Document Type
Article
Abstract
Anion exchange membrane water electrolyzers (AEMELs) have recently received significant attention due to their potential advantages over proton exchange membrane electrolyzers (PEMELs). However, some AEMELs feed an aqueous salt solution to the cell where PEMELs typically feed deionized (DI) water. DI water is preferred to keep the system and maintenance costs low. Because of this, many AEMEL researchers report performance both in the salt solution (typically KOH) and DI water. However, the methodology for switching between KOH and DI water is often poorly defined, and it is unclear what impact the residual salt has on cell performance after switching from salt to DI water. Having a fully deionized environment is important because the presence of salts in the water feed increase the effective electrochemical surface area of the catalyst in the three-dimensional electrode and residual salt remaining after switching to DI water feed can have a misleading transient effect on cell performance. This paper focuses on understanding the transition from KOH to DI water testing in AEMELs. It is shown that when switching from salt to DI water feed, a large volume of DI water must be fed over several hours to achieve true DI-water performance. It is also shown that starting AEMELs from the beginning with DI water feed (without any KOH ever being fed to the cell) results in better cell durability. Lastly, a cell is demonstrated having operated exclusively on DI water at 1.0 A cm(-2) for 500 h at an operating voltage of ca. 2 V and a low degradation rate.
Digital Object Identifier (DOI)
Publication Info
Published in Journal of the The Electrochemical Society, Volume 169, 2022, pages 044526-.
Rights
© 2022 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.
APA Citation
Noor Ul Hassan, Zheng, Y., Kohl, P. A., & Mustain, W. E. (2022). KOH vs Deionized Water Operation in Anion Exchange Membrane Electrolyzers. Journal of the Electrochemical Society, 169(4), 044526–044526. https://doi.org/10.1149/1945-7111/ac5f1d