Separation of lithium isotopes: Electromigration coupling with crystallization

6 Li and 7 Li, two natural isotopes of lithium, play an important role in the nuclear industry. Here, a system of ionic liquid-crown ether was fabricated for lithium isotope separation and the 6 Li isotope separation coefficient can reach 1.406 that showing a good prospect for lithium isotope separation by this method of electromigration. Interestingly, the single crystal containing crown ether and lithium, in which 7 Li was enriched, was obtained from the experiments. It is contrary to popular wisdom and can be attributed to the steric hindrance effect. This provides a new route to separate lithium isotopes, that is electromigration coupling with crystallization.