Can anyone explain me why my CV looks more like this and in some CVs they look more like rectangular? Why so? Whats the reason?
This is a typical distorted CV curve (some papers call it an oval-shaped curve) that is caused by either the sluggish electron transport or slow/insufficient ion diffusion. The reasons of this kind of behavior for case might be:
1) You load too much metal oxide that significantly reduced the overall electrical conductivity of the electrodes;
or 2) You did not make good contact when making electrodes, so the contact resistance adds to the overall resistance.
or 3) your electrode lacks porosity and the ion diffusion throughout the electrode is sluggish.
If the CV curves at much lower scan rate than the current one you show here exhibit rectangular shape, then 3) can be excluded. Consider performing EIS test to check which resistance: the combined series resistance, the charge-transfer resistance or the diffusion resistance dominates the whole system.
Dear Abisheik john Samuel,
This is one of the regular supercapacitors CV curves and it`s correlated with faradic , non faradic process, electrolyte type and electrodes structure/properties as well, please work harder on studying your work fundamentals. Besides, how could be graphite and metal oxide CV voltage range is 0.5 to -0.5 V !!!.
Dear Abisheik john Samuel,
Sometimes, the low electrical conductivity of electrode may lead to the phenomenon of deviating from rectangular shape. And this is normal for some supercapacitor electrode, especially when the electrode is tested at high scan rate. By the way, improving the electrical conductivity is one efficient way to enhance the capacitance property.
This is a typical distorted CV curve (some papers call it an oval-shaped curve) that is caused by either the sluggish electron transport or slow/insufficient ion diffusion. The reasons of this kind of behavior for case might be:
1) You load too much metal oxide that significantly reduced the overall electrical conductivity of the electrodes;
or 2) You did not make good contact when making electrodes, so the contact resistance adds to the overall resistance.
or 3) your electrode lacks porosity and the ion diffusion throughout the electrode is sluggish.
If the CV curves at much lower scan rate than the current one you show here exhibit rectangular shape, then 3) can be excluded. Consider performing EIS test to check which resistance: the combined series resistance, the charge-transfer resistance or the diffusion resistance dominates the whole system.
I agree with Tianyu, as I have worked on graphite/ metal oxide and I also obtained the same typical behavior, I think the possible reason other than Tianyu,
1 your current collector have poor porousity , so poor diffusion
2 at higher scan rate your have this typical oval shape of Cv not rectangular
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