Carbon nanotubes-zeolite complex: A Li-intercalated compound with high storage capacity

We report a composite system for Li intercalation, in which ultrasmall-diameter (4 Angstrom) carbon nanotubes are confined inside the channels of nanoporous zeolite crystals. The first-principles pseudopotential calculations show that there are several possible sites for lithium to be intercalated, including the interior and exterior of the nanotubes. The vapor phase adsorption and electrochemical measurements both indicate that the lithium capacity of the system can be similar to10% by weight, which is higher than that of graphite intercalation compounds. The enhanced Li capacity makes the nanotubes-zeolite complex a plausible candidate for Li battery applications. (C) 2004 American Institute of Physics.