A modified cathode catalyst layer with optimum electrode exposure for high current density and durable proton exchange membrane fuel cell operation

Abstract

In proton exchange membrane fuel cells (PEMFCs), polymeric ionomer functions, as the membrane that transports protons and water from one electrode to another and as the catalyst binder and transport channel within the catalyst layer responsible for the electrochemical activity. Here, advanced membrane electrode assemblies (MEAs) of a hierarchical design having excellent durability and fuel cell performance that can be operated under low humidity is developed. The interaction of the pyrochlore Zr2Gd2O7 nanorod (ZrGdNR) with the ionomer used in both the electrolyte and catalyst layer enhances the oxygen reduction reaction and mass transport due to the multivalent property and oxygen vacancies. Open circuit voltage holding test and fluoride ion emission rate reveal the radical scavenger effect of ZrGdNR into the MEA to improve its durability. Compared to the conventional MEA, the modified MEA under 100 and 20% relative humidity delivers 1363 and 767 mW cm−2 of maximum power density, which is 1.8 and 6.3 times higher, respectively. The enormous increase in fuel cell performance and durability due to the 0.29 wt% of ZrGdNR with respect to Pt/C into the catalyst layer may be a promising approach for low catalyst usage in PEMFC having the ability to operate under low humidification. © 2021 Elsevier B.V.