Synthesis and electrochemical performance of transition metal-coated carbon nanofibers as anode materials for lithium secondary batteries

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) 2018, 68(0), , pp.161-167
• Main Authors: Choi, Jin-Yeong, Hyun, Yura, Park, Heai-Ku, Lee, Chang-Seop
• Format: Article
• Language: English
• Subjects: Anode; Carbon nanofibers; Chemical vapor deposition; Lithium secondary batteries; Transition metals; 화학공학
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2018.07.041

[Display omitted] •Four transition metal (Fe, Co, Ni and Cu) coated carbon nanofibers (CNFs) were synthesized and applied as anode materials of Li secondary batteries.•When CNFs-Fe was used as the anode active material, after 30 cycles, the initial capacity of CNFs-Fe was increased by 78% compared to that of CNFs. Among the four transition metals, the retention rate of CNFs-Fe was the highest at 41%.•The uniformly coated transition metal on CNFs improved the low charge/discharge capacity of the lithium secondary battery by increasing the electric conductivity of the surface and improved the retention rate by inhibiting the undesirable side reactions between the electrode and electrolyte. In this study, transition metal coated carbon nanofibers (CNFs) were synthesized and applied as anode materials of Li secondary batteries. CNFs/Ni foam was immersed into 0.01M transition metal solutions after growing CNFs on Ni foam via chemical vapor deposition (CVD) method. Transition metal coated CNFs/Ni foam was dried in an oven at 80°C. Morphologies, compositions, and crystal quality of CNFs-transition metal composites were characterized by scanning electron microscopy (SEM), Raman spectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS), respectively. Electrochemical characteristics of CNFs-transition metal composites as anodes of Li secondary batteries were investigated using a three-electrode cell. Transition metal/CNFs/Ni foam was directly employed as a working electrode without any binder. Lithium foil was used as both counter and reference electrodes while 1M LiClO4 was employed as the electrolyte after it was dissolved in a mixture of propylene carbonate:ethylene carbonate (PC:EC) at 1:1 volume ratio. Galvanostatic charge/discharge cycling and cyclic voltammetry measurements were taken at room temperature using a battery tester. In particular, the capacity of the synthesized CNFs-Fe was improved compared to that of CNFs. After 30 cycles, the capacity of CNFs-Fe was increased by 78%. Among four transition metals of Fe, Cu, Co and Ni coated on carbon nanofibers, the retention rate of CNFs-Fe was the highest at 41%. The initial capacity of CNFs-Fe with 670mAh/g was reduced to 275mAh/g after 30 cycles.