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

Developing thermoelectric (TE) performance is impeded by the compromise of TE parameters, resulting in inadequate conversion efficiency of heat to electricity. Herein, this work reports that Mo is a particularly effective additive in Mg3Sb2-based alloys with significantly improved electronic transport via grain-boundary engineering and band-structure regulation synergy. In addition, phonon transport is simultaneously suppressed by employing multiple effects, lattice imperfection scattering, reduced phonon group velocity, and enhanced atomic disorder, leading to a minimum & kappa;(lat) = 0.52 W m(-1) K-1 at 723 K. As a result, an outstanding ZT peak of & AP;1.84 at 723 K and ZT(av) = 1.34 within 323-723 K are achieved in Mg3Sb2-based alloys, and the corresponding fabricated single-leg TE module shows an exceptionally high conversion efficiency of & AP;12% under a hot-side temperature of 450 & DEG;C. These results demonstrate the great potential for advancing mid-temperature heat harvesting in Mg3Sb2-based materials.