N-doped carbon quantum dots boost the electrochemical supercapacitive performance and cyclic stability of MoS2

We report on the successful synthesis of flower-like MoS2/N-doped carbon dots (CDs) composite nanospheres via a facile solvothermal method making use of the layered structure of MoS2 and the excellent conductivity of CDs. The structural, compositional, and morphological properties of the fabricated electrodes were investigated using XRD, XPS, EDS, Raman spectroscopy, FTIR, TEM, and FE-SEM techniques. The addition of carbon dots to MoS2 improved the cyclic stability, wettability, and conductivity of the fabricated composites upon their use as supercapacitor electrodes. The supercapacitor electrodes showed a specific capacitance as high as 250.55 Fg(-1) at a scan rate of 10 mV/s and 149.21 Fg(-1) at 0.5 A/g. A symmetric supercapacitor device composed of MoS2/NCDs composite and activated carbon as the positive and negative electrodes, respectively delivered an energy density and a power density of 20.01 Wh/kg and 350 W/kg, respectively with 98% Coulombic efficiency after 5000 cycles, indicating the high performance of the fabricated electrodes.