Ultra-Low Heat Conductivity by Configurational Entropy for Thermoelectric Conversion

High-entropy oxides are promising candidates for thermoelectric energy conversion due to their separately tunable thermal and electrical conductivities. Here, we examine entropy-driven heat conductivity reduction in high-entropy wolframite (Ni,Co,Mn,Fe,Zn)WO₄. The Debye–Klemens–Callaway model, parameterized from first principles, is used to predict heat transport, extract phonon-interaction parameters, and quantify the influence of phonon scattering on thermal properties. This analysis highlights the pivotal role of mass disorder in enhancing phonon–defect scattering, which we identify as a primary mechanism in suppressing heat transport. Leveraging configurational entropy to control thermal conductivity thus provides a versatile framework for optimizing thermoelectric performance.