Proton-exchange-membrane fuel cells durability evaluated by load-on/off cycling

Load-on/off cycles at 80 °C, with near-saturated H2 and air at ambient pressure were applied to investigate the durability of several types of membrane-electrode-assemblies (MEAs) for proton-exchange-membrane fuel cells (PEMFC). The ohmic resistance, H2 cross-over, electrochemically active surface area (ECSA), protonic resistance of the cathode as well as the performances with H2/air and H2/O2 were measured at regular intervals. These data enabled a breakdown of the increase in cell voltage losses upon cycling. Increase of kinetic losses was found in all MEAs but significant differences were obtained for the transport losses in the cathode catalyst layer, which either had a small or a substantial contribution to the overall voltage decay, depending on the carbon type and ionomer loading. Membrane degradation did not contribute significantly in these tests.