Synergistic interaction between redox-active electrolytes and functionalized carbon in increasing the performance of electric double-layer capacitors

Abstract

The increasing demand of high-performance supercapacitors has aroused great interest in developing specific capacitance and energy density. Active carbon (AC) has attracted much attention as a promising electrode material for electric double-layer capacitors (EDLCs). Here, a facile strategy has been employed to fabricate high-performance EDLCs using the surface-oxygen functionalized active carbon (FAC) as an electrode and 2 M KOH with K3Fe(CN)6 as an electrolyte. In this system, K3Fe(CN)6 was used as a redox additive to enhance the performance of EDLCs. A 38.5% increase in specific capacitance (207.7 F g−1) was achieved compared with the KOH electrolyte without adding K3Fe(CN)6 (152.9 F g−1), due to the synergistic effects between oxygenic functional groups and redox electrolyte. These findings provide an alternative route to improve the performance of EDLCs, which are promising candidates for the broad applications of high-performance supercapacitors.