High‐Flux Selective Lithium Sieving Membranes via Amorphous Ni(OH) ₂ Nanosheet Intercalation on Graphene Oxide

A tailored asymmetric membrane, denoted AM‐a‐Ni(OH) 2 NS@GO, was fabricated by integrating amorphous Ni(OH) 2 nanosheets into graphene oxide (GO) layers. The architecture enables the simultaneous enhancement of Li + selectivity and transmembrane flux via precise regulation of interlayer spacing and surface charge. The asymmetric design comprises a compact sieving layer for ion discrimination coupled with a hybrid adsorption layer to facilitate efficient mass transfer. The amorphous Ni(OH) 2 nanosheets introduce abundant oxygen vacancies, thereby selectively trapping divalent cations while ensuring stable interlayer spacing. During electrodialysis testing using simulated brine, AM‐a‐Ni(OH) 2 NS@GO demonstrates a Li + flux of 90 mmol·m −2 h −1 and a Li + /Mg 2+ selectivity ratio of 37, significantly surpassing the performance of commercial Nafion membranes and pristine GO counterparts. This study establishes a promising strategy for sustainable lithium extraction from complex aqueous resources.