Role of Hydrothermal parameters on phase purity of orthorhombic LiMnO₂ for use as cathode in Li ion battery

Orthorhombic LiMnO₂ (o-LiMnO₂) was prepared under hydrothermal conditions using sol-gel derived Mn₂O₃ and LiOH as precursors and the effects of hydrothermal reaction parameters such as reaction temperature and LiOH and Mn₂O₃ concentrations on the phase purity of o-LiMnO₂ were studied. The as-prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and galvanostatic charge-discharge tests. Phase purity of o-LiMnO₂ was affected by hydrothermal temperature and LiOH and Mn₂O₃ concentrations. High LiOH concentration facilitated the synthesis of pure phase o-LiMnO₂. Low reaction temperature, lower than 140 °C, did not lead to the formation of pure phase of o-LiMnO₂. Galvanostatic charge-discharge test results showed that pure o-LiMnO₂ had larger discharge capacity than the mixed phases of o-LiMnO₂ and Li₂MnO₃. However, the cycling performance of the mixed phases of o-LiMnO₂ with Li₂MnO₃ was found to be better than that of pure o-LiMnO₂.