Composites of Gerbera delavayi Franch. flocs derived biocarbon and sheet-like nickel cobalt sulfide for advanced electrodes in supercapacitors
摘要
As highly efficient energy storage devices, performances of the supercapacitors are seriously influenced by electrochemical properties of the electrodes. This work is aimed at electrochemical properties improvement of the composites of biocarbon and nanocrystalline NiCo2S4 (NCS) via stimulating synergistic effect of the conductive skeleton and the active redox material for advanced electrodes in supercapacitors. Nitrogen-doped and activated biocarbon (NAGC) with hollow-tubular structure derived from flocs on the underside of Gerbera delavayi Franch. Leaves were anchored with sheet-like NiCo2S4 (NCS-S) nanocrystalline. Specific capacitances of 2282 F g−1 at 1 A g−1 was achieved by the NAGC@NCS-S electrode. Meanwhile, the capacitance retention is 98.96% over 5000 galvanostatic charge–discharge (GCD) cycles. An asymmetric supercapacitor (ASC) structured with NAGC@NCS-S//NAGC obtained high energy density of 58.1Wh kg−1 at power density of 935.1 W kg−1, and a capacitance retention of 96.5% over 5000 GCD cycles.