Lithium transport through Li1−δMn2O4 electrode involving the ordering of lithium ion by numerical analysis of current transient

Lithium transport through Li1−δMn2O4 electrode during the lithium intercalation involving the disorder to order phase transition was investigated by numerical analysis of the current transient. All the measured current transients showed non-Cottrell behaviour during the whole lithium intercalation, and the relationship between the initial current level and the applied potential drop followed Ohm’s law. The current transient was numerically simulated based upon the ‘cell-impedance controlled’ lithium transport at various applied potential steps. The current transient theoretically calculated well coincided with that transient experimentally measured in value and shape. The typical current transient showed two ‘quasi-current plateaux’ separated by a steep current drop in value, indicating the coexistence of the disordered and ordered phases, as confirmed from the concentration profile across the electrode. From the experimental and theoretical results, it was strongly inferred that lithium transport through the Li1−δMn2O4 electrode is governed by the ‘cell-impedance controlled’ constraint during the whole lithium intercalation involving the ordering of lithium ion.