Ru Song, Yanlong Shi, Ningshuang Zhang, Peng Wang, Shiyou Li
Freshwater scarcity has become one of the primary challenges hindering sustainable economic and social development. Solar water evaporation, which harnesses "free energy" from sunlight, is regarded as an eco-friendly technology for freshwater production. Conventional volumetric evaporation systems experience substantial heat loss due to bulk water heating, limiting the photothermal conversion efficiency to only 30%–45%. The interfacial solar evaporation technology that has emerged in recent years has dramatically improved photothermal efficiency by localizing solar heat at the air-liquid interface. Firstly, for an in-depth understanding of the development and application of the new technology, this review presents a comprehensive examination of various evaporator designs and their own characteristics. Secondly, given the significant potential demonstrated by 3D evaporators, we discuss the recent advances in 3D evaporators, focusing on four key aspects: enhance light absorption, innovative 3D structures, optimize water transport channels, and salt resistance. Finally, we discuss the current issues and challenges facing the practical application of solar evaporation technology in freshwater production.