Flower-like and porous Ni3S2 nanosheets for high performance supercapacitors

Transition metal sulfides have received significant attention as electrode materials for their low cost and high specific capacitance. Herein, flower-like and porous Ni₃S₂-120-10 assembled by nanosheets is directly grown on nickel foams through a facile one-step hydrothermal method. Benefited from the porous structure, the flower-like compound offers respectable gravimetric specific capacitance of 1899.4F g⁻¹ at a current density of 1 A/g in 6 M KOH aqueous electrolyte. Moreover, an asymmetric supercapacitor (ASC) was obtained using Ni₃S₂-120-10 as the positive electrode and active carbon as the negative electrode with 6 M KOH as the electrolyte. Ni₃S₂-120-10//AC displays a high power density of 1590.7 W kg⁻¹ at the energy density of 17.6 Wh kg⁻¹ accompanied with an outstanding cyclic stability (83.2 % of initial capacitance after 8000 cycles). This work provides a facile strategy for the next generation energy-storage applications with high stability and superior electrochemical capacity.