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A high-sulfur-loaded lithium-sulfur battery positive electrode sheet and preparation method thereof

A technology of lithium-sulfur battery and positive electrode sheet is applied in the field of positive electrode sheet and preparation of high-sulfur-loaded lithium-sulfur battery, which can solve the problem of difficulty in realizing high areal density electrode sheet preparation, easy cracking of electrode coating layer, poor fluidity of slurry, etc. problems, to achieve the effect of inhibiting the "shuttle" effect, ensuring the consistency of the slurry, and ensuring the coating processability.

Active Publication Date: 2021-08-03
AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, some structural characteristics of carbon materials also introduce many difficulties to the preparation of positive electrodes.
For example, (1) carbon materials with large specific surface area and high porosity have high liquid absorption, resulting in poor slurry fluidity, which makes it difficult to coat on existing coating machines; (2) sulfur and carbon materials have low density and are difficult to sieve by gravity , it is easy to introduce coarse particles into the final slurry; (3) The solid content of the slurry is low, the amount of glue absorption is high, the drying time is long, and the coating layer of the pole piece is easy to crack and lose powder, etc.
Especially when NMP solvent is used, the above problems are more prominent, making it difficult to realize the preparation of high surface density pole pieces

Method used

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  • A high-sulfur-loaded lithium-sulfur battery positive electrode sheet and preparation method thereof

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Effect test

Embodiment 1

[0027] 6mg / cm 2 (Single-sided sulfur loading) The preparation of the sulfur-loading pole piece, in the material that constitutes the positive pole piece, the mass ratio of elemental sulfur, Ketjen carbon (ECP-600JD), carbon nanotubes, graphene, and binder PVDF is : 8.5:1:0.5:0.5:2; adopt the steps of the inventive method as follows:

[0028] Step 1: Use a vibrating sieve to sieve the sulfur-carbon composite material to remove foreign matter.

[0029] Step 2. Add PVDF glue and graphene conductive paste to the planetary mixer, stir and disperse, the dispersion speed is 3000rpm, and the dispersion time is 30min;

[0030] Step 3: Add sulfur-carbon composite material, stir to disperse, wet and mix to prepare premixed slurry. Dispersion speed 3000rpm, dispersion time 2h;

[0031] Step 4. Transfer the above-mentioned premixed positive electrode slurry to a ball mill tank, cover and seal it, place it in an oven at 150°C for a long enough time, and then quickly transfer it to a ball...

Embodiment 2

[0035] 7mg / cm 2 (Single-sided sulfur loading) The preparation of the sulfur-loading pole piece, in the material that constitutes the positive pole piece, the mass ratio of elemental sulfur, Ketjen carbon (ECP-600JD), carbon nanotubes, graphene, and binder PVDF is : 8.5:0.7:0.8:0.3:1.5; adopt the steps of the inventive method as follows:

[0036] Step 1: Use a vibrating sieve to sieve the sulfur-carbon composite material to remove foreign matter.

[0037] Step 2: Add PVDF glue and graphene conductive paste to the planetary mixer, stir and disperse, the dispersion speed is 3000rpm, and the dispersion time is 30min.

[0038] Step 3: Add sulfur-carbon composite material, stir to disperse, wet and mix to prepare premixed slurry. Dispersion speed 3000rpm, dispersion time 2h;

[0039] Step 4. Transfer the above-mentioned premixed positive electrode slurry to a ball mill tank, cover and seal it, place it in an oven at 150°C for a long enough time, and then quickly transfer it to a ...

Embodiment 3

[0043] 8mg / cm 2 (Single-sided sulfur loading) The preparation of the sulfur-loading pole piece, in the material that constitutes the positive pole piece, the mass ratio of elemental sulfur, Ketjen carbon (ECP-600JD), carbon nanotubes, graphene, and binder PVDF is : 8.5:0.6:0.4:0.2:0.8; adopt the steps of the inventive method as follows:

[0044] Step 1: Use a vibrating sieve to sieve the sulfur-carbon composite material to remove foreign matter.

[0045] Step 2: Add PVDF glue and graphene conductive paste to the planetary mixer, stir and disperse, the dispersion speed is 3000rpm, and the dispersion time is 30min.

[0046]Step 3: Add sulfur-carbon composite material, stir to disperse, wet and mix to prepare premixed slurry. Dispersion speed 3000rpm, dispersion time 2h;

[0047] Step 4. Transfer the above-mentioned premixed positive electrode slurry to a ball mill tank, cover and seal it, place it in an oven at 150°C for a long enough time, and then quickly transfer it to a b...

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Abstract

The invention discloses a positive electrode sheet of a lithium-sulfur battery with high sulfur loading and a preparation method thereof. The positive electrode sheet includes a sulfur-carbon composite material, graphene, a binder (PVDF), and an aluminum foil current collector. First, add an appropriate amount of PVDF glue and graphene conductive paste to the planetary mixer, stir and disperse for a long enough time; then add sulfur-carbon composite materials, stir and disperse for a long enough time; The final positive electrode slurry was obtained by vacuum filtration; the slurry was coated on aluminum foil with a transfer coating machine, and dried at low temperature to obtain a pole piece. The prepared positive electrode sheet has high sulfur loading capacity, good flexibility, and outstanding electrochemical performance, and the energy density of a lithium-sulfur battery assembled by using the electrode sheet can reach more than 400 wh / kg. The preparation method of the positive electrode sheet is simple, and industrial scale production can be realized.

Description

technical field [0001] The invention relates to a high-sulfur-loaded lithium-sulfur battery cathode sheet and a preparation method thereof, belonging to the technical field of battery manufacturing. Background technique [0002] With the increasingly serious energy crisis, lithium-ion batteries with high specific energy, long cycle life, safety, and environmental protection have attracted more and more attention. At present, they have been widely used in 3C digital products, power batteries and energy storage, etc. field. However, with the continuous emergence of new technologies and new technology products, people have put forward higher requirements on the energy density of batteries. A lithium-sulfur battery is a lithium battery that uses elemental sulfur as the positive electrode active material and metallic lithium as the negative electrode active material. Its theoretical specific energy reaches 2600Wh / kg, which is 6 to 13 times the energy density of conventional lit...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/133H01M4/134H01M4/1393H01M4/1395H01M4/36H01M4/38H01M4/583H01M10/052
CPCH01M4/133H01M4/134H01M4/1393H01M4/1395H01M4/366H01M4/386H01M4/583H01M10/052H01M2004/028Y02E60/10
Inventor 南文争燕绍九王继贤彭思侃陈翔齐新
Owner AVIC BEIJING INST OF AERONAUTICAL MATERIALS