Hydrothermal Synthesis of CuCo S Nano-structure and N-Doped Graphene for High- 2 4 Performance Aqueous Asymmetric Supercapacitors

Recently, transition metal sulfides have drawn a lot of attention due to their potential application in energy and environmental fields. In this paper, we present a simple and facile method for preparing CuCo S nanoparticles as high performance supercapacitor electrode materials. 2 4 -1 -1 Electrochemical measurements exhibit that the CuCo S nanoparticles electrode has a high specific capacitance of (190 C g at 1A g ), 2 4 -1 relatively high rate capability (46 % capacitance retention at 10A g ) and good cycling stability (77 % of the initial specific capacitance can be -1 maintained after 3000 cycles at 4A g ). When fabricated as aqueous asymmetric supercapacitor by using CuCo S nanoparticles and N-doped 2 4 graphene (NG) composites as the positive electrode and the negative electrode, respectively. The assembled device exhibits a high energy -1 -1 -1 density of 32.7 Wh kg at a power density of 794 W kg . And it still operates at a high power density of 6.4 kW kg with an energy density -1 -1 of 19.5 Wh kg . Moreover, after 6000 consecutive GCD cycles at a current density of 4 A g , 78.0 % of the initial capacitance value can be maintained. These attractive results manifest that CuCo S //NG hold a great potential for practical applications in the field of energy storage 2 4