High density ferroelectric charges enabled droplet vibration nanogenerator with extraordinary output

Abstract

Droplet vibration nanogenerator is a promising technology that can transform kinetic energy into electric energy. In this paper, a vibration droplet nanogenerator based on lead zirconate titanate (PZT) (PZT-VDNG) is proposed, which utilizes the change in double electron layer area at the droplet/PZT interface, hence an extraordinary charge variation, induced by mechanical vibrations. Our approach innovatively combines a high fixed surface charge density with ionic solutions to significantly enhance energy conversion efficiency. A theoretical model of the PZT-VDNG is established, showing excellent consistence with the experimental results. The energy conversion efficiency and its correlation with the materials involved, device structure and circuits used, are investigated in detail. Under the optimal conditions of a vibration frequency of 5 Hz, an amplitude of 2 mm, and a droplet size of 40 μL, a short-circuit current output of 31.43 μA and an open-circuit voltage of 1.5 V are obtained by a single vibration of a droplet, respectively, 111 and 37.5 times larger as compared to those from a VDNG with PTFE polymer layer. This marks a significant leap in the efficiency and potential applications of vibration nanogenerators.