Three-dimensional flexible thermoelectric fabrics for smart wearables

Area of Science:

• Materials Science
• Energy Harvesting
• Wearable Technology

Background:

• Wearable thermoelectric devices are crucial for powering the Internet of Things, AI, and soft robotics by converting body heat into electrical energy.
• Key performance parameters for practical applications of these devices have been previously overlooked.
• Existing devices often lack the necessary durability, responsiveness, and efficiency for widespread adoption.

Purpose of the Study:

• To develop a novel three-dimensional (3D) flexible thermoelectric device with enhanced performance metrics.
• To address critical overlooked parameters in wearable thermoelectric generators.
• To demonstrate the device's applicability in integrated smart systems.

Main Methods:

• Fabrication of a 3D flexible thermoelectric device with an inner rigid and outer flexible woven structure.
• Incorporation of static air pockets to create a stable out-of-plane temperature difference.
• Testing of device performance including temperature detection accuracy, elasticity, compression response, signal stability, breathability, and washability.

Main Results:

• Achieved precise temperature signal detection with accuracy up to 0.02 K.
• Demonstrated excellent elasticity (>10,000 compression cycles) and ultra-fast compression response (20 ms).
• Reported stable output signal under 50% compressive strain, high breathability (1300 mm s⁻¹), and washability, surpassing current benchmarks.
• Successfully integrated the device into smart mask and smart glove systems.

Conclusions:

• The developed 3D flexible thermoelectric device exhibits unprecedented performance in key metrics, meeting practical requirements for wearable applications.
• The device's unique structure facilitates efficient body heat harvesting and precise temperature sensing.
• This technology holds significant promise for broad applicability in next-generation wearable electronics and smart systems.