Thermal-localized and salt-resistant polyacrylonitrile/polyvinylidene fluoride aerogel for efficient solar desalination

Solar desalination is considered as an effective and environmental-friendly pathway against global water scarcity but still suffers from unnecessary heat loss, inadequate water supply, and salt deposition. To address these issues, this work proposes that a PAN/PVDF@ nano carbon black composite aerogel (PPCA) fabricated by a new "multiangle splicing freezing" method in dimethyl sulfoxide solvent can realize stable and efficient evaporation on the water surface. PPCA with inclined channels ensures higher pressure and faster flow rate, meanwhile the hydrophilic/hydrophobic interface can prevent water transmission and localize heat. Benefitted from this structure, PPCA delivers highly efficient energy (93.2%) under 1.0 sun, stable water output (~1.46 kg m-2 h-1), and exhibits a superior salt-resistant property without salt deposition on the evaporation surface even in the simulated Dead Sea for continuous 24 h illumination. With the stable evaporation performance of high-salinity brine, this design has great potential for sustainable solar desalination.