The kinetics and thermodynamics of electrochemical intercalation of lithium into Li WO with a hexagonal tungsten 0.50 3.25 bronze structure prepared by a solution technique were studied with an ac impedance method, open-circuit potential and X-ray diffraction measurements. The open-circuit-potential versus x-in-Li [Li WO ]-curve consists of two straight lines x 0.50 3.25 with different slopes, which were related to the structural variation in the oxide with lithium intercalation. The standard 0 Gibbs energy for lithium intercalation, DG , was 2 252.6 kJ / mol in the range from x to 1 in Li [Li WO ] at 258C. The I x 0.50 3.25 chemical diffusion coefficients, D, of lithium intercalation into oxide, were measured by ac impedance method as functions Γ΅f depth of lithium intercalation and temperature in 1 M LiClO / propylene carbonate solution. The calculated D values were 4 29 2
of the order of 10 cm / s and the activation energy for lithium diffusion was 35-44 kJ / mol, being typical of diffusion in layered intercalation materials. Furthermore, the lithium diffusion coefficient and the activation energy for lithium diffusion 1 1
in Li WO were compared with hexagonal WO and hexagonal-type A WO (n 5 0.14-0.28, A 5 Na , K , 0.50 3.25 3 n 31n / 2 1 NH ).