Electronic structure and stability of the LixMn2O4 (0 < x < 2) system

Abstract

LMTO-ASA self-consistent band structure calculations have been performed for the cubic spinel LiMn₂O₄ and its delithiated and lithiated phases: λ-MnO₂ and Li₂Mn₂O₄. It has been shown that the Jahn–Teller distortion plays a vital rôle in the stabilisation of the Li₂Mn₂O₄ phase. The influence on the band structure of different possible positions for the lithium ions is investigated, and the phase transition from cubic to tetragonal symmetry for Li₂Mn₂O₄ discussed. The change in potential associated with the insertion of lithium ions into λ-MnO₂ to form LiMn₂O₄ and Li₂Mn₂O₄ has been calculated as 1.51 V and 1.16 V, respectively. The lithium atoms are ionised by contributing substantial character to the bonding band. However, the charge transfer is small and the electron density around the lithium ions is higher than in lithium metal.