Effect of Cr2O3 Coating on LiNi1/3Co1/3Mn1/3O2 as Cathode for Lithium-Ion Batteries

Cr2O3 was applied to modify the surface of LiNi1/3Co1/3Mn1/3O2 cathode material by a novel facile route. X-ray diffraction (XRD), scanning electron microscopy and x-ray photoelectron spectroscopy were used to characterize the structure, shape and composite of the obtained samples. Transmission electron microscope images clearly show that the uniform coating layer thicknesses are about 40 nm and 45 nm for 1 wt.% and 2 wt.% Cr2O3, respectively. At the high concentration (3 wt.%), the coating layer becomes heterogeneously distributed. After coating with 1 wt.%, 2 wt.%, and 3 wt.% Cr2O3, the initial specific discharge capacities decrease to 159.3 mAh g−1, 156.4 mAh g−1, and 152.7 mAh g−1 at 0.1 C, respectively. Despite an increasing charge transfer resistance for the Cr2O3 coating, a better rate capability and cycling ability have been obtained. High temperature-XRD (HT-XRD) data indicate that the thermal stability of the electrode material has also been obviously improved, which is especially helpful for LiNi1/3Co1/3Mn1/3O2 used as the cathode of lithium power batteries.