Disclosed are a manufacturing method of a membrane electrode assembly capable of increasing the interfacial adhesion between a polymer electrolyte membrane and a catalyst layer, improving substance delivery and performance, and enhancing hydrogen permeation resistance or oxygen permeability; a membrane electrode assembly manufactured thereby; and a fuel cell comprising the membrane electrode assembly. The manufacturing method of the present invention comprises the steps of: adding a catalyst and a first ionomer to a solvent and dispersing the same, thereby producing a dispersed mixture; adding a second ionomer to the dispersed mixture, thereby producing a coating composition; and applying the coating composition directly onto at least one side of the polymer electrolyte membrane.

A composite polymer electrolyte membrane comprising a nanofiber sheet having a basis weight of 1.5 g/m.sup.2 or more and 4.0 g/m.sup.2 or less, and a proton-conducting polymer, the electrolyte membrane having a sheet shape in which the proton-conducting polymer and the nanofiber sheet are combined, and having an average coefficient of linear expansion of 300 ppm/K or less from 20° C. to 120° C. in an in-plane direction of the sheet shape.

The present invention provides a catalysed ion-conducting membrane comprising an ion-conducting membrane, an electrocatalyst layer having two opposing faces, and a layer A comprising an ion-conducting material and a carbon containing material. Also provided are methods for preparing the catalysed ion-conducting membrane.

A fuel cell includes a cell stacked body and a manifold. The cell stacked body has elements stacked, each element having: a fuel electrode and an oxidant electrode between which the electrolyte membrane is interposed; a fuel electrode flow channel plate; and an oxidant electrode flow channel plate. The manifold is provided on a lateral surface, of the cell stacked body, along a stacking direction of the cell stacked body and feeds a reaction gas to the fuel electrode flow channel plate or the oxidant electrode flow channel plate. The manifold includes a gas flow channel part that is provided between a plurality of the cell stacked bodies arranged to line up in a first direction perpendicular to the stacking direction and that allows communication between the cell stacked bodies such that the reaction gas passes through.

In order to provide an electrochemically active unit for an electrochemical device including a membrane electrode assembly, at least one gas diffusion layer and a seal that is linked to at least one of the at least one gas diffusion layers, in the manufacture whereof as even as possible a construction of the penetration region in which the gas diffusion layer of the electrochemically active unit is penetrated by the sealing material of the seal over the periphery of the gas diffusion layer is achievable, the seal includes a linking region, a distribution region and a connection region that connects the linking region and the distribution region to one another, wherein the connection region has a minimum height that is less than a quarter of the maximum height of the distribution region and less than a quarter of the maximum height of the linking region.

An electrode catalyst layer that suppresses degradation due to repeated starting and stopping and has excellent durability, and a membrane electrode assembly using the electrode catalyst layer. The electrode catalyst layer is an electrode catalyst layer used in a polymer fuel electrolyte fuel cell, which contains carbon particles which support catalyst, a polymer electrolyte, and a fiber material which is at least one of a carbon fiber and an organic electrolyte fiber, and the thickness of the electrode catalyst layer after performing a start-stop test from 1 V to 1.5 V for 10,000 cycles is 70% or more of the thickness of the electrode catalyst layer before the start-stop test.

Provided is an oxygen reduction catalyst having an excellent oxygen reduction catalytic activity and a selection method thereof, a liquid composition or electrode containing an oxygen reduction catalyst, and an air battery or fuel cell provided with the electrode. An oxygen reduction catalyst containing a metal complex and a conductive material and having an ionization potential value of 5.80 eV or lower and a selection method thereof, a liquid composition or electrode containing an oxygen reduction catalyst, and an air battery or fuel cell provided with electrode.

An energy conversion device for conversion of chemical energy into electricity. The energy conversion device has a first and second electrode. A substrate is present that has a porous semiconductor or dielectric layer placed thereover. The porous semiconductor or dielectric layer can be a nano-engineered structure. A porous catalyst material is placed on at least a portion of the porous semiconductor or dielectric layer such that at least some of the porous catalyst material enters the nano-engineered structure of the porous semiconductor or dielectric layer, thereby forming an intertwining region.

An energy conversion device for conversion of chemical energy into electricity. The energy conversion device has a first and second electrode. A substrate is present that has a porous semiconductor or dielectric layer placed thereover. The porous semiconductor or dielectric layer can be a nano-engineered structure. A porous catalyst material is placed on at least a portion of the porous semiconductor or dielectric layer such that at least some of the porous catalyst material enters the nano-engineered structure of the porous semiconductor or dielectric layer, thereby forming an intertwining region.

A method for preparing a support for an electrode catalyst including forming first and second polymer layers having charges different from each other on a surface of a carbon support and carbonizing the result, wherein the polymers included in the first and the second polymer layers are an aromatic compound including a heteroatom, and the first or the second polymer includes a pyridine group.