Kinetics of reactions in interlayer space of titanium diselenide intercalated with iron

Abstract

Decomposition of a homogeneous intercalation compound with the formation of inclusions in the interlayer space of a matrix lattice has been directly observed. In full compliance with previously advanced theoretical concepts, it has been shown that the decomposition is accompanied by metallic iron extraction, which then gradually transforms into iron selenide due to the interaction with gaseous selenium.The hierarchy of diffusion mobilities of various defects in Fe_xTiSe₂ intercalation compound has been determined. It has been found that the largest mobility is inherent to intrinsic defects of the TiSe₂ lattice, i.e., vacancies in Ti and Se sublattices. The phenomenon of dissociation pressure oscillations as a function of time has been detected. This phenomenon has been explained by the existence of a slow decomposition stage, i.e., intercalated iron diffusion during the formation and dissolution of its inclusions as an individual phase.