Ultra‐Low‐Cost Sulfide‐Dominant Thermoelectric Power Generation Module with Enhanced Hardness

Continuous exploration of electron‐phonon transport decoupling mechanisms and advances in device fabrication have led to record‐high power conversion efficiency ( η ) of PbTe, GeTe and Bi 2 Te 3 based thermoelectric (TE) materials, yet their application is hampered by tellurium scarcity and high costs. Herein, we report a low‐cost, high‐efficiency, and mechanically strengthened sulfide‐based thermoelectric system based on Sb‐doped n‐type PbS with PbTe incorporation. It achieves a high zT of 1.2 at 823 K and ultrahigh mechanical strength. Further, the PbS barrier layer was deliberately screened via a three‐step screening strategy of thermal expansion coefficient, work function difference and melting point, to construct an economic screening design framework for lead sulfide thermoelectric materials. The enhanced mechanical strength induced by the grain refinement and enhanced bonding strength after Sb doping, as well as the interface dislocations generated by PbTe incorporation, provide a solid foundation for the fabrication of sulfur‐based devices. The n‐type PbS single‐leg devices and sulfide‐dominant n‐PbS/p‐Cu 1.96 S multi‐leg devices achieved conversion efficiencies of 2.0% and 2.6% under a Δ T of 400 K, respectively.