Coral-Inspired Superhydrophobic Triboelectric Nanogenerators with Unprecedented Wear Resistance and Sub-Zero Temperature Self-Healing Capability

Abstract

The application of self-healing superhydrophobic triboelectric nanogenerators (TENGs) is currently limited by their poor wear resistance, which stems from their reliance on nano/microscale hierarchical structures. Drawing inspiration from corals, this study presents the development of ultra-wear-resistant superhydrophobic TENGs with sub-zero temperature self-healing capability (USSS-TENGs) by incorporating rationally designed hydrophobic self-healing polyurethane (SFPU) and poly(vinylidene fluoride) nanoparticles (PVDF NPs) into iron foams. The rigid protruding structures of the iron foams protect the incorporated superhydrophobic SFPU–PVDF NPs composites by preferentially making contact with and bearing stress from foreign objects. This innovative design enables the USSS-TENGs to maintain their superhydrophobicity after repeated sandpaper abrasion, knife scratching, and even car transit, demonstrating a superior wear resistance compared to other superhydrophobic materials. Furthermore, driven by free energy minimization, the migration of SFPU to damaged areas enables the USSS-TENGs to self-heal their superhydrophobicity at −30 °C, underwater, and in vacuum. Owing to their outstanding wear resistance and self-healing superhydrophobicity, the USSS-TENGs show great application potential as smart roofs and floor tiles, capable of providing stable and durable electricity generation from processes such as precipitation, human walking/jumping, and vehicle movement. This capability has not been previously reported for superhydrophobic TENGs, irrespective of their self-healing properties.