Carbon-sulfur composite positive electrode for lithium-sulfur battery and preparation method of carbon-sulfur composite positive electrode

A carbon-sulfur composite and lithium-sulfur battery technology, applied in battery electrodes, lithium batteries, non-aqueous electrolyte battery electrodes, etc., can solve the problem of large-scale preparation of unfavorable carbon-sulfur composite positive electrodes, increase the cost of electrode production, and increase the complexity of the preparation process, etc. problems, to achieve the effect of rational design and preparation, high sulfur utilization rate, and multiple electrochemical active sites

Active Publication Date: 2020-12-11
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

However, the introduction of the above-mentioned complex nanostructure components increases the complexity of the preparation process and increases the cost of electrode fabrication, which is not conducive to the large-scale preparation of carbon-sulfur composite cathodes, and therefore is difficult to be practically applied to the construction of high-energy-density lithium-sulfur batteries.

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  • Carbon-sulfur composite positive electrode for lithium-sulfur battery and preparation method of carbon-sulfur composite positive electrode

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preparation example Construction

[0038] A method for preparing a lithium-sulfur battery composite positive electrode provided by the invention comprises the following steps:

[0039]1) Mix the carbon material I used in the carbon-sulfur composite layer with elemental sulfur in proportion, seal and heat to 155° C., and heat-melt at a constant temperature for 1 to 5 hours to prepare a carbon-sulfur composite. Add a certain amount of water to the carbon-sulfur composite to obtain a dispersion with a solid content of 20-40%, mill the dispersion for 1-5 hours, add a water-based binder, and homogenize for 10-120 minutes to prepare a carbon-sulfur composite slurry The sulfur in the carbon-sulfur composite slurry is sublimed sulfur; the carbon materials used in the carbon-sulfur composite layer slurry are carbon nanotubes, graphene, carbon black, mesocarbon microspheres, fullerenes, porous carbon and activated carbon One or more of them; the water-based binder in the carbon-sulfur composite slurry is one or more of p...

Embodiment 1

[0045] Polyacrylic acid was used as the binder of the carbon-sulfur composite layer, and polytetrafluoroethylene was used as the binder of the conductive carbon layer to prepare the carbon-sulfur composite positive electrode of the lithium-sulfur battery.

[0046] Carbon nanotubes and sublimed sulfur were mixed at a mass ratio of 6:13, sealed and heated to 155°C, and melted at a constant temperature for 5 hours to prepare a carbon-sulfur composite. Adding a certain amount of water to the carbon-sulfur composite to obtain a dispersion with a solid content of 20%, milling the dispersion for 1 hour, adding polyacrylic acid with a mass fraction of 5%, and homogenizing for 10 minutes to prepare a carbon-sulfur composite slurry;

[0047] The carbon-sulfur composite slurry was scraped on a 15 μm thick aluminum foil with a scraper, and vacuum-dried at 50°C for 24 hours to prepare a carbon-sulfur composite layer. The thickness of the carbon-sulfur composite layer was 20 μm, and the mass...

Embodiment 2

[0052] Carboxymethyl cellulose was used as the binder of the carbon-sulfur composite layer, and polyvinylidene fluoride was used as the binder of the conductive carbon layer to prepare the carbon-sulfur composite positive electrode of the lithium-sulfur battery.

[0053] Graphene and sublimed sulfur were mixed at a mass ratio of 2:7, heated to 155°C, and melted at a constant temperature for 4 hours to prepare a carbon-sulfur composite. Add a certain amount of water to the carbon-sulfur complex to obtain a dispersion with a solid content of 30%, ball mill the dispersion for 2 hours, add carboxymethyl cellulose with a mass fraction of 10%, and homogenate for 30 minutes to prepare a carbon-sulfur complex slurry;

[0054] The carbon-sulfur composite slurry was scraped on a 20 μm thick aluminum foil with a scraper, and vacuum-dried at 60°C for 10 hours to prepare a carbon-sulfur composite layer. The thickness of the carbon-sulfur composite layer was 50 μm, and the mass of sulfur in...

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Abstract

The invention discloses a carbon-sulfur composite positive electrode for a lithium-sulfur battery and a preparation method of the carbon-sulfur composite positive electrode, and belongs to the technical field of lithium-sulfur batteries. The carbon-sulfur composite positive electrode consists of a carbon-sulfur composite layer and a conductive carbon layer which are sequentially coated on the current collector; the carbon-sulfur composite layer is composed of a sulfur material, a carbon material I and an aqueous binder, and the conductive carbon layer is composed of a carbon material II and anorganic binder. According to the double-layer carbon-sulfur composite positive electrode prepared by the method, the construction of a high-sulfur-capacity, high-sulfur-content, high-specific-capacity and long-cycle-life high-energy-density lithium-sulfur battery can be realized. The preparation method of the composite positive electrode is simple and convenient to operate, low in cost and easy to amplify, the design and preparation of the positive electrode of the lithium-sulfur battery are effectively promoted, and a new possibility is provided for the practicability of the lithium-sulfur battery with high energy density.

Description

technical field [0001] The invention belongs to the technical field of lithium-sulfur batteries, and in particular relates to a carbon-sulfur composite positive electrode for lithium-sulfur batteries and a preparation method thereof. Background technique [0002] High-performance rechargeable batteries play an integral role in fields such as electric vehicles, consumer electronics, and smart grids. However, the energy density of current commercialized lithium-ion batteries tends to its theoretical limit and cannot achieve more than 400Whkg -1 high energy density requirements. Lithium-sulfur batteries use sulfur element as the positive electrode active material, metal lithium as the negative electrode active material, and the theoretical energy density is as high as 2600Whkg -1 , is considered to be a promising high energy density secondary battery system and has received extensive attention. However, the practical application of lithium-sulfur batteries still faces many c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/133H01M4/62H01M4/38H01M4/587H01M4/139H01M4/1393H01M10/052
CPCH01M4/13H01M4/133H01M4/139H01M4/1393H01M4/38H01M4/587H01M4/625H01M4/621H01M4/622H01M10/052H01M2004/028H01M2004/021Y02E60/10
Inventor 黄佳琦李博权赵梦彭彦琪
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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