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Preparation method and applications of battery graphene-base current collector

A graphene-based, current collector technology, applied in the field of electrochemical cells, can solve the problems of separation of electrode active materials and current collectors, affecting the energy density of pole pieces, high density of metal current collectors, etc. The effect of great application value and simple preparation process

Inactive Publication Date: 2015-02-11
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Such a process has the following defects: 1) The contact area between the metal current collector and the electrode active material particles is limited, and the interface resistance is large, which causes an increase in the internal resistance of the battery. Microcracks are generated between the material and the current collector, causing the separation of the electrode active material and the current collector, which leads to the deterioration of the performance of the battery; 2) The metal current collector itself has a high density, so that the mass fraction of the electrode active material in the overall pole piece 3) Under bending conditions, the electrode active material is easily separated from the metal current collector
In view of the above problems, some problems can be solved by modifying the surface of the current collector, but it is difficult to fundamentally change

Method used

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  • Preparation method and applications of battery graphene-base current collector
  • Preparation method and applications of battery graphene-base current collector
  • Preparation method and applications of battery graphene-base current collector

Examples

Experimental program
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Embodiment 1

[0039] Add 200mg of graphene into 400mL ethanol and disperse uniformly by ultrasonic for 0.5h (the content of graphene in the dispersion is 0.5mg / mL) and filter it onto the continuously rolling polyvinylidene fluoride membrane to form long strips of graphene. After rolling, it was separated from the polyvinylidene fluoride film, and dried in vacuum at 70° C. for 12 hours to obtain the graphene current collector. The scanning electron microscope picture of the obtained graphene current collector is shown in Figure 4 (a-b), it can be seen that the graphene sheets are tightly stacked, and the lateral size of the graphene-based current collector is 15-25 microns. Carry out stress-strain performance test to it, described graphene-based current collector can bear the pulling force of 1.8MPa at most, and cellulose paper can bear the pulling force of 0.75MPa at most, as Figure 5 , showing its high mechanical strength properties.

[0040] On the graphene-based current collector, th...

Embodiment 2

[0044] The difference from Example 1 is that the lithium iron phosphate in Example 1 is replaced with lithium titanate negative electrode material, and it is mixed with conductive carbon black and binder (sodium carboxymethyl cellulose) at a ratio of 8:1:1 After the weight ratio is mixed and uniformly dispersed in NMP to form a slurry, it is sprayed on a graphene current collector with a thickness of 25 μm by spraying, and dried in an oven at 120 ° C for 12 hours to obtain a graphene-based current collector / titanium Anode materials for lithium-ion batteries, and their electrochemical performances were characterized. The electrode structure at 35mA·g -1 Under the current density, the initial discharge capacity is 167mAh·g -1 , the capacity increased to 175mAh·g after the second time -1 above. The discharge capacities at various current densities are shown in Figure 8 , at 1750mA·g -1 The discharge capacity is 85mAh·g at the current density -1 , at 3500mA·g -1 The discha...

Embodiment 3

[0048] The difference from Example 1 is that the lithium iron phosphate in Example 1 is replaced by lithium manganate, and after being uniformly dispersed in DMF, an electrode sheet is formed on a graphene current collector with a thickness of 20 μm by scraping , used to test the battery performance of the lithium manganate cathode material, the battery performance similar to that of Example 1 can be obtained, and it is obviously better than the battery performance of Comparative Example 1.

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Abstract

The invention discloses a preparation method and applications of a battery graphene-base current collector, and belongs to the field of electrochemical battery. The provided current collector is suitable for lithium ion battery and lithium-sulfur battery, is prepared by dispersing graphite, subjecting graphite to suction filtration, and rolling the graphite, has a thickness of 15 to 25 [mu]m, and has high mechanical strength. When the provided graphene-base current collector is applied to a lithium ion battery or a lithium-sulfur battery, the weight of the lithium ion battery or the lithium-sulfur battery is effectively reduced, the energy density of the lithium ion battery or the lithium-sulfur battery is improved. Moreover, the provided current collector has a very strong electrolyte absorbing and storing performance, so the strong current charging / discharging performance of battery using the provided current collector is improved, and the properties of multiple electrode materials are all largely improved. The preparation process of the provided current collector is simple and controllable, and furthermore the preparation method can be applied to massive and low-cost industrial production, and thus has a high application value.

Description

technical field [0001] The invention belongs to the technical field of electrochemical batteries, and in particular relates to a preparation method and application of a graphene-based current collector for batteries. Background technique [0002] High-capacity batteries are widely used in electronic products. In order to meet the growing needs, it is one of the development trends in the field of new energy to develop portable secondary batteries with high energy density, power density and good cycle stability, such as lithium-ion batteries and the next generation of high-energy lithium-sulfur batteries. . The main components of lithium-ion batteries and lithium-sulfur batteries include electrode active materials (electrode materials that participate in electrochemical reactions to provide energy) and inactive materials (materials used for battery assembly and packaging, which are also important components of batteries and play an extremely important role in performance. im...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/66H01M4/139H01M4/62
CPCH01M4/139H01M4/663Y02E60/10
Inventor 李峰李璐周光敏裴嵩峰黄坤成会明
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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