The kinetics of lithium transport through Li1-delta CoO2 thin film electrode by theoretical analysis of current transient and cyclic voltammogram

Abstract

Lithium transport through lithium cobalt dioxide thin film electrode prepared by rf-magnetron sputtering was investigated in a 1 M solution of LiClO4 in propylene carbonate (PC) by means of analysis of current transient and cyclic voltammogram. All the experimental current transients in shape deviated markedly from the Cottrell behaviour, and the cathodic current transients intersected the corresponding anodic current transients each other. Moreover, the relation between initial current level and applied potential step followed Ohmic law. The current transient was simulated as a function of applied potential by means of the numerical analysis underlain by the 'cell-impedance controlled' lithium transport. The numerically simulated current transients coincided quantitatively almost with those current transients experimentally determined. The cyclic voltammograms theoretically obtained at various scan rates under the assumption of the 'cell-impedance controlled' lithium transport, were also quantitatively in good agreement with those cyclic voltammograms experimentally measured. (C) 2001 Elsevier Science B.V. All rights reserved.