Enhanced Thermoelectric Performance of Indium-Doped n-type Mg3Sb2-Based Materials Synthesized by Rapid Induction Melting

n-type Mg3Sb2-based material is a promising thermoelectric material with less toxicity and more abundance. Herein, we successfully synthesized n-type polycrystalline Mg3.5-xInxSb1.7Bi0.26Te0.04(x = 0, 0.01, 0.02, 0.03, 0.04) samples by rapid induction melting and hot pressing. The effect of indium doping on the thermoelectric properties of Mg3Sb2-based materials was investigated. Indium doping manipulates the grain boundary scattering, resulting in increased electrical conductivity and carrier mobility. Additionally, the lattice disorder induced by In strengthens the phonon scattering and suppresses lattice thermal conductivity. A peak ZT value of 1.27 is obtained at 773 K in the Mg3.47In0.03Sb1.7Bi0.26Te0.04 sample, which is 26% higher than that of the In-free sample. Our work indicates that indium is an alternative metal addition to improve mobility and thermoelectric performance.

Automated summary

In this study, indium-doped samples of n-type Mg3Sb2-based materials were successfully synthesized. It was found that indium doping can increase the electrical conductivity and carrier mobility of the materials, while suppressing the lattice thermal conductivity. A higher ZT value was achieved in the Mg3.47In0.03Sb1.7Bi0.26Te0.04 sample.