Generally, voltammograms of intercalation materials show peak(s) at potentials corresponding to the intercalation phenomenon. If there are multiple peaks, pseudo-valleys are formed between them. I would like to know if the same potentials are assessed by EIS, is there any general rule/rationale supporting whether increase or decrease of the Warburg coefficient / diffusion time constant (NOT the diffusion coefficient) at such potentials, and possibly, why?
At a glance, I see no direct inter-correlation between peaks in CV, corresponding to redox reactions, and parameters of the Warburg element, corresponding to the diffusion process. I do remember there are reports that reveal a correlation between the diffusion coefficient and phase stages of graphite anode for lithium-ion batteries. Regarding the Warburg impedance, I recommend my recent work: Article Diffusion impedance of electroactive materials, electrolytic...
Maybe it[1] is helpful for a quite good correlation between (near) peaks in CV and the chemical diffusion coefficient.
1. Self-Activating, Capacitive Anion Intercalation Enables High-Power Graphite Cathodes
Article Self-Activating, Capacitive Anion Intercalation Enables High...
Warberg element indicates the charge transport in dielectric. The increase or decrease in warbergs coefficient changes charge transport.
Please refer the following article reference:
https://doi.org/10.1088/2053-1591/aad406
Thanks
Dear Ioannis Samaras
Thank you so much for your comment and paper suggestion.
Dear Anamika,
Thanks for your comment and the paper suggested. I had a quick look at that paper and it appears the Warburg element has been manily
analysed and discussed in the context of supercapacitors, where the diffusion of ions is mainly in the pores of the active material without need to atomic level insersion /deinsersion. Therefore, information provided there would be of the scope my current question, wherein a possible relation between Warburg coefficient and ease or difficulty of intercalation process is sought.
Nevethelss, thanks for your contribution.
Dear Jun Huang ,
Thank you so much for your answer. the papers that you mentioned was very useful. However, I like to see these variation of Warburg in a redox metal oxide such as MnO2 rather than carbon system which does not show pseudocapacitive properties.
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