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

Abstract

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 Ω in an operating voltage window of 0.8 V, with an efficiency of ∼100% at different current densities.