Jang, Kyuseon Dey, Poulumi Dutta, Biswanath Park, Hail Son, Ji-Hee Jang, Jeong-In Bhat, Mohammed Kamran Jang, Hanhwi Kim, Hyungsub Choi, Jungwoo Zhang, Siyuan Villoro, Ruben Bueno Berkels, Benjamin Kim, Bongseo Choi, Pyuck-Pa Oh, Min-Wook Jung, Yeon Sik Han, Jeong Woo Scheu, Christina Jung, Chanwon 2025-07-18T09:00:49Z 2025-07-18T09:00:49Z 2025-07-18 2025-08 1385-8947 https://pubs.kist.re.kr/handle/201004/152818 The high thermal stability of a thermoelectric material, which maintains a stable conversion efficiency under prolonged heat exposure, is essential for sustainable thermoelectric applications. Despite the well-known relationship between thermal degradation and microstructural evolution, their underlying interplay remains unclear, with contradictory findings reported in the literature owing to the complex dependence of microstructural changes on the material composition. Herein, the effect of Sb doping on the thermal stability of NbCoSn halfHeusler compounds is investigated in detail by comprehensively analyzing their microstructural evolution. The results reveal that introducing 3.3 at.% Sb into NbCoSn markedly enhances the thermal stability, by preserving the lattice thermal conductivity after heat exposure. Advanced techniques, including atom probe tomography, scanning transmission electron microscopy, and neutron diffraction, show that this improvement is driven by the evolution of Sb-induced complementary point defects. Although heat exposure significantly reduces lattice disorder in intrinsic NbCoSn, NbCoSn0.9Sb0.1 retains its lattice disorder by forming alternative point defects, thereby maintaining its lattice thermal conductivity. This detailed experimental work, corroborated by ab initio calculations, highlights the pivotal role of the point defect dynamics in achieving robust thermoelectric performances in half-Heusler compounds for high-temperature applications. English Elsevier BV Improved thermal stability of NbCoSn half-Heusler compounds via Sb doping-induced complementary point defect evolution Article 10.1016/j.cej.2025.164845 1 Chemical Engineering Journal, v.518 Chemical Engineering Journal 518 N scie scopus 001513881700021 Engineering, Environmental Engineering, Chemical Engineering Article THERMOELECTRIC PERFORMANCE CONDUCTIVITY Thermoelectric Point defect Atom probe tomography Transmission electron microscopy Neutron diffraction Thermal stability Half-Heusler