Quasi Three-Dimensional Modelling of the PEM Fuel Cell: Comparison of the Catalyst Layers Performance

The results of the first quasi three dimensional modelling of a polymer electrolyte membrane fuel cell with meander-like gas channels are reported. The model resolves the catalyst layers and takes into account feed gas consumption in the channels. The results show that in both catalyst layers the rate of electrochemical reaction in front of the channels is higher, than in front of the current collectors. The overpotential is almost constant across the cathode catalyst layer and varies rapidly (exponentially) across the anode catalyst layer. A current on the anode side is produced in a thin sub-layer adjacent to the membrane, where the overpotential is close to its maximum value. A simple formula for optimal thickness of the anode catalyst layer is derived and compared with numerical results.