Bioinspired and Engineered Ion‐Selective Membranes Toward High‐Flux and High‐Selectivity Energy Devices

Nanofluidic membranes with precise ion selectivity and ultrahigh permeability are central to advancing electromembrane technologies for energy generation, storage, water purification, and environmental monitoring. The performance of these systems hinges on the ability of membranes to efficiently and selectively transport ions. However, synthetic ion-selective membranes (ISMs) face a fundamental trade-off: increasing ion selectivity typically reduces permeability, and vice versa. Overcoming this trade-off is essential for realizing next-generation ISMs with enhanced performance. This review summarizes recent progress in addressing the selectivity-permeability trade-off through innovative membrane architectures, advanced fabrication methods, material engineering strategies, and modeling tools that clarify structure-property-performance relationships. Biological ion channels serve as benchmarks, offering ultra-efficient ion transport via precise control of pore size, surface charge, pathway length, and rectification effects. Drawing on these natural systems, we highlight bio-inspired strategies for enhancing synthetic membrane performance. We also discuss the role of ISMs in electrochemical applications and assess remaining challenges in achieving high ion flux without compromising selectivity. Emerging solutions including hybrid membrane systems, advanced nanomaterials, and AI-assisted design present promising pathways forward. The review concludes by outlining future directions that integrate computational modeling with experimental validation to develop efficient, scalable, and sustainable membrane technologies.