Recent development in degradation mechanisms of proton exchange membrane fuel cells for vehicle applications: problems, progress, and perspectives

Due to its zero emissions, high efficiency and low noise, proton exchange membrane fuel cell (PEMFC) is full of potential for the application of vehicle power source. Nonetheless, its lifespan and durability remain multiple obstacles to be solved before widespread commercialization. Frequent exposure to non-rated operating conditions could considerably accelerate the degradation of the PEMFC in various forms, thus reducing its durability. This paper first analyses degradation mechanisms of PEMFCs under typical automotive operating conditions, including idling, startup-shutdown, dynamic loads, and cold start. The corresponding accelerated stress testing methods are also discussed. Then, as the impurities existed in the reaction gas source and generated from the degradation of the PEMFC itself may occur under all automotive conditions, the degradation mechanisms caused by impurity contamination are classified and reviewed in detail. After that, the techniques proposed by researchers to enhance the durability of PEMFCs are presented from four aspects: membrane electrode assembly (MEA) materials, bipolar plates and flow fields design, stack assembly, and cell control strategies. The challenges in the field and the prospects for the future are summarized and analyzed at the end. The aim of this work is to provide guidelines for improving the durability of PEMFCs in vehicle applications.