Two-dimensional CuO nanosheets-induced MOF composites and derivatives for dendrite-free zinc-ion batteries

Uncontrollable dendrite growth and side reactions resulting in short operating life and low Coulombic efficiency have severely hindered the further development of aqueous zinc-ion batteries (AZIBs). In this work, we designed to grow zeolitic imidazolate framework-8 (ZIF-8) uniformly on CuO nanosheets (NSs) and prepared carbon-coated CuZn alloy NSs (CuZn@C NSs) by calcination under H-2/Ar atmosphere. As reflected by extended X-ray absorption fine structure (EXAFS), density functional theory (DFT), and in-situ Raman, the Cu-Zn and Zn-N bonds present in CuZn@C NSs act as zincophilic sites to uniformly absorb Zn ions and inhibit the formation of Zn dendrites. At the same time, CuZn@C NSs hinder the direct contact between zinc anode and electrolyte, preventing the occurrence of side reactions. More impressively, the symmetric cells constructed with CuZn@C NSs anodes exhibited excellent zinc plating/exfoliation performance and long life cycle at different current densities with low voltage hysteresis. In addition, low polarization, high capacity retention, and long cycle life over 1000 cycles at 5 A.g(-1) were achieved when CuZn@C NSs were used as anodes for CuZn@C/V2O5 full cells.

Automated summary

The growth of zeolitic imidazolate framework-8 (ZIF-8) on CuO nanosheets (NSs) and the preparation of carbon-coated CuZn alloy NSs (CuZn@C NSs) under H-2/Ar atmosphere have been used to tackle the issues hindering the development of aqueous zinc-ion batteries (AZIBs). The Cu-Zn and Zn-N bonds in CuZn@C NSs act as zincophilic sites to uniformly absorb Zn ions and prevent the formation of Zn dendrites, while also hindering the side reactions between the zinc anode and electrolyte. The CuZn@C NSs exhibited excellent zinc plating/exfoliation performance, long cycle life, and high capacity retention when used as anodes in CuZn@C/V2O5 full cells.