Covalent organic framework film protected zinc anode for highly stable rechargeable aqueous zinc-ion batteries

Although aqueous zinc-ion batteries (ZIBs) have demonstrated great potential for large-scale energy storage, dendrite growth in the Zn metal anode leads to poor electrochemical stability and unsatisfactory cycling life, restricting widespread utilization of ZIBs. Herein, a zincophilic covalent organic framework (COF; TpPa-SO3H) film is fabricated via interfacial reaction to stabilize the Zn anode (TpPa-SO3H@Zn-foil). The sulfonic acid groups on the TpPa-SO3H film coordinate with Zn2+ ions and regulate the uniform deposition of Zn2+ ions to inhibit the dendrite formation. Additionally, the TpPa-SO3H can release abundant protons (H+) and achieve a dynamic equilibrium with OH−, thereby adjusting the desolvation of [Zn(H2O)6]2+ to prevent secondary reactions. This work demonstrates that COF film-coated Zn anodes are a family of promising electrode candidates and provides inspiration to other fields of batteries, such as the material design for separator and electrolyte.