When I measure the CV of the polypyrrole composite as working electrode using Ag/AgCl, Pt and 2M NaCl as reference electrode, counter electrode and electrolyte solution respectively at scan rates from 1mV/s to 20mV/s it agrees with the theoretical explanation and the expected result that is the gab (broadness) between the forward and reverse curves increases with the scan rates. However, above20 mV/s scan rates the trend starts reverse. The gap between the oxidation and reduction curve stars decrease (narrow) than the lower scan rates. So what can you suggest for this condition? Can I do only scan rates from 1-20 mV/s?
Dear Dagninet - Mekuriaw (who is also at NTUST) asked a similar question. The discussion can be found in the link below. Increasing the concentration of your supporting electrolyte or buffer might allow you to go to higher concentrations.
https://www.researchgate.net/post/is_there_any_condition_at_which_scan_rate_is_inversely_proportional_to_current_during_CV_measurement
When we submit an electrode to multiple cycles many things can happen that may led to different CVs trends as you report. This depends on the sweep rate, potential range, electrolyte concentration, temperature, electrode composition and surface state, etc. Therefore, only a proper analysis of the process may help explaining your observation. Then I am sure you would be able to apply larger sweep rates to study your system.
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