Development and optimization of ionic liquid based gel polymer electrolyte for all solid-state supercapacitor

Supercapacitors are promising candidates due to its high power density, long-life cycle and stability. However, supercapacitors which use liquid electrolyte face several problems such as safety and low specific energy. In this study, we optimized the electrochemical behavior of all-solid-state supercapacitor when we use various types of ionic liquids based gel polymer electrolyte. The electrochemical performances of the symmetric supercapacitor are evaluated by using cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), and galvanostatic charge/discharge tests(GCD). The highest specific capacitance is 160.6 F g−1 at scan rate of 5 mV s−1 with PVA/KI/EC/EMIBF4 based quasi-solid-state electrolyte and the supercapacitor exhibited high energy density of 180.67 Wh kg−1 at a power density of 375 W kg−1.