Uniform Nanoporous Zirconia Composite Membrane Enabling High-Performance Alkaline Water Electrolysis

Zirconia-based membranes typically face a trade-off between ionic transport and gas barrier performance, limiting their effectiveness in alkaline water electrolysis (AWE), where low area resistance, high bubble-point pressure, and long-term stability are essential. Here, we report a novel method for fabricating a nanoporous composite membrane. Yttria-stabilized zirconia nanoparticles (YSZNPs) were uniformly dispersed into a sol-state polybenzimidazole (PBI) matrix via a one-pot sol-gel process. The resulting membrane exhibited a sponge–like, uniform nanoporous morphology with an ultrahigh porosity of ~ 85%. Yet, maintains an excellent bubble-point pressure (> 25 bar). Strong interfacial interactions between the YSZNPs, hot PA and the PBI chains promote uniform nanoparticle dispersion and improve the hydrophilicity of the inorganic domains. The synergistic multi-pathway structure facilitates continuous hydroxide ion (OH⁻) migration. In AWE tests, the membrane delivers a high current density of 13.1 A·cm ^–2 at 2.0 V. Reinforcement with a polyphenylene sulfide (PPS) mesh enables stable operation for 7000 h in AWE, and the membrane performs reliably in a large-area single-cell stack. This work introduces a scalable route to gel-state ceramic–polymer membranes for high-efficiency hydrogen production.