Ultralow Lattice Thermal Conductivity in SnTe by Incorporating InSb

Herein, a series of (Sn1.06Te)1–x-(InSb)x (x = 0, 0.025, 0.05, 0.075) samples are fabricated, and their thermoelectric performances are studied. The all-scale structure defects containing the atomic-scale In doping defects, the nanoscale Sb precipitates, and the mesoscale grain boundary scatter phonons collectively in a wide range of frequencies to give the ultralow lattice thermal conductivity. Concurrently, the incorporation of InSb decreases carrier concentration with marginal loss in carrier mobility, resulting in a little variation of electrical properties over a wide temperature range. The significantly decreased thermal conductivity and the preserved high power factor lead to a maximum ZT value of ∼0.84 at 823 K in the (Sn1.06Te)0.95(InSb)0.05 sample. This strategy of rapidly constructing all-scale structure defects could be applied to other thermoelectric systems to enhance thermoelectric performance.