Tailoring Sulfonated Poly(phenyl-alkane)s of Intrinsic Microporosity Membrane for Advanced Osmotic Energy Conversion

The capture of sustainable osmotic energy from salinity gradients has huge potential to solve the global issues of energy shortage and environmental pollution. However, developing membranes with high-performance ion transport and ion selectivity to achieve a high energy conversion efficiency is challenging. Herein, based on novel sulfonated microporous polymers (SPIMs), we report a series of membranes with densely distributed and subnanometer charged nanochannels. The inefficient packing of SPIM chains not only provide an interconnected microporous structure as three-dimensional nanofluidic channels to facilitate a fast ion transport but also ensure high cation permselectivity via the negatively charged sulfonated groups. The maximum power density of SPIM membrane reaches up to 9.58 W m–2 under a 50-fold salinity gradient, which is superior to that of Nafion 117. This work can inspire the design of membrane materials for advanced osmotic energy conversion systems.