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 SO42– intercalation–induced lithium desorption and structural delamination. In this study, siloxane networks after hydrolysis and polymerization of methyltrimethoxysilane (C4H12O3Si) were employed as cladding layers to cover the surfaces of Li/Al-LDHs, aiming to suppress SO42– 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.