Potential for high thermoelectric performance in n-type Zintl compounds [electronic resource] : A case study of Ba doped KAlSb<sub>4</sub>.
- Washington, D.C. : United States. Dept. of Energy. Office of Energy Efficiency and Renewable Energy, 2017. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 4,036-4,046 : digital, PDF file
- Additional Creators:
- National Renewable Energy Laboratory (U.S.), United States. Department of Energy. Office of Energy Efficiency and Renewable Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- High-throughput calculations (first-principles density functional theory and semi-empirical transport models) have the potential to guide the discovery of new thermoelectric materials. Herein we have computationally assessed the potential for thermoelectric performance of 145 complex Zintl pnictides. Of the 145 Zintl compounds assessed, 17% show promising n-type transport properties, compared with only 6% showing promising p-type transport. We predict that n-type Zintl compounds should exhibit high mobility μ<sub>n</sub> while maintaining the low thermal conductivity κ<sub>L</sub> typical of Zintl phases. Thus, not only do candidate n-type Zintls outnumber their p-type counterparts, but they may also exhibit improved thermoelectric performance. From the computational search, we have selected n-type KAlSb<sub>4</sub> as a promising thermoelectric material. Synthesis and characterization of polycrystalline KAlSb<sub>4</sub> reveals non-degenerate n-type transport. With Ba substitution, the carrier concentration is tuned between 10<sup>18</sup> and 10<sup>19</sup> e<sup>–</sup> cm<sup>–3</sup> with a maximum Ba solubility of 0.7% on the K site. High temperature transport measurements confirm a high μ<sub>n</sub> (50 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>) coupled with a near minimum κ<sub>L</sub> (0.5 W m<sup>–1</sup> K<sup>–1</sup>) at 370 °C. Together, these properties yield a <i>zT</i> of 0.7 at 370 °C for the composition K<sub>0.99</sub>Ba<sub>0.01</sub>AlSb<sub>4</sub>. As a result, based on the theoretical predictions and subsequent experimental validation, we find significant motivation for the exploration of n-type thermoelectric performance in other Zintl pnictides.
- Published through SciTech Connect., 01/11/2017., "nrel/ja--5k00-68158", Journal of Materials Chemistry. A 5 8 ISSN 2050-7488; JMCAET AM, and Brenden R. Ortiz; Prashun Gorai; Lakshmi Krishna; Rachel Mow; Armando Lopez; Robert McKinney; Vladan Stevanovic; Eric S. Toberer.
- Funding Information:
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