a1 Center for Autonomous Solar Power (CASP), Binghamton University, State University of New York, Binghamton, NY, 13902, USA
a2 Department of Electrical and Computer Engineering, Binghamton University, State University of New York, Binghamton, NY, 13902, USA
Graphene-based all-solid-state supercapacitors the using ionic liquid gel polymer electrolyte have been fabricated and characterized. The gel polymer electrolyte has been prepared by immobilizing ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) with poly(vinylidene fluoride-hexafluoropropylene). Cyclic voltammetry studies show highly capacitive behavior under fast scan rates. Impedance analysis show nominal charge transfer and ion diffusion at pores related resistance contributions. The graphene-based solid-state supercapacitor shows optimum capacitance of 80 mF cm-2 (equivalent to the single electrode specific capacitance of 76 F g-1). This corresponded to the specific energy of 7.4 Wh kg-1 and specific power of 4.5 kW kg-1. The supercapacitor cell shows stable cyclic performances for up to 5000 cycles and possibly beyond.