Simultaneous effect of fluorine impregnation on highly mesoporous activated carbon used in high-performance electrical double layer capacitors

Owing to the increase in need for high-performance energy storage devices, activated carbon has attracted considerable attention as an electrode material for electrical double-layer capacitors (EDLCs). However, the conventional manufacturing process of activated carbon is seriously limited by the depletion of raw material sources. Biomass-based activated carbon, which is currently considered as a breakthrough, exhibits performance limitations such as low specific capacitance and poor high-rate performance. In this study, we propose the use of fluorine-doped mesoporous carbon (F-MAC), which is derived from Ecklonia cava using fluorine impregnation and KOH activation, to address the above challenges. F-MAC exhibits high specific capacitance (184 F/g), excellent high-rate performance (155 F/g at a current density of 20 A/g), and superior cycle stability (82.8% capacitance retention after 2,000 cycles). These performance improvements are attributed to the increased surface area, high mesopore volume fraction, fluorine-doping effect, and high concentration of oxygen functional groups.