Flux synthesis and thermoelectric properties of eco-friendly Sb doped Mg2Si0.5Sn0.5 solid solutions for energy harvesting

Abstract

Mg₂Si_0.5−xSn_0.5Sb_x(x = 0–0.023) thermoelectric solid solutions have been successfully synthesized by a facile and cost-effective B₂O₃ flux method in air. X-ray diffraction analysis and scanning electron microscopy observations confirm that the single-phased Mg₂Si_0.5−xSn_0.5Sb_x compounds have been obtained. The peak power factor of the samples reached 3.2 × 10⁻³ W m⁻¹K⁻² at 610 K for x = 0.017. The maximum ZT values of >0.9 were reproducibly obtained at 780 K for x = 0.013, which are quite comparable with those of the state-of-the-art PbTe based thermoelectric alloys operated in the intermediate temperature range. The B₂O₃ flux method was also demonstrated to be effective for the batch production of Mg₂(Si,Sn) solid solutions.