Development of structural stability and the electrochemical performances of 'La' substituted spinel LiMn2O4 cathode materials for rechargeable lithium-ion batteries

The LiLaxMn2-xO4 (x = 0.00 to 0.10) cathode materials for rechargeable lithium ion batteries were synthesized by simple sol-gel technique using aqueous solutions of metal nitrates and succinic acid as the chelating agent. The gel precursors of metal succinates were dried in vacuum oven for 10 h at 110 degrees C. After drying, the gel precursors were ground and heated at 900 degrees C. The structural characterization was carried out by X-ray powder diffraction and Laser Raman spectroscopy. The sample exhibited a well-defined spinel structure and the lattice parameter was linearly increased with the increasing lanthanum contents in LiLaxMn2-xO4. Surface morphology of the synthesized materials was determined by Scanning electron microscope and it was found that the cathode materials consisted of highly-ordered single crystalline particles with cubic spinel structure. Electrochemical properties were characterized by the assembled test cells using Galvanstatic charge/discharge studies which were carried out at a current rate 0.1C and Cyclic voltammetry was carried out in the potential range of 2.75 to 4.5 V at a scan rate 0.1 mVs(-1). Among them, lanthanum doped spinel LiLa0.05Mn1.95O4 has improved the structural stability, high reversible capacity and excellent electrochemical performance of rechargeable lithium batteries. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.