Addressing the Challenge of Electrochemical Ionomer Oxidation in Future Anion Exchange Membrane Water Electrolyzers
Jihoon Lim, Jeffrey M. Klein, Seung Geol Lee, Eun Joo Park, Sun Young Kang, Sandip Maurya, William E. Mustain, Shannon W. Boettcher, Yu Seung Kim
Abstract
Hydrogen production through anion-exchange membrane water electrolyzers (AEMWEs) offers cost advantages over proton-exchange membrane counterparts, mainly due to the good oxygen evolution reaction (OER) activity of platinum-group-metal-free catalysts in alkaline environments. However, the electrochemical oxidation of ionomers at the OER catalyst interface can decrease the local electrode pH, which limits AEMWE performance. Various strategies at the single-cell-level have been explored to address this issue. This work reviews the current understanding of electrochemical ionomer oxidation and strategies to mitigate it, providing our perspective on each approach. Our analysis highlights the competitive adsorption strategy as particularly promising for mitigating ionomer oxidation. This Perspective also outlines future directions for advancing high-performance alkaline AEMWEs and other energy devices using hydrocarbon ionomers.