Thank you Mr.Artur Braun

Mobility, Hall effect and pressure dependent conductivity tests may help in differentiating ionic and electronic transport - none of them is easy :)

Dear Kavitha,

Ionically blocking electrodes is a possibility. I have used dense gold on PZT (lead zirconate titanate) also a perovskite. I was able to separate ionic from electronic conduction. But there is no guarantee that it will work always. Another option is to use electronically blocking electrodes (thin layer of e.g. YSZ on both sides (PLD). That will block the electronic component. Third option is to measure the oxygen diffusion coefficient using Conductivity Relaxation, but this is also not a simple route.

Success with your experiments,

Bernard A. Boukamp

Thank you for your idea Mr.Bernard A. Boukamp. I will try the methods you suggested...

Is the conductivity calculated from ohmic resistance can be called as ionic conductivity?

Dear Kavita,

 No! It all depends on a number of factors. What type of electrodes are used? This is very important, e.g. Pt and Ag are very active as oxygen electrodes, leading to a relatively low electrode resistance (polarization resistance). Au is quite inactive and can most of te times be regarded as a ionically blocking electrode. Futrhermore, if there is also appreciable electronic resistance then the situation is more complex. To get an impression of how you can deal with mixed electronic and ionic conductivity see my paper in Solid State Ionics 170 (2004) 239. Let me know if you do not have access to this paper (at: [email protected]).

Best regards,

Bernard A. Boukamp

Ohmic resistance is the total effect caused by both ions and electrons. 

As Prof. Bernard and Artur Braun suggested, ion blocking electrodes could be used to separate the ionic and electronic conduction because these electrodes will behave as ideal capacitors (pure capacitance effect, ie., ionic). No mixed conduction is possible when we used these types of electrodes (ex: SS, Au electrodes)  

or you can measure the total conductivity as a function of O2 partial pressure at different temperature unless no partial oxidation takes place because it leads to small amount of electronic conduction in the system. This approach can be suitable if you are working with pure oxide conductor ( (ex YSZ) under O2 atm then one might assume that all the conductivity is ionic.

Good luck.

Ya very true...Unless experiments carried out in O2 partial pressure at different temperatures or using Au blocking electrodes, we cannot claim as ionic conductivity,it is total conductivity with both electronic and ionic contribution...

Thanks Prof.Bernard and Ajith kumar.

Hi Kavitha,

Very good suggestions by everyone here. What has been suggested is the right way to characterize charged-species transport. However, these methods can be difficult. One thing you can do for a relatively simple experiment is measure transport by gas analysis. Make a dense sample of your material, put porous electrodes on both sides, and place the sample between two gas chambers. In one chamber, have a high pO2, and in the other a low pO2. You can allow a current (or apply one even) to drive O2 from one side to the other, measure the change in oxygen in the chamber by gas analysis, and compare that to the Faradaic current. The nice thing about this measurement is you get EMF data from open circuit, and additional transport data from current vs. oxygen flux data.

It probably isn't as accurate as the other suggestions, but depending on what you have available (PVD vs. MS/GC), you might be able to get the data you need.

Ajith Kumar , Kavitha Karuppiah can you share some reference as in how exactly we could separate the ionic and electronic contributions of conductivity measuring in the presence of Oxygen partial pressures at different temperature. I've recently read Wagner's method to perform dc polarization expt. to get the transference number of both ionic and electronic. Is that more efficient than this?