Lithium isotope effects upon electrochemical lithium insertion to host material from ionic liquid medium

Lithium was electrochemically inserted from a Li+ ion containing ionic liquid into graphite or tin to observe lithium isotope effects that accompanied the insertion. While no preferential uptake of the lithium isotopes was detected with graphite, the lighter isotope, 6Li, was preferentially fractionated into tin with the single-stage lithium isotope separation factors, S, ranging from 1.004 to 1.008 at 25 °C. It was speculated that a Li+ ion was inserted into graphite together with an anionic component of the ionic liquid and, upon the reduction of the Li+ ion to a lithium atom, the anion was released from graphite, while a Li+ ion alone was inserted into tin. Molecular orbital calculations supported this speculation in a qualitative fashion.