Facile combustion synthesis of amorphous Al2O3-coated LiMn2O4 cathode materials for high-performance Li-ion batteries

Abstract

Amorphous Al₂O₃-coated spinel LiMn₂O₄ cathode materials were prepared via a simple combustion method at a low temperature using glucose as a fuel. The morphology and structure of all samples were characterized by X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The thickness of the amorphous Al₂O₃-coating is about 5 nm. Moreover, the typical spinel structure of the LiMn₂O₄ exhibits no change after coating Al₂O₃. Electrochemical characterization showed that the Al₂O₃-coating can improve the cycling and high current rate performance of the LiMn₂O₄; in particular, the 1.0 wt% Al₂O₃-coated LiMn₂O₄ cathode revealed a high initial discharge capacity of 120.4 mA h g⁻¹ and a good cycling stability with a capacity retention of 93.52% after 100 cycles at 1 C. Moreover, an excellent high rate performance with an initial capacity of 84.2 mA h g⁻¹ and a capacity retention of 76.96% after 1000 cycles are also obtained at 10 C.