Abstract: A method of producing a membrane electrode assembly including an electrolyte film, including: a process of obtaining a membrane body by forming an electrolyte resin precursor which is a precursor of an electrolyte resin used in the electrolyte film into a film form; and a hydrolysis process of obtaining the electrolyte film by hydrolyzing the membrane body, wherein the hydrolysis process includes a process of passing the membrane body through a first tank in which an alkaline aqueous solution is accommodated and a process of passing the membrane body through second tanks in which an aqueous solution in which a water-soluble hydroxy radical elimination accelerator is dissolved in advance is accommodated after the membrane body is passed through the first tank.

Abstract: An electrode catalyst layer for a fuel cell includes a first region and a second region more highly water repellent than the first region. The amount of catalyst per unit area in the first region is smaller than the amount of catalyst per unit area in the second region. The electrode catalyst layer makes it possible to reduce the amount of catalyst contained in the electrode catalyst layers, while avoiding a drop in output voltage of the fuel cell.

Abstract: A fuel cell includes an electrolyte membrane, a cathode electrode layer disposed at a surface of the electrolyte membrane, and an anode electrode layer disposed at a surface of the electrolyte membrane opposite to a surface facing the cathode electrode layer. At least one of the cathode electrode layer and the anode electrode layer includes a first catalyst layer disposed at an interface with the electrolyte membrane, and a second catalyst layer disposed at a surface of the first catalyst layer opposite to a surface facing the electrolyte membrane. The first catalyst layer is configured to contain a catalyst not supported on a carrier and not to contain a catalyst supported on a carrier. The second catalyst layer is configured to contain a catalyst supported on a carrier.

Abstract: Disclosed is a fuel cell wherein deterioration of fuel cell performance due to dry up phenomenon and flooding phenomenon is suppressed. Specifically disclosed is an assembly for fuel cells or a fuel cell wherein a catalyst layer contains a first composite catalyst particle containing a catalyst supporting particle and a solid polymer electrolyte and a second composite catalyst particle having a larger volume average particle diameter than the first composite catalyst particle and arrangement of the first composite catalyst particle and the second composite catalyst particle is controlled in the thickness direction of the catalyst layer. Consequently, deterioration of fuel cell performance due to dry up phenomenon or flooding phenomenon can be suppressed, thereby realizing a fuel cell with high efficiency.

Abstract: In an apparatus A in which electrode powder 10 is allowed to adhere via the electrostatic force to an electrolyte membrane that serves as a substrate 2 so as to form a catalyst layer, a screen 5 is held in a state of non-contact with the substrate 2, and a voltage is applied therebetween. The electrode powder 10 is allowed to adhere to an elastic feed roller 7, and the feed roller 7 is allowed to rotate in contact with the screen 5 by pressure. The electrode powder 10 is dispersed toward the substrate 2 so as to stably adhere thereto via both the electrostatic force and the extruding force of the elastic body. Variation of thickness and collapse of the outline are extremely reduced on the catalyst layer to be transferred and formed on the substrate (electrolyte membrane) via the electrostatic force using a conventionally used mesh-like screen so as to obtain a membrane electrode assembly with a high product manufacturing accuracy.

Abstract: A catalyst powder production method for constructing a catalyst layer in a fuel cell includes: forming a mixture that contains an electrolyte, a pore-forming material, and a catalyst-supporting particle that supports a catalyst; producing a composite powder in which the catalyst-supporting particle and the electrolyte are attached to a periphery of the pore-forming material by using the mixture; and producing the catalyst powder in the form of hollow particle by removing the pore-forming material from the composite powder.

Abstract: The battery performance of a solid polymer fuel cell is enhanced by improving a three-phase interface. A catalyst carrier conductive material 10, solid polymer electrolyte 20 and 30, and a good solvent and a poor solvent with respect to the solid polymer electrolyte are mixed so as to prepare an ink in which at least part of the solid polymer electrolyte is colloidalized. The ink is then dried to produce a powder catalytic material 40, which is applied to an electrolyte membrane or a gas diffusion layer, thereby forming a catalyst layer of an electrode.

Abstract: In an apparatus A in which electrode powder 10 is allowed to adhere via the electrostatic force to an electrolyte membrane that serves as a substrate 2 so as to form a catalyst layer, a screen 5 is held in a state of non-contact with the substrate 2, and a voltage is applied therebetween. The electrode powder 10 is allowed to adhere to an elastic feed roller 7, and the feed roller 7 is allowed to rotate in contact with the screen 5 by pressure. The electrode powder 10 is dispersed toward the substrate 2 so as to stably adhere thereto via both the electrostatic force and the extruding force of the elastic body. Variation of thickness and collapse of the outline are extremely reduced on the catalyst layer to be transferred and formed on the substrate (electrolyte membrane) via the electrostatic force using a conventionally used mesh-like screen so as to obtain a membrane electrode assembly with a high product manufacturing accuracy.