Quasi‐Solid‐State Supercapacitor Using Redox Additive

In this paper, comparative performances of the supercapacitor based on different redox additives (vanadyl sulfate [VOSO 4 ] and potassium iodide [KI]) incorporated gel polymer electrolytes (redox additive gel polymer electrolytes [RGPEs]) are reported. RGPEs were prepared by entrapping liquid electrolyte solution NaClO 4 /ethylene carbonate (EC):propylene carbonate (PC) in host polymer PVdF‐HFP along with redox additives via conventional solution casting techniques. It is observed that the ionic conductivity of pristine gel polymer electrolyte (GPE) is dependent on the content of redox additives (VOSO 4 and KI) and temperatures. It is improved by adding redox additive 0.1 wt% VOSO 4 (RGPE‐1) and 0.3 wt% KI (RGPE‐2) with corresponding ionic conductivity values to ∼3.25 × 10 −3 and ∼4.02 × 10 −3 S cm −1 , respectively. Further, two quasi‐solid‐state supercapacitor cells are fabricated using the optimized GPEs RGPE‐1 and RGPE‐2 with honeycomb‐based activated carbon (HCAC) electrodes. The comparative performances of the supercapacitor cells are evaluated and analyzed in terms of different electrochemical characterization techniques such as impedance, electrochemical stability window (ESW), cyclic voltammetry (CV), linear sweep voltammetry (LSV), and galvanostatic charge discharge (GCD) characteristics.