Good prospect of ionic liquid based-poly(vinyl alcohol) polymer electrolytes for supercapacitors with excellent electrical, electrochemical and thermal properties

Poly(vinyl alcohol) (PVA)/ammonium acetate (CH3COONH4)/1-butyl-3-methylimidazolium chloride (BmImCl) based polymer electrolytes were prepared by solution casting method. The ionic conductivity increased with temperature as shown in temperature dependent-ionic conductivity study. The maximum ionic conductivity of (7.31 ± 0.01) mS cm−1 was achieved at 120 °C upon adulteration of 50 wt% of BmImCl. The samples obeyed Vogel-Tamman-Fulcher (VTF) relationship. The glass transition temperature (Tg) of the polymer matrix was reduced by doping it with salt and ionic liquid as shown in differential scanning calorimetry (DSC). Supercapacitor was thus assembled. Wider potential stability range has been observed with addition of ionic liquid. Inclusion of ionic liquid also improved the electrochemical behavior of EDLC. The capacitance of supercapacitor were determined by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge tester. The cell also illustrated energy density of 2.39 Wh kg−1 and power density of 19.79 W kg−1 with Coulombic efficiency above 90%.