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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 32, Number 8
BKCSDE 32(8)
August 20, 2011 

Synthesis and Electrochemical Characterization of Silica-Manganese Oxide with a Core-shell Structure and Various Oxidation States
Seong-Hyeon Ryu, Seung-Gi Hwang, Su-Ryeon Yun, Kwon-Koo Cho, Ki-Won Kim, Kwang-Sun Ryu*
Silica-manganese oxide, Core-shell structure, Supercapacitor, Electrode, Oxidation state
Silica-manganese oxides with a core-shell structure were synthesized via precipitation of manganese oxides on the SiO2 core while varying the concentration of a precipitation agent. Elemental analysis, crystalline property investigation, and morphology observations using low- and high-resolution electron microscopes were applied to the synthesized silica-manganese oxides with the core-shell structure. As the concentration of the precipitating agent increased, the manganese oxide shells around the SiO2 core sequentially appeared as Mn3O4 particles, Mn2O3+Mn3O4 thin layers, and α-MnO2 urchin-like phases. The prepared samples were assembled as electrodes in a supercapacitor with 0.1 M Na2SO4 electrolyte, and their electrochemical properties were examined using cyclic voltammetry and charge-discharge cycling. The maximum specific capacitance obtained was 197 F g−1 for the SiO2-MnO2 electrode due to the higher electronic conductivity of the MnO2 shell compared to those of the Mn2O3 and Mn3O4 phases.
2683 - 2688
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