Preparation of spherical nanostruetured particles of lithium manganese oxides by a spray pyrolysis and fluidized bed hybrid system

A novel technique has been developed to directly produce fine ceramic powders from liquid solution using a spray pyrolysis and fluidized bed hybrid system. Using this technique, lithium manganese oxides, LiMn₂O ₄, which are the active cathode materials for lithium ion battery, have been prepared at various gas flow rates and static bed height. The effect of gas flow rate and static bed height on the powder properties is investigated with X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and the Brunauer-Emmett-Teller (BET) method. Lithium manganese oxides with several micron sizes and phase-pure cubic spinel are successfully synthesized for various gas flow rates and static bed height. Also, the as-prepared powders are spherical in shape. The crystallite size and specific surface area of the powders are strongly affected by the static bed height and gas velocity. In comparison with the conventional spray pyrolysis technique, the larger crystallite size and the smaller specific surface area of lithium manganese oxides powders are fabricated by using this technique. An as-prepared sample is then used as cathode active materials for lithium-ion battery and their cycle performance is also discussed.