High Thermoelectric Performance and Low Lattice Thermal Conductivity in Lattice-Distorted High-Entropy Semiconductors AgMnSn 1– x Pb x SbTe 4

作者：Zheng Ma, Yubo Luo, Wang Li, Tian Xu, Yingchao Wei, Chengjun Li, Abubakar Yakubu Haruna, Qinghui Jiang, Dan Zhang, Junyou Yang · 发表于：Chemistry of Materials · 年份：2022 · DOI：10.1021/acs.chemmater.2c02344 · 被引用次数：42 · 研究领域：Advanced Thermoelectric Materials and Devices、Thermal properties of materials、Chalcogenide Semiconductor Thin Films

We investigate the structure and thermoelectric properties of a new high-entropy solid solution system AgMnSn 1– x Pb x SbTe 4 ( x = 0, 0.25, 0.5, 0.75, and 1), which crystallizes in the rock-salt NaCl structure with cations Ag, Mn, Sn, Pb, and Sb randomly disordered over the Na site. Our density functional theory calculations indicate that AgMnSn 1– x Pb x SbTe 4 exhibits complex multi-peak valence band structures, whose energy difference is lower than 0.11 eV, leading to effective band convergence and thus high density of states effective mass m * and Seebeck coefficients. As a consequence, AgMnSn 0.25 Pb 0.75 SbTe 4 has a peak ZT of 1.3 at 773 K and a desirable average ZT value of 0.8 in the temperature range of 400–773 K. In addition, we propose the lattice distortion degree (i.e., δ) as an important indicator of thermoelectric performance for high-entropy materials. Specifically, with the gradual increase in δ, the lattice thermal conductivity decreases monotonically from 0.90 W m –1 K –1 for AgMnSnSbTe 4 (i.e., δ = 0.205) to 0.54 W m –1 K –1 for AgMnPbSbTe 4 (i.e., δ = 0.230) at 300 K. Meanwhile, the generalized material parameter B x * / B 0 * and ZT increase monotonically from 1 and 0.11 for δ = 0.205 to 3.15 and 0.29 for δ = 0.230 at 300 K.