Assembly of polypyrrole nanotube@MnO2 composites with an improved electrochemical capacitance

A facile strategy is presented to fabricate polypyrrole nanotube@manganese dioxide (PPy@MnO2) composites. The effect of KMnO4 concentration on the morphology and property of PPy@MnO2 composites is investigated. The microstrucutres and properties of the resulting PPy@MnO2 composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray diffraction (EDX), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and electrochemical measurements. The results indicate that the PPy@MnO2 composites possess high specific capacitance and good cyclic stability due to the coating of MnO2 onto PPy nanotubes. The specific capacitance of 403 F/g for the PPy@MnO2 composite is obtained from galvanostatic charge-discharge experiment at a current density of 1 A/g, exhibiting the potential application for supercapacitors. (C) 2015 Elsevier B.V. All rights reserved.