Highly reversible conversion-capacity of MnOx-loaded ordered mesoporous carbon nanorods for lithium-ion battery anodes

초록

An ordered mesoporous carbon (OMC) with a nanorod-shaped morphology and enhanced graphitic character was employed as an ideal support for MnOx (major phase of Mn3O4 with a small portion of MnO) nanocrystals which possess a high theoretical conversion capacity as a Li-ion battery anode. The MnOx/OMC nanocomposite was prepared by a simple wet-impregnation of Mn(NO3)(2) aqueous solution onto OMC nanorods followed by thermal treatment at 450 degrees C in an Ar flow. The electrochemical properties of MnOx/OMC were investigated in comparison to those of bare OMC and a commercial graphite as an anode for Li-ion batteries. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, N-2 adsorption-desorption analysis, X-ray photoelectron spectroscopy, and thermogravimetric analysis revealed that 3-30 nm MnOx nanocrystals at a high loading of 68.4 wt% were formed and well dispersed in the pore structure of OMC nanorods. The MnOx/OMC exhibited a high reversible capacity (>950 mAh g(-1)) after 50 deep charge-discharge cycles with excellent cycling stability, Coulombic efficiency and rate capability. As an anode for Li-ion batteries, the incorporation of insulating high density MnOx nanocrystals into OMC nanorods showed synergistic benefits of high volumetric capacity as well as specific capacity, and small redox voltage hysteresis compared to OMC nanorods.

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