Modeling Electrolyte Composition Effects on Anion-Exchange-Membrane Water Electrolyzer Performance

Abstract

Anion-exchange membrane (AEM) electrolyzers are an attractive alternative for hydrogen production due to the potential stability and activity of non-precious metal catalysts in alkaline environments. Recently, AEM electrolyzers have been demonstrated using various membranes, ionomers, porous-transport layers, and catalysts (1). The influence of these materials and their properties on AEM electrolyzer performance, however, is underdeveloped. Furthermore, recent studies have shown (2) and hydrogen-evolution reaction kinetics (3), offering additional routes to decreasing cost and reducing operating voltage. In this work, we use a coupled, nonisothermal, multiphase model of an AEM electrolyzer to understand the role of material properties, transport phenomena, and reaction kinetics in improving device pformance. We use the model to identify performance bottlenecks through applied voltage breakdowns (AVBs) and provide guidance for next-generation electrolyzer materials and designs by evaluating sensitivity to membrane and catalyst-layer properties. Finally, we explore the effects of various electrolyte solution feeds and operating paradigms on cell performance, with a particular interest in the influence of ion transport on reaction kinetics. Acknowledgements This work was funded under the HydroGEN Consortium, by the Office of Energy Efficiency and Renewable Energy (EERE), of the U.S. Department of Energy under contract number DE-AC02-05CH11231. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internship (SULI) program. This work was also supported in part by Workforce Development & Education at Berkeley Lab. We thank Sanjeev Mukerjee, Ian Kendrick, Yu Seung Kim, and Dongguo Li for helpful discussions. References I. Vincent and D. Bessarabov, Renewable and Sustainable Energy Reviews, 81, 1690 (2018).H. Ito, N. Kawaguchi, S. Someya, T. Munakata, N. Miyazaki, M. Ishida and A. Nakano, International Journal of Hydrogen Energy, 43, 17030 (2018).Q. Jia, E. Liu, L. Jiao, J. Li and S. Mukerjee, Current Opinion in Electrochemistry, 12, 209 (2018).