A Novel Electronegative Guest-Filled Skutterudite-Based Thermoelectric Generator with an Efficiency of 6.0%

Electronegative guest-filled skutterudites (EN-SKDs) are considered one of the most promising thermoelectric materials for next-generation thermoelectric generators (TEGs). However, the practical application of EN-SKDs in TEGs is still a huge challenge because of their unsatisfactory zT value (less than 1.0). Herein, Ge, Te-codoped electronegative sulfur-filled skutterudites of S_xCo₄Sb₁₁Ge_0.2Te_0.8 (x = 0, 0.05, 0.1, 0.2, 0.25) are synthesized. The optimal zT value of as high as 1.45 at 823 K with a low room-temperature lattice thermal conductivity of 1.98 W m⁻¹ K⁻¹ is achieved by S_0.25Co₄Sb₁₁Ge_0.2Te_0.8. Such performance is competitive with those of traditional TE materials and among one of the best EN-SKDs. The excellence is attributed to the synergistic effect of the disorder caused by Ge, Te co-doping at Sb-site and the “rattling” effect of electronegative element S. Furthermore, a novel EN-SKD-based TEG is prepared for the first time through an integrated welding process and exhibits a high efficiency of 6.0% at the temperature difference of 475 K. This work provides valuable guidance for designing advanced thermoelectric materials and paves a way toward high-performance EN-SKD-based TEGs.