A rapid mechanical durability test for reinforced fuel cell membranes

An in situ accelerated mechanical stress test (ΔP-AMST) that applies relative humidity (RH) cycling combined with a pressure differential (ΔP) at a high temperature is proposed to accelerate mechanical degradation in all types of reinforced membranes used in fuel cells and obtain mechanical failure in a relatively short time. For validation, ePTFE reinforced membranes are mechanically degraded by RH cycling accelerated by means of a ΔP applied from cathode to anode using a custom designed polycarbonate spacer. Reinforced membrane failure detected by ΔP loss is reached within ∼10 to 10,000 RH cycles using this method, depending on the level of applied ΔP. The ΔP-AMST protocol is hence demonstrated as a fast, economical in situ alternative compared to existing methods for evaluating the mechanical fatigue durability of advanced fuel cell membranes.