Supercapacitor Charging and Discharging

During capacitor and supercapacitor charging and discharging, only the ions move in and out of a thin layer. 

Galvanostatic charge and discharge that are preferably used for the determination of the capacity (capacitance for supercapacitors), the faradic reversibility, the ohmic drop, and the cyclability. 

Conducting polymers belong to a class of materials with exciting potential in the field of supercapacitors because they can be charged and discharged at high rates. 

There are two types of supercapacitors the first one involves the charging and discharging of the electrical double-layer interface, while in the second one, the charge-discharge is accompanied by -> electron transfer, yet with no phase changes, as is the case in batteries. The latter is also referred to as a pseudocapacitor. The -> capacitance of such a supercapacitor is C = Qi + Cg, where Cdi represents the double-layer capacitance and Cg represents the pseudocapacitance. 

Compared with lead-acid batteries, the specific energies of supercapacitors are relatively low ( 10Whkg ). Nevertheless, they can be charged and discharged at very high rates (high-power capability) and can be cycled tens of thousands of times. 

Ban, S., J. J. Zhang, L. Zhang, K. Tsay, D. T. Song, and X. T. Zou. 2013. Charging and discharging electrochemical supercapacitors in the presence of both parallel leakage process and electrochemical decomposition of solvent. Electrochimica Acta 90 542-549. 

---