Determination of lithium ion transference numbers by electrophoretic nuclear magnetic resonance

Lithium ion transference numbers (T-Li) have been determined for some aqueous gel electrolytes by electrophoretic NMR (ENMR). This method is essentially a rapidly detected Hittorf method, in which the positions of nuclei are labeled by the phase of the NMR signal and the mobility of the nuclei is determined from the phase shift of the signal in a stimulated echo experiment with a synchronized electric field pulse. The work presented is a proof-of-concept of the application of the ENMR method to lithium ion transference measurements for several different lithium salts in gelled electrolytes. The NMR method allows accurate determination of T-Li values, as indicated by the similarity of T,in the gelled electrolytes to those in aqueous electrolyte solutions of the same salt concentration.