Fig. 6: Effect of COF-TpPa/PAN permselectivity under various ionic conditions.

a Graph depicting the mobility ratio of cations and anions through the COF-TpPa/PAN membrane, as calculated by the GHK equation. b I − V characteristics observed under a KCl concentration gradient (3 M | | 0.3 M). c Schematic representation illustrating the regulation of the membrane’s surface charge by selective ion adsorption, including polarity and intensity. d Plots showing the electricity delivered to an external circuit with a load resistance under a KCl concentration of 3 M.