Synthesis of mesoporous TiO2@C@MnO2 multi-shelled hollow nanospheres with high rate capability and stability for lithium-ion batteries

Abstract

While TiO₂ is regarded as a good anode material for Li ion storage because of its excellent cycling stability, high safety and low cost, its practical applications for Li-ion batteries (LIBs) still present a great challenge due to its poor conductivity and low theoretical capacity. A hybrid nanostructured electrode design offers opportunities to circumvent these drawbacks. Herein, we report a cost-effective strategy for the fabrication of mesoporous TiO₂@C@MnO₂ multi-shelled hollow nanospheres as LIBs anodes. The multiple-shelled structure effectively couples the electrochemical functionality of TiO₂, MnO₂ and C including: the excellent stability of TiO₂, the large capacity of MnO₂, and the high electronic conductivity of the carbon layer. Meantime, the mesoporous shells and hollow nanostructure design not only provide fast Li⁺ transportation throughout the electrode, but also can further buffer the volume expansion of electrodes during charge/discharge. As a result, TiO₂@C@MnO₂ multi-shelled hollow nanospheres exhibit an enhanced charge/discharge capacity (506.8 mA h g⁻¹ at the rate of 0.3C after 100 cycles) and excellent rate performance (278.7 mA h g⁻¹ at 3C after 200 cycles), much better than the individual parts. Our work on hybrid hollow structures with multiple shells demonstrates an efficient way to realize the enhancement of the electrochemical performance of LIB anode materials, thus casting light on the development of advanced anode materials for next-generation, high-performance LIBs.