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 K0.01Cu1.96S , K0.02Cu1.95S , K0.03Cu1.94S , K0.04Cu1.93S , K0.05Cu1.94S 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 K0.01Cu1.96S is a mixture of phases consisting of chalcocite Cu2S
(82%), jarleite Cu1.96S (12%), anilite Cu1.75S (6%). The composition of samples K0.02Cu1.95S and
K0.03Cu1.94S includes the most common phases of copper sulfides - chalcocite Cu2S , jarleite Cu1.96S ,
digenite Cu1.80S . Samples K0.04Cu1.93S and K0.05Cu1.94S consist of jarleite Cu1.96S , digenite Cu1.80S
and potassium copper sulfide KCu4S3 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 K0.02Cu1.95S and K0.03Cu1.94S are very favorable for achieving high thermoelectric figure of merit ZT material.
