Effect of Ni Doping on Thermoelectric Properties of Ag2Te-Cu2Te Composite Material

Abstract Ag2Te is a potential thermoelectric material that has potential applications in the field of waste heat generation, with both “phonon-liquid electron-crystal” and superionic conductivity characteristics. However, the n-p-type conversion caused by phase transformation, as well as the bipolar effect resulting from a narrow energy gap, hinder the optimization of the dimensionless thermoelectric figure of merit (ZT). In this study, an Ag2Te-Cu2Te composite material was prepared by a solid-state method. The bipolar effect and n-p-type conversion of Ag2Te were inhibited by combining it with Cu2Te. High power factor was maintained, and the thermal conductivity was effectively reduced through Ni doping. Therefore, the ZT value increased, and reached 0.93 at 573 K, an increase of 41%, compared to the Ag2Te-Cu2Te without Ni doping.