Self-Healing and Recyclable Tribolayer Constructed Cotton-Fabric-Based Direct-Current Tribovoltaic Nanogenerator toward Durable and Sustainable Mechanical Energy Harvesting

The combination of renewable cotton and recyclable tribolayer to construct durable direct-current tribovoltaic nanogenerators (TVNGs) demonstrates significant potential for addressing the issue of electronic waste. However, developing sustainable tribolayers for TVNGs that simultaneously possess long-term durability and recyclable functionality to extend service life remains a major challenge. Herein, we demonstrate a facile method to fabricate sustainable cotton-fabric-based TVNGs with a self-healing and recyclable tribolayer made of a biocompatible polyvinyl alcohol skeleton combined with semiconductor fillers and an aluminum sliding layer. The resultant TVNG exhibits a maximum open-circuit voltage of 1.08 V and a peak current of 0.72 mA. Based on reversible dynamic hydrogen-bond interactions, the fractured tribolayer can autonomously repair and further improve its triboelectric behavior, achieving up to 90% of the original values. Furthermore, the discarded tribolayer in TVNGs can be removed through hot water dissolution and recoating on cotton fabric to construct reused TVNGs, which can retain over 80% of the original value. We have also conducted stability tests and tensile mechanical and load resistance analysis for the TVNG. This work proposes a sustainable TVNG based on the coating of a self-healing tribolayer on natural cotton fabric, which provides a sustainable approach toward the application of renewable materials in the nanogenerator field.