LiNi0.70Co0.15Al0.15O2 has been synthesized by a coprecipitation method. The structural characterization by X-ray and neutron diffraction, associated with a Rietveld analysis, has confirmed a segregation tendency for cobalt and aluminum ions. However, a quasi-ideal lamellar structure was obtained for this phase, with less than 1% extra-nickel ions in the interslab space. Cycling tests have shown a very good cycling stability with a high reversible capacity of about 150 mAh/g in the 3-4.15 V range at the C/20 rate. (C) 2003 Elsevier Science B.V. All rights reserved.