SYNTHESIS OF ORTHORHOMBIC LiMnO2 BY HYDROTHERMAL PROCESS

This work synthesised layered structural orthorhombic LiMnO2 powder via a hydrothermal process. The influences of hydrothermal temperature (tr°), reaction time (tht), molar concentration of LiOH.H2O in aqueous solutions (CLH), and the ratio of Mn2O3 powder (xr/t) were investigated. A high-purity LiMnO2 powder was successfully synthesised using hydrothermal synthesis at CLH = 4M, tht = 8 h, tr° = 180 °C, and xr/t = 0.9. The synthesis LiMnO2 powders have layer structure, and the planar density calculations indicated that the (021) planes had a lower average planar density than those of (100) and (010) planes, which led to a faster crystal growth on (021) planes. Moreover, single crystals of LiMnO2 were pseudo-hexagonal also due to the lower average planar density of (221) planes compared to that of (021) planes, which made the crystal grow faster on (221) planes.