Manganese oxide precipitated into activated carbon electrodes for electrochemical capacitors
- 199 Downloads
Manganese oxide was prepared at different pH and temperatures and then precipitated into activated carbon by the chemical impregnation method. Size distributions of manganese oxide sol were also measured by light scattering. The electrodes were annealed in nitrogen gas at different temperatures. In addition, electrochemical characterization was carried out using cyclic voltammetry (CV) at a scan rate of 25 mV s−1 and chronopotentiometry (CP) with constant-current (10 mA cm−2). Maximum capacitance of 461.3 F g−1 was obtained in a 0.1 M Na2SO4 solution for manganese oxide prepared under optimum conditions (pH = 13.11 and T = 25 ºC) and annealed at a temperature of 195 ºC. The manganese oxide particle size decreased with annealing. This probably leads to increased specific capacitance. Using X-ray photoelectron spectroscopy (XPS) the results reveal that manganese oxide species are transformed from hydroxide to oxide after annealing.
KeywordsManganese oxide Chemical impregnation Annealing Scanning electron microscope Electrochemical capacitors
- 1.Conway BE (1999) Electrochemical supercapacitors – scientific fundamentals and technological applications. Kluwer Academic/Plenum Publishers, New YorkGoogle Scholar
- 20.Dean JA, Lange NA (1973) Lange’s handbook of chemistry, 8.164. McGraw-Hill, New YorkGoogle Scholar