High-Performance and Scalable Hydrovoltaic Power Generation via Seawater-Driven Ion Transport in 3D Porous Non-Woven Fabrics

This study reports a simple, high-performance, and cost-effective hydrovoltaic power generator driven by natural seawater. The device combines 3D porous non-woven fabrics with asymmetric copper–aluminum electrodes, offering flexible design and excellent environmental adaptability. The stochastic network of the non-woven fabric acts as an efficient ion-transport highway, accelerating electrolyte infiltration via its large surface area and strong capillary wicking. Leveraging the high ionic strength of seawater compresses the electrical double layers and minimizes internal resistance, boosting the short-circuit current by 25 times compared with deionized water. Short-circuit currents of ~60 μA and open-circuit voltages of ~650 mV were each maintained for over 1200 s. Systematic optimization shows that a 1 mm electrode spacing balances ionic transport and parasitic losses, delivering a peak power of 12.5 μW. Scalability is demonstrated by integrating multiple units: three parallel units scale the current to 173 μA, while three series units increase the voltage to 1500 mV, providing a practical strategy for sustaining low-power electronics. This work establishes non-woven fabric-based generators as a robust platform for harvesting energy from naturally abundant seawater, offering a practical and scalable design for next-generation self-powered small-scale devices.