In 1970s, great efforts had been spent to develop Ag-containing Cu₂Se-based radioisotope thermoelectric generators (RTG), but unfortunately the activity was completely stopped in 1981 because the Ag-containing Cu₂Se-based thermoelectric module demonstrated poor service stability. Since then, a prevailing mindset in thermoelectric society is that Cu₂Se, and related Cu-based thermoelectric materials, can not be fabricated into stable modules. In this study, a series of Ag-containing Cu₂Se samples are synthesized. Their thermoelectric properties and service stability under current and/or temperature gradient are systematically investigated. It is found that introducing Ag in Cu₂Se has significant influence on the thermoelectric properties but little influence on the stability. The critical voltages for Ag-containing Cu₂Se samples, which represent the threshold for thermodynamic stability under electric field and/or temperature gradient, are determined by the total content of Cu and Ag rather than just the Cu content. Likewise, electrical conductivity is proposed to be a simple indicator to rapidly predict the stability and thermoelectric performance of Cu₂Se-based materials. Based on the measured critical voltages, the rational ranges of leg geometry are recommended to fabricate the stable and efficient Cu_1.97Ag_0.03Se-based thermoelectric modules.

1970年代，曾大力开发含银Cu ₂ Se基放射性同位素热电发电机（RTG），但遗憾的是，由于含Ag Cu ₂ Se基热电模块的使用稳定性差，该活动在1981年完全停止. 从那时起，热电社会的普遍心态是，无法将Cu ₂ Se 和相关的铜基热电材料制成稳定的模块。在本研究中，合成了一系列含 Ag 的 Cu ₂ Se 样品。系统地研究了它们在电流和/或温度梯度下的热电性能和使用稳定性。发现在Cu ₂中引入AgSe对热电性能有显着影响，但对稳定性影响不大。含 Ag 的 Cu ₂ Se 样品的临界电压代表电场和/或温度梯度下热力学稳定性的阈值，由 Cu 和 Ag 的总含量决定，而不仅仅是 Cu 含量。同样，电导率被认为是一个简单的指标，可以快速预测 Cu ₂ Se 基材料的稳定性和热电性能。根据测得的临界电压，推荐合理的腿几何范围来制造稳定高效的 Cu _1.97 Ag _0.03 Se 基热电模块。