In situ growth of CuCo2S4 nanocrystals on N, S-codoped reduced graphene oxide nanosheets for supercapacitors

The design and synthesis of an electrode material with high specific capacitance and superior cycle stability for supercapacitors is extremely desirable. CuCo2S4 nanocrystals uniformly grown on the surface of N, and S codoped reduced graphene oxide (CuCo2S4/N, S–RGO) nanosheets were achieved via a one-step hydrothermal method. In this process, doping, sulfuration, and reduction were simultaneously achieved using thiosemicarbazide as raw material. When applied as an electrode material for supercapacitors, CuCo2S4/N, S–RGO hybrids offered higher specific capacity compared to CuCo2S4 nanocrystals. Furthermore, a CuCo2S4/N, S–RGO//N, S–RGO asymmetric supercapacitor (ASC) was assembled. The as-prepared ASC delivered the specific energy of 10.8 Wh kg–1 at 400 W kg–1 and good cycle performance (88.9% retention for 5000 cycles). In addition, an ASC device can drive a mini-fan. Therefore, CuCo2S4/N, S–RGO hybrids are potential electrode materials for supercapacitors.