Modulating phonon dynamics: tailoring lattice vibrations to enhance thermoelectric efficiency in Mg<sub>3</sub>(Sb, Bi)<sub>2</sub> alloy.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41285761.
- Also identified by DOI 10.1038/s41467-025-65325-7 and PMC identifier 12644559.
- Licence recorded as CC BY-NC-ND.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
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 Mg<sub>3</sub>Sb<sub>1.5</sub>Bi<sub>0.5</sub> 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 ZT<sub>max</sub> of 2.06 and an extraordinary ZT<sub>ave</sub> 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.