Abstract: An object of the present invention is to provide an electrode substrate that maintains electrical conductivity and achieves both a high drainage performance and any one of a high gas diffusivity and spring property. To achieve the above-described object, an electrode substrate according to the present invention is an electrode substrate including a carbon fiber sheet having pores filled with a fluoropolymer and carbon fine powder, wherein, in terms of a fluorine/carbon ratio (F/C), the ratio of the smallest value (F/Cmin) to the largest value (F/Cmax) of the average value (F/C-1) in one surface of the electrode substrate, the average value (F/C-2) in the central plane in the thickness direction, and the average value (F/C-3) in the other surface is 0.80 or more, and wherein, in a pore size distribution, the electrode substrate has at least a first peak present in the range of pore size of 0.5 ?m or more and less than 120 ?m and a second peak present in the range of pore size of 10 nm or more and less than 0.

Abstract: An object of the present invention is to shorten the aging time for a fuel cell. To achieve the object, a gas diffusion electrode medium product according to the present invention includes sulfuric acid in an amount of 1.1 ?g/cm2 or less. In addition, a polymer electrolyte fuel cell according to the present invention has the gas diffusion electrode medium product according to the present invention incorporated therein.

Abstract: In order to provide a gas diffusion electrode medium having high thermal conductivity despite having low density and excellent both in handleability and cell performance, provided is a gas diffusion electrode medium including carbon fiber felt including carbon fibers having an average fiber diameter of 5 to 20 ?m, wherein at least a part of the carbon fibers that constitute the carbon fiber felt have a flat part in which, in a plane view of a surface of the carbon fiber felt, a maximum value of a fiber diameter is observed to be 10 to 50% larger than the average fiber diameter, and a frequency of the flat parts at the surface of the carbon fiber felt is 50 to 200/mm2.

Abstract: 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.

Abstract: A fuel cell with high productivity, high power generation performance and high durability is described, along with a gas diffusion electrode base material having a microporous layer on one side of an electrically conductive porous base material, where the electrically conductive porous base material contains carbon fiber and resin carbide and has a density of 0.25 to 0.39 g/cm3 and a pore mode diameter in a range of 30 to 50 ?m. The microporous layer contains a carbonaceous powder and a fluororesin and has a surface roughness of 2.0 to 6.0 ?m, a porosity of 50 to 95%, and a pore mode diameter of 0.050 to 0.100 ?m.

Abstract: The objective of the present invention is to provide a method which is for producing a gas diffusion electrode substrate having a high conductivity and a chemical resistance, and by which an increase in production cost can be suppressed. The present invention is a method for producing a gas diffusion electrode substrate in which a microporous layer is formed in a conductive porous body formed by bonding carbon fibers to each other by means of a cured product of a binder resin, the method having, in the following order: a binder resin impregnation step in which a carbon fiber structure is impregnated with a binder resin composition to obtain a pre-impregnated body; a coating step in which the surface of the pre-impregnated body is coated with a microporous layer coating solution; and a heat treatment step in which the pre-impregnated body that has been subjected to the coating step is heat-treated at a temperature of at least 200° C.

Abstract: The present invention provides a micro-porous layer which provides a fuel battery having high productivity, high power generation performance, and high durability. The present invention provides a micro-porous layer including fibrous carbohydrate having a fiber diameter of 5 nm-10 ?m and an aspect ratio of 10 or more. The carbohydrate has an oxygen/carbon element ratio of 0.02 or more.

Abstract: 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 ?m and a void having a length of 3-10 ?m.

Abstract: In order to provide a gas diffusion electrode medium having high thermal conductivity despite having low density and excellent both in handleability and cell performance, provided is a gas diffusion electrode medium including carbon fiber felt including carbon fibers having an average fiber diameter of 5 to 20 ?m, wherein at least a part of the carbon fibers that constitute the carbon fiber felt have a flat part in which, in a plane view of a surface of the carbon fiber felt, a maximum value of a fiber diameter is observed to be 10 to 50% larger than the average fiber diameter, and a frequency of the flat parts at the surface of the carbon fiber felt is 50 to 200/mm2.

Abstract: The purpose of the present invention is to provide: a method for producing a gas diffusion electrode base which enables the achievement of a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane; and a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane. For the purpose of achieving the above-described purpose, the present invention has the configuration described below. Namely, a specific gas diffusion electrode base which has a carbon sheet and a microporous layer, and wherein the carbon sheet is porous and the DBP oil absorption of a carbon powder contained in the microporous layer is 70-155 ml/100 g.

Abstract: A low-cost gas diffusion electrode is described that overcomes defects of conventional techniques, that achieves both dry-up resistance and flooding resistance, and that has satisfactory power generation performance, where the gas diffusion electrode includes a conductive porous substrate, and a microporous layer containing conductive fine particles and provided on at least one surface of the conductive porous substrate. The gas diffusion electrode has, based on the number of fine pores having an area of 0.25 ?m2 or more that are observed in a cross section of the microporous layer in a thickness direction, a percentage of fine pores having a circularity of 0.5 or more of 50% or more and 100% or less.

Abstract: The purpose of the present invention is to provide an electrode which is used as a liquid flow-through device electrode and in which liquid flow-through resistance is reduced and the utilization efficiency of carbon fiber is enhanced. Another object of the present invention is to provide a redox flow battery having excellent charge-discharge performance by use of the electrode which is used for the liquid flow-through device. The present invention provides an electrode for a liquid flow-through device, the electrode essentially consisting of a carbon fiber nonwoven fabric, having a thickness of more than 0.40 mm, and having a through-hole disposed therein, or a non-through-hole disposed on one surface or both surfaces of the electrode.

Abstract: 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.

Abstract: A fuel cell with high productivity, high power generation performance and high durability is described, along with a gas diffusion electrode base material having a microporous layer on one side of an electrically conductive porous base material, where the electrically conductive porous base material contains carbon fiber and resin carbide and has a density of 0.25 to 0.39 g/cm3 and a pore mode diameter in a range of 30 to 50 ?m. The microporous layer contains a carbonaceous powder and a fluororesin and has a surface roughness of 2.0 to 6.0 ?m, a porosity of 50 to 95%, and a pore mode diameter of 0.050 to 0.100 ?m.

Abstract: A low-cost gas diffusion electrode is described that overcomes defects of conventional techniques, that achieves both dry-up resistance and flooding resistance, and that has satisfactory power generation performance, where the gas diffusion electrode includes a conductive porous substrate, and a microporous layer containing conductive fine particles and provided on at least one surface of the conductive porous substrate. The gas diffusion electrode has, based on the number of fine pores having an area of 0.25 ?m2 or more that are observed in a cross section of the microporous layer in a thickness direction, a percentage of fine pores having a circularity of 0.5 or more of 50% or more and 100% or less.

Abstract: The purpose of the present invention is to provide: a method for producing a gas diffusion electrode base which enables the achievement of a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane; and a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane. For the purpose of achieving the above-described purpose, the present invention has the configuration described below. Namely, a specific gas diffusion electrode base which has a carbon sheet and a microporous layer, and wherein the carbon sheet is porous and the DBP oil absorption of a carbon powder contained in the microporous layer is 70-155 ml/100 g.

Abstract: An object of the present invention is to provide an electrode which is used for a liquid flow-through device and in which liquid flow-through resistance is reduced and the utilization efficiency of the surface of carbon fiber is enhanced. Another object of the present invention is to provide a redox flow battery having excellent charge-discharge performance by use of the electrode which is used for the liquid flow-through device. The present invention provides an electrode to be used for a liquid flow-through device, the electrode including a plurality of sheets of carbon fiber nonwoven fabric each having irregularities on a surface of the sheet of carbon fiber nonwoven fabric being stacked or each having a through-hole on the carbon fiber sheet being stacked, and having inside of the electrode a plurality of gaps which is formed by recesses of the irregularities or the through-hole and is not opened in a thickness direction.

Abstract: A gas diffusion electrode in which a microporous layer is provided on at least one surface of a conductive porous substrate, wherein the areas obtained by dividing the cross section perpendicular to the plane of the microporous layer into three equal parts in the thickness direction are a first area, a second area, and a third area, with respect to the conductive porous substrate side, the fluorine strength of the third area being 0.8 to 1.2 times the fluorine strength of the second area.

Abstract: A porous carbon sheet includes a carbon fiber and a binding material, wherein when in a measured surface depth distribution, a ratio of an area of a portion having a depth of 20 ?m or less in a measured area of one surface is a surface layer area ratio X, and a ratio of an area of a portion having a depth of 20 ?m or less in a measured area of another surface is a surface layer area ratio Y, the surface layer area ratio X is larger than the surface layer area ratio Y, and a difference between the surface layer area ratios is 3% or more and 12% or less.

Abstract: A gas diffusion electrode has a microporous layer on at least one surface of an electrical conducting porous substrate. The microporous layer has at least a first microporous layer in contact with the electrical conducting porous substrate, and a second microporous layer. The gas diffusion electrode has a pore size distribution with a peak at least in a first region of 10 ?m or more and 100 ?m or less, a second region of 0.2 ?m or more and less than 1.0 ?m, and a third region of 0.050 ?m or more and less than 0.2 ?m. The total volume of the pores in the second region is 10% or more and 40% or less of the total volume of the pores in the first region, and the total volume of the pores in the third region is 40% or more and 80% or less of the total volume of the pores in the second region.