Graphite material with long cycle characteristic for lithium battery and preparation method thereof

Abstract

The invention discloses a graphite material with a long cycle characteristic for a lithium battery. The graphite material comprises 90-110 parts of a graphite main body material, 10-50 parts of an enhancer material, 5-10 parts of an adhesive, 1-5 parts of a surfactant and 1-500 parts of water, and the enhancer material comprises a carbonized material and a carbon fluoride material in a mass ratio of 0.05-0.5: 1. The invention also provides a preparation method which comprises the following steps: (1) putting the carbonized material and the carbon fluoride material into a shearing mixer for dry mixing to obtain a mixed powder material; (2) adding 30%-50% of the adhesive for mixing to obtain an enhancer mixture; (3) adding a graphite main body material for mixing to obtain a coarse material; (4) adding the surfactant and water, stirring till that the viscosity reaches a standard, adding the residual adhesive, and uniformly mixing to obtain a graphite negative electrode slurry; and (5) coating a copper foil with the graphite negative electrode slurry, then performing drying in a vacuum drying oven, and performing rolling in a rolling device to obtain the graphite material negative electrode plate for the lithium battery. The electrochemical performance of the battery can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of graphite material preparation, and in particular relates to a graphite material for lithium batteries with long cycle characteristics, and a preparation method thereof. Background technique [0002] A lithium-ion battery mainly includes a positive electrode, a negative electrode, an electrolyte that can conduct lithium ions, and a separator that separates the positive and negative electrodes. Among them, lithium-ion battery negative electrode materials are divided into the following categories: carbon material negative electrodes (including graphite carbon materials, non-graphite carbon materials, doped carbon materials, coated carbon materials), non-carbon negative electrodes (including alloy negative electrodes and transition metal oxide anode). In recent years, lithium-ion batteries have been widely used in various portable electronic devices, and gradually applied to emerging fields such as electric ...

AI Technical Summary

Problems solved by technology

However, for high-power graphite anode materials, due to the low tap density of the material itself, relatively large specific surface area, and more functional groups, when the direct wet mixing process is used, it will cause the components in the slurry to be difficult to obtain. Uniform mixing, even agglomeration and stratification. In addition, the long-term dispersion process can easily lead to side reactions between the functional groups on the graphite and other substances, and ultimately it is impossible to obtain a uniform and stable negative electrode slurry

At the same time, when the negative electrode slurry is further processed into negative electrode sheets, due to the low accuracy of the equipment, the coated negative electrode slurry is uneven and the loss rate is high, which eventually leads to uneven quality of lithium batteries

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