Solar desalination: current technological status and future directions

Abstract Freshwater scarcity is a pressing global challenge that demands sustainable and energy-efficient solutions. Solar desalination offers a promising pathway by leveraging the abundant, renewable energy of the sun to produce potable water while reducing dependence on fossil fuels. This review critically examines the current technological status and future directions of solar desalination, with emphasis on solar thermal desalination (STD) and solar electrochemical desalination (SED). STD replicates the natural evaporation–condensation cycle, and recent advances in photothermal materials, such as carbonaceous nanostructures and plasmonic nanoparticles, have significantly enhanced solar absorptivity and thermal efficiency. However, high energy consumption and cost remain barriers to large-scale deployment. SED introduces an emerging paradigm by coupling solar energy with ion transport and redox chemistry, enabling simultaneous desalination and value-added co-production of hydrogen, formate, and reactive chlorine species (RCS). Despite its potential for high efficiency and multifunctionality, SED faces challenges related to ion selectivity, stability, and scalability. Hybrid systems that integrate thermal, photovoltaic, and electrochemical approaches show promise for improved performance and reduced costs. Techno-economic analyses underscore the need for cost-effective materials, optimized system architectures, and supportive policies to accelerate commercialization. Overall, solar desalination is positioned as a transformative technology to address water scarcity while advancing sustainable energy integration and environmental stewardship.