Solar-driven interfacial evaporation for sustainable desalination: Evaluation of current salt-resistant strategies

In recent years, solar-driven interfacial desalination (SDID) has emerged as an effective, environmentally friendly and promising strategy to address the shortage of freshwater resources. However, during the evaporation process, salt crystals will precipitate at the photothermal interface, which will hinder the water transfer and light absorption problems of the evaporator and seriously affect the long-term stability and large-scale practical application of SDID system. To solve the salt accumulation problem and improve the evaporation performance, various advanced photothermal materials and novel structural designs have been reported for the preparation of high-performance solar evaporators. This review begins with a brief introduction to salt accumulation, which is currently the main challenge hindering the stable operation of solar evaporators. The second part focuses on five current state-of-the-art salt resistance strategies: diffusion and convection, Marangoni effect, Janus structure, salt ion repulsion effect and localized salt crystallization. For each strategy its application and mechanism in the evaporation process is described in detail, and the advantages and limitations are compared. We conclude by aiming to provide a clear and comprehensive overview of the challenges and opportunities facing SDID technology, thus stimulating new ideas for future evaporator design and providing guidance for future research.