Ni(OH)2 cathode with oxygen vacancies induced from electroxidizing Ni3S2 nanosheets for aqueous rechargeable Ni–Zn battery

Aqueous rechargeable Ni–Zn batteries have attracted considerable focuses due to their low cost, environmental benefits, and resource abundance. Whereas, the inadequate exposed active sites and sluggish reaction kinetics are deemed as a major challenge pertaining to cathode materials. Herein, we propose a facile electroxidizing approach to produce β-Ni(OH)2 and subsequent induce abundant oxygen vacancies (Ov-Ni(OH)2) involving the sulfur leaching and oxide reorganization of Ni3S2 nanosheets. The introduced oxygen vacancies facilitate the electron transport and provide numerous exposed active sites in the energy storage application. The Ni3S2/Ov-Ni(OH)2 electrode delivers a specific capacitance of 1556.1 F g−1 at a current density of 0.5 A g−1. Moreover, the assembled aqueous rechargeable Ni3S2/Ov-Ni(OH)2//Zn battery presents a superior specific capacity of 222.4 mAh g−1 under 1.0 A g−1, remarkable cycling durability with 93.2% retention after 3000 cycles. Additionally, a remarkable energy density 384.6 Wh kg−1 coupling with a power density of 1.73 kW kg−1 can be acquired, outperforming most of the recently reported Zn-ion batteries. The investigation affords a new alternative for the development of high-performance cathode materials and aqueous rechargeable Ni–Zn batteries.