Studies on a novel Na+ superionic conducting polymer gel cocktail electrolyte membrane immobilizing molecular liquid mixture of carbonates, tetraglyme and ionic liquid

Abstract Novel Na+ superionic conducting polymer gel cocktail electrolyte membranes immobilizing molecular liquid mixture of carbonates, tetraglyme and ionic liquid have been prepared by solution cast method. The optimized free standing electrolyte membrane offers ionic conductivity of 3.3 × 10-3 S cm−1 and sodium-ion transport number of 0.31 at ambient temperature. The detailed ion-dynamics have been investigated with the help of frequency dependent dielectric and modulus studies. The possible interaction of these molecular liquids with sodium tetrafluoroborate salt and poly(vinylidiene fluoride-hexafluoropropylene) polymer host is investigated by FTIR studies. The DSC study confirms that the electrolyte system maintains the gel phase up to ~ 120 °C. The linear sweep voltammetry reveal the working voltage range offered by the electrolyte system to be 3.46 V. The Electric double layer capacitor (EDLC) cell with optimized electrolyte membrane and electrodes of activated carbon demonstrate the specific discharge capacity of ~ 60F g−1 and drops negligibly with cycle number. The reported Na+ superionic conducting cocktail electrolyte system can be utilized as an electrolyte while fabricating electrochemical devices especially the EDLCs.