Silicon-carbon negative electrode material and preparation method thereof

Abstract

The invention discloses a silicon-carbon negative electrode material and a preparation method thereof. The preparation method comprises the steps of adding a polymer monomer and a catalyst into a silicon source, and obtaining a polymer nanobelt coated silicon material under the heating and stirring conditions; and carbonizing the polymer nanobelt coated silicon material in an inert gas to obtain the silicon-carbon negative electrode material. According to the invention, formaldehyde, acetaldehyde and other low-steric-hindrance aldehyde monomers and phenolic monomers are polymerized and carbonized in the silicon source to form the silicon-carbon negative electrode material with a high-porosity network-shaped coating structure, not only the volume expansion of the silicon in the lithium intercalation and deintercalation process can be effectively buffered, the cycle life of a lithium ion battery is prolonged, but also a conductive network formed by interweaving the carbon nanofibers is not easy to break when the volume of the silicon particles is changed, the silicon particles in the conductive network can always keep the good electrical contact with a current collector, and the cycling stability of the silicon material is improved. The preparation method is simple, does not need a template or the complex processes, such as etching, etc., and has the excellent industrial prospect.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery negative electrode materials, in particular to a silicon-carbon negative electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in mobile phone and notebook batteries, power batteries and energy storage batteries due to their excellent properties such as high voltage, high energy density and long cycle life. With the thinner and lighter, multi-functional and larger screens of smartphones and laptops, it is difficult for existing lithium-ion batteries to meet the increasingly stringent requirements for batteries in consumer electronics, and new technologies are urgently needed to effectively improve the performance of lithium-ion batteries. specific energy. Lithium-ion batteries usually include four key materials such as negative electrode, separator, electrolyte, positive electrode and other auxiliary materials. Among ...

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide a silicon-carbon negative electrode material and its preparation method in view of the above-mentioned defects of the prior art, aiming at solving the problem that the lithium-ion battery negative electrode material in the prior art solves the problem of silicon intercalation and delithiation in the process of lithium intercalation and delithiation through the template method. The volume change problem in silicon is expensive, which is not conducive to mass production, and the cladding layer formed on the surface of the non-template method has fewer dense pores, which cannot effectively solve the problem of volume change in the process of intercalation and delithiation of silicon.

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