Syntheses of Mn3O4 and LiMn2O4 nanoparticles by a simple sonochemical method

Mn3O4 and LiMn2O4 nanoparticles were prepared by a simple sonochemical method which is environmentally benign. First, Mn3O4 nanoparticles were prepared by reacting MnCl2 and NaOH in water at room temperature through a sonochemical method, operated at 20 kHz and 220 W for 20 min. Second, LiOH was coated onto the resulting Mn3O4 under the same sonochemical conditions as above. The thickness of coated LiOH on Mn3O4 obtained from the reaction ratio of 3:1 between LiOH and Mn3O4 was about 4.5–5.5 nm range. Then, by heating those LiOH-coated Mn3O4 particles at the relatively low temperature of 300–500 °C for 1 h, they were transformed into phase-pure LiMn2O4 nanoparticles of about 50 to 70 nm size in diameter.