Al₂O₃-coated Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ nanotubes as cathode materials for high-performance lithium-ion batteries

Li-rich manganese-based layered cathode Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ (LMNCO) nanotubes are synthesized by electrospinning and surface coated with different amounts of amorphous Al₂O₃. The effects of the coating content of Al₂O₃ on the structural and electrochemical performances of LMNCO nanotubes are investigated systematically. The results show that the morphologies and structures of the samples exhibit no apparent changes after being coated with Al₂O₃. Electrochemical tests indicate that the Al₂O₃-coated LMNCO nanotubes exhibit obviously enhanced electrochemical performances. The initial coulombic efficiency of surface modified LMNCO nanotubes increased from 74.9% to 85.2%, and the modified LMNCO nanotubes have a high capacity retention of 97.6% after 90 cycles at 1C. The improved electrochemical performances of the coated samples are attributed to the protective function of the uniform Al₂O₃ coating and the three-dimensional Li⁺ diffusion channel in the spinel interface layer.