Enhanced Thermoelectric Performance of Cu<sub>2</sub>Se via Nanostructure and Compositional Gradient

oleh: Lin Bo, Fujin Li, Yangbo Hou, Min Zuo, Degang Zhao

Format: Article
Diterbitkan: MDPI AG 2022-02-01

Deskripsi

Forming co-alloying solid solutions has long been considered as an effective strategy for improving thermoelectric performance. Herein, the dense Cu<sub>2−<i>x</i></sub>(MnFeNi)<i><sub>x</sub></i>Se (<i>x</i> = 0–0.09) with intrinsically low thermal conductivity was prepared by a melting-ball milling-hot pressing process. The influences of nanostructure and compositional gradient on the microstructure and thermoelectric properties of Cu<sub>2</sub>Se were evaluated. It was found that the thermal conductivity decreased from 1.54 Wm<sup>−1</sup>K<sup>−1</sup> to 0.64 Wm<sup>−1</sup>K<sup>−1</sup> at 300 K via the phonon scattering mechanisms caused by atomic disorder and nano defects. The maximum <i>zT</i> value for the Cu<sub>1.91</sub>(MnFeNi)<sub>0.09</sub>Se sample was 1.08 at 750 K, which was about 27% higher than that of a pristine sample.