Ternary Molecular Co-Assembling Heterogeneous Membranes for High-Efficiency and Anti-Biofouling Osmotic Energy Conversion.

Low-cost access to abundant, green osmotic energy through nanofluidic membranes holds promise to solve the economic, energy, and environmental trilemma. Despite considerable promising explorations, developing a nanofluidic membrane with ease of fabrication, high performance, and superior biofouling resistance remains a challenge. Here, a unique ternary molecular co-assembly strategy is presented to provide a solution. L-glutathione, Ag ions, and histamine can co-assemble into twisted nanofibers through coordination and cross-linking. The co-assembly within anodic aluminum oxide (AAO) nanochannels, reinforced by polyvinyl alcohol (PVA), creates a heterogeneous membrane (AAO@GHAg/PVA) characterized by enhanced stability and mechanical strength. The AAO@GHAg/PVA membrane features asymmetric nanochannels that facilitate anion-selective unidirectional transport, achieving a peak output power density of 17.5 W·m under a 50-fold salinity gradient. The inclusion of Ag endows AAO@GHAg/PVA with superior biofouling resistance, allowing it to maintain a maximum power density of 16.6 W·m in a real seawater/river water environment. Interestingly, replacing histamine with spermine further boosts performance to 21.4 W·m, demonstrating the extensibility of the molecular precursors. This work opens up a new avenue for the facile construction of high-efficiency nanofluidic membranes for osmotic energy harvesting.