Defect‐Tolerant and Scalable Diffusio–Osmotic Power Generation with Sulfonated Covalent Organic Framework Membrane

Salinity gradient energy extracted with the reverse electrodialysis technique is attracting great interest and has been suggested as a promising renewable and stable energy source. However, the reverse electrodialysis relies on highly charge‐selective membranes, causing a range of problems including the selectivity–permeability trade‐off, strong concentration polarization, and strict requirement on the material structure, severely limiting its viability for large scale applications. We demonstrate these problems may be addressed by adopting the diffusio–osmosis process to generate power using sulfonated covalent framework membranes (COF), which does not require any charge selectivity. As a result, the membrane shows much higher power density compared to similar‐sized membranes and enables much higher scalability. Remarkably, the generator has loose requirement on material structure and could largely maintain its power generation performance even when a substantial number of pinholes are present. This could make the material fabrication significantly easier than before. We expect our work to advance the practical application of salinity gradient energy extraction.