Breathable, self-healable, washable and durable all-fibrous triboelectric nanogenerator for wearable electronics

Abstract

Triboelectric nanogenerators (TENGs) have become a significant player in the expanding wearable electronics arena due to their high output voltage, diverse material compatibility, and straightforward design. For optimal performance in wearables, TENGs need specific characteristics like air permeability, durability, washability, and self-healing capability. In a novel approach, we utilized polybutadiene-based urethane (PBU), equipped with Diels-Alder networks, as a triboelectric material. This choice lends our design washability, self-healing capabilities, and considerable mechanical strength. PBU's abundant amine groups are key to enhancing its triboelectric properties, facilitating electron transfer between materials and contributing to high charge density. We also used polyvinylidene fluoride (PVDF) electrospun fibers as the negative layer, chosen for their electron-attracting ability and flexibility. These components were electrospun onto a conductive fabric coated with copper-nickel to optimize the contact area and increase wearability. Our device, measuring 2500 mm2, generated approximately 113 V and a rectified current of around 8 μA at 0.98 kPa external pressure and a 5 Hz frequency. Impressively, it maintained performance despite thousands of wash cycles and various deformities, demonstrating unique self-healing abilities following severe surface damage. The TENG has demonstrated its real-world potential by powering up to 150 LEDs, efficiently operating calculators, thermometers, hygrometers, and even functioning as a warning device through normal walking motion. Moreover, its air permeability allows for electricity generation from the wearer's breath when attached to a regular mask, as evidenced by successful LED lighting by human normal breathing.