Stretchable Micro-Wrinkled Carbon Nanotube-Assembled Skin-Adhesive Patches with Suction-Cup Patterns for Human Breath-Derived Moisture Energy Harvesting

Abstract

With significant advances in self-powered, stretchable, and skin-attachable electronics, harvesting energy from ubiquitous moisture has emerged as a promising method for powering wearable and adhesive devices. However, current moisture energy harvesting (MEH) devices still face challenges in direct application to skin surfaces, mainly due to insufficient stretchability and weak adhesion, particularly under wet conditions. Here, we construct a stretchable and skin-adhesive MEH patch by harnessing microwrinkled carbon nanotube (CNT) sheets featuring asymmetric oxygen content and a highly elastic silicone rubber-polymer substrate with suction-cup patterns (SP). The developed MEH patch (2 cm × 4 cm) achieves an open-circuit voltage of ∼102 mV and a short-circuit current of ∼1.75 mA/m2 under ambient humidity variations. Notably, it maintains stable electrical output even when stretched up to 300% strain. The SP architecture introduced in the patch ensures robust adhesion to both dry and wet skin surfaces with the application of preload. Consequently, the stretchable and adhesive MEH patch can effectively convert breath-induced moisture energy into electric output on the philtrum, enabling self-powered monitoring of various respiratory patterns.