Synthesis and performance assessment of silica dispersed nano-composite polymer gel electrolyte for high-performance solid-state supercapacitors.

• Synthesized and optimized NCPGE [(1:4){PVDF-HFP + EC-PC-TEABF 4 } + SiO 2 (15 wt%)] showed highest conductivity of 8.2 × 10−3 Scm−1. • Ionic transference number ∼ 0.96 and relatively larger electrical potential window ∼ 3.5 V proved synthesized NCPGE as potential candidate for application in supercapacitors. • Electrochemical performance evaluation of fabricated supercapacitor by impedance spectroscopy, cyclic voltammetry and galvanostatic charge discharge techniques. • High conductivity, large potential window, stable performance at higher scan rates confirm that the dispersion of SiO 2 nanoparticles in PGE has significantly improved the quality of synthesized electrolyte. Nano-composite polymer gel electrolyte (NCPGE) films are prepared by incorporating liquid electrolyte (EC-PC-TEABF 4) into polyvinyldinefloroide co-hexafluoropropylene (PVDF-HFP) polymer with dispersed SiO2 nano-particles using solution cast technique. The NCPGE is optimized for the highest ionic conductivity by varying wt% of SiO2 nanoparticles in PGE [(1:4){PVDF-HFP + EC-PC-TEABF 4 }]. Highest conductivity of 8.2 × 10−3 Scm−1 is found for optimized composition [(1:4){PVDF-HFP + EC-PC-TEABF 4 } + SiO 2 (15 wt%)] of NCPGE. Structural and morphological studies have been done using XRD, FTIR, and SEM. Frequency dependent dielectric behaviour is understood using dielectric constant and modulus analysis in a wide range of frequencies. The ionic transference number is 0.96 and an electrochemical potential window of ∼ 3.5 V has been obtained. Fabrication of electric double layer capacitor (EDLC) is done by sandwiching NCPGE between activated carbon (AC) electrodes. The electrochemical performance of fabricated supercapacitor is evaluated by impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge techniques. Results show significant improvement in the quality of synthesized electrolyte. [ABSTRACT FROM AUTHOR]