Investigations on capacitive properties of the AC/V2O5 hybrid supercapacitor in various aqueous electrolytes

Abstract Amorphous V 2 O 5 sample was prepared by a melt quenching method. The hybrid supercapacitor was fabricated with V 2 O 5 positive electrode and activated carbon (AC) negative electrode in various aqueous electrolytes. Its electrochemical properties were determined by cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy. The results showed that species of aqueous electrolyte, current density, potential range and the active mass ratio of AC to V 2 O 5 had great effect on the capacitive properties. In the potential range of (−0.3 to 0.7) V, the hybrid capacitor delivered the specific capacitance of 32.5 F g −1 at a current density of 200 mA g −1 in 2 mol L −1 NaNO 3 solution when the mass ratio of AC to V 2 O 5 was 1:1, and simultaneously exhibited excellent capacity retention. The specific capacitance only slightly decreased with the increasing current density. When the mass ratio of AC to V 2 O 5 was increased to 3:1, the capacitance of the AC/V 2 O 5 hybrid capacitor was similar to that of the V 2 O 5 /V 2 O 5 symmetric cell.