Acetylation Strategy for Unzipping Carbon Nanotubes in High-Performance Lithium-Ion Batteries

Although carbon nanotubes (CNTs) have attracted tremendous attention as the lithium-ion battery (LIB) anode material considering their excellent electrochemical and mechanical properties, their low theoretical specific capacity severely limits the practical applications. The high specific capacities of organic carbonyl compounds in LIBs can be introduced to increase the specific capacity of CNTs. However, the inherent electrical insulating properties and low utilization of active sites of organic carbonyl compounds, as well as a high solubility in aprotic electrolytes, are severe concerns. Herein, we report a strategy of combining organic acetyl groups on unzipped CNTs (UCNTs) to address above issues, which not only tackles the poor conductivity and rapid dissolution of small organic molecules but also improves the specific capacity of CNTs. Acetylated UCNTs (AcUCNTs) display an admirable electrochemical performance in LIBs, with the first cycle discharge and charge capacities reaching 987.1 and 875.2 mA h g-1 at 200 mA g-1, respectively. More impressively, AcUCNTs retains a high capacity of 540.0 mA h g-1 after 87 cycles, which is dramatically higher than that of pristine CNTs. This research is important for providing a technology for combining organic and inorganic materials to achieve superior electrode materials, which is significant in the development of LIBs.