Significant role of nanoscale Bi-rich phase in optimizing thermoelectric performance of Mg3Sb2  

作　　者：Yang Wang Xin Zhang Yan-Qin Liu Jiu-Xing Zhang Ming Yue 王杨;张忻;刘燕琴;张久兴;岳明(Key Laboratory of Advanced Functional Materials,Ministry of Education,College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China;School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]Key Laboratory of Advanced Functional Materials,Ministry of Education,College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China [2]School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China

出　　处：《Chinese Physics B》2020年第6期405-410,共6页中国物理B（英文版）

基　　金：National Natural Science Foundation of China(Grant Nos.51371010,51572066,and 50801002);the Beijing Municipal Natural Science Foundation,China(Grant No.2112007);the Fundamental Research Funds for the Central Universities(Grant No.PXM2019-014204-500032);the Science Fund from the Advanced Space Propulsion Laboratory of BICE and Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology,China(Grant No.LabASP-2018-09).

摘　　要：Mg3Sb1.5Bi0.5-based alloys have received much attention,and current reports on this system mainly focus on the modulation of doping.However,there lacks the explanation for the choice of Mg3Sb1.5Bi0.5 as matrix.Here in this work,the thermoelectric properties of Mg3Sb2-xBix(0.4≤x≤0.55)compounds are systematically investigated by using the first principles calculation combined with experiment.The calculated results show that the band gap decreases after Bi has been substituted for Sb site,which makes the thermal activation easier.The maximum figure of merit(ZT)is 0.27 at 773 K,which is attributed to the ultra-low thermal conductivity 0.53 W·m-1·K-1 for x=0.5.The large mass difference between Bi and Sb atoms,the lattice distortion induced by substituting Bi for Sb,and the nanoscale Bi-rich particles distributed on the matrix are responsible for the reduction of thermal conductivity.The introduction of Bi into Mg3Sb2-based materials plays a vital role in regulating the transport performance of thermoelectric materials.

关 键 词：first principles calculations nanoscale Bi-rich phase Mg3Sb2 thermoelectric performance 

分 类 号：O469[理学—凝聚态物理]