Preparation method of graphene modified high-nickel-series anode material

Abstract

The invention discloses a preparation method of a graphene modified high-nickel-series anode material. The preparation method of the graphene modified high-nickel-series anode material comprises the following steps: 1) uniformly mixing a high-nickel precursor with lithium carbonate or lithium hydroxide according to a certain molar ratio, and calcining and pulverizing the mixture in a roller kiln at an oxygen atmosphere to obtain a high-nickel primary pulverized material; 2) adding a dispersing agent, an adhesive and graphene in a solvent, and uniformly stirring and dispersing to form grapheneconductive slurry with a certain solid content, wherein the graphene conductive slurry is uniform emulsion in a dispersing state, and sedimentation and layering do not exist; 3) stirring the grapheneconductive slurry and the high-nickel primary pulverized material for a certain time according to a certain ratio, standing, filtering and drying; and 4) calcining and pulverizing the dried material in the roller kiln at a mixed gas atmosphere to obtain the final graphene modified high-nickel product. The graphene modified high-nickel anode material produced by the method has the characteristics of uniform wrapping, excellent rate capability and high-temperature cycle performance and stable process, and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of preparation of lithium-ion secondary battery electrode materials, and in particular relates to a preparation method of a graphene-modified high-nickel series cathode material. Background technique [0002] With the increasing demand for power lithium batteries in the field of new energy, the development route of power battery cathode materials is also becoming clear: Lithium iron phosphate is limited by the theoretical energy density, and the market is limited to the bus market with slowing growth rate, and the passenger car market full of potential In the automotive market, materials represented by ternary layered nickel-cobalt-manganese-lithium oxide NCM811 and nickel-cobalt-aluminum-lithium oxide NCA are referred to as high-nickel cathode materials, and ternary layered nickel-cobalt-manganese-lithium oxide NCM333, NCM523, NCM622, etc. The material referred to as the ternary material is expected to become the abs...

AI Technical Summary

Problems solved by technology

[0004] At present, the main problems still exist in the application of high-nickel materials in power batteries include: first, the lithium-ion diffusion coefficient and electronic conductivity of high-nickel materials are low, which makes the rate performance of the materials not very ideal; second, the surface of high-nickel materials is due to residual alkali High temperature leads to serious gas production in the cells prepared from it, serious safety problems, high temperature storage and cycle performance need to be improved

[0007] 1. The graphene silica ball-coated ternary material prepared by mechanical ball milling mixing method may cause the spherical particle fragmentation of the ternary material due to uneven mechanical force, resulting in a decrease in cycle performance and rate performance;

[0008] 2. Although silicon oxide in graphene silicon oxide balls alleviates the problem of graphene agglomeration, it still sacrifices a certain amount of conductive graphene, and the electrical conductivity decreases compared with pure graphene;

[0009] 3. The mechanical ball milling method cannot reduce the residual alkali content on the surface of high-nickel materials, and the battery process is difficult to manufacture;

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