Controllable Synthesis of Organic-Cladding Li/Al-LDH and Its High Cycling Performance for Lithium Extraction from Salt Lakes

Lithium/aluminum layered double hydroxides (Li/Al-LDHs) have been widely studied for lithium extraction due to their favorable adsorption capacity and outstanding ion selectivity; however, practical applications are limited by the difficulty of SO 4 2– intercalation–induced lithium desorption and structural delamination. In this study, siloxane networks after hydrolysis and polymerization of methyltrimethoxysilane (C 4 H 12 O 3 Si) were employed as cladding layers to cover the surfaces of Li/Al-LDHs, aiming to suppress SO 4 2– intercalation and enhance the structural integrity, thereby mitigating delamination. The resistance effect is positively correlated with the thickness of the cladding layer. The adsorption capacity of the optimal sample after 8 cycles was increased by 50% compared to the pristine Li/Al-LDH. Additionally, its separation coefficients for Li/K, Li/Na, and Li/Mg─specifically 50.82, 50.47, and 149.74─significantly outperformed those of pristine Li/Al-LDH.