摘要
Cu-and Ag-based superionic conductors are promising thermoelectric materials due to their good electrical properties and intrinsically low thermal conductivity. However, the poor electrical and thermal stability restrict their application. In this work, n-type pure phase Ag_(2) Te compound is synthesized by simply grinding elemental powders at room temperature and compacted by spark plasma sintering. It is found that, because of the migration of Ag+after the phase transition around 425 K, submicron pores are formed inside the samples during the electrical performance measurement, resulting in poor electrical stability and repeatability of Ag_(2) Te samples. However, Pb-doped Ag_(2-x)Pb_(x)Te(x = 0–0.05) specimens exhibit improved electrical stability by the precipitation of the secondary phase Pb Te in the Ag_(2) Te matrix, which is confirmed via cyclic electrical property measurement and microstructure characterization.A maximum z T = 0.72 is obtained at 570 K for x = 0.03 mainly due to the increased power factor.
基金
financially supported by the National Science Fund for Distinguished Young Scholars (No. 51725102)
the Natural Science Foundation of China (Nos. 51871199, 51861145305)。
