Lithium intercalation and deintercalation of thermally decomposed LiAl₂-layered double hydroxides

Lithium aluminum layered double hydroxide (LiAl₂-LDH) nanocrystals on aluminum metal substrates were synthesized to adsorb lithium in aqueous solutions and utilized to collect lithium in aqueous media. LiAl₂-LDH is transformed at 300 °C into a mixture of LiCl and Li-Al-O-OH; dissolved lithium in deionized water at 25 °C reached 85% compared to the intercalated lithium content. Amorphous Li-Al-O-OH residues on the aluminum metal substrate were capable of adsorbing lithium ions back to the lithium rich LiAl₂-LDH phase. Thermal treatment followed by additional lithium intercalation suggested a topotactic reaction of lithium ions between amorphous Li-Al-O-OH and LiAl₂-LDH. We also proposed a facile recycling method of lithium ions by peeling off the Li-Al-O-OH layer to save the aluminum metal substrate.