Method for preparing nickel-cobalt-manganese ternary cathode material

Abstract

A method for preparing a nickel-cobalt-manganese ternary cathode material comprises the steps of: injecting a mixed gas of carbon dioxide and oxygen in a reaction device, adding a nickel-cobalt-manganese mixed solution to control the pH of the reaction solution to be 9.5-10.5, and preparing a core of a nickel-cobalt-manganese ternary precursor at the temperature of 75-95 DEG C; regulating the reaction temperature to 45-65 DEG C, and regulating the pH of the reaction solution to 11.5-12.5 after crystallization; adding the nickel-cobalt-manganese mixed solution and a complexing agent solution tocontrol the pH of the reaction solution to be 11.5-12.5 and control the reaction temperature to be 45-65 DEG C, and preparing a housing of the nickel-cobalt-manganese ternary precursor; performing post-treatment of the product such as ageing to obtain a nickel-cobalt-manganese ternary precursor of a composite [alpha]-type and [beta]-type core-shell structure; and performing ball-milling mixing ofthe nickel-cobalt-manganese ternary precursor with lithium hydroxide to obtain a burn-in ternary cathode material through high-temperature sintering; and performing high-temperature sintering to obtain a nickel-cobalt-manganese ternary cathode material. The prepared cathode material is good in capacity, is high in capacity maintenance rate after multiple cycle and outstanding in electrochemical performance.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of a nickel-cobalt-manganese ternary positive electrode material. Background technique [0002] Generally, the ternary positive electrode material is formed by mixing secondary spherical particles formed by the agglomeration of fine grains of nickel-cobalt-manganese hydroxide and lithium hydroxide and then calcining. However, there are the following problems for high-nickel ternary positive electrode materials, especially secondary spherical particles: 1. During the sintering process of high-nickel ternary positive electrode materials, the sintering temperature is low, resulting in slow Li ion insertion speed. Secondary spherical particles, due to the dense accumulation of primary particles, it is difficult for lithium to burn into the interior of the particles, resulting in uneven lithium melting inside and outside the particles, re...

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Problems solved by technology

However, there are the following problems for high-nickel ternary positive electrode materials, especially secondary spherical particles: 1. During the sintering process of high-nickel ternary positive electrode materials, the sintering temperature is low, resulting in slow Li ion insertion speed. Secondary spherical particles, due to the dense accumulation of primary particles, it is difficult for lithium to burn into the interior of the particles, resulting in uneven lithium melting inside and outside the particles, resulting in high residual lithium and low capacity of the positive electrode material, that is, the processing performance of the ternary precursor is not good; 2. Generally, the capacity, cycle performance and safety performance of batteries using ternary cathode materials will decrease after multiple charge and discharge cycles

Cause a series of problems such as reduced battery capacity, poor cycle performance, and reduced safety performance

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