Method for preparing carbon-carbon composite lithium ion battery cathode material

Abstract

The invention discloses a method for preparing a carbon-carbon composite lithium ion battery cathode material, and relates to the field of lithium batteries. The method comprises the following steps of: (1) preparing spherical graphite; (2) preparing a coating material: fully mixing, melting and stirring an organic soft carbon material and an organic hard carbon material to form paste, and crushing the paste into particles to obtain the coating material; (3) coating the spherical graphite: stirring and mixing the spherical graphite and the coating material so that the coating material is attached to the spherical graphite to form a coating material layer; (4) forming a coating: heating the coating material layer to volatilize organic components of the coating material layer, and forming acomplete coating based on the coating material layer so as to obtain a semi-finished material; and (5) treating the semi-finished material at a high temperature: treating the semi-finished material at the high temperature, and forming a netlike structure and a plurality of nano pores or nano channels or nano cracks on the surface of the coating so as to obtain a finished material. Because a net rack structure is formed on the surface of the lithium ion battery cathode material, the strength is enhanced; and meanwhile, the nano pores or the nano channels or the like are formed in the coating, so the capacity ratio of the material is increased.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of a carbon-carbon composite lithium ion battery negative electrode material. Background technique [0002] With the continuous development of electronic technology, especially the application and popularization of portable electronic devices and electric vehicles, the demand for lithium-ion batteries with high specific energy and long cycle life has also greatly increased. The lithium-ion battery anode material is its key technology, and its quality directly determines the quality of the lithium battery. Existing lithium-ion batteries generally use graphite as the negative electrode material, and it is generally in the shape of scales. The disadvantage of using scaly graphite as the negative electrode material of lithium-ion batteries is that the graphite layers are combined with weaker intermolecular forces, namely Van der Waals forces. When ...

AI Technical Summary

Problems solved by technology

Existing lithium-ion batteries generally use graphite as the negative electrode material, and it is generally in the shape of scales. The disadvantage of using scaly graphite as the negative electrode material of lithium-ion batteries is that the graphite layers are combined with weaker intermolecular forces, namely Van der Waals forces. When charging, with the intercalation of solvated lithium ions, the layers will peel off and form a new surface, and the organic electrolyte will be continuously reduced and decomposed on the newly formed surface to form a new SEI film, which consumes a large amount of lithium. ions, which increases the first irreversible capacity loss, and at the same time, the intercalation and extraction of solvated lithium ions will cause the volume expansion and contraction of graphite particles, resulting in the partial interruption of the electrical circuit between particles, so the cycle performance is very poor

At present, the means to overcome the above material defects is usually achieved by shaping the shape of the flake graphite and pyrolytic coating the surface. Although the material properties have been improved to a certain extent, the above defects still exist. Greatly limit the application range of lithium-ion batteries