Investigation of ordered mesoporous carbon@MnO core–shell nanospheres as anode material for lithium-ion batteries

Abstract

Here, we present a design of core–shell structured carbon@MnO composite nanospheres and investigate its electrochemical performance as an anode material for lithium-ion batteries. The core–shell carbon@MnO composite nanospheres are obtained from the intermediate product of carbon@MnO2 nanospheres by coating a MnO2 layer over the surface of the mesoporous carbon cores, followed by thermal treatment in an inert atmosphere. The morphology and crystal phase of the obtained nanospheres are examined, and the electrochemical properties as a lithium-ion battery anode material are studied. The results demonstrate that the ordered mesoporous carbon@MnO electrode shows remarkable enhancements in lithium storage capacity, rate capability and cycling stability, delivering an average capacity of 572 mAh g−1 at 500 mA g−1 over 1000 charge/discharge cycles. The morphology and phase of the core–shell carbon@MnO electrode material after extended cycling are examined by transmission electron microscopy and X-ray diffraction, which indicate the nanocrystalline rather than amorphous property of the cycled electrode. As MnO is a conversion-type electrode material, the potential polarization of the carbon@MnO composite electrode is also investigated, which exhibits a unique evolution as cycling proceeds.