Effect of aqueous electrolytes on the electrochemical behaviors of supercapacitors based on hierarchically porous carbons

► Comparable electrochemical performances in various aqueous electrolytes. ► In 6.0 M KOH the supercapacitor performs the best electrochemical behaviors. ► The highest energy density of the supercapacitor in 6.0 M KOH is 11.54 Wh kg−1. ► In 6.0 M KOH the supercapacitor has the shortest relaxation time of 0.62 s.