LiCo0.8Ni0.1Mn0.1O2 positive electrode material was prepared via the combustion method followed by a thermal treatment at 900 degrees C for 1 h. A systematic study has been performed to investigate the structural changes of LiCo0.8Ni0.1Mn0.1O2 upon chemical lithium extraction. X-ray diffraction (XRD), electronic paramagnetic resonance (EPR), and magnetic susceptibility measurements were performed. These experiments provided a detailed picture of the whole delithiation process. Not only oxidation of Ni2+ ions but also some Co3+ ions were evidenced at the beginning of the delithiation process. Further lithium extraction induces an insulator to metal transition for the composition Li0.3Co0.8Ni0.1Mn0.1O2 as shown by the plot of chi(-1) (T) vs. T, which is similar to that reported for LiyCoO(2). The electrochemical performances of the LiCo0.8Ni0.1Mn0.1O2 sample were measured at different current rates in the 3-4.5 V potential range. This material exhibits good discharge capacity of 180 mAh g(-1) and a columbic efficiency approaching 96%. (C) 2016 Elsevier B.V. All rights reserved.