Synthesis and structural characteristics of LiCoO2 powders prepared by mechanical alloying of LiOH•H2O and Co(OH)2

From the hydroxides LiOH .H2O and Co(OH)(2) as starting materials, the precursor of a LiCoO2 cathode for lithium rechargeable batteries has been synthesized by mechanical alloying (MA). Highly crystallized HT-LiCoO2 was obtained by subsequent firing of the ball milled precursor at 600 degreesC for only 2 h in air, which were drastically improved firing conditions compared with the conventional solid state reaction using carbonates and oxides. The optimum ball milling conditions for mechanical alloying have been determined. The structural evolution of powders with various process variables and firing conditions was investigated by analysis of TG-DSC plots and XRD patterns. For faster reactions during the MA process and reduction of subsequent firing temperature and times, it is necessary to adjust the milling device for the removal of the byproduct of the dehydration, water, and the use of an O-2 atmosphere. However, as a new synthetic process of lithium-intercalation oxides as well as of LiCoO2, the effectiveness of mechanical alloying has been proved. (C) 2001 Elsevier Science B.V. All rights reserved.