Boron-containing molecule modified lithium nickel cobalt manganese oxide positive material and preparation method thereof

Abstract

The invention discloses a boron-containing molecule modified lithium nickel cobalt manganese oxide positive material and a preparation method thereof. A 4-vinylphenylboronic acid layer can linked on the surface of a lithium nickel cobalt manganese oxide positive material through a covalent bond manner; and a monolayer of a boron-containing group molecular layer can be formed on the surface of a lithium nickel cobalt manganese oxide powder, which has no influence on the particle size of the material. The preparation method is convenient in operation and implement, low in required modification temperature and short in time consumption during preparation, and suitable for industrial production; The prepared positive material can have obvious enhancement by applying electrochemical cycle performance of a prepared lithium ion battery, and capacity retention rates and rate performance can be obviously improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a boron-containing molecularly modified nickel-cobalt lithium manganese oxide positive electrode material and a preparation method thereof. Background technique [0002] With the increasing demand for high-capacity and high-power-density Li-ion batteries, materials with high specific capacity have aroused great interest and received increasing attention in recent years. Especially high-nickel LiNi with low cost, low toxicity and high reversible capacity 1-x-y co x mn y o 2 Cathode material (abbreviated as NCM) is considered to be the best substitute for lithium cobalt oxide, the cathode material of traditional lithium-ion batteries. [0003] High Nickel LiNi 1-x-y co x mn y o 2 The material originates from LiNiO 2 , capable of utilizing 80% of the reversible lithium deintercalation in the matrix structure, and its capacity is as high as 220mAh g -1 , relative to hav...

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Problems solved by technology

[0004] However, the shortcomings of rapid capacity fading, increased resistance during storage and cycling, and insufficient thermal stability have seriously hindered the commercial application of this material. Highly active Ni on the surface of the material 4+ Can accelerate the decomposition of the electrolyte, resulting in electrolyte consumption and the formation of a thick solid electrolyte membrane (SEI membrane)

Another thorny problem hindering the practical application of NCM is that NCM materials are quite sensitive to moisture, which leads to the formation of LiOH on the material surface, LiOH and CO in the environment 2 Further reaction produces insulating LiCO 3 , creating an insulating layer on the surface of the material

However, expensive instruments and cumbersome operating procedures hinder the large-scale application of this technology.

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