A novel Co9S8–MoS2 nanosheet arrays@HCSs with superior capacitive and cycling performance for hybrid supercapacitor

Abstract

Due to high conductivity and electrochemical activity, transition metal sulfides and their complexes have emerged as attractive electrode materials for supercapacitors. Herein, heterostructures of Co9S8–MoS2 nanosheet arrays on the hollow carbon spheres (HCSs) with yolk-shell structure (Co9S8–MoS2 NSAs@HCSs) are synthesized by a hydrothermal method and in-situ sulfurization of silicates. This core-shell structure can effectively improve the conductivity and reaction kinetics, resulting in a notable improvement in the cycling and capacity properties. The Co9S8–MoS2 NSA@HCSs electrode has an outstanding cycle stability (96.9 %) after 10, 000 cycles at 10 A g−1 and a high specific capacity of 804C g−1 at 1 A g−1. The effects of solution concentration and sulfurization time on the microstructures and electrochemical properties of the electrode are also investigated. Furthermore, the hybrid supercapacitor (HSC) is assembled with Co9S8–MoS2 NSA@HCSs (positive electrode) and HCSs (negative electrode). Additionally, the HSC delivers 98.2 % of cycling stability after 10, 000 cycles at 10 A g−1. The energy density of 45.6 Wh kg−1 can be obtained at the power density of 770.4 W kg−1.