Copper oxide-modified highly reversible Zn powder anode for aqueous Zn metal batteries

With the advantages of mature preparation technology, structural adjustability and suitability for large-scale application, Zn powder anode is considered to be an ideal electrode for realizing low-cost, high-energy–density aqueous Zn metal batteries. However, the high specific surface of Zn powders leads to severe side reactions such as hydrogen evolution and corrosion, thus limiting their widespread use. Here, this work develops a novel CuO@Zn powder anode with a synergy effect of surface wrapping and compositing. Zn powders are uniformly wrapped by small CuO particles due to the strong adsorption between Zn and CuO. The wrapped CuO particles build a good conductive framework to inhibit the structural collapse of the Zn powder caused by corrosion and non-uniform deposition. Meanwhile, CuO can also be used as a seed to guide the uniform deposition of Zn ions through its strong binding energy with Zn. As a result, the CuO@Zn anode can maintain a long cyclic life of 900 h at current density of 1 mA·cm⁻² and capacity of 1 mAh·cm⁻², as well as contribute to an excellent capacity retention of 92% after 800 cycles for CuO@Zn||NH₄V₄O₁₀ full cell. Even at high current density of 5 A·g⁻¹, the full cell exhibits a specific capacity of more than 200 mAh·g⁻¹ after 800 cycles, with a good capacity retention of 89%. This work provides a new idea for developing high-performance Zn powder-based anodes.

Graphical abstract