Fascinating the Supercapacitive Performance of Activated Carbon Electrodes with Enhanced Energy Density in Multifarious Electrolytes
Supercapacitors are rapidly growing in the market due to their high-power capability but their energy is low while comparing with batteries. However, their poor energy density is modulated with redox additive electrode materials either by decoration or composite fabrication. In addition, the energy density of the supercapacitors could be increased using the redox reaction in electrolyte itself. Herein, a high energy supercapacitor is demonstrated using activated high surface area carbon derived from cauliflower and redox additive electrolyte. The activated carbon shows mesopores with a specific surface area of ~1500 m2/g and a maximum specific capacitance of 310 F/g is grasped in two electrodes symmetric configuration using 1M H2SO4 electrolyte. Whereas, the fabricated device shows a high specific capacitance of 78 F/g and 92 F/g in non-aqueous organic and ionic liquid electrolyte with an energy density of 17 Wh/kg and 29 Wh/kg, respectively. The energy density of the supercapacitor device is further enhanced using the novel redox additive 0.01 M KI in Na2SO4 electrolyte. It shows a specific capacitance of 520 F/g and a maximum energy density of 58.5 Wh/kg, which is very high and comparable to lithium-ion batteries.