Lithium-rich Manganese-based Electrode Material and Preparation Method

A preparation method of a lithium-rich manganese-based positive electrode material, including the following steps of: (1) dissolving a carboxylic acid derivative of niobium in deionized water to prepare a solution with a pH value of 1~3; (2) mixing a lithium-rich manganese-based material with the solution of the carboxylic acid derivative of niobium, and stirring and heating the mixture to a temperature of 55-80°C, preferably 60-65°C, to form a suspension; (3) adding a lithium source, a complexing agent and a dispersant into the suspension according to a molar ratio of 1:1-3:0.01-0.5, performing heating at a temperature of 60-100°C for 2-1 Oh to form a lithium-rich manganese-based material coated with a Li-Nb precursor; and (4) calcinating the lithium-rich manganese-based material, which is obtained in Step (3) and coated with Li-Nb precursor, at a temperature of 500-900°C for 5-15h to obtain a manganese-based positive electrode material. By using the mild acidity of the solution of the carboxylic acid derivative of niobium, this method constructs Li+/H+ structure defects at the surface of the lithium-rich manganese-based material, and constructs an "Nb-doped/LiNbO3-coated" dual-shell surface reconstruction layer via the addition of the lithium source and the high-temperature solid-phase reaction, thereby significantly improving the electrochemical performance of the lithium-rich manganese-based material.