Synthesis of LiNi1/3Co1/3Mn1/3O2−zFz cathode material from oxalate precursors for lithium ion battery

The layered LiNi1/3Co1/3Mn1/3O2−zFz (0 ≤ z ≤ 0.12) cathode materials were synthesized from oxalate precursors by a simple self-propagating solid-state metathesis method with the help of the ball milling and the following calcination. Li(Ac)·2H2O, Ni(Ac)2·4H2O, Co(Ac)2·4H2O, Mn(Ac)2·4H2O(Ac = acetate), LiF and excess H2C2O4·2H2O were used as starting materials without any solvent. The structural and electrochemical properties of the prepared LiNi1/3Co1/3Mn1/3O2−zFz were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and electrochemical measurements, respectively. The XRD patterns indicate that all samples have a typical hexagonal structure with a space group of R3¯m. The FESEM images show that the primary particle size of LiNi1/3Co1/3Mn1/3O2−zFz gradually increases with increasing fluorine content. Though the fluorine-substituted LiNi1/3Co1/3Mn1/3O2−zFz have lower initial discharge capacities, a small amount of fluorine-substituted LiNi1/3Co1/3Mn1/3O2−zFz (z = 0.04 and 0.08) exhibit excellent cycling stability and rate capability compared to fluorine-free LiNi1/3Co1/3Mn1/3O2.

The effects of fluorine substitution on the discharge characteristics of the prepared LiNi1/3Co1/3Mn1/3O2−zFz cathode materials in voltages of 3.0–4.6 V at different discharge rate. Figure optionsDownload as PowerPoint slide