Cathode active materials with a composition of LiNi 0.7 Co 0.3 O 2 were synthesized by solid-state reaction at 800°C using Li 2 CO 3 or LiOH·H 2 O, NiO or NiCO 3 , and CoCO 3 or Co 3 O 4 as sources of Li, Ni, and Co, respectively. The electrochemical properties of the synthesized samples were then investigated. The structures of the synthesized LiNi 0.7 Co 0.3 O 2 samples were analyzed, and the microstructures of the samples were observed. 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 LiOH·H 2 O, NiO, and Co 3 O 4 had the largest first discharge capacity of 162mAh/g with a discharge capacity deterioration rate of 9.1mAh/g/cycle.