Thermoelectric properties of multi-walled carbon nanotube-embedded Cu2S thermoelectric materials

Cuprous sulfide (Cu2S)/carbon nanotube (CNT) composites were successfully fabricated using a simple one-step ultrasonic reaction method in this study. Morphological observation confirmed that the CNTs were homogeneously embedded into Cu2S matrix, therefore the thermoelectric performance of Cu2S was enhanced significantly. Experimental results demonstrated strong phonon scattering caused by newly formed interfaces and boundaries between the Cu2S host material and CNT dispersoids, resulting in reduced thermal conductivity lower than 0.4W/m/K at 448-798K. In addition, owing to energy barrier filtering, the Seebeck coefficient increased to 388 mu V/K at 800K, which was 171% higher than that of pure Cu2S. With a CNT molar ratio of 10%, the highest ZT value of the composites reached 0.74at 750K, which was 1.3-fold higher than that of pure Cu2S because of the decreased thermal conductivity and enhanced Seebeck coefficient. The present study can be extended to improve the thermoelectric performance of Cu2-xS-based materials.