High-Performance Thermoelectric Bulk Colusite by Process Controlled Structural Disordering

Area of Science:

• Materials Science
• Solid State Physics
• Inorganic Chemistry

Background:

• Thermoelectric materials convert heat to electricity, crucial for energy harvesting.
• Colusite sulfides (Cu26V2Sn6S32) show potential but require optimization for efficiency.
• Achieving high thermoelectric performance necessitates simultaneously optimizing electrical and thermal transport properties.

Purpose of the Study:

• To engineer high-performance thermoelectric bulk sulfides with the colusite structure.
• To elucidate the mechanism behind intrinsically low thermal conductivity in colusites.
• To demonstrate a scalable method for enhancing thermoelectric properties through defect engineering.

Main Methods:

• Controlled densification processes to introduce structural defects.
• Point defect and disordered region engineering for phonon scattering.
• Experimental characterization combined with band structure and phonon calculations.
• Analysis of sulfur vacancies and antisite defects' impact on carrier concentration.

Main Results:

• Achieved high-performance thermoelectric bulk sulfides with the colusite structure.
• Demonstrated enhanced phonon scattering via point defects and disordered regions.
• Elucidated the intrinsic low thermal conductivity mechanism in colusite samples.
• Identified the effect of S vacancies and antisite defects on carrier concentration.
• Engineered high power factors and figures of merit near unity.

Conclusions:

• Controlling the densification process and structural defects is key to high-performance thermoelectric colusites.
• Point defects and disordered regions effectively enhance phonon scattering, reducing thermal conductivity.
• The developed method offers a controlled and scalable route to optimize complex bulk sulfides for thermoelectric applications.