Electrochemical characteristics of LiNi0.7Co0.3O2 synthesized at 850 °C from carbonates or oxides of Li, Ni, and Co

Cathode active materials with a composition of LiNi0.7Co0.3O2 were synthesized by a solid-state reaction method at 850 °C using Li2CO3, NiO or NiCO3, and Co3O4 or CoCO3 as the sources of Li, Ni, and Co, respectively. Electrochemical properties, structure, and microstructure of the synthesized LiNi0.7Co0.3O2 samples were analyzed. The curves of voltage vs. x in LixNi0.7Co0.3O2 for the first charge–discharge and the intercalated and deintercalated Li quantity Δx were studied. The LiNi0.7Co0.3O2 sample synthesized from Li2CO3, NiO, and Co3O4 had the largest first discharge capacity (127 mAh/g), with a discharge capacity deterioration rate of 2.9 mAh/g/cycle. The LiNi0.7Co0.3O2 sample synthesized from Li2CO3, NiCO3, and Co3O4 had the smallest capacity deterioration rate of 1.3 mAh/g/cycle.