Conjugation with carbon nanotubes improves the performance of mesoporous silicon as Li-ion battery anode

Abstract

Carbon nanotubes can be utilized in several ways to enhance the performance of silicon-based anodes. In the present work, thermally carbonized mesoporous silicon (TCPSi) microparticles and single-walled carbon nanotubes (CNTs) are conjugated to create a hybrid material that performs as the Li-ion battery anode better than the physical mixture of TCPSi and CNTs. It is found out that the way the conjugation is done has an essential role in the performance of the anode. The conjugation should be made between negatively charged TCPSi and positively charged CNTs. Based on the electrochemical experiments it is concluded that the positive charges, i.e., excess amine groups of the hybrid material interfere with the diffusion of the lithium cations and thus they should be removed from the anode. Through the saturation of the excess positive amine groups on the CNTs with succinic anhydride, the performance of the hybrid material is even further enhanced.