biostudies-literatureBao SNatural Science Foundation of Shandong Province (Shandong Provincial Natural Science Foundation)Natural Science Foundation of Shandong ProvinceNational Natural Science Foundation of ChinaNational Natural Science Foundation of China (National Science Foundation of China)3896https://www.ebi.ac.uk/biostudies/studies/S-EPMC12022084biostudies-literatureUnknown16(1)Certain biological channels exhibit remarkable selectivity, effectively distinguishing between competing cations. If artificial membranes could achieve similar precision in differentiating competing ions from Li⁺, it could advance sustainable technologies in lithium extraction. In this study, we present a covalent organic framework (COF) membrane featuring a randomly oriented structure that enables selective separation of major competing ions from Li⁺. The random orientation results in narrow pores, which impart size-based selectivity among alkaline ions. Additionally, the COF incorporates sulfonic groups that preferentially bind to Na⁺ and K⁺, facilitating their transport while retaining Li⁺. These synergistic mechanisms endow the memNature communicationsRandomly oriented covalent organic framework membrane for selective Li<sup>+</sup> sieving from other ions.PMC12022084ZR2023MB0375227303622272194ZR2021YQ12Liu XYu LXia JSong SGao JMa ZLi QSui KBao SZhao YfalseRandomly oriented covalent organic framework membrane for selective Li<sup>+</sup> sieving from other ions.Certain biological channels exhibit remarkable selectivity, effectively distinguishing between competing cations. If artificial membranes could achieve similar precision in differentiating competing ions from Li⁺, it could advance sustainable technologies in lithium extraction. In this study, we present a covalent organic framework (COF) membrane featuring a randomly oriented structure that enables selective separation of major competing ions from Li⁺. The random orientation results in narrow pores, which impart size-based selectivity among alkaline ions. Additionally, the COF incorporates sulfonic groups that preferentially bind to Na⁺ and K⁺, facilitating their transport while retaining Li⁺. These synergistic mechanisms endow the mem2025-01-01T00:00:00Z2025 Apr2025-07-01T03:05:45.013Z2025-07-01T03:05:45.013ZS-EPMC120220844027480310.1038/s41467-025-59188-1