TiO2-Modified Spinel Lithium Manganate for Suppressing Mn Ion Dissolution in Lithium Ion Batteries

Capacity fading of spinel lithium manganate-based batteries is mainly caused by the dissolution of manganese, which limits their large-scale application. Suppressing the dissolution of manganese is crucial to reduce the capacity decline of lithium manganate-based batteries. Using a sol-gel method, Titanium dioxide (TiO2) was doped into the surface layer of a spinel LiMn2O4 core, X-ray diffraction data showed that the crystal structure after modification was similar to the bulk spinel LiMn2O4, indicating cationic shell LiMn2-xTixO4 was formed. The phase similarity between the pristine and doped layers fully maintained the ionic and electronic transport channels. Meanwhile, the doped surface layer blocked direct contact between LiMn2O4 and the electrolyte, preventing corrosion of LiMn2O4 in the electrolyte. Cycle performance experiments at elevated temperature and high rate fully demonstrated the excellent cyclability of the doped structure as a cathode material, and manganese dissolution test gave direct evidence for the superior effect of the modified cathode in suppressing Mn dissolution.