A Self‐Recognition Separator for Ion Management to Customize Selective Zn2+ Channels Toward Dendrite‐Free Zinc Metal Anodes

ABSTRACT Aqueous zinc‐ion batteries (ZIBs) are promising candidates for next‐generation energy storage, but the problems related to Zn dendrites and side reactions severely hinder their practical applications. Herein, a self‐recognition separator based on a Bi‐based metal–organic framework (GF@CAU‐17) is developed for ion management to achieve highly reversible Zn anodes. The GF@CAU‐17 has self‐recognition behavior to customize selective Zn 2+ channels, effectively repelling SO 4 2– and H 2 O, but facilitating Zn 2+ conduction. The inherent properties of CAU‐17 result in the repulsion of SO 4 2– ions while disrupting the hydrogen bond network among free H 2 O molecules, restraining side reactions and by‐products. Simultaneously, the zincophilic characteristic of CAU‐17 expedites the desolvation of [Zn(H 2 O) 6 ] 2+ , leading to a self‐expedited Zn 2+ ion pumping effect that dynamically produces a steady and homogeneous Zn 2+ ion flux, and thereby alleviates concentration polarization. Consequently, a symmetric cell based on the GF@CAU‐17 separator can achieve a long lifespan of 4450 h. Moreover, the constructed Zn//GF@CAU‐17//MnO 2 cell delivers a high specific capacity of 221.8 mAh g −1 and 88.0% capacity retention after 2000 cycles.