Achieving Ultrahigh Voltage Over 100 V and Remarkable Freshwater Harvesting Based on Thermodiffusion Enhanced Hydrovoltaic Generator

Abstract

AbstractEvaporative hydrovoltaic generators hold significant potential for alleviating water‐energy crisis, but low output voltage configurations due to the slow phase transition rate of water molecules and the intricate nature of integration limit their applications. Herein, a lotus‐inspired interfacial evaporation‐driven hydrovoltaic generators (IEHVG) is developed for efficient generation of water vapor and electricity from seawater instead of freshwater and achieves an ultrahigh voltage output higher than 100‐volt level through forested IEHVG integration. The biomimetic hydrogel is developed with specific liquid transport channels, graphene quantum dots/MXene nanocomposites, and gradient hydrophobic interface for highly enhanced photothermal evaporation and electricity generation by mimicking the transpiration process of a “stems‐leaves of lotus”. The synergistic thermodiffusion effect leads to the output power density of IEHVG reaches up to 45.6 µW cm−2 and can power electronic devices or charge commercial supercapacitors. The freshwater‐electricity cogeneration integrated system consisting of 192 IEHVG units can harvest a record‐breaking voltage reaching 105 V and a high freshwater harvesting rate up to 2.0 L m−2 h−1 from seawater in a well‐lit outdoor area. This work demonstrates that IEHVG offers a novel concept for modular freshwater and high‐voltage power sources access on offshore work platforms.