Synergistic boost of output power density and efficiency in In-Li-codoped SnTe.
basic_science · Level V
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- Record sourced from PubMed, PMID 31611406.
- Also identified by DOI 10.1073/pnas.1911085116 and PMC identifier 6825297.
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Abstract
We report enhanced thermoelectric performance of SnTe by further increasing its intrinsic high carrier concentration caused by Sn vacancies in contrast to the traditional method. Along with In<sub>2</sub>Te<sub>3</sub> alloying, which results in an enhanced Seebeck coefficient, Li<sub>2</sub>Te is added to further increase the carrier concentration in order to maintain high electrical conductivity. Finally, a relatively high <i>PF</i> <sub><i>ave</i></sub> of ∼28 μW cm<sup>-1</sup> K<sup>-2</sup> in the range between 300 and 873 K is obtained in an optimized SnTe-based compound. Furthermore, nanoprecipitates with extremely high density are constructed to scatter phonons strongly, resulting in an ultralow lattice thermal conductivity of ∼0.45 W m<sup>-1</sup> K<sup>-1</sup> at 873 K. Given that the <i>Z</i> value is temperature dependent, the (<i>ZT</i>) <sub><i>eng</i></sub> and (<i>PF</i>) <sub><i>eng</i></sub> values are adopted to accurately predict the performance of this material. Taking into account the Joule and Thomson heat, output power density of ∼5.53 W cm<sup>-2</sup> and leg efficiency of ∼9.6% are calculated for (SnTe)<sub>2.94</sub>(In<sub>2</sub>Te<sub>3</sub>)<sub>0.02</sub>-(Li<sub>2</sub>Te)<sub>0.045</sub> with a leg length of 4 mm and cold- and hot-side temperatures of 300 and 870 K, respectively.