Negative electrode material for lithium ion secondary battery, negative electrode sheet, and lithium ion secondary battery

Abstract

The invention discloses a negative electrode material and a negative electrode sheet of a lithium ion secondary battery, and the lithium ion secondary battery. According to the preparation method, a silicon-based negative electrode active material and a graphite negative electrode active material are compounded to serve as a negative electrode active material, the silicon-based negative electrodeactive material takes a high-capacity silica material SiOx as a core, and the surface of the silicon-based negative electrode active material is coated with a carbon active substance; and meanwhile, conductive agents such as single-walled carbon nanotubes are added into the negative electrode material. Through the arrangement, the energy density of the lithium ion secondary battery can be improved, the electronic conductivity of the silicon-oxygen material is improved, the volume change of the silicon-oxygen material in battery circulation is favorably buffered, meanwhile, the first coulombicefficiency of the silicon-oxygen material is improved, and the problems of low first coulombic efficiency and poor rate capability of the silicon-oxygen material can be effectively solved.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to negative electrode materials, negative electrode sheets and lithium ion secondary batteries of lithium ion secondary batteries. Background technique [0002] Lithium-ion batteries have become ideal power sources for portable electronic devices, electric vehicles and energy storage due to their excellent cycle life, high energy density, and environmental friendliness. With the development of the above fields, the power system puts forward higher requirements on the energy density of lithium-ion batteries. [0003] The anode materials of traditional lithium-ion batteries are mainly graphite materials such as natural graphite, artificial graphite or composite graphite, and the theoretical gram capacity of graphite materials is only 372mAh / g. Although with the development of technology, the actual reversible gram capacity of graphite materials is gradually increasing, ...

AI Technical Summary

Problems solved by technology

At present, in the research on lithium supplementation technology, most of them are supplementing lithium on the negative electrode, and most of the research on lithium supplementation for silicon-based negative electrode materials is relatively complicated, such as thermal doping, electrochemical doping, lithium organic solution doping Wait

In the process of realizing the embodiment of the present application, the inventors of the present application found that the above-mentioned technology has at least the following technical problems: the process is cumbersome, the equipment cost is high, the production environment is harsh, and the uniformity is difficult to control, and the prepared lithium ion The cycle stability of secondary batteries is poor, and it is difficult to industrialize production

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