High-performance Bi-Sb-Te thermoelectric materials synthesized via melt spinning and spark plasma sintering for energy harvesting applications

Bi₂Te₃-based materials remain among the most promising thermoelectric candidates for applications in the temperature range of 300–400 K, owing to their high electrical conductivity, low thermal conductivity, chemical stability, and compatibility with scalable fabrication methods. However, conventional crystal growth techniques often lead to elemental segregation and compositional inhomogeneity. In this study, a rapid solidification approach using melt spinning was employed to mitigate segregation, yielding compositionally uniform Bi₂Te₃-based powders with particle sizes below 30 μm and nanometer-scale grain structures. The fabrication process—integrating planetary ball milling, annealing, melt spinning, and spark plasma sintering (SPS)—significantly enhanced phonon scattering, thereby reducing thermal conductivity and improving overall material homogeneity. By systematically adjusting the tellurium content in Bi_0.5Sb_1.5Te_3-X, the composition with x= 0.15 was identified as optimal, achieving a peak dimensionless figure of merit (ZT) of 1.18 at 360 K.