Highly enhanced thermoelectric and mechanical performance of copper sulfides via natural mineral <i>in-situ</i> phase separation
Yan Xi, Hongjiang Pan, Yixin Zhang, Tianyu Yang, Yangwei Wang, Kun Huang, Chong‐Yu Wang, Jing Feng, Zhen‐Hua Ge
Abstract
The precipitates of in-situ phase separation play an important role in enhancing the thermoelectric properties of copper sulfides by suppressing phonon transmission. In this study, Cu<sub>1.8</sub>S composites were fabricated by melting reaction and spark plasma sintering. The complex structures, micron-PbS, Sb<sub>2</sub>S<sub>3</sub>, nano-FeS and multiscale pores, originate from the introduction of FePb<sub>4</sub>Sb<sub>6</sub>S<sub>14</sub> into the Cu<sub>1.8</sub>S matrix. Using effective element (Fe) doping and multiscale precipitates, the Cu<sub>1.8</sub>S+0.5 wt.% FePb<sub>4</sub>Sb<sub>6</sub>S<sub>14</sub> bulk composite reached a high <em>ZT</em> value of 1.1 at 773 K. Furthermore, the modulus obtained for this sample was approximately about 40.27 Gpa, which was higher than of the pristine sample. This study provides a novel strategy for realizing heterovalent doping while forming various precipitates via in-situ phase separation by the natural minerals, which has been proven to be effective in improving the thermoelectric and mechanical performance of copper sulfides and is worth promoting in other thermoelectric systems.