Lithium transport through Li1+delta[Ti2-yLiy]O-4 (y=0; 1/3) electrodes by analysing current transients upon large potential steps

Lithium transport through Li1+delta[Ti2-yLiy]O-4 (y = 0; 1/3) electrodes in the coexistence of a Li-poor phase alpha and a Li-rich phase beta was inve stigated during electrochemical lithium intercalation by using the potentio static current transient technique under large potential stepping. For this purpose, the galvanostatic charge-discharge curve and the cathodic current transient were obtained as functions of the lithium content (1 + delta) an d the lithium injection potential, respectively. The charge-discharge curve showed a potential plateau due to the coexistence of two phases alpha and beta. The values of the quasi-equilibrium potential and the corresponding s toichiometry of the alpha- and beta-phases were determined from the potenti al plateau. A three-stage current transient was observed as the applied pot ential step went below the potential plateau, and the second stage of this current was found to be governed by the diffusion-controlled phase boundary movement between the alpha- and beta-phases. (C) 1999 Elsevier Science S.A . All rights reserved.