Abstract
Alkaline or hydroxide exchange membrane water electrolysis (HEMWE) is a promising technology for green hydrogen production using platinum group metal-free catalysts and stainless steel, an advantage of alkaline water electrolysis (AWE), and a gasimpermeable membrane, a parallel to proton exchange membrane electrolysis (PEMWE). However, the HEMWE requires supporting electrolytes and there is minimal understanding of their role on the respective reactions. Without SELs, HEMWE performance and durability are worse than PEMWE systems. Herein, consistently feeding potassium hydroxide anolyte, we systematically study the effects of catholyte SELs in HEMWEs including dry vs. wet operation, cation effects, anion effects, and cation/OH ratios on cell potential and stability. We report that (i) hydration of the cathode improves high current density operation by preventing dehydration of the hydroxide exchange membrane (HEM), (ii) there was no correlation between cation type and cell potential, (iii) cell potential and high frequency resistance did not correlate with SEL conductivity, (iv) cathodic carbonate SEL had a significant negative effect on cell performance, (v) increased cation/OH ratio also caused increased cell potentials. Overall, this study concludes that feeding water or potassium hydroxide solution is desirable to improve the AEMWE performance.
| Original language | English |
|---|---|
| Article number | 024510 |
| Journal | Journal of the Electrochemical Society |
| Volume | 169 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2022 |
| Externally published | Yes |
Funding
A.K. gratefully acknowledges funding from the German Fulbright Commission and the Studienstiftung des deutschen Volkes. A.K. thanks the Office for International Education for continuous support during this stay in the US and Prof. Hubert Gasteiger for fruitful discussions. N.D., M.R.G., X.P., A.Z.W., J.C.F., Y.S.K. and G.A. gratefully acknowledge research support from the HydroGEN Advanced Water Splitting Materials Consortium, established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, under Contract Number DE-AC02–05CH11231 (LBNL) and 89233218CNA000001 (LANL). JCF thanks the National Science Foundation (grant DGE1106400) for support. S.M., B.Z. and A.S. also acknowledge Advanced Research Projects Agency-Energy under contract DE-AR000688. The authors would like to thank Nel Hydrogen for supplying titanium porous transport layers.
| Funders | Funder number |
|---|---|
| German Fulbright Commission | |
| National Science Foundation | DGE1106400 |
| U.S. Department of Energy | |
| Advanced Research Projects Agency - Energy | DE-AR000688 |
| Office of Energy Efficiency and Renewable Energy | |
| Los Alamos National Laboratory | |
| Hydrogen and Fuel Cell Technologies Office | 89233218CNA000001, DE-AC02–05CH11231 |
| Studienstiftung des Deutschen Volkes |
