Local structure of lithiated manganese oxides

This work presents the vibrational features of lithiated manganese oxides used as positive electrode materials in lithium-ion batteries. Vibrational spectroscopies (Raman and FTIR) yield reliable description of material lattice by probing the distortion of the basal MnO6 octahedra in these oxides. Lattice dynamics are studied using either a classical group theoretical analysis or a local environment model. The local arrangement in MnO2 structures is investigated including the lithiated Li0.33+xMnO2 (0 <= x <= 0.6) phase. The phase evolution as a function of the degree of lithium intercalation or deintercalation is reported and analyzed in a series of manganospinels Li1-x+yMn2-yO4 with 0 <= x <= 1 and 0 <= y <= 0.33. A comparison with tetragonal Li2Mn2O4 and Li-6.6Mn5O12 spinels shows the influence of the Jahn-Teller effect on the Raman features for this class of materials. A relationship between the cubic lattice parameter and the infrared mode frequency is also established. (c) 2005 Elsevier B.V. All rights reserved.