Effective Diffusion Barrier Layer Achieves Thermal Stability for n-Type Bi₂Te_2.7Se_0.3 Thermoelectric Generators

Area of Science:

• Materials Science
• Solid State Physics
• Energy Conversion

Background:

• Bismuth telluride (Bi2Te3) alloys are crucial for commercial thermoelectric power generation near room temperature.
• Improving the performance and long-term stability of n-type Bi2Te3 devices is essential for advanced applications.
• Interfacial diffusion between thermoelectric materials and electrodes can degrade device performance.

Purpose of the Study:

• To investigate metal barrier materials for n-type Bi2Te3 thermoelectric devices.
• To understand the diffusion behavior of 11 metals in n-type Bi2Te2.7Se0.3.
• To enhance the stability and power generation capability of thermoelectric devices.

Main Methods:

• Diffusion behavior analysis of 11 metals in n-type Bi2Te2.7Se0.3.
• Identification of promising barrier materials based on bonding and diffusion coefficients.
• Fabrication of single-leg devices and modules using Ti as a barrier layer with Ni electrodes.

Main Results:

• Titanium (Ti) exhibited excellent bonding with Bi2Te2.7Se0.3 sintered at low temperatures and showed a low diffusion coefficient.
• Devices fabricated with Ti as a barrier layer demonstrated stable output power and conversion efficiency.
• The Ti barrier layer ensured excellent thermal stability for thermoelectric generators operating at 495 K for 160 hours.

Conclusions:

• Titanium is a highly effective barrier material for n-type Bi2Te3 thermoelectric devices, preventing interfacial diffusion.
• The use of Ti significantly enhances the thermal stability and long-term reliability of thermoelectric power generators.
• This finding paves the way for more robust and efficient thermoelectric power generation applications.