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

Abstract

Nano-composite polymer gel electrolyte (NCPGE) films are prepared by incorporating liquid electrolyte (EC-PC-TEABF4) 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-TEABF4}]. Highest conductivity of 8.2 × 10−3 Scm−1 is found for optimized composition [(1:4){PVDF-HFP + EC-PC-TEABF4} + SiO2 (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.