Study of relative humidity on durability of the reversal tolerant proton exchange membrane fuel cell anode using a segmented cell

Cell voltage reversal resulted from hydrogen starvation at the anode is one of the factors that exacerbate the overall degradation of proton exchange membrane fuel cells (PEMFCs). An effective mitigation strategy is to involve oxygen evolution reaction (OER) catalysts into the anode to facilitate water electrolysis against carbon corrosion. As such, this paper aims to study the influence of relative humidity (RH) on the performance and durability of reversal-tolerant-anodes (RTAs) during hydrogen starvation. An advanced segmented technique is employed to examine the coupling reactions by simultaneously measuring current density, RH and temperature in a fuel cell with a large active area. It is found that the inlet of RTAs undergoes degradation earlier than the outlet and the membrane electrode assembly (MEA) with a RTA has an optimal humidity during cell reversal. Results also show that the failure of the RTA MEA is due to a loss of electron conduction medium rather than the deactivation of the OER catalyst. In addition, this work highlights the importance of plate flow field design and the OER catalyst gradient design of the RTA MEA.