Synthesis and characterization of LiAlyCo1-yO2 and LiAlyNi1-yO2

Aluminum is of interest as a constituent in Li secondary battery cathodes d ue to its low cost and low mass. Increased intercalation potential for cert ain Al-doped intercalation oxides has also been predicted by ab initio calc ulations. We have synthesized single phase LiAlyCo1-yO2 and LiAlyNi1-yO2 so lid solutions from homogeneous hydroxide precursors. In LiAlyNi1-yO2, it wa s found that the addition of LiAlO2 helps to stabilize LiNiO2 in the alpha- NaFeO2 structure during air firing, facilitating preparation of the ordered phase. A systematic increase in the open circuit voltage is observed with Al content in both LiAlyCo1-yO2 and LiAlyNi1-yO2 solid solution, providing additional support for the ab initio calculations. (C) 1999 Elsevier Scienc e S.A. All rights reserved.