Abstract: LiCo1/3Ni1/3Mn1/3O2 was coated by a layer of Y2O3 via a simple method. The bared sample was immersed into Y(NO3)3·6H2O solution and then calcined at a certain temperature to get the coated material. The coated and bared LiCo1/3Ni1/3Mn1/3O2 meterials were characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), cyclic voltammetry (CV), and galvanotactic charge-discharge test. It was showed that Y2O3 existed only on the surface, and had no effect on the crystal structure; the LiCo1/3Ni1/3Mn1/3O2 coated with Y2O3 exhibited better capacity retention than the bared LiCo1/3Ni1/3Mn1/3O2 in the higher cutoff voltage and had higher thermal stability. CV results suggested that the Y2O3 coating suppressed the phase transitions and prevented the surface of cathode materials fromdirect contact with the electrolyte.

Key words: LiCo1/3Ni1/3Mn1/3O2, Y2O3, Coating, Lithium-ion battery