Three-Dimensionally Fibrillated Inorganic Composite Anion Exchange Membranes for Ampere-Scale Hydrogen Production

Abstract

Hydroxide-induced degradation and swelling of organic anion exchange membranes (AEMs) fundamentally limit the advancement and industrialization of alkaline hydrogen production. Here, we present a free-standing inorganic AEM comprising 90 wt % layered double hydroxides within a three-dimensionally fibrillated polytetrafluoroethylene scaffold. The membrane achieves zero swelling, suppressed hydrogen crossover, and a low area-specific resistance of 0.089 Ω cm2 while remaining stable for 1344 h in 1 M and 30 wt % KOH at 80 °C, under which commercial polymeric membranes fail rapidly. The confined hydrogen-bond network within layer double hydroxide galleries promotes Grotthuss-dominated OH– transport as supported by ab initio molecular dynamics. The membrane sustains 1 A cm–2 operation for 550 h in AEM water electrolyzers and 425 h in alkaline water electrolyzers, establishing a durable inorganic AEM platform for alkaline hydrogen production and related electrochemical energy technologies.