A complex impedance model for spherical particles was used to determine the lithium ion diffusion coefficient in graphite as a function of the state of charge and temperature. The values obtained ranged from of 1.12 x 10-10 to 6.51 x 10-10cm2/s at 25C for 0 and 30% state of charge, respectively, and for 0% state of charge, the value at 55C was 1.35 x 10-10cm2/s. The conventional potentiostatic intermittent titration technique and Warburg impedance approaches were also evaluated, and the advantages and disadvantages of these techniques were exposed.

Determination of the Lithium Ion Diffusion Coefficient in Graphite. Yu, P., Popov, B.N., Ritter, J.A., White, R.E.: Journal of the Electrochemical Society, 1999, 146[1], 8-14