Nitrogen-doped electrospun reduced graphene oxide-carbon nanofiber composite for capacitive deionization

A nitrogen-doped electrospun reduced graphene oxide-carbon nanofiber composite (NG-CNF) was fabricated via electrospinning by adding graphite oxide into a precursor solution and subsequent thermal treatment under an ammonia atmosphere. The morphology, structure and electrochemical performance of the composite were characterized by scanning electron microscopy, nitrogen adsorption-desorption, cyclic voltammetry and electrochemical impedance spectroscopy, and their capacitive and electrosorption performances in NaCl solution were studied. The NG-CNF composite electrode shows excellent specific capacitance (337.85 F g^-1) and electrosorption capacity (3.91 mg g^-1), much higher than those of pure carbon nanofibers (171.28 F g^-1 and 3.13 mg g^-1) and the reduced graphene oxide-carbon nanofiber composite (264.32 F g^-1 and 3.60 mg g^-1). The enhanced performance of the NG-CNF is ascribed to the nitrogen doping and the formation of an effective "plane-to-line" conducting network in the composite, which facilitates the electron transfer and ion transport as well as increases the specific surface area.