COMPARISON OF THE CUBIC AND LAYERED POLYMORPHS OF TITANIUM DISULFIDE

Lithium intercalation into the three hosts, layered stoichiometric TiS2, layered non-stoichiometric Ti1.09S2 and cubic TiS2-C, are compared. It is shown that the variation of open circuit voltage with lithium content for TiS2-C may be described by an equation first derived for concentrated electrolyte solutions. Data on the diffusion of lithium in each host is extracted from ac measurements. The composition dependence of the pre-exponential factor and activation energy for the self diffusion of lithium ions is presented. Broad minima are noted in each of the plots and discussed in terms of interactions between the guest charges. It is shown that the data are consistent with significant changes in the concentration of mobile lithium ions rather than changes in their mobility alone.