We present an in situ reduction method to synthesize a novel structured MnO_2/mesoporous carbon (MnC) composite.MnO_2 nanoparticles have been synthesized and embedded into the mesoporous carbon wall of CMK-3 materials by the redox reaction between permanganate ions and carbons.Thermogravimetric analysis (TG),X-ray photoelectron spectrum (XPS),X-ray diffraction (XRD),nitrogen sorption,transmission electron microscopy (TEM),and cyclic voltammetry were employed to characterize these composite materials.The results show that different MnO_2 contents could be introduced into the pores of CMK-3 treated with different concentrations of potassium permanganate aqueous solution,while retaining the ordered mesostructure and larger surface area.Increasing the MnO_2 content did not result in a decrease in pore size from the data of nitrogen sorption isotherms,indicating that MnO_2 nanoparticles are embedded in the pore wall,as evidenced by TEM observation.We obtained a large specific capacitance over 200 F/g for the MnC composite and 600 F/g for the MnO_2,and these materials have high electrochemical stability and high reversibility.
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State Key Laboratory of High Performance Ceramics and Superfine Microstructures,Shanghai Institute of Ceramics,Chinese Academy of Sciences,1295 DingXi Road,Shanghai 20005095,People's Republic of China;
