A high performance eco-friendly MgAgSb-based thermoelectric power generation device near phase transition temperatures

Abstract

The utilization of thermoelectric (TE) technology for eco-friendly energy harvesting presents a promising solution for off-grid power generation from waste heat. Despite the dominance of Bi₂Te₃ TE devices in the current market, their widespread application is hindered by the scarcity of Te and the fragile electrode contact interface. In this study, we introduce a novel thermoelectric interface material (TEiM), AgMgMn_0.1, for the MgAgSb TE material, utilizing a multi-element alloying approach. This results in an advanced interface with a high bonding strength of 34.5 MPa and a low contact resistivity of 4.5 μΩ cm², thereby overcoming the phase transition stress. In situ microstructure characterization and simulation demonstrate robust stability near phase transition temperatures and a low maximum von Mises stress, respectively. Additionally, we achieved a high performance MgAgSb-based device, with a maximum conversion efficiency of 9.1% at a temperature difference of 325 °C. These values surpass those of commercial Bi₂Te₃ products at low-grade temperature ranges. Eco-friendly MgAgSb-based Te-free TE devices offer a reliable solution for waste heat harvesting.