Fast Track Article

Fabrication of graphene/polypyrrole nanotube/MnO₂ nanotube composite and its supercapacitor application

¹ School of Materials Science and Engineering, Beihang University, Beijing 100191, P.R. China
² Jiangsu Electric Power Maintenance Branch Company, State Grid Corporation of China (SGCC), Nanjing 211102, Jiangsu, P.R. China

^a e-mail: liujh@buaa.edu.cn

Received: 25 April 2012
Revised: 2 June 2012
Accepted: 5 June 2012
Published online: 5 July 2012

Abstract

A novel composite is fabricated through hybridizing graphene with polypyrrole (PPY) nanotube and manganese dioxide (MnO₂) nanotube to comprehensively utilize the electrical double layer capacitance and pseudo-capacitance. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy are employed to characterize its structure. The SEM and TEM images illustrate that graphene/PPY nanotube/MnO₂ nanotube composite (GPM) presents interconnected structure. The result of Raman analysis demonstrates the intimate interactions among PPY, graphene and MnO₂. In addition, cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques are used to measure the electrochemical properties. It is revealed that GPM presents excellent high-rate performance and its capacitance is as high as 469.5 Fg⁻¹ at a current density of 0.3 Ag⁻¹, higher than that of PPY and chemically reduced graphene sheet as well as the materials reported in the literature. Furthermore, long-term charge-discharge cycle test confirms that the fabrication of GPM can effectively merge the merits of graphene, PPY and MnO₂. Additionally, EIS analysis illustrates that the presence of conductive graphene as well as the intimate interactions among graphene, PPY and MnO₂ lead to the good electrochemical stability.