The calculated specific capacitance value from GCD analysis is comparatively low with CV analysis. why? can any one explain?
The calculated specific capacitance value from GCD analysis should be near the values from CV analysis. You should make calculation at the same scan rate for (CV) and (GCD).
As Mohamed Elsayed Harb. However, the calculated (apparent) specific capacitance (Cas) value might scale[1], also, with 1/Vrate (Vrate=dV/dt) in (the same approach) your CV[2] technique. So, your actual contrast might be (not among the techniques, but) among rates of the processes, e.g. the identification of the charges and the charges' storing processes.
1. In your (specific) case study.
2. For the same Potential window(s) in your CV(s).
Dear Manickam,
All the calculations from cyclic voltammetry (CV), charge-dischareg (CD), electrochemical impedance spectroscopy (EIS) have their typical point of dependence factors. But among them, maximum researchers have recommended CD to be the technique of choice for various reasons.
I think there is no point to coincide the capacitance values from CV, CD or EIS. The values are stongly depending upon scan rate (for CV), current density (for CD), low frequency range (for EIS). Try to report the highest capacitance values at higher scan rates (5 or 10 mV/s for CV) and high current densities (1 or 2 mA/cm2 for CD) as supercapacitor is related fast and quick charge storage.
Go through my publications attached below. It can help you.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.604.7608&rep=rep1&type=pdf
Article Electrochemical approach of chemically synthesized HgS nanop...
Article Chemically deposited Bi 2 S 3 :PbS solid solution thin film ...
Article Large scale flexible solid state symmetric supercapacitor th...
Why is only discharge time and not the charging time is taken for calculation of capacitance from CD curves?
Disha Soni because we need how much useful power we can take from the supercapacitor device. During the charging process , some of the power you supply power to the device to charge the device is consumed in the equivalent series resistance. So, not all the energy supplied during charging can be taken again from the device during discharging.
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