Enhancing Near-Room-Temperature Thermoelectric Performance of n-Type Mg₃(Sb, Bi)₂-Based Materials via ZrB₂...

Area of Science:

• Materials Science
• Thermoelectric Materials
• Nanocomposites

Background:

• Mg3(Sb, Bi)2-based materials show promise for low-grade waste heat recovery.
• Thermoelectric performance is limited by the coupled electrical and thermal transport properties.
• Need for strategies to optimize carrier transport and phonon scattering.

Purpose of the Study:

• To enhance the thermoelectric performance of Mg3(Sb, Bi)2 by introducing a conductive ceramic composite strategy.
• To investigate the effect of zirconium diboride (ZrB2) heterointerfaces on charge distribution and carrier transport.
• To achieve synergistic regulation of interfacial charge, carrier transport, and phonon scattering.

Main Methods:

• First-principles calculations to understand interfacial charge redistribution and electric field generation.
• Fabrication of Mg3.4Bi1.29Sb0.7Te0.01 matrix composites with varying wt.% of ZrB2.
• Experimental characterization of structural, electrical, and thermal transport properties.

Main Results:

• ZrB2 incorporation creates stable heterointerfaces, driving interfacial charge redistribution and a localized built-in electric field.
• The 1.0 wt.% ZrB2 composite shows significantly increased carrier concentration and electrical conductivity, with maintained carrier mobility.
• A maximum ZT value of 1.22 at 573 K and a conversion efficiency of 12.92% were achieved, demonstrating enhanced thermoelectric performance.

Conclusions:

• Conductive ceramic heterointerface engineering is an effective strategy for improving Mg3(Sb, Bi)2-based thermoelectric materials.
• ZrB2 addition synergistically optimizes carrier transport and phonon scattering, leading to superior thermoelectric properties.
• The developed composite materials show high potential for efficient low-grade waste heat recovery applications.