I have Cu2O/CuO coated on Cu mesh and would like to characterize its electrochemical properties using CV and Impedance analysis. I have tried using 0.5M and 1M of Na2SO4 (scan rate 10mV and 20mV), but certain samples are unstable during the test (see attached figure). However, they all work well in 1M KOH. My concerns are:
1) Anybody has the slightest idea on why it didn't work under my conditions?
2) May I proceed with the characterization using 1M KOH or is 6M KOH (like many of the researchers did) is a better idea?
Thank you in advance.
Hi there,
I saw the current - potential curve its unstable at range -0.2 to -0.7. So, I suggest for you following advices:-
- Check the resistance of reference electrode must be have low impedance.
- Check the connection alright without any losses.
- Check the sense of reference electrode ,especially with EIS measurements.
- Select a wide range of scan rate with lower interval value.
- I expect the concentration of 1M is highest at this situation if lower it to 0.5 M.
- Check the bubbling of gas and pass the nitrogen gas for 2h and run the exp.
- Pluz, check the following files to introduce the enough help.
Regards,
Try by adding some NaOH and KOH when using Na2SO4(aq) as electrolyte, maybe pH is influencing on films stability (it is for expectancy that they are more stable in alkaline medium). Also recheck your electrical contacts in the electrochemical system when doing the measurements.
Best regards
Hello Min Hui Yap,
Your CV is not the perfect and stable as well. And the current response is very low. This because of unsuitability of electrolyte. You should vary the electrolyte and concentration to get maximum specific specific capacitance, stability for supercapacitor electrode. Potential window also should be optimized for each electrolyte. A fixed potential window is concerned according to the selected electrolyte. It maybe (+) ve or (-) ve or both (for three electrode system including reference electrode). It'll be only (+) ve for device (two electrode system as counter and reference electrode act as one terminal). Test in only one electrolyte is not a good idea.
Thats not the matter whatever the others do. In other research articles, authors synthesize electrode material with different techniques. So, the morphology, surface area, porosity of the materials are different for each though the active material is same. So, favorable electrolyte for the same material synthesized by others can be different, concentration too. You should go for all the electrolyte variation, and pick the best one. then concentration as I've done in my publications. that's the standard method.
Check my each publications. I have calculated and described briefly. I think it will clear your concept. I have attached a few here.
Article V2O5 encapsulated MWCNTs in 2D surface architecture: Complet...
Article Chemically deposited Bi 2 S 3 :PbS solid solution thin film ...
Article Free-standing flexible MWCNTs bucky paper: Extremely stable ...
Article Electroless-deposited Ag nanoparticles for highly stable ene...
The selection of electrolyte material may very with the same material due to fabricating using different methods. So you can not choose that electrolyte which is chosen by others for the same material. Because there may be the difference in surface morphology, porosity and active surface area. Therefore, for getting the favorable electrolyte and optimizes concentration you should try at least three different electrolyte for your sample and I hope you will find the best results. In addition, you should check all the electrical connections of your system during the CV analysis.
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