Improving the electrochemical performance of LiNi0.5Co0.2Mn0.3O2 by double-layer coating with Li2TiO3 for lithium-ion batteries

摘要

The dual-layer Li2TiO3 coating of LiNi0.5Co0.2Mn0.3O2 (NCM523) compound has been successfully synthesized by a facile method for the first time. The EDS results show that the dual-layer coating is more uniform and smoother than the single-layer coating. Electrochemical tests show that the double-layer 0.5 mol % Li2TiO3-coated NCM can deliver an initial discharge capacity of 180 mAh g(-1) at 0.1 C in the voltage range of 2.8-4.3 V, with capacity retention of 94.2 % after 80 cycles at 0.5 C, while those of the pristine one are only 172.1 mAh g(-1)and 87 %, respectively. The enhanced electrochemical performance is attributed to the stable dual-layer Li2TiO3 that serves as a 3D-diffusion pathway for Li+ ions and a protective layer that prevents side reactions between electrode and electrolyte. Thus, the double-layer coating by Li2TiO3 is a promising method to improve rate capability and cycle performance of NCM523.