HIGH-PERFORMANCE CATALYZED MEMBRANES OF ULTRA-LOW PT LOADINGS FOR POLYMER ELECTROLYTE FUEL-CELLS

Polymer electrolyte membranes are catalyzed by the direct application of thin film catalyst layers cast from solutions of suspended Pt/C catalyst and solubilized Nafion(R) ionomer. Both the ionomeric membrane and the solubilized ionomer are in the Na+ form during casting to enable higher curing temperatures, which results in more robust catalyst layers. In addition to simplifying the fabrication process, the direct application apparently provides enhanced bonding at the interface between the membrane and the catalyst layer. Consequently, the performances of fuel cells utilizing these catalyzed membranes with ultra-low platinum loadings are superior to those achieved with other approaches to polymer electrolyte membranes of low Pt loading.