Influence of corannulene's curved carbon lattice (C{sub 20}H{sub 10}) on lithium intercalation
Ab initio molecular orbital calculations have been used to investigate the influence of corannulene's curved carbon lattice (C{sub 20}H{sub 10}) on lithium intercalation. This has been approximated by investigating the reaction of lithium atoms with either the corannulene molecule directly or with a sandwich structure formed from two corannulene molecules. In the first case, one corannulene molecule, three, six and seven lithiums have been used to form Li{sub 3}(C{sub 20}H{sub 10}), Li{sub 6}(C{sub 20}H{sub 10}) and Li{sub 7}(C{sub 20}H{sub 10}). The last complex has a lithium to carbon ratio of 1:2.86 indicative of a high capacity lithium carbon anode versus the 1:6 ratio found in stage 1 lithium intercalated graphite. The change in Gibbs energy for formation of Li{sub 3}(C{sub 20}H{sub 10}) with a multiplicity of 4 (3 unpaired electrons) is {minus}4.75 kcal/mole. However, when a multiplicity of 2 is used (1 unpaired electron), the change in Gibbs energy is {minus}8.49 kcal/mole. The change in Gibbs energy for formation of Li{sub 6}(C{sub 20}H{sub 10}) and Li{sub 7}(C{sub 20}H{sub 10}) (multiplicity of 2) are {minus}26.48 and {minus}26.47 kcal/mole, respectively. In all the lithium corannulene complexes described, each complex has a molecular orbital composed only of lithium orbitals, indicative of lithium cluster formation. However, in the formation of Li{sub 3}(C{sub 20}H{sub 10}){sub 2} with three lithium atoms intercalated between two corannulene carbon lattices, there are no molecular orbitals indicative of lithium cluster formation. The multiplicity for this chemical system is 4 and the corannulene lattices are stacked one over the other like saucers. The corannulene carbon lattices are separated by approximately 4.5 {angstrom}. The separations between lithiums are 3.13, 3.60 and 3.79 {angstrom}. These results are in contrast to those found in the Li{sub 3}C{sub 60} endohedral complex with a multiplicity of 4. In this complex there is a molecular orbital composed only of lithium orbitals. The calculated results in this investigation suggest that the carbon lattice stacking configuration is important for lithium cluster formation. For Li{sub 6}(C{sub 20}H{sub 10}), a transition state intermediate complex has been found through the geometry optimization process. Optimization of this structure results in a complex which is 13.42 kcal/mole more stable. These preliminary results indicate that the energy of activation for the removal of one lithium from this complex is on the order of 13.42 kcal/mole or 0.58 Ev.
- Research Organization:
- Research Lab., Wright-Patterson AFB, OH (US)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 20002739
- Resource Relation:
- Conference: 33rd Intersociety Energy Conversion Engineering Conference, Colorado Springs, CO (US), 08/02/1998--08/06/1998; Other Information: 1 CD-ROM. Operating system required: Windows 3.x; Windows 95/NT; Macintosh; UNIX. All systems need 2X CD-ROM drive.; PBD: 1998; Related Information: In: Proceedings of the 33. intersociety energy conversion engineering conference, by Anghaie, S. [ed.], [2800] pages.
- Country of Publication:
- United States
- Language:
- English
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