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LiNi0.5Mn1.5O4cathode materials were produced by spray pyrolysis apparatus using the flame combustion. SEM revealed that as-prepared powders had spherical morphology with porous microstructure which had an average diameter of about 2 μm with broad size distribution. After the calcination, LiNi0.5Mn1.5O4powders with polygonal morphology and narrow particle size distribution were obtained. XRD showed that LiNi0.5Mn1.5O4was well crystallized after the calcination at 900°C. Rechargeable measurement of LiNi0.5Mn1.5O4cathode showed that the long plateau was observed at 4.7 V in discharge curve of LiNi0.5Mn1.5O4cathode and its discharge capacity was 145 mAh/g at 1 C. The capacity retention of LiNi0.5Mn1.5O4cathode were 95% at 1 C after 100 cycles. The discharge capacity and capacity retention of LiNi0.5Mn1.5O4cathode were 125 mAh/g and 88% at 20 C. LiNi0.5Mn1.5O4cathode exhibited also stable cycle performance at 50C.

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Spherical LiFePO 4 /C powders were successfully produced at a rate of 100 g/h using a large type spray pyrolysis apparatus. Organic compounds such as citric acid and sucrose were used as carbon sources. Scanning electron microscopy observation showed that they had a spherical morphology with nonaggregation. X-ray diffraction analysis revealed that the olivine phase was obtained by heating at 600 • C under argon (95%)/hydrogen (5%) atmosphere. The chemical composition of LiFePO 4 /C powders was in good agreement with that of the starting solution. Electrochemical measurement revealed that the use of citric acid was most effective in ensuring a high rechargeable capacity and cycle stability. The rechargeable capacity of the LiFePO 4 /C cathode obtained using citric acid was 155 mAh/g at a discharge rate of 1 C. Because of the good discharge capacity of the LiFePO 4 /C cathode, it exhibited excellent cycle stability after 100 cycles at each discharge rate. Moreover, this high cycle stability of the LiFePO 4 /C cathode was maintained even at 50 • C.