Enhanced thermoelectric performance of Bi–Sb–Te alloys via SiO₂ nanoparticle-induced multiscale phonon scattering
Journal
Journal of Alloys and Compounds
Journal Volume
1070
Start Page
188424
ISSN
09258388
Date Issued
2026-06-05
Author(s)
Abstract
Suppressing lattice thermal conductivity without sacrificing electronic transport remains a fundamental challenge for enhancing the thermoelectric performance of Bi0.5Sb1.5Te3-x alloys near room temperature. Here, a nanocomposite engineering strategy is proposed by integrating rapid solidification via melt spinning with the incorporation of SiO2 nanoparticles (NPs) to achieve effective phonon scattering across multiple length scales. Melt spinning produces compositionally homogeneous powders with refined nanoscale grains, while uniformly dispersed SiO2 NPs introduce thermally stable oxide–matrix interfaces that selectively scatter heat-carrying phonons. Subsequent consolidation by spark plasma sintering preserves the refined microstructure and suppresses grain coarsening. Through compositional optimization, Bi0.5Sb1.5Te3-x with x = 0.15 (BST) exhibits the most favorable balance between electrical and thermal transport. With the incorporation of 2 vol% SiO2 NPs, the thermal conductivity is reduced from 1.26 to 1.10 W m−1 K−1 at 400 K, while the electrical conductivity and Seebeck coefficient remain largely preserved. Consequently, the maximum dimensionless figure of merit (ZT) increases from 1.18 to 1.55 at 400 K, representing an improvement of approximately 25% over the pristine alloy and placing the performance among the higher values reported for oxide-modified bulk BST systems. These results demonstrate that oxide nanoparticle–assisted multiscale phonon scattering is an effective approach for overcoming the lattice thermal conductivity bottleneck in high-performance BST-based thermoelectric materials.
Subjects
Bi0.5Sb1.5Te3-x (x = 0.15)
Low-temperature Bi2Te3
Melt-spinning
SiO2 nanoparticles
Thermoelectric materials
Publisher
Elsevier Ltd
Type
journal article