Development of High Performance Gas-diffusion Electrodes for Fuel Cells

Abstract

High performance gas-diffusion electrodes are essencial for practical fuel cells. Our efforts approaching to high performance have been devoted to the improvement of micro-structure in the porous reaction layer, based on the fundamental requirements to the electrode processes, i,e, high utilization of catalyst clusters and enough gas-supply to the clusters so that an electrochemical reaction on catalyst sites becomes the rate-conrolling process. It was found that a hot-pressing is very important to achieve these requirements resulting from the formation of fine and continuous electrolyte, gas and carbon black networks, respectively. Two preparation methods of high performance electrode were explained in the text, in which one uses a single powder of semi-hydrophobic catalysed carbon black and another one uses a mixed powder of a hydrophilic, catalysed carbon black and a wet-proofed carbon black. Resulting electrodes exhibited larger values both in the utilization and the performance than that prepared by the conventional method by a factor more than 3.