Solar‐Driven Lithium Extraction by a Floating Felt

Abstract Oceans/brine offers a massive supply of lithium sources that can support the renewable energy storage system. However, the current lithium extraction processes from seawater are complicated for scalable production. Here, a high‐performance solar‐driven, direct lithium‐extraction felt (DEF) is developed. DEF consists of a reasonable addition of Li_1.6Mn_1.6O₄ particles on polypropylene/polyethylene core‐sheath fibers, which are dark‐colored and can float on top of bodies of water. Compared with the conventional method, DEF shows improved Li‐ion adsorption rate and capacity by solar‐driven. Meanwhile, the fibers’ hydrophilicity promotes spontaneous upward transport of water/ions, avoiding concentration polarization. Even for the test using simulated seawater (≈100 kg) with low Li‐ion concentration outdoors, DEF demonstrates high efficiency under natural sunlight. DEF shows good salt‐rejection performance in outdoor real‐time evaporation experiments to ensure working stability. In addition, this method saves the steps of liquid storage, liquid transportation, and pump drive. This work provides an easy, highly efficient, and low‐cost strategy to extract lithium directly from seawater/brine with the assistance of solar energy.