Thermoelectric performance enhancement of Mg₂Si-based silicides synthesized in nitrogen atmosphere

Abstract In this work, we compare the thermoelectric performance of Mg 2 Si-based compounds by synthesizing them in N 2 compared to Ar atmosphere during ball milling. In addition, we achieved high thermoelectric performance by introducing Sn-alloying as well as Zn- and Bi-co doping. The high performance originated from simultaneous improvement in electrical conductivity and reduced thermal conductivity. This results in peak zT near 1.0 at 760 K for Mg 1.9925 Zn 0.0075 Si 0.48 Sn 0.5 Bi 0.02 . Owing to the much lower cost (higher abundance) of N 2 compared to Ar owing to their much higher relative abundance, such processing strategy is expected to improve sustainability. Furthermore, the insights derived from this work can potentially be applied to other compounds containing Mg- and other reactive elements. Fundamentally, this result will also motivate further studies on the intrinsic defect formation in N 2 vs Ar atmosphere, which affects both electronic and thermal transports.