Two expressions were introduced to calculate the lithium ion diffusion coefficients in graphite anode as a function of potentials when potentiostatic intermittent titration technique was used. The lithium ion diffusion coefficients in graphite derived from effective surface area, which was measured by electrochemical method, were more reliable than those derived simply from radius of graphite particles. The curves of dQ/dE versus E demonstrated that there were three reversible phase transitions during intercalation or de-intercalation of lithium ion in graphite. In the vicinity of the potentials where phase transitions take place, the lithium ion diffusion coefficients in graphite material have three minima in the potential range 10 ∼ 600mV.

Determination of the Lithium Ion Diffusion Coefficient in Graphite Anode Material. Tang, Z.Y., Xue, J.J., Liu, C.Y., Zhuang, X.G.: Acta Physico - Chimica Sinica, 2001, 17[5], 388