Carbon-Support Requirements for Highly Durable Fuel Cell Operation

Abstract

Owing to its unique electrical and structural properties, high surface area carbon has found widespread use as a catalyst support material in proton exchange membrane fuel cell (PEMFC) electrodes. The highly dynamic operating conditions in automotive applications require robust and durable catalyst support materials. In this chapter, carbon corrosion kinetics of commercial conventional-carbon-supported membrane electrode assemblies (MEAs) are presented. Carbon corrosion was investigated under various automotive fuel cell operating conditions. Fuel cell system start/stop and anode local hydrogen starvation are two major contributors to carbon corrosion. Projections from these studies indicate that conventional-carbon-supported MEAs fall short of meeting automotive the durability targets of PEMFCs. MEAs made of different carbon support materials were evaluated for their resistance to carbon corrosion under accelerated test conditions. The results show that graphitized-carbon-supported MEAs are more resistant to carbon corrosion than nongraphitized carbon materials. Fundamental model analyses incorporating the measured carbon corrosion kinetics were developed for start/stop and local hydrogen starvation conditions. The combination of experiment and modeling suggests that MEAs with corrosion-resistant carbon supports are promising material approaches to mitigate carbon corrosion during automotive fuel cell operation.