A two-phase model of an intermediate temperature PEM fuel cell

A two-phase model of an intermediate temperature (120–200 °C) proton exchange membrane (PEM) fuel cell is presented. This model is an improvement on our previous intermediate temperature models, in that it accounts for two phase effects due to gas solubility in the phosphoric acid/polybenzimidazole (PBI) electrolyte, and considers aqueous phase electrochemical reactions. The model accounts for all polarization and transport phenomena, and exhibits a good fit with experimental data in the temperature range (150–170 °C). Parametric results are also presented, to investigate the dependence of the fuel cell performance on membrane doping level, catalyst activity, and transport properties of dissolved gases in the electrolyte medium. Results indicate that significant transport limitations exist at both electrodes, where catalyst utilization is between 0.1% and 1%. Alternative doping agents to phosphoric acid are suggested, as well as the need for more advanced catalyst deposition techniques.