Improved figure of merit (z) at low temperatures for superior thermoelectric cooling in Mg<sub>3</sub>(Bi,Sb)<sub>2</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37582957.
- Also identified by DOI 10.1038/s41467-023-40648-5 and PMC identifier 10427716.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The low-temperature thermoelectric performance of Bi-rich n-type Mg<sub>3</sub>(Bi,Sb)<sub>2</sub> was limited by the electron transport scattering at grain boundaries, while removing grain boundaries and bulk crystal growth of Mg-based Zintl phases are challenging due to the volatilities of elemental reactants and their severe corrosions to crucibles at elevated temperatures. Herein, for the first time, we reported a facile growth of coarse-grained Mg<sub>3</sub>Bi<sub>2-x</sub>Sb<sub>x</sub> crystals with an average grain size of ~800 μm, leading to a high carrier mobility of 210 cm<sup>2</sup> · V<sup>-1</sup> · s<sup>-1</sup> and a high z of 2.9 × 10<sup>-3 </sup>K<sup>-1</sup> at 300 K. A [Formula: see text]T of 68 K at T<sub>h</sub> of 300 K, and a power generation efficiency of 5.8% below 450 K have been demonstrated for Mg<sub>3</sub>Bi<sub>1.5</sub>Sb<sub>0.5</sub>- and Mg<sub>3</sub>Bi<sub>1.25</sub>Sb<sub>0.75</sub>-based thermoelectric modules, respectively, which represent the cutting-edge advances in the near-room temperature thermoelectrics. In addition, the developed grain growth approach can be potentially extended to broad Zintl phases and other Mg-based alloys and compounds.