Structural and electrochemical properties of LiNiyTi1-yO2 prepared by a wet process

LiNiyTi1-yO2 (0.7 less than or equal to v less than or equal to 0.95) solid solution has been prepared by a wet process. According to X-ray diffraction analysis, these materials are found to have a rhombohedral layered structure (R (3) over barm) and are an isostructure LNiO2. The I(104)/I(003) intensity ratio is increased with Ti concentration, which indicates the cation mixing between transition metal layer and lithium layer is occurred. The LiNiyTi1-yO2 compounds have well-developed layered structures and a particle size of similar to1 mum. The titanium and nickel in the lattice is found to be trivalent and bivalent, respectively. The first discharge capacity of LiNiyTi1-yO2 is 10-25 mAh g(-1). These values are inferior to those of LiNiyTi1-yO2 prepared by a solid-state reaction (30 mAh g(-1)). The low discharge capacities are due to local structural change during the first charge, where transition metal ions in the lithium layer block the diffusion of Li ions. (C) 2003 Published by Elsevier Science B.V.