Probing the Effect of MWCNT Nanoinclusions on the Thermoelectric Performance of Cu₃SbS₄ Composites

Abstract

Recently, copper-based chalcogenides, especially sulfides, have attracted considerable attention due to their inexpensive, earth-abundance, nontoxicity, and good thermoelectric performance. Cu 3 SbS 4 is one such kind with p-type conductivity and high phase stability for potential medium-temperature applications. In this article, the effect of a multiwalled carbon nanotube (MWCNT) on the thermoelectric parameters of Cu 3 SbS 4 is studied. A facile synthesis route of mechanical alloying (MA), followed by hot pressing (HP) was utilized to achieve dense and fine-grain samples. Adding the optimal amount of MWCNT nanoinclusions in Cu 3 SbS 4 enhanced the Seebeck coefficient by carrier energy filtering and reduced the thermal conductivity by strong phonon scattering mechanisms. This synergistic optimization helped achieve the maximum figure of merit (ZT) of 0.43 in the 3 mol % MWCNT nanoinclusion composite sample, which is 70% higher than the pristine Cu 3 SbS 4 at 623 K. In addition, enhancement in mechanical stability is observed with the increasing nanoinclusion concentration. Dispersion strengthening and grain boundary hardening mechanisms help improve mechanical stability in the nanocomposite samples. Apart from the enhanced mechanical stability, our study highlights that the incorporation of multiwalled CNT nanoinclusions boosted the thermoelectric performance of Cu 3 SbS 4 , and the same strategy can be extended to other next-generation and conventional thermoelectric materials.

Dispersion of InSb Nanoinclusions in Cu3SbS4 for Improved Stability and Thermoelectric Efficiency

“…Nanoinclusions contribute to the reduction of thermal conductivity by utilizing interfacial boundary-based phonon scattering. [4,5,20,23] Given the similarity in sizes of the nanoinclusions with the phonon mean free path (MFP of phonons is greater than electrons), these interfacial boundaries effectively scatter phonons more than electrons. [24] Indium antimonide (InSb) intermetallic as a nanoinclusions can improve the thermoelectric efficiency of materials and enhance the material's ZT simultaneously.…”