Robust bendable thermoelectric generators enabled by elasticity strengthening.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Energy Harvesting

Background:

• Thermoelectric generators (TEGs) offer continuous power for wearable electronics using body heat.
• Inorganic TEGs, while efficient, lack the flexibility required for wearable applications due to material rigidity.
• Achieving recoverable flexibility in high-performance thermoelectrics is crucial for seamless integration into wearable devices.

Purpose of the Study:

• To develop highly elastic and recoverable inorganic thermoelectric generators for continuous wearable power.
• To engineer the microstructure of silver selenide (Ag2Se) to enhance its elasticity and bending performance.
• To demonstrate a viable strategy for creating robust, flexible TEGs for diverse body-worn applications.

Main Methods:

• Microstructure engineering of Ag2Se through a multi-pass hot-rolling technique.
• Inducing dense dislocations and refining grain structures to improve material elasticity.
• Fabricating thin thermoelectric generators capable of large elastic strain and recoverable bending.

Main Results:

• Achieved a record-breaking bendability of over 1,000,000 cycles at a 3 mm bending radius.
• Demonstrated full recoverability of thermoelectric performance after extensive bending.
• Exhibited extraordinary power density in the elastic thin thermoelectric generators.
• Engineered Ag2Se exhibits significantly enhanced elasticity due to microstructure modifications.

Conclusions:

• Microstructure engineering of Ag2Se via hot rolling provides a promising route to highly flexible inorganic thermoelectrics.
• The developed elastic thin thermoelectric generators are suitable for curved surfaces on the human body.
• This work presents a significant advancement for powerful and durable inorganic wearable thermoelectric devices.