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Salinity gradient cells are widely used in power generation from gradient concentration solutions of one electrolyte. High ionic flux sub‐micro channels membrane can offer a high current density for salinity gradient power generation with a significant power output. Herein, based on numerical simulation model with Poisson‐Nernst‐Planck‐Navier‐Stokes (PNP‐NS) equations, a high ionic flux sub‐micro channel model with assumption is introduced that measured current is contributed by Cl− ionic flux across the membrane. An ion channel system is built for experiment, in which a glass membrane with regular symmetric sub‐micro cylindrical channels and high effective channel area is applied, ion conductance and salinity gradient energy conversion property are tested. This PNP‐NS equations model simulation fits experiment well, its mechanism is also studied by the model. In addition, by mixing artificial sea water (0.5 m NaCl) and river water (0.01 mm NaCl), the output power density of this 50‐fold salinity gradient system can achieve 4.16 W m−2, and the highest output power density will be up to 7.91 W m−2 under a 0.5 m/0.001 m 500‐fold salinity gradient. This high ionic flux membrane shows a good performance for practical application in salinity gradient power generation. [ABSTRACT FROM AUTHOR]

Although biomimetic smart gating nanochannels have been explored extensively, research on practical applications of these systems is scarce. Here, we demonstrated an engineered track‐etched asymmetric porous polyethylene terephthalate (PET) membrane modified with redox‐active Cytochrome C (Cyt C), which served as a gatekeeper due to its redox‐responsive character and excellent anion selectivity. Due to the anion‐selectivity of the membrane, we further applied it in an energy conversion device to capture the electric power from a salinity gradient. In addition, its redox‐responsive property was utilized to realize the function of power switch in concentration cell, which is capable of out‐power density conversion from 0.24 W/m2 to 0.86 W/m2 reversibly. In addition, a theoretical model based on the Poisson and Nernst‐Planck equations has been employed to simulate and explain the experimental data and illustrate the mechanism of the ionic transport process. This work presents an important paradigm for the application of stimuli‐responsive nanochannels in salinity gradient energy conversion areas and opens new and promising routes in the fields of drug delivery and bioscience. [ABSTRACT FROM AUTHOR]