The copolymer includes divalent units represented by formula —[CF.sub.2—CF.sub.2]—, at least one divalent unit represented by formula (I): and at least one divalent unit independently represented by formula (II): A is —N(RF.sup.a).sub.2 or a is non-aromatic, 5- to 8-membered, perfluorinated ring comprising one or two nitrogen atoms in the ring and optionally comprising at least one oxygen atom in the ring, each RFa is independently linear or branched perfluoroalkyl having 1 to 8 carbon atoms and optionally interrupted by at least one catenated O or N atom, each Y is independently —H or —F, with the proviso that one Y may be —CF.sub.3, h is 0, 1, or 2, each i is independently 2 to 8, and j is 0, 1, or 2. A catalyst ink and polymer electrolyte membrane including the copolymer are also provided.

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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.

An anode catalyst layer with high reversal tolerant capability includes an anode inner catalyst layer close to a proton exchange membrane and an anode outer catalyst layer close to a gas diffusion layer. At least the anode inner catalyst layer contains a reversal tolerant catalyst and a hydrophilic additive. The content of the hydrophilic additive in the anode inner catalyst layer is not less than that of the anode outer catalyst layer, or the water retention capability of the anode inner catalyst layer is not less than that of the anode outer catalyst layer.

Disclosed are a method of manufacturing a membrane-electrode assembly and a membrane-electrode assembly manufactured using the same. The method includes forming a laminated structure, and treating the laminated structure, for example, by drying and heat treating. The laminated structure includes a release film, an anode layer, a porous support layer, and a cathode layer.

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 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.

Disclosed are a catalyst for an electrochemical cell and a method of manufacturing the catalyst. The catalyst includes a support, a first catalyst supported on the support, wherein the first catalyst is a catalyst for hydrogen oxidation reaction (HOR) or oxygen reduction reaction (ORR), a second catalyst supported on the first catalyst, wherein the second catalyst is a catalyst for oxygen evolution reaction (OER), and a protective layer formed on the first catalyst and the second catalyst.

A composite for a porous transport layer may include a particulate substrate including at least one selected from a group consisting of an oxide of a first metal and a second metal, and nanoparticles of a third metal formed on a surface of the particulate substrate, a sintered body thereof, and a method for preparing the same.

There is provided a method for manufacturing a catalyst ink for fuel cell electrodes that allows simultaneously performing fineness of a catalyst and adjustment of viscosity of the catalyst ink. The method for manufacturing a catalyst ink for fuel cell electrodes containing a catalyst, a solvent, and an ionomer includes stirring and mixing the catalyst, the solvent, and the ionomer by a high-shear thin-film spin mixer. The ionomer contains a gel-like ionomer. The high-shear thin-film spin mixer includes a cylindrical stirring tank, a rotary vane, and a shaft. The cylindrical stirring tank has unevennesses on an inner peripheral surface. The rotary vane is concentric with the stirring tank and has an outer diameter slightly smaller than an inner diameter of the stirring tank. The shaft includes the rotary vane on an end portion and is rotatable at high speed in forward and reverse directions.

A membrane-electrode assembly, a method for manufacturing the membrane-electrode assembly, and a fuel cell including the membrane-electrode assembly are disclosed. The membrane-electrode assembly includes: an ion exchange membrane; catalyst layers disposed on both sides of the ion exchange membrane respectively; and a functional modification layer disposed between the ion exchange membrane and each of the catalyst layers. The membrane-electrode assembly has a low hydrogen permeability without a reduction of hydrogen ion conductivity, has excellent interfacial bonding properties between the catalyst layers and the ion exchange membrane, and has excellent performance and durability under high temperature/low humidity conditions.