Concerted Rattling in CsAg5Te3 Leading to Ultralow Thermal Conductivity and High Thermoelectric Performance

• Published in: Angewandte Chemie International Edition Vol. 55; no. 38; pp. 11431 - 11436
• Main Authors: Lin, Hua, Tan, Gangjian, Shen, Jin-Ni, Hao, Shiqiang, Wu, Li-Ming, Calta, Nicholas, Malliakas, Christos, Wang, Si, Uher, Ctirad, Wolverton, Christopher, Kanatzidis, Mercouri G.
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 12.09.2016; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Coefficients; concerted rattling; Conductivity; CsAg5Te3; Direct power generation; Electrical conductivity; Electrical resistivity; Electricity; Energy; Energy conversion efficiency; Energy management; Figure of merit; Heat; Heat conductivity; Heat transfer; Ions; Scattering; State of the art; Temperature; Temperature effects; Thermal conductivity; Thermoelectric materials; Transport properties; tunnel structure; ultralow thermal conductivity
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201605015

Thermoelectric (TE) materials convert heat energy directly into electricity, and introducing new materials with high conversion efficiency is a great challenge because of the rare combination of interdependent electrical and thermal transport properties required to be present in a single material. The TE efficiency is defined by the figure of merit ZT=(S2σ) T/κ, where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the total thermal conductivity, and T is the absolute temperature. A new p‐type thermoelectric material, CsAg5Te3, is presented that exhibits ultralow lattice thermal conductivity (ca. 0.18 Wm−1 K−1) and a high figure of merit of about 1.5 at 727 K. The lattice thermal conductivity is the lowest among state‐of‐the‐art thermoelectrics; it is attributed to a previously unrecognized phonon scattering mechanism that involves the concerted rattling of a group of Ag ions that strongly raises the Grüneisen parameters of the material. A p‐type thermoelectric material, CsAg5Te3, is presented. It exhibits ultralow thermal conductivity (ϰtol≈0.18 Wm−1 K−1) and a high figure of merit (ZT≈1.5 at 727 K). The low thermal conductivity is attributed to a previously unrecognized phonon scattering mechanism that involves the rattling of Ag ions, strongly raising the Grüneisen parameters of the material.