Regulating Water Molecules via Bioinspired Covalent Organic Framework Membranes for Zn Metal Anodes

Abstract The Zn metal anode in aqueous zinc‐ion batteries (AZIBs) faces daunting challenges including undesired water‐induced parasitic reactions and sluggish ion migration kinetics. Herein, we develop three‐dimensional covalent organic framework (COF) membranes with bioinspired ion channels toward stabilized Zn anodes. These COFs, featured by zincophilic pyridine‐N sites, enable effective regulation of water molecules at the anode‐electrolyte interphase. Systematic experimental analysis and theoretical simulations reveal the optimized COF‐320N membrane functions as ion pumps, accordingly facilitating Zn 2+ transport and inhibiting direct contact between Zn anode and free water molecules. Consequently, the bio‐inspired strategy achieves improved Zn 2+ transference number (0.61), rapid de‐solvation kinetics, and suppressed hydrogen evolution. The assembled Zn||MnO 2 pouch cell integrated with COF‐320N membrane exhibits favorable electrochemical performances. Such a bioinspired concept for optimizing Zn anodes opens new pathways in developing advanced energy storage devices.