Nano-Sized MnO_2-Carbon Composite for Conductive Agent-Free Supercapacitor Electrodes

摘要

The manganese oxide-carbon composite (MnO_2-C) containing Manganese oxide nanorods and carbon nanosphere is successfully synthesized based on the direct redox reaction between KMnO_4 and carbon nanosphere. The morphology of the resulting composite has been investigated by scanning electron microscopy and transmission electron microscopy. The structure of the as-synthesized sample has been characterized using X-ray diffraction and so on. Electrochemical experimental results, including cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge, have showed that the initial capacitance of MnO_2-C composite is 150 F g~(-1) at a current density of 0.6 A g~(-1), and a superior coulombic efficiency remains close to 100% with the capacitance above 120 F g~(-1) during the continuous 1000 cycles of galvanostatic charge-discharge. These results have revealed that the MnO_2-C composite displays a prominent capacitive performance, which are important in practical applications for supercapacitor.