Enrichment of lithium from seawater and brines by forward osmosis: progress and prognosis

The escalating demand for lithium, driven primarily by its critical role in energy storage technologies, necessitates a stable and resilient supply chain. At present, lithium production is concentrated in a limited number of countries, which heightens supply-chain vulnerability for Li-ion battery manufacturers. To mitigate this risk, a systematic exploration of feasible alternative lithium sources has become imperative. Seawater and various natural brines represent vast and largely untapped lithium reservoirs, provided that key technical challenges can be effectively addressed. Despite the complexities arising from lithium’s unique aqueous chemistry and interference from coexisting ions, sustained research and technological development efforts are underway. This review presents an updated and comprehensive perspective on lithium recovery, with particular emphasis on forward osmosis, both as a stand-alone process and in synergistic combination with other separation technologies. Critical challenges related to draw solution formulation and regeneration, mitigation of reverse solute flux, feed pretreatment strategies, membrane functionalization, and fouling control are systematically examined. In addition, key techno-economic considerations governing the feasibility and scalability of FO-based lithium recovery processes are discussed.