PEMFC-Performance of Unsupported Pt-Ni Aerogel Cathode Catalyst Layers under Automotive-Relevant Operative Conditions

Abstract

Unsupported, Pt-based electrocatalysts hold great potential for implementation in polymer electrolyte membrane fuel cell (PEMFC-) cathodes owing to their enhanced durability under startup/shutdown conditions entailing high potential excursions. Among such materials, the recently developed Pt-Ni aerogel consisting of tridimensional nanochains of interconnected nanoparticles has already been shown to feature an initial PEMFC–performance comparable to that of C-supported Pt-nanoparticles (Pt/C) along with a much better startup/shutdown durability. However, all PEMFC characterization of this materials has been carried out at 80 °C and using fully humidified gases, and its behavior under more demanding conditions concomitant to its potential implementation for automotive applications remains unexplored. Thus, in this work aerogel catalyst layers (CLs) are characterized under a wide range of temperatures and relative humidities, as well as submitted to fast current up-transients. These extensive tests showed that the performance of the aerogel CLs is comparable to that of a commercial Pt/C benchmark, except at high current densities and low temperatures at which the thin aerogel layers suffer from a low water storage capacity.