Novel Synthesis Process and Characterization of Li-Mn-O Spinels for Rechargeable Lithium Batteries

A new process has been developed for the synthesis of well-crystallized Li-Mn-O spinels with a homogeneous composition Li[Li x Mn 2-x ]O 4 (0.0≤x≤0.333) using the stoichiometry mixtures of lithium acetate and manganese nitrate as starting materials. The crystal structure of these compounds was studied with Rietveld refinements of the X-ray diffraction profiles. The lattice parameter of the spinels shows a strong dependence on the composition and manganese oxidation state. SEM micrographs indicate that the crystallites appear as single crystals. The size of the crystallites are in the range of 0.1 – 2μm, depending on the synthesis conditions. Samples with x≤0.125 show good electrode performance for the cell Li/Li 1+x Mn 2-x O 4 in the 4V region, whereas Li 4 Mn 5 O 2 (x=0.333) spinels show good cyclability with a rechargeable capacity of over 100mAh/g in the 3V region.