Performance Improvement of a Proton Exchange Membrane Fuel Cell Through the Electrode Structure Change

A new hydrophobic micropillared structure for the electrode of a proton exchange membrane fuel cell (PEMFC) is proposed in this study. Its performance has a 40% increase over the conventional structured electrode. The new design changes the gas-diffusion layer (also called microporous layer (MPL)) of the cathode of a PEMFC to a gas-abundant-layer (GAL) by mixing a high percentage of polytetrafluoroethylene (PTFE) into the carbon powder. Unlike the generally flat MPL, the surface of the GAL in contact with the catalyst layer has tens of thousands of micropillars on top of it so that its area can be increased significantly. The interfacial region between the GAL and the catalyst layer will become the main reaction sites because the heavily PTFE treated GAL will be filled with oxygen passageways while most of the catalyst layer of the cathode will eventually be filled with the water produced in the operation. The experimental results with different pillar sizes have shown that the area of the interfacial surface between the GAL and the catalyst layer is the key factor in determining the cell performance and should be made as large as possible.