Advances in Mg3Sb2 thermoelectric materials and devices

Abstract

Thermoelectric technology offers a green-viable and carbon-neutral solution for energy problems by directly converting waste heat to electricity. For years, Bi2Te3-based compounds have been the main choice materials for commercial thermoelectric devices. However, Bi2Te3 comprises scarce and toxic tellurium (Te) elements, which might limit its large-scale application. Recently, Mg3Sb2 compounds have drawn increasing attention as an alternative to Bi2Te3 thermoelectrics due to their excellent thermoelectric performance. Enabled by effective strategies such as optimizing carrier concentration, introducing point defects, and manipulating carrier scattering mechanisms, Mg3Sb2 compounds have realized an improved thermoelectric performance. In this review, optimizing strategies for both Mg3Sb2-based thermoelectric materials and devices are discussed. Moreover, the flexibility and plasticity of Bi-alloyed Mg3Sb2 mainly stemming from the dense dislocations are outlined. The above strategies summarized here for enhancing Mg3Sb2 thermoelectrics are believed to be applicable to many other thermoelectrics.