Surface-amorphized nickel sulfide with boosted electrochemical performance for aqueous energy storage

The ingenious structural design of electrode materials has a great influence on boosting the integrated conductivity and improving the electrochemical behavior of energy storage equipment. In this work, a surface-amorphized sandwich-type Ni₃S₂ nanosheet is synthesized by an easy hydrothermal and solution treatment technique. Because of the in-built defect-rich feature of the amorphous Ni₃S₂ layer, the constructed crystalline/amorphous heterointerface as well as dual nanopore structure of Ni₃S₂ nanosheet, the electron/ion transport and interfacial charge transfer is boosted, which contribute to high ionic conductivity and low resistance of the SA-Ni₃S₂ electrode. The SA-Ni₃S₂ electrode shows high specific capacitance (1767.6 F g⁻¹ at 0.5 A g⁻¹); the SA-Ni₃S₂//AC device delivers high specific capacitance (131.2 F g⁻¹ at 0.2 A g⁻¹) and outstanding cycle stability (75% capacitance retention after 10000 cycles). In Ni-Zn battery measurement, the SA-Ni₃S₂//Zn exhibits satisfying specific capacity (211.2 mAh g⁻¹ at 0.5 A g⁻¹) and cycle durability (68% capacity decay after 2000 cycles). The results imply that the rational design of surface-amorphized heterostructure is helpful for fabrication of electrode materials with high electrochemical performance in energy storage applications.