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

Abstract

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.