In-situ growth of KCu7S4@CoMoO4 core-shell structure on Ni foam for high performance supercapacitor electrode

Abstract

Supercapacitor, as a new energy storage device, holds the advantages of high-power density and fast charging/discharging rate. Then, ternary compounds have excellent electrochemical properties. In this paper, KCu7S4 @CoMoO4 with core-shell structure was prepared by two-step hydrothermal method. In this structure, CoMoO4 nanosheets in-situ grows on KCu7S4 microwires, which increases the active sites and provides plenty of ion transfer channels. The electrochemical performance and synergistic effect of KCu7S4 @CoMoO4 are investigated. The rational design of KCu7S4 @CoMoO4 core-shell structure is benefic to electrochemical performance, and the specific capacitance is as high as 2344 F/g at the current density of 0.5 A/g. An asymmetric supercapacitor presented the energy density of 84.31 Wh/kg at the power density of 254.12 W/kg. The device also displayed good cycle performance, and the capacity retention rate is 88.1% after 3500 cycles at 20 A/g. The results demonstrated that the KCu7S4 @CoMoO4 core-shell structure has great potential in supercapacitor.