Surface design with spinel LiMn1.5Ni0.5O4 for improving electrochemical properties of LiNi0.5Co0.2Mn0.3O2 at high cut-off voltage

Abstract

Spinel LiNi0.5Mn1.5O4 is successfully coated on the surface of LiNi0.5Co0.2Mn0.3O2 cathode material by sol-gel method. The results show that the spinel LiNi0.5Mn1.5O4 has been successfully coated on the surface of LiNi0.5Co0.2Mn0.3O2 and exhibits a good electrochemical performance at high cut-off voltage (4.6V), showing initial discharge capacity of 192.1mAhg−1 and retains 92.4%after 100 cycles. The rate capability results show that the reversible capacity retention of LiNi0.5Co0.2Mn0.3O2 increases from 84.1% to 90.6% after being coated with LiNi0.5Mn1.5O4. Electrochemical impedance spectroscopy (EIS) reveals that the coating layer can protect LiNi0.5Co0.2Mn0.3O2 from HF attack, reduce the charge transfer resistance and favor the lithium diffusion of the electrode.