Thanks a lot. Only Nicholson's method is applied to calculate the rate constant in my work. Your suggestion is very good. I am further verifying these results. I agree with you. This parameter has an important  relationship with work electrode material. Here, I have always wondered about it: if this value obtained at the liquid electrode  is smaller than that on the inert electrode ,may I think that the electrochemical reaction of this system is slower than that on inert electrode? if Actually, in my opinion, the activity of liquid electrode is stronger than the inert electrode, this reaction should be faster. So, the rate constants should be larger than that obtained on inert electrode. How about your opinion? Thanks.

Thanks for your feedback.  I know this resistance and this value at the liquid Zn electrode is larger than that on the inert electrode. Actually, this value had been corrected duriing the calculation. But I don't quite get you—"This interface may posess different behavior".Could you tell me more detail about it. Still thank you.

I have studied electrochemistry for over 30 years, including molten salts, but I have never heard this phrase "scan rate constant". Would you please explain what it is?

Hello, Pro. Chen, Thank you for your question.  This parameter I mentioned was standard Rate constant. It is a kinetic parameter and is  the measure of the kinetic facility of a redox couple. Then  I read some of previous literatures and the section  about this parameter in Bard book. I think  carefully about this. It should be rate constant. You are right. Thanks.

@ Lixia Luo, thank you for your explanation, and I think you can modify your question (edit) so that others will not be confused.