Suppression of bipolar transport and enhanced zT values of porous ZnSb by addition of hydrothermally synthesized Sb.

ZnSb is a favourable eco-friendly, earth abundant SIand low cost thermoelectric material. We herein report a feasible approach to improve the thermoelectric performance of ZnSb by compositing with hydrothermally synthesized Sb. A series of ZnSb/Sb composites was fabricated by mixing the host material ZnSb and hydrothermally synthesized Sb followed by consolidation using cold pressing and evacuating-and-encapsulating sintering at 530 °C for 3 h. As compared to the host ZnSb, both the electrical resistivity and thermopower decrease, while both the power factor and thermal conductivity increase upon compositing with Sb. The bipolar transport of ZnSb is suppressed at temperatures up to 600 K. As a result, the ZnSb-Sb composite with 4 wt.% of hydrothermally synthesized Sb has a zT = 1.18 at 600 K, which is one of the highest values for ZnSb-based material and is about 46% enhancement as compared to the host ZnSb having zT = 0.81 at 600 K. [ABSTRACT FROM AUTHOR]