Rapid and efficient synthesis of high-porous reduced graphene oxide/NiCo2S4 nanocomposites for supercapacitor application

Abstract A high-porous reduced graphene oxide/NiCo2S4 (RGO/NiCo2S4) nanocomposite was prepared by a rapid and efficient one-step microwave-assisted method. The prepared composite consisted of NiCo2S4 nanoneedles with diameters of several nanometers, which were well-anchored on the surface of RGO sheets. The prepared nanocomposite showed a high specific surface area, mesoporous structure and high conductivity, which was expected to yield a fast electron and ion movement, as well as a large electroactive area. The as-prepared electrode exhibited a high specific capacitance (1320 F g−1 at 1.5 A g−1), high rate capability (70.2% retention from 1 to 9 A g−1), and good cycling stability (≥96% retention after 2000 cycles). Besides, an asymmetric supercapacitor assembled using the RGO/NiCo2S4 as cathode active material and the RGO as anode active material exhibited a high capacitance of 146 F g−1 at 1 A g−1 and a high energy density of 46.7 Wh kg−1 at a power density of 1200.8 W kg−1 at an operating voltage of 0.8 V, suggesting its promising application as a high-performance electrical energy storage device.