Band Engineering and Phonon Engineering Effectively Improve n-Type Mg₃Sb₂ Thermoelectric Material Properties

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectrics

Background:

• Mg3Sb2-based materials are promising for thermoelectric applications, converting heat to electricity.
• Improving electrical performance and reducing thermal conductivity are key challenges.
• Zintl phases offer a route to advanced thermoelectric materials.

Purpose of the Study:

• To design and investigate a novel thermoelectric Zintl phase based on Mg3.2Sb1.5Bi0.5.
• To enhance thermoelectric performance through codoping with Terbium (Tb) and Erbium (Er).
• To evaluate the impact of codoping on electrical properties, thermal conductivity, and mechanical stability.

Main Methods:

• Utilized oneness principle calculations for material design.
• Synthesized Mg3.2Sb1.5Bi0.5 doped with Tb and Er.
• Conducted experimental characterization of thermoelectric properties (ZT value, power factor).
• Measured mechanical properties including Young's modulus and Vickers hardness.

Main Results:

• Codoping with Tb and Er effectively improved electrical properties and reduced lattice thermal conductivity.
• The Mg3.185Tb0.01Er0.005Sb1.5Bi0.5 sample achieved a maximum ZT value of 1.71.
• The material exhibited good mechanical properties (Young's modulus: 51.85 GPa, Vickers hardness: 0.99 GPa).
• Demonstrated stable performance with low power factor error (1.8%-2.1%) over 12 thermal cycles (323-723 K).

Conclusions:

• Codoping Mg3Sb2-based Zintl phases with Tb and Er is an effective strategy to enhance thermoelectric performance.
• The designed material shows significant potential for practical thermoelectric device applications due to its high ZT value and stability.
• This research contributes to the development of efficient and environmentally friendly thermoelectric materials.