Durable, pure water–fed, anion-exchange membrane electrolyzers through interphase engineering
Shujin Hou, Archana Sekar, Yang Zhao, Minkyoung Kwak, Juhyun Oh, Kelvin Kam-Yun Li, Peiyao Wu, Ryan T. Hannagan, Valeria Cartagena, Anthony C. Ekennia, Hui Duan, Michael J. Zachman, Joëlle Fréchette, Gregory M. Su, Balsu Lakshmanan, Yushan Yan, Thomas F. Jaramillo, Shannon W. Boettcher
Abstract
Anion-exchange membrane water electrolyzers (AEMWEs) promise scalable, low-cost hydrogen production but are limited by the electrochemical instability of their anode ionomers. We report interphase engineering using inorganic-containing molecular additives that coassemble with ionomer, enabling pure water-fed AEMWEs to operate with a degradation rate <0.5 millivolt per hour at 2.0 amperes per square centimeter and 70°C-a >20-fold durability improvement. Analysis of different additives and ionomers shows that the stabilization mechanism involves cross-links between metal oxo/hydroxo oligomers and ionomers. Under operation, the inorganic additive enriches, forming an interphase near the water-oxidation catalyst that passivates the anode ionomer against continuous degradation while maintaining mechanical integrity and hydroxide conductivity. This additive-based interphase-engineering strategy provides a path to durable AEMWEs that operate without supporting electrolytes and is adaptable across diverse catalysts and ionomers for electrochemical technologies.