Transition metal/porous carbon composite is good electrode candidate since porous carbon provides high surface porosity which promotes the access of electrolyte ions, and transition metal enables redox reactions to improve specific capacitance and energy density. In this study, iron/carbon nanofiber (CNF) composite electrodes were prepared by grafting ferrocenecarboxaldehyde to the CNFs which were fabricated by electrospinning and thermal treatment of polyacrylonitrile (PAN). The presence of iron on the CNF surface was confirmed by SEM/EDS, ICP-MS and XPS. Electrochemical performance was evaluated using a three-electrode cell with 1 M Na2SO4 as an electrolyte. Iron-grafted CNFs exhibited a high specific capacitance of 358 F g− 1 and an energy density of 49.7 Wh kg− 1 at 0.5 A g− 1, which is significantly higher than those for untreated CNFs (68 F g− 1 and 9.4 Wh kg− 1). This demonstrates that this iron/CNF composite is promising candidate for supercapacitor electrode with outstanding energy storage performance.

Preparation of ironcarbon composite by grafting ferrocene to carbon nanofibers for supercapacitor electrodes
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Preparation of CNFs
        2.3 Characterization of CNFs
        2.4 Measurement of electrochemical properties
    3 Results and discussion
        3.1 Characteristics of Fe-CNFs
        3.2 Electrochemical performance Fe-CNF electrodes
    4 Conclusions
    Acknowledgements 
    References

• Seung Ah Kim(Department of Advanced Materials and Chemical Engineering, Daegu Catholic University, Gyeonsan‑si, Gyeonbuk, Republic of Korea)
• Kyung‑Hye Jung(Department of Advanced Materials and Chemical Engineering, Daegu Catholic University, Gyeonsan‑si, Gyeonbuk, Republic of Korea) Corresponding author
• Kyeng Min Park(Department of Biochemistry, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea)