Water-solid triboelectrification with self-repairable surfaces for water-flow energy harvesting

Highlights: • A self-repairable water-TENG based on superhydrophobic surface is fabricated. • The superhydrophobic triboelectrode can be prepared in a large area by a simple bonding method. • A self-repairable W-TENG is achieved by restorable superhydrophobicity. • A current output of 30 μA can be obtained with the water flow rate of 0.6 m/s. -- Abstract: A new repairable water-solid triboelectric nanogenerator (W-TENG) based on superhydrophobic surface is fabricated to harvest water-flow energy. The superhydrophobic triboelectrode with micro- and nanostructures is prepared by adhering polyvinylidene fluorid (PVDF) nanospheres to a polyimide (PI) film through a double-sided adhesive tape followed with a fluorination process. When water flows through the superhydrophobic surfaces with a flow rate of 0.3 m/s, the W-TENGs array could easily harvest water-flow energy to obtain a current output of 20 μA which can light more than 30 commercial LEDs or be used for self-powered sensors to detect concentration change of chemicals pollutants in water. More importantly, when the superhydrophobic surface is damaged during long-term working, it could be self-repaired by releasing the fluorinated alkyl silane packed in pores of adhesive tape surface, and a self-repairable W-TENG is achieved. Given its easy fabrication and self-healing properties, the W-TENG and W-TENGs array have promising practical use in oceans and rivers energies harvesting, especially in some remote areas, for early warning, indicator light and self-powered detection sensors.