Facile preparation of Mn3O4/rGO hybrid nanocomposite by sol–gel in situ reduction method with enhanced energy storage performance for supercapacitor applications

Pure Mn 3 O 4 and Mn 3 O 4 /rGO hybrid nanocomposites were synthesized by sol–gel based in situ reduction method. The structural properties of pure and nanocomposite materials were studied by XRD. The crystallite size of the Mn 3 O 4 nanoparticle was reduced in the nanocomposite as observed by XRD analysis. SEM and TEM images depict the spherical morphology of pristine Mn 3 O 4 nanoparticles and decoration of Mn 3 O 4 nanoparticle on rGO sheets. Raman spectra confirm the formation of Mn 3 O 4 /rGO nanohybrid composites as the A g mode of Mn 3 O 4 , D, and G bands of rGO were observed in the spectra. FTIR spectra confirm the presence of various functional groups of GO and the in situ reduction of GO into rGO. The electrochemical properties of the Mn 3 O 4 and Mn 3 O 4 /rGO composites were investigated by cyclic voltammetry analysis using 1 M KOH as an electrolyte. The cyclic voltammetry results show the pseudocapacitance behavior of Mn 3 O 4, whereas the hybrid nanocomposite exhibits the combined behaviors of pseudocapacitance and EDLC. The chronopotentiometry analysis demonstrated that the specific capacitance of Mn 3 O 4 /rGO nanocomposite (427 F g −1 ) was relatively higher than that of Mn 3 O 4 (136 F g −1 ) at 1 A/g. The impact of KOH electrolyte over the specific capacitance of a electrode material was comparatively analyzed with different electrolytes. The enhancement in the specific capacitance of the nanohybrid composite was attributed due to the strong electrode–electrolyte interaction of hybrid electrode material and synergetic effect of Mn 3 O 4 and rGO. Highlights Mn 3 O 4 /rGO nanocomposite was synthesized by sol–gel based in-situ reduction method. Crystallite size of the Mn 3 O 4 was reduced consistently while adding rGO 2 and 5%. TEM image confirms the spherical morphology of the Mn 3 O 4 nanoparticle (~10 nm) and Raman spectroscopy results confirm the formation of composites. Specific capacitance of the Mn 3 O 4 /rGO nanocomposite (427 F g −1 ) was higher than Mn 3 O 4 (136 F g −1 ). High specific capacitance of composite is due to the synergetic effect of Mn 3 O 4 /rGO.