Synergistic Enhancement of Mechanical and Thermoelectric Properties in Ag2Te through Si Nanoinclusions

Abstract Ag2Te is a promising thermoelectric material for near room temperature applications. In this study, we successfully synthesized Ag2Te and Ag2Te–X Si (X = 2–5 wt %) nanocomposites by incorporating elemental silicon into the Ag2Te matrix through mechanical alloying. The effect of Si incorporation on the thermoelectric properties was systematically investigated from 300 to 600 K. The thermoelectric performance of the resultant nanocomposite materials was significantly improved by the addition of Si. This improvement is mainly attributed to interface-driven energy filtering and increased phonon scattering at the Si/Ag2Te interfaces. These effects resulted in an increase in the power factor to 1511.5 μW/m K2 and a reduction in the thermal conductivity to 0.92 W/m K at 300 K for the Ag2Te –4.5 wt % Si nanocomposite. As a result, an improved thermoelectric figure of merit (ZT) of ~0.48 at 300 K was achieved, which is ~49% higher than that of pure Ag2Te (ZT ~ 0.32). This is one of the highest reported values for Ag2Te at room temperature. Additionally, the nanocomposite showed an improved average ZT of ~0.35 over the temperature range of 300–600 K. This work presents an effective second phase engineering strategy for enhancing the thermoelectric properties of n-type Ag2Te alloys for near room-temperature applications. Furthermore, notable improvements in the mechanical properties of the composite sample were observed.