Coated stainless steel as bipolar plate material for anion exchange membrane fuel cells (AEMFCs)

Low-temperature anion-exchange membrane fuel cells (AEMFCs) are gathering increased attention because they facilitate the use of non-precious metal catalysts, which might drastically reduce costs compared to low-temperature proton exchange membrane fuel cells (PEMFCs). Metallic, e.g., stainless steel, bipolar plates (BPPs) present a cost-efficient solution for this type of cell. However, anodic film formation at high positive potentials (approx. +1.5 V vs. RHE) on uncoated metals/stainless steels leads to high interfacial contact resistance (ICR) of the BPP once exposed to such a potential. A potential of +1.5 V vs. RHE is commonly reached under local and global hydrogen starvation, which rules out the use of uncoated metals in AEMFCs. We have investigated the ICR change and oxide film formation of several materials under simulated fuel cell operating conditions and found that suppression of anodic film formation and, in turn, low ICRs can be achieved by carbon coating of stainless steels. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.