Abstract
In this work, we investigated the effect of nanostructuring on the thermoelectric and thermal properties of nonstoichiometric solid splavs doped with copper sulfides with potassium. The synthesized alloys K 0.01 Cu 1.96 S, K 0.02 Cu 1.95 S, K 0.03 Cu 1.94 S, K 0.04 Cu 1.93 S, K 0.05 Cu 1.94 S are nanocomposite. The crystallite sizes of the synthesized powder, as estimated from the half-width of X-ray diffraction lines, range from 7 to 180 nm. Sample K 0.01 Cu 1.96 S is a mixture of phases consisting of chalcocite Cu 2 S (82%), jarleite Cu 1.96 S (12%), anilite Cu 1.75 S (6%). The composition of samples K 0.02 Cu 1.95 S and K 0.03 Cu 1.94 S includes the most common phases of copper sulfides - chalcocite Cu 2 S , jarleite Cu 1.96 S, digenite Cu 1.80 S. Samples K 0.04 Cu 1.93 S and K 0.05 Cu 1.94 S consist of jarleite Cu 1.96 S, digenite Cu 1.80 S and potassium copper sulfide KCu 4 S 3 phases. In a practical sense, the extremely low thermal conductivity values (from 0.16 to 0.80 W/m · K) found in the range of 300–700 K for nanocomposite samples K 0.02 Cu 1.95 S and K 0.03 Cu 1.94 S are very favorable for achieving high thermoelectric figure of merit ZT material.