Method for preparing coated layered positive electrode material from sodium metaaluminate

Abstract

The invention discloses a method for preparing a coated layered positive electrode material from sodium metaaluminate. The method comprises 1, weighing polyvinylpyrrolidone (PVP) and a layered positive electrode material according to a mass ratio of 1: 75, dissolving the PVP in deionized water, and dispersing the layered positive electrode material in the solution to obtain a solution A, 2, weighing a complexing agent and sodium metaaluminate according to a mole ratio of 5: 100 to 30: 100, 3, dissolving the weighed sodium metaaluminate in deionized water to obtain a sodium metaaluminate solution with a concentration of 0.01-0.09mol / L, 4, dissolving the weighed complexing agent in an acid solution with a concentration of 0.01mol / L to obtain a solution C, 5, under conditions of a constant temperature water bath and vigorous stirring, simultaneously pumping the solution B and the solution C into the solution A, wherein reaction pH is kept in a range of 9-10 through control of a solution C pumping rate, 6, after the solution B is pumped into the solution A, carrying out vigorous stirring for 1h under the condition of a constant temperature water bath, and 7, carrying out pumping filtration, washing, drying and calcining on the reaction product solution to obtain the alumina membrane-coated layered positive electrode material.

Description

technical field [0001] The invention relates to the field of lithium-ion battery electrode materials, in particular to a method for preparing a layered cathode material coated with sodium metaaluminate as a raw material. Background technique [0002] Due to the advantages of small size, light weight, large capacity, small self-discharge, long cycle life, and no memory effect, lithium-ion batteries have become a hot spot for current researchers. Among them, the research of positive electrode materials is the most important thing, but layered LiCoO2 causes lattice distortion due to the dissolution of Co4+ in the later stage of charging, and the lattice shrinkage along the c-axis direction due to the loss of a large amount of Li+ and the resulting Li dislocation phenomenon make it difficult to further improve the electrochemical performance; the layered Li-rich Manganese-based cathode materials have seriously hindered the application of materials due to the large loss of the fi...

AI Technical Summary

Problems solved by technology

Summarizing these patent documents at home and abroad, we found that the coating process of most researchers is often simple and rough, which makes the coating layer too loose or incomplete. Although the capacity retention rate is improved to a certain extent, it cannot be coated or coated. The relatively weak part may react with a small amount of HF in the electrolyte during the electrochemical cycle, and part of Co will also dissolve, resulting in the inability to further improve the electrochemical performance of LiCoO2.

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