Thermoelectric Properties of Chevrel-Type Sulfides AMo6S8. (A = Fe, Ni, Ag, Zn, Sn, Pb, Cu).

Abstract

Thermoelectric properties of Chevrel-type sulfides AMo6S8 (A=Fe, Ni, Ag, Zn, Sn, Pb, Cu) were investigated with respect to many advantageous characteristics of the Chevrel compounds for thermoelectric applications. The electrical conductivity, σ, was 102.5S·cm-1<σ<103S·cm-1 for most of the samples from room temperature to 1000°C; AgMo6S8 gave the largest σ up to 250°C. The Seebeck coefficient, S, was positive for all the samples, indicating the p-type conduction. All the S values were 10μV·K-1<S<80μV·K-1, and AgMo6S8 showed the smallest S, probably owing to the higher hole concentration for A=Ag compared to other samples. The maximum S2σ value was attained by SnMo6S8, reaching ca. 1.7×10-4W·m-1·K-2 at 800°C. All the κ values were 1W·m-1·K-1<κ<3W·m-1·K-1 from room temperature to 1000°C. The maximum Z value was ca. 0.07×10-3K-1 attained by SnMo6S8 at 800°C.