The effects of temperature on transport phenomena in phosphoric acid doped polybenzimidazole polymer electrolyte membrane fuel cell

An energy analysis for the H₃PO₄ (phosphoric acid) doped PBI (polybenzimidazole) polymer electrolyte membrane fuel cell depending on the operating temperature is aimed in this study. In line with this aim, the relation of heat sources from electrochemical reaction, ionic and electronic current with the cell operating temperature is analyzed in detail for both anode catalyst layer and cathode catalyst layer. In addition, effect of the cell operating temperature on species and charge in the fuel cell is indicated. For this analysis, a single phase and two dimensional numerical model is developed with the help of COMSOL Multiphysics 4.2a software under the conditions of the different cell operating temperatures (from 120 to 180 °C stepping by 20 °C) and a constant acid doping level (6.75 RPU H₃PO₄/PBI). The results bring out that the irreversible and reversible entropic heat sources are more dominant than the joule heating source and the heat source by conduction at the cathode catalyst layer. The molar concentrations of all species through all layers are also presented. - Highlights: • Performance of phosphoric acid doped PBI PEMFC. • The effect of temperature on transports of heat, species and charge in HT-PEMFC. • The heat sources released from the cathode catalyst layer are investigated. • The temperatures through MEA increase linearly towards the cathode from the anode.