Hydrothermal Synthesis of CuCo2S4 Nano-structure and N-Doped Graphene for High-Performance Aqueous Asymmetric Supercapacitors
Abstract
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 CuCo2S4 nanoparticles as high performance supercapacitor electrode materials. Electrochemical measurements exhibit that the CuCo2S4 nanoparticles electrode has a high specific capacitance of (190 C g-1 at 1A g-1), relatively high rate capability (46 % capacitance retention at 10A g-1) and good cycling stability (77 % of the initial specific capacitance can be maintained after 3000 cycles at 4A g-1). When fabricated as aqueous asymmetric supercapacitor by using CuCo2S4 nanoparticles and N-doped graphene (NG) composites as the positive electrode and the negative electrode, respectively. The assembled device exhibits a high energy density of 32.7 Wh kg-1 at a power density of 794 W kg-1. And it still operates at a high power density of 6.4 kW kg-1 with an energy density of 19.5 Wh kg-1. Moreover, after 6000 consecutive GCD cycles at a current density of 4 A g-1, 78.0 % of the initial capacitance value can be maintained. These attractive results manifest that CuCo2S4 //NG hold a great potential for practical applications in the field of energy storage system.
