Abstract: There is provided a method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane. The electrode catalyst layer formed in the membrane electrode assembly is produced by a drying process that dries a catalyst ink which includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer, at a predetermined temperature. The catalyst ink includes a plurality of different solvents having different boiling points. The predetermined temperature is set to be lower than the boiling point of the solvent having the lowest boiling point among the plurality of different solvents.

Abstract: There is provided a method of manufacturing an electrode catalyst layer for fuel cell. This manufacturing method comprises: (a) separating an ionomer solution by centrifugation into a supernatant that includes only an ionomer as a low molecular-weight component in the ionomer solution and a sediment including an ionomer as a high molecular-weight component having a higher molecular weight than that of the low molecular-weight component included in the supernatant; (b) using the ionomer included in the sediment as an ionomer for electrode catalyst layer and producing a catalyst ink that includes catalyst-supported particles with a catalyst metal supported thereon, a solvent and the ionomer for electrode catalyst layer; and (c) using the catalyst ink to form an electrode catalyst layer.

Abstract: The method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane comprises (a) producing an electrode catalyst layer by drying a catalyst ink that includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer; and (b) selecting a produced electrode catalyst layer that contains an amount of sulfate ion equal to or less than a specified reference value, and manufacturing the membrane electrode assembly by using the selected electrode catalyst layer.

Abstract: An object is to prevent an increase in overall thickness of a membrane electrode assembly. There is provided a membrane electrode assembly. The membrane electrode assembly comprises an electrolyte membrane; a catalyst layer that is formed on a surface of the electrolyte membrane and includes a catalyst and an ionomer; and a gas diffusion layer that is formed on a surface of the catalyst layer on an opposite side to the electrolyte membrane. The catalyst layer includes a first layer that is in contact with the electrolyte membrane and a second layer that is in contact with the gas diffusion layer. An amount of the ionomer in a first portion of the first layer that is in contact with the electrolyte membrane is larger than an amount of the ionomer in a second portion of the first layer that is in contact with the second layer. An amount of the ionomer in a third portion of the second layer that is in contact with the gas diffusion layer is larger than the amount of the ionomer in the first portion.

Abstract: An object is to prevent an increase in overall thickness of a membrane electrode assembly. There is provided a membrane electrode assembly. The membrane electrode assembly comprises an electrolyte membrane; a catalyst layer that is formed on a surface of the electrolyte membrane and includes a catalyst and an ionomer; and a gas diffusion layer that is formed on a surface of the catalyst layer on an opposite side to the electrolyte membrane. The catalyst layer includes a first layer that is in contact with the electrolyte membrane and a second layer that is in contact with the gas diffusion layer. An amount of the ionomer in a first portion of the first layer that is in contact with the electrolyte membrane is larger than an amount of the ionomer in a second portion of the first layer that is in contact with the second layer. An amount of the ionomer in a third portion of the second layer that is in contact with the gas diffusion layer is larger than the amount of the ionomer in the first portion.

Abstract: The method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane comprises (a) producing an electrode catalyst layer by drying a catalyst ink that includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer; and (b) selecting a produced electrode catalyst layer that contains an amount of sulfate ion equal to or less than a specified reference value, and manufacturing the membrane electrode assembly by using the selected electrode catalyst layer.

Abstract: There is provided a method of manufacturing a membrane electrode assembly that has an electrode catalyst layer formed on a surface of an electrolyte membrane. The electrode catalyst layer formed in the membrane electrode assembly is produced by a drying process that dries a catalyst ink which includes catalyst-supported particles having a catalyst metal supported thereon, a solvent and an ionomer, at a predetermined temperature. The catalyst ink includes a plurality of different solvents having different boiling points. The predetermined temperature is set to be lower than the boiling point of the solvent having the lowest boiling point among the plurality of different solvents.

Abstract: There is provided a method of manufacturing an electrode catalyst layer for fuel cell. This manufacturing method comprises: (a) separating an ionomer solution by centrifugation into a supernatant that includes only an ionomer as a low molecular-weight component in the ionomer solution and a sediment including an ionomer as a high molecular-weight component having a higher molecular weight than that of the low molecular-weight component included in the supernatant; (b) using the ionomer included in the sediment as an ionomer for electrode catalyst layer and producing a catalyst ink that includes catalyst-supported particles with a catalyst metal supported thereon, a solvent and the ionomer for electrode catalyst layer; and (c) using the catalyst ink to form an electrode catalyst layer.