I have made a thin film of PVA with weight of 1gm. I have took the film and done electrochemical analysis with the help of 3 electrode system and Na2So4 as electrolyte at 10mV/s scan rate. as per my calculation I got value of 7.9 mF/g specific capacitance.
I would like to know whether I have calculated the right value or not because in reported work they have calculated up to 25 F/g of specific capacitance of blank PVA film.
kindly please help.
Hi Bhargav Raval,
I used your attached data and I got 3.7 F/g.
For your information, the generic equation for capacitance from CV is
C=S/(2*mass*scan rate*potential window)
Here S is the integral area of the CV curve with y-axis in A and x-axis in V (exactly the one you show). mass is the electrode mass, which equals 0.001 g in this case. Scan rate is 0.01 V/s and the potential window is 1.2 V.
Make sure you use SI units and avoid overlooking the 2 in the denominator.
Dear all,
The specific capacitance (C) in F/g is calculated from the applied CV measurement according to: C = S/(m.u.DV)
where S is the integrated area of the CV diagram (A.V), m is the mass of the active material (g), u is the scan rate (V/s) and DV is the potential window (V) which is here equal to 1.1 V. Good luck.
You must be careful towards the units of input parameters in the equation mentioned by Dr Fakiha Heakal, i.e. I ( in A not mA), V (V), m (g), u (v/s) and dV (V). This a very important notation to get a correct calculation.
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