Enhancing Sustainable Energy Conversion Efficiency by Incorporating Photoelectric Responsiveness into Multiporous Ionic Membrane

The evolution of porous membranes has revitalized their potential application in sustainable osmotic-energy conversion. However, the performance of multiporous membranes deviates significantly from the linear extrapolation of single-pore membranes, primarily due to the occurrence of ion-concentration polarization (ICP). This study proposes a robust strategy to overcome this challenge by incorporating photoelectric responsiveness into permselective membranes. By introducing light-induced electric fields within the membrane, the transport of ions is accelerated, leading to a reduction in the diffusion boundary layer and effectively mitigating the detrimental effects of ICP. The developed photoelectric-responsive covalent-organic-framework membranes exhibit an impressive output power density of 69.6 W m-2 under illumination, surpassing the commercial viability threshold by approximate to 14-fold. This research uncovers a previously unexplored benefit of integrating optical electric conversion with reverse electrodialysis, thereby enhancing energy conversion efficiency. Concentration polarization (CP) poses a substantial constraint on the maximum attainable power density in the context of salinity gradient energy extraction through reverse electrodialysis. This issue can be effectively alleviated by incorporating photoelectric responsiveness into a multiporous ionic membrane, resulting in an impressive output power density of 69.6 W m-2 when exposed to light.image