A series of spinel-structured LiMn2-x-yNixCryO4 have been prepared and their electrochemical performances as 5-V cathode materials for lithium ion batteries are evaluated. The synthesis reactions for these materials are characterized by TG/DSC, XRD and SEM. TG/DSC measurements show that the chemical reactions for the final product are completed below 400degreesC. XRD analysis indicates that spinel structure is formed at around 650degreesC. However, SEM images show well-defined polyhedron crystalline particles do not appear until 800degreesC. Electrochemical evaluation shows that LiMn1.4Ni0.4Cr0.2O4 prepared at 850degreesC boasts the best electrochemical performance with an initial discharge capacity of 128 mA h/g and a capacity retention of more than 90% after 230 cycles between 3.5 and 4.98 V (C) 2004 Elsevier B.V. All rights reserved.