Zincophilic MOF Protective Layer for Stable Zinc Anodes in Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are under the spotlight due to their substantial potential, abundant natural resources, inherent safety, and high specific capacity. However, uncontrollable zinc dendrite growth and side reactions on the zinc surface hinder the application of ZIBs. In this article, a uniform copper-based metal-organic frameworks (MOFs) coating layer was fabricated on a zinc metal surface (CuZIF@Zn) to serve as a protective interface. Synchrotron X-ray techniques were employed to study the electrode structure before and after cycling. With its special structure, the MOF interfacial layer acts as an effective barrier layer to isolate the zinc anode from water molecules and electrolyte, thereby suppressing interfacial side reactions and passivation. Additionally, the abundance of zincophilic sites in the CuZIF layer ensures uniform deposition of Zn²⁺ while effectively inhibiting the growth of dendritic structures. Consequently, the CuZIF@Zn//CuZIF@Zn symmetric batteries exhibited cycling stability over 1000 cycles at 1.0 mA cm^-2, attributed to the protective layer. Furthermore, a full cell incorporating an MnO₂ cathode maintained 189 mAh g^-1 over 700 cycles, demonstrating remarkable long-term cycling performance.