Graphite negative electrode material for lithium ion battery and preparation method of graphite negative electrode material

Abstract

The invention provides a graphite negative electrode material for a lithium ion battery. The graphite negative electrode material uses a graphite material as an inner core, a conductive network membrane consisting of lignin pyrolytic carbon and graphene coats the surface of the graphite material, and the weight of the conductive network membrane is 0.03-8 percent of the weight of the graphite negative electrode material. The negative electrode material is prepared by adopting the following steps: (1), uniformly mixing graphite powder, lignin and oxidized graphene in a dispersing medium; and (2), drying a prepared mixture, then placing the dried mixture in a sintering furnace, roasting in an inert atmosphere or reducing mixture atmosphere at the constant temperature of 350-600 DEG C for 3-10 h, then roasting at constant temperature of 650-1200 DEG C for 5-20 h, and then cooling to room temperature. According to the graphite negative electrode material, the electric conductivity of the graphite negative electrode material is remarkably increased, and thus the high magnification performance and the cycle performance of the graphite negative electrode material for the lithium ion battery are improved, and the irreversible capacity of the graphite negative electrode material for the lithium ion battery is reduced.

Description

technical field [0001] The invention relates to a negative electrode material for a lithium ion battery and a preparation method thereof, in particular to a graphite negative electrode material whose surface is coated with carbonized lignin and graphene and a preparation method thereof. Background technique [0002] With the development of miniaturization and mobility of electronic products, and the rapid development of power batteries for electric tools, electric motorcycles and electric vehicles, high-power and high-capacity lithium-ion batteries have become a hot spot in the development of countries all over the world. As the anode material, one of the four main materials of lithium-ion batteries, the anode material that has been commercialized and used with the best effect is graphite carbon material, mainly including artificial graphite and natural graphite. [0003] Artificial graphite includes artificial graphite powder, mesocarbon microspheres and mesocarbon fibers. ...

AI Technical Summary

Problems solved by technology

Although there are many patents and literature reports on the surface coating modification of graphite anode materials by graphene oxide or graphene to improve the high rate performance, cycle performance and reversible capacity of graphite anode materials, but the performance of graphite anode materials The improvement, especially the improvement of high-current charge and discharge performance is not very significant, so that the application of graphite anode materials in high-end lithium-ion batteries is limited to a certain extent

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