Superhydrophobic Piezoelectric Device for Efficient Raindrop Energy Harvesting

Efficiently harvesting the inherent kinetic energy carried by raindrops upon impact offers considerable potential for powering microdevices. However, the conversion efficiency of the raindrop energy is low. In this paper, we present a piezoelectric energy harvesting device with a superhydrophobic and low adhesive surface for significantly improving the raindrop energy conversion efficiency. The piezoelectric energy harvesting device was prepared using a macro fiber composite (MFC) with low operating frequency, high sensitivity, and a large electromechanical coupling coefficient as a functional element. The superhydrophobic surface allowed raindrops to rebound. At the same time, the raindrops can leave the surface of the device quickly after the end of their action so as to reduce the loss of kinetic energy generated by the collision of raindrops with solid surfaces. Compared to the untreated hydrophilic device, the energy conversion efficiency of the superhydrophobic piezoelectric energy harvesting device increased 172%. Under different test conditions, the device achieved a maximum peak power density of 338 W/m3. This approach provides a promising solution for efficient raindrop energy harvesting.