Accelerated testing of polymer electrolyte membranes under open-circuit voltage conditions for durable proton exchange membrane fuel cells

Nafion NRE212, Nafion HP, and a hydrocarbon-based membrane were used in an accelerated open-circuit voltage (OCV) test to examine their oxidative stability. The catalyst layer and the gas permeability were analyzed to apply the same experimental conditions for each electrolyte membrane. The accelerated OCV test was conducted for ∼800 h, and the states of the membrane electrode assembly (MEA) were investigated by measuring the electrolyte membrane resistance, cyclic voltammograms, and linear sweep voltammograms with respect to time. Typically, the sulfonated poly(arylene ether), which has a low oxidative stability, showed the best performance in the OCV test, followed by the Nafion HP membrane and Nafion NRE212 membrane. The inherent oxidative durability of the electrolyte membrane and the gas permeability likely play a crucial role in the oxidative stability during MEA operation. The results further confirmed that the gas permeability affects the stability of the electrode in the catalyst layer.