Self-Intercepting Interference of Hydrogen-Bond Induced Flexible Hybrid Film to Facilitate Lithium Extraction

Supported lithium-ion sieve (LIS) adsorbents have received widespread attention for their inherent adsorption potential toward lithium (Li) from liquid Li source. However, LIS-based adsorbents still suffer from slow Li extraction rate and reduced Li selectivity caused by the embedding of the active sites and the adverse effects of high level of competing ions from seawater/brine. Here, relying on hydrogen bond (O–Mn–O···H–O) interaction, a LIS-based sandwich heterostructure is designed by stably confinement of 0D MnO2·0.3H2O (HMO) nanoparticles into the interlayer of a flexible 2D MXene/1D cellulose nanofiber (MC) hybrid film (HMO@MC). Benefiting from the strong hydrogen bond interaction, the HMO@MC hybrid film achieves an excellent LIS utilization (up to 96%) with a maximum Li adsorption capacity of 21.39 mg g-1, outperforming most LISbased adsorbents. More impressively, the HMO@MC heavily reduces the Li migration barrier by self-intercepting interference through steric hindrance effect of surface functional groups, thus obtaining a fast Li adsorption rate (18.23 mg g-1 HMO, 12 h) and a super-high Li selectivity (e.g., Li/Na of 29231.8 and Li/Mg of 3605.9). This work offers a new adsorbent designing idea for lithium extraction from liquid lithium source and will inspire more efforts in constructing LIS-based adsorbents for Li recovery with improved Li recovery performance.