Modeling of Pt Degradation in Polymer Electrolyte Fuel Cells: Effect of Electrode Potential Cycles

Being a promising alternative to combustion engines, the polymer electrolyte fuel cell still suffers durability issues. Specifically, the Pt catalyst degrades dramatically during dynamic operating conditions. Here, a Pt degradation model is developed and used to study the effect of accelerated stress test, i.e. electrode potential cycles, on Pt degradation. For triangle wave potential cycles, the ECSA loss rate is independent of a high potential sweep rate. For trapezoidal wave potential cycles with the same cycle duration, the ECSA loss rate is accelerated by a high potential sweep rate. Comparing two types of wave cycles, the trapezoidal cycle better accelerates Pt degradation than the triangle cycle. The effect of trapezoidal cycle duration is also studied. The results show that the ECSA loss rate is independent of the cycle duration, while the Pt mass tends to transport from the catalyst layer to the membrane with a longer cycle duration.