Effect of gas dilution on PEM fuel cell performance and impedance response

In this work, an experimental study of gas dilution on the performance of a polymer electrolyte membrane (PEM) fuel cell was carried out. Impedance spectra were analysed depending on the dilution of either hydrogen or oxygen by nitrogen. By comparison of the impedance spectra obtained, the three loops were attributed to hydrogen oxidation, oxygen reduction and a low frequency diffusion process. Hydrogen oxidation was shown to be more complicated when the anode side was fed by a simulated reforming gas than with the same dilution rate with nitrogen.