A structural model to calculate the electrochemical interface area for a composite graphite electrode was described. A new equation using the model predicted area to calculate the chemical diffusion coefficient (DLi+) eliminated the effects of fabrication such as active mass (mB) and geometrical area (SGeo). The chemical diffusion coefficient values calculated for graphite electrodes of different thicknesses and porosities by using the new equation were almost the same as expected. The values of DLi+ in the graphite varied between 10–11.9 and 10–9.9cm2/s over the course of Li de-intercalation in the graphite samples.

Evaluation of Electrochemical Interface Area and Lithium Diffusion Coefficient for a Composite Graphite Anode. H.Yang, H.J.Bang, J.Prakash: Journal of the Electrochemical Society, 2004, 151[8], A1247-50