Carbon-silicon composite material with spherical nucleocapsid, and its preparing method and use

Abstract

This invention relates to a kind of silicon&carbon composite material with a spherical appearance and core-shell structure in spherical particles with a mean diameter of 1.2~53 micron and a 'core-shell' structure, there are silicon particles 5~50wt% and carbon particles 50~95wt%, the core of which is spherical carbon particles with a mean diameter of 1~45 micron. The carbon particles are the mixture of one, two or three kinds of mesophase carbon graphite balls, hard carbon balls and spherical graphite ball. The thickness of the shell is 0.1~4 microns composed of carbon and silicon grains with the average size of 10 nm~4 micron. The carbon&silicon composite materials are achieved through thermal decomposition and chemical vapor deposition after the spherical carbon particles are coated with silicon and carbon composite ultrafine silica slurry.

Description

technical field

[0001] The invention relates to a carbon-silicon composite material, in particular to a carbon-silicon composite material with a spherical appearance and a core-shell structure, its preparation method and application. Background technique

[0002] Since Japan's SONY company applied for the use of carbon as the negative electrode active material in 1989, LiCoO 2 The patent of the secondary lithium battery used as the positive electrode active material, and after it was first commercialized in 1992, the secondary lithium battery began to develop rapidly. Various forms of carbon materials such as petroleum coke, carbon fiber, pyrolytic carbon, natural graphite, and artificial graphite are widely selected as negative electrode active materials for secondary lithium batteries. However, the theoretical specific capacity of carbon as the negative electrode active material is 372mAh / g. It cannot satisfy people's further pursuit of high energy density secondary batt...

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