Using Smart Nanochannels as a Power Switch in Salinity Gradient Batteries

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. On track: A track‐etched asymmetric porous polyethylene terephthalate (PET) membrane modified with redox‐active Cytochrome C (Cyt C) has been engineered to serve as a gatekeeper due to its redox‐responsive nature and anion selectivity. Its redox‐responsive properties were used to realize control over power output in concentration cell, which was capable of reversible out‐power density conversion from 0.24 W/m2 to 0.86 W/m2.