Recent progress in metal-based lithium-ion sieves for adsorption-driven direct lithium extraction

초록

The rapid growth of electric vehicles, renewable energy technologies, and grid-scale energy storage has intensified global lithium demand, highlighting the urgent need for efficient, selective, and sustainable lithium extraction technologies. Adsorption-based direct lithium extraction (DLE) has emerged as a promising alternative to conventional evaporation because of its high Li+ selectivity, operational simplicity, lower environmental footprint, suitability for complex aqueous resources, and strong scalability potential. Inorganic metal-based lithium-ion sieve (LIS) adsorbents, particularly lithium manganese oxides (LMOs), lithium titanium oxides (LTOs), and lithium-aluminum layered double hydroxides (Li/Al-LDHs), are among the most promising adsorbents because of their ion-sieving ability, structural-memory effect, and selective Li+ uptake from brines with low Li+ concentrations and high Mg2+/Li+ ratios. However, each LIS family exhibits distinct limitations. LMO-type sieves offer high Li+ capacity and fast exchange through spinel vacancies but suffer from Mn3+-driven Jahn-Teller distortion and Mn dissolution. LTOtype sieves exhibit superior acid resistance and framework durability through strong Ti-O bonding, yet their rigid structures restrict Li+ transport and slow adsorption/desorption kinetics. Li/Al-LDHs are closer to practical deployment because of mild regeneration and process compatibility, but their lower capacity, hydration-sensitive interlayers, anion co-intercalation, and gibbsite-like Al(OH)3 formation limit long-term stability. This review critically summarizes recent advances in LMO-, LTO-, and Li/Al-LDH-type LISs, emphasizing synthesis, shaping, modification, adsorption/desorption performance, regeneration, and scale-up challenges. A structure-property-stability framework is proposed to guide next-generation LIS design. This framework links host structure, Li+ transport pathways, adsorption/desorption behavior, regeneration chemistry, and degradation mechanisms with selectivity, kinetics, cycling durability, and process readiness.

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