Thermo-Electric-Mechanical Coupling Selects Barrier Layer for Advanced Bismuth Telluride Thermoelectric Generator.
basic_science · Level V
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- Record sourced from PubMed, PMID 40297965.
- Also identified by DOI 10.1002/adma.202503580.
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Abstract
The long-term stability of thermoelectric generators, including those based on Bi<sub>2</sub>Te<sub>3</sub>, is hindered by the lack of ideal thermoelectric barrier materials (TEbMs). Conventional selection methods for TEbMs mainly rely on trial-and-error, which is time-consuming and does not reveal the underlying mechanisms. In this study, a new design principle for selecting TEbMs based on thermo-electric-mechanical coupling is proposed. By combining the phase diagram predictions with the thermal expansion coefficients and electrical resistivities of the potential reactants, the Ni<sub>2</sub>SbTe<sub>2</sub> and NiTe<sub>2</sub> compounds are identified as ideal TEbMs for (Bi,Sb)<sub>2</sub>Te<sub>3</sub> and Bi<sub>2</sub>(Te,Se)<sub>3</sub>, respectively, leading to interfaces with high thermal stability, low contact resistivity, and high strength. The fabricated thermoelectric generator achieves a competitive conversion efficiency of 7.1% and a power density of 0.49 W cm<sup>-2</sup> at hot-side and cold-side temperatures of 523 and 296 K, respectively. Moreover, performance degradation is negligible after 200 h of cycling. This work demonstrates progress toward stable high-performance service, provides the foundation for applications in low-grade heat recovery, and offers new insights for more thermoelectric generators.