Fast preparation of AgxPb20SbTe20 (x = 0.5–3) component with high thermoelectric performance

Abstract

PbTe-based quaternary AgPbmSbTem+2 (LAST) has been a kind of promising thermoelectric materials due to its relatively low lattice thermal conductivity and good electrical performance. However, traditional melting or mechanical alloying methods are time-consuming, which is not suitable for applications. To solve this problem, a fast method combined self-propagating high-temperature synthesis (SHS) with spark plasma sintering (SPS) has been adopted in this work. Nanostructured n-type AgxPb20SbTe20 (x = 0.5–3) materials with high thermoelectric performance have been successfully prepared. On one hand, power factors of all samples reached over 1.6 mW·m−1·K−2 at high temperature, because Ag assembles grain boundaries and forms Ag2Te precipitates in the SHS process, enhancing the thermoelectric properties by modulation doping, energy filtering and dynamic doping. On the other hand, the Ag2Te-PbTe coherent interfaces bring multiple phonon scattering resources to reduce the thermal conductivity. As a result, a high ZT value of ∼1.32 at 773 K is achieved in Ag1.25Pb20SbTe20. This work provides a facile, rapid and energy-saving way to prepare PbTe-based materials with good thermoelectric performance.