A Bioinspired Nanocomposite Solar Evaporator With Interfacial Ion Triggered Hydration Chemistry for Sustainable Desalination

Interfacial solar desalination presents a green solution to the global freshwater crisis, yet its efficiency in hypersaline brines is often limited by trade-off between evaporation rate and salt resistance. Inspired by Salicornia europaea , we develop an aerogel-hydrogel nanocomposite evaporator (ZHGA) that combines structural and molecular synergies. The ZHGA utilizes a longitudinally aligned graphene aerogel framework, which ensures efficient photothermal conversion, rapid water transport and self-floating capability. On its surface, a specially designed zwitterionic hydrogel skin is grown, which exhibits a pronounced anti-polyelectrolyte effect. This character allows the hydrogel skin to absorb substantial amounts of water from brine, thereby diluting the salt concentration and suppressing salt precipitation; the hydrogel also reduces evaporation enthalpy through mediating the binding network of water. The obtained ZHGA evaporator achieved an evaporation rate of 5.03 kg m − 2 h − 1 in 3.5 wt.% brine, maintained 98.5% efficiency over five eight-hour cycles in 15 wt.% brine, and prevented salt crystallization during continuous evaporation, ensuring sustainable and durable use. The produced fresh water not only meets the WHO drinking water standard but also supports plant growth, making it suitable for agricultural applications. This design realizes rapid water supply and salt rejection, paving the way for next-generation solar desalination systems.