Effect of loading amount on capacitance performances of MnO2/ordered mesoporous carbon composites

Abstract

MnO2/ordered mesoporous carbon (OMC) composites were prepared by a novel technique named as incipient wetness impregnation–hydrothermal method, which can prepare composites with relatively poorer crystallinity with high performance, and the effect of loading amount on the structure and capacitance performances of the composites was investigated. X-ray diffraction shows that the crystal phase of MnO2 becomes apparent as the loading amount increases. The Brunauer, Emmett, and Teller (BET) surface area and the total pore volume of the composites decrease with the increase in loading amount. The TEM shows that the host structure of OMC almost disappears after the formation of MnO2, and MnO2 particles can be detected on the surface of OMC at higher loading amount. The optimum loading amount is confirmed to be 48%, and the composite prepared at this loading amount exhibits 630·75 F g−1 specific capacitance in 1M LiOH electrolyte at the scan rate of 5 mV s−1, which is about three times of OMC. The composite prepared at this loading amount shows an excellent cycleability and promising prospect for the electrode material for supercapacitors.