In this work, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([bdmim]BF4) ionic liquid is introduced into poly(vinyl pyrrolidone)/poly(vinylidene fluoride-co-hexafluoropropylene) (PVP/PVdF-HFP) blend host to prepare a gel polymer electrolyte (PVP/PVdF-HF-Mg(CF3SO3)(2)) system for a symmetrical solid-state electrical double layer capacitor (EDLC). Ionic liquid-incorporated gel polymer electrolyte (GPE) containing 7.5 wt.% [bdmim]BF4 exhibits the optimum room temperature ionic conductivity of (2.92 +/- 0.02) x 10(-3) S cm(-1) and is electrochemically stable up to +2.4 V. The specific capacitance (Cs) of the optimised GPE at 100th cycle with porous carbon as electrode delivers 95, 133, 108 and 117 F g(-1) at operating voltage of 0.8, 1.0, 1.6 and 2.0 V, respectively, under a constant current density of 100 mA g(-1). The solid-state displays the highest energy and power density of 14 W h kg(-1) and 21 W kg(-1), respectively, at an operating potential of 1.0 V, which qualifies the GPE-IL for symmetrical solid-state EDLC application. (C) 2015 Elsevier Ltd. All rights reserved.