Continuous Energy Harvesting from Ubiquitous Humidity Gradients using Liquid-Infused Nanofluidics

Humidity-based power generation that converts internal energy of water molecules into electricity is an emerging approach for harvesting clean energy from nature. Here it is proposed that intrinsic gradient within a humidity field near sweating surfaces, such as rivers, soil, or animal skin, is a promising power resource when integrated with liquid-infused nanofluidics. Specifically, capillary-stabilized ionic liquid (IL, Omim⁺Cl^-) film is exposed to the above humidity field to create a sustained transmembrane water-content difference, which enables asymmetric ion-diffusion across the nanoconfined fluidics, facilitating long-term electricity generation with the power density of ≈12.11 µW cm^-2. This high record is attributed to the nanoconfined IL that integrates van der Waals and electrostatic interactions to block movement of Omim⁺ clusters while allowing for directional diffusion of moisture-liberated Cl⁺. This humidity gradient triggers large ion-diffusion flux for power generation indicates great potential of sweating surfaces considering that most of the earth is covered by water or soil.