Preparation of single-phase pb-filled chevrel-phase sulfide and its thermoelectric properties

Abstract

Pb-filled Chevrel-phase sulfides PbMo6S8-y were prepared from PbS, Mo, and MoS2. The single phase was formed in the nominal composition PbMo6S7.8 (8 - y = 7:8). While the secondary PbS and Mo phases were formed in sulfur-poor compositions, the secondary MoS2 phase was formed in sulfur-rich compositions. The sintered sample had a positive Seebeck coefficient. The Seebeck coefficient and electrical resistivity increased with temperature. Furthermore, the thermal conductivity was dominated by the electronic thermal conductivity, and the complex crystal structure yielded a low lattice thermal conductivity. The thermoelectric figure of merit ZT increased with temperature, reaching a value of 0.08 at 850 K. © 2011 The Thermoelectrics Society of Japan.