The effects of quenching treatment and AlF3 coating on LiNi0.5Mn0.5O2 cathode materials for lithium-ion battery

Submicron layered LiNi0.5Mn0.5O2 was synthesized via a co-precipitation and solid-state reaction method together with a quenching process. The crystal structure and morphology of the materials were investigated by X-ray diffraction (XRD), Brunauer-Emmett and Teller (BET) surface area and scanning electron microscopy (SEM) techniques. It is found that LiNi0.5Mn0.5O2 material prepared with quenching methods has smooth and regular structure in submicron scale with surface area of 0.43 m(2) g(-1). The initial discharge capacities are 175.8 mAh g(-1) at 0.1 C (28 mA g(-1)) and 120.3 mAh g(-1) at 5.0 C (1400 mA g(-1)), respectively, for the quenched samples between 2.5 and 4.5 V. It is demonstrated that quenching method is a useful approach for the preparation of submicron layered LiNi0.5Mn0.5O2 cathode materials with excellent rate performance. in addition, the cycling performance of quenched-LiNi0.5Mn0.5O2 material was also greatly improved by AlF3 coating technique. (C) 2009 Elsevier B.V. All rights reserved.