SnTe is a lead-free and promising mid-temperature thermoelectric material while its performance is largely hindered owing to the relatively high hole carrier concentration originating from the existence of extraordinary Sn vacancies in intrinsic SnTe. In this study, we firstly introduced excess Pb into SnTe matrix to compensate the Sn vacancies, leading to the greatly decreased carrier concentration. Then, we found that the ternary compound AgSbTe₂ plays synergistic roles in optimizing the thermoelectric transport properties of SnTe. Namely, alloying AgSbTe₂ can induce the electronic band convergence and band flattening in SnTe, leading to the significantly enhanced band effective mass (m∗) and Seebeck coefficient. Additionally, alloying AgSbTe₂ produces plentiful Ag-rich nanoprecipitates, which strengthens the scattering of phonons, leading to the lowest lattice thermal conductivity of ∼0.47 Wm⁻¹K⁻¹. By this stepwise strategy, an outstanding ZT value ∼1.1 can be attained at 823 K for the SnPb_0.04Te–12%AgSbTe₂ sample, while an average ZT can be obtained ∼ 0.72 from 400 K to 800 K for sample SnPb_0.04Te-12%AgSbTe₂. Our study further reveals the great potential for SnTe as promising thermoelectrics.

SnTe 是一种无铅且有前途的中温热电材料，但由于本征 SnTe 中存在异常的 Sn 空位导致相对较高的空穴载流子浓度，其性能在很大程度上受到阻碍。在这项研究中，我们首先将过量的 Pb 引入 SnTe 基体以补偿 Sn 空位，导致载流子浓度大大降低。然后，我们发现三元化合物 AgSbTe ₂在优化 SnTe 的热电传输性能方面发挥协同作用。即，合金化 AgSbTe ₂可以诱导SnTe 中的电子能带收敛和能带平坦化，导致显着增强的能带有效质量 ( m *) 和塞贝克系数。此外，合金化 AgSbTe ₂产生大量富含 Ag 的纳米沉淀物，这增强了声子的散射，导致最低的晶格热导率约为 0.47 Wm ^-1 K ^-1。通过这种逐步策略，SnPb _0.04 Te–12%AgSbTe ₂样品在 823 K 时可达到优异的ZT值 ~1.1 ，而 样品 SnPb _0.04 Te-在 400 K 至 800 K 下的平均 ZT 值可达到 ~ 0.72 12%AgSbTe ₂。我们的研究进一步揭示了 SnTe 作为有前途的热电材料的巨大潜力。