Silicon carbon anode material and preparation method thereof

Abstract

The invention discloses a silicon carbon anode material and a preparation method thereof. The silicon carbon anode material in the invention comprises covalent organic frameworks, a silicon nanomaterial and a carbon nanomaterial; the covalent organic frameworks have hole channels; the silicon nanomaterial is dispersed in the hole channels; and the carbon nanomaterial is dispersed in the covalent organic frameworks and the silicon nanomaterial. The preparation method of the silicon carbon anode material in the invention comprises the steps of: S1, mixing the covalent organic frameworks with thesilicon nanomaterial, so that a mixture is obtained; and S2, adding the mixture into slurry of the carbon nanomaterial; filtering after stirring for 20-50 min, and drying filtrates at 60-100 DEG C for 1-3 h. The silicon nanomaterial is limited in the hole channel by the silicon carbon anode material; the expansion of silicon is inhibited; and the problems of serious pulverization, low cycle lifeand the like due to the fact that the silicon expansion rate is large can be solved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a silicon-carbon negative electrode material and a preparation method thereof. Background technique [0002] With the development of lithium-ion battery technology, the energy density of lithium-ion batteries is gradually increasing, and high-energy-density batteries require greater capacity for the negative electrode. [0003] At present, the development of theoretical capacity of graphite is close to the limit, and silicon anode has become an ideal anode material for high energy density batteries due to its advantages of high theoretical specific capacity, abundant reserves, and low lithium intercalation potential. [0004] However, the volume change of silicon is relatively large during the intercalation and extraction of lithium ions, and the excessive volume expansion rate can easily cause the pulverization of the electrode, which makes the battery capacity rap...

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Problems solved by technology

[0004] However, the volume change of silicon in the process of intercalation and extraction of lithium ions is relatively large, and the excessive volume expansion rate easily causes the pulverization of the electrode, which makes the battery capacity rapidly decay, and seriously reduces the cycle life of lithium-ion batteries.

[0005] At present, carbon coating is often used to limit the volume expansion of silicon anodes, but this method has limited inhibition on the volume expansion of silicon nanoparticles, and the problem of pulverization of silicon-carbon anodes has not been significantly improved, making it suitable for lithium batteries with high energy density. Applications of ion batteries are limited

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