A Mangrove-Inspired Off-Grid System Integrating Electrodialysis and Photothermal Evaporation for Direct Lithium Salt Extraction from Brine

The growing demand for lithium necessitates sustainable extraction technologies that overcome the high energy consumption and geographical constraints of traditional evaporation and chemical precipitation. Here, we report the first mangrove-inspired photothermal–electrodialysis (PT–ED) system that achieves self-sustained, selective, and direct lithium salt extraction using only solar energy. The system integrates photo–electro–thermal (PET) coupling, where sunlight-driven photothermal evaporation and internally generated electric fields synergistically regulate ion migration and water removal within a single continuous process. This coordinated field interaction enables directional Li⁺ transport and controlled crystallization while preventing membrane fouling and parasitic salt deposition. Structural optimization of the leaf-shaped PT interface and an Li0.33La0.56TiO3 (LLTO)-based Li+-selective membrane ensures sustained operation and high selectivity. The PT–ED system delivers a Li+ flux of 9.6 mg m-2 h-1 and Li+/Mg2+ selectivity above 800, maintaining stable performance over 72 h and across brines collected from different salt lakes. This bioinspired PET approach offers a scalable pathway toward solar-driven, off-grid lithium recovery, establishing a universal framework for sustainable ion extraction, solar desalination, and circular water–energy utilization.