Ultra-stretchable triboelectric nanogenerator as high-sensitive and self-powered electronic skins for energy harvesting and tactile sensing

Rapid development of wearable electronic devices stimulates various requirements for power supply devices, such as sustainability, maintenance-free and stretchability. Herein, we fabricate a flexible and self-powered electronic skin (e-skin) based on an ultra-stretchable triboelectric nanogenerator (STENG) by multilayered thermoplastic polyurethane (TPU)/silver nanowires (AgNWs)/reduced graphene oxide (rGO). Due to the ultra-stretchable property of the TPU fibrous mats and the synergistic effect of the multilayered AgNWs/rGO microstructure, our e-skin demonstrates excellent stability and high stretchability (200% strain). The e-skin (2 × 2 cm²) delivers a high open-circuit voltage (202.4 V) and a large instantaneous power density (6 mW/m²), which can be used as an efficient energy supply device. Whereas, our e-skin possesses a high sensitivity (78.4 kPa⁻¹) and a fast response time (1.4 ms) towards pressure, demonstrating its excellent tactile sensing capability. On the basis of the excellent performances, the e-skin can sense strength and trajectory of motion of the mechanical stimulus, clear and accurate results have been obtained. The results provide a new and practical strategy for fabricating STENG based high performance and self-powered e-skin for soft robots, human-machine interaction and internet of things.