Preparation and characterization of Li1.05[Ni0.35Co025Mn0.4]O2 as a cathode material for rechargeable lithium cells

A lithium insertion material Li-1.05[Ni0.35Co0.25Mn0.4]O-2 was synthesized by a sol- gel method. The structural and electrochemical properties of the sample were investigated using X- ray diffraction spectroscopy (XRD) and the galvanostatic charge- discharge method. Rietveld analysis of the XRD patterns shows this compound as having the alpha- NaFeO2 structure (R3m; a = 2.8670 (4) angstrom, and 14.279 (3) angstrom in hexagonal setting.Li-1.05[Ni0.35Co0.25Mn0.4]O-2 has a discharge capacity of 164 mAh/ g in the voltage range 2.8- 4.5 V vs Li/ Li+, a stable capacity on cycling, and good rate capability in the current range 0.1- 4.0 C. When the voltage range is increased to 2.8- 4.8 V, it yields a capacity of 187 mAh/ g, but exhibits a significant loss of capacity during cycling. The results indicate that this novel cathode material should be useful for lithium- ion cells because it has a lower cost than LiCoO2- containing cells, and high performance. (c) 2005 The Electrochemical Society.