Abstract: The intensification of energy crises and environmental pollution inspire researchers' attention to environment-friendly SnTe thermoelectric materials. In this work, we achieved a lower lattice thermal conductivity and optimized the power factor via the synergistic optimization of bonding characteristic, V_Sn, and resonant level for the SnTe system, respectively. Pb-introduction produces weak bonding strength, mass fluctuation, and stress distortion, which result in lower thermal conductivity. The lowest lattice thermal conductivity achieves 0.66 W m^-1 K^-1 at 773 K. Further introduced V_Sn relieves loss of electrical conductivity caused by Pb-introduction, and it also makes the bigger g(E) and up-shift of resonance level. The V_Sn, enhanced g(E), and resonant level make electrical conductivity and Seebeck coefficient enhance simultaneously. Finally, the further optimization of thermal and electronic transport performance contributes to a higher ZT value of ∼0.86 at 773 K in the Sn_0.685Pb_0.285In_0.015Te_0.7Se_0.3 sample. The strategy of bonding characteristic, V_Sn, and resonant level synergistic engineering will be widely applicable to various TE systems for achieving better thermoelectric performance.

Key words: SnTe-based material, Low thermal conductivity, Projected crystal orbital hamiltonian populations, V_Sn, Resonant level