Thermoelectric Properties of Cu<sub>2</sub>SnSe<sub>3</sub>-Based Composites Containing Melt-Spun Cu–Te
oleh: Degang Zhao, Lin Wang, Di Wu, Lin Bo
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2019-09-01 |
Deskripsi
In this study, the Cu−Te alloy ribbons containing nanocrystalline structures were prepared by melt spinning (MS), and were composed of Cu<sub>2−<i>x</i></sub>Te, Cu<sub>2</sub>Te, Cu<sub>3−<i>x</i></sub>Te, and CuTe phases. Crystal grains on both sides of the ribbons were uniformly distributed and the grain size of the contact surface was about 400 nm. The Cu−Te powder was incorporated into the Cu<sub>2</sub>SnSe<sub>3</sub> powder by the ball milling process and the Cu−Te/Cu<sub>2</sub>SnSe<sub>3</sub> thermoelectric composite was prepared by spark plasma sintering (SPS). With the amount of Cu−Te powder increasing, the carrier concentration of the Cu−Te/Cu<sub>2</sub>SnSe<sub>3</sub> composite increased, while the carrier mobility and electrical conductivity initially increased and then decreased. Compared to the Seebeck coefficient of the Cu<sub>2</sub>SnSe<sub>3</sub> matrix, the Seebeck coefficient of the Cu−Te/Cu<sub>2</sub>SnSe<sub>3</sub> samples increased slightly. Moreover, the Cu−Te/Cu<sub>2</sub>SnSe<sub>3</sub> composites had lower thermal conductivity and lattice thermal conductivity over the whole temperature range. The lattice thermal conductivity of the 0.8 vol.% Cu−Te/Cu<sub>2</sub>SnSe<sub>3</sub> composite achieved the lowest value of 0.22 W/m·K, which was 78% lower than that of the Cu<sub>2</sub>SnSe<sub>3</sub> matrix. The maximum figure of merit of the 0.8 vol.% Cu−Te/Cu<sub>2</sub>SnSe<sub>3</sub> composite was 0.45 at 700 K.