Nanospace-Assisted Anti-Oxidative Li Storage on Carbon Nanotubes

Abstract

Lithium (Li) metal has attracted significant interest as a next-generation battery anodes due to its high theoretical specific capacity and low redox potential. However, inhomogeneous plating/stripping behavior of Li metal accelerates Li-consuming parasitic reaction and sometimes provokes an internal short circuit problem. In particular, its environmental vulnerability (e.g., notorious reactivity upon exposure to air and water) due to the electrochemical instability poses a formidable challenge to commercial applications, thus it should be resolved as an indispensable prerequisite in addition to resolving the concerns on cell performance and safety.Here, we report a new class of anti-oxidative Li reservoir based on nanospaces of carbon nanotube (CNT) bundles. The CNT bundles are formed by assembling themselves via van der Waals interactions, producing one-dimensional nanospaces (i.e., external grooves and interstitial channels). The Li preferentially stored in the interstitial channels is chemically stable against to air and water. Notably, the Li electrochemically extracted from Li-confined CNTs onto a copper (Cu) foil prohibits reliable electrochemical performance (e.g., stable charge/discharge behavior) comparable to those of pristine Li foils. We envision that this nanospace reservoir strategy will open a new avenue for development of environmentally tolerant, high-capacity Li storage.