A porous carbon sheet contains carbon fiber and a binder, wherein the carbon sheet is characterized in that in a section from a plane having a 50% filling ratio closest to one surface to a plane having a 50% filling ratio closest to the other surface, when letting layer X be a layer with the largest filling ratio close to the one surface, layer Y be a layer with a filling ratio smaller than layer X close to the other surface, and layer Z be the layer positioned between layer X and layer Y for layers obtained by dividing the carbon sheet equally into three in a direction perpendicular to the surfaces, the filling ratio for the layers becomes smaller in order of layer X, layer Y, and layer Z.

A porous carbon sheet contains a carbon fiber and a binding material, wherein layers are obtained in a section spanning from a plane closest to one of the surfaces and having 50% of the mean fluorine intensity to a plane closest to the other surface and having 50% of the mean fluorine intensity by dividing this section evenly into three in an orthogonal direction to the carbon sheet plane; among the layer close to one of the surfaces and the layer close to the other surface, the layer having the larger layer mean fluorine intensity is designated layer X, the layer having the smaller one is designated layer Y, and the layer between the layer X and the layer Y is designated layer Z; and the layer mean fluorine intensities decrease in the order: layer X, layer Y, and layer Z.

A gas diffusion electrode is provided that enables the achievement of a fuel cell which has high drainage performance and maintains good power generation performance, while exhibiting high power generation performance particularly at a low temperature (40° C.), if used in the fuel cell. The gas diffusion electrode includes a microporous layer on at least one surface of a conductive porous substrate, wherein the microporous layer has a fluorine compound region having a length of 3-10 μm and a void having a length of 3-10 μm.

A method for producing a membrane electrode assembly for a fuel cell comprising a proton exchange polymer membrane, catalyst layers, and first and second gas diffusion layers, the method comprising the following steps: a) forming a catalytic layer coating on a first surface of the membrane, the opposite surface being supported by a spacer; b) forming a catalytic layer coating on a first surface of the first gas diffusion layer; c) bringing the first surface of the first gas diffusion layer into contact with the surface opposite to the said first surface of the membrane, after removing the spacer, and bringing the first surface of the membrane into contact with a surface of the second gas diffusion layer.

An illustrative example method of making a fuel cell component includes mixing a catalyst material with a hydrophobic binder in a solvent to establish a liquid mixture having at least some coagulation of the catalyst material and the hydrophobic binder. The liquid mixture is applied to at least one side of a porous gas diffusion layer. At least some of the solvent of the applied liquid mixture is removed from the porous gas diffusion layer. The catalyst material remaining on the porous gas diffusion layer is dried under pressure.

A gas diffusion layer comprises a carbon sheet and a microporous layer disposed on at least one surface of the carbon sheet, and meeting the requirement “C is equal to or greater than 0”, wherein: C, referred to as “index for simultaneous realization of a required in-plane oxygen permeation coefficient and electrical resistance”, is calculated by subtracting the product of B multiplied by 60 from A and adding 310 to the difference, A, is the rate of oxygen permeation in an in-plane direction in a gas diffusion layer that occurs when a pressure of 0.5 MPa is applied in the through-plane direction to a surface of the gas diffusion layer to compress an arbitrarily selected region having a width of 10 mm and a depth of 3 mm in the gas diffusion layer, and B is the “electrical resistance” that occurs when the gas diffusion layer is compressed by applying a pressure of 2 MPa in the through-plane direction.

Cohesive carbon assemblies are prepared by obtaining a functionalized carbon starting material in the form of powder, particles, flakes, loose agglomerates, aqueous wet cake, or aqueous slurry, dispersing the carbon in water by mechanical agitation and/or refluxing, and substantially removing the water, typically by evaporation, whereby the cohesive assembly of carbon is formed. The method is suitable for preparing free-standing, monolithic assemblies of carbon nanotubes in the form of films, wafers, discs, fiber, or wire, having high carbon packing density and low electrical resistivity. The method is also suitable for preparing substrates coated with an adherent cohesive carbon assembly. The assemblies have various potential applications, such as electrodes or current collectors in electrochemical capacitors, fuel cells, and batteries, or as transparent conductors, conductive inks, pastes, and coatings.

A method for producing porous graphite capable of realizing higher durability, output and capacity, and porous graphite. A carbon member having microvoids is obtained by a dealloying step for selectively eluting other non-carbon main components into a metal bath by immersing a carbon-containing material, composed of a compound including carbon or an alloy or non-equilibrium alloy, in the metal bath, wherein the metal bath has a solidifying point lower than the melting point of the carbon-containing material, and is controlled to a temperature lower than the minimum value of a liquidus temperature within a composition fluctuation range extending from the carbon-containing material to carbon by reducing the other non-carbon main components. The carbon member obtained in the dealloying step is graphitized by heating in a graphitization step. The carbon member graphitized in the graphitization step is subjected to activation treatment by an activation step.

A power generation cell includes a resin-framed electrolyte membrane electrode assembly. The cathode of the resin-framed membrane electrode assembly has a larger surface dimension than the anode. An outer peripheral portion of the anode is positioned between a first buffer and a fuel gas flow field. An outer peripheral portion of the cathode is positioned between the resin frame member and the second buffer.

To provide a fuel cell production method configured to suppress the formation of a blister in a thermoplastic sheet. The production method is a method for producing a fuel cell, wherein the method comprises: a first attaching step, a disposing step and a second attaching step in which, after the disposing step, the membrane electrode assembly and the resin frame are attached via the thermoplastic sheet, and the membrane electrode assembly and the gas diffusion layer are attached via the thermoplastic sheet.