| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an ion conductive binder which is excellent in the electrode reaction efficiency, and is useful in reducing the amount of precious metal catalysts used in the catalyst layer, and in improving the battery efficiency in the membrane-electrode assembly and the solid polymer electrolyte fuel cell. <P>SOLUTION: The ion conductive binder is used for a gas diffusion electrode composing a membrane-electrode assembly for a solid polymer electrolyte fuel cell comprising a polymer electrolyte membrane and two gas diffusion electrodes joined to the electrolyte membrane by sandwiching the membrane, and contains, as components, an aromatic vinyl polymer block (A) such as polystyrene and a rubber-like polymer block (B) consisting of conjugated diene unit or isobutylene unit such as hydrogenated isoprene, butadiene or the like, resulting in a star-shaped block copolymer having ion conductive group being contained which is expressed by the equation (A-B-)<SB>n</SB>X (X is a residue of coupling agent, and n is any number exceeding 2). <P>COPYRIGHT: (C)2008,JPO&INPIT |
