TY - JOUR
T1 - Excess Li ions in a small graphite cluster
AU - Nakadaira, M.
AU - Saito, R.
AU - Kimura, T.
AU - Dresselhaus, G.
AU - Dresselhaus, M. S.
N1 - Funding Information:
The authors gratefully acknowledge useful discussions with Professor M. Endo and Professor T. Enoki, and with M. J. Matthews. The present collaborative research is funded in part by the International Joint Research Program of the New Energy and Industrial Technology Organization (NEDO), Japan. The authors thank the Supercomputer Center, Institute for Solid State Physics, University of Tokyo for the facilities and the use of the FACOM VPP500. Part of the work by RS is supported by a Grant-in Aid for Scientific Research (B) (No. 08454079) from the Ministry of Education, Science and Culture, of Japan. The MIT work was partly supported by the NSF (DMR 95-10093) and by the Lawrence Livermore National Laboratory through subcontract (No. B287707).
PY - 1997/5
Y1 - 1997/5
N2 - We calculate the optimized geometry and the corresponding electronic structure of Li ions doped in a small graphite cluster with dangling bonds or hydrogen terminations at the edge surrounding the cluster. The calculations imply both covalent and ionic bonds of Li ions to carbon atoms, which may be relevant to explaining the broad signal of the 7Li NMR Knight shift spectra. Li intercalation, in particular, is possible even at the hydrogen-terminated edges. Because of the finite size effect of the cluster, the ionicity of intercalated Li ions has a large distribution of values, ranging from positive values close to that in graphite intercalation compounds to even slightly negative values, depending on the bonding geometry. We propose that the cluster edge surface plays a special role in accommodating excess Li ions in the disordered graphite system.
AB - We calculate the optimized geometry and the corresponding electronic structure of Li ions doped in a small graphite cluster with dangling bonds or hydrogen terminations at the edge surrounding the cluster. The calculations imply both covalent and ionic bonds of Li ions to carbon atoms, which may be relevant to explaining the broad signal of the 7Li NMR Knight shift spectra. Li intercalation, in particular, is possible even at the hydrogen-terminated edges. Because of the finite size effect of the cluster, the ionicity of intercalated Li ions has a large distribution of values, ranging from positive values close to that in graphite intercalation compounds to even slightly negative values, depending on the bonding geometry. We propose that the cluster edge surface plays a special role in accommodating excess Li ions in the disordered graphite system.
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U2 - 10.1557/JMR.1997.0186
DO - 10.1557/JMR.1997.0186
M3 - Article
AN - SCOPUS:0031145633
SN - 0884-2914
VL - 12
SP - 1367
EP - 1375
JO - Journal of Materials Research
JF - Journal of Materials Research
IS - 5
ER -