Abstract
We have carried out nuclear magnetic resonance (NMR) studies on a new class of electrolyte consisting of a lithium salt (LiMPSA) and a macrocycle ([2.2.2] cryptand). NMR diffusion coefficient measurements have determined the motion of lithium cations polyatomic anions (MPSA) and encapsulating macrocycles with the striking result that they are equal over a large temperature range. Diffusion coefficients as low as have been measured through the use of a 42 T/m fringe-field gradient. The magnitudes of the anion and cryptand diffusion were found to be consistent with a free-volume picture for translational diffusion. The transport of the lithium cations was interpreted as taking place mainly through association with large anions (MPSA) and encapsulating macrocycles ([2.2.2] cryptand), with averaged residence time fractions of 77 and 23 %, respectively. NMR spin-lattice relaxation time measurements of and spins have also been performed.
- Received 6 November 2000
DOI:https://doi.org/10.1103/PhysRevB.64.214201
©2001 American Physical Society