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Title: Potential for high thermoelectric performance in n-type Zintl compounds: A case study of Ba doped KAlSb 4

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 n while maintaining the low thermal conductivity κ L 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 4 as a promising thermoelectric material. Synthesis and characterization of polycrystalline KAlSb 4 reveals non-degenerate n-type transport. With Ba substitution, the carrier concentration is tuned between 10 18 and 10 19 e cm –3 with a maximum Ba solubility of 0.7% on the K site. High temperature transport measurements confirm a high μ n (50 cm 2 V –1 s –1) coupled with a near minimum κ L (0.5 W m –1 K –1) at 370 °C. Together, these properties yield a zT of 0.7 at 370 °C for the compositionmore » K 0.99Ba 0.01AlSb 4. 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.« less
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [3] ;  [1] ; ORCiD logo [1] ;  [2] ;  [2]
  1. Colorado School of Mines, Golden, CO (United States)
  2. Colorado School of Mines, Golden, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. Harvey Mudd College, Claremont, CA (United States)
Publication Date:
Report Number(s):
NREL/JA-5K00-68158
Journal ID: ISSN 2050-7488; JMCAET
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 5; Journal Issue: 8; Journal ID: ISSN 2050-7488
Publisher:
Royal Society of Chemistry
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; thermoelectric materials; Zintl pnictides
OSTI Identifier:
1347504