The dependence of the chemical diffusion coefficient of Li ions, in spinel cathode material, upon electrochemical cycling was investigated by using the capacity intermittent titration technique. The results showed that there were 2 minimum peaks in the curves of D ≈ E, at ≈3.95 and ≈4.12V in the voltage range from 3.85 to 4.30V. The curves of D ≈ E at different cycles exhibited an interesting phenomenon in that the values of D tended to increase with cycling numbers. This phenomenon indicated an enhanced diffusion of Li-ions in LiMn2O4 cathode material, induced by electrochemical cycling.

Phenomenon of Enhanced Diffusion of Lithium-Ion in LiMn2O4 Induced by Electrochemical Cycling. X.C.Tang, L.Q.Li, B.Y.Huang, Y.H.He: Solid State Ionics, 2006, 177[7-8], 687-90