High-performance Mg2SiSn-based thermoelectrics with superior compression strength and elastic resilience

The growing demand for sustainable energy solutions has intensified interest in thermoelectric materials capable of efficiently converting heat into electricity while maintaining robust mechanical performance. Here, we investigate Mg 2 Si 1- x Sn x -based thermoelectrics that combine superior compressive strength, high elastic limits, and cost-effectiveness compared with conventional Mg-based systems. These materials retain structural integrity under high compressive loads, ensuring stable operation in device applications. Additionally, the high elastic limits enable Mg 2 Si 1- x Sn x to recover the original dimension within the elastic region. To enhance performance, indium and antimony co-doping was employed to suppress lattice thermal conductivity and optimize carrier concentration simultaneously. As a result, Mg 2.13 In 0.02 (Si 0.3 Sn 0.7 ) 0.98 Sb 0.02 achieved a peak zT of ∼1.7 at 700 K, and a two-pair module with p -type MgAg 0.97 Sb 0.99 delivered a thermoelectric efficiency of ∼7.3% at a temperature difference of 300 K. Importantly, these modules are free of toxic elements. The demonstrated balance of mechanical robustness, high conversion efficiency, and sustainability positions Mg 2 Si 1- x Sn x as a promising n -type candidate for near-room to mid-temperature energy-conversion applications, particularly in scenarios requiring durable, mechanically resilient thermoelectric devices.