	US 7,476,459 B2
	Membrane electrode assembly and fuel cell
Toshiya Wakahoi, Utsunomiya (Japan); Tetsuya Komori, Utsunomiya (Japan); Masaaki Nanaumi, Utsunomiya (Japan); and Junichi Yano, Utsunomiya (Japan)
Assigned to Honda Motor Co., Ltd., Tokyo (Japan)
Filed on Dec. 22, 2004, as Appl. No. 11/22,404.
Claims priority of application No. 2003-426384 (JP), filed on Dec. 24, 2003; and application No. 2004-072734 (JP), filed on Mar. 15, 2004.
Prior Publication US 2005/0142397 A1, Jun. 30, 2005
Int. Cl. H01M 4/90 (2006.01); H01M 2/08 (2006.01)

U.S. Cl. 429—40 [429/43; 429/34; 429/36]

8 Claims

1. A membrane electrode assembly for use in a fuel cell, said membrane electrode assembly comprising:

first and second electrodes, wherein at least one of the first and second electrodes includes a catalyst layer formed of a catalyst material;

a solid polymer electrolyte membrane interposed between said first and second electrodes, wherein the catalyst layer contacts a first surface of the solid polymer electrolyte membrane;

an adhesive layer formed of an adhesive material, the adhesive layer adhering to the first surface of the solid polymer electrolyte membrane; and

a mixture layer formed of the catalyst material and the adhesive material and having a predetermined thickness, the mixture layer contacting the first surface of the said polymer electrolyte membrane and being disposed between said electrode catalyst layer and said adhesive layer,

wherein a peripheral surface of said electrode catalyst layer contacts a first peripheral surface of the said mixture layer, and a peripheral surface of said adhesive layer contacts a second peripheral surface of said mixture layer,

wherein a density of the catalyst material decreases along the mixture layer from the first peripheral surface to the second peripheral surface of the mixture layer, and a density of the adhesive material increases along the mixture layer from the first peripheral surface to the second peripheral surface of the mixture layer.