Microfluidic-Mediated Orientation Nanoengineering for Enhanced Osmotic Energy Harvesting.

Charged two-dimensional nanosheet-assembled membranes exhibit considerable promise for sustainable osmotic energy harvesting. However, conventional techniques such as filtration often lead to uncontrollable nanostructure geometries, which can substantially diminish the ion regulation efficiency of the membranes. In this work, we developed a novel microfluidic-mediated oriented nanoengineering approach for the continuous construction of highly oriented bacterial cellulose nanofiber (BCNF)/MXene composite membranes. Compared to traditional filtration membranes, the orientation angle distribution narrows from 0-80° to 0-20°. Moreover, these membranes achieved the maximum power density of 23.7 W/m under a 50-fold NaCl salinity gradient and 52.0 W/m under standard solar simulator conditions, significantly surpassing the performance of previously reported MXene-based filtration membranes and commercial standards. This work introduces a novel orientation nanoengineering technology through dynamic nanomaterial assembly, aimed at optimizing nanostructures, thereby significantly improving applications in structural materials, renewable energy, and specialty membranes.