Three-Dimensional Piezoelectric-Triboelectric Hybrid Nanogenerators for Mechanical Energy Harvesting

This study presents experimental results on the production,characterization,and applications of three-dimensionally designed piezoelectric-triboelectrichybrid nanogenerators. The hybrid nanofiber mats were manufacturedusing poly(vinylidene fluoride) and thermoplastic polyurethane asthe piezoelectric and triboelectric counter materials, respectively,by the simultaneous electrospinning process. Surface-engineering agentssuch as poly(vinylpyrrolidone), reduced graphene oxide nanoplates(rGO NPs), and zinc oxide nanowires (ZnO NWs) were utilized in three-dimensionaldecoration stages. The nanofiber surfaces were roughened using thesacrifice method, followed by the application of electrospraying andhydrothermal growth techniques to decorate the nanofibers with rGONPs and ZnO NWs, thereby enhancing the device. The resulting hybridnanogenerators were subjected to periodic compression via an appliedforce, resulting in a 75.0% increase in voltage density and a 169.23%increase in current density compared to the neat hybrid nanogenerator,thanks to the surface roughening treatment. Furthermore, the decorationsof rGO NPs and ZnO NWs on the nanofibers contributed to a 271.80%increase in voltage density and a 230.77% increase in current density,reaching values of 2.35 kV/m(2) and 3.40 mA/m(2), respectively. The nanogenerators were also tested in various applications,including energy storage, device powering, and textile sensors, todemonstrate their practicality.