Azulene‐Copolymerized Polybenzimidazole for High‐Performance Anion Exchange Membranes Water Electrolysis

Abstract

Anion exchange membrane water electrolysis (AEMWE) represents a compelling pathway to green hydrogen, bridging the gap between the low cost of alkaline electrolyzers and the high efficiency of proton exchange membrane systems. Despite its potential, the deployment of AEMWE is severely constrained by inadequate membrane performance. To address this bottleneck, we develop a novel polybenzimidazole framework incorporated with strongly polarized azulene units. By reducing the bandgap and tailoring the electronic structure, the azulene moieties induce robust dipole–dipole and cation‐dipole interactions that foster confined yet well‐connected ion‐conducting domains—facilitating superior ion transport while maintaining excellent alkaline stability. The resulting membranes exhibit impressive OH − conductivity of up to 121 mS cm − 1 at 80°C, favorable dimensional stability, and mechanical robustness. When evaluated in AEMWE cells, as‐fabricated membranes deliver a current density of 1.92 A cm − 2 at 2.0 V in 1.0 M KOH and show continuous operation for more than 1900 h at 0.5 A cm − 2 at 60°C, demonstrating favorable balance between ion transport and operational durability. These findings offer a transformative strategy for engineering highly conductive, polarized AEMs, significantly advancing the frontier of durable and efficient AEMWE technologies.