The Ionomer Segregation in Composite Membrane Electrode Assemblies and the Effect on the Performance of Polymer Electrolyte Fuel Cells

摘要

The membrane electrode assembly (MEA) is formed by hot pressing the two thin catalyst layers on both sides of a membrane electrolyte [1].The formed catalyst layer is a porous composite,consisting of the recast Nafion~R ionomer,and the nano-particle precious metal catalyst supported on micro-particle carbon.As a gas electrode,the structure of catalyst layer needs to facilitate gas diffusion from outside to inside and water removal from the reverse direction.The surface features of the catalyst layer have an important impact on the performance of the MEA because both gas diffusion and water removal have to go through the surface.