A Bioinspired Asymmetric Heterostructure for Self-Sustaining Hydroelectricity Generators via Synergistic Hygroscopicity and Evaporation

Hydroelectricity generators capable of harvesting electricity directly from the chemical energy of atmospheric moisture represent a sustainable technology for self-powered sensing and wearable electronics. However, existing designs suffer from output decay after water saturation and unstable performance under environmental fluctuations, hindering their applications in dynamic and variable wearable conditions. Inspired by the water-transport function of plant stems and leaves, we developed a fabric-based self-sustaining hydroelectric generator (SHEG) that integrates moisture adsorption and water evaporation into a continuous energy-harvesting cycle. The SHEG features an asymmetric heterostructure comprising a hygroscopic ionic-gel layer for rapid moisture capture and proton release, and an evaporative layer based on MoS2/MXene van der Waals heterojunctions that provide confined nanochannels for selective ion transport and directional evaporation. This hierarchical design maintains a stable water gradient, delivering a sustained electrical output for over 120 h and a maximum power density of 377 nW m–2 at 60% RH. The SHEG also responds to wind, heat, and sunlight, which is demonstrated in wearable real-time sensors for respiration and motion monitoring, showcasing its promise as a self-powered platform for next-generation electronics.