Electrochemical STM observation of LiMn2O4 thin films prepared by pulsed laser deposition

Spinel LiMn2O4 thin films were prepared by pulsed laser deposition. The surface morphology change of the film with potential cycling between 3.5 and 4.25 V was observed in 1 M LiClO4/PC by electrochemical scanning tunneling microscopy. After cycling, small round-shaped particles of 120–250 nm in diameter appeared on the surface. The number of the newly formed particles increased with repeated cycling while the size decreased. The observed morphology change suggested that the small particle were formed from the solution through a kind of dissolution/precipitation reactions.