Corrosion of structural components of proton exchange membrane water electrolyzer anodes: A review

Proton exchange membrane (PEM) water electrolysis is one of the low temperature processes for producing green hydrogen when coupled with renewable energy sources. Although this technology has already reached a certain level of maturity and is being implemented at industrial scale, its high capital expenditures deriving from the utilization of expensive corrosion-resistant materials limit its economic competitiveness compared to the widespread fossil fuel-based hydrogen production, such as steam reforming. In particular, the structural elements, like bipolar plates (BPP) and porous transports layers (PTL), are essentially made of titanium protected by precious metal layers in order to withstand the harsh oxidizing conditions in the anode compartment. This review provides an analysis of literature on structural element degradation on the oxygen side of PEM water electrolyzers, from the early investigations to the recent developments involving novel anti-corrosion coatings that protect more cost-effective BPP and PTL materials like stainless steels.