Fast Charging and High Power Ionogel‐Based Rain Energy Harvester

Abstract The growing demand for sustainable energy has triggered the exploration of innovative solutions to harness clean and renewable sources. In this pursuit, harvesting rain energy has emerged as a promising approach due to its unlimited availability. However, traditional droplet‐based harvesters face several challenges, including a long charging period, low electrical power output, and fast charge dissipation. This study presents an innovative ionogel‐based rain energy harvester that overcomes these limitations. The key advancement lies in the stable polarized interface created by the ionogel, which enables rapid charging and high charge retention, leading to a significant instantaneous power within the first few raindrops and achieving an 8‐fold increase in saturation performance over conventional design. The harvester only requires 25 droplets to reach saturation and maximum electrical output, achieving an impressive power density of 235.11 W m⁻² and a conversion efficiency of 6.77%, being the highest recorded for ionogel and hydrogel‐based droplet energy harvesters. Additionally, the adhesive nature of the ionogel enhances the device's stability and versatility in varying energy generation and steam leakage applications. This work advances the pursuit of sustainable energy harvesting by bridging materials science with practical application.