Improving supercapacitive performance of CNTs/NiCo2S4 composites by interface regulation.

• The CNTs/NiCo 2 S 4 hybrids with three kinds of interfaces were designed and prepared. • Supercapacitive properties of CNTs/NiCo 2 S 4 were improved by interface regulation. • An aqueous asymmetric supercapacitor was successfully assembled and evaluated. • An CNT:Ni@NiCo 2 S 4 //AC device showed excellent electrochemical energy storage. Integrating metal sulfides with carbon materials is considered as one of effective approaches to meet the demand of high-performance electrochemical energy storage materials. In this paper, we emphasize the critical role of interface between NiCo 2 S 4 and CNTs for supercapacitive performance of the hybrid structures. The CNTs/NiCo 2 S 4 nanocomposites with three kinds of interfaces are prepared using a one-step hydrothermal method by adding the pristine CNTs, surface-oxidized CNTs and nickel-coated CNTs, respectively. Benefiting from the unique nickel interface structure that adequately realizes the effective utilization of the conductive CNTs owing to the homogeneous dispersion of CNTs throughout the matrix as well as the strong interface adhesion by a bridging role, the CNTs:Ni@NiCo 2 S 4 nanocomposite exhibits a high specific capacity of 224.0 mAh g−1 at a current density of 1 A g−1. An asymmetric supercapacitor assembled by the CNTs:Ni@NiCo 2 S 4 nanocomposite and activated carbon as positive electrode and negative electrode, respectively, exhibits a high energy density of 60.7 Wh kg−1 at a power density of 800 W kg−1 and an excellent cycling stability of 88% capacitance retention after 10,000 cycles at 10 A g−1. This work described herein provides a new strategy for development of high-performance energy storage materials. [ABSTRACT FROM AUTHOR]