Fast fabrication of SnTe via a non-equilibrium method and enhanced thermoelectric properties by medium-entropy engineering

Abstract

Single-phase SnTe-based thermoelectric materials were prepared by a fast preparation method, known as self-propagating high-temperature synthesis under high-gravity field combined with spark plasma sintering (SHS-HG-SPS), which shortens the synthesis time from several days to several minutes. Entropy engineering has been reported as an effective method to tune the delicate trade-off between the electrical transport properties and lattice thermal conductivity, resulting in an improvement of the thermoelectric performance. Herein, the (Ge, Pb, Sb, Mn) co-alloyed SnTe alloys with medium-entropy are reported. An ultralow lattice thermal conductivity of ∼0.30 W m⁻¹ K⁻¹ and a higher zT value of ∼1.1 are obtained for (Sn_0.70Ge_0.15Pb_0.15)_0.86Sb_0.04Mn_0.1Te at 873 K. This work demonstrates that medium-entropy engineering is an effective strategy to obtain high thermoelectric properties for SnTe-based materials.