A highly durable thin-film assembled membrane for efficient gas crossover suppression in anion exchange membrane water electrolysis

Zirfon diaphragms, widely employed in alkaline water electrolysis (AWE) systems, exhibit excellent mechanical robustness; however, their highly porous structure results in poor gas-barrier properties, rendering them unsuitable for high current density operation in anion exchange membrane water electrolysis (AEMWE). In this work, we developed a thin-film-assembled (TFA) membrane by laminating commercial Zirfon with ultrathin polymer membranes, including para-polybenzimidazole (p-PBI) and poly(dibenzyl-co-terphenyl piperidinium) (PDTP). This multilayer architecture significantly reduced hydrogen permeance compared with Zirfon alone (over tenfold reduction) while maintaining high mechanical integrity. Consequently, the TFA membrane demonstrated outstanding AEMWE cell performance, achieving 3,926 mA cm⁻² at 2.0 V with PGM catalysts, and 2,261 mA cm⁻² at 2.0 V using PGM-free catalysts in 30 wt% KOH at 90 °C. Furthermore, the TFA membrane showed remarkable durability, stably operating at 2.0 A cm⁻² for 1,000 h and 2.5 A cm⁻² for 670 h at 90 °C without interruption. This study highlights the effectiveness of Zirfon–polymer hybrid stacking as a membrane design strategy for achieving high current density, durable AEMWE operation.