Beyond Bismuth Telluride: Magnesium-Based Compounds Redefine Thermoelectric Excellence

Thermoelectric (TE) technology converts heat directly into electricity, and is a promising source of clean electricity. Commercial TE modules are based on Bi2Te3 compounds because of their unrivalled TE properties at low-grade heat-related temperatures (<550 K). However, the scarcity of elemental Te severely limits the applicability of these modules. Here, we present the performance of TE modules assembled from Te-free compounds, including p-type MgAgSb and n-type Mg3(Sb,Bi)2, using a simple, versatile and therefore scalable processing routine. We demonstrate module-level conversion efficiencies of 3% and 8.5% for temperature differences of 75 K and 260 K, respectively, as well as maximum cooling of 72 K when used as a cooler. These proofs of principle will pave the way for robust, high-performance and sustainable solid-state power generation and cooling to replace the highly rare and toxic Bi2Te3.