Chronoamperometric studies of the stage 2 (LiC12) to stage 1 (LiC6) transition during electrochemical insertion of Li ions into graphite electrodes showed 5 distinct domains in their current vs. time curves. A linear increase of current at the beginning of domain II and a decrease in current with time within domain IY were identified with two-dimensional instantaneous nucleation of cylindrical grains of stage 1 into stage 2, their growth and further coalescence with the formation of the continuous moving boundary. We could calculate the following characteristic parameters: the nucleation time constant, tau(n) = 990 s; the density of nucleation sites N-o = 2.5 x 10(8) cm(-2), the velocity of the lateral growth of cylindrical nuclei, a = 3.6 x 10(-8) cm s(-1) and the thickness of the nucleation layer, d = 0.36 Pm. After nucleation stage, the interphase propagates initially linearly with time and then proportionally to the square root of time (domain IV). At 30 degrees C the speed of propagation of the moving boundary between stage 1 and stage 2, d xi/dt', is around 1.6 x 10(-7) cm s(-1). The activation energies of a, d xi/dt' and D-1 obtained from the related Arrhenius plots were found to be 0.13, 0.19 and 0.23 eV, respectively. (c) 2005 Elsevier B.V. All rights reserved.