Conducting Polymer Nanofluidic Membrane for Electrically Regulated Osmotic Energy Harvesting

Electric eels (Electrophorus electricus) possess intelligent electrogenic capabilities governed by action potential from the nervous system, wherein they emit low-voltage pulses for electrolocation of prey, while discharging high-voltage electricity for predation or defense. Inspired by the intelligent biological electricity regulation mechanism of eels, herein, an electrically regulated osmotic energy conversion system is reported, composed of polystyrene sulfonate anion (PSS) doped polyaniline (PANI) conducting polymer membrane (PSS-PANI). This PSS-PANI nanofluidic membrane demonstrates a redox-potential-responsive surface-charge polarity due to the doping/dedoping of PSS. An oxidation potential applied to the PSS-PANI membrane enhances the cation selectivity due to the high doping degree of PSS polyanions in the PSS-PANI membrane, which leads to an osmotic energy conversion with a high output power density. While the PSS-PANI membrane is in an electrochemically reduced state, the doping degree of PSS polyanions decreases, leading to a low output power density. The osmotic energy conversion ability can be reversibly regulated through the electrochemical redox reaction, which exhibits potential applications in on-demand osmotic energy conversion.