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Flexible graphene current collector and active material integrated electrode pole piece and preparation method thereof

An electrode pole piece, flexible graphite technology, applied in battery electrodes, electrode carriers/current collectors, non-aqueous electrolyte battery electrodes, etc., can solve battery performance rate performance limitations, increase active material adhesion, limit battery energy density, etc. problems, to achieve great application value, improve cycle life and safety, and enhance the effect of electrical conductivity

Active Publication Date: 2015-07-29
INST OF METAL RESEARCH - CHINESE ACAD OF SCI +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At the same time, due to the limited contact area between the metal current collector and the active material, the interface resistance is large, and the performance of the battery under high current charge and discharge conditions (ie, the rate performance) is limited.
In addition, due to the high density of metal current collectors, the proportion of active materials in the entire electrode will be reduced, which limits the further improvement of battery energy density.
[0004] In view of the above problems, the contact between the current collector and the active material can be improved by modifying the surface of the metal current collector, and the internal resistance of the battery can be reduced. contact area, or coating the surface of the metal current collector with a conductive coating to increase the adhesion of the active material, etc. Although these methods have achieved certain results, due to the limitations of the metal current collector itself, it is difficult to further increase the energy density of the battery. Big
In addition, these methods are not suitable for flexible batteries that need to be bent multiple times during use.

Method used

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  • Flexible graphene current collector and active material integrated electrode pole piece and preparation method thereof
  • Flexible graphene current collector and active material integrated electrode pole piece and preparation method thereof
  • Flexible graphene current collector and active material integrated electrode pole piece and preparation method thereof

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[0035] The embodiment of the present invention also provides a method for preparing an electrode sheet integrated with a flexible graphene current collector and an active material for a lithium battery, which also includes a method for preparing a graphene current collector layer. The preparation method of the graphene current collector layer comprises: mixing graphene with a solvent, and dispersing to form a uniform and stable solution. The solvent is preferably one or more of water, ethanol, acetone or N-methylpyrrolidone. The amount of solvent added will affect the dispersion effect of graphene in it, so it should not be too small, so the mass ratio of graphene:solvent=1:(1-20) is preferred. In order to obtain a more fine and uniform graphene solution, the dispersion strength can be properly enhanced and the dispersion time can be prolonged. Since the graphene current collector layer in the present invention is prepared by vacuum filtration, all solvents can be recovered a...

Embodiment 1

[0044] Weigh 20 mg of graphene powder and add it to 50 mL of N-methylpyrrolidone, ultrasonically disperse for 0.5 h to obtain a uniform graphene solution, and suction filter the graphene solution into a polyvinylidene fluoride filter membrane with a pore size of 0.45 μm and a diameter of 50 mm Above, the graphene current collector layer is obtained; the commercialized lithium titanate powder, conductive carbon black, and binder PVDF are stirred and mixed in the solvent NMP according to the mass ratio of 8:1:1 to make a uniform active electrode slurry Pour the slurry on the graphene current collector layer and continue suction filtration. After the solvent is exhausted, put it together with the filter membrane in a 60°C oven for drying. After drying, it is peeled off from the filter membrane and rolled. Obtain the graphene current collector-lithium titanate negative pole sheet, such as Figure 4 shown.

[0045] The electrode pole pieces prepared above were cut and assembled in...

Embodiment 2

[0052] Weigh 20 mg of graphene powder and add it to 80 mL of N-methylpyrrolidone, ultrasonically disperse for 0.5 h to obtain a uniform graphene solution, and suction filter the graphene solution into a polyvinylidene fluoride filter membrane with a pore size of 0.22 μm and a diameter of 50 mm Above, the graphene current collector layer is obtained; the commercialized lithium iron phosphate powder, conductive carbon black, and binder PVDF are stirred and mixed in the solvent NMP according to the mass ratio of 8:1:1 to make a uniform active electrode slurry Pour the slurry on the graphene current collector layer and continue suction filtration. After the solvent is exhausted, put it together with the filter membrane in a 60°C oven for drying. After drying, it is peeled off from the filter membrane and rolled. A graphene current collector-lithium iron phosphate positive electrode sheet is obtained.

[0053] The electrode pole pieces prepared above were cut and assembled into but...

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Abstract

The present invention discloses a flexible graphene current collector and active material integrated electrode pole piece and a preparation method thereof. The flexible graphene current collector and active material integrated electrode pole piece comprises a graphene current collector layer and an active material layer, wherein graphene is subjected to dispersion and vacuum suction filtration to prepare the graphene current collector layer, the active electrode material layer is subjected to suction filtration onto the graphene current collector through the slurry, and drying and roll pressing are performed to prepare the integrated flexible electrode pole piece. According to the present invention, the used graphene has good electrical conductivity and good thermal conductivity so as to effectively improve the comprehensive performance of the battery; with the vacuum suction filtration method, the active material can closely contact the graphene current collector so as to effectively reduce the interface resistance, such that the internal resistance of the battery is reduced, the adhesion strength between the materials is enhanced, and the active material can not shed from the current collector during the charging and discharging process; and the electrode pole piece has good flexibility and is suitable for flexible batteries, and the preparation method is simple, is easy to control, can achieve mass and low-cost production, and can be applied to a variety of electrode materials.

Description

technical field [0001] The invention relates to the field of energy storage devices and related materials, in particular to a flexible graphene current collector and active material integrated electrode pole piece for a lithium battery and a preparation method thereof. Background technique [0002] With the increasingly severe energy and environmental problems in today's world, people's demand for clean, efficient and renewable energy continues to increase, and the efficient conversion and storage of energy has also attracted increasing attention. As an important energy storage device, lithium-ion secondary batteries have been widely used in various portable electronic products due to their outstanding advantages such as high capacity, long cycle life, low self-discharge rate and no memory effect. With the continuous development of flexible / foldable electronic devices in recent years, the development of flexible lithium-ion batteries with high energy density (that is, high c...

Claims

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Application Information

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IPC IPC(8): H01M4/13H01M4/66H01M4/139
CPCH01M4/133H01M4/139H01M4/66H01M10/052Y02E60/10
Inventor 李峰石颖闻雷裴嵩峰黄坤成会明
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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