Abstract: The spinel LiMn2O4 synthesized by the method of solid-state reaction was modified with aluminum oxide through the heterogeneous nucleation process. The pristine and surface-modified spinel LiMn2O4 were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM) and particle size analysis. Effects of the surface-modification and preparation conditions on the cycleability and the rate capability were studied. The initial capacity of unmodified LiMn2O4 was 86.5 mA•h•g－1 and the capacity fade was 26.3％ after 50 cycles. The initial capacities of LiMn2O4 modified with 0.5％ and 1％(w) aluminum oxide were 96.0 mA•h•g－1 and 80.1 mA•h•g－1, and the capacity fades were 7.0％ and 5.6％, respectively. The results showed that the cycling life of LiMn2O4 was clearly improved by modification of aluminum oxide through the process of heterogeneous nucleation. With the increase of aluminum oxide, the cycling life increases, however, the capacity obviously decreases. The process of heterogeneous nucleation showed some special characters, such as the homogeneous coating. It is more suitable for the surface-modification of LiMn2O4.

Key words: Lithium ion battery, Spinel, Lithium manganese oxide, Surface modification, Heterogeneous nucleation