Long Life and Salt Repellent Evaporator for Efficient Continuous Solar Desalination

Interfacial solar desalination is widely regarded as a very promising strategy to alleviate global water shortages. In practical application, salting out, poor stability, short service life, complex structure preparation technology, and high cost are always the problems that people intend to solve. Here, a photothermal conversion film with hydrophilic and hydrophobic double‐layer structure is prepared by a simple brush coating process. Among them, the top is used with hydrophobic acetylene black as a photothermal material, and the bottom is used with hydrophilic melamine foam as a carrier. The evaporation rate of the photothermal conversion film can reach 1.6 kg m −2 h −1 during continuous testing at a solar coefficient. At the same time, the photothermal conversion film has a very long service life and can still work after 24 days of continuous testing. A portable desalination device with the photothermal conversion film is designed and the average evaporation rate of water can reach 1.28 kg m −2 h −1 under an average solar illumination of 0.51 kw m −2 in outdoor environments.