Solid-state supercapacitors with ionic liquid gel polymer electrolyte and polypyrrole electrodes for electrical energy storage

Abstract

In this work, solid-state supercapacitors with ionic liquid gel polymer electrolyte and polypyrrole symmetrical electrodes were fabricated and characterized. The ionic liquid 1-butyl-3methylimidazolium tetrafluoroborate (BMIBF4) was mixed with poly (vinylidene fluoridehexafluoropropylene) P(VdF-HFP) to form gel electrolyte. The polypyrrole electrode was prepared by ultra-short pulsed current electro-polymerization over flexible graphite sheets, and was synthesized using LiClO4 and H2SO4 electrolytes. Both electrodes were conditioned by using cyclic voltammetry (CV) for approximately 20 cycles before electrochemical testing. The single electrodes produced maximum area capacitance densities of 403.23mFcm−2 and 336.08mFcm−2, synthesized in H2SO4 and LiClO4 electrolytes, respectively at a scan rate of 10mVs−1. The electrochemical performance of the PPy solid-state supercapacitor was evaluated using CV, CD, and EIS with a maximum area capacitance density of 31.84mFcm−2 (equivalent to a specific capacitance of 19.9F g−1)obtained from EIS for the supercapacitor synthesized in H2SO4. The specific energy and specific power were evaluated from CD and were found to be 0.143Whkg−1 and 6.39kWkg−1, respectively at 3mAcm−2.