Achieving high room-temperature thermoelectric performance in cubic AgCuTe

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-03, Vol.8 (9), p.479-4799
• Main Authors: Jiang, Jing, Zhu, Hangtian, Niu, Yi, Zhu, Qing, Song, Shaowei, Zhou, Ting, Wang, Chao, Ren, Zhifeng
• Format: Article
• Language: English
• Subjects: Chalcogenides; Copper; Electric power generation; Face centered cubic lattice; High temperature; Low temperature; Operating temperature; Power factor; Room temperature; Temperature gradients; Thermal conductivity; Thermal stability; Thermoelectric materials
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta12954e

Although there has been significant progress in developing high-temperature thermoelectric materials, seeking promising near-room-temperature candidates has been extremely difficult, and the discovery of such materials, which would be beneficial for low-grade waste-heat power generation and cooling near room temperature, has been rarely reported. Here we report the enhanced near-room-temperature performance ( ZT max = ∼1.1 at 350 K, ZT avg = ∼1.0 between 300 K and 673 K) of copper chalcogenide (AgCu) 0.995 Te 0.9 Se 0.1 by successfully stabilizing the face-centered cubic (FCC) phase at room temperature. Surprisingly low lattice thermal conductivity (∼0.4 W m −1 K −1 ) and a good power factor (∼13.8 μW cm −1 K −2 ) are simultaneously achieved near room temperature due to the unique properties of the FCC phase. A competitive conversion efficiency of 11% is obtained in a (AgCu) 0.995 Te 0.9 Se 0.1 -based single leg at a low temperature difference of 400 K. The high thermal stability and low operating temperature, combined with the economically competitive efficiency, will greatly promote the application of (AgCu) 0.995 Te 0.9 Se 0.1 -based devices in power generation from low- and medium-grade waste heat. The results also indicate a new strategy to improve the near-room-temperature performance and stability of copper chalcogenide thermoelectric materials and a new direction for further research. Average ZT of near unity provides a competitive thermoelectric conversion efficiency of ∼12% at low temperature difference of 400 K.