Modified lithium manganate positive electrode material and preparation method thereof

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a modified lithium manganate positive electrode material and a preparation method thereof. The invention provides a modified lithium manganate positive electrode material. The modified lithium manganate positive electrode material comprises lithium manganate and a lithium lanthanum titanium oxide solid electrolyte coating the surface of the lithium manganate, the chemical composition of the lithium lanthanum titanium oxide solid electrolyte is Li < 1-x > LaxTiO3, wherein x is more than or equal to 0.1 and less than or equal to 0.8. The surface of the lithium manganate positive electrode material is coated with the lithium lanthanum titanium oxide solid electrolyte, so that direct contact between the lithium manganate positive electrode material and the electrolyte can be avoided, the lithium ion migration rate of the surface of the material can be improved, and the rate capability of the material is improved; an