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 Bi0.48Sb1.52Te3-AgSbSe2 composites. It is found that the increased hole concentration improves the S2σ to 40 μW cm-1 K-2 at room temperature, and the emerged various defects effectively suppress the κl to 0.57 W m-1 K-1 at 350 K. All effects harvest a highest ZT = 1.2 at 350 K along with an average ZT = 1.0 between 300-500 K in the x = 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.
Keywords: AgSbSe2; bismuth telluride; hot pressing; mechanical performance; thermoelectric.