Superior performance and high service stability for GeTe-based thermoelectric compounds.

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectric Materials

Background:

• GeTe-based compounds show promise for thermoelectric applications.
• Limited applications due to volume variation during phase transitions causing material failure.

Purpose of the Study:

• To improve the performance and service stability of GeTe-based thermoelectric materials.
• To address the challenge of volume variation during the rhombohedral-cubic phase transition.

Main Methods:

• Co-doping GeTe with Magnesium (Mg) and Antimony (Sb).
• Tuning carrier concentration and suppressing lattice thermal conductivity.
• Fabricating and testing a Ni/Ti/Ge0.85Mg0.05Sb0.1Te thermoelectric uni-leg.

Main Results:

• Achieved a smooth volume variation around the phase transition temperature by improving the linear coefficient of thermal expansion.
• Reached a peak figure of merit (zT) of 1.84 at 800 K and an average zT of 1.2 from 300-800 K.
• Demonstrated excellent service stability over 450 thermal cycles between 473 K and 800 K.

Conclusions:

• Co-doping Mg and Sb in GeTe significantly enhances thermoelectric performance and stability.
• The developed material is suitable for mid-temperature power generation applications.
• This research paves the way for practical applications of GeTe-based thermoelectrics.