One-step combustion synthesis of C-Mn3O4/MnO composites with high electrochemical performance for supercapacitor

Carbon inlaid composites (C-Mn3O4/MnO) were prepared via igniting manganese acetate anhydrous ethanol solution in a beaker, and the resulting nanocomposites present homogeneous dispersion and stable property. The successful fabrication of the as-prepared samples was demonstrated by x-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Various electrochemical measurements including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) were carried out. The maximum specific capacitance value of the C-Mn3O4/MnO composites can reach up to 204 F g−1 at a current density of 1 A g−1, which is much higher than that of Mn3O4/MnO composites (90 F g−1). The incorporated carbon improves the electrochemical performance and effectively decreases the charge transfer resistance of the composites (0.67 Ω) compared with pure Mn3O4/MnO composites (42.4 Ω). Surprisingly, as the number of cycles increase, the specific capacitance of C-Mn3O4/MnO composites become larger with a 188.3% of the initial specific capacitance value. This study develops a novel and facile method to fabricate composites of carbon and manganic oxide which have potential application in supercapacitor.