Samples of LiNi0.85 CO0.15-2x(TiMg)(x)O-2 (X = 0.0125, 0.025 and 0.05), prepared by solid state reaction at 725degreesC for 24h from LiOH.H2O, Ni2O3, Co2O3,TiO2 andMg(OH)(2) under oxygen flow, were characterized by TG-DTA, XRD and electrochemical tests. LiNiO2 simultaneously doped by Co-Ti-Mg has been tried to improve the cathode performance. The results show that co-doping (x = 0.025) definitely has a large beneficial effect in increasing the capacity (182.7 mA h g(-1) of the first discharge capacity for LiNi0.85 Co-0.10(TiMg)(0.025)O-2) and cycling behavior (170.6 mA h g(-1) after 15 cycles). Differential capacity versus voltage curves indicate the co-doped LiNiO2 show suppression of the phase transitions as compared with LiNiO2. (C) 2004 Elsevier B.V. All rights reserved.