Hydrothermally Grown SnO2 and SnO2/rGO Nanocomposite and Its Physio-Electrochemical Studies for Pseudocapacitor Electrode Applications

In this present work, the transition metal oxides of SnO2 and SnO2/rGO nanocomposite were synthesized through a facile hydrothermal method for supercapacitor electrode material applications. The structural, morphological, and elemental analysis of the synthesised samples were characterised by X-ray diffractometer technique (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray analysis (EDX), and High-resolution transmission electron microscopy (HR-TEM). The morphology of SnO2 was an agglomeration of quasi-spherical-shaped particles with a diameter range of 12-19 nm, as observed using the HR-TEM technique. The optical properties were characterised by UV-vis and Raman spectroscopy. The electrochemical performance of SnO2 and SnO2/rGO nanocomposite electrode was studied in a 3 M KOH electrolyte. A specific capacitance of 346 F g(-1) at a current density of 0.95 A g(-1) for the SnO2/rGO nanocomposite electrode was recorded, which was significantly higher than that of the as-synthesised SnO2 electrode (267 F g(-1)). The higher capacitance obtained was due to the synergistic effect of excellent conductivity and a high surface area of rGO within the composite electrode. The exceptional electrochemical properties clearly indicate that the SnO2/rGO nanocomposites are the best for highly efficient pseudocapacitor electrodes in future energy storage device applications.