Improving Stability of High‐Performance AgSbTe 2 Thermoelectrics by Lattice Regulation

ABSTRACT P‐type AgSbTe 2 has been proven as a promising alternative to high‐performance group IV–VI thermoelectric materials, however, its practical application is hindered by thermodynamic instability. It is shown an increase in cation to anion radius ratio helps stabilize the cubic structure among group IV–VI thermoelectrics. In this study, a substitution of Sb by larger Pb is therefore designed to improve the stability of AgSbTe 2 thermoelectrics. The effects of aliovalent Pb substitution on phase stability and thermoelectric transport properties were systematically investigated. The strategy not only significantly suppresses the precipitation of the Ag 2 Te secondary phase, but also effectively optimized the carrier concentration. As a result, AgSb 0.97 Pb 0.03 Te 2 achieves a zT value of 1.7 at 650 K. Thermoelectric devices fabricated using this material exhibit a highly reproducible power generation efficiency over 10% under a temperature gradient of ≈350 K. This study illustrates a lattice regulation approach to enhance both the thermal stability and thermoelectric performance of AgSbTe 2 thermoelectrics.