Facilitating Rapid OH‐/H2O Transport in Anion Exchange Membranes via Ultra‐Stable Heteroatom‐free Micropores

Abstract

Efficient OH‐ conduction in anion exchange membranes (AEMs) is pivotal for the advancement and industrialization of sustainable electrochemical technologies in alkaline environments, including water electrolysis, fuel cells, and CO2 electroreduction. We here designed AEMs with a novel class of rigid heteroatom‐free micropores (HFMs), engineered at the molecular level to facilitate rapid ionic transport in an ultra‐stable manner. By manipulating monomers, our design strategically controls the torsional angles and energy barriers within the polymeric backbones, creating sub‐nanometer ionic channels that precisely regulate porosity. These hydrophilic micropores significantly enhance the mobility of OH‐/H2O, achieving over a 150% increase in self‐diffusion coefficient compared to commercial AEMs and elevating OH‐ conductivity to a leading 215 mS cm‐1 at 80 °C. Moreover, the robust carbon‐carbon bond construction in HFMs offers the stability that is four orders of magnitude higher under severe alkaline conditions compared to existing wisdoms, with a demonstrated operational lifespan of over 4000 hours. The integration of HFM‐AEMs into water electrolyzers not only supports the use of platinum group metal‐free catalysts but also exhibits exceptional energy efficiency and extended durability, highlighting their substantial potential for wide‐ranging applications in emerging electrochemical technologies.