Dynamics for droplet-based electricity generators

TL;DR

This paper develops a dynamic model explaining how droplet movement influences charge transfer in droplet-based electricity generators, aiding their optimization for practical energy harvesting applications.

Contribution

It introduces a comprehensive dynamic model of surface charge density that elucidates the underlying mechanism of droplet-based electricity generators.

Findings

The droplet acts as an extension of the capacitor plate.

Changes in droplet area alter surface charge density.

The model explains power density improvements.

Abstract

The finding of droplet-based electricity generator (DEG), based on the moving boundary of electrical double layer, has triggered great research enthusiasm, and a breakthrough in instantaneous electric power density was achieved recently. However, the dynamic mechanism for such droplet-based electricity generators remains elusive, impeding optimization of the DEG for practical applications. Through comprehensive experiments, we developed a dynamic model of surface charge density that can explain the underlying mechanism for the DEGs. The spreading droplet in touch with the top electrode can be equivalently regarded as an additional part of the top plate of the DEG capacitor, and the change of droplet area causes the change of surface charge density of the plates, driving electrons to migrate between the two plates. The insight of the dynamic mechanism paves a way for optimal design and practical applications of DEGs