A single-walled carbon nanotube-silicon-carbon composite material and its preparation method and application

Abstract

The invention provides a single-walled carbon nanotube-silicon-carbon composite material and its preparation method and application, belonging to the technical field of electrode materials. The preparation method of the single-wall carbon nanotube-silicon-carbon composite material provided by the present invention includes the following steps: mixing high-crystalline silicon, a binder and a dispersant, and coating the obtained first mixed material solution on the surface of the silicon-carbon material , after drying, perform the first heat treatment to obtain a silicon-silicon-carbon material; mix soluble iron salt, ammonium molybdate, citric acid and water, and coat the second mixture solution on the surface of the silicon-silicon-carbon material, after drying Carry out the second heat treatment, obtain single-walled carbon nanotube-silicon carbon composite material; Described second heat treatment is in CH 4 and H 2 in a mixed atmosphere. The invention directly grows the single-wall carbon nanotube on the silicon-carbon material, has simple operation and low energy consumption, and the single-wall carbon nanotube in the obtained composite material is evenly distributed on the silicon-carbon material, and the composite material has excellent electrical conductivity.

Description

technical field [0001] The invention relates to the technical field of electrode materials, in particular to a single-walled carbon nanotube-silicon carbon composite material and a preparation method and application thereof. Background technique [0002] At present, most of the negative electrode materials of common lithium-ion batteries on the market are graphite (including natural graphite and artificial graphite). It is around 0.5V, and graphite also has poor high rate charge and discharge performance. Therefore, simply using graphite as the negative electrode material of lithium-ion batteries is far from meeting the needs of future high-capacity batteries. When silicon is used as the negative electrode material of lithium-ion batteries, the mass specific capacity can reach 4200mAh / g, and its volume specific capacity can reach 7200mAh / g, and the cost of silicon itself is still very low. However, the conductivity of crystalline silicon is between that of a conductor and ...

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Problems solved by technology

The conventional method of introducing single-walled carbon nanotubes is to add single-walled carbon nanotubes during the forming process of silicon carbon anode, but this method is difficult to achieve uniform distribution of single-walled carbon nanotubes, and the operation process is cumbersome and energy-consuming

For example, patent CN 109301215 A discloses a method for preparing a carbon nanotube composite porous silicon negative electrode material for lithium-ion batteries, wherein the single-walled carbon nanotubes are directly doped in nano-silicon, graphite and carbon source by ball milling, and then through subsequent steps In the preparation of silicon-carbon negative electrodes, it is difficult to mix single-walled carbon nanotubes with nano-silicon, graphite and other substances microscopically during the ball milling process, which will still affect the conduction of lithium ions and electrons, and the process is complicated, which is not conducive to industrialization

Patent CN 104617261 A discloses a method for preparing a silicon-carbon nanotube composite negative electrode material for lithium-ion batteries. Although uniformly distributed single-walled carbon nanotubes can be prepared, the preparation method requires high-pressure conditions and high energy consumption

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