Preparation method of coated modified lithium manganate positive electrode material

The invention discloses a preparation method of a coated modified lithium manganate positive electrode material, which comprises the following steps: 1) mechanically mixing a manganese source and a lithium source in proportion, roasting the uniformly mixed material under an atmosphere condition, and crushing and grading the sintered material to obtain the lithium manganate positive electrode material; 2) mechanically mixing a nickel salt, a cobalt salt, a manganese salt and a lithium salt according to a certain mixing proportion, adding one of water and ethanol according to a certain solid content, putting the obtained material into a pulping machine for pulping, and inputting the obtained slurry into a sand mill for sanding to obtain a mixed solution; carrying out drying granulation on the sanded slurry by adopting a spray dryer to obtain a nano single crystal lithium-rich manganese-based positive electrode material precursor; and 3) performing primary roasting on the nano single crystal lithium-rich mangane