MnO₂-Embedded-in-Mesoporous-Carbon-Wall Structure for Use as Electrochemical Capacitors

Abstract

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.

Review of Electrochemical Capacitors Based on Carbon Nanotubes and Graphene

“…The widely used metal oxides nanostructured materials involve MnO 2 [26,27], RuO 2 [28,29], MoO 3 [30], Co 3 O 4 [31], VOx [32], and so forth.…”

Fabrication of CNT/CMK3 Carbon Composites with High Electrical/Thermal Conductive Properties

“…As an example of the modified MC electrode, Dong et al 22 presented an in situ reduction method to synthesize a MnO 2 /MC composite (MnC). They obtained a large specific capacitance of more than 200 F/g for a MnC composite with high electrochemical stability and reversibility.…”

Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

“…Therefore, many researchers are focused on improving the energy density of supercapacitors while maintaining their high power density [6][7][8]. The energy storage of pseudocapacitors is based on the Faraday reactions occurring at the surface of electroactive materials, such as RuO 2 , MnO 2 , IrO 2 , and Co 3 O 4 [9][10][11][12][13], and the energy density is higher than carbon based electric double-layer capacitors. Transition metal oxides provide higher specific capacitance and energy density than carbon materials [14,15], which have been considered as promising pseudocapacitive materials.…”