Three-dimensional flexible thermoelectric fabrics for smart wearables

Wearable thermoelectric devices, capable of converting body heat into electrical energy, provide the potential driving power for the Internet of Things, artificial intelligence, and soft robotics. However, critical parameters have long been overlooked for these practical applications. Here, we report a three-dimensional flexible thermoelectric device with a structure featuring an inner rigid and outer flexible woven design. Such a structure includes numerous small static air pockets that create a stable out-of-plane temperature difference, enabling precise temperature signal detection (accuracy up to 0.02 K). Particularly, this structure exhibits excellent multi-signal decoupling capability, excellent elasticity (>10,000 compression cycles), ultra-fast compression response (20 ms), stable output signal under 50% compressive strain, high breathability (1300 mm s^-1), and washability. All these metrics achieve the highest values currently reported, fully meeting the requirements for body heat and moisture exchange, as demonstrated in our designed integrated smart mask and smart glove systems based on vector machine learning technology. This work shows that our three-dimensional flexible thermoelectric device has broad applicability in wearable electronics.