Dear Durai Govindarajan,

You have to use following formula,

Csp= Area under the CV curve/2(scan rate x voltage windowx mass of the material)

from discharge curve,

Csp= Ixt/Vxm

I= current

t=discharge current

V= voltage

m= mass of material

and also please read the papers related to supercapacitor.

Good luck!!!!!!!!!!!!!!! 

Dear Madagonda Vadiyar.

Thank you for your valuable answer, and one more doubt,  Area under the CV curve is giving the Current (I) value  and that value can we directly applying the mentioned formula or not?

how can i calculate the area from that CV curve?

Dear Durai Govindarajan,

Simply, You plot the graph using origin software and choose the analysis option in the origin. After clicking the analysis button you have to choose integration option and automatically you are getting the integrated area of the CV curve.

Dear Astro Karthik, 

At lower scan rates the electrolyte ions have sufficient time to penetrate the pores of the material, while at higher scan rates only it  accumulates on the outer surface. therefore increase in scan rate decreases the specific capacitance. 

Dear........Durai Govindarajan

If you are using EC-biologic instrument.... then...there..is..option to calculate..integrated area of CV..by..copying the whole.single..cycle.CV..with..the help of mouse pointer.....

otherwise..u.can follow...M.Vadiyar...as..He..mentioned...to ..calculate..Intg..area..of..CV..

Now..if.. you .have..intg. area of CV then...u..can..follow..the following..formulae..to calculate the capacitance...

To calculate the capacitance we need to calculate charge....

 charge= integrated area of cv / 2xScan rate

capacitance= charge / potential window

specific capacitance= capacitance / mass of active material

very good, mr.durai r you read some books in electrochemistyok

Hi dear for the specific capacitance some people divide by 2 but some don't divide which one is correct?

Zunair Arslan for symmetric capacitors, i.e. when you use two electrode system which has same capacitance we divide by 2, whereas while using a three electrode system using reference electrode and/or counter electrode we dont divide by 2.

Thank you

Gita Singh Thanks dear

How can we calculate the areal specific capacitance of supercapacitor from CV and GCD ?

If we deposite active material 1cm2 on the Nickle form both sides.

You have to use this formula ,

Cs = Integrated area under the curve/(2*mass of electrode * potential window * scan rate).Using this formula you can calculate specific capacitance from CV.

From GCD you can use this formula,

Cs = current density/(mass of electrode*slope)

To quantitatively evaluate the charge storage capacity, the specific capacitance is determined by the expression Voltammetric charge/(potential window × composite loading). If we considering that the anodic voltammetric charges and cathodic voltammetric charges are not same in that the shape of CV curves is not the idea mirror-symmetry, we use integral area of CV curve/ scan rate represent the sum of anodic and cathodic voltammetric charges. So the specific capacitance is calculated accurately on the basis of the following equation:

C = ∫ i E d E/2( E2 − E1) mν.

1- C. C. Hu, T. W. Tsou, Electrochem. Commun. 2002, 4, 105.

2- B. E. Conway, Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications, Kluwer, New York, 1999, page21.

what is the meaning of 2 in the denominator?

Johnson William J The symmetric supercapacitors where it is a two electrode system their capacitances are the same thus divided by 2.

The specific capacitance, power density and energy density are calculated based on the galvanic charging-discharging curves using the equation as follows:

𝐶 = 𝐼∆𝑡/ 𝑚∆𝑉

𝐸𝑔 = 1 /2 × 𝐶 × ∆𝑉 2

𝑃𝑔 = 𝐸g/∆𝑡

Saleem Mumtaz

can you tell me what will be the formula of charge (Q) in CV???

is it Q = Area of integrated /scan rate

or Q = Area /2*scan rate

If we do not divide the capacitance by 2 in a symmetric system, can the value be reported as the capacitance of the system?

My point is that, should we report capacitance of the whole system or electrode for symmetric capacitors.

Here's a link for calculating area under the curve in Excel. May be helpful for other researchers in future...

https://www.extendoffice.com/documents/excel/5898-excel-calculate-area-under-plotted-curve.html

Madagonda Vadiyar could you please explain to me why you divide the capacitance with 2?

Azega Rajaras Yashwant Pratap Kharwar Gita Singh I am using 3 electrode system While calculating area under the curve for the measurement of capacitance using CV curve with Origin software, which integrated area type we should consider? Mathematical area or Absolute area?. I have considered absolute area divided by 2.

Dear Sumit Dubal

You are on the right way. Always consider the absolute area only.

But I have one suggestion reg. dividing by 2. If you are calculating integral area manually let's say while charging V1 to V2 (Area = V2-V1), and discharging (area = V1-V2) then now the total integral area of CV is = (V2-V1)-(V1-V2) = 2(V2-V1) which is the absolute area of CV. Therefore further dividing by 2 is a mistake.

You just divide the absolute area getting from the Origin by scan rate and potential window to get capacitance and which can be further divided by the mass of active materials to get specific capacitance.

Thank you and Good luck..!!

Yashwant Pratap Kharwar Thank you sir for your brief reply.

Dear Durai Govindarajan, Christina Angelara

Please find the link.....I think it will help you to understand the theory of specific capacitance calculation.....

https://www.youtube.com/watch?v=eNTtH1LEVpY

Thank you and good luck..

We can find the specific capacitance in general C= area of Cv curve/mass of film* scan rate *potential window range