The effects of Ag nanoparticles on the thermoelectric properties of Ag₂Te-Ag composite fabricated using an energy-saving route

We measure electricity consumption and thermoelectric property of Ag₂Te-Ag composites fabricated using green synthesis at room temperature followed by evacuated-and-encapsulated sintering at 500 °C for 10 h. As compared to Ag₂Te and Ag₂Te-Ag composites fabricated using other methods, we elucidate the effects of Ag nanoparticles on electronic transport of composites at temperatures between structural transition and 525 K based on the Matthiessen's rule and Kohler formula. We also present detailed methods of calculating the Lorenz number with single Kane band model and further deduce the lattice thermal conductivity. As a result, we find that electronic contribution dominates the temperature dependence of the total thermal conductivity of the composites. For energy consumption of heat treatment, the energy-saving approach in this study is only 15–18% of two typical procedures using melting process reported in the literature. If considering consolidation step reported in the literature, our procedure is more economic. We also demonstrate that the energy-saving route of fabricating the Ag₂Te-Ag composite leads to a zT value of 0.68 at 573 K, which is comparable to or even higher than that of Ag₂Te fabricated using high-energy consumption routes. It is more sensible for fabricating TE materials using less energy consumption.