(8b) Preparation of Spherical Nanostructured 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, LiMn₂O₄, which are one of the
active cathode materials for lithium ion battery, has 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.