Facile synthesis and electrochemical properties of α-MnO2 as electrode material for supercapacitors

MnO2 as the electrode material for supercapacitors has attracted much interest in recent years. However, there are still some restrictions for its application. In this paper, to improve the capacitive properties of MnO2, material was synthesized by a facile and efficient low-temperature reduction reaction between KMnO4 and Cu foil in sulfuric acid solutions. The results showed that the initial concentrations of KMnO4 and the addition of concentrated sulfuric acid have distinct influence on the structure, morphology and electrochemical properties of the as-prepared MnO2. Particularly, morphological characterization displayed that the sample synthesized in 0.05molL(-1) KMnO4 and 16mL concentrated sulfuric acid is composed of urchins with the average diameter of 0.7 mu m. The product exhibits a discharge specific capacitance of 288.03Fg(-1) at the constant current density of 65mAg(-1). The capacitance remains about 50% of the initial capacitance at 250mAg(-1), and is 100.06Fg(-1) after the 100th cycle. (c) 2013 Curtin University of Technology and John Wiley & Sons, Ltd.