Oxygen-driven surface segregation of lithium from single-wall carbon nanotubes

We have investigated the effects of oxygen exposure on lithium-intercalated single-wall carbon nanotube bundles at room temperature, and the evolution of surface configuration versus temperature. X-ray and ultraviolet photoelectron spectroscopy measurements show a remarkable increase of surface lithium concentration, associated to modifications suffered by both core-level O 1 s line shape and valence band spectra. These results have been attributed to the occurrence of lithium surface segregation induced by interaction with oxygen species. Moreover, lithium oxide and peroxide related features are observed indicating that lithium oxidation takes place at the nanotube bundle surface.