Mechanisms of lithium transport through transition metal oxides studied by analysis of current transients

Abstract

Lithium transport through such transition metal oxides as Li1+delta[Ti5/3Li1/3]O-4, Li1-deltaNiO2 and LideltaV2O5 was investigated by analysis of current transients. All the experimental current transients in shape deviated markedly from the Cottrell character during the whole intercalation/deintercalation, and the initial current level varied linearly with the applied potential step according to Ohm's law. Moreover, it was observed that the current transient during phase transformation is characterised by a 'current plateau'. The current transient was simulated as a function of applied potential by numerical analysis assuming 'cell-impedance-controlled' lithium transport. The numerically simulated current transient featured quantitative behaviour characteristic of non-Cottrell behaviour and exhibited a 'current plateau'. The lithium transport mechanism through the oxides is discussed in terms of 'cell-impedance-controlled' intercalation/deintercalation. (C) 2001 Elsevier Science Ltd. All rights reserved.