| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a membrane electrode assembly, by which gas permeability of ionomer contained in an electrode catalyst layer can be improved. <P>SOLUTION: Using a catalyst ink including ionomer and a catalyst carrier that has already carried a catalyst, an anode 52 and a cathode 53 that are electrode catalyst layers are formed on both membrane faces of an electrolyte membrane 51 to produce MEA. Then, the MEA is subject to gas permeability improving processing (step S300). This gas permeability improving processing is a processing to reduce a dense region because the ionomer of the electrode catalyst layer exhibits a crystal phase, and increase a coarse region that is coarse and has high gas permeability because the ionomer exhibits an amorphous phase. In such a method, an inside of the electrode catalyst layer of the MEA is impregnated with water, and the impregnated water is frozen. Thereafter, the water is thawed and dry-removed. An orientation of molecules in the crystal phase is disturbed by expansion of the water during freezing, and the crystal phase is made coarse as is similar to the amorphous phase. <P>COPYRIGHT: (C)2013,JPO&INPIT |
