Studies on the electrochemical properties of nickel-rich Li1.02Ni0.6Co0.2Mn0.2O2 materials for lithium-ion batteries via cerium modifications

Abstract

This work reports improved cycle performance and rate properties of Ni-rich layered oxide cathode material. Trace amounts of Ce were used to modify the crystal structure and surface of the Ni-rich Li1.02Ni0.6Co0.2Mn0.2O2. The structure and electrochemical performances of the materials were characterized using XRD, SEM, TEM, XPS, ICP, charge-discharge testing, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the peak has a slight shift after Ce modification of the material, showing that some Ce entered the crystal lattice. TEM showed that the remainder of the Ce forms a 8-nm thick coating layer on the surface of the Li1.02Ni0.6Co0.2Mn0.2O2 material. As a result, the Ce-modified sample exhibited superior electrochemical performance. The initial discharge capacity of the Ce modified sample was 161 mAh/g at 1C, the discharge capacity was still kept 84.6% after 200 cycles.