Structural Characterization and Electrochemical Performance of AIF(3)-coated LiNi0.45Mn0.45Co0.10O2 as Cathode Materials for Lithium Ion Batteries

摘要

In this paper, layered-LiNi0.45Mn0.45Co0.10O2 was prepared by co-precipitation and solid state reaction methods. The crystal structures and morphology of the materials were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The LiNi0.45Mn0.45Co0.10O2 sample delivered the initial discharge capacity of 167.2 mAh center dot g(-1) at 28 mA center dot g(-1) (0.1 C) in the range of 2.5 to 4.5 V, but the cycle-life performance was relatively bad, which could be remarkably improved by AlF3 surface coating. Electrochemical impedance spectroscopy (EIS) was used to understand the possible mechanisms of improved electrochemical properties by the AlF3 coating. The results demonstrate that these coating layers could protect the dissolution and corrosion of LiNi0.45Mn0.45Co0.10O2 cathode materials in electrolyte, stabilize its layered structure and reduce interface impedance. Therefore, the AlF3 coating technique is an effective method and tool to improve the electrochemical properties of LiNi0.45Mn0.45Co0.10O2 cathode material.