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Title: Thermoelectric properties of AMg 2X 2, AZn 2Sb 2 (A = Ca, Sr, Ba; X = Sb, Bi), and Ba 2ZnX 2 (X = Sb, Bi) Zintl compounds

In this paper, we report a theoretical investigation of the electronic structure and transport properties of eleven Zintl compounds including nine 122 phases (AMg 2X 2, AZn 2Sb 2 (A = Ca, Sr, Ba; X = Sb, Bi)) and two 212 phases (Ba 2ZnX 2 (X = Sb, Bi)). The electronic structures and electrical transport properties are studied using ab initio calculations and semi-classical Boltzmann theory within the constant relaxation time approximation. All the compounds are semiconducting. We find that the n-type 122 phases with the CaAl 2Si 2 structure type show better performance than p-type materials due to the multi-valley degeneracy with anisotropic carrier pockets at and near the conduction band minimum. The pocket anisotropy is beneficial in achieving high conductivity and Seebeck coefficient simultaneously. This mechanism yields substantial improvement in the power factor. Finally, the general performance of 212 phases is inferior to that of the 122 phases, with the Ba 2ZnSb 2 compound showing better performance.
Authors:
 [1] ; ORCiD logo [1]
  1. Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
Publication Date:
Grant/Contract Number:
SC0001299
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 5; Journal Issue: 18; Journal ID: ISSN 2050-7488
Publisher:
Royal Society of Chemistry
Research Org:
Univ. of Missouri, Columbia, MO (United States); Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1399476