High-performance Mg3Sb2-based thermoelectrics with reduced structural disorder and microstructure evolution
Longquan Wang1,2, Wenhao Zhang1, Song Yi Back1
1Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan.
Nature Communications
|August 9, 2024
Summary
Indium doping and extended sintering optimize Mg3Sb2 thermoelectrics by reducing defects. This enhances thermoelectric performance, achieving a high figure of merit (zT) for efficient power generation and cooling applications.
Area of Science:
- Materials Science
- Solid State Physics
- Thermoelectrics
Background:
- Magnesium antimonide (Mg3Sb2)-based materials are promising for thermoelectric devices due to their earth-abundant elements and high figure of merit (zT).
- The performance of Mg3Sb2 is currently limited by complex defect microstructures that hinder optimal electron and phonon transport.
Purpose of the Study:
- To improve the thermoelectric performance of Mg3Sb2 materials by modifying their defect microstructure.
- To investigate the effects of Indium (In) doping and prolonged sintering on structural disorder and microstructural evolution.
- To synergistically optimize electron and phonon transport through a delocalization effect.
Main Methods:
- Mg3Sb2 materials were doped with Indium (In).
- Samples underwent prolonged sintering processes.
- Microstructure, carrier mobility, thermal conductivity, and thermoelectric figure of merit (zT) were analyzed.
Main Results:
- Reduced structural disorder and controlled microstructural evolution were achieved.
- An excellent carrier mobility of ~174 cm^2 V^-1 s^-1 and an ultralow thermal conductivity of ~0.42 W m^-1 K^-1 were obtained.
- An ultrahigh figure of merit (zT) of ~2.0 at 723 K was realized, with single-leg and two-pair modules showing high conversion efficiencies of 12.6% and 7.1%, respectively.
Conclusions:
- The study demonstrates a successful strategy to enhance Mg3Sb2 thermoelectric performance via In doping and optimized sintering.
- The achieved results represent a significant advancement for the practical application of Mg3Sb2-based thermoelectric generators and coolers.
