Ion‐Selective Microporous Membranes via One‐Step Copolymerization Enable High‐Performance Redox Flow Batteries

Abstract Redox flow batteries are a promising solution for grid‐scale energy storage but are constrained by ion‐exchange membranes that struggle to simultaneously achieve high ionic conductivity and effective selectivity against redox‐active species. Traditional nanophase‐separated membranes inherently suffer from trade‐offs between conductivity and selectivity; while emerging microporous polymer membranes typically involve complex synthetic routes and high production costs. Herein, a straightforward, one‐step copolymerization strategy is introduced that integrates rigid nanopore‐forming, hydration‐regulating, and ion‐conductive monomers into microporous membranes with precisely tunable properties. These membranes exhibit interconnected ultra‐microporous channels, providing exceptional dimensional stability, optimized hydration networks, and uniformly distributed ion‐conductive functionalities, thereby facilitating rapid ion transport alongside ion.