Fine-Grained and Nanostructured AgPbmSbTem+2 Alloys with High Thermoelectric Figure of Merit at Medium Temperature

摘要

AgPbmSbTem+2 (abbreviated as LAST) has received tremendous attention as a promising thermoelectric material at medium temperature. It can be synthesized by a simple process combining mechanical alloying (MA) and spark plasma sintering (SPS). This work reveals that the thermoelectric figure of merit (ZT value) of LAST can be increased by 50%, benefiting from enhanced electrical conductivity and thermopower due to refined grains and from nanostructuring realized by repeating the milling and SPS processes. This modified process and further compositional optimization enables ZT values of the LAST alloys up to 1.54 at 723 K. This supports the potential of the LAST alloy as a promising medium-temperature thermoelectric material and reveals the validity of ZT enhancement by a simple microstructural refining and nanostructuring method.