Improving PEMFC Performance Using Low Equivalent Weight PFSA Ionomers and Pt-Co ∕ C Catalyst in the Cathode

Abstract

The effects of lower equivalent weight (EW) perfluorosulfonic acid (PFSA) ionomers and catalyst on the cathode performance of proton exchange membrane fuel cells (PEMFCs) were investigated at two atmospheric pressure operating conditions: low temperature/high relative humidity (RH), RH, and high temperature/low RH, RH. Cell voltage at a current density of was used for the performance comparison. The optimized content in the electrode changed with the ionomer EW, from 32% for 1100 EW Nafion, 28% for 920 EW Nafion to 25% for a developmental PFSA 800 EW ionomer. Compared to 1100 EW Nafion, 800 EW ionomer significantly improved the cell performance by 39 mV at RH; however, at RH, its effect was not apparent. The introduction of catalyst into the cathode increased the cell performance by at RH, which was much higher than a performance improvement at RH. Compared to electrodes made of and Nafion 1100 EW, the combination of 800 EW Ionomer and catalyst resulted in a cell voltage increase at RH and a cell voltage increase at RH.