Electrochemical AC-Impedance Spectroscopy

The diffusion coefficient of lithium ions in the intercalation electrodes also can be measured, using EIS, by the analysis of Warburg impedance representing diffusion through the electrode with I.C. in Equation (5.28), impermeable B.C. in Equation (5.29), and sinusoidal oscillation B.C. 

The Warburg coefficient can be experimentally determined from the average value for the slope ofthe Z versus co plot, and for the slope of the -Z versus co plot. In many reports, the diffusion coefficients of lithium ions have been determined for various transition metal oxides [13, 97, 113, 114] and graphite [59] electrodes by using EIS. 

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