An electrochemical device can include a cathode layer including an ionic conductor material and an electronic conductor material. The cathode layer can include a ratio of (Vi/Ve) of a volume of the ionic conductor material (Vi) to a volume of the electronic conductor material (Ve) of at least 1.3. In an embodiment, the cathode layer can include a median surface diffusion length (Ls) greater than 0.33 microns. In an embodiment, the cathode layer can include a cathode functional layer.

A membrane electrode assembly that can enhance power generation performance, and a polymer electrolyte fuel cell. The membrane electrode assembly for use in a polymer electrolyte fuel cell according to an aspect of the present invention includes a polyelectrolyte membrane, a fuel electrode-side electrocatalyst layer, and an oxygen electrode-side electrocatalyst layer. The fuel electrode- and oxygen electrode-side electrocatalyst layers and contain voids which include pores having a diameter in the range of 3 nm or more and 5.5 μm or less. When the integrated pore volume for all the pores in the fuel electrode- and oxygen electrode-side electrocatalyst layers and is a first integrated volume, the value obtained by dividing the first integrated volume by the mass of the catalytic material contained in both of the electrocatalyst layers is in the range of 2.8 or more and 4.5 or less.

A membrane electrode assembly for a fuel cell includes a catalyst layer having a first main surface and a second main surface, a gas diffusion layer disposed on a side of the first main surface, and an electrolyte membrane disposed on a side of the second main surface, wherein the gas diffusion layer includes a conductive material and a polymer resin, the conductive material comprises a fibrous carbon material, an average fiber diameter D of the fibrous carbon material is equal to or less than 25% of a thickness T of the catalyst layer, and in a cross section in a thickness direction of the catalyst layer, an arithmetic mean roughness Ra1 of the first main surface and an arithmetic mean roughness Ra2 of the second main surface satisfies the relation, Ra1>Ra2.

invention relates to a distributing structure (10) for a fuel cell (1) in the form of a microporous layer, having: a multiplicity of particles (11), wherein the particles (11) are designed to provide the distributing structure (10) with mechanical stability and electrical conductivity, and wherein a multiplicity of pores (P) are formed between the particles (11) for the purposes of distributing reactants (H2, O2) through the distributing structure (10) and of discharging a product water (H2O), the invention providing, for this purpose, a multiplicity of fibres (12), which are distributed within the microporous layer such that the distributing structure (10) has a first diffusion coefficient (D1) in a first planar direction (x) in relation to the plane of extent (x, y) of the microporous layer, and that the distributing structure (10) has a second diffusion coefficient (D2) in a second planar direction (y) in relation to the plane of extent

An electrode catalyst layer includes a catalyst material, a conductive carrier that supports the catalyst material, a polymer electrolyte containing a sulfonate group, and a fibrous material. The electrode catalyst layer includes a first surface configured to be in contact with the polymer electrolyte membrane, and a second surface facing away from the first surface. A first value is obtained by dividing a peak intensity of SO.sub.3 (m/z80) by a peak intensity of carbon (m/z12), and also dividing by a total thickness of the electrode catalyst layer, when the electrode catalyst layer is analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) at each of a plurality of positions in a thickness direction of the electrode catalyst layer from the first surface to the second surface. A rate of change of the first value with respect to a thickness of the electrode catalyst layer is −0.0020 or less.

A cathode configured to use oxygen as a cathode active material includes: a porous electrically conductive framework substrate; and a coating layer disposed on a surface of the porous electrically conductive framework substrate, wherein the coating layer includes at least one of a lithium-containing metal oxide or a composite including a lithium-containing metal oxide, and wherein a porosity of the porous electrically conductive framework substrate is about 70 percent to about 99 percent, based on a total volume of the cathode, and an areal resistance of the porous electrically conductive framework substrate is about 0.01 milliohms per square centimeter to about 100 milliohms per square centimeter.

A fuel cell membrane electrode assembly having: a proton exchange membrane, an anode catalyst coating on one side of the membrane, and a cathode catalyst coating on the other side of the membrane. The cathode catalyst coating has at least two carbon catalyst layers, with a low porosity layer adjacent to a high porosity layer. The high porosity layers have a volume fraction that is higher than the volume fraction of the low porosity layers.

A method for manufacturing an electrochemical device, implementing a process for manufacturing a porous electrode having a porous layer deposited on a substrate, the porous layer having a porosity of between 20% and 60% by volume and pores with an average diameter of less than 50 nm. The method includes providing a substrate and a colloidal suspension including aggregates or agglomerates of monodisperse primary nanoparticles of an active electrode material, having an average primary diameter of between 2 and 60 nm, the aggregates or agglomerates having an average diameter of between 50 nm and 300 nm, then depositing a layer from the colloidal suspension on the substrate, then drying and consolidating the layer to obtain a mesoporous layer, and then depositing a coating of an electronically conductive material on and inside the pores of the layer.

Provided is a metal negative electrode. The metal negative electrode has a first surface and a second surface facing the first surface, and a plurality of grooves may be provided in the first surface.

A cathode catalyst layer and an anode catalyst layer used for a membrane-electrode assembly in a polymer electrolyte fuel cell, wherein the cathode catalyst layer and the anode catalyst layer each include catalyst particles, a conductive carrier, a polymer electrolyte, and a fibrous material, the fibrous material includes at least one of an electron conductor and a proton conductor, and the fibrous material has a specific surface area in a range of 40 m.sup.2/g or more and 80 m.sup.2/g or less.