Lithium nickel cobalt oxides synthesized from Li2CO3, NiO and Co3O4 by the solid-state reaction method

LiNi1−yCoyO2 (y = 0.1, 0.3 and 0.5) are synthesized by a solid-state reaction method at 800 °C and 850 °C from Li2CO3, NiO and Co3O4 as starting materials. The electrochemical properties of the synthesized LiNi1−yCoyO2 are investigated. The synthesized LiNi1−yCoyO2 has an α-NaFeO2 structure with a rhombohedral system (space group; R3¯m). Among all of the prepared LiNi1−yCoyO2 (y = 0.1, 0.3 and 0.5) samples, LiNi0.5Co0.5O2 calcined at 800 °C for 40 h has the best cycling performance (capacity fading rate 1.4 mAh/g/cycle) and a relatively large first discharge capacity (147.6 mAh/g). LiNi0.5Co0.5O2 calcined at 800 °C for 40 h has a large value of I0 0 3/I1 0 4. The low degree of displacement of the nickel and lithium ions in this sample is believed to have led to its relatively large first discharge capacity and best cycling performance.