Robust Homogeneous Segmented Power Generator Driven by Sb₂Te₃-Based Thermoelectrics.

Area of Science:

• Materials Science
• Solid State Physics
• Energy Conversion

Background:

• Thermoelectric (TE) technology is crucial for waste heat recovery, especially for low-grade heat (<650 K).
• Traditional Bi₂Te₃ alloys have limited TE efficiencies (<7%) and a narrow operating temperature range.
• There is a need for advanced TE materials with improved efficiency and mechanical properties for practical applications.

Purpose of the Study:

• To enhance the thermoelectric performance of Sb₂Te₃-based materials through doping.
• To investigate the effects of Cadmium (Cd) and Sulfur (S) doping on the microstructure and thermoelectric properties.
• To develop a high-efficiency thermoelectric power generator for low-grade waste heat harvesting.

Main Methods:

• Microstructural engineering via doping Sb₂Te₃ with Cd and S.
• Characterization of lattice thermal conductivity, density-of-states effective mass, and band gap.
• Fabrication and testing of a segmented thermoelectric power generator using optimized Bi-Sb-Te alloys.

Main Results:

• Doping with Cd and S reduced lattice thermal conductivity by 45% at 300 K.
• The Cd_0.04Sb_1.96Te_2.94S_0.06 sample achieved a peak figure of merit (ZT) of 1.1 at 650 K.
• A segmented TE power generator demonstrated a certified efficiency of 9.3% under a 350 K temperature gradient.
• The material exhibited excellent mechanical strength (197 MPa compressive, 56 MPa bending).

Conclusions:

• Cd and S doping effectively regulate the microstructure of Sb₂Te₃, enhancing thermoelectric properties.
• The developed materials show significant potential for efficient low-grade waste heat recovery.
• This research extends the operational temperature of Bi₂Te₃-based thermoelectrics and offers a viable path for practical TE power generation.