Dear all,
I have tried to calculate the diffusion coefficient using the warburg impedance data. I have tried to use the formula as in the attachment. I am not sure how to calculate the concentration of lithium without using CV measurement. Is this the lithium capacity until the potential at which impedance measured?
I am using three different binders for the same material. Can I keep the number of electron transferred as constant for the material at a particular potential to get the trend?
Thanks in advance.
Dear Raam,
It is important to achieve the EIS with professional skills and know the principles and advance information about it as well how you fit and select a suitable the circuit for the simulation the BODE plot. Moreover, I attached the steps to determine the diffusion coefficient " I can't write it on this page so I designed the answer as PNG file ex. "
Regards,
Dear Raam,
It is important to achieve the EIS with professional skills and know the principles and advance information about it as well how you fit and select a suitable the circuit for the simulation the BODE plot. Moreover, I attached the steps to determine the diffusion coefficient " I can't write it on this page so I designed the answer as PNG file ex. "
Regards,
Dear Dr. Yousif,
Thanks for the answer. I have already calculated the warburg coefficient(sigma) from the slope. All I need to know is the concentration of Li. In my case, I am making impedance measurement in the delithiation at 0.2V (potential range 5mv to 0.9V vs. Li). My electrode has two different component including graphite. Since I am taking the impedance at 0.2V, I assumed the contribution at that potential is fully from graphite so I assumed the number of electron transferred as 1.I want to know whether it is a correct approach.
In addition to that, using differential capacity curve calculated the remaining reversible capacity (between 0.2V and 0.9v) for the lithium concentration. Do these assemptions make any sense?
Regards,
Raam
Hi Dr. Qhatan Adnan Yousif
can you please share the reference for your attachments.
Thanks
Mangesh
Hi everyone,
Greetings to all.
I am bit confused in calculating the value of C in diffusion equations. How to determine the C?
C is bulk concentration of lithium in active material or concentration in 1.3M LiPF6 in ethyl-carbonate/diethyl-carbonate/ethyl-methyl-carbonate (30:40:30).
Please share your opinion.
Best
Aditya
The ion diffusion coefficient is an important kinetic parameter, and it could be calculated from EIS by the following formula (see attached file).
Also, you can check these research papers;
1- Nano Lett. 2016 Mar 9;16(3):1523-9. DOI: 10.1021/acs.nanolett.5b03576. Epub 2016 Feb 19.
2- P.-P. Wang et al. / Electrochimica Acta 169 (2015) 440–446. Article Low temperature electrochemical performance of β-Li V2O5 cat...
Thanks a lot Mohammad R. Thalji Sir
but how about C; is the concentration of electrolyte or something else.
Say in my case I use 1.3 M LiPF6.
Please share your view points
in this case I choose C = 1.3, is it right?
Dear Aditya N. Singh
C is the molar concentration of electrolyte (mol cm-3).
So, in your case C=0.0013 mol cm-3.
R = 8.314 J mol-1 K-1, T is the absolute temperature (K), A is electrode area (cm2), and F is Faraday constant (96500 C mol-1).
I am not reaching to the unit of dissuion constant. ie.e cm2S-1. Can canybody help me.
Dear Mohammad R. Thalji
Greetings.
Hope things are good at your side.
I need one favor, I am stuck in diffusion calculations. Could you please assist me?
Best
Aditya
Thank you so much Mohammad R. Thalji
I have messaged you my doubts. Please have a look at it.
Best
Aditya
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