We present the synthesis,characterization and electrode behaviour of LiA1(y)Co(1-y)O(2) (0.0 less than or equal to y less than or equal to 0.3) oxides prepared by the citrate route. The phase evolution was studied as a function of the aluminium substitution and the modification on the intercalation and deintercalation of Li ions. Characterization methods include X-ray powder diffraction (XRD), thermogravimetry analysis (TG-DTA), scanning electron microscopy (SEM), Raman scattering (RS) and Fourier transform infrared (FTIR) spectroscopy. Samples belong to the LiCoO2-LiA1O(2) solid solution and have the layered alpha-NaFeO2 structure (R (3) over barm space group). Raman scattering and FT-infrared vibrational spectroscopies indicate that the vibrational mode frequencies and relative intensities of the bands are sensitive to the covalency of the (Co, A1)O-2 slabs. SEM micrographs show that the particle size of the LiA1(y)Co(1-y)O(2) powders ranges in the submicronic domain with a narrow grain-size distribution. The overall electrochemical capacity of the LiAlyCo1-yO2 oxides have been reduced due to the sp metal substitution, however, a more stable charge-discharge cycling performances have been observed when electrodes are charged up to 4.3 V as compared to the performance of the native oxide. For such a cut-off voltage, the charge capacity of the Li//LiA1(0.2)Co(0.8)O(2) cell is ca. 118 mAh g(-1). Kinetics were characterized by the galvanostatic intermittent titration technique (GITT). Aluminium substitution provides an increase of the chemical diffusion coefficients of Li+ ions in the LiA1(y)Co(1-y)O(2) matrix. Differences and similarities between LiCoO2 and A1-substituted oxides are discussed there from. (C) 2002 Elsevier Science B.V. All rights reserved.