Electrochemical studies on Al₂O₃-coated spinel LiMn₂O₄ for lithium ion batteries

Spinel LiMn₂O₄ was synthesized via a solid state reaction, and modified with Al₂O₃ thin layers by a chemical deposition method. The electrochemical performances of the as-prepared samples were investigated with cyclic voltammetry (CV) and charge-discharge test. It is found that the Al₂O₃-coated LiMn ₂O₄ help dramatically retaining the discharge capacity upon long-term cycling. The influences of the heat-treating temperature and the coating amount are discussed and compared. The optimized sample is 1% Al ₂O₃/LiMn₂O₄ heat-treated at 500°C, which has an initial discharge capacity of 116mAh/g, and a very slight capacity loss of 1.7% at the 50th cycle.