A directional growth strategy for high layer charge <scp>Li</scp>/<scp>Al‐LDHs</scp> to reinforce <scp>Li<sup>+</sup></scp> extraction in low‐grade salt lake brines
Jun Chen, Cheng Lian, Jianguo Yu, Sen Lin
Abstract
Abstract Novel Li/Al‐LDHs with high layer charges (HCLDHs) were synthesized in the light of the inter‐layer effect on Li + adsorption. Compared with conventional low‐charge Li/Al‐LDHs (LCLDHs), HCLDHs exhibited a distinct micromorphology characterized by a preferential growth orientation along the c ‐axis and a significantly reduced lateral diameter. Adsorption experiments showed that HCLDHs possessed superior Li + adsorption performance in various brines, specifically with a Li + adsorption capacity of 9.72 mg/g in Qarhan old brine, surpassing that of LCLDHs by 2 mg/g. All‐around characterizations and finite element analysis calculations uncovered that the reduced lateral dimensions facilitated the exposure of more accessible Li + adsorption sites, while the high positive charge of the host layers decreased the electrostatic repulsion toward Li + by attracting anions and increased the surrounding ionic strength. Surface photovoltage (SPV) and x‐ray absorption fine structure (XAFS) further proved the structural stability of HCLDHs, which ensured the maintenance of a high Li + adsorption capacity during adsorption–desorption cycles.