Supercapacitors Based on High Surface Area MoS2 and MoS2-Fe3O4 Nanostructures Supported on Physical Exfoliated Graphite

MoS2 nanosheets, mainly monolayer and nearly square, with very small lateral dimensions, a new nanostructure consisting of Fe3O4 nanoparticles covered by MoS2 nanosheets (MoS2/Fe3O4) and highly conductive physical exfoliated graphite (PHG) supporting well dispersed MoS2/Fe3O4 were prepared by a bottom up synthetic strategy able to give controlled morphology and structures. Raman Spectroscopy, Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TG-DTG) and X-ray diffraction (XRD) were employed for characterization. The electrochemical performances of MoS2, MoS2/Fe3O4 and MoS2/Fe3O4/PHG supercapacitors were investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests in 1 M H2SO4 solution. Very high specific capacitances of 387 F/g, 624 F/g and 830 F/g at a current density of 1 A/g, were obtained, respectively for the v nanosheets, MoS2/Fe3O4 and MoS2/Fe3O4/PHG. In particular, MoS2/Fe3O4/PHG thanks to its porous structure and the conductive network ensured by PHG support retains similar to 96% of its initial capacitance after 2200 cycles, indicating a good stability and a long cycle life.