Robust Homogeneous Segmented Power Generator Driven by Sb₂Te₃-Based Thermoelectrics.

Abstract

Thermoelectric (TE) technology offers a promising solution for waste heat recovery, particularly in applications involving abundant low-grade heat (<650 K). However, for over half a century, TE power generators have predominantly relied on Bi₂Te₃ alloys with limited efficiencies below 7%. Herein, Cd and S are doped into Sb₂Te₃ to promote microstructural regulation characterized by dense twin boundaries and dislocations, resulting in a 45% reduction of lattice thermal conductivity at 300 K. Combined with the optimized density-of-states effective mass and expanded band gap, the Cd_0.04Sb_1.96Te_2.94S_0.06 sample attains a peak ZT of 1.1 at 650 K and an average ZT of 1.0 from 500 to 650 K, while exhibiting remarkable compressive and bending strengths of 197 and 56 MPa. Most importantly, a well-designed, homogeneous segmented TE power generator, constructed entirely from Bi-Sb-Te alloys, achieves a remarkable efficiency of 9.3% under a temperature gradient of 350 K, as certified by third-party validation. This work provides new insights into extending the operation temperature of Bi₂Te₃, demonstrating great potential for low-grade waste heat harvest.