Aligned carbon nanotubes for lithium-ion batteries: A review

Nanoscale materials are gaining massive attention in recent years due to their potential to alleviate the present electrochemical electrode constraints. Possessing high conductivity (both thermally and electrically), high chemical and electrochemical stability, exceptional mechanical strength and flexibility, high specific surface area, large charge storage capacity, and excellent ion-adsorption, carbon nanotubes (CNTs) remain one of the most researched of other nanoscale materials for electrochemical energy storage. Rather than having them packed at random, CNTs perform better when packed/grown to order, vertically or horizontally aligned to a substrate. This study presents an overview of the impact of CNT alignment on the electrochemical performance of lithium-ion batteries (LIBs). The unique properties of vertically aligned CNTs (VACNTs) for LIB application were discussed. Furthermore, the mechanisms of charge storage and electrochemical performances in VACNT-based (pristine and composites) anodes and cathodes of LIBs were succinctly reviewed. In the end, the existing challenges and future directions in the field were also briefly discussed.