Simultaneous enhancement of thermoelectric performance and mechanical properties in Bi₂Te₃ via Ru compositing

Recently, researchers have been exploring the optimization of the thermoelectric properties of composite materials. Composite technology with many successful cases of enhancement in thermoelectric properties have been confirming effectively to optimize thermoelectric materials. In this study, Ru nano-micro composite particles were successfully introduced in commercial bismuth telluride (Bi₂Te₃) as second phase to simultaneously optimize the thermoelectric and mechanical properties. In a Bi₂Te₃ sample containing 1 wt% Ru (+1 wt% Ru), the ZT peak was measured to be 0.93 (at 150 °C) and the maximum Vickers hardness was measured to be 2.38 GPa. These values exceeded the values of a pure sample by 45.3% and 36%, respectively. The average ZT of the +1 wt% Ru sample at 50–200 °C was 0.86, which is comparable with the Bi₂Te_3-xSe_x system. By varying the Ru content, the components, microstructure, thermoelectric and mechanical properties of Bi₂Te₃ were manipulated and their interdependence demonstrated. The extent to which the thermoelectric and mechanical properties of Bi₂Te₃ can be optimized, via Ru compositing and nano-Bi₂Te₃ producing, is related by the complex nano-micro composite structure. The superior thermoelectric properties of composite materials hold great the commercial value and may reduce the input of raw materials.