The kinetics of lithium transport through LiNiO 2 by current transient analysis

Abstract

The kinetics of lithium transport through Li 1− δ NiO 2 have been investigated in a 1 M solution of LiClO 4 in propylene carbonate using current transient technique. All the cathodic and anodic current transients experimentally measured hardly follow the Cottrell behaviour. From the linear relationship between initial current level in current transient and applied potential step, ‘cell-impedance’ was determined as a function of the electrode potential. ‘Cell-impedance’ with the electrode potential calculated from the current transient, is similar in value to that of internal cell resistance composed of solution resistance, contact resistance, and absorption resistance obtained from the Nyquist plot. Taking the variation of ‘cell-impedance’ with the electrode potential into account, the lithium transport through the Li 1− δ NiO 2 electrode was theoretically analysed by means of numerical simulation of the current transient under the assumption of the ‘cell-impedance controlled’ lithium transport. The current transients theoretically calculated quantitatively shared well those experimentally measured. Lithium transport through the Li 1− δ NiO 2 electrode being even degraded by jumping the electrode potential to the value higher than 4.20 V Li/Li + , proceeds under the ‘cell-impedance controlled’ constraint.