Approaching crystal's limit of thermoelectrics by nano-sintering-aid at grain boundaries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39097581.
- Also identified by DOI 10.1038/s41467-024-50946-1 and PMC identifier 11297969.
- Licence recorded as CC BY-NC-ND.
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Abstract
Grain boundary plays a vital role in thermoelectric transports, leading to distinct properties between single crystals and polycrystals. Manipulating the grain boundary to realize good thermoelectric properties in polycrystals similar as those of single crystals is a long-standing task, but it is quite challenging. Herein, we develop a liquid-phase sintering strategy to successfully introduce Mg<sub>2</sub>Cu nano-sintering-aid into the grain boundaries of Mg<sub>3</sub>(Bi, Sb)<sub>2</sub>-based materials. The nano-aid helps to enlarge the average grain size to 23.7 μm and effectively scatter phonons, leading to excellent electrical transports similar as those of single crystals and ultralow lattice thermal conductivity as well as exceptional thermoelectric figure of merit (1.5 at 500 K) and conversion efficiency (7.4% under temperature difference of 207 K). This work provides a simple but effective strategy for the fabrication of high-performance polycrystals for large-scale applications.