Study of the Stability of Properties of Low-Temperature Nanostructured Thermoelectric Materials Based on BiTeSe and BiSbTe

A promising method for increasing the efficiency of thermoelectric energy converters as alternative energy sources is nanostructuring of thermoelectric materials used to manufacture thermoelements. The widespread use of thermoelectric devices is hampered by their low efficiency, which is determined by the thermoelectric figure of merit ZT of thermoelectric materials. The paper investigates the stability of the properties of low-temperature nanostructured thermoelectric materials based on solid solutions of Bi2Te2.8Se0.2 (0.16 wt % CdCl2) of the n-type and Bi0.5Sb1.5Te3 (2.2 wt % Te and 0.16 wt % TeI4) of the p-type obtained as a result of grinding in a planetary ball mill and subsequent compaction by spark plasma sintering. Thermoelectric materials Bi2Te2.8Se0.2 and Bi0.5Sb1.5Te3 have high maximum values of thermoelectric figure of merit ZT, equal to 1.17 and 1.23, respectively. Thermal stability of the properties of Bi2Te2.8Se0.2 and Bi0.5Sb1.5Te3 materials was investigated using multiple measurements using differential scanning calorimetry and thermogravimetry. Thermoelectric and electrophysical characteristics of thermoelectric materials were obtained at temperatures up to 500 K. It was established that nanostructuring does not have a significant effect on the thermal stability of the studied low-temperature nanostructured thermoelectric materials.