Thermodynamics and Related Kinetics of Staging in Intercalation Compounds

Staging phenomena occur in a wide range of materials. In this work, we investigate the thermodynamic properties of multilayer free-energy models, which includes both intralayer and interlayer interactions. We show that a continuous screening effect for the repulsive interaction between layers is necessary to predict the occurrence of staged phases, without the nonphysical nonpure ones. Included in a phase-field formulation, this high-order free-energy model allows to simulate for the first time the complex staging kinetics between stage 3 and stage 2, without the occurrence of the nonpure 3/2 phase, including island migration dynamics of the Daumas & Herold model.