Kelp-like structured NiCo2S4-C-MoS2 composite electrodes for high performance supercapacitor

Abstract

In this work, kelp-like structured NiCo2S4-C-MoS2 composite electrode materials for supercapacitors were successfully synthesized by a facile hydrothermal and solvothermal method. Due to the synergistic effect of the mixture of graphene-like MoS2 nanosheets, highly conductive carbon and NiCo2S4, the composite materials exhibited superior electrochemical performance: specific capacitance of 1601 F/g at a current density of 0.5 A/g, and rate performance of 61% at 10 A/g. Furthermore, an asymmetric supercapacitor (ASC), fabricated by using the NiCo2S4-C-MoS2 composite and activated carbon (AC) as positive and negative electrodes, respectively, showed a high energy density of 27.7 Wh/kg at a power density of 400 W/kg (it retained 14.4 Wh/kg at power density up to 8 kW/kg). After 1000 charge-discharge cycles at 2 A/g, the ASC device still maintained 60% of its initial capacitance. The outstanding performance of the NiCo2S4-C-MoS2 composite indicates its great potential for applications in high-performance energy storage systems.