Characteristics and electrochemical performance
of cathode material Co-coated LiNiO2 for Li-ion batteries
of cathode material Co-coated LiNiO2 for Li-ion batteries
(1. Laboratory on Solid State Ionics, University of Science and Technology Beijing, Beijing 100083, China;
2. Faculty of Materials and Technology Engineering, Jiangxi University of Science and Technology,
Ganzhou 341000, China)
2. Faculty of Materials and Technology Engineering, Jiangxi University of Science and Technology,
Ganzhou 341000, China)
Abstract: Spherical Ni(OH)2 powder coated with Co(OH)2 as raw material was mixed with LiOH to synthesize cathode material for lithium ion battery by using solid-state reaction. After sintered at temperature above 600 ℃, a solid solution with layer structure was formed. The result of XPS shows that it is a concentration gradient material with higher cobalt content at the surface, and the gradient decreases with increasing sintering temperature from 650 to 750 ℃. This new gradient material, called as Co-coated LiNiO2, exhibits excellent electrochemical performances for the cathode of Li-ion batteries in comparison with LiNiO2 and Co-doping LiNiO2. The discharge capacity of Co-coated LiNiO2 is over 180 mA•h/g and capacity decay per cycle is less than 0.07% when Co-coated LiNiO2 consisting of 92% nickel and 8% cobalt was sintered at the temperatures between 650－670 ℃. Though initial discharge capacity could be increased with higher sintering temperature, the cycle life would be reduced.
Key words: Li-ion battery; LiNiO2; LiCoO2; Ni(OH)2; Co(OH)2; cathode material; gradient cathode material; electrochemical performance