High-voltage composite positive electrode material and lithium ion battery containing same

Abstract

The present invention provides a high-voltage composite positive electrode material and a lithium ion battery containing the same, the positive electrode material has a core-shell structure, a lithiumzirconium phosphate fast ion conductor is used as a shell layer material, lithium cobalt oxide and a 523 ternary material are used as core materials, and a mass ratio of the lithium cobalt oxide to the 523 ternary material is (19): 1. The lithium zirconium phosphate has excellent stability and excellent lithium ion transmission performance, and is coated on the surface of a composite positive electrode material to effectively avoid direct contact with an electrolyte, so that the side reaction between a positive electrode and the electrolyte is reduced, and the lithium ion transmission rate can be increased; and a composite material formed by mechanically and physically mixing lithium cobalt oxide with specific composition and particle size and the ternary material with specific composition and particle size is used as a matrix, and then is physically mixed with a lithium zirconium phosphate solid phase to be quickly sintered on the surface of a composite positive electrode material ata low temperature to form a coating layer; finally, the high-voltage composite positive electrode material coated with the lithium zirconium phosphate fast ion conductor is obtained.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high-voltage composite positive electrode material and a lithium ion battery containing the material. Background technique [0002] Lithium-ion batteries have high energy density, high working voltage, environmental friendliness, and strong manufacturability, and are currently widely used in mobile phones, notebook computers, electric vehicles, and energy storage fields. The rapid development of lithium-ion batteries is of great significance for solving the energy crisis and improving environmental pollution. Among them, the cathode material plays a key role in the electrochemical performance, safety performance and manufacturing cost of the lithium-ion battery. It can be said that the cathode material is a key factor restricting the development of lithium-ion batteries. At present, the commonly used cathode materials for lithium-ion batteries mainly ...

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Problems solved by technology

However, the above cathode materials have some inherent disadvantages. For example, although lithium cobalt oxide is the main material of the high energy density system, it is limited by cobalt resources, the cost is high, and it is thermally stable under the high voltage system. Poor performance and safety performance, while ternary materials such as lithium iron phosphate have low compaction density and low voltage platform, so the applicable energy density system is low, and lithium iron phosphate has the disadvantage of poor low temperature performance, while lithium manganese oxide has the disadvantage of high temperature Poor cycle performance

[0003] As the demand for mobile phones and tablets in the 3C digital field is becoming lighter and thinner, the energy density requirements for lithium-ion batteries are also getting higher and higher. Lithium cobalt oxide, as the main positive electrode material with high energy density, increases its upper limit operating voltage and The gram capacity is considered to be an effective way to increase the energy density, but when the working voltage is increased, the thermal stability and safety performance of the lithium cobalt oxide cathode material will be correspondingly much worse

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