A Novel Aerogel-Based Solar Evaporator with Triple-Layered Low-Tortuosity Pore Structures for Ultra-High Salt Resistance

Abstract

Solar-driven interfacial evaporation is a potential strategy to address freshwater scarcity. However, simultaneously achieving high evaporation performance and effective salt resistance remains a significant challenge. Herein, a triple-layered aerogel-based solar evaporator with low-tortuosity pore structures (Tri-ASEL) is constructed. Benefiting from the unique pore structures of Tri-ASEL, it not only exhibits excellent water transport capacity, which is significantly increased by 237.5% compared to that of the aerogel-based solar evaporator with uniform pore structures, but also effectively reduces the downward heat transfer owing to the low thermal conductivity of the top layer. Meanwhile, compared with the aerogel-based solar evaporator with triple-layered pore structures (Tri-ASE), Tri-ASEL can reduce the resistance of ion diffusion and shorten the diffusion pathways through the low-tortuosity pore structures. Because of the effective coordination of the contradiction among the water transport, ion diffusion, and thermal insulation, Tri-ASEL achieves a high evaporation rate of 2.803 kg m⁻² h⁻¹ and exhibits a remarkable evaporation efficiency of 97.95% under 1 sun. More importantly, it demonstrates excellent salt resistance and can operate stably in ultra-high salinity brine (25 wt%) for more than 8 h without salt crystallization. This study provides a new approach for optimizing the structure design of evaporators.