Flexible Thermoelectric Belt: Enabling Recyclable Wearables for Self-Powered Gesture Recognition

Area of Science:

• Materials Science
• Energy Harvesting
• Wearable Technology

Background:

• Flexible thermoelectric generators (f-TEGs) are crucial for powering wearable electronics using low-grade waste heat.
• Existing f-TEGs often face challenges with complex fabrication and limited durability.

Purpose of the Study:

• To develop a robust, recyclable f-TEG for self-powered wearable systems.
• To enhance thermal conductivity and mechanical stability of the f-TEG.
• To demonstrate the f-TEG's capability in powering an intelligent posture recognition system.

Main Methods:

• Fabrication of an f-TEG using Bi2Te2.7Se0.3 (n-type) and Bi0.5Sb1.5Te3 (p-type) thermoelectric materials with liquid metal electrodes.
• Encapsulation of the f-TEG using a polydimethylsiloxane (PDMS) composite with aluminum nitride (AlN) nanoparticles to improve thermal conductivity.
• Integration of the f-TEG into a wearable belt and testing its performance in powering a depthwise separable GRU network (DSGNet) for posture recognition.

Main Results:

• The PDMS composite achieved a thermal conductivity of 0.45 W m⁻¹ K⁻¹, thrice that of pure PDMS.
• The f-TEG demonstrated excellent mechanical and electrical stability, withstanding 10,000 h of cyclic reorientation and 100,000 cycles of dynamic twisting.
• The integrated system, powered by body heat, delivered 180.6 mV and achieved 98.96% posture recognition accuracy using the DSGNet.
• Thermoelectric materials and liquid metal were successfully recovered and reused non-destructively.

Conclusions:

• The developed f-TEG offers a sustainable and efficient solution for harvesting body heat to power wearable electronics.
• The device's robustness, recyclability, and high performance pave the way for self-powered intelligent human body protection systems.
• This work highlights a feasible manufacturing pathway for long-lasting and easily producible self-powered wearable systems.