Among three promising candidates for the cathode materials of lithium-ion batteries (LiCoO2, LiNiO2, and LiMn2O4), the spinel LiMn2O4 has economical and environmental advantages as compared to the layered compounds (LiCoO2 and LiNiO2). However, the capacity fading on long-term cycling at elevated temperatures limits the application of spinel LiMn2O4 in commercial lithium-ion batteries. To improve the cycle performance of the spinel LiMn2O4, many researchers have investigated the partially substituted lithium manganese oxides(LiMxMn2-xO4), which the manganese atom was partially replaced by some transition metals such as Co, Cr, Al or Mg. In present work, we have prepared the LiMxMn2-xO4 (x=0.1and 0.2; M=Al and Co) nanoparticles by ultrasonic spray pyrolysis method with addition of citric acid. The LiMn2O4 and LiMxMn2-xO4 (x=0.1 and 0.2; M=Al and Co) nanoparticles have been successfully synthesized from the precursor solution; LiNO3 and Mn(NO3)2-6H2O, and Al(NO3)3¥9H2O, or Co(NO3)2¥6H2O were stoichiometrically dissolved into distilled water and besides, citric acid has been added into the solution. The effect of addition of citric acid into the precursor solution on the morphology and particle size of as-preparesd LiMxMn2-xO4 was examined by X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) surface area method, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). All the samples exhibited a pure cubic spinel structure without any impurities in the XRD patterns. Nanoporous LiMxMn2-xO4 hollow particles were formed with the aggregation of LiMxMn2-xO4 naoparticles, as shown in the following figure. The as-prepared samples were used as cathode active material of lithium batteries, and then the evaluation of battery performance was carried out in various charge- discharge rates at room temperature condition.