Slippery contact on organogel enabling droplet energy harvest

Liquid-solid-based triboelectric nanogenerators (LS-TENG) are new tools for collecting energy from water in nature. Recent efforts have been made on LS-TENG based on superhydrophobic surfaces with faster sliding speed of water droplets and more efficient LS separation comparing to the hydrophobic ones, resulting in higher energy output performance. However, there is a tradeoff between sliding speed and LS contact area. Solving this tradeoff will raise both the output capability and energy conversion efficiency. In this study, we demonstrate a new TENG based on liquid-organogel (LG) interface. By introducing organogel as the triboelectric layer, a new slippery contact mode is established between water droplets and organogel. In physical chemistry, the slippery contact is applauded for the high sliding speed and large contact area, which creates an opportunity for our current task. During sliding of a water droplet on LG-TENG, the electrostatic induction yielded a transferred charge of ∼12 nC per droplet, which is 3 times greater than that from control experiment based on LS-TENG. In despite of the high output performance, the LG-TENG is of low-cost and up-scalability, which make it a ready candidate for harvesting distributed energy from natural resources on the vast outdoor facilities.