Provided is an electrode catalyst in which the contents of chlorine (Cl) species and bromine (Br) species are reduced to a predetermined level or lower, capable of exhibiting sufficient catalyst performance. The electrode catalyst has a core-shell structure including a support, a core part formed on the support and a shell part formed to cover at least a part of the surface of the core part. A concentration of bromine (Br) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 400 ppm or less, and a concentration of chlorine (Cl) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 900 ppm or less.

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/cm.sup.3 and a pore mode diameter in a range of 30 to 50 μm. The microporous layer contains a carbonaceous powder and a fluororesin and has a surface roughness of 2.0 to 6.0 μm, a porosity of 50 to 95%, and a pore mode diameter of 0.050 to 0.100 μm.

A stable form which uses a carbon material having electrical conductivity as a raw material and that the electrical conductivity of the carbon material is retained and/or improved, and which improves the electricity generation properties when used in a catalyst layer for a fuel cell. The present invention is directed to, e.g., a calcined material of a mixture of an aromatic compound having a phenolic hydroxyl group and a carbon material having electrical conductivity.

To provide a membrane electrode assembly capable of forming a fuel cell excellent in power generation efficiency, and a polymer electrolyte fuel cell. The membrane electrode assembly of the present invention comprises an anode having a catalyst layer containing a proton-conducting polymer and a catalyst, a cathode having a catalyst layer containing a proton-conducting polymer and a catalyst, and a solid polymer electrolyte membrane disposed between the anode and the cathode, wherein the proton-conducting polymer contained in the catalyst layer of at least one of the anode and the cathode, is a polymer (H) having a cyclic ether structural unit and an ion exchange group, and the solid polymer electrolyte membrane contains a fluorinated polymer (S) having an ion exchange group; and the thickness of the solid polymer electrolyte membrane is from 5 to 15 μm, and the ratio of the content M1 [mol %] of the cyclic ether structure unit to the thickness T1 [μm] of the solid polymer electrolyte membrane is 4.5 or more.

A method for operating a propulsion system for an aircraft, the propulsion system including a gas turbine engine and a fuel cell assembly, the fuel cell assembly including a fuel cell stack having a solid oxide fuel cell defining an outlet positioned to remove output products from the solid oxide fuel cell during operation, the method including: operating the fuel cell assembly to provide output products to a combustor of a combustion section of the gas turbine engine; and operating the fuel cell assembly, the gas turbine engine, or both such that a pressure within an anode of the solid oxide fuel cell is less than a pressure within a cathode of the solid oxide fuel cell, is less than a pressure within a combustion chamber of the gas turbine engine, or both while operating the gas turbine engine.

The present disclosure relates to a polymer electrolyte membrane for medium and high temperature, a preparation method thereof and a high-temperature polymer electrolyte membrane fuel cell including the same, more particularly to a technology of preparing a composite membrane including an inorganic phosphate nanofiber incorporated into a phosphoric acid-doped polybenzimidazole (PBI) polymer membrane by adding an inorganic precursor capable of forming a nanofiber in a phosphoric acid solution when preparing phosphoric acid-doped polybenzimidazole and using the same as a high-temperature polymer electrolyte membrane which is thermally stable even at high temperatures of 200-300° C. without degradation of phosphoric acid and has high ion conductivity.

The invention relates to a fuel cell (1) for a fuel cell stack (11), comprising a polymer membrane (2) which serves as an electrolyte and has respectively on both sides a catalyst layer (3, 4) for forming an anode (3) on the one side and a cathode (4) on the other side, a gas diffusion layer (5) and a bipolar plate (6) being applied to each of the two analyst layers (3, 4). According to the invention, a short-circuit element (7) is applied, preferably printed, to at least one bipolar plate (6). namely on the side facing away from the gas diffusion layer (5). The invention also relates to a fuel cell stack (11) and to a inetliod for operating a fuel cell stack (11).

A method for producing a microporous material comprising the steps of: providing an ultrahigh molecular weight polyethylene (UHMWPE); providing a filler; providing a processing plasticizer; adding the filler to the UHMWPE in a mixture being in the range of from about 1:9 to about 15:1 filler to UHMWPE by weight; adding the processing plasticizer to the mixture; extruding the mixture to form a sheet from the mixture; calendering the sheet; extracting the processing plasticizer from the sheet to produce a matrix comprising UHMWPE and the filler distributed throughout the matrix; stretching the microporous material in at least one direction to a stretch ratio of at least about 1.5 to produce a stretched microporous matrix; and subsequently calendering the stretched microporous matrix to produce a microporous material which exhibits improved physical and dimensional stability properties over the stretched microporous matrix.

The present invention provides a method of operating a fuel cell, which method enables a polymer electrolyte membrane to be humidified sufficiently under high-temperature conditions, and can obtain excellent power generation performance. The present invention is a method of operating a fuel cell including a membrane electrode assembly containing an electrolyte membrane, catalyst layers, and gas diffusion layers, the method including a step of setting the operating temperature of the fuel cell at 100° C. or more, wherein, in the step, the relative humidity of supply gas to be supplied to the fuel cell is 70% or more, and the back pressure of the supply gas is 330 kPa or more.

A membrane-electrode assembly including a polymer electrolyte membrane, and electrocatalyst layers disposed on both surfaces of the polymer electrolyte membrane, with a total light transmittance measured after delamination of both the electrocatalyst layers by using an adhesive member is 40% or less. The total light transmittance is at an electrocatalyst layer located part, when a total light transmittance at an electrocatalyst layer non-located part is taken to be 100%. The viscous member has an adhesive force of 3 N/10 mm or more when measured by pulling the viscous member adhered to a stainless steel in a 180°angle direction relative to the stainless steel, for delamination from the stainless steel.