10.1021/jp300085n.s001 Gosuke Oyama Gosuke Oyama Yuki Yamada Yuki Yamada Ryu-ichi Natsui Ryu-ichi Natsui Shin-ichi Nishimura Shin-ichi Nishimura Atsuo Yamada Atsuo Yamada Kinetics of Nucleation and Growth in Two-Phase Electrochemical Reaction of Li<sub><i>x</i></sub>FePO<sub>4</sub> American Chemical Society 2012 KJMA phase transition proceeds electrode movement LixFePO 4The kinetics LixFePO 4 chronoamperogram 2012-04-05 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Kinetics_of_Nucleation_and_Growth_in_Two_Phase_Electrochemical_Reaction_of_Li_sub_i_x_i_sub_FePO_sub_4_sub_/2534584 The kinetics of a two-phase electrochemical reaction in Li<sub><i>x</i></sub>FePO<sub>4</sub> was investigated by potential-step chronoamperometry under various experimental conditions: amplitude of potential step, direction of potential step, particle size, and thickness of composite electrodes. Only under a small potential step (10 mV) applied to large Li<sub><i>x</i></sub>FePO<sub>4</sub> particles (203 nm), the chronoamperogram showed a momentary current increase, followed by gradual decline, indicating that the nucleation and growth governed the electrode kinetics. In that condition, the chronoamperogram was analyzed with the Kolmogorov–Johnson–Mehl–Avrami (KJMA) model, which describes the kinetics of phase transition. The obtained Avrami exponent of ca. 1.1 indicates that the phase transition proceeds with a one-dimensional phase-boundary movement, which is consistent with the previously reported mechanism. From the temperature dependence of the obtained rate constant, the activation energy of the phase-boundary movement in Li<sub><i>x</i></sub>FePO<sub>4</sub> was estimated to be 42 and 40 kJ mol<sup>–1</sup> in cathodic and anodic reactions, respectively.