Research progress of the porous membranes in alkaline water electrolysis for green hydrogen production

Hydrogen, as an energy carrier, has attracted extensive attention due to its pollution-free, high calorific value and diverse sources. Among various hydrogen production methods, alkaline water electrolysis (AWE) stands out, where the membrane, also named as separator, is one of key components in the AWE electrolyzers, because it determines the produced gas purity, equipment safety and electrolysis efficiency. This paper presents a comprehensive review on the progress of porous membrane applied in AWE for green H₂ production. The focus lies in understanding the fundamental principles of AWE porous membrane and summarizing the current status and research advances in this field. The critical roles of porous membrane in enhancing product gas purity and mitigating energy consumption within AWE cells are highlighted. Overview of membrane materials of two major categories (asbestos and non-asbestos membranes) applied in AWE systems is summarized. The future development trends of high temperature, high pressure and large current density in AWE technology are presented, and the diversified hydrophilic modification methods, including refining membrane pore structures, enhancing membrane temperature resistance and developing cost-effective fabrication processes are also addressed. In short, this paper provides valuable perspectives for development of porous membrane of AWE electrolyzers for large-scale green H₂ production.