Electrochemical Impedance Spectroscopy of a LiFePO4/Li Half-Cell

M. Cugnet[1], I. Baghdadi[1], M. Perrin[1]
[1]INES - CEA, Grenoble, France

This study demonstrates that a multiphysics model of a LiFePO4/Li half-cell can be applied to simulate the impedance results from an EIS. However, it implies that the double layer capacitance has to be taken into account, since it is responsible of the semi-circle in the impedance spectrum. A 15 min simulation allows getting a complete spectrum of the half-cell impedance from 0.1 to 200 kHz. The methodology used to adjust the three key parameters used to fit the experimental data is described. However, this work is still in progress, so we do not know exactly yet what is actually responsible of the slope observed at lower frequencies.