SiO2-coated ternary positive electrode material and preparation method thereof

Abstract

The invention relates to a preparation method of a SiO2-coated ternary positive electrode material. The method comprises the following steps of S1, uniformly mixing a ternary positive electrode material with polysiloxane I or polysiloxane II to obtain a mixture A; S2, uniformly mixing a catalyst with the polysiloxane II or polysiloxane I to obtain a mixture B; S3, uniformly mixing the mixture A and the mixture B to obtain a mixture C containing polysiloxane I and polysiloxane II at the same time, and heating the mixture C to obtain an organosilicon-coated ternary positive electrode material; S4, calcining the organic silicon coated ternary positive electrode material in an oxygen-containing atmosphere to obtain the SiO2 coated ternary positive electrode material, wherein the polysiloxane Iis polysiloxane containing at least two silicon-hydrogen bonds, and the polysiloxane II is polysiloxane containing at least two alkenyl groups.

Description

technical field [0001] The invention relates to the technical field of cathode materials for lithium ion batteries, in particular to SiO 2 Covered ternary cathode material and preparation method thereof. Background technique [0002] With the increasingly prominent problems of energy crisis and environmental pollution, the development of new sustainable energy sources has attracted widespread attention. As a new high-energy green battery, lithium-ion batteries are widely used in portable electronic products, electric vehicles, and large-scale energy storage. However, with the gradual increase in energy density requirements in practical applications, people are committed to researching higher-performance cathode materials. Among them, the layered LiMO 2 (M=Ni, Co, Mn) cathode materials have high theoretical capacity (278mA h g -1 ), safety and relatively low cost have become the hotspots of current research. However, at potentials higher than 4.3 V, the cycling stability...

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Problems solved by technology

The current conventional coated SiO 2 The method is to use nano-SiO 2 Dry ball milling with positive electrode materials, but this method has the problem of uneven coating and easy falling off

And existing report patent CN109659511A and CN109473671A adopt the method of wet coating, can solve the above-mentioned problem, but they have adopted water or ethanol as dispersant, after ternary cathode material contacts with water or ethanol, can cause the Li on the surface + Dissolving in water destroys the ratio of transition metals to Li, resulting in loss of capacity and poor cycle performance

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