Doping Element Effects on the Thermoelectric Output Performance of Metallized Mg2Si0.9Sn0.1 Synthesized by the Single-Step SPS Technique

Abstract

Stable, durable, and inexpensive thermoelectric power generators are desirable in waste heat recovery applications for effectively utilizing depleting fossil energy sources and protecting the environment by reducing greenhouse and toxic gas emissions. However, due to their low power conversion efficiency, usage of expensive materials, high production cost, complex contact selection, and fabrication strategy, the thermoelectric devices are not the best alternative in renewable energy sectors. The present study demonstrated the simultaneous fabrication of Mg₂(Si_0.9Sn_0.1)_0.95Bi_0.05 thermoelectric compound and contact electrode joint, eliminating the thermoelectric leg element’s manufacturing complexity. Further, the cross-section microstructural analysis of the synthesized thermoelectric element confirmed the thermoelectric materials’ phase purity and adequate interfacial joining materials’ diffusion chemistry. Also, the thermoelectric conversion efficiency evaluation system assessed the synthesized elements’ electrical properties by real-time temperature difference conditions (ΔT ≈ 30 to 480 K). The synthesized Mg₂(Si_0.9Sn_0.1)_0.95Bi_0.05 silicide material with contact electrode joining imparts low and stable contact resistance values from low to high temperatures in the measured temperature range.