Thermoelectric and thermomechanical properties of the hot pressed polycrystalline Bi0.5Sb1.5Te3 alloys

The polycrystalline pseudo-binary Bi0.5Sb1.5Te3 alloys have been prepared by hot pressing. X-ray diffraction analysis indicated that there is no noticeable preferred orientation in all the samples. Thermoelectric properties were measured and a relatively high ZT value of ∼0.9 was obtained at room temperature. Thermal mechanical properties were characterized by dilatometer and dynamic-mechanical thermal analyzer. The thermodynamic stability of these alloys could be kept from room temperature to 500 K. It is suggested that Bi0.5Sb1.5Te3 alloys are suitable for the applications below 500 K.

Research highlights▶ Bismuth telluride and its alloys are the most effective thermoelectric materials at room temperature. Recently most of the researches on Bi2Te3 alloys are focused on polycrystalline bulk materials which exhibiting both well improved thermoelectric and mechanical properties. However, to our knowledge, there are few reports on the temperature dependence of mechanical properties. In this manuscript, polycrystalline pseudo-binary Bi0.5Sb1.5Te3 alloys have been prepared by hot pressing. Thermoelectric properties have been measured and a relatively high ZT value of ∼0.9 has been obtained at room temperature. The temperature dependence of thermal mechanical properties and thermal stabilities have also been investigated, and the results indicated that Bi0.5Sb1.5Te3 alloys are only appropriate for application from room temperature up to 500 K. Finally, this work may provide much more information for improving the reliability of TE modules.