Lithium cobaltate-coated high-nickel ternary positive electrode material and preparation method thereof

Abstract

The invention relates to a lithium cobaltate-coated high-nickel ternary positive electrode material and a preparation method thereof. The preparation method comprises the following steps of: mixing a high-nickel ternary precursor, nano cobaltosic oxide, and a lithium source, and calcining the mixture at 750-820 degrees centigrade to obtain the lithium cobaltate-coated high-nickel ternary positive electrode material, wherein the mass ratio of the nano cobaltosic oxide to the high-nickel ternary precursor is 0.05 to 0.2:1. The surface of the high-nickel ternary positive electrode material is uniformly coated with a layer of lithium cobaltate material, thereby protecting the reticular structure of the high-nickel ternary positive electrode material, reducing the nickel-lithium ion mixing, improving the electronic conduction, the cycle performance and the rate performance of the material, additionally avoiding direct contact between the surface of high-nickel ternary positive electrode material and the air, reducing the water absorption of the material and the formation of surface lithium hydroxide and lithium carbonate, reducing residual alkali on the surface of the material, and optimizing the processing properties of the material.

Description

Technical field [0001] The invention belongs to the technical field of battery materials, and specifically relates to a lithium cobalt oxide coated high nickel ternary positive electrode material and a preparation method thereof. Background technique [0002] Nowadays, there are more coating processes in which two different cathode materials are coated with each other to obtain a composite material with the respective properties of the two materials; the mutual coating materials used include lithium iron lithium oxide and titanium phosphate Lithium, lithium manganate, lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, etc.; this kind of coating methods are also different, some simply mix and coat the two finished materials, and some In the preparation process, it is mixed and coated and then sintered. In this type of coating process, the excellent properties of the two materials can be combined to a certain extent, but some properties ar...

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Problems solved by technology

[0002] In the current coating process, two different positive electrode materials are often coated with each other to obtain a composite material with the respective properties of the two materials; the mutual coating materials used include lithium iron lithium oxide, titanium phosphate Lithium, lithium manganese oxide, lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, etc.; the coating methods of this type are also different, some simply mix the two finished materials for coating, and some In the preparation process, after mixing and coating, sintering, etc.; in this type of coating process, the excellent properties of the two materials can be combined to a certain extent, but some of them have improved some properties but reduced others. Performance, Chinese Invention Patent Application Publication No. CN 108777291 A discloses a preparation method of lithium manganate-coated high-nickel ternary lithium battery positive electrode material, due to the mixed ball milling of strong oxidizing anhydride and precursor, the precursor powder It is pre-oxidized to NCMOOH, thereby reducing the mixed discharge of nickel and lithium, improving the reversible capacity of the battery, and at the same time eluting the residual alkali on the surface through its strong water absorption and weak acidity, so that the content of lithium carbonate on the surface of the positive electrode material is reduced. gas generation, thereby increasing its stability

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