Boosting energy and power of Cu-doped NiCo2S4/graphite electrode for high performance supercapacitors

Cu-doped NiCo2S4/flake graphite nanosheet arrays were prepared by multi-step hydrothermal calcination. Three-dimensional structure provides a wealth of active sites and structure stability to improve the charging/discharging rate. Moreover, 5% Cu-doped NiCo2S4/flake graphite composite fulfills an excellent specific capacitance of 3080 F·g−1 at 1 A·g−1 and remains 2600 F·g−1 at 20 A·g−1 with an outstanding capacitance retention rate of 86% at 20 times current density. The all-solid supercapacitor with 5% Cu-doped NiCo2S4/flake graphite electrode and activated carbon electrode exhibits an excellent energy density of 79.4 Wh·g−1 at a power density of 400 W·kg−1 with an outstanding cycling stability of 94% retention after 10000 cycles,suggesting its great potential for the development of high-performance energy storage devices.