DYNAMICS OF LITHIUM IONS IN SPINEL-TYPE (LI2MNCL4)-LI-7

In order to determine the mechanism of the high ionic conductivity of inverse spinel-type Li2MnCl4, quasielastic neutron scattering measurem ents (incident wavelength 0.418 nm) of a (Li2MnCl4)-Li-7 single crysta l as a function of temperature (360; 428 and 552 K), and momentum tran sfer Q have been performed. The observed quasielastic intensity depend s on temperature but hardly not on Q within the accessible range from 3.0 to 19.5 nm(-1). In particular, there is no indication fbr anisotro pic behaviour. The data is interpreted as local motion of the Lithium ions. The long-range translational motion of lithium ions causing the ionic conductivity takes place on a much longer time-scale and cannot be resolved under the present experimental conditions. (C) 1998 Elsevi er Science B.V. All rights reserved.