Spatially regulated water-heat transport by fluidic diode membrane for efficient solar-powered desalination and electricity generation.

Interfacial solar-driven evaporation has attracted great research interests, given its high conversion efficiency of solar energy and transformative industrial potential for desalination. However, current evaporators with porous volume remain critical challenges by inherently balancing efficient fluid transport and effective heat localization. Herein, we propose the strategy and design of lightweight, flexible and monolayered fluidic diode membrane-based evaporators, featuring regularly arrayed macropores and dense nanopores on each side. Such a delicate microstructure offers universality in establishing asymmetric channels along macroporous-to-nanoporous to enable the diode-like directional water transport as well as facilitate the heat localization on the nanopores side. Consequently, a high evaporation rate of a maximum 3.82 kg m h can be achieved under 1 sun illumination, exceeding most 2D and 3D evaporators. Besides, the durability and practicability of our evaporators are validated through salt resistance tests, purification experiments among various contaminants, and outdoor evaluations. Moreover, the structure engineering and water-transport optimization of fluidic diode membranes also offer potentials for hydrovoltaic applications, with over 1.6 V generated by tandem devices at the ambient environment. This work provides a concept for designing high-performance monolayered membranes applicable in environmental and energy-related realms.