Oxygen vacancies-rich cobalt-doped NiMoO4 nanosheets for high energy density and stable aqueous Ni-Zn battery

The enhancement of energy density and cycling stability is in urgent need for the widespread applications of aqueous rechargeable Ni-Zn batteries. Herein, a facile strategy has been employed to construct hierarchical Co-doped Ni-MoO4 nanosheets as the cathode for high-performance Ni-Zn battery. Benefiting from the merits of substantially improved electrical conductivity and increased concentration of oxygen vacancies, the NiMoO4 with 15% cobalt doping (denoted as CNMO-15) displays the best capacity of 361.4 mA h g−1 at a current density of 3 A g−1 and excellent cycle stability. Moreover, the assembled CNMO-15//Zn battery delivers a satisfactory specific capacity of 270.9 mA h g-1 at 2 A g−1 and a remarkable energy density of 474.1 W h kg−1 at 3.5 kW kg−1, together with a maximum power density of 10.3 kW kg−1 achieved at 118.8 W h kg−1. Noticeably, there is no capacity decay with a 119.8% retention observed after 5000 cycles, demonstrating its outstanding long lifespan. This work might provide valuable inspirations for the fabrication of high performance Ni Zn batteries with superior energy density and impressive stability.