Highly monodisperse dumbbell-like yolk-shell manganese monoxide/carbon microspheres for lithium storage and their lithiation evolution

Herein, a novel dumbbell-like MnO/C microspheres with the yolk-shell structure, high monodispersity and regular morphology are successfully prepared by calcining precursors MnCO₃/RF microspheres under the vacuum condition. The effects of calcination temperature on morphology, carbonization degrees of carbon shells and pore properties of MnO/C microspheres are systematically investigated. Benefited from the yolk-shell structure, reasonable distribution of MnO nanocrystals and porous structure, MnO/C microspheres prepared at 550 °C exhibit high reversible capacity of 852.6 mAh/g at 1.32C over 500 cycles, long-term cycling stability (888.4 mAh/g at 2.64C over 400 cycles) and excellent rate performance (454.39 mAh/g at 6.60C and 253.28 mAh/g at 13.20C are remained). Furthermore, the lithiation evolution of MnO/C microspheres in the long-term cycling process at nano- and micro-scales are revealed and the LiCoO₂||MnO/C full cell present a great cyclic stability. Dumbbell-like MnO/C microspheres demonstrate potential applications for next-generation Li-ion batteries as anode materials profited from superior electrochemical performance.