Hello,i want to study the kinetic behavior and the average diffusion coefficients of my anode material from CV measurements using Randles−Sevcik equation.
How to calculate the Li/Na ion concentration C (mol cm−3) in the lattice of the material of study for different cathodic and anodic peaks at the different CV scan rates.
I appreciate your help.
Thanks in advance.
to find the concentration using RS equation you need to draw a calibration plot from known conentrations
Difficult question to answer. In the field of lithium ion batteries, I have seen researchers using different values including the concentration of electrolyte solution (1M LiPF6) in Randles−Sevcik equation (To me it does not make sense). As this concentration corresponds to lithium concentration on or inside electrode material, therefore, i try to consider the chemical phases of anode material to find the value of concentration.
Imagine you have Sn electrode and during lithiation you reach a phase (Li1Sn1) at a certain potential (Search the literature for different phases at different potentials). At this point, find the density of Sn which is 7.31 g/cm3 and corresponds to 0.0615 mole/cm3. If we consider the above mentioned phase, lithium and tin are equi-molar, so the concentration of alloyed Lithium at this phase inside Sn electrode is 0.0615 mole/cm3. (I am also not sure about my calculations if anyone else find a better answer please correct me)
Thanks Zahid and Umair for your reply.
I know that i have to draw cv plots at different scan rates,but for calculating the average diffusion co-efficient from the slope(Ip (A) peak current ~ v (V s−1) scan rate) using RS equation i need ions concentration.
So,my question is about how to calcualate the Li/Na ion molar concentration of alloying and dealloying phases at different cathodic and anodic peaks at different cv scan rates (as an example given by Umair of alloying and dealloying of Lithium in case of Sn upon charge and discharge) like whether to take from literature like Na9Sn4, Na3Sn, and Na15Sn4 (Sn electrode for Na) as described or is there any method to do that.
I need your suggestions on this regard.
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