Enhanced Thermoelectric and Mechanical Performances in Sintered Bi_0.48Sb_1.52Te₃–AgSbSe₂ Composite

Abstract

Bismuth telluride alloys have dominated the industrial application of thermoelectric cooling, but the relatively poor mechanical performance of commercial zone-melting material seriously limits the device integration and stability. Here, we exhibit synergistically enhanced thermoelectric and mechanical performances of sintered Bi_0.48Sb_1.52Te₃-AgSbSe₂ composites. It is found that the increased hole concentration improves the <i>S</i>²σ to 40 μW cm^-1 K^-2 at room temperature, and the emerged various defects effectively suppress the <i>κ</i>_l to 0.57 W m^-1 K^-1 at 350 K. All effects harvest a highest <i>ZT</i> = 1.2 at 350 K along with an average <i>ZT</i> = 1.0 between 300-500 K in the <i>x</i> = 0.2 sample. Notably, AgSbSe₂ addition not only optimizes the thermoelectric properties, but also enhances the mechanical performance with a Vickers hardness of 0.75 GPa. Furthermore, the isotropy of thermoelectric properties is also observably promoted by solid-phase reaction combined with high-energy ball milling and hot pressing. Our study reveals a viable strategy to improve the comprehensive performance of sintered bismuth telluride materials.