Enhanced Electrochemical Performance of Li[Li0.2Ni0.2Mn0.6]O-2 Modified by Manganese Oxide Coating for Lithium-Ion Batteries

Li-rich layered cathode material Li[Li0.2Ni0.2Mn0.6]O-2 was modified by manganese oxide coating via a simple deposition and heat-treatment process. The HRTEM images and the XPS analysis demonstrated that the surface of Li[Li0.2Ni0.2Mn0.6]O-2 was covered by continuous manganese oxide layer, with about 10 nm thickness. The electrochemical performance is improved greatly, especially the rate capability. The composite coated with 4 wt % manganese oxide showed high reversible capacity of 210 mAh g(-1) after 50 cycles at 2 C (400 mA g(-1)), compared with 77 mAh g(-1) of the pristine. It is believed that surface modification of Li[Li0.2Ni0.2Mn0.6]O-2 with manganese oxide coating exhibits a convenient approach for a large-scale production. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3496402] All rights reserved.