Degradation Mitigation in Polymer Electrolyte Membranes using Free Radical Scavengers

The efficacy of CeO2 nanoparticles in mitigating free radical induced PEM degradation is investigated. Commercially obtained CeO2 and nanoparticles synthesized in-house were incorporated within a recast Nafion® membrane. MEAs were prepared using Nafion® and Nafion®-CeO2 composite membranes (0.5wt%, 1wt%, and 3wt% CeO2). The composite membranes exhibited very similar proton conductivities (~35mS/cm) and hydrogen crossover (~1 mA/cm2) as Nafion®. However, the fluoride emission rate (estimated from accelerated tests) was lowered by more than one order of magnitude upon addition of CeO2 into the Nafion® membrane, suggesting that CeO2 nanoparticles have potential to enhance membrane durability.