Improvement of the Thermoelectric Properties of p-Type Mg3Sb2 by Mg-Site Double Substitution

Juan Li; Kejia Liu; Xiaojing Ma; Zhongran Yang; Liqun Yi; Jun Mao; Qian Zhang

doi:10.1021/acs.inorgchem.4c00522

Improvement of the Thermoelectric Properties of p-Type Mg₃Sb₂ by Mg-Site Double Substitution

Inorg Chem. 2024 Apr 30. doi: 10.1021/acs.inorgchem.4c00522. Online ahead of print.

Authors

Juan Li¹, Kejia Liu¹, Xiaojing Ma¹, Zhongran Yang¹, Liqun Yi¹, Jun Mao^{1

2}, Qian Zhang^{1

2}

Affiliations

¹ School of Materials Science and Engineering and Institute of Materials Genome & Big Data, Harbin Institute of Technology, Shenzhen 518055, China.
² State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China.

PMID: 38687967
DOI: 10.1021/acs.inorgchem.4c00522

Abstract

A P-type Mg₃Sb₂-based Zintl phase compound has been considered a promising candidate for thermoelectric applications. Alloying, which introduces a high concentration of point defects, is particularly effective in scattering phonons and reducing lattice thermal conductivity. Herein, alloying in p-type Mg_2.995Na_0.005Sb₂ via the introduction of elements like Yb, Eu, Ca, and Ba was realized, and the room-temperature lattice thermal conductivity has been effectively reduced to ∼1.1 W m^-1 K^-1. To further intensify the phonon scattering, two groups of elements (Eu and Cd, and Yb and Cd) were chosen for heavy alloying at the Mg site, and the lattice thermal conductivity of Mg_1.49Eu_0.5Cd₁Na_0.01Sb₂ was further reduced to ∼0.45 W m^-1 K^-1. Eventually, a peak zT as high as ∼1.0 was achieved at 773 K, and the compound outperforms the previously reported p-type Mg₃Sb₂ compounds.