The effects of cathode platinum loading and operating backpressure on PEMFC performance

By combining theoretical calculations with experimental data, this study quantified the effects of both cathode Pt loading and operating backpressure on polymer electrolyte membrane fuel cell (PEMFC) performance, in terms of the kinetic, ohmic and transport losses. Pt loadings of 0.1, 0.2 and 0.4 mg·cm^-2 were investigated at backpressure values of 100, 150 and 200 kPa, respectively. The results indicate that, under all conditions, the kinetic, ohmic and transport losses all increased with the increase in current density. However, under the equivalent backpressure the transport loss of a PEMFC decreased with the increase of Pt loading. It was also found that increasing the operating backpressure improved the cell performance, and this enhancement in performance was more pronounced at a lower Pt loading. This result indicates an appropriate increase in operating backpressure should benefit the performance of a low-Pt loading PEMFC. Finally, the mechanism responsible for the observed phenomena was discussed. This study is expected to be helpful in the design and performance optimization of PEMFCs with low or ultra-low Pt loadings.