Design and Fabrication of Solid-State Electrolytes for Supercapcitor Applications

Abstract

Fabricating solid-state electrolytes with high conductivity and superior mechanical properties for wearable electronic applications is highly desirable. In this study poly (1-butyl 3-vinyl imidazolium tetrafluoroborate) polyionic liquid (PIL) has been synthesized and incorporated into 1-ethyl 3-methyl imidazolium tetrafluoroborate ionic liquid (IL) in various ratios. Additionally, gel polymer electrolytes (GPEs) have been synthesized at different crosslinking densities. Rheological analysis indicated that the storage modulus and dynamic viscosity of the GPE with the highest crosslink density increased by 7 and 6 orders of magnitude respectively. Also, crosslinking transforms the response of synthesized electrolytes from liquid viscoelastic to solid viscoelastic-like behavior. Electrochemical characterization illustrated that the specific capacitance of the SCs devices dropped down from 109 F.g-1 for the pure IL to 66 and 56 F.g-1 for IL-PIL mixtures and GPEs respectively. Considering the storage modulus improvement this trade-off is more efficient for GPEs due to the polymer network formation. Finally, GPEs were synthesized in situ inside of the reduced graphene oxide (rGO) electrodes, and the storage modulus of the GPEs synthesized in-situ in the rGO electrodes increased from 11 kPa to 102 kPa to be considered for real-life applications.