Constructing aqueous Zn//Ni hybrid battery with NiSe nanorod array on nickel foam and redox electrolytes for high-performance electrochemical energy storage

Aqueous rechargeable zinc-nickel (Zn//Ni) batteries have attracted a lot of attention because of their advantages such as high operating voltage, low cost and safety. However, the relatively low energy density, power density and stability delay its practical application. Here, NiSe single crystal nanorod array was prepared in situ on nickel foam with a simple hydrothermal method. The NiSe-12 h sample showed a higher areal specific capacity due to its high conductivity and a consistent hexagonal phase NiSe nanorod array structure to effectively expose the active substance and accelerate the reaction kinetics process. The NiSe//Zn-KFC hybrid battery was constructed based on the solid Faraday redox reaction of the NiSe-12 h electrode itself and its electrocatalysis on potassium ferricyanide. Compared with the conventional NiSe//Zn-U battery, the NiSe//Zn-KFC hybrid battery showed higher energy density (2.26 mWh/cm2 vs. 1.22 mWh/cm2), peak power density (95.93 mW/cm2 vs. 76.01 mW/cm2), cycle stability (capacity retention rate 80.89% vs. 64.75% after 1300 cycles) and rate performance under the same test conditions. The construction of this aqueous Zn-Ni hybrid concept battery opened a bright window for the development of high-performance aqueous rechargeable zinc-nickel battery.