Amorphous Cobalt Carbon Nanofibers Decorated with Conductive Ag as Free-Standing Flexible Electrode Material for High-Performance Supercapacitors

Abstract

Carbon nanofiber-based amorphous cobalt oxide (CoxOy/CNFs) embedded with Ag have been prepared by a simple electrospinning technique followed by heat treatment. Because the composite material prepared by this method showed good flexibility, addition of a conductive agent and binder is not required for use as an electrode material in supercapacitors. The Co-Ag/CNFs composite materials exhibited remarkably improved electrical conductivity and specific capacitance with good cycling stability in comparison with electrodes based on CoxOy/CNFs, owing to the presence of Ag; For instance, the Co-Ag/CNFs(2) composite electrode exhibited specific capacitance of 698 F g−1 at 1 A g−1 and good cycling stability with ∼ 81.1% capacitance retention over 3000 cycles. The composite materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD) analysis, Raman spectra, and thermogravimetric analysis (TGA), confirming successful combination of the amorphous cobalt oxide and silver metal element with the carbon nanofibers.