Large‐Area Covalent Organic Polymers Membrane via Sol–Gel Approach for Harvesting the Salinity Gradient Energy

Abstract Many materials with nanofluidic channels are exploited to achieve salinity gradient energy conversion. However, most materials are fragile, difficult to process, or only prepared into a limited size, which greatly restricts their practical application in the future. Herein, a covalent organic polymers membrane with high mechanical property and stability is fabricated, which can keep integrity in harsh conditions for up to 1 month. In addition, by using the sol–gel approach, a large‐area membrane with an area of 26 × 26 cm is expediently fabricated in lab conditions. When the membrane is applied to salinity gradient energy conversion, the maximum output power density is up to 6.21 W m⁻². This work provides a simple method for the fabrication of large‐area membrane for salinity gradient energy conversion in future real‐world applications.