Lithium niobate coated lithium-rich manganese-based positive electrode material and preparation method thereof

The invention relates to the technical field of lithium ion batteries, in particular to a lithium niobate coated lithium-rich manganese-based positive electrode material and a preparation method thereof. The preparation method comprises the following steps: preparing a mixed salt solution from a lithium salt, a manganese salt, a cobalt salt and a nickel salt, and adding a complexing agent to obtain a lithium-rich manganese-based precursor solution; lithium-rich manganese-based precursor powder is obtained through a spray drying method, and the lithium-rich manganese-based material is obtained after calcination; and depositing a lithium niobate film by taking lithium tert-butoxide and niobium ethoxide as precursor reactants by adopting an atomic layer deposition technology to obtain the lithium-rich manganese-based positive electrode material coated with lithium niobate. According to the invention, the uniform, compact and few-defect amorphous lithium niobate coating layer deposited at atomic level is realized