Charting lattice thermal conductivity for inorganic crystals and discovering rare earth chalcogenides for thermoelectrics

Abstract

Thermoelectric power generation represents a promising approach to utilize waste heat. The most effective thermoelectric materials exhibit low thermal conductivity k. However, less than 5% out of about 10 synthesized inorganic materials are documented with their k values, while for the remaining 95% k values are missing and challenging to predict. In this work, by combining graph neural networks and random forest approaches, we predict the thermal conductivity of all known inorganic materials in the Inorganic Crystal Structure Database, and chart the structural chemistry of k into extended van-Arkel triangles. Together with the newly developed k map and our theoretical tool, we identify rare-earth chalcogenides as promising candidates, of which we measured ZT exceeding 1.0. We note that the k chart can be further explored, and our computational and analytical tools are applicable generally for materials informatics.