Achieving high thermoelectric performance of Cu_1.8S composites with WSe₂ nanoparticles

Polycrystalline p-type Cu_1.8S composites with WSe₂ nanoparticles were fabricated by the mechanical alloying method combined with the spark plasma sintering technique. The Seebeck coefficient was significantly enhanced by the optimized carrier concentration, while the thermal conductivity was simultaneously decreased due to the refined grain and WSe₂ nanoparticles. An enhanced Seebeck coefficient of 110 μV K^-1 and a reduced thermal conductivity of 0.68 W m^-1 K^-1 were obtained for the Cu_1.8S + 1 wt% WSe₂ sample at 773 K, resulting in a remarkably enhanced peak ZT of 1.22 at 773 K, which is 2.5 times higher than that (0.49 at 773 K) of a pristine Cu_1.8S sample. The cheap and environmentally friendly Cu_1.8S-based materials with enhanced properties may find promising applications in thermoelectric devices.