Role of precursor concentration in tuning the electrochemical performance of MoS₂ nanoflowers

A method to tune the electrochemical energy storage properties of molybdenum disulfide (MoS2) nanoflowers has been explored. The MoS2 nanoflowers were synthesized by solution based hydrothermal route using ammonium heptamolybdate tetrahydrate (AHM) and thiourea (TU) at 220 celcius. X-ray diffraction and Raman spectroscopy indicated the formation of 2H-phase of MoS2 nanoflowers. Electron microscopy analysis reveals that the petal density, petal thickness and linear porosity of MoS2 nanoflowers vary with the precursor weight ratio of AHM and TU. Enhanced specific capacitance value of -160 F/g at 2 A/g was obtained by suitably tailoring the precursor ratio. The electrochemical properties of MoS2 nanoflowers were improved by tuning the electrolyte concentration to 1 M Na2SO4. Further, the effect of different electrolytes on the applied potential window was studied; NaClO4 electrolyte provides a large potential window (-2.2 eV) as compared to Na2SO4, which can be a suitable electrolyte for high energy density solid-state supercapacitor applications.