High Conversion Efficiency in Intrinsic High Power-Density Mg₂Sn-GeTe Thermoelectric Generator

Area of Science:

• Materials Science
• Energy Harvesting
• Solid-State Physics

Background:

• Thermoelectric generators (TEGs) are crucial for sustainable thermal energy harvesting.
• High power density TEGs often suffer from low conversion efficiency due to high thermal conductivity.
• Optimizing both power density and efficiency is key for advanced TEG applications.

Purpose of the Study:

• To develop novel thermoelectric generators (TEGs) with simultaneously high power density and conversion efficiency.
• To introduce Mg2Sn-GeTe based TEGs as a new benchmark in thermoelectric performance.
• To explore strategies for balancing carrier and phonon transport in thermoelectric materials.

Main Methods:

• Fabrication of Mg2Sn-GeTe thermoelectric materials.
• Incorporation of stepwise aliovalent Sb and Bi solid solutions into Mg2Sn.
• Characterization of thermoelectric properties including power factor, thermal conductivity, and conversion efficiency.

Main Results:

• Achieved a remarkable 9% conversion efficiency in Mg2Sn-GeTe TEGs under a 418 K temperature gradient.
• Set a new benchmark for intrinsically high power density TEGs.
• Obtained a high thermoelectric figure of merit (zT) of 1.4 in Mg2Sn0.8(Sb0.5Bi0.5)0.2.
• Demonstrated a balanced carrier and phonon transport through aliovalent doping.

Conclusions:

• Mg2Sn-GeTe TEGs represent a significant advancement in thermoelectric technology.
• The developed TEGs offer an innovative and efficient solution for off-grid energy supply.
• This work highlights the potential of Mg2Sn-based materials for high-performance thermoelectric applications.