High-Performance\nSnTe Thermoelectric Materials Enabled\nby the Synergy of Band Convergence and Phonon Scattering

SnTe, an environmentally friendly thermoelectric material,\nhas\ngarnered widespread scholarly interest owing to its lead-free nature;\nhowever, its intrinsic thermoelectric performance is constrained by\na relatively low Seebeck coefficient and an extremely high lattice\nthermal conductivity. In this investigation, we employ the alloying\nof Ge and AgSbTe<sub>2</sub> to enhance the <i>zT</i> value\nof SnTe. The study found that Ge, Ag, and Sb can effectively enhance\nthe Seebeck coefficient and power factor of SnTe by utilizing band\nconvergence. At the same time, a multitude of point defects induce\nphonon scattering, consequently decreasing the lattice thermal conductivity\nof SnTe. Collectively, these synergistic effects result in Sn<sub>0.75</sub>Ge<sub>0.25</sub>Te-15% AgSbTe<sub>2</sub> achieving its\nhighest <i>zT</i> value of 1.28 at 823 K, with an average <i>zT</i> value of 0.77 between 400 and 823 K. Such high <i>zT</i> values of the SnTe-based thermoelectric material provide\nthe potential for applications in high-performance solid-state thermoelectric\ndevices.