Positioning of a High-Performance Anion-Exchange Membrane Material for Alkaline Water Electrolysis: A White Paper

Energy security is a major concern for sustainable development. The traditional use of fossil fuels has significant environmental impacts, limited availability, and geopolitical implications. In this context, green hydrogen emerges as a promising alternative. The generation of green hydrogen via alkaline water electrolysis offers great potential, particularly by eliminating the need for platinum group metal catalysts. However, the stability of membrane separators remains a significant challenge due to the highly alkaline and oxidative environment, which favors nucleophilic substitution reactions. Over the past decade, substantial progress has been made in improving membrane stability for alkaline water electrolysis. Nevertheless, several critical issues remain unresolved. This review highlights key advancements in membrane design, fabrication, and performance optimization for next-generation membranes in alkaline water electrolysis applications. We comprehensively examine membrane developments, from polybenzimidazole-based systems and recently introduced superacid catalysis, to ring-opening metathesis polymerizations and traditional polystyrene-based membranes. The review emphasizes their structural evolution and the essential modifications required to achieve outstanding performance and stability. It aims to provide readers with a solid foundation in polymer synthesis and design for the development of advanced membrane materials.