Facile Synthesis of Mn₃O₄ Nanoparticles Decorated Graphene as Enhanced Performance Electrode for Supercapacitor

Graphene was prepared by using the plant stem as a biotemplate through high temperature carbonization and Mn₃O₄/graphene composites were then prepared via a simple hydrothermal process. The surface morphology and structure of the Mn₃O₄/graphene hybrids were characterized by X-ray diffraction spectroscopy (XRD), Raman spectra, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectrogram (XPS), N₂ adsorption–desorption isotherms and electrochemical test. The results showed that the metal oxide nanoparticles were uniformly supported on the surface of graphene. Judging from the XRD, XPS and Raman, we could acquire that the Mn₃O₄ nanoparticle was in the crystal form while the average crystallite size was about 21 nm. The composites exhibited excellent specific capacitance as high as 196 F/g and the capacitance of the composites was 88% retained after 1000 cycles in 1 M Na₂SO₄ electrolyte at a charging rate of 2 A/g. The superior electrochemical properties could be due to the improved accessible area for ions in electrolytes and enhanced conductivities. The present study provides a facile way to design a high-performance Mn₃O₄/graphene based supercapacitor electrode and the concept is extendable to other pseudo capacitive electrodes.