Electrochemical performances of electrospun carbon nanofibers, interconnected carbon nanofibers, and carbon-manganese oxide composite nanofibers

This paper reported the comparison of electrochemical properties of carbon nanofibers (CNFs), interconnected carbon nanofibers (ICNFs), and carbon-manganese oxide composite nanofibers (C/MnO_x) fabricated by a conventional and a core-shell electrospinning technique, respectively, with the combination of heat treatment and CO₂- activation. Concerning material characterizations, the field emission scanning electron microscopy (FE-SEM) revealed the fiber-fiber interconnection patterns, the manganese oxide nanoparticles, and other fiber morphologies. Moreover, the FE-SEM results also exhibited the fiber diameters and particle sizes, which were consistent with the specific areas obtained from the N₂-adsorption/desorption techniques. The electrochemical performances were measured in aqueous electrolyte by three-electrode system. In addition, X-ray diffraction techniques (XRD) showed the phases of amorphous carbon, graphite structure, and manganese oxides, while the Raman analysis determined the carbon qualities in the samples. Furthermore, the differentiate-canning calorimetry (DSC) and the thermogravimetric analysis (TGA) displayed the thermal properties of all samples. As results, the C/MnO_x exhibited the greatest specific capacitance of 213.7 F g⁻¹ at the current density of 0.5 A g⁻¹ with the energy density of 30 mWh g⁻¹ at the power density of 249 mW g⁻¹ and the great cycling stability of 97% after 1000 cycles.