Graphene oxide (GO)-based membranes (GOMs) hold great promise for electrochemical Li+ separation due to their exceptional water permeability and ion selectivity. However, their application is limited by the interlayer swelling and poor stability in aqueous solutions. Here we report a heteroatomic sol-reinforcing dot (HARD) strategy using aluminosilicate (AS) sols as physical crosslinkers. Subnanometer-sized AS sols are inserted into GO interlayers to create percolated AS gel networks that improve the swelling resistance and hydration stability. AS sols neutralize/stabilize the negatively charged GO interlayers with tunable positive charges from Si-O-Al motifs, allowing precise tuning of interlayer spacing. The fabricated AS/GOMs show remarkably enhanced stability and lithium-ion selectivity over various metal ions (Ni2+, Co2+, Mn2+, and Fe3+) compared to unmodified GOM under H-type cell experiments. Furthermore, the optimal AS/GOM is applied to a continuous redox-mediated electrodialysis system, achieving a record-high Li+ permeation of 2.0 mol m−2 h−1 and Li+/Fe3+ selectivity of 42. Considering a variety of heteroatom combinations and the ease of sol-gel processing, this approach allows the development of robust GOMs for diverse separation applications.
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) ( 2021R1C1C1009988 ), Global - Learning & Academic research institution for Master's\\u00B7PhD students, and Postdocs (G-LAMP) Program of the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education (No. RS-2023-00285390 ), and H2KOREA funded by the Ministry of Education (2022Hydrogen fuel cell-002, Innovative Human Resources Development Project for Hydrogen Fuel Cells).
