TITLE:
Graphene-Polymer Nanocomposites and Roll-to-Roll (R2R) Compatible Flexible Solid-State Supercapacitor Based on Graphene Nanoplatelets and Ionic Liquid-Polymer Gel
AUTHORS:
Jasper Chiguma, Eliud Mushibe, Natalya Gonopolskaya, Wayne E. Jones Jr
KEYWORDS:
Flexible Supercapacitors, Specific Capacitance, Graphene, Roll-to-Roll, Nanocomposites, Farads
JOURNAL NAME:
Graphene,
Vol.11 No.1,
December
24,
2021
ABSTRACT: We present the electrical and supercapacitive
performance of graphene nanoplatelets in polymer nanocomposites and flexible
solid state electrical double layer capacitors (EDLC) respectively.
Graphene-doped poly (3,4-ethylenedioxythiophene) (PEDOT) coated
polyethylene terephthalate (PET) and glass exhibited transmittance above 95%
and electrical conductivity of 2.70 × 10ˉ1 S·cmˉ1 and
9.01 × 10ˉ1 S·cmˉ1 respectively. Graphene loaded
polymethyl methacrylate (PMMA) and polystyrene (PS) nanocomposites showed
electrical conductivity as high as 2.11 × 10ˉ1 S·cmˉ1 at
low loadings of 2 wt%. The use of graphene was necessitated by the
need to increase the EDLC capacitance and energy density since it provides high
effective surface area. The polymer gel membrane made from polyvinylidene
fluoride-co-hexafluoropropylene (PVDF-co-HFP) and the Ionic Liquid (IL)
1-butyl-3-methylimidazolium hexafluorophosphate exhibited high porosity which
made it suitable for use as separator in the EDLC. The highest recorded specific capacitance was 133.82 F/g which can be attributed to
the porosity of the IL containing PVDF-co-HFP membrane and the large surface
area of the graphene electrodes. At an operating voltage of 3.5 V the energy
density was found to be 56.92 Wh·Kgˉ1. All chemicals were research
grade and were obtained from Sigma Aldrich.