Hierarchically Structured Nitrogen-Doped Multilayer Reduced Graphene Oxide for Flexible Intercalated Supercapacitor Electrodes

Intercalated flexible electrodes for energy storage devices have drawn significant research interests as they can provide high energy densities for powering electronics without sacrificing the overall flexibility. Herein, we report an intercalated reduced graphene oxide/polyacrylonitrile (rGO/PAN) flexible supercapacitor electrode fabricated via a layer-by-layer wet electrospinning (LLwES) process with diluted graphene oxide (GO) solution as the coagulation liquid and subsequent thermal reduction treatment. It was observed that a thin GO film was established on individual PAN nanofiber layer after the wet electrospinning process, while the subsequent thermal reduction of GO led to simultaneous stabilization of the PAN fibers and the creation of an interesting three-dimensional hierarchical carbon nanostructure suitable for flexible, high-performance electrochemical capacitor (EC) electrodes. The formation of gases during the thermal treatment expanded the electrospun PAN fiber layers and resulted in the formation of intercalated nitrogen-doped porosities. The resulting LLwES rGO/PAN system, thermally treated in a nitrogen atmosphere, demonstrated exceptional double-layer capacitance of 221 F/g at 10 mV/s, a controllable electrical conductivity of 125 S/m, and a stable cycling performance retaining a slightly increased capacitance after 10000 cycles.