Modeling and Investigation of Carbon Loss on the Cathode Electrode during PEMFC Operation

Severe carbon loss phenomena, such as partial hydrogen starvation and start-up, have been investigated in previous works. Even for short times, these acute situations can be fatal, and some methods have been suggested to mitigate carbon oxidation and improve proton exchange membrane fuel cell (PEMFC) durability. By comparison, the rate of carbon loss is low during an ordinary PEMFC operation. Although less severe than for hydrogen starvation and start-up, the impact is still large enough so that the cell performance degrades markedly after a long-term operation. In this work, carbon loss during a PEMFC operation is investigated with a physical model. These results quantify the effects that cell voltage, activity for oxygen reduction, humidity, and temperature have on the rate of carbon loss. More rapid kinetics for oxygen reduction promotes carbon loss by lowering the solution potential at the fuel cell cathode.