Carbonate-intercalated aluminum layered double hydroxide for high-capacity lithium extraction

Aluminum-based lithium adsorbents (Li-Al LDHs) were a way to sustainable lithium extraction from aqueous resources. Despite advantages like acid-free regeneration and environmental benignity, their low lithium adsorption capacity remained a major limitation. Based on the Thinking of interlayer anion modification, density functional theory (DFT) simulations was used to predict interlayer spacing and deintercalation energy for common anions in aluminum-based clusters. And experimental validation was performed by intercalating CO₃ 2− anion into the adsorbent. CO₃ 2− anion insertion effectively expanded interlayer spacing and facilitated Li + diffusion; systematic characterization confirmed its successful incorporation into the Li-Al LDH framework. Adsorption experiments demonstrated that the Li + adsorption capacity was significantly enhanced compared with conventional Li-Al LDHs. Stability and selectivity were also investigated in the study. Anion intercalation improved Li-Al LDH capacity, deepened understanding of the structure-performance relationship of lithium adsorbents, and offered potential for scalable lithium recovery from brines and seawater. • DFT applied to the molecular structure design of aluminum based lithium adsorbents. • The CO 3 2− intercalated Li-Al-CO 3 LDH was synthesized by a hydrothermal method. • Under optimal conditions, the adsorption capacity of Li-Al-CO 3 LDH was 18.3 mg/g. • The separation factor between lithium and magnesium reached a significant value of 118.4. • The adsorption capacity remained above 95 % of the initial value after 30 cycles.