Performance of A Sodium Thiocyanate Based Gel Polymer Electrolyte In Redox Capacitors

Solid state redox capacitors have received a tremendous interest in terms of several characteristics such as their fast energy delivery, short charging time, high power density and extended durability. Due to the absence of a liquid electrolyte, they are free from drawbacks of leakage and unsafe. In this study, preparation and characterization of a redox capacitor consisting with two identical polypyrrole (PPy): dodecylbenzenesulfonate (DBS) electrodes and a gel polymer electrolyte (GPE) based on polyvinylidene fluoride (PVdF), ethylene carbonate (EC), propylene carbonate (PC) and sodium thiocyanate (NaSCN) is reported. The GPE having the composition, 0.4 PVdF: 1 EC: 1 PC: 0.075 NaSCN (by weight) showed the maximum conductivity of 2.25× 10^-3 S cm^-1. Redox capacitors were characterized using Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Galvanostatic Charge Discharge test. They exhibited an energy density about 0.25 W h kg^-1 and an average power density of 4 kW kg^-1.