Facile Route to High-Performance SnTe-Based Thermoelectric Materials: Synergistic Regulation of Electrical and Thermal Transport by in Situ Chemical Reactions

In this work, a composite product of Mn-substituted SnTe, SnO₂ nanoparticles, and MnTe-supersaturated precipitates has been fabricated by a simple in situ reaction between SnTe and MnO₂ for the first time. Benefiting from the synergistic effect induced by the product of in situ reaction, a remarkable improvement in the thermoelectric performance has been achieved. On the one hand, Mn substitution in SnTe can effectively modify the band structure and enhance the electrical properties of SnTe; on the other hand, the thermal transport can also be dramatically suppressed by in situ reaction-derived multiscale phonon scattering by point defects, SnO₂ nanoparticles, and supersaturated MnTe precipitates. Ultimately, a maximum ZT of ∼1.5 at 873 K has been achieved in the SnTe + 10 mol % MnO₂ sample, which increases by 224% in comparison with the pristine SnTe, representing one of the best results ever reported for SnTe-based thermoelectric materials.