Investigation of the structure-property relationship in compounds is crucial for materials design and discovery. A significant portion of the research efforts in solid state chemistry is focused on discovery of new materials to realize their critical properties for applications in energy storage and conversion. However, material synthesis is oftentimes challenging owing to the poor kinetics and diffusion barriers of solid-state reactions. Therefore, unconventional synthesis methods are used to overcome the synthetic difficulties posed by the traditional routes. One such synthetic methods is the hydride route. In the hydride route, a soft alkali metal is replaced with salt-like reactive alkali metal hydride. The use of hydride allows for precise compositional control and intimate mixing of precursors via ball milling. The latter leads to faster reaction times at much lower temperatures compared to the traditional solid-state synthetic routes. Therefore, the hydride route can be used for rapid phase exploration across several underexplored systems. Moreover, it allows for the synthesis of ternary phases composed of elements with significantly different reactivities. In my research project, the hydride route was employed for phase exploration in the K-V-Sb system, leading to the discovery of a novel ternary phase with tentative composition of KXV2Sb2. The structure of the KXV2Sb2 compound belongs to the monoclinic crystal system and represents a new structure type. The layered structure is composed of K layers sandwiched between layers of V and Sb and is closely related to the structure of V3Sb2. Decent quality single crystals for the ternary phase could not be grown despite several attempts. Hence, the structure was solved from high-resolution synchrotron powder X-Ray diffraction (PXRD) data. Differential Scanning Calorimetry (DSC) coupled with high-temperature in-situ synchrotron PXRD data show that the new phase is thermally stable up to 900 °C in vacuum. Crystal structure, magnetic and thermoelectric properties of the compound will be discussed. Overall, the hydride route was successfully utilized for the discovery of a novel KXV2Sb2 phase. Thorough structural analysis and detailed property investigation of the phase are ongoing to better understand and completely unlock the potential of this novel KXV2Sb2 phase.

Novel phase in the K-V-Sb system: Synthesis, crystal structure and properties

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.