Engineering Sulfur Vacancies of Ni<sub>3</sub>S<sub>2</sub> Nanosheets as a Binder-Free Cathode for an Aqueous Rechargeable Ni-Zn Battery
Yapeng He, Panpan Zhang, Hui Huang, Xiaobo Li, Xinhua Zhai, Buming Chen, Zhongcheng Guo
Abstract
The development of an efficient metal sulfide cathode is of great importance and an ongoing challenge for the practical application of an aqueous rechargeable Ni-Zn battery. Herein, Ni3S2 nanosheets with abundant sulfur vacancies (r-Ni3S2) have been successfully prepared via hydrothermal reaction and surface engineering, which are further employed as the binder-free cathode of the aqueous Ni-Zn battery. Benefitting from the features of substantially improved electrical conductivity, low band gap, abundant active sites, and good intrinsic capacity, the r-Ni3S2 electrode delivers an impressive reversible specific capacitance (1621.6 F g–1 at 0.2 A g–1) and extraordinary rate capability (62.1% retention under 8 A g–1). Moreover, the aqueous rechargeable r-Ni3S2//Zn battery exhibits a remarkable specific capacity (240.8 mAh g–1 at 1 A g–1) and preeminent cycling durability (only 8.4% decay after 3000 cycles). Besides, a glorious energy density of 419.6 Wh kg–1 together with a peak power density of 1.84 kW kg–1 could be achieved, surpassing a significant percentage of the reported Ni-Zn batteries. The results reveal that the r-Ni3S2 cathode with abundant sulfur vacancies and the adopted facile approach possesses huge promotion potential for Ni-Zn batteries and is promising to numerous electronics and electric vehicle applications in the future.