Mussel-inspired interfaces enable enhanced bubble management and OH− transport in alkaline water electrolysis

Alkaline water electrolysis (AWE) separators face a critical challenge that gas bubble accumulation at electrode-separator interfaces impedes hydroxide-ion (OH − ) transport and limits current density at industrially relevant operating conditions. Conventional sulfonation, while improving hydrophilicity, requires hazardous chemicals. Here, we report a self-assembled polydopamine/polyethyleneimine (PDA/PEI) interface that overcome these limitations through a green, room-temperature process. The co-assembled network achieves ultralow bubble adhesion force (0.005 mN), enabling rapid gas detachment that prevents blocking layer formation, while simultaneously creating amine-rich pathways for enhanced OH − migration. Applied to polyphenylene sulfide (PPS) woven fabric, the modified separator delivers a four-fold increase in current density at 2.0 V with stable operation over 2000 h, and successfully scaling to an industrial 6-cell stack. This bioinspired interfacial engineering strategy provides a sustainable and scalable alternative to conventional chemical modifications for high-performance AWE separators.