Nanoarchitected Hydrogel Membranes With Tri‐Continuous Ion Pathways for Antibiofouling Salinity‐Gradient Energy Harvesting

ABSTRACT Asymmetric nanoporous membranes hold great promise for salinity‐gradient energy (SGE) harvesting, yet their practical application is hindered by biofouling‐induced degradation in ion selectivity and transport efficiency. Here, we present a nanoarchitected heterogeneous ionic diode membrane (PATM/PG‐AAO) that integrates a phytic acid (PA)‐regulated polyelectrolyte hydrogel with a pore‐gradient alumina nanochannel substrate. This design establishes a tri‐continuous ion transport framework that synergistically couples space‐charge‐governed ion selectivity with geometry‐enhanced ionic rectification, thereby promoting efficient and regulated ion transport. Importantly, incorporation of PA not only introduces a high density of fixed charges but also reinforces the hydrogel network via multivalent interactions, leading to enhanced mechanical robustness and improved anti‐swelling capability. As a result, the membrane achieves a high power density of 52.86 W m −2 under a 5 M/0.01 M NaCl gradient, outperforming most reported nanofluidic systems. Meanwhile, PA endows the membrane with outstanding antibiofouling and antimicrobial properties by suppressing bacterial adhesion and enabling effective inactivation of Escherichia coli and Staphylococcus epidermidis , thereby maintaining stable energy output under bacterial exposure. This work highlights an effective strategy for integrating high‐performance ion transport with robust biofunctionality, advancing the development of practical SGE harvesting technologies.