Silicon-carbon composite nano-tube preparation method

Abstract

The present invention discloses a silicon-carbon composite nano-tube preparation method, which comprises: dissolving zinc oxide nano-rods in a solvent, adjusting to achieve an alkaline state, mixing with tetraethyl orthosilicate, reacting, carrying out centrifugation drying to obtain a silicon dioxide coated core-shell structure material, recording as ZnO@SiO2, adding the ZnO@SiO2 to a reactor, heating in the presence of an inert gas, introducing acetylene gas, reacting, depositing a carbon coating layer on the silicon dioxide coated core-shell structure material surface, recording as ZnO@SiO2@C, carrying out a magnesium thermal reduction reaction on the ZnO@SiO2@C, removing the zinc oxide nano-rod template, and carrying out a post-treatment to obtain the silicon-carbon composite nano-tubes. According to the present invention, the zinc oxide nano-rods are adopted as the template to prepare the silicon-carbon composite nano-tubes, the preparation process is simple, the template removing is convenient and complete, the large-scale industrial production is easily achieved, and the new approach for synthesizing other types of the nano-tubes is provided.

Description

technical field [0001] The invention relates to the technical field of material preparation, in particular to a method for preparing silicon-carbon composite nanotubes. Background technique [0002] Silicon material is the current research hotspot of lithium-ion battery anode materials, and has the highest specific capacity (4200mAh / g) in theory. However, the lithium-silicon alloy formed during the lithium intercalation and deintercalation process has a huge volume expansion change, which leads to powdering, crushing and final shedding of the electrode material, and a sharp decline in the cycle performance of the material. In order to solve the problem of silicon volume expansion, researchers have studied a variety of methods to improve, and there are three typical methods: [0003] 1. Preparation of nanoscale silicon materials, such as silicon nanoparticles, silicon nanofilms, etc.; [0004] 2. Prepare silicon materials with void structures, such as porous silicon, silico...

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Problems solved by technology

[0009] The silicon nanotubes prepared by this method are coated on the outside of the carbon tubes, which is not conducive to the carbon material to suppress the stress generated by the outward expansion of silicon during the lithium intercalation process, and the length of the silicon nanotubes is too long, which is not conducive to maintaining the tubular structure and Improve the transport efficiency of lithium ions in the material; and the anodic aluminum oxide template (AAO) is not easy to remove, the multiple CVD method requires harsh conditions, high cost, and less output at one time

[0010] At present, there are still some difficulties in the preparation of silicon nanotubes, mainly because the preparation method is complicated, the synthesis is difficult, the cost is high and the yield is low, catalysts or high-cost sputtering methods are often used, and template removal is difficult. Inevitably complicate the process and increase the cost

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