Dear Jamil A. Buledi ;

Supercapacitors are increasingly used for energy conversion and storage systems in sustainable nanotechnologies. Graphite is used as a conventional electrode utilized in Li-ion-based batteries. more details in the references;

• Article Advanced materials and technologies for supercapacitors used...

• Article Cyclic voltammetry behavior modeling of fabricated nanostruc...

Thank you so much Dr. Mahmood H.

Dear Jamil A. Buledi

Cyclic Voltammetry (CV):

Cyclic voltammetry is an electrochemical technique that takes place at electrode electrolyte interface for qualitative information of electrochemical reaction. Cyclic voltammetry is used to understand the mechanism of redox reaction and electron transfer kinetics of an electroactive specie in electrolyte. The CV excitation signals are in triangular waveform on scanning the potential of a stationary electrode linearly (figure 3.17).

Figure 3.17 Excitation signal for cyclic voltammetry

Here as in figure 3.17 the voltage is swept between the two potential values V1 and V2. In the forward scan the voltage starts from the lower potential (V1) at the end ‘a’ and reaches the higher potential (V2) at the end ‘b’ during which oxidation reaction occurs. Reduction reaction occurs during the reverse scan i.e. when the potential moves from higher value V2 to the lower value V1 (from point (b) to (c)). The reduction potential can be determined for a material deposited on the electrode. These end potentials are known as switching potentials as these potentials are enough to cause oxidation or reduction of an analyte.

Figure 3.18: A CV recorded for a reversible single electrode transfer reaction

CV is an electrochemical technique for measuring the current response that develops in the electrochemical cell during a linearly cycled potential sweep between the chosen potential window. This process is repeated multiple times during the scan and changes in the current value are measured by the device. This scan generates a duck-shaped plot that is called cyclic voltammogram as shown in figure 3.18. In Figure 3.18, the oxidation process occurs from the initial potential at end point “a” to the switching potential at the end point “d”. In this region the potential is scanned positively to cause an oxidation reaction. The resulting current is called anodic current (ipa). The corresponding peak potential occurs at “c”, and is called the anodic peak potential (Epa). After the switching potential at “d” has been reached, the potential scan starts negatively from end point “d” to the end point “g”. Reduction reaction occurs during this half cycle and results in cathodic current (Ipc). The peak potential at the point “f” is called the cathodic peak potential (Epc). The Epaand Epc is reached when all of the substrate at the surface of the electrode has been oxidized and reduced, respectively

Thank you so much Yogesh kumar for your valuable answer