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). The LiMxMn2-xO4 (x = 0.1 and 0.2; M = Al and Co) nanoparticles were prepared 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 were synthesized from the precursor solution. The as-prepared samples were used as cathode active material of lithium batteries, and the evaluation of battery performance was conducted in various charge-discharge rates at room temperature condition. This is an abstract of a paper presented at the AIChE Annual Meeting (Salt Lake, UT 11/4-9/2007).