Decoupling Charge-Phonon Transport via Hierarchical Interface Reconstruction in Skutterudite Thermoelectrics

Abstract

A central challenge in thermoelectric science is to break the intrinsic coupling between charge and heat transport. Herein, we demonstrate that thermally driven interface reconstruction in perovskite-modified skutterudites generates a hierarchical defect architecture that enables simultaneous regulation of electronic and phononic transport. By deliberately integrating point defects, (Pb, In)-rich nanoprecipitates, and multiscale pores into a unified interfacial framework, the reconstructed microstructure enhances carrier-energy selectivity while fostering broadband phonon scattering across multiple length scales. This synergy effectively mitigates the conventional electrical–thermal trade-off, yielding a peak zT of ∼1.76 at 773 K. A seven-couple thermoelectric generator assembled from the optimized material delivers a conversion efficiency of 8.1% under a temperature difference of 452 K. Collectively, these findings establish hierarchical interface reconstruction as a powerful strategy for transport decoupling and highlight defect-architecture engineering as a versatile design principle for thermoelectric energy conversion.