VARIATION OF THE PREEXPONENTIAL FACTOR AND ACTIVATION-ENERGY FOR LITHIUM DIFFUSION IN CUBIC TITANIUM DISULFIDE

The chemical, D, and self diffusion, D, coefficients for lithium transport within the cubic polymorph of TiS2 have been determined as a function of temperature and composition by ac impedance measurements. Both D and D vary with the lithium content, reaching maxima at 23°C of 5.6 × 10-10 and 6.9 × 10-9 cm2sec-1, respectively. The Arrhenius plots for the self diffusion coefficient are linear; however, the preexponential factor and activation energy vary significantly with composition displaying a broad minimum centered at x = 0.5. This behavior is associated with interactions between the mobile ions; two possible models for ion interactions are presented, either or both of which may be important in these systems. © 1990.