Layer-by-layer self-assembly of ternary MoS2-rGO@PPyNTs nanocomposites for high performance supercapacitor electrode

Abstract

In order to prevent the agglomeration and effective utilization of surface area of reduced graphene oxide (rGO) nanosheets for supercapacitor electrode, layered molybdenum disulfide/ reduced graphene oxide (MoS2/rGO) nanocomposite has been synthesized by layer-by-layer self-assembly of positively charged MoS2 nanosheets with negatively charged graphene oxide (GO) nanosheet followed by vacuum-drying and hydrothermal reduction of GO. Ternary MoS2-rGO@PPyNTs nanocomposites were obtained by combining pre-synthesized Polypyrrole nanotubes (PPyNTs) with layered MoS2-GO followed by in-situ hydrothermal reduction of GO. The porous layered structure of MOS2-rGO nanocomposite provides enormous surface area, enhanced electronic conductivity and additional electro-active sites. MoS2-PPyNTs, rGO-PPyNTs and PPyNTs electrodes were also prepared and compared their electrochemical performance with the ternary electrode. The synergetic effect of layer-by-layer assembly of MoS2 and rGO nanosheets with PPyNTs imparts immense electrochemical activity with an extraordinary specific capacitance of 1561.25 F g−1 at 1 A g−1. The ternary nanocomposite possess energy density and power density of 555 W h kg-1 and 800 W kg-1, respectively at 1-fold current density in the potential range −0.3 to 1.3 V. MoS2-rGO@PPyNTs/ITO ternary electrode also possesses cycling stability of 72% of initial specific capacitance after 10,000 cycles at 10-fold current density.