Hydrothermal Synthesis of Nanostructured Manganese Oxide/Carbon Composites as Electrochemical Capacitors Electrodes

Nanoribbon-like manganese oxide (MnO(OH))/carbon composites were synthesized with a hydrothermal method at 150 degrees C for 6 h and 9 h. The MnO(OH) is in diameters of 4 similar to 8 nm and lengths up to several micrometers. The carbon particulates are of sphere-like morphological structures with diameters of 50 nm. With the reaction time increasing from 6 h to 9 h, the shapes of the carbon particulates turn to more regular. The cycle voltammetry and galvanostatic charge-discharge performances of the composites were analyzed with the composites as the working electrodes and nickel foam as the counter electrodes in 1.0 mol/L Na2SO4 electrolytes. The results show that a specific capacitance of 116.3 F/g can be obtained at a current density of 0.2 A/g and a retention of 82.6% is observed when current density increases to 2.0 A/g.