The electrochemical property of ZrFx-coated Li[Ni1/3Co1/3Mn1/3]O2 cathode material

Electrochemical and thermal properties of pristine and ZrFx-coated Li[Ni1/3Co1/3Mn1/3]O-2 cathode materials are compared. The hydrothermal method is introduced for the fabrication of a uniform coating layer. The formation of a compact coating layer on the surface of pristine powder is observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From TEM-EDS and XPS analysis, it is inferred that the coating layer is ZrOxFy (zirconium oxyfluoride) form. The coated Li[Ni1/3Co1/3Mn1/3]O-2 electrodes have better rate capability and cyclic performance at high temperature compared with the pristine electrode. The thermal stability of the Li[Ni1/3Co1/3Mn1/3]O-2 electrode is also enhanced by the ZrFx coating. Such enhancements are due to the presence of a stable coating layer, which effectively suppresses the chemical instability ascribed to surface reaction between electrode and electrolyte. (C) 2009 Elsevier B.V. All rights reserved.