Nanocomposites of Graphene Nanosheets/Multiwalled Carbon Nanotubes as Electrodes for In-plane Supercapacitors

Flexible supercapacitors with large power and energy densities, long life cycles and good operational safety are necessary devices for various applications. In this work, we demonstrate the integration of a composite based on graphene nanosheets/multiwalled carbon nanotubes in an in-plane supercapacitor configuration by using a straightforward preparation involving the filtration of nanomaterials to produce an electrode film. Reduced graphene oxide (RGO) received 15 wt % carbon nanotubes to act as a conducting additive, which led to a flexible and transferable thin film (RGO/MW) with an average conductivity of 20.0 S cm−1. Three ionic liquids were tested as electrolytes for the supercapacitor, among which 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI) was observed to exhibit the best performance. The specific capacitance of the supercapacitor based on RGO/MW-EMITFSI reached 153.7 F g−1 at a current density of 0.2 A g−1 and exhibited a capacitance retention of 88% after 2000 cycles. The maximum energy and power densities were calculated to be 41.3 Wh kg−1 and 3.5 kW kg−1, respectively, for the RGO/MW-EMITFSI supercapacitor.

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