Electrochemical properties of LiNi1-yFeyO2 synthesized by the combustion method in O2

LiNi1-yFeyO2 (0.000 <= y <= 0.025) with small y prepared by a combustion method have only the phase with the alpha-NaFeO2 structure of the rhombohedral system (space group; R (3) over barm). Fe is quite continuously detected over the analysis line of EPMA on the surface of LiNi0.995Fe0.005O2, indicating that Fe is distributed quite uniformly LiNi0.995Fe0.005O2 shows better electrochemical properties than LiNiO2 with the highest first. charge capacity (285 mAh/g) and the highest first discharge capacity (165 mAh/g) at 0.1C-rate among LiNi1-yFeyO2 (0.000 <= y <= 0.025). FTIR clesorbance curves indicate that Li2CO3 remains in LiNiO2. However, the peaks for Li2CO3 are very weak in the Fe-substituted samples. Electron diffraction pattern of LiNi0.995Fe0.005O2 exhibits four diffraction points coming from a local Fm3m structure made by cation mixing. A larger number of Li+ occupying the Li sites. due to the preferential occupation of Fe3+ in the Li sites, decrease the mixing of Ni2+ into the Li sites and improve the electrochemical properties of LiNiO2 (C) 2009 Elsevier B.V. All rights reserved.