Microstructure and Electrochemical Properties of LiNi_(1/3)CO_(1/3)Mn_(1/3)O_2 Coated with Al_2O_3 Film

LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 is considered as a new-generation cathode material for lithium ion batteries.Al_2O_3 film was coated on the surface of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 in order to prevent irreversible reactions between cathode and electrolytes.The structure analysis indicates that the Al_2O_3 film is amorphous with thickness of about 100nm,the core material has a hexagonal structure.The experiment results show that Al_2O_3 coating is effective to improve overcharge capability and cycle stability.The capacity retention of the coated LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 is increased by 11.5% compared with that of a blank sample after 50 charge-discharge cycles at the cutoff voltage of 3.0-4.5V and 1C rate.