Abstract:
Polymer electrolyte fuel cells (PEFC) finds a suitable application in automotive vehicles as the prime mover. During its lifetime operation, a PEFC is subjected to various types of loading conditions, most of which is cyclic in nature. However, cyclic loading has been found to adversely affect the Pt catalyst cathode of a PEFC by dissolution and agglomeration of the Pt particles. It results in reduction of active electrochemical surface area, and hence reduced performance of the PEFC. In the present study, the degradation estimation of Pt catalyst cathode of a PEFC under various cyclic load profiles has been studied. Rectangular and trapezoidal load profiles have been selected with different duty cycles. The degradation estimation is based on the Pt agglomeration model, which can predict the electrochemical surface area (ECSA) at the end of set number of cycles. It was found that different voltage profile can affect the ECSA degradation in the PEFC. Degradation effect is evaluated based on the change in the electrochemical surface area, which renders to performance degradation. The Ostwald ripening effect for the Pt particles with operating time is also studied. It was concluded that Ostwald ripening lead to growth of Pt particles, which further inversely affect the ECSA and causes performance degradation.