Investigation of different aqueous electrolytes on the electrochemical performance of activated carbon-based supercapacitors
Department of Physics, Institute of Applied Materials, SARCHI Chair in Carbon Technology and Materials, University of Pretoria, Pretoria, South Africa; Department of Chemistry, University of Pretoria, Pretoria, South Africa
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. © The Royal Society of Chemistry 2015.
Activated carbon; Capacitance; Carbon; Carbonization; Chemical activation; Cyclic voltammetry; Efficiency; Electrochemical impedance spectroscopy; Electrodes; Electrolytes; Electrolytic capacitors; Aqueous electrolyte; Corresponding solutions; Electrochemical behaviour; Electrochemical performance; Galvanostatic charge/discharge; Impedance spectroscopy; Operating voltage; Specific capacitance; Electrochemical electrodes
97994, National Research Foundation; UP, National Research Foundation