Surface modification of LiCo1/3Ni1/3Mn1/3O2 with Y2O3 for lithium-ion battery

The surface of LiCo1/3Ni1/3Mn1/3O2 cathode material was coated with 10 wt% Y2O3 via a simple method to improve the cycling performance for lithium-ion batteries. Cyclic voltammetry showed Y2O3-coating inhibited structural change of LiCo1/3Ni1/3Mn1/3O2 and reaction with the electrolyte on cycling.The Y2O3 coated material showed a higher capacity with good cyclability. The discharge capacity of coated sample was 137.5 mAh g(-1) at 2.0 mA cm(-2) while that of bared one was only 116.2 mAh g(-1). The rate of capacity decrease after 20 cycles for the coated sample was 0.7%, much smaller than that of the bared one (2.8%). X-ray photoelectron spectroscopy (XPS) data represented that the presence of two different environmental O1s ions corresponded to the surface-coated Y2O3 and core material. ICP-OES and EIS displayed the coating layer could protect the LiCo1/3Ni1/3Mn1/3O2 from being corroded by the electrolyte and benefit to decrease the cathode charge-transfer resistance at delithiated state. (C) 2008 Elsevier B.V. All rights reserved.