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Degradation characteristics of membrane electrode assembly under drive cycle test protocol

ABSTRACT One of the key factors determining the lifetime of proton exchange membrane fuel cell (PEMFC) is the degradation and eventually the failure of membrane electrode assembly (MEA). To assess the long-term durability of MEA in fuel cells for vehicular applicatoin, this study adopted the accelerating technique using drive cycle test protocol developed by Chinese NERC Fuel Cell & Hydrogen Technology. The protocol includes starts/stops, idling, and acceleration, simulating major degradation processes in real automobile application. After 900 h of accelerated test, MEA’s performance declined from the initial 0.65 V to 0.58 V@500 mA cm−2, dropping by more than 10% and giving an average voltage decay rate of 70 μV h−1. To examine the underlying mechanisms for the degradation, post-mortem analyses such as X-ray photoelectric spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDX) were carried out for the MEA before and after 900 h drive cycle test. The post-mortem analyses indicate that the thinning of the electrolyte membrane at H2 outlet region is the decisive factor leading to the end-of-life of PEMFC, and the Pt catalysts loss and microstructural damage of MEA are the decisive factors for the performance degradation and stability deterioration of PEMFC.