Structural and electrochemical properties of Li-Ni-Co oxides synthesized by wet chemistry via a succinic-acid-assisted technique

Lithiated metal oxides LiCo1-xNiyO2 were synthesized by a sol-gel method using succinic acid as chelating agent. Microcrystalline materials were formed by calcination in oxygen at 800 degreesC. The physicochemical properties of the powders (crystallinity, lattice constants, size grain) has been investigated in the compositional range 0 less than or equal to y less than or equal to 1. Structural studies show that a layered single phase was obtained. The local cationic environment has been studied by Raman and FTIR spectroscopy. The changes in the vibrational spectra are well related to those observed by X-ray diffraction. It is shown that the lithium predominant layers are preserved in the entire range of substitution. Pelletized LiCo1-yNiyO2 powders (0.2 less than or equal to y less than or equal to 1.0) were tested in Li//LiCo1-yNiyO2 cells by galvanostatic titration. These cells have an initial capacity of 140 mAh/g in the voltage range 2.8-4.2 V and show attractive charge-discharge profiles upon cycling. (C) 2001 Elsevier Science Ltd. All rights reserved.