Ultrahigh thermoelectricity obtained in classical BiSbTe alloy processed under super-gravity

Area of Science:

• Materials Science
• Solid State Physics
• Energy Conversion

Background:

• Thermoelectric materials convert heat to electricity, enabling power generation and solid-state refrigeration.
• Improving thermoelectric performance is hindered by the complex interplay between electrical and thermal transport properties.
• Optimizing thermoelectric materials requires innovative fabrication techniques to overcome inherent material limitations.

Purpose of the Study:

• To introduce a novel super-gravity-field re-melting fabrication technology.
• To synergistically optimize the thermoelectric performance of (Bi,Sb)2Te3 alloys.
• To demonstrate a new strategy for enhancing thermoelectric materials applicable to other systems.

Main Methods:

• Utilizing a super-gravity field during the re-melting process of (Bi,Sb)2Te3 alloy.
• Inducing unusual plastic deformation and microstructure defects via super-gravity.
• Analyzing microstructure reconstruction and carrier concentration optimization.

Main Results:

• Achieved ultra-low lattice thermal conductivity (<0.25 W/m K).
• Obtained a record-high figure of merit (>1.91) for BiSbTe alloy.
• Demonstrated a thermoelectric module with 6.4% conversion efficiency and 0.34 W/cm2 output power density at 185 K temperature difference.

Conclusions:

• The super-gravity fabrication method significantly enhances thermoelectric properties by optimizing microstructure and carrier concentration.
• This novel approach offers a promising strategy for advancing thermoelectric materials for efficient energy conversion.
• The demonstrated technology has potential applications in various thermoelectric materials and devices.