Lithium-rich manganese-based Electrode material and preparation method thereof

Abstract

The invention relates to a preparation method of a lithium-rich manganese-based positive electrode material. The preparation method comprises the following steps of: (1) dissolving a niobium carboxylic acid derivative in deionized water to prepare a solution with the pH value of 1-3; (2) mixing a lithium-rich manganese-based material with the solution of the niobium carboxylic acid derivative formixing, and stirring and heating the mixture to a temperature of 55-80 DEG C, preferably 60-65 DEG C to form a suspension; (3) adding a lithium source, a complexing agent and a dispersing agent according to a molar ratio of 1:1-3:0.01-0.5 into the suspension, performing heating at a temperature of 60-100 DEG C for 10h to form a lithium-rich manganese-based material coated with a Li-Nb precursor; and (4) performing calcination of the lithium-rich manganese-based material coated with the Li-Nb precursor at a temperature of 500-900 DEG C for 5-15h to obtain a manganese-based positive electrode material. The method employs the mild acidity of the solution of the niobium carboxylic acid derivative to construct Li+ / H+ structure defects at the surface of the lithium-rich manganese-based material,and performs addition of the lithium source and the high-temperature solid-phase reaction to construct an Nb-doped / LiNbO3-coated dual-shell surface reconstruction layer so as to obviously improve theelectrochemical performance of the lithium-rich manganese-based material.

Description

Technical field [0001] The invention relates to a method for performing surface modification treatment on a lithium-rich manganese-based positive electrode material and an electrode prepared by the method, and belongs to the technical field of lithium batteries. Background technique [0002] Lithium-rich manganese (xLi 2 MnO 3 ·(1-x)LiMO 2 ) Discharge specific capacity can reach 250mAh·g -1 , And low cost, it is expected to become the cathode material of the next generation electric vehicle power battery. Nevertheless, its inherent shortcomings limit its application. These shortcomings include: (1) the lower Coulomb efficiency caused by the irreversible phase transition during the first cycle; (2) the transition metal ion's low coulombic efficiency when charged to a higher voltage. Dissolution; (3) Voltage attenuation during long cycle cycles; (4) Poor rate and cycle performance. In response to the above problems, researchers have proposed some solutions, including bulk doping a...

AI Technical Summary

Problems solved by technology

However, its inherent disadvantages limit its application, including: (1) low Coulombic efficiency due to irreversible phase transition during the first cycle; Dissolution; (3) Voltage decay during long-term cycling; (4) Poor rate and cycle performance, etc.

Images