Realizing High Thermoelectric Performance in N-Type Mg3(Sb, Bi)2-Based Materials via Synergetic Mo Addition and Sb–Bi Ratio Refining

摘要

Developing thermoelectric (TE) performance is impeded by the compromiseof TE parameters, resulting in inadequate conversion efficiency of heat toelectricity. Herein, this work reports that Mo is a particularly effective additivein Mg_3Sb_2-based alloys with significantly improved electronic transport viagrain-boundary engineering and band-structure regulation synergy. Inaddition, phonon transport is simultaneously suppressed by employingmultiple effects, lattice imperfection scattering, reduced phonon groupvelocity, and enhanced atomic disorder, leading to a minimum lat = 0.52 Wm~(?1) K~(?1) at 723 K. As a result, an outstanding ZT peak of ≈1.84 at 723 K andZtav = 1.34 within 323–723 K are achieved in Mg_3Sb_2-based alloys, and thecorresponding fabricated single-leg TE module shows an exceptionally highconversion efficiency of ≈12 under a hot-side temperature of 450 ℃. Theseresults demonstrate the great potential for advancing mid-temperature heatharvesting in Mg_3Sb_2-based materials.