PREPARATION AND THERMOELECTRIC PROPERTIES OF p-TYPE Ag(1-x)Cu(1+x)Te SAMPLES BY SPARK PLASMA SINTERING METHOD

Abstract

The combination of silver (Ag), copper (Cu), and telluride (Te) yields silver copper telluride (AgCuTe), a new type of ternary liquid-like thermoelectric material. Due to its ultra-low lattice thermal conductivity and highly symmetrical cubic crystal structure, it exhibits excellent thermoelectric properties in the medium-to-high temperature range (400-600 K). However, hexagonal crystal structures with lower symmetry near room temperature can lead to higher thermal conductivity. In addition, the high carrier concentration of the hexagonal crystal structure results in a lower Seebeck coefficient for the material. This seriously affects the application of AgCuTe-based thermoelectric materials in the room temperature range. Therefore, how to improve the thermoelectric performance of AgCuTe-based thermoelectric materials in the room temperature range has received widespread attention from researchers. AgCuTe-based thermoelectric materials were successfully prepared by mechanically alloying Ag, Cu, and Te powders using a planetary ball mill combined with spark plasma sintering. On this basis, the thermoelectric properties of AgCuTe-based materials were optimized by adjusting the Ag/Cu ratio and Ag<sub>2</sub>Te/CuTe content. The results indicated that at 600 K, the Ag<sub>0.93</sub>Cu<sub>1.07</sub>Te sample obtained a high Seebeck coefficient value of approximately 171 μV/K<sup>-1</sup>. Finally, the ZT peak obtained from the Ag<sub>093</sub>Cu<sub>1.07</sub>Te sample was 1.06; compared with AgCuTe (ZT = 0.78), it had increased by about 36%.