Electronic spin transition in nanosize stoichiometric lithium cobalt oxide

Danna Qian; Yoyo Hinuma; Hailong Chen; Lin-Shu Du; Kyler J Carroll; Gerbrand Ceder; Clare P Grey; Ying S Meng

doi:10.1021/ja300868e

Electronic spin transition in nanosize stoichiometric lithium cobalt oxide

J Am Chem Soc. 2012 Apr 11;134(14):6096-9. doi: 10.1021/ja300868e. Epub 2012 Mar 28.

Authors

Danna Qian¹, Yoyo Hinuma, Hailong Chen, Lin-Shu Du, Kyler J Carroll, Gerbrand Ceder, Clare P Grey, Ying S Meng

Affiliation

¹ Department of NanoEngineering, University of California San Diego, La Jolla, California 92109, USA.

PMID: 22448963
DOI: 10.1021/ja300868e

Abstract

A change in the electronic spin state of the surfaces relevant to Li (de)intercalation of nanosized stoichiometric lithium cobalt oxide LiCo(III)O(2) from low-spin to intermediate and high spin is observed for the first time. These surfaces are the ones that are relevant for Li (de)intercalation. From density functional theory calculations with a Hubbard U correction, the surface energies of the layered lithium cobalt oxide can be significantly lowered as a consequence of the spin change. The crystal field splitting of Co d orbitals is modified at the surface due to missing Co-O bonds. The electronic spin transition also has a significant impact on Co(III)-Co(IV) redox potential, as revealed by the change in the lithium (de)intercalation voltage profile in a lithium half cell.