Evaluation of HT-PEM MEAs: Load cycling versus start/stop cycling

With the help of consistent conditions for improved batch production and defined quality standards, the lifetime of fuel cell systems should be improved and cost-intensive losses should be minimized at an early state in the production process. Within this work, we concentrated on two accelerated stress tests: load cycling at high current densities and start/stop cycling to compare high temperature (HT) polymer electrolyte membrane (PEM) membrane electrode assemblies (MEAs) of three suppliers to evaluate performances and degradation rates under such conditions. These MEAs have been investigated in-situ via electrochemical characterization. MEAs of three providers differ significantly in their performance and power output for both operation strategies. It was also shown that load cyclization causes greater stress on the MEA than start/stop cycling. Next to the manufacturer comparison, a batch-to-batch evaluation of one provider has been performed including micro-computed tomography (μ-CT) investigations and the determination of the tortuosity of the cathode side gas diffusion layers.