High performance solid-state supercapacitor with PVA–KOH–K3[Fe(CN)6] gel polymer as electrolyte and separator

A gel polymer PVA–KOH–K3[Fe(CN)6] is prepared by potassium hydroxide and potassium ferricyanide doped polyvinyl alcohol, and a solid-state supercapacitor is assembled using the gel polymer as electrolyte and separator, activated carbons as electrode. The gel polymer exhibits flexible, high ionic conductivity and wide potential properties. The electrochemical properties of the supercapacitor are investigated using cyclic voltammetry, galvanostatic charge/discharge, and impedance spectroscopy techniques. The electrode specific capacitance of the supercapacitor can be as high as 430.95 F g−1, and after 1000 cycles at a current density of 1 A g−1 it still remains higher than 380 F g−1. The energy density and power density of the supercapacitor reach 57.94 Wh kg−1 and 59.84 kW kg−1, respectively. These novel flexible gel polymers are desirable for applications in supercapacitor devices.