Electrochemical doping of bundles of unopened single wall carbon nanotubes

Electrochemical doping of bundles of unopened nanotubes with bisulfate ions (acceptor) and Lithium ions (donor) has been studied using coulometry and Raman spectroscopy. The interstitial channels between the tubes in the "rop e lattice" or bundles provide a new graphitic environment for intercalation . Using concentrated (18 M) sulfuric acid, a spontaneous charge-transfer re action is observed prior to the application of the electrochemical driving force, in sharp contrast to previous studies in graphite-H2SO4 system. Usin g Raman scattering, we were able to separate the spontaneous and electroche mical contributions to the overall charge transfer between the intercalant and the rope lattice.