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Enhanced thermoelectric properties of YbZn2Sb2-xBix through a synergistic effect via Bi-doping
Zhang, Xiong1,3,4; Gu, Haoshuang3; Zhang, Yu4; Guo, Lijie1; Yang, Juntao4; Luo, Shijun4; Lu, Xu1; Chen, Kansong3; Chai, Hongxiang6; Wang, Guoyu5
2019-10-15
摘要Recently, extensive research has been done to explore the potential thermoelectric performance of p-Type Zintl compounds AB(2)Sb(2) (A = Ca, Yb, Eu, Sr, Mg; B = Zn, Mn, Cd, Mg), mainly focus on A-site substitution and/or B-site substitution effect. Herein, we report that both power factors and thermal conductivities are simultaneously optimized to increase ZT values via substitution of Sb atoms with the isoelectronic Bi atoms in YbZn2Sb2-xBix compounds. We found that the power factor could be enhanced by 27%, as a result of improved electrical conductivities and the maintained Seebeck coefficients. The former is obtained from an increase of carrier density through a shift of Fermi level via Bi doping, which is supported by XPS analysis. The Seebeck coefficients are maintained due to the increased effective mass. Moreover, the lowest lattice thermal conductivity (0.47 Wm(-1) K-1 at 723K) is below the lattice thermal conductivity limit due to enhanced phonon scattering via Bi-doping, which is analyzed by the Callaway model. Benefiting from the synergistic effect, the ZT of Bi-doping samples are significantly enhanced compared with that of the pristine one. These results probably offer a synergistic strategy to enhance ZT for p-Type Zintl compounds AB(2)Sb(2) and other high-efficiency thermoelectric materials.
关键词Zintl compounds Thermoelectric Fermi level Effective mass Callaway model
DOI10.1016/j.cej.2019.05.206
发表期刊CHEMICAL ENGINEERING JOURNAL
ISSN1385-8947
卷号374页码:589-595
通讯作者Wang, Guoyu(guoyuw@cigit.ac.cn) ; Zhang, Xiao(seashellemma@163.com) ; Zhou, Xiaoyuan(xiaoyuan2013@cqu.edu.cn)
收录类别SCI
WOS记录号WOS:000477652900053
语种英语