Degradation Study on MEA in H[sub 3]PO[sub 4]∕PBI High-Temperature PEMFC Life Test

In this paper, ( continuous and intermittent) high-temperature proton exchange membrane fuel cell (PEMFC, phosphoric acid-doped polybenzimidazole system, ) life test was performed without humidification at ; constant current (at ) performance and polarization curves were recorded. Electrochemical and physical characterizations were applied to investigate the degradation of the membrane electrode assembly (MEA). The results showed that the constant current performance started to reduce with a rate of after about activation. Surface area loss of the cathode platinum due to agglomeration was detected by cyclic voltammetry and transmission electron microscopy. A slight increase of internal resistance of the single cell due to leaching was found by electrochemical impedance spectroscopy and energy dispersive X-ray analysis. permeability of MEA increased during the last intermittent test because of appearing of cracks, that were detected by linear sweep voltammetry and scanning electron microscopy. These results suggested that catalyst agglomeration and leaching from catalyst layers contributed to the performance degradation of the MEA during the life test, and mechanical properties degradation of membrane impacted badly the lifetime of the single cell.