Exploiting the fraternal twin nature of thermoelectrics and topological insulators in Zintl phases as a tool for engineering new efficient thermoelectric generators

Abstract

This review article presents a radical overview of the rich chemistry and physics of Zintl phases as it relates to their interesting structure-property relationships. In particular, it unveils the evolution...

Zintl Phases: From Curiosities to Impactful Materials

“…Thermoelectric materials can harvest energy by converting a temperature gradient into electricity. This unique ability has many applications in industry, including the use of Peltier coolers for refrigeration technology and waste heat recovery to generate power. , There have been several reviews of Zintl phases and thermoelectric applications; ,, therefore, in this Perspective, I will be brief on this last point. The generally accepted materials to explore for optimal thermoelectric applications are identified as semiconducting compounds with structural complexity that can be doped or substituted with isovalent or aliovalent atoms to increase or reduce the carrier concentration.…”

“…This contrasts with Laves phases, which are intermetallics with the AB 2 composition that crystallize in structure types such as Mg 2 Cu, Mg 2 Zn, and Mg 2 Ni, where the relative size of the elements and total electron count rather than chemical bonding considerations provide guiding principles . Care should always be taken when using any simple model, and electronic structure calculations provide a more detailed view of bonding. , The strength of the Zintl approach, connecting chemical and electronic structure using valence bonding principles, allows for the rational design of new compounds with important technological properties, such as magneto­electronics, − thermo­electricity, ,− and other energy storage and conversion capabilities. − Another area of research where Zintl phases are of great importance is in the synthesis of new materials that are difficult to prepare by bottom-up solution reaction processes . Metathesis reactions of binary or ternary Zintl phases with metal halides result in a variety of new materials.…”

“… 18 Care should always be taken when using any simple model, and electronic structure calculations provide a more detailed view of bonding. 18 , 19 The strength of the Zintl approach, connecting chemical and electronic structure using valence bonding principles, allows for the rational design of new compounds with important technological properties, such as magnetoelectronics, 20 − 22 thermoelectricity, 10 , 23 − 25 and other energy storage and conversion capabilities. 26 − 29 Another area of research where Zintl phases are of great importance is in the synthesis of new materials that are difficult to prepare by bottom-up solution reaction processes.…”

Crystal and electronic structure of the ternary Zintl bismuthide BaLiBi

“…[8] More recently, the peculiar band structures of Zintl phases, featuring narrow bandgaps or pseudogaps, have evoked renewed interest in this class of compounds as potential candidates for topological materials. [9] In an idealized chargebalanced Zintl phase, the valence and conduction bands are expected to be separated by a well-defined bandgap. In reality, the incomplete electron transfer between the cationic and anionic parts of a crystal structure may result in a gapless state where only a small number of bands cross or "touch" the Fermi level.…”

First Principle Investigations on Structural, Mechanical, Electronic, And Thermoelectric Properties of XCoP (XTi, Zr, Hf) Half Heusler Alloys for Energy Recovery Application

“…The best TE material is thought to have a high Seebeck coefficient, high electrical conductivity, and low thermal conductivity, where all three factors are reliant on one another. Till date, by considering the cost effectiveness, ease of material design and high figure of merit, different types of thermoelectric materials have been analyzed including Skutterudites, [4] Tetrahedrites, [5] Zintl Phases, [6] Clathrates, [7] Tellurides, [8] Sulphides, [9] Selenides, [10] Metal Chalcogenides, [11] Heusler Alloys (HA) etc. [12] The first principle calculations are very useful to discover highly efficient new thermoelectric materials.…”