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

A technology of graphene coating and composite materials, which is applied in the direction of structural parts, electrical components, battery electrodes, etc., can solve the problems of increasing contact resistance and reducing battery rate performance, and achieves the advantages of inhibiting dissolution, improving electrical conductivity, and low cost Effect

Inactive Publication Date: 2020-11-06
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 / sulfur composite microsphere 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. Put the mixed solution into a three-necked flask, fix it on an ultrasonic spray device, and raise the temperature of the electromagnetic tube furnace to 550°C at a heating rate of 10°C / min under the protection of argon, and use the ultrasonic wave to dissolve the mixed solution. The solution is atomized and passed through a quartz tube in an electromagnetic tube furnace for spheroidization. After 12 hours, after the solution was completely sprayed, the tube furnace was allowed to cool naturally, and the spheroidized material on the inner wall of the q...

Embodiment 2

[0036] This embodiment provides a method for preparing a graphene-coated carbon / sulfur composite microsphere 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. Put the mixed solution into a three-necked flask, fix it on an ultrasonic spray device, and raise the temperature of the electromagnetic tube furnace to 580°C at a heating rate of 10°C / min under the protection of argon, and use the action of ultrasonic waves to dissolve the mixed solution. The solution is atomized and passed through a quartz tube in an electromagnetic tube furnace for spheroidization. After 16 hours, after the solution was completely sprayed, the tube furnace was allowed to cool naturally, and the spheroidized material on the inner wal...

Embodiment 3

[0043] This embodiment provides a method for preparing a graphene-coated carbon / 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 uniformly mixed solution. The viscosity of the mixed solution is suitable for electrospinning;

[0045]S2. Put the mixed solution into a three-necked flask, fix it on an ultrasonic spray device, and raise the temperature of the electromagnetic tube furnace to 600°C at a heating rate of 10°C / min under the protection of argon, and use the ultrasonic wave to dissolve the mixed solution. The solution is atomized and passed through a quartz tube in an electromagnetic tube furnace for spheroidization. After 18 hours, after the solution was completely sprayed, the tube furnace was allowed to cool naturally, and the spheroidized material on the inner wall of the ...

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Abstract

The invention discloses a preparation method of a graphene coated carbon / sulfur composite material. The method includes: mixing carbon nanofiber with starch evenly, then adding deionized water, and conducting ultrasonic dispersion to obtain an evenly mixed solution; then subjecting the dispersed mixed solution to atomization by an ultrasonic atomizer to form uniformly dispersed fog beads, then bringing the fog beads into a tube furnace by inert gas for drying spheroidizing treatment and carbonizing treatment in order, thus obtaining carbon microspheres; then mixing the obtained carbon microspheres with elemental sulfur for heat treatment to obtain carbon / sulfur composite microspheres; and finally mixing the obtained carbon / sulfur composite microspheres with a graphene oxide aqueous solution, then adding a reducing agent for reduction so as to obtain the graphene coated carbon / sulfur composite material. The graphene coated carbon / sulfur composite material provided by the invention has high first discharge specific capacity and good capacity retention rate when used as a lithium-sulfur battery cathode material, also has the advantages of simple and feasible preparation method, low cost, and green and environmental protection, thus having good application prospects.

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): H01M4/36
CPCH01M4/362Y02E60/10
Inventor 林前锋
Owner HUNAN GUOSHENG GRAPHITE TECH CO LTD
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