High dispersion of γ-MnO2 on well-aligned carbon nanotube arrays and its application in supercapacitors

The well-aligned carbon nanotube arrays (ACNTs) were used as supporting material and the γ-MnO2/ACNT electrode with high dispersion of γ-MnO2 has been prepared by electrochemically induced deposition method. The crystal structure and morphology of the γ-MnO2/ACNT electrode were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The capacitive properties of γ-MnO2/ACNT electrode were characterized by cyclic voltammetry and galvanostatic charge–discharge method. The specific capacitance of the γ-MnO2/ACNT electrode is as high as 784 F g− 1 based on γ-MnO2 and 234 F g− 1 based on γ-MnO2/ACNT composites in 0.1 M Na2SO4 aqueous solution from 0 to 1 V when the charge–discharge current density is 1 mA cm− 2. Additionally, the electrode shows excellent power characteristics, high electrochemical reversibility and excellent long-term charge–discharge cycle stability.