New supercapacitors based on the synergetic redox effect between electrode and electrolyte

Abstract

Redox electrolytes can provide significant enhancement of capacitance for supercapacitors.However, more important promotion comes from the synergetic effect and matching betweenthe electrode and electrolyte. Herein, we report a novel electrochemical system consisted ofa polyanilline/carbon nanotube composite redox electrode and a hydroquinone (HQ) redoxelectrolyte, which exhibits a specific capacitance of 7926 F/g in a three-electrode system whenthe concentration of HQ in H2SO4 aqueous electrolyte is 2 mol/L, and the maximum energydensity of 114 Wh/kg in two-electrode symmetric configuration. Moreover, the specific capacitanceretention of 96% after 1000 galvanostatic charge/discharge cycles proves an excellent cyclic stability.These ultrahigh performances of the supercapacitor are attributed to the synergistic effect both inredox polyanilline-based electrolyte and the redox hydroquinone electrode.