title: Discovery of high-performance low-cost n-type Mg3Sb2-based thermoelectric materials with multi-valley conduction bands.
abstract: Widespread application of thermoelectric devices for waste heat recovery requires low-cost high-performance materials. The currently available n-type thermoelectric materials are limited either by their low efficiencies or by being based on expensive, scarce or toxic elements. Here we report a low-cost n-type material, Te-doped Mg3Sb1.5Bi0.5, that exhibits a very high figure of merit zT ranging from 0.56 to 1.65 at 300-725 K. Using combined theoretical prediction and experimental validation, we show that the high thermoelectric performance originates from the significantly enhanced power factor because of the multi-valley band behaviour dominated by a unique near-edge conduction band with a sixfold valley degeneracy. This makes Te-doped Mg3Sb1.5Bi0.5a promising candidate for the low- and intermediate-temperature thermoelectric applications.
authors.affiliation: Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus, Denmark.
authors.forename: Jiawei
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus, Denmark.
authors.forename: Lirong
authors.initials: L
authors.lastname: Song
authors.affiliation: Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus, Denmark.
authors.forename: Steffen Hindborg
authors.initials: SH
authors.lastname: Pedersen
authors.affiliation: Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus, Denmark.|TEGnology ApS, Lundagervej 102, DK-8722 Hedensted, Denmark.
authors.forename: Hao
authors.initials: H
authors.lastname: Yin
authors.affiliation: Department of Energy Conversion and Storage, Technical University of Denmark, 399 Frederiksborgvej, 4000 Roskilde, Denmark.
authors.forename: Le Thanh
authors.initials: LT
authors.lastname: Hung
authors.affiliation: Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus, Denmark.
authors.forename: Bo Brummerstedt
authors.initials: BB
authors.lastname: Iversen