Design Focus of Anodes toward High-Current-Density Low-Pt-Loading Proton Exchange Membrane Fuel Cells

Based on the demand of low total Pt loading and high current density for proton exchange membrane fuel cells, it is necessary to further lessen the anode Pt loading to reserve enough space for the cathode. In terms of high current density, the anode must facilitate the rapid oxidation of hydrogen to generate protons while ensuring rapid proton conduct. Proton conduct is highly related to the water content of the catalyst layer. Therefore, in this work, the effects of anode design with low Pt loading under high current density was studied in depth via comparing the single cell performance, electrochemical H2-pumping test, electrochemical impedance spectroscopy, and analysis of distribution of relaxation times. It is found that the hydrogen oxidation reaction activation overpotential does not significantly deteriorate even at an anode Pt loading of 0.01 mgPt/cm2. However, the thickness of the anode catalyst layer, namely, the water retention capability, has a great impact on proton conduction resistance under high current density operating conditions.