Integrated flexible electrode

A flexible electrode and active material technology, applied in the direction of battery electrodes, electrode carriers/collectors, non-aqueous electrolyte battery electrodes, etc., can solve the problem of few high-performance flexible lithium-sulfur battery electrode materials, reduce lithium battery energy density, Problems such as high fluid density, to achieve the effect of increasing specific capacity, reducing weight, and increasing interface bonding strength

Active Publication Date: 2015-09-16
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Abstract
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Problems solved by technology

The lithium storage mechanism of the positive electrode material of the current commercial secondary lithium battery is the intercalation reaction mechanism, and the number of electrons transferred in the electrochemical process is less than one electron. Therefore, the mass specific energy density of the secondary lithium battery assembled with these electrode materials is generally lower than 200Wh / kg, its performance has reached or is close to the limit of the theoretical capacity of the material, so the cathode material has become the bottleneck for the further improvement of the performance of the secondary lithium battery
The secondary lithium battery assembly process is to mix electrode materials, conductive agents and binders and coat them on the metal current collector. Because the metal current collector has a high density and does not contribute to the capacity, the energy density of the lithium battery is greatly reduced.
The solution to the problem of lithium-sulfur batteries is also mainly focused on the design of electrode materials and electrolyte optimization, and rarely prepares high-performance flexible lithium-sulfur battery electrode materials from structural design

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Add 700mg of graphene and 300mg of polyvinylidene fluoride to N-methylpyrrolidone and disperse uniformly by ultrasonication for 0.5h (the content of graphene in the dispersion is 1mg / mL) and scrape it on the polypropylene microporous membrane, dry and remove the solvent Graphene-coated materials can be obtained such as image 3 (a), the thickness of the graphene layer is 30 μm. On the surface of the graphene layer, the slurry formed by mixing sulfur: conductive carbon black: binder (polyvinylidene fluoride) in a weight ratio of 7:2:1 is coated to form a carbon / sulfur active material on the surface of the graphene layer layer, dried under vacuum at 70°C for 12 hours, the obtained materials are shown in image 3 (b). The cross-sectional scanning electron microscope image of the obtained sulfur cathode integrated flexible electrode is shown in Figure 4 , the stacked structure of graphene sheets can be seen. The uniform coating of sulfur, conductive carbon black and bi...

Embodiment 2

[0046] Stir and mix commercial lithium iron phosphate powder, conductive carbon black, and binder PVDF in the solvent NMP according to the mass ratio of 8:1:1 to make a uniform active electrode slurry, and scrape the slurry on The polypropylene microporous membrane and the graphene layer are put on the 60°C oven to dry to obtain the lithium iron phosphate cathode integrated flexible electrode. After cutting the electrode pole pieces prepared above, they were assembled into button half cells for charge and discharge cycle tests at different rates, and it was found that the electrodes were -1 Under the current density, the discharge capacity can reach 140mAh·g -1 , at 1700mA·g -1 Under the high current density, the discharge capacity of lithium iron phosphate is 90mAh·g -1 .

Embodiment 3

[0050] Stir and mix commercial lithium manganate powder, conductive carbon black, and binder PVDF in the solvent NMP according to the mass ratio of 85:7:8 to make a uniform active electrode slurry, and scrape the slurry on The polypropylene microporous membrane and the graphene layer are put on the 60°C oven to dry to obtain the lithium manganate cathode integrated flexible electrode. A half-cell performance test was performed on it, and the rate and cycle performance similar to that of Example 2 can be obtained, and the result is better than the battery performance of the aluminum foil current collector-lithium manganate positive electrode under the same conditions.

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Abstract

The invention discloses an integrated flexible electrode and belongs to the technical field of electrochemical cells. The integrated flexible electrode is composed of three layers which are successively a polymer layer, a graphene layer and an active material layer. According to the invention, the multi-component integrated design is realized. The graphene layer is formed by dispersing and coating graphene onto the polymer layer. The active material layer is formed by coating slurry onto the graphene layer. After drying, the integrated flexible electrode material is obtained. The integrated flexible electrode material has excellent flexibility and tensile strength and is applicable to flexible cells. A preparation method of the integrated flexible electrode is simple and easy to control, can be applied to various electrode materials and has potential application value. Mass and low-cost preparation can be realized.

Description

technical field [0001] The invention relates to the technical field of energy storage devices and related materials, in particular to an integrated flexible electrode. Background technique [0002] With people's demand for various thin, flexible / foldable electronic devices, higher requirements are put forward for the development of small, light, flexible secondary lithium batteries with high energy density, power density and bending stability. Flexible electrodes are one of the key factors in the development of high-performance flexible secondary batteries. The lithium storage mechanism of the positive electrode material of the current commercial secondary lithium battery is the intercalation reaction mechanism, and the number of electrons transferred in the electrochemical process is less than one electron. Therefore, the mass specific energy density of the secondary lithium battery assembled with these electrode materials is generally lower than 200Wh / kg, its performance ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/66H01M2/16
CPCH01M4/13H01M4/133H01M4/137H01M4/66H01M10/0525H01M50/409Y02E60/10
Inventor 李峰周光敏李璐裴嵩峰黄坤宋仁升成会明
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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