Elementary Analysis of Impedance Spectra

To investigate the elementary reaction steps and their contribution to the total intercalation process, impedance spectra for the fresh and aged cells were obtained as shown in Figure 10. The impedance spectra consisted of semicircles and an inclined line. Although a semicircle typically results ficm the interfacial reactions and an inclined line is attributable to the solid-state diffusion process, the overlapping of the time constants of the reactions in the anode and cathode makes reliable mechanism-based analysis of the impedance spectra quite unlikely. 

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