Multiphase microstructures enable high-performance BiSbSe3/Cu thermoelectric composites

Abstract

Te-free BiSbSe3 thermoelectric materials exhibit promising potential for medium-temperature applications due to their intrinsically low lattice thermal conductivity and multiple conduction bands. However, the inferior electrical conductivity results in a near-zero thermoelectric figure of merit ZT value. Herein, we propose a nano-Cu composite-driven strategy for engineering multiphase microstructures, enabling the enhancement of thermoelectric performance. Narrow-bandgap CuSbSe2 and BiSe phases effectively modulate interfacial energy barriers for BiSbSe3/Cu composites. Synchrotron X-ray pair distribution function analysis reveal that the interstitial Cu atoms enhances the short-range order while suppressing the formation of Se vacancies, thereby promoting lattice plainification and improving electrical transport properties. Concurrently, defect engineering introduces full-frequency phonon scattering centers, including heterogeneous interfaces, nanoscale defects, and point defects, collectively reducing the lattice thermal conductivity. Combining with the enhanced power factor, BiSbSe3+0.2%Cu composite along parallel to the hot-pressing sintering direction attains a peak ZT of ~0.88 at 723 K, representing a nearly 14-fold enhancement than that of pristine BiSbSe3. This work establishes nano-Cu composite-driven multiphase microstructures engineering as a promising paradigm for enhancing thermoelectric performance, offering a transferable framework for other thermoelectric systems.

Supplementary files

Article information

Article type
Paper
Submitted
19 Jun 2025
Accepted
30 Jul 2025
First published
31 Jul 2025

J. Mater. Chem. A, 2025, Accepted Manuscript

Multiphase microstructures enable high-performance BiSbSe3/Cu thermoelectric composites

X. Shi, S. Cao, Y. Yan, Q. Jiang, S. Tan, H. Kang, E. Guo, Z. Chen, R. Chen and T. Wang, J. Mater. Chem. A, 2025, Accepted Manuscript , DOI: 10.1039/D5TA04980F

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