Investigation of different aqueous electrolytes on the electrochemical performance of activated carbon-based supercapacitors

In this study, porous activated carbons (AC) were synthesized by an environmentally friendly technique involving chemical activation and carbonization, with an in-depth experimental study carried out to understand the electrochemical behaviour in different aqueous electrolytes (KOH, LiCl, and Na2SO4). The electrochemical performance of the AC electrode was evaluated by different techniques such as cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy. The results obtained demonstrate that the AC materials in different electrolytes exhibit unique double layer properties. In particular, the AC electrode tested in 6 M KOH showed the best electrochemical performance in terms of specific capacitance and efficiency. A specific capacitance of 129 F g(-1) was obtained at 0.5 A g(-1) with a corresponding solution resistance of 0.66 Omega in an operating voltage window of 0.8 V, with an efficiency of similar to 100% at different current densities.