Catalyst Layer/MEA Performance Evaluation

The membrane electrode assembly (MEA) is a key unit of proton exchange membrane (PEM) fuel cells, including direct methanol fuel cells (DMFCs). In general, the MEA is composed of an anode gas diffusion layer (GDL), an anode catalyst layer, a membrane (the PEM), a cathode catalyst layer, and a cathode gas diffusion layer. The MEA materials, structures, components and fabrication technologies have strong effects on the corresponding fuel cell performance. In particular, the catalyst layers, where the electrochemical reactions take place, are the most important components. Theoretically, in an ideal catalyst layer all catalyst particle sites would be accessible to the reactant gas (H

2

or O

2

), protons, and electrons. In order to achieve this, the distributions of the electron conductor, proton conductor, catalyst sites, and gas pores should be uniform in a catalyst layer.