X-ray diffraction and 7Li nuclear magnetic resonance studies of iron- and cobalt-substituted LiNiO2 prepared from inorganic transition metal nitrates

LiNi1-xFexO2 (0.1less than or equal toxless than or equal to0.3) compounds were synthesized at variable temperatures via two different preparation procedures, the standard "solid state" method and the lower temperature synthesis method, the latter involving inorganic nitrate salt precursors. Long-range structure was characterized by X-ray diffraction (XRD), and Li-7 NMR measurements were performed to investigate the correlation between the synthesis routes and the local distribution of transition metal ions in the product. The results show that 700 degreesC is the optimum synthesis temperature and that the molten nitrate route requires lower firing temperature than the solid state method. The substitution of Fe tends to create distortion in the layered structure. Results for LiNi1-xCoxO2 are also presented. (C) 2004 Elsevier B.V. All rights reserved.