Fuel starvation in proton exchange membrane fuel cell included carbon corrosion: Multiphysics modeling study

Fuel starvation considers one of the major destructive of performance inside proton exchange membrane fuel cell (PEMFC) leading to depletion of gas reactant, potential reversal, and speed up of carbon corrosion process on the cathode catalyst layer. In this study, a three-dimensional multiphysics model was introduced to investigate the relation between fuel starvation, performance reduction, and carbon corrosion on catalyst layer. In this model, an integration between mass transportation of reactant gases (hydrogen and oxygen), carbon corrosion reaction, and Butler Volmer Kinetics was done to study fuel starvation state during startup/shutdown process. The severity of fuel starvation was represented by variation on gas reactant and relative humidity, that have direct affect on gas transportation resistance with accumulation of water on the electrodes. Simulation results showed an increasing on cathode potential exceeding 0.9–1.0 V due to fuel starvation state, leading to accelerate the carbon corrosion process with redistribution of current density. The corrosion rate speeded up to 2–3 times comparing to normal conditions, leading to losing of carbon surface area with detaching of Pt particles and reduction cell voltage. Simulation results with experimental data were validated for polarization with voltage drop as well as for corrosion rate, there were revealed a high agreement with confirmation of proposed model. The finding was provided mechanistic understanding of the relation between fuel starvation, current density, and carbon corrosion of catalyst layer, present valuable steps to improve the operation conditions and performance enhancing of PEMFC.