Li[Mn1/3Co1/3Ni1/3]O-2 cathode material for lithium ion batteries was coated by CaF2 via wet coating strategy. The CaF2-coated Li[Mn1/3Co1/3Ni1/3]O-2 were analyzed by X-ray diffraction spectra (XRD). the scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDAX) to confirm the structure and morphology of cathode material. Cyclic voltammetry and cycling charge-discharge measurements were carried out to study the electrochemical performance of bare and coated samples, as well as the optimal coating dosage. Comparison tests have found that the capacity retention is 67.9% for bare sample and 93.5% for 1.0 wt.% CaF2-coated sample. In summary, the CaF2 coating strategy benefits the cycling performance of Li[Mn1/3Co1/3Ni1/3]O-2 cathode material, and the optimal dosage of coating agent is 1.0 wt.%. (C) 2011 Elsevier Ltd. All rights reserved.