An investigation of the Li1+δMn2−δO4 cathode material for rechargeable lithium ion batteries Part I: Composition and structure analyses

The Hunterʹs chemical delithiating process has been applied for the first time to produce Li+-extracted materials from δ spinel lithium manganese oxides. The composition and structure of these Li+-extracted materials have been analyzed by X-ray diffraction (XRD), infra-red spectroscopy (IR) and atomic absorption spectroscopy techniques. The results show that these Li+-extracted materials keep cubic symmetry structure and the host framework Mn2−δO4 of the starting material, Li1+δMn2−δO4 (δ=0.044). However, somewhat contraction of the framework occurs during the delithiating process and thus the lattice parameter, a, changes regionally with the lithium content in Li+-extracted materials. Furthermore, the present work demonstrates that the amount of lithium ions in octahedral sites remain intact.