Coating method of nickel cobalt lithium manganate positive electrode material

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a coating method of a nickel cobalt lithium manganate positive electrode material. A screen coated with metal salt gel is used for carrying out coating treatment on nickel cobalt lithium manganate positive electrode material particles, the metal salt gel forms a thin film in meshes of the screen, the coating treatment is that the nickel cobalt lithium manganate positive electrode material particles make contact with the thin film in the falling process, and the thin film is stretched and completely wraps the nickel cobalt lithium manganate positive electrode material particles. The nickel cobalt lithium manganate positive electrode material particles fall off; and forming a coating layer on the surface of the nickel cobalt lithium manganate positive electrode material particle. The defect that a uniform coating layer cannot be formed by dry physical coating is avoided, a uniform and compact'protective layer 'is formed on the surface of the nickel cobalt lithium manganate positive electrode material, and the cycle performance of a corresponding battery cell is effectively improved.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for coating a positive electrode material of nickel cobalt manganate lithium. Background technique [0002] Nickel cobalt lithium manganate cathode material is widely used in power lithium batteries because of its high energy density, long cycle life and high voltage platform. The cathode material accounts for about 40% of the cost of a single cell, and its performance is directly related to the cell and The energy density, safety, lifespan of the system, etc., surface coating is the main way to modify the nickel-cobalt lithium manganate cathode material. A uniform and dense coating layer can greatly improve the comprehensive performance of nickel-cobalt lithium manganate. At present, the main coating method There are wet method, dry method, atomic deposition ALD, chemical deposition CVD, etc. Among them, the coating method of dry mixing + heat treatment wi...

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Problems solved by technology

[0002] Nickel-cobalt lithium manganese oxide cathode material is widely used in power lithium batteries because of its high energy density, long cycle life, and high voltage platform. The cathode material accounts for about 40% of the cost of a single cell, and its performance is directly related to the cell and The energy density, safety, and life of the system, etc. Surface coating is the main way to modify the cathode material of nickel-cobalt lithium manganese oxide. A uniform and dense coating layer can greatly improve the comprehensive performance of nickel-cobalt lithium manganese oxide. At present, the main coating method There are wet method, dry method, atomic deposition ALD, chemical deposition CVD, etc. Among them, the coating method of dry mixing + heat treatment with simple process and low cost is widely used. Although the dry coating process is simple in process and easy to industrialize, However, a uniform and continuous coating layer cannot be formed, and its effect of suppressing side reactions is not good. Under conditions such as high voltage and high temperature, it will inevitably lead to increased cycle attenuation or even diving of the battery; the main defects of the wet process are as follows: the nickel-cobalt-manganese cathode material particles are placed In water and other solvents, and stirred for a certain period of time, the solvent will cause damage to the surface of the positive electrode material of the lithium battery and have environmental protection problems. At the same time, the processing cost will be increased, and the production efficiency is far lower than that of the dry process.

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