Nanocrystalline LiMn2O4 thin film cathode material prepared by polymer spray pyrolysis method for Li-ion battery

Nanocrystalline cubic spinel lithium manganese oxide thin film was prepared by a polymer spray pyrolysis method using lithium acetate and manganese acetate precursor solution and polyethylene glycol-4000 as a polymeric binder. The substrate temperature was selected from the thermogravimetric analysis by finding the complete crystallization temperature of LiMn₂O₄ precursor sample. The deposited LiMn₂O₄ thin films were annealed at 450, 500 and 600 °C for 30 min. The thin film annealed at 600 °C was found to be the sufficient temperature to form high phase pure nanocrystalline LiMn₂O₄ thin film. The formation of cubic spinel thin film was confirmed by X-ray diffraction study. Scanning electron microscopy and atomic force microscopy analysis revealed that the thin film annealed at 600 °C was found to be nanocrystalline in nature and the surface of the films were uniform without any crack. The electrochemical charge/discharge studies of the prepared LiMn₂O₄ film was found to be better compared to the conventional spray pyrolysed thin film material.