Reaction mechanism and kinetics analysis of lithium nickel oxide during solid-state reaction

The reaction mechanism and kinetics analysis for the formation of lithium nickel oxide (LiNiO2) during solid-state reaction have been investigated. The atmosphere during the reaction has a pronounced effect on the stoichiometry and cation arrangement of LiNiO2. It is obligatory to supply adequate oxygen partial pressure to overcome the diffusion barrier existent in the precursor powder. It is difficult to synthesize stoichiometric LiNiO2 with the R (3) over bar m structure if the oxygen partial pressure is too low. The formation of LiNiO2 requires continuous heat treatment for a certain period of time which depends on the heating temperature and the oxygen partial pressure provided. Based on the Johnson-Mehl-Avrami equation, LiNiO2 formation is governed by a three-dimensional diffusion controlled mechanism. The reaction kinetics of LiNiO2 formation are satisfactorily expressed by the Brounshtein-Ginstling model, and the activation energy of the formation process is estimated to be 76.1 kJ mol(-1). A microscopic reaction model for the formation of LiNiO2 has been established.