Abstract

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 Rm 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.