Cathode active materials with a composition of LiNi 0.7 Co 0.3 O 2 were synthesized by a solid-state reaction method at 850°C using Li 2 CO 3 , NiO or NiCO 3 , and Co 3 O 4 or CoCO 3 as the sources of Li, Ni, and Co, respectively. Electrochemical properties, structure, and microstructure of the synthesized LiNi 0.7 Co 0.3 O 2 samples were analyzed. The curves of voltage vs. x in Li x Ni 0.7 Co 0.3 O 2 for the first charge–discharge and the intercalated and deintercalated Li quantity Δx were studied. The LiNi 0.7 Co 0.3 O 2 sample synthesized from Li 2 CO 3 , NiO, and Co 3 O 4 had the largest first discharge capacity (127mAh/g), with a discharge capacity deterioration rate of 2.9mAh/g/cycle. The LiNi 0.7 Co 0.3 O 2 sample synthesized from Li 2 CO 3 , NiCO 3 , and Co 3 O 4 had the smallest capacity deterioration rate of 1.3mAh/g/cycle.