A Novel And Efficient Redox-mediated Electrolyte For Supercapacitor

Electrochemical capacitor, also called supercapacitor,is a new kind of charge storage device between traditional electrostatic capacitor and rechargeable battery, which are expected to exhibit the desirable properties of high power density, fast charging, and long cycling life.Such outstanding properties make them promising energy storage devices, such as in hybrid electric vehicles, mobile electronic devices, large industrial equipment, memory backup systems, and military devices. which can be used for various electrical equipments and hybrid electric vehicles. However, to become primary devices for power supply, the energy density and other performance for SC must be improved further. Recently, there have been a few reports that redox additives were introduced into the electrolyte for carbon EDLCs to substantially enhance the capacitance via redox reactions of the additives between the electrode and electrolyte. In this work, a series of novel redox-mediated aqueous electrolyte is prepared to improving the electrochemical performance of supercapacitors. Adding Na2 S into KOH electrolyte further enhances the pseudocapacitance via both directly contributing pseudocapacitance to Fe3V2O8 electrode and promoting the electron gain and loss of Fe ions,This novel Fe3V2O8-Na2S/KOH system shows an ultrahigh specific capacitance of 282 F g-1 at1 A g-1 in 2 M KOH with 0.03 M Na2 S, more than 100% coulombic efficiency.A novel redox-mediated aqueous electrolyte is prepared by adding sodium persulfate(Na2S2O8) into KOH alkaline electrolyte for the application in most metal oxide based supercapacitors. The specific capacitance was up to 6317.5 F g-1 at 0.5 A g-1 in mixed 2 M KOH and 0.03 M Na2S2O8, more than 100% coulombic efficiency. Fortunately, this new redox-mediated aqueous electrolyte not only suitable for the metal oxide based electrode, but also have much effect to the metal sulfide, vanadate, and phosphate electrode et al. The experiment testified that add redox-active substances in KOH electrolyte was effective and feasible to electrode.