A preparation method of graphene oxide/sulfur microcapsule composite material, lithium-sulfur battery positive electrode, lithium-sulfur battery

A composite material, lithium-sulfur battery technology, used in battery electrodes, lithium batteries, non-aqueous electrolyte battery electrodes, etc. Simple process and highly reproducible results

Active Publication Date: 2021-03-16
ANHUI NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The volume expansion will lead to the rupture and pulverization of the positive electrode structure, the active material sulfur will be detached from the positive electrode, and the loss of this part of the active material will lead to permanent capacity loss.
Lithium-sulfur batteries use metal lithium as the negative electrode. In addition to the high activity of metal lithium itself, the volume of the metal lithium negative electrode will change during charging and discharging, and dendrites will easily form, which will reduce the safety.
[0005] These problems lead to low utilization of sulfur in the battery, poor cycle performance, fast capacity fading, and poor rate performance, all of which need to be further explored and solved.

Method used

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  • A preparation method of graphene oxide/sulfur microcapsule composite material, lithium-sulfur battery positive electrode, lithium-sulfur battery
  • A preparation method of graphene oxide/sulfur microcapsule composite material, lithium-sulfur battery positive electrode, lithium-sulfur battery
  • A preparation method of graphene oxide/sulfur microcapsule composite material, lithium-sulfur battery positive electrode, lithium-sulfur battery

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Embodiment 1

[0051] A preparation method of graphene oxide / sulfur microcapsule composite material, comprising the following steps:

[0052] (1) Preparation of graphene oxide: weigh 5.0g graphite and 3.75g NaNO respectively 3 Put it into a 1L beaker, stir vigorously, slowly add 150mL of concentrated sulfuric acid, stir for 0.5 hours, then slowly add 20g of KMnO 4 , Added in 0.5 hours, and continued to stir for 20 hours, because the viscosity of the reactant increased, the stirring was stopped, and a paste-like purple-red substance was obtained. After standing for 5 days, slowly add 500mL deionized water and 30mLH 2 o 2 At this time, the color of the solution becomes more obvious bright yellow. After the solution is fully reacted, it is centrifuged and washed to obtain graphene oxide. Its TEM image is as follows figure 1 shown. Ultrasonic dispersion of graphene oxide in water to prepare a graphene oxide aqueous solution with a concentration of 2 mg / mL;

[0053] (2) 0.2g photoinitiator 2...

Embodiment 2

[0059] A preparation method of graphene oxide / sulfur microcapsule composite material, comprising the following steps:

[0060] (1) The preparation of graphene oxide is the same as in Example 1. Graphene oxide was ultrasonically dispersed in water to prepare a graphene oxide aqueous solution with a concentration of 4 mg / mL.

[0061] (2) Mix 0.4g photoinitiator 2-hydroxyl-2-methylpropiophenone with 20g organic photocurable material ETPTA to obtain a mixed solution A with a photoinitiator content of 2%;

[0062] (3) Utilize liquid flooding coaxial flow focusing technology, use 2wt% polyvinyl alcohol (PVA) aqueous solution as the driving phase, graphene oxide aqueous solution with a concentration of 4 mg / mL as the internal phase, mixed solution A as the external phase, and control the internal phase The flow rate is 3mL / h, the flow rate of the external phase is 13mL / h, and the flow rate of the driving phase is 1200mL / h. When the fluid flow rate of the driving phase reaches the t...

Embodiment 3

[0066] A preparation method of graphene oxide / sulfur microcapsule composite material, comprising the following steps:

[0067] (1) The preparation of graphene oxide is the same as in Example 1. Ultrasonic dispersion of graphene oxide in water to prepare a graphene oxide aqueous solution with a concentration of 8 mg / mL;

[0068] (2) Mix 1.0g photoinitiator 2-hydroxyl-2-methylpropiophenone with 20g organic photocurable material ETPTA to obtain a mixed solution A in which the quality of photoinitiator is 5% of the mass of organic photocurable material;

[0069] (3) Utilize liquid flooding coaxial flow focusing technology, use 3wt% polyvinyl alcohol (PVA) aqueous solution as the driving phase, graphene oxide aqueous solution with a concentration of 8mg / mL as the internal phase, mixed solution A as the external phase, and control the internal phase The flow rate is 9mL / h, the flow rate of the external phase is 7mL / h, and the flow rate of the driving phase is 900mL / h. When the flu...

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Abstract

The invention discloses a preparation method of a graphene oxide / sulfur microcapsule composite material, a positive electrode of lithium-sulfur battery and the lithium-sulfur battery. The method comprises the steps: taking graphene oxide aqueous solution, an organic photocuring material solution containing a photoinitiator and a polyvinyl alcohol aqueous solution as an inner phase, an outer phaseand a driving phase; employing a liquid drive coaxial flow focusing technology, and acquiring graphene oxide microcapsules from the inner phase and the outer phase under the shearing action of the driving phase, and performing curing under the irradiation of ultraviolet light; preparing a graphene oxide / sulfur microcapsule composite material through the steps of washing, drying, high-temperature carbonization and sulfur smoking. The lithium-sulfur battery positive electrode material has good conductivity, a large amount of graphene oxide in the capsule provides a specific surface area for sulfur adsorption, the active mass of sulfur is increased, and a buffer space is provided for volume expansion of sulfur, so the electrochemical performance of a lithium-sulfur battery is improved.

Description

technical field [0001] The invention belongs to the technical field of energy storage materials, and in particular relates to a preparation method of a graphene oxide / sulfur microcapsule composite material, a positive electrode of a lithium-sulfur battery, and a lithium-sulfur battery. Background technique [0002] Due to environmental pollution and the depletion of fossil fuels, the demand for clean and renewable energy such as solar energy and wind energy has become more and more urgent, so the development of secondary energy sources with high energy density, long cycle life, high safety, green environmental protection and low cost Batteries are of great significance in the field of new energy. Lithium-ion batteries are widely used in people's daily life. With the development of society, traditional lithium-ion batteries are far from meeting people's needs for energy storage. [0003] In recent years, lithium-sulfur (Li-S) batteries have been favored due to their high en...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M4/13H01M10/052
CPCH01M4/13H01M4/362H01M4/38H01M4/628H01M10/052H01M2004/021H01M2004/028Y02E60/10
Inventor 刘金云林夕蓉韩阗利彭贞司廷李金金
Owner ANHUI NORMAL UNIV
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