(546e) Facile and Ultrafast Microwave Synthesis of NiCo2S4/Graphene Nanocomposite for High Performance Supercapacitor

Binary metal sulfides, especially nickel-cobalt sulfides (NiCo₂S₄), and their composites have attracted considerable attention as electrode materials for supercapacitors because of their excellent electronic conductivity and high capacitance compared to mono-metal sulfides and oxides. A two-step hydrothermal process is widely used to synthesize NiCo₂S₄. However, the traditional hydrothermal method has several drawbacks such as low energy efficiency, long reaction time and complex synthesis steps. Herein, we present an ultrafast microwave approach for fabricating NiCo₂S₄/graphene nanocomposite used for supercapacitor electrodes with excellent electrochemical performance. The morphologies, crystalline structures and elementary composition of the obtained nanocomposites were characterized by SEM, XRD, FTIR, and EDS. It is found that NiCo₂S₄ nanoparticles can uniformly grow on the surface of graphene after tens of seconds microwave irradiation. The presence of graphene not merely enhances the conductivity of nanocomposites but also provide the transport paths for ions in electrolytes and help to reduce energy loss, thus leading to enhanced electrochemical performance. Electrochemical results indicate that the specific capacitance of as-prepared NiCo₂S₄/graphene nanocomposite can reach up to 656 F g^-1 at 0.5 A g^-1. In addition, the NiCo₂S₄/graphene nanocomposite exhibits excellent cycling stability with capacitance retention over 80% even after 10000 cycles at 4 A g^-1. Thus, the current work provides an ultrafast and energy-efficient microwave method to synthesize high-performance NiCo₂S₄/graphene nanocomposite for supercapacitor applications.