Covalent Organic Framework Membranes for Fast Anion Transport via Hydrogen Bond Networks

Abstract In recent years, anion exchange membranes (AEMs) have garnered considerable attention due to their pivotal roles in energy applications, including fuel cells, batteries, and electrolyzers. However, enhancing hydroxide (OH⁻) ion conductivity in these membranes remains challenging. Here, the design of covalent organic framework (COF) membranes with tailored hydrogen bond networks is reported to facilitate rapid OH⁻ ion transport. Hydrazone‐linked COF membranes with varying hydroxyl group contents are synthesized to modulate the continuity of hydrogen bond networks. The COF membranes exhibiting the most continuous networks achieve a remarkable OH⁻ conductivity of 263.14 mS cm⁻¹ at 80 °C. This work provides fundamental insights into anion transport mechanisms and establishes COFs as promising materials for advanced AEM applications.