Graphene-based porous carbon flake material, and preparation method and application thereof

A technology of graphene and sheet materials, applied in electrical components, non-aqueous electrolyte batteries, circuits, etc., can solve the problems of inability to meet the long-term cycle and commercialization requirements of lithium-sulfur batteries, poor battery cycle performance, and low sulfur utilization rate. To achieve the effect of suppressing the shuttle effect, improving the utilization rate and reducing the cost

Inactive Publication Date: 2018-08-03
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

First, the conductivity of elemental sulfur is very poor, resulting in a relatively low utilization rate of sulfur in the charging and discharging process of lithium-sulfur batteries
Second, the discharge intermediate polysulfides generated during charging and discharging are easily dissolved in the electrolyte and shuttle between the positive and negative electrodes, resulting in poor cycle performance of the battery
However, simple porous carbon materials can only act as a physical barrier to polysulfides, and cannot well limit the dissolution and overflow of polysulfide ions, and cannot meet the long-term cycle and commercialization requirements of lithium-sulfur batteries.

Method used

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  • Graphene-based porous carbon flake material, and preparation method and application thereof
  • Graphene-based porous carbon flake material, and preparation method and application thereof
  • Graphene-based porous carbon flake material, and preparation method and application thereof

Examples

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Embodiment 1

[0035] (1) Preparation of graphene-based porous carbon sheet materials

[0036] At room temperature, 5 mL of graphene oxide solution (10 mg / mL) was added dropwise to 200 mL of methanol solution, ultrasonically dispersed for 5 h, then 300 mg of polyvinylpyrrolidone was added, and stirred for 1 h to obtain mixed solution 1; 3.09 g of Zn(NO 3 ) 2 ·6H 2 O and 0.61g Co(NO 3 ) 2 ·6H 2 O was dissolved in the above mixed solution 1, and stirred at room temperature for 3 h to obtain mixed solution 2; then 60 mL of 2-methylimidazole (4.25 g) in methanol was quickly added to the above mixed solution 2, and stirred at room temperature for 30 min until precipitation occurred. Centrifuge after standing for 6 hours, wash the precipitate with anhydrous methanol 3 times to remove impurities, and freeze-dry the obtained precipitate in a freeze dryer for 24 hours to obtain an intermediate product; calcinate the intermediate product at 950°C for 3 hours in a tube furnace with a nitrogen atmos...

Embodiment 2

[0049] (1) Preparation of graphene-based porous carbon sheet materials

[0050] At room temperature, 5 mL of graphene oxide solution (10 mg / mL) was added dropwise to 200 mL of methanol solution, ultrasonically dispersed for 5 h, then 300 mg of polyvinylpyrrolidone was added, and stirred for 1 h to obtain mixed solution 1; 2.48 g of Zn(NO 3 ) 2 ·6H 2 O and 1.21g Co(NO 3 ) 2 ·6H 2 O was dissolved in the above mixed solution 1, and stirred at room temperature for 3 h to obtain mixed solution 2; then 60 mL of 2-methylimidazole (4.25 g) in methanol was quickly added to the above mixed solution 2, and stirred at room temperature for 30 min until precipitation occurred. After standing for 6 hours, centrifuge, wash the precipitate with anhydrous methanol 3 times to remove impurities, and place the obtained precipitate in a freeze dryer for 24 hours to obtain the intermediate product; the intermediate product is calcined at 950°C for 3 hours in a tube furnace with a nitrogen atmosp...

Embodiment 3

[0063] (1) Preparation of graphene-based porous carbon sheet materials

[0064] At room temperature, 5 mL of graphene oxide solution (10 mg / mL) was added dropwise to 200 mL of methanol solution, ultrasonically dispersed for 5 h, then 300 mg of polyvinylpyrrolidone was added, and stirred for 1 h to obtain mixed solution 1; 3.53 g of Zn(NO 3 ) 2 ·6H 2 O and 0.17g Co(NO 3 ) 2 ·6H 2 O was dissolved in the above mixed solution 1, and stirred at room temperature for 3 h to obtain mixed solution 2; then 60 mL of 2-methylimidazole (4.25 g) in methanol was quickly added to the above mixed solution 2, and stirred at room temperature for 30 min until precipitation occurred. After standing for 6 hours, centrifuge, wash the precipitate with anhydrous methanol 3 times to remove impurities, and place the obtained precipitate in a freeze dryer for 24 hours to obtain the intermediate product; the intermediate product is calcined at 950°C for 3 hours in a tube furnace with a nitrogen atmosp...

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Abstract

The invention relates to a graphene-based porous carbon flake material, and a preparation method and application thereof, belonging to the technical field of battery materials. The graphene-based porous carbon flake material is of a two-dimensional lamellar structure; porous carbon flakes are distributed on the upper and lower surfaces of a graphene layer; and the graphene-based porous carbon flake material is doped with cobalt-nitrogen. The material has a uniform porous structure, a high cobalt-nitrogen content and continuous electronic conductivity. The rich open-framework structures and high cobalt-nitrogen content of the material allow better physicochemical adsorption effect to be exerted on polysulfide ions, so the polysulfide ions are hindered in shuttling back and forth. At the same time, the material has good electronic conductivity and can function as a secondary current collector, which is beneficial for improving the utilization rate of a sulfur positive electrode material.The material is applied to a lithium-sulfur battery separator and can suppress the shuttle effect of the polysulfide ions, improve the utilization rate of the active substance sulfur and improve thecycle stability of a lithium-sulfur battery, so the electrochemical performance of the lithium-sulfur battery can be improved.

Description

technical field [0001] The invention relates to a graphene-based porous carbon sheet material, a preparation method and an application thereof, and belongs to the technical field of battery materials. Background technique [0002] Since the advent of commercialized lithium-ion batteries in the 1990s, they have been widely used in civilian consumer electronics and military weapons and equipment. However, with the rapid development of electric vehicles, hybrid vehicles and stationary energy storage devices, people have put forward higher requirements for the energy density of lithium batteries. The current commercial lithium-ion batteries are limited by their theoretical capacity, which makes it difficult to meet the requirements of high energy density for practical applications. Therefore, it is particularly important to develop new energy storage systems with high energy density and low cost. Recently, lithium-sulfur batteries have attracted extensive attention from resear...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M10/052H01M50/431H01M50/449
CPCH01M10/052H01M50/431H01M50/449Y02E60/10
Inventor 陈人杰李万隆叶玉胜曲薇李丽吴锋
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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