Droplet-Enabled Controllable Manipulation of Tribo-Charges from Liquid–Solid Interface

Abstract

Efficient utilization of electrostatic charges is paramount for numerous applications, from printing to kinetic energy harvesting. However, existing technologies predominantly focus on the static qualities of these charges, neglecting their dynamic capabilities as carriers for energy conversion. Herein, we report a paradigm-shifting strategy that orchestrates the swift transit of surface charges, generated through contact electrification, via a freely moving droplet. This technique ingeniously creates a bespoke charged surface which, in tandem with a droplet acting as a transfer medium to the ground, facilitates targeted charge displacement and amplifies electrical energy collection. The spontaneously generated electric field between the charged surface and needle tip, along with the enhanced water ionization under the electric field, proves pivotal in facilitating controlled charge transfer. By coupling the effects of charge self-transfer, contact electrification, and electrostatic induction, a dual-electrode droplet-driven (DD) triboelectric nanogenerator (TENG) is designed to harvest the water-related energy, exhibiting a two-order-of-magnitude improvement in electrical output compared to traditional single-electrode systems. Our strategy establishes a fundamental groundwork for efficient water drop energy acquisition, offering deep insights and substantial utility for future interdisciplinary research and applications in energy science.