Alkaline Copper Phosphate Coating Exhibiting Zincophilic and Hydrophobic Characteristics Achieves High-Performance in Aqueous Zinc-Ion Batteries

Abstract

Severe dendrite growth and the process of side reactions have severely affected the application of aqueous zinc-ion batteries (AZIBs) composed of metal zinc anodes in large-scale fields. In this study, basic copper phosphate was synthesized by the hydrothermal method and coated on zinc foil (CUPH-Zn) to solve the above problems. Utilizing the affinity of basic copper phosphate toward zinc, the nucleation resistance was decreased, and the zinc plating/stripping behavior on the surface of the zinc anode was regulated. At the same time, the granular porous morphology formed by freeze-drying is transformed into a nanoflower-shaped porous morphology during the cycling process, which increases the active sites and provides favorable channels for zinc ion deposition. This nanoflower-shaped porous morphology cooperates with the highly hydrophobic basic copper phosphate, inhibits the hydrogen evolution reaction and corrosion reaction, and thereby reduces the formation of byproducts. Owing to these advantages, the CUPH-Zn battery demonstrates outstanding cycle life in both symmetric batteries (Cycle time:700 h, 0.8 mA cm^–2 and 13.7% depth of discharge) and full batteries (cycle 3500 times, 2 A g^–1 and 3.1 Negative/Positive). Consequently, this study offers innovative insights into constructing a zincophilic and hydrophobic interface layer for highly utilized zinc foil.