In situ growth preparation of bio-inspired Al-based Li+ Sieve Membranes for Sustainable Li-extraction from Original Brines

Lithium, a critical metal for green energy storage, is in surging global demand, yet its extraction from salt-lake brines with high Mg 2+ /Li + ratios faces severe technical and ecological challenges ( e.g. , low selectivity, acid washing-induced environmental damage). Herein, a bio-inspired Li + sieve membrane was developed by in situ growing Li–Al layered double hydroxide (Li/Al-LDH) on polyacrylonitrile (PAN) supports, addressing the above bottlenecks for sustainable Li-extraction from original brines. Integrated into a flat-sheet membrane module, the LDHs@PAN membrane exhibited exceptional Li-extraction performance with high Li + selectivity, rapid adsorption kinetics, and outstanding regenerability in real high Mg 2+ /Li + brine. The in situ grown LDHs form a robust organic-inorganic interface, which not only enhances the areal adsorption capacity and cycling stability but also enables fast on-site reconstruction of the degraded membrane. Notably, the membrane realizes Li + desorption via simple water washing (no acid usage), protecting the fragile ecological environment of salt-lake areas. This work provides an eco-friendly and scalable strategy for lithium recovery from original brine, supporting the sustainable supply of lithium for green energy systems and overcoming the fundamental limitations of industrial Al-based absorbents.