Nitrate-Melt Synthesized HT-LiCoO2 as a Superior Cathode-Material for Lithium-Ion Batteries

An electrochemically-active high-temperature form of LiCoO2 (HT-LiCoO2) is prepared by thermally decomposing its constituent metal-nitrates at 700 oC. The synthetic conditions have been optimized to achieve improved performance with the HT-LiCoO2 cathode in Li-ion batteries. For this purpose, the synthesized materials have been characterized by powder X-ray diffraction, scanning electron microscopy, and galvanostatic charge-discharge cycling. Cathodes comprising HT-LiCoO2 exhibit a specific capacity of 140 mAhg with good capacity-retention over several charge-discharge cycles in the voltage range between 3.5 V and 4.2 V, and can sustain improved rate capability in contrast to a cathode constituting LiCoO2 prepared by conventional ceramic method. The nitrate-melt-decomposition method is also found effective for synthesizing Mg-/Aldoped HT-LiCoO2; these also are investigated as cathode materials for Li-ion batteries.