Electromigration separation of lithium isotopes: the competitive effect of ions

This study systematically investigates the competitive effects of H + , NH₄ + , and OH − on Li + migration and isotope separation during electromigration. Combined experimental and DFT analyses reveal that H + and NH₄ + significantly inhibit both Li + transport and isotopic partitioning, primarily through competitive chelation with 4-aminobenzo-15-crown-5, with H + exhibiting the strongest interference. DFT results confirm the binding affinity order: H +  > NH₄ +  > Li + . Additionally, OH − accumulation further impedes Li + migration and system stability. These findings highlight the critical importance of controlling electrolyte pH and minimizing competing ion concentrations, providing essential guidance for optimizing high-efficiency lithium isotope separation systems.