Synthesis and electrochemical properties of lithium cobalt oxides prepared by molten-salt synthesis using the eutectic mixture of LiCl-Li₂CO₃

Lithium cobalt oxide powders have been successfully prepared by a molten-salt synthesis (MSS) method using a eutectic mixture of LiCl and Li₂CO₃ salts. The physico-chemical properties of the lithium cobalt oxide powders are investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), particle-size analysis and charge-discharge cycling. A lower temperature and a shorter time (approximately 700 °C and 1 h) in the Li:Co = 7 system are sufficient to prepare single-phase HT-LiCoO₂ powders by the MSS method, compared with the solid-state reaction method. Charge-discharge tests show that the lithium cobalt oxide prepared at 800 °C has an initial discharge capacity as high as 140 mA h g^-1, and 100 mA h g^-1 after 40 cycles. The dependence of the synthetic conditions of HT-LiCoO₂ on the reaction temperature, time and amount of flux with respect to starting oxides is extensively investigated.