Stretchable thermoelectric generators with enhanced output by infrared reflection for wearable application

Flexible thermoelectric generators can directly convert body heat into electricity to power wearable electronics, which is recognized as a potential candidate for durable energy supply. Nevertheless, the parasitic heat loss and inadequate waterproofing have greatly limited its practical application. Here we propose a compliant engineering solution for encapsulated thermoelectric generators that ensures sufficient alignment of thermal gradient based on infrared reflection effect, which realized both the increased infrared radiation insulation at hot end and the reduced radiation heating of cold end. It contributes to a remarkable increase in temperature difference as compared to the unencapsulated one when subjected to a same heat source, presenting up to ∼35% increase in voltage output. Owing to waterproof encapsulation, this TE wristband is reliable in a variety of real-life activities such as running and swimming. Moreover, the design concepts of thermoelectric wristband described here can bring new inspiration for realizing body energy harvesting.