In‐situ Synchrotron X‐ray Diffraction Study of the Formation of Cubic Li2TiO3 Under Hydrothermal Conditions

Abstract Synchrotron powder X‐ray diffraction (PXRD) has been used to study in‐situ the hydrothermal intercalation of lithium ions in titania powder following the reaction TiO 2 + 2 LiOH → Li 2 TiO 3 + H 2 O. Syntheses were performed in a sapphire capillary at temperatures between 133 and 230 °C. By sequential Rietveld refinement of the PXRD data, the particle growth of the metastable cubic α‐Li 2 TiO 3 compound was determined as a function of the reaction time, as well as the transformation of the cubic α‐phase to its stable monoclinic β‐modifications at a temperature above the critical point of water. The reactions were presumed to be controlled by nucleation and crystal growth, and therefore the Avrami‐Erofe'ef equation was applied to model the reaction mechanisms of this intercalation process and an activation energy of 66(7) kJ/mol was determined.