Thermoelectric properties of Ag-doped compound: Mg3-xAgxSb2

Abstract

Mg3Sb2-based thermoelectric materials have poor electrical conductivity which is the key to limit thermoelectric performance that need to be solved. Herein we tuned the carrier concentration of Mg3Sb2-based materials via Ag doping at the Mg sites (at two distinct crystallographic sites) to enhance the electrical performance. Mg3-xAgxSb2 (0 ≤ x ≤ 0.05) has been prepared successfully by vacuum suspension smelting plus Spark Plasma Sintering technique. Using the vacuum suspension smelting plus Spark Plasma Sintering method, we proved that Ag doping can precisely tune the electrical transport properties and accordingly enhance the power factor. Moreover, the Ag doping leads to a low lattice thermal conductivity due to phonons scattering, and the maximal thermoelectric figure of merit ZT for Mg2.96Ag0.04Sb2 reaches 0.66 at 773 K