An analysis of the reversible and irreversible degradation of a PEM fuel cell short-stack operated under simulated maritime conditions

A PEMFC short stack was operated for 1500 h under maritime-relevant conditions by applying alternating 125 h periods of constant load and a dynamic maritime load profile. The reversible and irreversible degradation rates were quantified, with the reversible degradation dominating for both segment types, but being around 2.5 times higher for the constant segments than the dynamic (52 μV h −1 compared to 22). This implies that the reversible degradation should be actively mitigated regardless of type of vessel operation and hybridisation strategy, as it can lead to significant drops in the stack voltage and therefore efficiency. The average irreversible degradation increased from 1.2 to 4.8 μV h −1 when going from static to dynamic cycles. This degradation was found to be due to a cathode ECSA loss of around 20 %, with no notable increase in hydrogen crossover or HFR, indicating membrane stability during the testing period. • A commercial PEMFC short-stack was tested under simulated maritime conditions. • Reversible degradation was found to dominate, particularly under constant operation. • Irreversible degradation rates as low as 1.2 μV h −1 were recorded. • Irreversible losses were due to a 20 % loss in cathode ECSA over the testing period.