首页|Origin of low lattice thermal conductivity in promising ternary PbmBi2S3+m(m=1-10)thermoelectric materials

Origin of low lattice thermal conductivity in promising ternary PbmBi2S3+m(m=1-10)thermoelectric materials

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Ternary Pb-Bi-S compounds emerge as potential thermoelectric materials owing to low thermal conduc-tivity,but the origin of their intrinsic low lattice thermal conductivities lacks further investigation.Herein,a series of ternary PbmBi2S3+m(m=1-10)compounds are synthesized and their crystal structure evolu-tions with increasing m values are clearly unclosed.The room-temperature lattice thermal conductivities in PbBi2S4,Pb3Bi2S6 and Pb6Bi2S9 can reach at 0.57,0.56 and 0.80 W m-1 K-1,respectively,outperform-ing other ternary sulfur-based compounds.Theoretical calculations show that the low lattice thermal conductivities in PbmBi2S3+m(m=1-10)mainly originate from soft phonon dispersion caused by strong lattice anharmonicity,and both asymmetric chemical bond and lone pair electrons(Pb 6s2 and Bi 6s2)can favorably block phonon propagation.Furthermore,the elastic measurements also confirm relatively low sound velocities and shear modulus,and the Grüneisen parameter(y)calculated by sound velocities can reach at 1.67,1.85 and 1.94 in PbBi2S4,Pb3Bi2S6 and Pb6Bi2S9,respectively.Finally,the intrinsic low lattice thermal conductivities in PbmBi2S3+m(m=1-10)contribute to promising thermoelectric perfor-mance,and the maximum ZT values of 0.47,0.38 and 0.45 can be achieved in undoped PbBi2S4,Pb3Bi2S6 and Pb6Bi2S9,respectively.

Crystal structure evolutionLattice thermal conductivityPhonon dispersionLattice anharmonicityLone pair electrons

Wei Liu、Biao Chen、Liqing Xu、Dongyang Wang、Changsheng Xiang、Xiangdong Ding、Yu Xiao

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State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China

State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China

School of Materials and Energy,University of Electronic Science and Technology of China,Chengdu 611731,China

Henan Key Laboratory of Diamond Optoelectronic Materials and Devices,Key Laboratory of Material Physics,Ministry of Education,School of Physics,Zhengzhou University,Zhengzhou 450052,China

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2024

10.1016/j.jmst.2024.02.030

材料科学技术(英文版)
中国金属学会 中国材料研究学会 中国科学院金属研究所

材料科学技术(英文版)

CSTPCD
影响因子：0.657
ISSN：1005-0302
年,卷(期)：2024.198(31)