Experimental study on Pt degradation characteristics of proton exchange membrane fuel cell with different flow fields under dynamic loading conditions

The flow field structure has a significant influence on the water-electricity-heat state and mass transfer inside the fuel cell, which in turn affects the Pt degradation under dynamic loading conditions. In this paper, the square wave voltage cycle is used to simulate the dynamic loading conditions, and the degradation characteristics of Pt catalysts in three typical fuel cells with cathode parallel flow field, serpentine flow field and foam flow field, are experimentally studied by combing electrochemical performance measuring and morphology characterization. The results show that the fuel cell with parallel flow field is prone to water flooding and local gas shortage under dynamic loading conditions, which lead to carbon support corrosion and Pt catalyst sintering, while only Ostwald ripening and Pt precipitation in the membrane occur in the fuel cells with serpentine and foam flow fields. Therefore, the Pt degradation in the fuel cell with parallel flow field is more severe. Compared with the serpentine flow field, the foam flow field has no rib structure which is easy to accumulate water; thus, the Pt degradation rate is further reduced. This research enables comprehensive understanding of Pt degradation, which can provide theoretical guidance for design and operation of long-life fuel cells.