Alkaline Stable and Mechanically Robust Interpenetrating Polymer Network Type Anion Exchange Membrane for High‐Performance Alkaline Electrolyzer

Degradation of anion exchange membranes (AEMs) in alkaline medium is an issue to be resolved for the durability and performance of anion exchange membrane water electrolyzers (AEMWEs). This study presents the development of interpenetrating polymer network type anion exchange membranes (IPN-AEMs) with improved alkaline stability, contrived with varying thicknesses (110, 80, and 40 µm) for alkaline and seawater electrolysis. Among the fabricated membranes, IPN-AEM-40 demonstrated superior physicochemical properties, including water uptake (33%), ion exchange capacity (1.3 meq g^-1), and ionic conductivity (5.5 × 10^-2 S cm^-1). The alkaline stability tests of IPN-AEM-40 in 5 m KOH at 80 °C indicated 75% retention of ionic conductivity over 90 days, with nucleophilic substitution identified as the predominant degradation pathway, corroborated by FT-IR spectroscopy and computational analysis. Electrolysis performance evaluation revealed a current density of 850 mA cm^-2 at 2 V in 1 m KOH at 80 °C, along with optimal seawater electrolysis with a current density achieving 600 mA cm^-2 at 80 °C. These findings underscore the potential of IPN-AEM-40 for high-performance and durable hydrogen generation with anion exchange membrane water electrolyzers (AEMWEs).