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.