Precise void-structure regulation of polysulfone/EVOH composite membranes via interfacial hydrogen-bond cross-linking for alkaline water electrolysis

Green hydrogen is the largest contributing factor to the growth of the hydrogen energy industry, with alkaline water electrolysis (AWE) being a leading manufacturing process for its large-scale fabrication. However, commercial membranes exhibit insufficient hydrophilicity and poor gas barrier properties, limiting AWE efficiency and safety. This work develops a high-performance composite membrane with low area resistance, excellent gas barrier and high mechanical strength. By incorporating hydrophilic EVOH into PSU and applying pre-evaporation in phase inversion, a hydrogen-bonded network is constructed and pore structure is regulated. The optimized PEZ-10 membrane shows porosity of 61.23%, water contact angle of 48.33°, area resistance of 0.153 Ω cm 2 , bubble point pressure of 5.38 bar and tensile strength of 44 MPa. It achieves 1714 mA cm −2  at 2 V and operates stably for over 100 h at 500 mA cm −2 , providing a feasible strategy for high-performance AWE membranes in large-scale green hydrogen production.