Regulating the interfacial behavior of carbon nanotubes for fast lithium storage

Abstract Carbon nanotubes (CNTs) have been recognized as a versatile platform to integrating with various electroactive materials for boosting the comprehensive electrochemical performance. However, CNTs with distinct interfacial characters may play different roles in the subsequent lithiation/delithiation process. Accordingly, systematically engineering the interface of CNTs on the lithium storage behavior is of fundamental significance but remains rare. Herein, the lithium storage performance of boron-doped carbon nanotubes (B-CNT), acid activated carbon nanotubes (aCNT) and commercial carbon nanotubes (CNT) have been systematically studied. We demonstrate that the B-CNT features as a prominent fast charging anode in terms of excellent rate performance and long cycling stability at large current density (an average Coulombic efficiency of 99.8% can be achieved at a high current density of 10 A g−1). The electrochemical kinetic analyses indicate pseudo-capacitance dominated mechanism of B-CNT leads to faster electron/ion transport kinetics. In-depth theoretical simulation suggests that moderate lithium adsorption energy of B-CNT is important to balance the adsorption and release of Li ions, thus resulting fast lithium storage capacity. As a verification, the composite electrode with B-CNT as additive and silicon as anode material also shows outstanding rate performance. Therefore, these basic researches can provide valuable guidance for reasonable design of CNTs-based composite electrode materials toward high-rate batteries.