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A Dual Role by Incorporation of Magnesium in YbZn 2 Sb 2 Zintl Phase for Enhanced Thermoelectric Performance
Author(s) -
Zhang Zongwei,
Yan Yirui,
Li Xiaofang,
Wang Xinyu,
Li Juan,
Chen Chen,
Cao Feng,
Sui Jiehe,
Lin Xi,
Liu Xingjun,
Xie Guoqiang,
Zhang Qian
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202001229
Subject(s) - zintl phase , materials science , thermoelectric effect , doping , analytical chemistry (journal) , valence (chemistry) , electrical resistivity and conductivity , crystal structure , thermoelectric materials , seebeck coefficient , effective mass (spring–mass system) , crystallography , thermal conductivity , phase (matter) , thermodynamics , chemistry , optoelectronics , physics , organic chemistry , quantum mechanics , electrical engineering , composite material , engineering , chromatography
1‐2‐2‐type Zintl phase compounds have promising thermoelectric properties because of their complex crystal structures and multiple valence‐band structures. In this work, a series of single phase (Yb 0.9 Mg 0.1 )Mg x Zn 2− x Sb 2 ( x = 0, 0.2, 0.4, 0.6, 0.8, and 1) compounds are prepared by alloying YbZn 2 Sb 2 with 10 at% MgZn 2 Sb 2 and different amounts of YbMg 2 Sb 2 . The incorporation of Mg at the Yb site, as well as at the Zn site, not only leads to an effective orbital alignment confirmed by the dramatically enhanced density of states effective mass and Seebeck coefficients, but also increases the point defect scattering, contributing to a low lattice thermal conductivity ≈0.54 W m −1 K −1 at 773 K. Combined with the optimization of the carrier concentration by Ag doping at the Zn site, a highest ZT value ≈1.5 at 773 K is achieved in (Yb 0.9 Mg 0.1 )Mg 0.8 Zn 1.2 Ag 0.002 Sb 2 , which is higher than that of all the previously reported 1‐2‐2‐type Zintl phase compounds.