context: The non-aqueous gel polymer electrolyte (GPE) with dual redox additives was prepared by the “solution-cast” technique. Solid pellets of the host polymer PVdF-HFP (1 g) were put in 20 ml acetone and allowed to dissolve properly at room temperature by continuous stirring on a magnetic stirrer for 12 hours. Thereafter, 4 g IL was added in the polymer solution and stirred for another 12 hours. Redox additives (0.04 g KI) and (0.04 g DPA) were added in the PVdF-HFP/IL solution and stirred for further 12 hours at room temperature to obtain a homogeneous and clear solution. The solution was then poured in a glass petri dish and the common solvent acetone was allowed to evaporate slowly at room temperature. Upon complete evaporation of acetone, a free-standing, flexible and mechanically stable GPE film was obtained. The thickness of the dual redox-active GPE film was ∼400 μm. For the comparison, GPEs of compositions PVdF-HFP:IL (20:80 w/w), and PVdF-HFP/IL/DPA and PVdF-HFP/IL/KI with different amounts of redox additives were also prepared by the same procedure, as described above. These GPEs were stored in a dry atmosphere to avoid moisture adsorption. These GPE films were characterized by electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and thermogravimetric analysis (TGA). The room temperature ionic conductivity of all the GPEs was measured by EIS in the frequency range from 105 Hz to 1 Hz. The electrochemical stability window (ESW) for each GPE film was measured by LSV at a scan rate of 5 mV s−1. EIS and LSV were performed on an electrochemical analyzer (CHI660E, CH Instruments, USA). TGA was performed on a Perkin Elmer (USA) TGA-7 system from room temperature to 600 °C at a heating rate of 10 °C min−1 in a N2 atmosphere.
answer: GPE