3 dimensional carbon nanostructures for Li-ion battery anode

Abstract

Carbon nanofibers (CNFs) have been thoroughly investigated as potential anode materials in Li-ion battery owing to their exceptional properties such as the higher surface area to mass ratio, electrical conductivity and mechanical toughness. However, one of the major limitations of nano carbon materials is lower mass loading density. To address this issue, we have developed a novel anode system composed of CNFs directly grown on 3D Cu mesh current collector (hereafter mentioned as 3D CNFs) using a thermal catalytic chemical vapor deposition (CVD) method. Compared to CNF-based anodes on 2D Cu current collector, active The active material loading amount of the 3D CNFs has been found to be 400 % higher while comparing with 2D CNF. Owing to an increase of the active surface area, 3D CNFs demonstrated enhanced electrochemical performance of Li-ion battery in terms of charge capacity (50% improvement), rate capability and cycling life. Interfacial contact between the CNFs and Cu could play a crucial role in promoting the electrochemical properties. The intermediate TiC thin layer, formed at high temperature 750°C, could function as an efficient electric conducting pathway and a strong bonding bridge between the CNFs and Cu. In order to improve the pristine 3D CNF redox reactions, the amorphous Si (a-Si)/3D CNF has been sputter deposited to produce Si wrapped 3D CNF hybrid anode material. It has been found that the electrochemical properties of the a-Si/3D CNF yields superior specific capacity (Cdis549 mAhg-1, LiC4.1) and cycling stability than that of pristine 3D CNF (461 mAhg-1, LiC4.8).