Improvement of electrochemical properties of LiNi1/3Co 1/3Mn1/3O2 by coating with V2O 5 layer

Abstract

The capacity fading and lower rate of layered cathode materials prohibited widely applications in lithium ion batteries. In this paper, V2O 5 was coated on the surface of LiNi1/3Co 1/3Mn1/3O2 to enhance its electrochemical performance at a voltage range of 2.8-4.5 V. The prepared materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The capacity retention at the 100th cycle have been increased from 62% to over 80% for the 3 wt.% V 2O5 coated sample. The rate performance has been improved by V2O5 coating which mainly because of the coating layer enhance the surface electronic/ionic transport. Cyclic voltammetry (CV) showed that the redox properties of the pristine sample have a more obvirous changes after chargedischarge cycles compared with the coated samples. Electrochemical impedance spectroscopy (EIS) results suggest that the V2O5 coating layer play an important role in suppressing the increase of cell impedance with cycling especially for the increase of charge-transfer resistance (Rct). © 2012 Elsevier B.V. All rights reserved.