Table 3.

Technical merits and demerits of the CV, GCD, and EIS techniques.^{[ 60} , ^{61 ]}

Techniques	CV	GCD	EIS
Principle	CV is varying the potential against time and measuring the current	GCD is applying a positive or negative current against time and measuring the voltage	Measuring impedance of a power cell as a function of frequency by applying alternating current (AC)
Merits	Degradation process Specific capacitance Differentiate between EDLC and PC	Capacitance calculation Differentiate between EDL and PC	Resistance calculation Specific capacitance calculation Differentiate between resistive and inductive nature Nondestructive technique Relaxation time for recharging Exhibit Degradation behavior
Demerits	Show only kinetic aspects; thermodynamic aspect is neglected	Exhibit same triangular shape for all double‐layer capacitive materials	Evaluation at small voltage only Discrete behavior above 106 Hz