Nanoflower-like Cu2CoSnS4 grown on nickel foam as binder-free electrode material for asymmetric supercapacitors with high rate and capacitance

The self-supporting binder-free electrode material with a special porous structure and abundant electrochemical active sites is viewed as the ideal electrode material for supercapacitors. In this work, nanoflower-like Cu2CoSnS4 was first constructed on nickel foam (NF) substrate (CCTS/NF) by a one-step solvothermal method. The nanoflower-like shape increases the channels for ion transport and presents a massive quantity of active sites, which is crucial to improving electrochemical performance. What’s more, the significant synergistic effect between the ternary transition metal ions enhances the electrochemical performance as well. As a result, the CCTS/NF-3 performs a standout specific capacitance of 1690 mF cm-2 at 2 mA cm-2, a perfect rate performance of 79.6% and a superb cycle consistency of 99.6% after 5000 cycles. The assembled asymmetric supercapacitor (ASC) performs a high potential window of 0–1.4 V, a superb energy density of 0.0065 mWh cm-2 at 0.14 mW cm-2 and magnificent capacitance remains (95.6% after 5000 cycles). The electrode material has low acquisition cost and terrific electrochemical performance, and has broad utility possibilities in the supercapacitor market. •Nanoflower-like Cu2CoSnS4 was constructed on nickel foam by a facile one-step solvothermal method.•The material exhibited a high specific surface area and porous structure.•Significant synergistic effect between multi-metal ions enhanced the electrochemical performance.•The CCTS/NF-3 performed an excellent capacitance retention of 99.6% after 5000 cycles.