Scalable, high-efficiency porous monolithic polymer foam for solar-driven interfacial water evaporation and lithium extraction

Freshwater scarcity remains a critical global challenge, prompting the development of sustainable solutions like solar-driven interfacial water evaporation technology. Here, we present a scalable fabrication method for porous monolithic polymer evaporators through olefin metathesis polymerization coupled with NaCl templating. The large-area evaporator (800 × 600 mm²) incorporates amine-capped aniline trimer (ACAT) as a photothermal component within a dicyclopentadiene (DCPD)/cyclooctene (COE) polymer matrix, enabling efficient solar energy absorption and water transport. The optimized SDIE PDCPD-25%COE-10%ACAT exhibits notable performance in seawater desalination, wastewater treatment, and lithium salt enrichment. Under 1 sun irradiation, it achieves a pure water evaporation rate of 3.64 kg m⁻² h⁻¹ with a solar-thermal conversion efficiency of 96.7%, reflecting high energy utilization efficiency. Outdoor experiments under natural sunlight further confirm its operational feasibility, yielding an evaporation rate of 3.33 kg m⁻² h⁻¹. This work provides a viable route for the large-scale implementation of photothermal water treatment technologies, contributing to sustainable freshwater production and resource recovery.