Method for coating positive electrode material by using organic silicon coupling agent

Abstract

The invention discloses a method for coating a positive electrode material by using an organic silicon coupling agent, which comprises the following steps: a reaction liquid preparation step: adding deionized water and the organic silicon coupling agent into an organic solvent to prepare a reaction liquid; a mixed reaction step: placing the positive electrode material in the reaction liquid, uniformly mixing and stirring, then maintaining the temperature of the reaction liquid at 80-130 DEG C, and keeping the temperature for 1-5 hours; and a filtering and drying step: filtering out the positive electrode material from the reaction liquid, and drying the positive electrode material for 6-10 hours in an environment at the temperature of 60-120 DEG C. The invention has the following beneficial effects: after the positive electrode material prepared by the method is assembled into a battery, the high-temperature and high-pressure performance of the battery is obviously improved, and the cycle performance is also greatly improved.

Description

technical field [0001] The invention relates to the field of battery preparation, in particular to a method for coating a positive electrode material with an organic silicon coupling agent. Background technique [0002] High-nickel ternary batteries are prone to problems such as gas production on the surface of positive particles and metal dissolution at high temperatures, resulting in poor cycle performance. In order to improve this problem, the common method is to coat the surface of the positive electrode or add positive film-forming additives to the electrolyte. In the scheme shown in patent CN110429269A, a copolymer is used to coat the surface of a high-nickel ternary positive electrode material. The specific method is to use a lithium-containing olefin polymer and a conjugated olefin polymer to copolymerize, and then dissolve the polymer in a solvent. The high-nickel ternary material particles are dispersed in the solvent, and are coated on the surface by evaporating ...

AI Technical Summary

Problems solved by technology

Although this method can better isolate the positive electrode particles from the electrolyte, because the polymer is not uniformly coated on the surface of the high-nickel ternary material, the binding force is not enough, and it is easy to dissolve in the electrolyte during continuous charging and discharging. In the scheme shown in the patent CN110247031A, lithium cobalt oxide is coated on the surface of the ternary positive electrode material. Although the direct contact between the ternary material and the electrolyte can be avoided, the lithium cobalt oxide will also produce gas at high temperature, and the lithium cobalt oxide There will also be metal dissolution problems during charging and discharging.

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