3-dimensional carbon nanotube for Li-ion battery anode

Abstract

Carbon nanotubes, in different forms and architectures, have demonstrated good promise as electrode material for Li-ion batteries, owing to large surface area, shorter Li-conduction distance and high electrical conductivity. However, practical application of such Li-ion batteries demands higher volumetric capacity, which is otherwise low for most nanomaterials, used as electrodes. In order to address this urgent issue, we have developed a novel 3-dimensional (3D) anode, based on multiwall carbon nanotubes (MWCNTs), for Li-ion batteries. The unique 3D design of the electrode allowed much higher solid loading of active anode material, MWCNTs in this case and resulted in more amount of Li+ ion intake in comparison to those of conventional 2D Cu current collector. Though one such 3D anode was demonstrated to offer 50% higher capacity, compared to its 2D counterpart, its ability to deliver much higher capacity, by geometrical modification, is presented. Furthermore, deposition of amorphous Si (a-Si) layer on the 3D electrode (a-Si/MWCNTs hybrid structure) offered enhancement in electrochemical response. Correlation between electrochemical performances and structural properties of the 3D anodes highlights the possible charge transfer mechanism.This research was, in part, supported by WCU (World Class University) program through the Korea Science and Engineering Foundation funded by the Ministry of Education, Science and Technology (R31-2008-000-10092) and AFOSR Grant (FA9550-09-1-0544)