Facile synthesis of MnO2/CNT nanocomposite and its electrochemical performance for supercapacitors

A nanocomposite of manganese dioxide coated on the carbon nanotubes (MnO2/CNTs) was synthesized by a facile direct redox reaction between potassium permanganate and carbon nanotubes without any other oxidant or reductant addition. The morphology, microstructure and crystalline form of this MnO2/CNT nanocomposite were characterized by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties are characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD). The results show that the facile prepared MnO2/CNTs nanocomposite shows specific capacitance of 162.2 F g−1 at the current density of 0.2 A g−1 and excellent charge/discharge property with 90% of its specific capacitance kept after 2000 cycles at the current density of 5 A g−1.

► MnO2/CNTs are prepared by direct redox reaction between KMnO4 and carbon nanotubes. ► This preparation method is a simple and green without any other additives. ► MnO2/CNTs show specific capacitance of 162.2 F g−1 at the current density of 0.2 A g−1. ► MnO2/CNTs exhibit excellent charge–discharge property.