Disclosed are an electrode including a porous substrate, a membrane-electrode assembly for a fuel cell including the same and a method of manufacturing the same. In the method of manufacturing the membrane-electrode assembly, the amount of a catalyst that is loaded depending on the position is applied in a gradational manner, thus efficiently using the catalyst, thereby reducing costs owing to the use of a decreased amount of the metal catalyst. Further, the membrane-electrode assembly includes the electrode including a porous substrate, thus making it easy to select hot-pressing conditions and increasing processing efficiency. The porous substrate is hydrophobic and the pore size in the electrode is not decreased compared to conventional electrodes, thus reducing flooding and generating various operation regions. The electrode including the porous substrate can minimize electrode loss, thus improving electrode durability.

A positive electrode (10) for an air cell of the present invention includes: a catalyst layer (11) composed of a porous layer containing electrical conductive carbon (1), a binder (2), and a catalyst component (3); and a fluid-tight gas-permeable layer (12) composed of a porous layer containing an electrical conductive carbon (1a) and a binder (2). The fluid-tight gas-permeable layer is stacked on the catalyst layer. This configuration can facilitate series connection of the air cells while preventing electrolysis solution from leaking out of a positive electrode. It is therefore possible to enhance the manufacturing efficiency and handleability of the air cells.

A membrane electrode gas diffusion layer assembly for a fuel cell includes a membrane electrode assembly including an electrolyte membrane, an anode catalyst layer, and a cathode catalyst layer, an anode diffusion layer joined to the anode catalyst layer of the membrane electrode assembly, and a cathode diffusion layer joined to the cathode catalyst layer of the membrane electrode assembly, in which at least one of the anode diffusion layer and the cathode diffusion layer includes a microporous layer that makes contact with the membrane electrode assembly, the microporous layer contains a cerium compound, and at least one of the electrolyte membrane, the anode catalyst layer, and the cathode catalyst layer comprises cerium ions.

A method of manufacturing a cathode device includes providing a porous substrate and forming a nitrogen-doped graphene layer in the substrate.

The purpose of the present invention is to provide a carbon sheet that is suitably employed in a gas-diffusion-electrode substrate that has excellent flooding resistance and with which it is possible to suppress internal peeling of the carbon sheet. In order to achieve the aforementioned purpose, the present invention has the following configuration. Specifically, provided is a porous carbon sheet containing carbon fibers and a binder, wherein, in a section between a surface on one side of the carbon sheet and a surface on the other side thereof, when layers obtained by dividing, under compression, the carbon sheet into six equal parts in the thickness direction are, assumed to be layer 1, layer 2, layer 3, layer 4, layer 5, and layer 6, in order starting from the layer including the surface on the one side to the layer including the surface on the other side, the layer in which the packing ratio under compression is the greatest is layer 2, and the relationships of the packing ratios under compression among layer 2, layer 3, layer 4, layer 5, and layer 6 are such that layer 2 has the greatest packing ratio, and layer 3 has the second-greatest packing ratio.

A catalyst layer for a fuel cell, wherein the catalyst layer comprises a catalyst-supporting carbon and an ionomer; wherein, in a particle size distribution obtained by the laser diffraction/scattering method, the catalyst-supporting carbon has at least two aggregate particle size peaks at less than 1 ?m and at 1 ?m or more; wherein, when a thickness of the catalyst layer is divided into three equal parts, the catalyst layer has a first region on a gas diffusion layer side, a second region in a middle part, and a third region on an electrolyte membrane side; and wherein a void ratio V.sub.G of the first region is 5% or more higher than a void ratio V.sub.M of the third region.

Disclosed are a membrane-electrode assembly for fuel cells, a method of manufacturing the same and a fuel cell system containing the same. The membrane-electrode assembly for fuel cells includes an anode and a cathode facing each other, and a polymer electrolyte membrane interposed between the anode and the cathode, wherein at least one of the anode and the cathode further includes a porous support and a catalyst layer for fuel cells disposed on one surface of the porous support. The electrode of the membrane-electrode assembly is a free-standing electrode, and the electrode has excellent adhesivity to the polymer electrolyte membrane and thus can prevent performance deterioration resulting from detachment of the electrode from the polymer electrolyte membrane during operation of fuel cells, and in particular, can secure high durability since the electrode is not readily detached even under harsh operation environments.

The present invention provides a gas diffusion layer for a fuel cell that is balanced between performance and durability. The present invention provides a gas diffusion electrode having a microporous layer, wherein the microporous layer has at least a first microporous layer and a second microporous layer, the first microporous layer has a cross-sectional F/C ratio of 0.06 or more and 0.33 or less, the second microporous layer has a cross-sectional F/C ratio less than 0.06, and wherein the first microporous layer is equally divided into a part not in contact with the second microporous layer and a part in contact with the second microporous layer, in the equally divided first microporous layer. The part not in contact with the second microporous layer is referred to as a microporous layer 1-1, the part in contact with the second microporous layer is referred to as a microporous layer 1-2, and the microporous layer 1-1 has a cross-sectional F/C ratio smaller than that of the microporous layer 1-2, wherein F is the mass of fluorine atoms, C is the mass of carbon atoms, and the cross-sectional F/C ratio is the value of mass of fluorine atoms/mass of carbon atoms as measured in the cross-sectional direction.

A fuel cell electrode includes a substrate having a first surface and a second surface, a passage channel connecting the first surface and the second surface, and a nitrogen-doped graphene layer disposed within the passage channel. The passage channel is formed of a plurality of pores connected to each other.

A layered structure for a fuel cell comprises a carbon-based catalyst-free gas diffusion layer substrate and a carbon-based microporous layer, which is joined to the gas diffusion layer substrate and comprises a plurality of carbon carriers or carbon fibers embedded into an ion-conducting polymer binder mixture. The polymer binder mixture comprises a sulfur-free binding polymer and a sulfonated polymer, and a fraction of the binding polymer at or near a surface of the microporous layer facing away from the gas diffusion layer substrate is less than or equal to a fraction of the sulfonated polymer. A method for producing a layered structure of this type is also provided.