Thermoelectric properties of p-type pseudo-binary (Ag0.365Sb0.558Te)x–(Bi0.5Sb1.5Te3)1−x (x=0–1.0) alloys prepared by spark plasma sintering

In this paper, pseudo-binary (Ag0.365Sb0.558Te)x–(Bi0.5Sb1.5Te3)1−x (x=0–1.0) alloys were prepared using spark plasma sintering technique, and the composition-dependent thermoelectric properties were evaluated. Electrical conductivities range from 7.9×104 to 15.6×104 Ω−1 m−1 at temperatures of 507 and 318 K, respectively, being about 3.0 and 8.5 times those of Bi0.5Sb1.5Te3 alloy at the corresponding temperatures. The optimal dimensionless figure of merit (ZT) of the sample with molar fraction x=0.025 reaches 1.1 at 478 K, whereas that of the ternary Bi0.5Sb1.5Te3 alloy is 0.58 near room temperature. The results also reveal that a direct introduction of Ag0.365Sb0.558Te in the Bi–Sb–Te system is much more effective to the property improvement than naturally precipitated Ag0.365Sb0.558Te in the Ag-doped Ag–Bi–Sb–Te system.