Energy enhancement of quasi-solid-state supercapacitors based on a non-aqueous gel polymer electrolyte via a synergistic effect of dual redox additives diphenylamine and potassium iodide

摘要: Enhancing redox activity at electrode–electrolyte interfaces by dispersing additive(s) in electrolytes is a recent approach to increase the specific energy of carbon supercapacitors. Here, we prepared non-aqueous gel polymer electrolyte (GPE) incorporated with an ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide and dual additives (KI diphenylamine, DPA) entrapped host poly(vinylidenefluoride-co-hexafluoropropylene) for use fabrication A free-standing film GPE shows excellent flexibility, thermal stability (up ∼320 °C), high conductivity (σRT ∼ 4.52 mS cm−1) wide electrochemical window (∼6.2 V versus Ag), indicating its suitability as quasi-solid-state The supercapacitor fabricated using redox-active (containing KI biomass-derived activated electrodes exhibits superior performance over devices GPEs containing pure IL or mixture single additive (DPA KI). synergistic effect leads optimum (∼73.2 W h kg−1) maximum power (∼34.8 kW kg−1), attributable enhanced capacitance (∼337 F g−1) reasonably operating voltage (2.5 V). optimized capacitor good ∼6000 charge–discharge cycles after 20% fade maintains coulombic efficiency 98–100%.