In this talk we present recent results on the
effects of processing on the Li storage capacity of SWNTs. Electrochemistry and solid state nuclear
magnetic resonance measurements show that the reversible Li storage capacity of
purified SWNTs increased from LiC6 to LiC3 after
chemically etching. All the SWNTs become metallic upon Li intercalation with
the electronic density of state at the Fermi level increasing with increasing
Li concentration. We will also present results from electrochemical, x-ray and
Raman studies of Li reaction with nanostructured Si (n-Si). The energy barriers
for formation of Li-nSi alloys are significantly reduced. Reversible
electrochemical reaction takes place at room temperature, 400K below what is
possible for bulk Si. The high Li concentration and low electrochemical
potential with respect to Li/Li+ make n-Si attractive for Li storage
applications.
Work done in collaboration with B. Gao, H. Shimoda,
X.P. Tang, A. Kleinhammes, S. Sinha, L. Fleming, J. Owens, L.E. McNeil and Y.
Wu.