Synergistic modulation of electrical and thermal properties of Cu1.8S bulk materials via nanostructuring and band engineering

Abstract Digenite (Cu1.8S) is a subject of increasing interest as a potential p-type thermoelectric material because of its element abundance, low cost and environmental friendliness. However, its thermoelectric properties are limited by high thermal conductivity. In this work, the Cu1.8S with x wt% Bi2Te3 (x = 0, 0.5, 1, 3, 5) samples were prepared by combining mechanical alloying (MA) and spark plasma sintering (SPS) technology. The results reveal that Bi2Te3 addition can effectively optimize the thermoelectric properties of Cu1.8S materials by tuning the carrier concentration and introducing nanoprecipitates. As a result, the optimal Cu1.8S +1 wt% Bi2Te3 sample presents an excellent performance, with relatively high ZT value of 1.1 (at 773 K), which is approximately 2.4 times that of pure Cu1.8S.