A series of lithium nickel composite oxides LixNi1-xO (0 < x less than or equal to 0.3) were synthesized by rheological phase reaction method from LiOH.H2O and NiO. The structures were characterized by X-ray diffraction. The composite oxides are cubic with hexagonal super-lattices and their cell volumes have nice linear relationship to the lithium content. The reaction mechanism was investigated: at the beginning of reaction, LiNiO2 is formed rapidly from LiOH.H2O and NiO via oxidation and lithium inserting reaction, then LiNiO2 and excess NiO diffuse each other to form LixNi1-xO. The electrochemical properties of the compounds as anode materials for lithium ion batteries were discussed. (C) 2004 Elsevier B.V. All rights reserved.