Electric Eel‐Inspired Janus Nanofiber Membrane With Structure‐Charge Dual Asymmetry for Efficient Moisture‐to‐Electric Conversion and Self‐Powered Intelligent Perception

ABSTRACT Moisture‐electric generators (MEGs) harvest the chemical potential of ambient water vapor as electricity. The central limitation is not ion generation alone, but the failure to coordinate ionic release, directional flux, and interfacial separation, allowing diffusion and back migration to dissipate the available potential. Inspired by electric eel electrocytes, we introduce a structure‐charge dual‐asymmetric (SCD) framework that integrates ion generation, migration, and rectification. A Janus nanofiber membrane comprising poly(vinyl alcohol)/phytic acid (PVA/PA) and PVA/PA‐LiCl encodes the structural asymmetry required for differential moisture uptake, ion release, and chemical potential. Charge‐asymmetric poly(diallyldimethylammonium chloride) (PDDA)/LiCl and poly(sodium 4‐styrenesulfonate) (PSSA)‐modified electrodes impose a collinear self‐driven electric field. Coupling the chemical‐potential gradient to field‐driven rectification converts stochastic diffusion into sustained directional ionic flux. At 97% relative humidity (RH), this coupled pathway delivers an open‐circuit voltage (V OC ) of 0.86 V, a short‐circuit current (I SC ) of 49.3 µA, and a maximum power density (P max ) of 7.1 µW cm −2 . Stable output is retained for 25 days under naturally fluctuating humidity. The same ionic architecture supports self‐powered noncontact sensing, intelligent recognition, and humidity regulation during fruit storage. Rather than another route to higher output, the SCD concept establishes ionic‐flux engineering as a transferable principle for moisture‐to‐electric conversion and related iontronics.