Investigation on Self-Discharge Mechanism of Neutral Aqueous Electrolyte Based Electric Double Layer Supercapacitor

Supercapacitors are capable of holding electrical charges that are much larger than conventional dielectric capacitors. A supercapacitor was constructed using active carbon electrodes, deposited on metal current collectors and they were separated by a non-conducting membranes soaked in an electrolyte. An electrical double layer is developed at the interface between active carbon and the electrolyte. The electrical properties of constructed capacitors were investigated to identify the drawbacks of these systems. Self-discharge has been an inescapable issue of electrical double layer type super capacitors and it reduces cell voltage of the capacitor. The data collected from fabricated supercapacitor was used to model the self-discharge behaviour with the aim of understanding the discharge mechanism of these capacitors. It was found that in addition to ohmic leakage mechanism, there is another dominant mechanism.