Ding, Jinxue ; Li, Wei ; Thiem, Moritz ; Skokov, Konstantin P. ; Kintop, Nina ; Weidenkaff, Anke ; Xie, Wenjie (2025)
Achieving low thermal conductivity and high quality factor in sextuple-doped TiS2.
In: Acta Materialia, 283
doi: 10.1016/j.actamat.2024.120548
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

Transition-metal dichalcogenide TiS2 stands out as a sustainable candidate for room- and medium-temperature thermoelectric materials due to its affordability, non-toxicity, eco-friendly nature and use of non-critical elements. However, its light element compositional nature results in a large thermal conductivity, which is the main limitation of the thermoelectric performance of TiS2. Here, we report a multi-element doping strategy by incorporating equivalent (Se, Zr) elements and introducing higher-valence (Nb, Ta) and lower-valence (Y, La) elements in pairs to minimize its lattice thermal conductivity, kappa lat. The findings indicate a nearly 50 % decrease in kappa lat across the entire temperature range, attributed to the presence of strong point-defect scattering after multielement doping. Additionally, we observed a reduced dependency of kappa lat on temperature in multi-element doped TiS2, as point defects can effectively scatter phonons at room temperature. As a result, the multi-element doped TiS2 attained its highest ZT value of approximately 0.4 at 625 K. Incorporating higher-valence and lower-valence elements in pairs proves to be an effective method for decreasing lattice thermal conductivity without compromising too much of its large Seebeck coefficient.

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