Synthesis of hierarchical bimetallic sulfide NiCo2S4 for high-performance supercapacitors

Currently, the research of bimetallic sulfide as electrode materials for supercapacitors has been intensely concerned. Herein, a feasible hydrothermal method has been proposed to fabricate NiCo2S4 nanorod arrays on Ni foam (NiCo2S4/NF). The distinct structure of the material with nanorods as trunk and nanowires as branches can be achieved by precisely controlling the sulfidation time. By virtue of the rough surface and such hierarchical structure, the as-prepared NiCo2S4/NF electrode exhibits excellent electrochemical performance with specific capacitance of 3093 F g-1 (343.7 mA h g-1) at the current density of 5 A g-1 and 2130 F g-1 (236.7 mA h g-1) at the current density of 30 A g-1. When NiCo2S4/NF is used as the positive electrode, the assembled asymmetric supercapacitor device shows a high energy density of 39.3 Wh kg-1 at a power density of 800 W kg-1, and an energy density of 32.5 Wh kg-1 can be maintained at a power density as high as 3199.8 W kg-1.