To reduce high dissolution of manganese ions (Mn3+) into the electrolytes in lithium-ion batteries, causing severe capacity loss during storage and cycle, TiO2 is simply coated onto LiMn2O4 powders by the sol-gel method and investigated by various analytical techniques. Whereas the surface layer of TiO2 on LiMn2O4 powders is stable up to 600 oC, annealing at and above 700 oC induces the reaction of TiO2 surface layer with LiMn2O4 host particle. The passive TiO2 layer on LiMn2O4 annealed at 500 oC effectively suppress Mn dissolution at room temperature and even higher temperature (55 oC). Moreover, TiO2- coated LiMn2O4 annealed at 500 oC improves the cycle property at high voltage of 4.50 V charging and even at high temperature. Hence, TiO2-coated LiMn2O4 can be a promising candidate of cathode active material for lithium-ion batteries.

Keywords: LiMn2O4, TiO2, Surface modification, Mn dissolution.