Porous Graphene/Polyimide Membrane with a Three-Dimensional Architecture for Rapid and Efficient Solar Desalination via Interfacial Evaporation

The solar desalination via interfacial evaporation has shown great potential in addressing the freshwater scarcity issue. However, the evaporation rate and solar thermal conversion efficiency of the current photothermal materials (flat membranes, papers, and thin films) have almost been pushed to the upper limit. In order to further improve the energy efficiency, in this work, we developed a highly porous laser-induced graphene/polyimide (LIG/PI) photothermal membrane with a three-dimensional (3D) architecture through electrospinning and laser ablation techniques. The 3D structure of the LIG/PI membrane increases the evaporation area and reduces the energy loss caused by diffuse reflectance of light. With the assistance of a thermal insulator and water pumping channels, the LIG/PI membrane achieves a high evaporation rate of ∼1.42 kg m–2 h–1, a high solar thermal conversion efficiency of ∼92.55%, and long-term evaporation stability in a high-concentration saline solution under 1 sun illumination. Such a stable photothermal membrane may provide important insights into designing rapid and efficient interfacial evaporation systems.