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Description:

Heat in crystalline materials is transported by phonons from lattice vibrations, and lattice thermal conductivity critically determines thermoelectric performance. Different from conventional approach that reduce thermal conductivity via extrinsic additives sacrificing electrical transport, here, we demonstrate a notable advancement in the n-type Mg3Sb1.5Bi0.5 by modulating phonon dynamics through lattice softening and simultaneously suppressing the phonon mean free path in a more localized manner while remaining compositionally invariant. Originating from Mg vacancies and derivative defects, elevated internal strain degrades bonding rigidity and localize phonons at the lattice-constant level, yielding an ultra-low thermal conductivity of 0.3 W m⁻¹ K⁻¹, close to the theoretical minimum. This intrinsic strategy, combined with electron concentration optimization, yields a ZTmax of 2.06 and an extraordinary ZTave of 1.58, exceeding state-of-the-art n-type materials. Furthermore, a single-leg generator and two-pair module deliver conversion efficiencies of 12.5% (ΔT = 440 K) and 7.4% (ΔT = 300 K), respectively, highlighting exceptional potential for waste heat recovery.

Rights:

• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

Keyword: thermoelectric

Date published: 2025-11-24

Publisher: Springer Science and Business Media LLC

Journal:

• Nature Communications (ISSN: 20411723) vol. 16 issue. 1 10366

Funding:

• MEXT | Japan Science and Technology Agency JPMJMI19A1

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1038/s41467-025-65325-7

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Updated at: 2025-12-15 10:24:14 +0900

Published on MDR: 2025-12-18 19:08:19 +0900