Stabilizing the Energy Harvesting of PVDF-Fabric-Based TENGs Exposed to Moisture and Dust Particles by O-2 and CF4 Plasma Treatments

Superhydrophobic polyvinylidene fluoride (PVDF) fabrics comprising electrospun PVDF yarns are developed via O-2 and CF4 plasma treatments to achieve stable triboelectric energy harvesting performance. The dynamic water droplet behavior, self-cleaning ability, and electrical output performance of the fabrics before and after sequential treatments with O-2 plasma for 12 min and CF4 plasma for 4 min are measured. The electrical output performance for all fabric-based piezoelectric nanogenerators (PENGs) is higher than that for PVDF film-based PENGs. Furthermore, plasma treatment enhances the electrical output performance of all triboelectric nanogenerators (TENGs), particularly the fabric-based TENGs. Due to the increased water repellency and self-cleaning ability conferred by the plasma treatment, all superhydrophobic fabric-based TENGs exhibit improved stability in electrical output performance when exposed to water or dust particles. In contrast, plasma treatment has little or no effect on the stability of the output performance of the PVDF-film-based TENGs. The superhydrophobic PVDF fabric with the highest water repellency and self-cleaning efficiency exhibits the most stable triboelectric energy-harvesting performance when exposed to water and dust particles. Because of its micro/nanoscale hierarchical roughness and open-pore structure, the optimal plasma-treated PVDF fabric has a reduced contact area with water droplets, rendering this fabric favorable for repelling water droplets and removing particles.