Entropy and heterogeneous interface engineering promote the low thermal conductivity in SnTe-based thermoelectric materials

High thermal conductivity seriously hinders the application and development of eco-friendly SnTe thermoelectric material. Here, entropy and heterogeneous interface were designed to reduce the thermal conductivity of SnTe thermoelectric material. SnTe and Sn 0.7- x Mn x Pb 0.3 Te 0.7 Se 0.3 ( x = 0, 0.06, 0.09) samples were synthesized via vacuum melting reaction and spark plasma sintering. Pb and Se were introduced into the SnTe, which results in valence band convergence according to density functional theory calculations. To further improve the thermoelectric performance, the Mn elements were also introduced into above system, and the lowest lattice thermal conductivity achieved 0.48 W m −1 K −1 at 773 K via the phonon scattering of the configurational entropy and the heterogeneous interface of MnSe precipitates for Sn 0.61 Mn 0.09 Pb 0.3 Te 0.7 Se 0.3 sample. The maximum ZT value of 0.85 at 773 K accompanied by the ultralow lattice thermal conductivity in Sn 0.61 Mn 0.09 Pb 0.3 Te 0.7 Se 0.3 sample, which increased by ~ 113% than SnTe. The chaotic entropy engineering could be an efficient way to decrease the lattice thermal conductivity, and the strategy can be extended to thermoelectric materials, thermal barrier materials, thermal insulation materials fields, etc.