Solid-state electrical double layer capacitor using Li-salt incorporated ionic liquid based gel polymer electrolyte and gelled multi-walled carbon nanotubes electrodes

The present investigation is focused on the solid-state supercapacitors which are fabricated with ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (BMPTFSI) modified multiwalled carbon nanotube (MWCNT) electrodes and ionic liquid incorporated gel polymer electrolyte (ILGPE). Furthermore, the incorporation of the Li-salt lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) in ILGPE has been done and the effect of the Li-salt on the performance of supercapacitorsis investigated. On the addition of Li-salt, a wider electrochemical window of ∼ 3 V is found at room temperature. The impact of the Li-salt in the gel polymer electrolyte and comparative performance with the EDLCshave been studied byusing electrochemical impedance spectroscopy, cyclic voltammetric, and galvanostatic charge–discharge studies. It is found that bucky gelled MWCNT electrodes provide specific capacitance of ∼ 57 F/g with Li-salt incorporated ILGPE, which is higher as compared to ILGPE without Li-salt, showing the value of 51 F/g which as also reflect in CV profiles.