Predicting local H₂ starvation in a PEM fuel cell: Origin and materials impact

Carbon-support corrosion is of great concern to MEA durability. We model local H2 starvation induced cathode carbon corrosion in an operating PEM fuel cell and predict when local H2 starvation occurs and how it affects the carbon corrosion rate. We conclude that O2 crossover through membrane controls the total amount of current that goes to carbon corrosion and oxygen evolution at cathode. A membrane with lower O2 permeability allows less O2 crossover and thus less cathode carbon corrosion. The relative rate of carbon corrosion to oxygen evolution has significant implication on mitigating carbon-support corrosion: either making carbon support more corrosion-resistive or enhancing oxygen evolution can greatly reduce carbon loss with oxygen evolution reaction taking up more current. The length and time scales for local H2 starvation to emerge are dependent on the operating conditions. In the realistic range DM permeability has no impact on the occurrence of local H2 starvation.