Al_2O_3 Coating of Spherical LiNi_(0.8)Co_(0.2)O_2 for Li-ion Batteries

摘要

Spherical LiNi_(0.8)Co_(0.2)O_2 powders with particle size of 8～10μm were prepared based on controlled crystallization, and coated with Al_2O_3 by Al(OH)_3 sol, that was prepared from Al(NO_3)_3 and NaOH, at first time. SEM, XRD and surface element analysis showed that the nano-sized Al_2O_3 was coated uniformly on the surface of LiNi_(0.8)Co_(0.2)O_2 powder. At 25 ℃, the initial discharge capacity decreased from 160 to 149 mAh g~(-1) after coating of Al_2O_3. The initial discharge capacity decreased from 168 to 163 mAh g~(-1) after coating of Al_O at 55 ℃. After coating of Al_2O_3, the capacity retentions increased from 83.8% to 92.6% at the 50th cycle at 25℃, and from 36.3% to 90.8% at the 10th cycle at 55℃. This paves effective way to improve the performance of LiNi_(0.8)Co_(0.2)O_2 material for rechargeable lithium ion batteries.