Improvement in the diffusion characteristics of low Pt-loaded electrodes for PEFCs

Low Pt loading electrodes have been obtained by the direct mixing of electrocatalyst and Nafion® ionomer (for catalyst layer) and by the introduction of an intermediate hydrophobic carbon layer to optimize gas distribution. The influence of Teflon® content in the carbon layer has been studied and an optimum content of 20 wt% has been found. The behaviour of the improved electrodes as a function of temperature (70–95 °C) and gas (H2 and air) pressure (1–5 bar) has been evaluated in a 50 cm2 single cell. In air operation at 5 bar absolute pressure and 95 °C a maximum in the power density of about 450 mW cm−2 has been obtained.