To my knowledge, ZSimoWin works best with three columnar dataset of 1) frequency 2) Real Z and 3) Imaginary Z. You can simply paste this dataset using the paste button or open a text file with that data as mentioned before.. Afterwards you will see your measured spectrum in the Nyquist plot. Datafitting is very easy using the Datafit button next to the paste button where you can chose the fit model or just type it, using serial R, C, Q or W elements for serial equivalent circuits and brackets for parallel equivalent circuits. E.g. R(RQ)Q represents an ohmic resistor in series to a parallel RQ circuit and a warburg element. This will be suitable to a solid ion conductor with blocking electrodes for instance. After fitting, a par file is created where you can find the parameters and the fitting errors.
You will save your data file (from your potentiostat) as *.z file :Data-->export--> z file
depending on your type of the potentiostat
Then, you open Zsimpwin software and press open and select the just saved file, you will see that your data has been drawn, after that you should select the suitable equivalent circuit and finally you will obtained your equivalent circuit parameters values and also the fitting plots.
The diameter of the semi-circle on the Nyquist plot gives the value of charge-transfer/polarization resistance. The diameter of the semi-circle is obtained exactly from the fitting using the Zsimpwin software.
To my knowledge, ZSimoWin works best with three columnar dataset of 1) frequency 2) Real Z and 3) Imaginary Z. You can simply paste this dataset using the paste button or open a text file with that data as mentioned before.. Afterwards you will see your measured spectrum in the Nyquist plot. Datafitting is very easy using the Datafit button next to the paste button where you can chose the fit model or just type it, using serial R, C, Q or W elements for serial equivalent circuits and brackets for parallel equivalent circuits. E.g. R(RQ)Q represents an ohmic resistor in series to a parallel RQ circuit and a warburg element. This will be suitable to a solid ion conductor with blocking electrodes for instance. After fitting, a par file is created where you can find the parameters and the fitting errors.
Above is correct. You just need to open your file in Zsimpwin, and applied a simulated mode to do the calculation. The radius of the cycle is the Rct. All Rct, Re, W can be obtained if you apply the proper mode. You may also get the value from Bode figure. But simulation in Nyquist is easier. But be careful, there may have more than one equivalent mode that can fit you curve. You need to choose the one which makes the most physical sense in your case, which means analyzing the physical structure of your test sample is the primary condition to do this simulation calculation.
in this case, both R2 and R3 can be the charge transfer resistance. It looks you have some coating layer on the electrode? So, in your case, there are two interface reactions? You have to define which R refer to which layer.
Normally, yes. You may have to find out the physical structure for you electrode. A coated anode can have different physical structures as well, like R1+Q2/R2+Q3/R3, R1+Q2/R2+Q3/(R3+Zw), R1+Q2/(R2+Q3/(R3+Zw)), and so on. Sorry, I cannot tell which one suit your case. You need to do several EIS tests to find out which one is the best.
Is there a way of determining which circuit is best suited? I am trying a combination of pseudocapacitive electrode materials and I am not sure which circuit to select in zsimpwin.