The effects of morphology re-arrangements on the pseudocapacitive properties of mesoporous molybdenum disulfide (MoS2) nanoflakes

Abstract

Mesoporous molybdenum disulfide (MoS(sub2)) with different morphologies have been prepared via hydrothermal method using different solvents, water or water/acetone mixture. The MoS(sub2) obtained with water alone gave a graphene-like nanoflakes (g-MoS(sub2)) while the other with water/acetone (1:1 ratio) gave a hollow-like morphology (h-MoS(sub2)). Both materials are modified with carbon nanospheres as conductive material and investigated as symmetric pseudocapacitors in aqueous electrolyte (1 M Na(sub2)SO(sub4) solution). The physico-chemical properties of the MoS(sub2) layered materials have been interrogated using the surface area analysis (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, fourier-transform infrared (FTIR) spectroscopy, and advanced electrochemistry including cyclic voltammetry (CV), galvanostatic cycling with potential limitation (GCPL), repetitive electrochemical cycling tests, and electrochemical impedance spectroscopy (EIS). Interestingly, a simple change of synthesis solvents confers on the MoS(sub2) materials different morphologies, surface areas, and structural parameters, correlated by electrochemical capacitive properties. The g-MoS(sub2) exhibits higher surface area, higher capacitance parameters (specific capacitance of 183 F g(sup-1), maximum energy density of 9.2 Wh kg(sup-1) and power density of 2.9 kW kg(sup-1)) but less stable electrochemical cycling compared to the h-MoS(sub2). The findings show promises for the ability to tune the morphology of MoS(sub2) materials for enhanced energy storage.