Chapter Seven - Synthesis and Electrochemical Performance of Transition Metal-Coated Carbon Nanofibers on Ni Foam as Anode Materials for Lithium Secondary Batteries

Abstract

As a new generation of green rechargeable batteries, the lithium ion secondary battery has many advantages over other candidates, such as better portability, higher energy density, longer cycle life, and nonmemory effect, etc. It is widely used not only in the electronic products, small electric tools, aerospace instruments, and related industries, but also as one of the backup power supplies for electric vehicles, which attracts widespread concerns around the world. The electrode material is an important component of a lithium ion battery, and its research has been a crucial role as one of the key subsystems for the development of the lithium-ion battery. In this study, transition metal-coated carbon nanofibers (CNFs) were synthesized and applied as anode materials of Li secondary batteries. Carbon nanofibers/Ni foam was dipped into 0.01M transition metal solutions after growing carbon nanofibers on Ni foam via the chemical vapor deposition (CVD) method. The transition metal-coated carbon nanofibers/Ni foam was dried in an oven at 80°C. The morphologies, compositions, and crystal quality of carbon nanofibers/transition metal composites were characterized by scanning electron microscopy (SEM), Raman spectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS). The electrochemical characteristics of carbon nanofiber/transition metal composites as anodes of Li secondary batteries were investigated using a three-electrode cell. The transition metals/carbon nanofibers/Ni foam was directly employed as a working electrode without any binder, and lithium foil was used as both the counter and reference electrodes. 1M LiClO4 was employed as the electrolyte and was dissolved in a mixture of propylene carbonate:ethylene carbonate (PC:EC) at a 1:1 volume ratio. The galvanostatic charge/discharge cycling and cyclic voltammetry measurements were taken at room temperature using a battery tester.