Synthesis, characterization and electrochemical performance of activated carbon supported MnO2 for electrochemical capacitor

Abstract

MnO2 was synthesized by adding activated carbon into KMnO4 solution and stirred in a magnetic or ultrasonic stirrer. The obtained MnAC samples were characterized by means of XRD, TGA, TPR-H2, SEM and BET. All samples are amorphous and have porous structure. Mn.AC-M prepared by magnetic stirring have higher manganese content, earlier reduction temperature, smoother surface area while Mn.AC-U prepared by ultrasonic stirring have larger specific surface area and pore volume. Electrochemical studies revealed that at low scan rate the specific capacitance of MnAC-U is larger than that of MnAC-M, while at high scan rate the specific capacitance of MnAC-M is higher. All the results indicated that the differences of the performances of MnAC electrodes from the different stirring methods arose from the different micro structure characteristic and the metal oxide loading of MnAC samples.