Impact of sintering method on Cu₃SbS₄ thermoelectric performance

Tellurium-based commercial thermoelectric (TE) devices are widely employed in waste heat recovery systems. Due to the toxic nature and expensiveness of tellurium, finding alternative materials for TE devices has become necessary. Among various developed TE materials, the ternary copper chalcogenide-based famatinite (Cu₃SbS₄) compound is one of the viable alternatives for cutting-edge TE materials. Cu₃SbS₄ has a poor structural complexion that must be optimized to reduce thermal conductivity and improve TE performance. In this regard, we investigated the effect of sintering method on thermoelectric Cu₃SbS₄. Mechanical alloying followed by spark plasma sintering or hot pressing generated the nanostructure morphology, i.e., nano-grain structure. We analyzed the thermoelectric properties of the synthesized Cu₃SbS₄ materials in the temperature range 300–623 K. Finally, demonstrated the spark plasma sintering (SPS) showed superior thermoelectric performance than hot pressing (HP) sintering in Cu₃SbS₄ due to the finer grain size and better densification. Our study demonstrated that the mechanical alloying followed by SPS sintering in Cu₃SbS₄ could produce nano-grained, efficient, densified, and fast-processing thermoelectric materials.