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)center dot 2H(2)O, Ni(Ac)(2)center dot 4H(2)O, Co(Ac)(2)center dot 4H(2)O, Mn(Ac)(2)center dot 4H(2)O(Ac = acetate), LiF and excess H2C2O4 center dot 2H(2)O 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 R (3) over barm. The FESEM images show that the primary particle size of LiNi1/3Co1/3Mn1/3O1-zFz gradually increases with increasing fluorine content. Though the fluorine-substituted LiNi1/3Co1/3Mn1/3O1-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. (c) 2006 Elsevier B.V. All rights reserved.