Synthesis method and application of fluorine-doped carbon-coated silica nanoparticles@carbon nanotube composites

Abstract

The invention discloses a synthesis method and application of a fluorine-doped and carbon-coated silicon oxide nanoparticles @ carbon nanotube composite material. The synthesis method is characterizedin that tetrapropoxysilane, a perfluorinated sulfonic acid resin dispersion liquid and carbon nanotubes are used as main raw materials, and mixing, high-temperature calcination, reaction and postprocessing are carried out to prepare the fluorine-doped and carbon-coated silicon oxide nanoparticles @ carbon nanotube composite material. The synthesis method disclosed by the invention has the advantages of high simplicity and easiness; fluorine-containing organics are used for fluorine doping and carbon coating of a silica-based material, and the carbon nanotubes are introduced to form a siliconoxide and carbon nanotube composite structure, so that a three-dimensional network structure of the carbon nanotubes can provide space intervals for fluorine-doped and carbon-coated silicon oxide nanoparticles, and the electrochemical performance of the composite structure can be remarkably improved through the fluorine doping and the carbon coating; and the fluorine-doped and carbon-coated silicon oxide nanoparticles @ carbon nanotube composite material prepared through the synthesis method can be used as a negative electrode material for a lithium ion hybrid capacitor to remarkably improve the cycling performance and the charge / discharge performance of the capacitor.

Description

technical field [0001] The invention relates to the technical field of lithium ion capacitors, in particular to a synthesis method and application of a fluorine-doped carbon-coated silicon oxide nanoparticle@carbon nanotube composite material. Background technique [0002] The global environmental pollution and energy crisis are becoming more and more serious, and it is imminent to develop new sustainable chemical energy storage devices. Lithium-ion hybrid capacitors are attracting attention due to their excellent performance. Lithium-ion hybrid capacitor is a new type of power energy storage device between lithium-ion batteries and electric double-layer supercapacitors. Compared with lithium-ion batteries, it has better high-rate discharge and cycle life. Compared with supercapacitors, the energy density can be increased by 3-6 times. [0003] The electrode is the core of the lithium-ion hybrid capacitor, and the electrochemical performance of the electrode determines the...

AI Technical Summary

Problems solved by technology

However, silicon itself has the problem of volume expansion and poor conductivity, which determines its short life and poor cycle performance.

[0005] At present, one of the main ways to improve the silicon negative electrode is to nanometerize silicon materials, such as nanofilms, nanowires, nanoparticles, etc., nanometerized silicon can better release the stress caused by volume changes, and at the same time provide space for volume expansion. However, due to the low intrinsic conductivity of silicon, nano-sized silicon will still have obvious capacity fading after many cycles, and the battery power density is also low.

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