Electrodeposited Copper Tin Sulfide/Reduced Graphene Oxide Nanospikes for a High-Performance Supercapacitor Electrode

Abstract

Copper tin sulfide, Cu 4 SnS 4 (CTS), a ternary transition-metal chalcogenide with unique properties, including superior electrical conductivity, distinct crystal structure, and high theoretical capacity, is a potential candidate for supercapacitor (SC) electrode materials. However, there are few studies reporting the application of Cu 4 SnS 4 or its composites as electrode materials for SCs. The reported performance of the Cu 4 SnS 4 electrode is insufficient regarding cycle stability, rate capability, and specific capacity; probably resulting from poor electrical conductivity, restacking, and agglomeration of the active material during continued charge−discharge cycles. Such limitations can be overcome by incorporating graphene as a support material and employing a binder-free, facile, electrodeposition technique. This work reports the fabrication of a copper tin sulfide-reduced graphene oxide/nickel foam composite electrode (CTS−rGO/NF) through stepwise, facile electrodeposition of rGO and CTS on a NF substrate. Electrochemical evaluations confirmed the enhanced supercapacitive performance of the CTS−rGO/NF electrode compared to that of CTS/NF. A remarkably improved specific capacitance of 820.83 F g −1 was achieved for the CTS−rGO/NF composite electrode at a current density of 5 mA cm −2 , which is higher than that of CTS/NF (516.67 F g −1 ). The CTS−rGO/NF composite electrode also exhibited a high-rate capability of 73.1% for galvanostatic charge−discharge (GCD) current densities, ranging from 5 to 12 mA cm −2 , and improved cycling stability with over a 92% capacitance retention after 1000 continuous GCD cycles; demonstrating its excellent performance as an electrode material for energy storage applications, encompassing SCs. The enhanced performance of the CTS−rGO/NF electrode could be attributed to the synergetic effect of the enhanced conductivity and surface area introduced by the inclusion of rGO in the composite.