Scale-bridging interface design enables high-performance sustainable thermoelectrics.
basic_science · Level V
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- Record sourced from PubMed, PMID 42471338.
- Also identified by DOI 10.1038/s41467-026-75865-1.
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Abstract
Improving energy efficiency and reducing resource waste motivate sustainable thermoelectric technologies for harvesting low-grade heat. Yet achieving high-performance and durable systems remains challenging due to coupled transport and multiscale optimization. Here, we establish a scale-bridging interface-centric design strategy that links macroscopic junction engineering and microscopic interface modulation. Based on n-type Mg<sub>3</sub>(Sb, Bi)<sub>2</sub> as the representative system and guided by comparative evaluation of device-level contact interfaces, we translate Mg<sub>2</sub>Ni into a scale-bridging interfacial phase in n-type Mg<sub>3</sub>(Sb, Bi)<sub>2</sub>: it forms low-resistance and thermally stable external junctions while, as an internal interfacial modifier, alleviating grain-boundary carrier scattering and strengthening phonon scattering. This scale-bridged interface design yields an average zT of 1.5 over 300 to 723 K with high thermal stability. By applying Mg<sub>2</sub>Ni as both an internal modifier and an external barrier layer, a two-pair module delivers a stable conversion efficiency of 8.3% when coupled with p-type MgAgSb, comparing favorably with representative Bi<sub>2</sub>Te<sub>3</sub>-based thermoelectric modules in terms of conversion efficiency under comparable temperature differences. This work establishes a bridging interface design framework that links device contact engineering with internal interface modulation, providing a practical route toward efficient and durable thermoelectric energy conversion.