Syntheses of Mn3O4 and LiMn2O4 nanoparticles by a simple sonochemical method

Abstract Mn 3 O 4 and LiMn 2 O 4 nanoparticles were prepared by a simple sonochemical method which is environmentally benign. First, Mn 3 O 4 nanoparticles were prepared by reacting MnCl 2 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 Mn 3 O 4 under the same sonochemical conditions as above. The thickness of coated LiOH on Mn 3 O 4 obtained from the reaction ratio of 3:1 between LiOH and Mn 3 O 4 was about 4.5–5.5 nm range. Then, by heating those LiOH-coated Mn 3 O 4 particles at the relatively low temperature of 300–500 °C for 1 h, they were transformed into phase-pure LiMn 2 O 4 nanoparticles of about 50 to 70 nm size in diameter.