Advances in MgSb thermoelectric materials and devices

Thermoelectric technology offers a green-viable and carbon-neutral solution for energy problems by directly converting waste heat to electricity. For years, Bi 2 Te 3 -based compounds have been the main choice materials for commercial thermoelectric devices. However, Bi 2 Te 3 comprises scarce and toxic tellurium (Te) elements, which might limit its large-scale application. Recently, Mg 3 Sb 2 compounds have drawn increasing attention as an alternative to Bi 2 Te 3 thermoelectrics due to their excellent thermoelectric performance. Enabled by effective strategies such as optimizing carrier concentration, introducing point defects, and manipulating carrier scattering mechanisms, Mg 3 Sb 2 compounds have realized an improved thermoelectric performance. In this review, optimizing strategies for both Mg 3 Sb 2 -based thermoelectric materials and devices are discussed. Moreover, the flexibility and plasticity of Bi-alloyed Mg 3 Sb 2 mainly stemming from the dense dislocations are outlined. The above strategies summarized here for enhancing Mg 3 Sb 2 thermoelectrics are believed to be applicable to many other thermoelectrics. Effective strategies such as manipulation of carrier scattering mechanism, introduction of phonon scattering sources, and optimization of interface layer for improving Mg 3 Sb 2 thermoelectric materials and devices are summarized.