An Induced Li⁺ Oriented Migration Strategy for High-Efficiency Extremely Strong Acid Lithium Recovery

Conventional lithium extraction methods exhibit limited efficiency in strongly acidic solutions. This study developed a brand-new and universal lithium recovery strategy from strongly acidic systems using Li⁺ migration between directionally formed solid phase of lithium-aluminum layered double hydroxides (Li/Al-LDHs) and alternate aqueous solutions. Li⁺ ions in strongly acidic solutions with massive coexisting cations (Na⁺, K⁺, Fe²⁺, Ca²⁺, Mg²⁺, Al³⁺, etc.) were inductively converted into the solid precipitate through a precise crystal phase regulation. A non-equilibrium thermodynamic model was developed and revealed that the lithium deintercalation flux exhibited a linear dependence on the chemical potential gradient, systematically elucidating the critical parameters governing extraction efficiency. Subsequently, lithium extraction from Li⁺-enriched solid could be accomplished easily using neutral aqueous solutions with a complete delithiation, and the overall lithium recovery from acidic systems exceeded 96% with the residual solid recycling process and waste-free disposal. Furthermore, the lithium extraction strategy was proven applicable in authentic multi-component acidic solutions with efficient lithium recovery and low costs. This work is expected to significantly promote the development of universal extreme system lithium separation technology.