In-situ growth of CaC2O4 on ZnO microspheres for zinc nickel secondary batteries with high rate performance and long cycle stability

[Display omitted] •ZnO@CaC2O4 prepared by water bath method is firstly introduced into Zn-Ni batteries.•ZnO@CaC2O4 solves the problems of zinc dendrite and hydrogen precipitation reactions.•The ZnO@CaC2O4 achieves ultra-long cycle stability of 2100 cycles.•The average discharge-specific capacity of this work can attain 570.7 mAh·g−1. Alkaline zinc-nickel batteries have attracted the attention of many researchers because of their low cost, environmental friendliness, and safety. However, the notorious zinc dendrite and hydrogen evolution issues have seriously hindered the commercialization progress. Herein, ZnO@CaC2O4 microspheres are constructed with a two-step water bath method. It has a dual inhibition of dendrite growth due to the significant interaction of carbonyl oxygen and the regulation of zincate concentration by calcium ions, favoring ion transport and inducing zinc deposition efficiently. Besides, the hydrogen bond formed by carbonyl oxygen and water molecule can inhibit water activity at the reaction interface, thus suppressing side reactions such as hydrogen evolution. Consequently, the ZnO@CaC2O4 anode achieves a high specific capacity (Average value 570.7 mAh·g−1), high rate performance (10C), and long cycle stability (2100 cycles). This method of dendrite suppression and hydrogen evolution control provides a new approach to designing high-performance zinc-nickel electrode materials.