Electrochemical performance of cobalt-substituted lithium nickel oxides synthesized from lithium and nickel carbonates and cobalt oxide

LiNi1−yCoyO2 (y=0.1, 0.3 and 0.5) cathode materials were synthesized by a solid-state reaction method at different temperatures using Li2CO3 as a Li source, NiCO3 as a Ni source, and Co3O4 as a Co source. The electrochemical properties of the synthesized samples were then investigated. Structures of the synthesized LiNi1−yCoyO2 (y=0.1, 0.3 and 0.5) samples were analyzed, and microstructures of the samples were observed. Voltage vs. x in LixNi1−yCoyO2 curves for the first and second charge-discharge cycles and intercalated and deintercalated Li quantity Δx were studied. LiNi0.9Co0.1O2 synthesized at 800 °C had the largest first discharge capacity (152 mAh/g) and quite good cycling performance, with a discharge capacity of 146 mAh/g at n=5. It had a discharge capacity fading rate of 1.4 mAh/g/cycle.