Commonly, yes[1,2].

1. Is it necessary to perform DC polarization technique for estimation of ion transport ?

2. EIS wIth DC polarization(s).

thanks a lot, Sir

I have the same question. I found that we need to perform Hebb-Wagner or Wagner DC polarization using ion-blocking electrode to calculate the ionic and electronic contribution. The question that I am trying to answer is what is the difference between these two methods: In a d.c. Wagner, we sandwiched the sample between two ion-blocking electrodes (e.g stainless steel) and polarize the cell using constant potential and measure the initial and steady-state current. However, in the Hebb-Wagner method, we have to sandwich the sample between one ion-blocking electrode and one reversible electrode (the electrode that can transfer both ions and electrons) and then we need to polarize the cell. But I don't understand why we need to have one reversible electrode and which method is more precise. Depending on the ions that we have in the sample, sometimes it is hard to find a reversible electrode. For example, if we want to measure the Li+ and electron contribution, the SS can act as a ion blocking electrode and Li metal can act as the reversible electrode. However, in my system I am trying to measure the contribution of protons (H+) and electrons, so it is very hard to find a reversible electrode can allow both protons and electron to be transported.

Dear Amir Chamaani,

what is your powder sample (pellet, system[1]) for EIS measurements ?

1. Quotation [from Amir Chamaani]: However, in my system I am trying to measure the contribution of protons (H+) and electrons, so it is very hard to find a reversible electrode can allow both protons and electron to be transported.

Dear Ioannis Samaras,

The pellets are made of some proprietary ceramic materials but mostly transition metal oxides. I would like to measure the electronic and protonic transference number using the D.C. polarization technique.

Best,

Dear Amir Chamaani,

try some impedance measurements with your solid electrolyte pellets, having a low thickness, in a Swagelok cell[1].

Use Indium-foils and make a set of EIS-spectra with Vdc polarization, at least, in the list: -50mV, -20mV, 0mV, 20mV, 50mV, 100mV, 150mV, 200mV.

Note the idc, also, for a comparison of a near to DC (R-values), with Z-values(Fmin[2]).

Measure EIS-spectra, "fast"[2], within some hours.

Measure a 2nd "same set" of non-fast EIS-spectra, e.g. now, waiting, at least, 15min, between spectra, after the Vdc polarization(s).

Try to keep the (same, low) AC excitation voltage (