In order to determine the mechanism of high ionic conductivity in this inverse spinel, quasi-elastic neutron scattering measurements (incident wavelength 0.418nm) were made of a 7Li2MnCl4 single crystal at 360, 428 or 552K. The momentum transfer, Q, was also determined. It was found that the observed quasi-elastic intensity depended upon temperature, but hardly at all upon Q, within the accessible range from 3.0 to 19.5/nm. There was no indication of anisotropic behavior. The data were explained in terms of the local motions of the Li ions. The long-range translational motion of Li ions, which caused the ionic conductivity, occurred on a much longer time-scale and could not be resolved under these experimental conditions.

Dynamics of Lithium Ions in Spinel-Type 7Li2MnCl4. G.A.Eckstein, G.Eckold, W.Schmidt, H.J.Steiner, H.D.Lutz: Solid State Ionics, 1998, 111[3-4], 283-7