Rapid One‐Step Synthesis and Compaction of High‐Performance n‐Type Mg₃Sb₂ Thermoelectrics

Abstract

n‐type Mg3Sb2‐based compounds have emerged as a promising class of low‐cost thermoelectric materials due to their extraordinary performance at low and intermediate temperatures. However, so far, high thermoelectric performance has merely been reported in n‐type Mg3Sb2‐Mg3Bi2 alloys with a large amount of Bi. Moreover, current synthesis methods of n‐type Mg3Sb2 bulk thermoelectrics involve multi‐step processes that are time‐ and energy‐consuming. Herein, we report a fast and straightforward approach to fabricate n‐type Mg3Sb2 thermoelectrics using spark plasma sintering, which combines the synthesis and compaction in one step. Using this method, we achieve a high thermoelectric figure of merit zT of about 0.4–1.5 at 300–725 K in n‐type (Sc, Te)‐co‐doped Mg3Sb2 without alloying with Mg3Bi2. In comparison with the currently reported synthesis methods, the complexity, process time, and cost of our method are significantly reduced. This work demonstrates a simple, low‐cost route for the potential large‐scale production of n‐type Mg3Sb2 thermoelectrics.