Resonance-enhanced hybrid-principle droplet electricity generator based on femtosecond laser-ablated superhydrophobic surface

Abstract

Maximizing the energy harvested from falling droplets through the development of hybrid droplet electricity generators holds significant promise for solving distributed power supply issues and mitigating the energy crisis. However, current multi-principle droplet generators still face challenges such as high energy dissipation, instability, and dependence on rainy weather. In this study, we developed a droplet-based resonance-enhanced hybrid generator (RHG) that augments the energy conversion efficiency through the synergistic application of electromagnetic induction and the triboelectric effect. By employing femtosecond laser ablation to create micro-nano structures on the triboelectric materials, a three-fold enhancement in peak output voltage was achieved compared to smooth surface. Moreover, micro-nano structures facilitate superhydrophobic, preventing residual liquid droplets and contaminating particles from remaining on the surface. In the resonant state (f≈4.3 Hz), a single droplet can generate up to 54.8 μC of transferred charge and 306 V of output voltage, increasing energy conversion efficiency to 12.6%. It is also demonstrated that this device can charge a 10 mF capacitor to 1.8 V within 400 s and power a wireless temperature and humidity sensor through a capacitor circuit. This lays the foundation for the efficient collection of green energy and the future of self-powered sensors.