Improvement of mid-temperature ZT in a Bi-Se-Te via a two two-step sintering process

Abstract

There exists a vast choice when considering the selection of thermoelectric materials. The standard classification is based on the temperature range of the application. This study fabricated mid‐temperature Bi-Se-Te using spark plasma sintering (SPS). Consequently, the impact of the sintering conditions on the thermoelectric properties was analyzed. The structural analysis indicated that initial and secondary sintering processes effectively produced the low-temperature thermoelectric material Bi2Se0.45Te2.55. The sintering duration and temperature changes mainly influenced the grain boundary density, with elevated temperatures inducing defects that impacted the performance. Secondary sintering resulted in layered structures with elongated grains, which enhanced the phonon scattering effect. This configuration markedly decreased the thermal conductivity, increasing the ZT value by 60%.