Synthesis and characterization of Li(Ni 1/3Co 1/3Mn 1/3) 0.96Si 0.04O 1.96F 0.04 as a cathode material for lithium-ion battery

Abstract

The layered cathode materials of LiNi 1/3Co 1/3Mn 1/3O 2 were prepared at 770 °C under oxygen atmosphere using the precursor of (Ni 1/3Co 1/3Mn 1/3)(OH) 2 by co-precipitated method, and doped by silicon and fluorine to improve their electrochemical properties. The effects of Si–F co-substitution on the structure, electrochemical performance of Li(Ni 1/3Co 1/3Mn 1/3)O 2 compounds was studied detail in this paper. X-ray diffraction (XRD) analysis suggests that Li(Ni 1/3Mn 1/3Co 1/3) 0.96Si 0.04O 1.96F 0.04 has a well-layered structure after doping with the anion–cation. Scanning electron microscopy (SEM) shows the morphologies of the samples were also significantly uniform and consisted of finer primary particles with a narrow particle size between 0.1 μm and 0.2 μm. Its electrochemical performance was investigated by galvanostatic charge–discharge experiment and electrochemical impedance spectrum (EIS). The results exhibit that the first discharge capacity is enhanced and cycling property is improved. Composite doping reduces electrode polarization and restrains the increase of the electrochemical reaction impedance of cathode during cycling as well.