Mn3O4/activated carbon composites with enhanced electrochemical performances for electrochemical capacitors

The natural coconut shell activated carbon (AC) was firstly treated with KOH in advance, and the Mn3O4/AC composites in various AC rations were prepared by the hydrothermal process and subsequent heat treatment. The resulting Mn3O4/AC composites were characterized by means of different techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and so on. Morphological studies reveal the hierarchical porous structure of Mn3O4/AC composites. Mn3O4/AC nanocomposite with the activated carbon quality percentage of 10% exhibits the highest specific capacitance of 491.2 F g(-1) at the current density of 2 A g(-1) in 6 M KOH aqueous electrolyte measured from the charge-discharge process. The value is nearly 6 times higher than that of the pure Mn3O4 nanoparticles as an electrode for supercapacitor. The good performance of the as-prepared Mn3O4/AC composites as electrode materials may be attributed to the synergistic effects of the activated carbon and the Mn3O4. (C) 2017 Elsevier B.V. All rights reserved.