DISSERTATION

________________________________________________________________ Experimental Work
change during the experiment. Furthermore, since the interpretation becomes much more
complicated for non-linear systems, it is important to perform EIS experiments in a quasi-linear
regime for electrochemical systems (Figure 5.8). This condition determines the amplitude of
the applied AC potential since a smaller amplitude results in a more linear system. Depending
on the system, E AC is typically between 1 to 10 mV.
Table 5.2. Common electrical elements and equivalent electrical circuits, their impedance
and corresponding Nyquist plots.
Equivalent electrical circuit Impedance Nyquist plot
Z = R
Z =
1
jωC
Z = R −
j
ωC
1
Z = 1 R + jωC
EIS data are generally analyzed by fitting to an equivalent electrical circuit. Electrical elements
commonly used for the construction of equivalent electrical circuits are resistor, capacitor,
constant phase element and Warburg impedance. When designing an equivalent electric circuit
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