High-Performance SnTe Thermoelectric Materials Enabled by the Synergy of Band Convergence and Phonon Scattering.

SnTe, an environmentally friendly thermoelectric material, has garnered widespread scholarly interest owing to its lead-free nature; however, its intrinsic thermoelectric performance is constrained by a relatively low Seebeck coefficient and an extremely high lattice thermal conductivity. In this investigation, we employ the alloying of Ge and AgSbTe to enhance the value of SnTe. The study found that Ge, Ag, and Sb can effectively enhance the Seebeck coefficient and power factor of SnTe by utilizing band convergence. At the same time, a multitude of point defects induce phonon scattering, consequently decreasing the lattice thermal conductivity of SnTe. Collectively, these synergistic effects result in SnGeTe-15% AgSbTe achieving its highest value of 1.28 at 823 K, with an average value of 0.77 between 400 and 823 K. Such high values of the SnTe-based thermoelectric material provide the potential for applications in high-performance solid-state thermoelectric devices.