Graphene/polypyrrole-coated carbon nanofiber core–shell architecture electrode for electrochemical capacitors

Abstract

Herein, we report a two-step electrospinning and potentiostatic electrodeposition method to fabricate electrodes with graphene/polypyrrole-coated carbon nanofiber core–shell architecture for supercapacitor applications. The electrospun carbon nanofiber core acts as an electrically conductive substrate that enables the incorporation of the graphene/polypyrrole shell. Constructing a porous and interconnected one-dimensional configuration with a carbon nanofiber core facilitates the maximum electrochemical utilization of the graphene/polypyrrole shell. The addition of graphene significantly decreases the charge transfer resistance of the electrode by reducing the distance for electron shuttling in the polypyrrole chains for rapid electrochemical redox reactions. As a consequence, the specific capacitance of the core–shell electrode was enhanced up to 386 F g⁻¹ at 2 mV s⁻¹. The enhanced conductivity and improved stability of the core–shell composite electrode is able to retain 84% of its initial capacitance value over 1000 charge/discharge cycles. The excellent electrochemical performance demonstrates that electrodes with a graphene/polypyrrole-coated carbon nanofiber core–shell architecture have great potential in electrochemical energy conversion and storage devices.