▎ 摘　　要

The low specific energy of carbon-based electrodes in aqueous electrolytes hampers the commercial application of supercapacitors (SCs). Redox-additive addition with conventional electrolyte is an efficient strategy to enhance the specific energy of SC. Here, we demonstrate the constructive synergistic effect and enhance the electrochemical performance by the addition of [Fe(o-phen)3]2+ with [Fe(CN)6]3-/H2SO4. The increase in the specific capacitance (Cs) of N, P co-doped graphene (NPGO) from 290 F g(-1) in H2SO4 to 685 F g(-1) 1 by the addition of redox-additive [Fe(CN)6]3-with H2SO4. Further enhance in the Cs to 865 F g(-1) has been observing by the addition of second redox-additive [Fe(o-phen)3]2+ with [Fe(CN)6]3-/H2SO4. The specific energy of flexible supercapacitor (FSC) uplift 3.6-times using [Fe(o-phen)3]2+(0.63 mM)+[Fe(CN)6](10 mM)/PVA/H2SO4 electrolyte than 6.8 Wh kg(-1) of PVA/H2SO4. The enhance in Cs and specific energy has been noticing after the addition of [Fe(o-phen)3]2+ with [Fe(CN)6]3-/H2SO4 due to the outer sphere electron transfer reaction between [Fe(o-phen)3]2+ and [Fe(CN)6]3-with H2SO4.