Ab initio studies of structural and electronic properties of Li4Ti5O12 spinel

Structural and electronic properties of Li4Ti5O12 spinel are studied from density functional theory based first principles calculations. Differences on these properties between delithiated state Li4Ti5O12 and lithiated state Li7Ti5O12 are compared. The optimized lattice constant of Li4Ti5O12 is 8.619 Å, which is even a little larger (0.2%) than 8.604 Å of the lithiated state Li7Ti5O12. The arrangement of the Li and Ti atoms at the 16d sites of the spinel structure is also investigated in a cubic unit cell. Large 1 × 1 × 3 supercell models are constructed and used to calculate the total energy and electronic structure. The average intercalation potential is also calculated, with metallic lithium as reference.