A nano-copper particle-modified zinc anode as a protective coating enables dendrite-free aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have become one of the hotspots in large-scale energy storage due to their advantages of high safety, low cost, and environmental friendliness. However, the metallic Zn anode is prone to dendritic growth and electrochemical corrosion on the surface during cycling, posing a serious challenge to the cycling life of AZIBs. Herein, a simple, low-cost and suitable for mass production method is reported to construct an anti-corrosive nano-copper particle protective coating on the surface of a metallic zinc (Cu-Zn) anode. The prepared nano-copper particles are evenly distributed on the surface of Zn, providing a uniform electric field distribution and successfully suppressing electrochemical corrosion on the surface. Importantly, it is confirmed microscopically that the Cu-Zn anode maintains homogeneous stripping and plating processes, effectively alleviating dendrite formation. Additionally, the resulting Cu-Zn anode exhibits a lower overpotential, which offers a lower interfacial transfer resistance of the battery. The symmetric battery test results show that the unmodified bare Zn anode fails after 58 h at 1 mA cm^-2 and 0.5 mA h cm^-2, while the Cu-Zn anode can remain stable for more than 3200 h. Furthermore, the assembled Cu-Zn||α-MnO₂ battery delivers a capacity of 173.2 mA h g^-1 after 2500 cycles at a high current density of 2000 mA g^-1, and the capacity retention rate is 90.6%. The results indicate the great potential application of the nano-copper particle-modified zinc anode, which has provided an appealing strategy for improving the stability of AZIBs to promote the industrial development of the energy storage field.