when the structure is not so developed, the DBP oil absorption tends to decrease. However, DBP is absorbed not only by the gaps between the primary particles but also by the fine pores formed inside the primary particles, so that the DBP oil absorption amount does not necessarily represent the structure level. This is because when the specific surface area as measured by the nitrogen adsorption amount increases, the DBP absorbed in the micropores increases, and the total DBP oil absorption increases. Therefore, in the high structure carbon black, the DBP oil absorption amount increases with respect to the nitrogen adsorption amount, and conversely, in the low structure carbon black, the DBP hot water absorption amount decreases relative to the nitrogen adsorption amount.

Preferably, when carbon black having a ratio X / Y of DBP oil absorption X (mL / 100 g) and nitrogen adsorption specific surface area Y (m ² / g) of 1 or more is used, a micropore layer having a preferable gas diffusion path Can be formed. This is because when the X / Y ratio is 1 or more, the structure is large and a gas diffusion path can be expected to be formed by the structure. If the ratio of X / Y is less than 1, formation of a gas diffusion path due to the structure cannot be expected, and the gap between the carbon black secondary particles mainly forms a gas diffusion path. If it cannot be ensured or the holes are easily broken when the cells are fastened, it is difficult to control and it may be difficult to bring out the performance of the catalyst layer stably. More preferably, the X / Y ratio is 1.5 or more. If it is 1.5 or more, the network of gas diffusion paths due to the structure is sufficiently developed, and flooding becomes difficult even when a high current is taken out. With such a structure, gas easily diffuses, and it is difficult to block the gas diffusion path by water, so that the original performance of the catalyst layer is easily extracted. However, the ratio of X / Y is usually 5 or less, and it is difficult to obtain a carbon material exceeding this ratio.

[Example 1]
In this example, carbon materials having different pore volumes, nitrogen adsorption specific surface areas, DBP oil absorption amounts, and water vapor adsorption amounts were used as catalyst carriers, including comparative examples. Table 1 shows the pore volume, nitrogen adsorption specific surface area Y (m ² / g), DBP oil absorption X (mL / 100 g), X / Y, and water vapor adsorption of the carbon material used.

  Nitrogen adsorption specific surface area was measured with nitrogen gas using an automatic specific surface area measurement device (Nippon Bell, BELSORP36) after vacuum drying at 120 ° C, and the specific surface area was determined by a one-point method based on the BET method. . For the evaluation of the pores, t-plot analysis (adsorption amount was plotted against the average thickness t of the adsorption film) was used. In the t-plot, the gradient becomes smaller at t = 1 nm or more where the adsorption to the pores of 2 nm or less is completed compared to t = 1 nm or less. The pore volume with a diameter of 2 nm or less was determined from the adsorption amount obtained by extrapolating the straight line of the high t region to t = 0.

  The DBP oil absorption amount was determined by converting the DBP addition amount at 70% of the maximum torque into the DBP oil absorption amount per 100 g of sample using an absorber meter (manufactured by Brabender).

  The amount of water vapor adsorption was measured using a constant capacity water vapor adsorption device (Nippon Bell, BELSORP18). From the vacuum state to the saturated vapor pressure of water vapor at 25 ° C., water vapor was gradually supplied to gradually change the relative humidity, and the water vapor adsorption amount was measured. An adsorption isotherm was drawn from the obtained measurement results, and the water vapor adsorption amount at a relative humidity of 90% was read from the figure. In Table 1, the read water vapor amount is shown in terms of the water vapor volume in the standard state adsorbed per 1 g of the sample.

Using the above carbon material as a catalyst carrier, a polymer electrolyte fuel cell electrode was produced by the following method. The carbon materials shown in Table 1 were dispersed in water as catalyst support carbon materials, respectively, kept at 50 ° C., and a chloroplatinic acid aqueous solution and a formaldehyde aqueous solution were added with stirring to obtain a catalyst precursor. The catalyst precursor was filtered, washed with water and dried, and then subjected to a reduction treatment in a 100% H ₂ stream at 300 ° C. for 3 hours to produce a platinum catalyst in which 20% by mass of platinum was supported on the catalyst support carbon material.

  Table 2 shows the crystallite diameter of the obtained platinum catalyst. The crystallite diameter was estimated using the Scherrer method from the half-value width of the (111) peak of platinum obtained by an X-ray diffractometer (manufactured by Rigaku Corporation, RAD-3C). As shown in Table 2, the carbon materials A, G, and K have a very large crystallite diameter, and it is expected that the performance as a polymer electrolyte fuel cell electrode is not so high.

  Add 12 types of these catalysts in an argon stream to a 5% Nafion solution (Aldrich) so that the mass of Nafion solids is twice the mass of the platinum catalyst. Then, butyl acetate was added with stirring so that the solid content concentration of the platinum catalyst and Nafion was 6% by mass to prepare 12 types of catalyst slurry. In a separate container, the carbon material A shown in Table 1 was taken, butyl acetate was added so that the carbon material was 6% by mass, and the carbon material was pulverized with ultrasound to prepare a carbon material slurry. Each of the 12 types of catalyst slurry prepared above and the carbon material slurry were mixed at a mass ratio of 8: 2, and then sufficiently stirred to prepare 12 types of catalyst layer slurry.

  After preparing a commercially available carbon cloth (EC-CC1-060 manufactured by ElectroChem), dipping it in a Teflon dispersion diluted to 5%, drying it, and further raising the temperature to 340 ° C. in an argon stream, A gas diffusion layer was produced.

12 types of catalyst layer slurries are applied to one side of the gas diffusion layer by spraying, dried in an argon stream at 80 ° C. for 1 hour, and a solid polymer type containing carbon materials A to L as catalyst-supporting carbon materials in the catalyst layer 12 types of fuel cell electrodes were obtained. In addition, conditions, such as spray, were set so that each electrode might use platinum usage amount 0.10 mg / cm < ² >. The amount of platinum used was determined by measuring the dry mass of the electrode before and after spray coating and calculating the difference.

  In addition, two pieces of 2.5 cm square were cut from the obtained polymer electrolyte fuel cell electrode, and the electrolyte membrane (Nafion 112) with two electrodes of the same type so that the catalyst layer was in contact with the electrolyte membrane. Then, hot pressing was performed at 130 ° C. and a total pressure of 0.625 t for 3 minutes to produce 12 types of MEA.

  Each of the obtained MEA 12 species was incorporated into a fuel cell measurement device, and the cell performance was measured. For battery performance measurement, the voltage between the cell terminals was changed stepwise from the open voltage (usually about 0.9 to 1.0V) to 0.2V, and the current density flowing when the cell terminal voltage was 0.8V and 0.5V was measured respectively. . The gas was supplied to the cathode with air and pure hydrogen to the anode so that the utilization rates would be 50% and 80%, respectively, and each gas pressure was adjusted to 0.1 MPa with a back pressure valve provided downstream of the cell. . The cell temperature was set at 80 ° C., and the supplied air and pure hydrogen were bubbled in distilled water kept at 80 ° C. and 90 ° C., respectively, and humidified.

Table 3 shows the battery performance results of MEA12. MEA 2, 3, 4, 5, and 12 of the present invention exhibited excellent battery characteristics as compared with other comparative examples. Among them, a carbon material L having a pore volume of 2 nm or less of 0.3 mL / g or more, a nitrogen adsorption specific surface area of 800 m ² / g or more, and a DBP oil absorption of 400 mL / g or more is used. The MEA2 had excellent characteristics of both 0.8V and 0.5V.

[Example 2]
Prepare carbon cloth (Electro-Chem EC-CC1-060), soak it in a Teflon dispersion diluted to 5%, dry it, and then heat it up to 340 ° C in an argon stream and gas diffusion fiber A layer was made. Further, 99 g of ethanol was added to 1 g of each of the carbon materials A, B, D, F, and K, and the carbon material was pulverized with a ball mill to form a primary dispersion. Thereafter, 0.833 g of 30% Teflon dispersion was dropped little by little while stirring the primary dispersion to prepare a micropore layer slurry. The slurry was applied to one side of the previously prepared gas diffusion fiber layer using a spray, dried at 80 ° C. in an argon stream, then heated to 340 ° C., and the gas diffusion fiber layer and the micropore layer were laminated. Five types of gas diffusion layers were prepared.

  A platinum catalyst was produced under the same conditions as in Example 1 using the carbon material L as the catalyst support. Further, using this platinum catalyst, a catalyst layer slurry was produced under the same conditions as in Example 1. This catalyst layer slurry was applied onto the above-mentioned five gas diffusion layers by spraying and then dried under the same conditions as in Example 1 to obtain five types of polymer electrolyte fuel cell electrodes. Further, using these 5 types of solid polymer type fuel cell electrodes, hot pressing was performed under the same conditions as in Example 1 to prepare 5 types of MEA.

  The obtained MEA 5 species were subjected to battery performance measurement under the same conditions as in Example 1.

  Table 4 shows the battery performance results of the obtained MEA5 types. As a result, MEA13, 16, and 17 of the present invention showed superior battery characteristics compared to MEA14 and 15. Among them, a water vapor adsorption amount of 50 mL / g or less, and a carbon material A having a ratio X / Y of DBP oil absorption amount X and nitrogen adsorption specific surface area Y of 1.5 or more, MEA 13 using K as a micropore layer, 17 exhibited extremely good battery performance.

Claims (3)

An electrode for a polymer electrolyte fuel cell formed from a gas diffusion layer containing a fibrous carbon material, a catalyst component formed on one side thereof, and a catalyst layer containing a carbon material and an electrolyte material, the carbon contained in the catalyst layer among materials, 2 nm or less of the pore volume of the catalyst supporting carbon material carrying the catalyst Ri der least 0.1 mL / g, while the gas diffusion layer and the catalyst layer of the electrode for a polymer electrolyte fuel cell It has a micropore layer containing carbon black, the water vapor adsorption amount at 25 ° C. and 90% relative humidity of the carbon black of the micropore layer is 100 mL / g or less, and DBP oil absorption amount X (mL / 100 g) solid polymer fuel cell electrode X / Y ratio of a nitrogen adsorption specific surface area Y (m ² / g) is characterized in der Rukoto 1 or more. ^{2. The} electrode for a solid polymer fuel cell according to claim 1, wherein the specific surface area by the BET method of the catalyst support carbon material contained in the catalyst layer is 500 m ² / g or more. 3. The polymer electrolyte fuel cell electrode according to claim 1, wherein the catalyst support carbon material contained in the catalyst layer has a DBP oil absorption of 300 mL / 100 g or more .