Synthesis and electrochemical properties of Li1.03Co0.1Mn1.9FzO4-z material for lithium-ion batteries
(College of Materials Science and Engineering, Sichuan University, Chengdu 610064, China)
Abstract: Li1.03Co0.10Mn1.90FzO4-z (z=0, 0.05, 0.10, 0.15 and 0.20) cathode materials were synthesized by solid-state reaction using Mn2O3, Li2CO3, Co2O3 and LiF as raw materials. The chemical compositions of Li1.03Co0.1Mn1.9FzO4-z were examined by inductively coupled plasma (ICP) and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Li1.03Co0.10Mn1.90O4 were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. It is found that the Li1.03 Co0.10Mn1.90FzO4-z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z≤0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount of F substitution for O element with Li+, Co3+ improves discharge capacity and structure stability of the materials. The Li1.03Co0.10Mn1.90F0.15O3.85 sample shows an initial discharge capacity of 111.0 mA·h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.
Key words: cathode materials; solid-state reaction; F-substitution; cycle performance