Graphite negative electrode structure combination and preparation method thereof, and lithium battery cell

Abstract

The invention relates to the technical field of a lithium battery, particularly a graphite negative electrode structure combination and a preparation method thereof. The graphite negative electrode structure combination comprises a negative electrode structure and a surface modification layer formed on the negative electrode structure; the negative electrode structure comprises a negative electrode current collector and a graphite negative electrode layer formed on the negative electrode current collector; the negative electrode current collector, the graphite negative electrode layer and thesurface modification layer are arranged in an overlaid manner; the graphite negative electrode layer comprises a graphite active material; and the surface modification layer comprises a lithium compound with the ionic conduction characteristic. By taking the surface modification layer as a stable artificial SEI membrane, lithium ion damage in the charging cycle process can be well reduced, the initial charging and discharging coulombic effect is improved, and the specific capacity density of the graphite negative electrode layer is improved; and meanwhile, the surface modification layer can well block macromolecule groups from being nested into the graphite negative electrode layer along with lithium ions, so that stripping of graphite can be avoided, the structural stability of the negative electrode structure can be maintained, and stable conductive performance can be achieved.

Description

【Technical field】 [0001] The invention relates to the technical field of lithium batteries, in particular to a graphite negative electrode structure combination, a preparation method thereof, and a lithium battery cell. 【Background technique】 [0002] Since the commercialization of lithium batteries in 1990, lithium batteries have been widely used in 3C, electric vehicles and energy storage fields. As an important part of lithium batteries, negative electrode materials directly affect the specific capacity, energy density, cycle life and internal resistance of lithium batteries. At present, the active material of the commercial lithium battery negative electrode is graphite, which is mainly because the volume change of the graphite negative electrode is small during the charging and discharging process of the battery. In addition, during the charge and discharge process of the lithium battery, a solid electrolyte film (SEI film) is formed at the interface between the graphi...

AI Technical Summary

Problems solved by technology

[0003] In order to overcome the problems of low energy density and poor cycle stability of current graphite-based negative electrode lithium batteries, the present invention provides a graphite negative electrode structure combination with good cycle stability and high specific capacity density and a preparation method thereof

Images