Effect of carbon coating on electrochemical performance of Li1.048Mn0.381Ni0.286Co0.286O2 cathode material for lithium-ion batteries

Carbon-coated layered oxide Li1.048Mn0.381Ni0.286Co0.286O2 is prepared by combining a co-precipitation and a direct current magnetron sputtering. TEM images show that the carbon layer is relatively well coated on the surface of oxide particles. The Li1.048Mn0.381Ni0.286Co0.286O2/C composite delivers an initial discharge capacity of 203.2 mAh g(-1) between 2.5 and 4.5 V at 0.1 C, and 94% of the initial discharge capacity can be retained after 100 cycles. Moreover, the carbon-coated oxide exhibits noticeable high-rate capacity of 145 mAh g(-1) at 5 C. much higher than the pristine one (103 mAh g(-1) at 5C). The improved discharge capacity and cycle performance are attributed to the carbon coating, which protects the Li-rich cathode material from reacting with the electrolyte and retarding the incrassation of SEI film on the surface of oxide particles. (C) 2011 Elsevier Ltd. All rights reserved.