Construction of 3D porous zinc anode coated with FCTF protective layer through in-situ iodine etching strategy to enable highly stable zinc battery

In recent years, aqueous zinc-ion batteries have received widespread attention in the field of energy storage due to their low cost, high safety, and high theoretical capacity. However, the zinc anode presents challenges such as dendrite growth and side reactions, which result in poor reversibility and failure of the battery. Herein, 3D porous zinc anodes coated with fluorinated covalent triazine framework (FCTF) layer are prepared via a surface coating-assisted iodine etching strategy. The iodine-etched 3D porous zinc anode has a high specific surface area and can effectively decrease the local current density on the surface of the zinc anode, thereby promoting uniform zinc deposition. In addition, theoretical calculations indicate that the FCTF has firm fluorine-containing nanochannels and abundant zincophilic sites (N atoms). As a protective layer, it can provide a strong physical barrier and Zn2+ transport channels, thereby inhibiting the occurrence of side reactions. Benefiting from the synergistic effect of the FCTF protective layer and 3D porous zinc anode, the 3D Zn@FCTF symmetric battery can achieve a cycle life of 3600 hat 1 mA cm- 2. Moreover, the initial discharge capacity of the 3D Zn@FCTF//CVO battery at a current density of 1 A/g is as high as 402.2 mAh/g. This work presents a novel approach to enhance the stability of zinc-ion batteries.