A kind of graphene-coated carbon nanofiber/sulfur composite material and preparation method thereof

A technology coated with carbon nanofibers and graphene, applied to structural parts, electrical components, battery electrodes, etc., can solve the problems of reduced battery rate performance, increased contact resistance, etc., to improve electrical conductivity, inhibit dissolution, and improve cycle performance effect

Inactive Publication Date: 2020-07-17
HUNAN GUOSHENG GRAPHITE TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the sulfur distributed on the surface of carbon nanofibers increases the contact resistance of the carbon nanofiber / sulfur composite surface on the one hand, resulting in a decrease in the battery rate performance; on the other hand, it is difficult to completely inhibit the sulfur Loss of active substances and reduction products produced during sulfur discharge

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] This embodiment provides a method for preparing a graphene-coated carbon nanofiber / sulfur composite material, and the specific steps are as follows:

[0030] S1. Mix carbon nanofibers and starch uniformly at a ratio of 1:4, then add them into deionized water, and perform ultrasonic dispersion for 1 hour to obtain a uniformly mixed solution. The viscosity of the mixed solution is suitable for electrospinning;

[0031] S2. Prepare carbon microspheres from the mixed solution obtained in step S1 using electrospinning technology, wherein the specific steps of the electrospinning technology are: first put the mixed solution into a syringe, the inner diameter of the nozzle of the syringe is 3mm, and fix the syringe On the support, the nozzle is aimed at the circular receiving plate, the distance between the nozzle and the circular receiving plate is 15cm, and the circular receiving plate rotates at a speed of 15r / min, and the spinning is carried out under the DC high voltage, w...

Embodiment 2

[0036] This embodiment provides a method for preparing a graphene-coated carbon nanofiber / sulfur composite material, and the specific steps are as follows:

[0037] S1. Mix carbon nanofibers and starch uniformly at a ratio of 1:5, then add them into deionized water, and perform ultrasonic dispersion for 3 hours to obtain a uniform mixed solution. The viscosity of the mixed solution is suitable for electrospinning;

[0038] S2. Using the electrospinning technology to prepare the mixed solution obtained in step S1 to obtain carbon microspheres, wherein the specific steps of the electrospinning technology are: first put the mixed solution into a syringe, and the inner diameter of the nozzle of the syringe is 4 mm, and fix the syringe On the support, the nozzle is aimed at the circular receiving plate, the distance between the nozzle and the circular receiving plate is 20cm, and the circular receiving plate rotates at a speed of 20r / min, and the spinning is carried out under the DC...

Embodiment 3

[0043] This embodiment provides a method for preparing a graphene-coated carbon nanofiber / sulfur composite microsphere material, and the specific steps are as follows:

[0044] S1. Mix carbon nanofibers and starch evenly at a ratio of 1:4.5, then add them into deionized water, and perform ultrasonic dispersion for 2.5 hours to obtain a uniform mixed solution. The viscosity of the mixed solution is suitable for electrospinning;

[0045] S2. Using the electrospinning technology to prepare the mixed solution obtained in step S1 to obtain carbon microspheres, wherein the specific steps of the electrospinning technology are: first put the mixed solution into a syringe, and the inner diameter of the nozzle of the syringe is 4 mm, and fix the syringe On the support, the nozzle is aimed at the circular receiving plate, the distance between the nozzle and the circular receiving plate is 20cm, and the circular receiving plate is rotated at a speed of 15r / min, and the spinning is carried ...

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PUM

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Abstract

The invention discloses a preparation method of a graphene-coated carbon nanofiber / sulfur composite material. The preparation method comprises the steps of performing uniform mixing on carbon nanofibers and starch, and then adding deionized water and performing ultrasonic dispersion to obtain a uniform mixed solution; next, adopting an electrospinning technique to prepare the obtained mixed solution into carbon microspheres, and next, performing carbonizing treatment in an inert gas atmosphere to obtain spherical carbon microspheres; performing heat treatment on the obtained carbon microspheres and elementary sulfur to obtain carbon / sulfur composite microspheres; and finally, performing mixing on the obtained carbon / sulfur composite microspheres and a graphene oxide water solution and thenadding a reducing agent for reduction, performing stirring to realize complete reaction, and carrying out filtering and drying to obtain the graphene-coated carbon nanofiber / sulfur composite material. When the graphene-coated carbon nanofiber / sulfur composite material is used as the positive electrode material of a lithium-sulfur battery, high initial charging-discharging specific capacity and excellent capacity retention ratio are achieved; and in addition, the preparation method is simple and easy to implement, low in cost, green and environment friendly, and high in application prospect.

Description

technical field [0001] The invention belongs to the technical field of electrode materials, and more specifically relates to a graphene-coated carbon / sulfur composite material and a preparation method thereof. Background technique [0002] With the increasing demand for energy consumption in the world, the oil resources that can be developed and utilized are increasingly depleted, while the environmental pollution is becoming more and more serious. Therefore, the use of electrochemical energy storage technology to store and reuse clean solar energy and wind energy is undoubtedly the solution to this problem in the 21st century. In addition, mobile electronic devices and electric vehicles that affect people's lives also put forward higher requirements for future electrochemical energy storage technology. All of these require safe, low-cost, high-energy-density and long-life secondary batteries to be realized. Among many energy storage methods, lithium-ion batteries occupy a ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/052
CPCH01M4/362H01M4/38H01M4/62H01M4/625H01M4/628H01M10/052Y02E60/10
Inventor 林前锋
Owner HUNAN GUOSHENG GRAPHITE TECH CO LTD
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