AgSbTe₂-based ternary chalcogenides show excellent thermoelectric performance at low- and middle-temperature ranges, yet their practical applications are greatly limited by their intrinsic poor thermodynamic stability. In this work, we demonstrate that AgSbTe₂-based ternary chalcogenides can be stabilized for service below their decomposition threshold. A series of Ag_xSb_2-xTe_3-x (x = 1.0, 0.9, 0.8 and 0.7) samples have been prepared by the melt-quenching method. Among them, phase pure Ag_0.9Sb_1.1Te_2.1 is verified by comprehensive structural characterizations from macroscale by X-ray diffraction to microscale by energy-dispersive spectroscopy and then to sub-nanometer scale by atom probe tomography. This composition is further chosen for the stability investigation. The decomposition threshold of Ag_0.9Sb_1.1Te_2.1 appears around 473 K. Below this temperature, the chemical compositions and thermoelectric properties are barely changed even after 720 h annealing at 473 K. The figure-of-merit (zT) value of Ag_0.9Sb_1.1Te_2.1 below the decomposition threshold is very competitive for real applications even compared with Bi₂Te₃-based alloys. The average zT of Ag_0.9Sb_1.1Te_2.1 at 300–473 K reaches 0.84, which is higher than most other thermoelectric materials in a similar temperature range, promising applications in miniaturized refrigeration and power generation near room temperature.

AgSbTe ₂基三元硫属化物在低温和中温范围内表现出优异的热电性能，但其实际应用受到其固有的热力学稳定性差的极大限制。在这项工作中，我们证明了基于 AgSbTe ₂的三元硫属化物可以在低于其分解阈值的情况下稳定使用。 采用熔融淬火法制备了一系列Ag _x Sb _{2- x} Te _{3- x} ( x = 1.0, 0.9, 0.8 和0.7) 样品。其中，相纯 Ag _0.9 Sb _1.1 Te _2.1通过从 X 射线衍射的宏观尺度到能量色散光谱的微观尺度再到原子探针断层扫描的亚纳米尺度的综合结构表征来验证。该组合物被进一步选择用于稳定性研究。Ag _0.9 Sb _1.1 Te _2.1的分解阈值出现在 473 K 左右。低于此温度，即使在 473 K 退火 720 小时后，化学成分和热电性能也几乎没有变化。Ag _{0.9的品质因数 (} zT ) 值即使与 Bi ₂ Te ₃相比，低于分解阈值的Sb _1.1 Te _{2.1在实际应用中也极具竞争力}基合金。Ag _0.9 Sb _1.1 Te _2.1在300-473 K的平均zT达到0.84，高于同类温度范围内的大多数其他热电材料，有望在室温附近的小型制冷和发电中得到应用。