Molten salt synthesis of LiMn 2O 4 using chloride–carbonate melt

Abstract

Lithium manganese oxide powders have been successfully prepared by molten salt synthesis (MSS) route using the eutectic mixture of LiCl, MnCl 2·4H 2O and Li 2CO 3 salts. The synthesis was performed at 700 °C using an electrical resistance furnace. The crystalline powders were characterized using TGA/DTA, XRD, FT-IR, AAS, CHNS, EDAX, EPR and SEM analyses. The lattice constant value for LiMn 2O 4 is a = 8.1834 Å. The FT-IR spectrum, exhibits the high-frequency bands located at 611 and 500 cm −1 are associated with the asymmetric stretching modes of the MnO 6 group. The Raman spectrum shows a strong band located at 644 cm −1 may be assigned to A 1g mode, which corresponds to the symmetric Mn–O stretching vibration of MnO 6 groups. The average particle size of LiMn 2O 4 crystals is found to be between 25 and 35 μm. It is concluded that the possibility of preparing fine crystalline LiMn 2O 4 powders with appreciable purity using low temperature molten salt synthesis route.