Start-Stop Phenomena in Channel and Land Areas of a Polymer Electrolyte Fuel Cell (PEFC)

In this work, we focus on effects of the flow field design and the operation conditions on local current transients, which are induced by start-up and shutdown processes in a polymer electrolyte fuel cell (PEFC). Submillimeter resolved in situ diagnostics are employed for the measurement of local current transients in the areas of channel and land. Local current transients have been proposed to play a significant role in the degradation of the catalyst layer. Therefore, start-stop processes are evaluated as a source for degradation by using local CO stripping voltammetry. In addition, local effects of proposed mitigation strategies are presented. First results of local degradation in channel and land areas indicate a higher degradation in the land areas after a series of start-stop cycles.