Carbon-coated aluminum foil and preparation method thereof

Abstract

The invention provides a carbon-coated aluminum foil and a preparation method thereof. The carbon-coated aluminum foil is composed of a carbon layer of the carbon-coated aluminum foil and an aluminum foil which are combined in a mechanical interlocking mode. The invention also relates to a preparation method of the carbon-coated aluminum foil. The preparation method comprises the following steps: step 1, carrying out surface treatment on the surface of the aluminum foil: carrying out physical texturing or chemical etching treatment; 2, spraying a solvent on the surface of the aluminum foil; step 3, uniformly spraying carbon powder on the surface of the aluminum foil, and carrying out first baking and drying; 4, the aluminum foil is subjected to rolling treatment; and 5, baking and drying the aluminum foil for the second time to obtain the carbon-coated aluminum foil. According to the method, rolling treatment is adopted, in order to force the carbon powder and the aluminum foil to be tightly combined and also in order to enable the carbon powder and the aluminum foil to generate irreversible deformation, a mechanical interlocking structure is constructed at the micro pits, the adhesive force of the coating and the aluminum foil is enhanced, and therefore the purposes that the coating is firm and not prone to falling off are achieved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries; in particular, it relates to a carbon-coated aluminum foil and a preparation method thereof. Background technique [0002] Compared with traditional batteries, lithium-ion batteries have the following advantages: large volume energy density and mass energy density, and no memory effect. The application range of lithium-ion batteries is also very wide, such as: electric vehicles and boats, electric tools, energy storage, wearable devices, etc. The current collector plays an important role in the lithium-ion battery. It is not only the carrier of the active material, but also shoulders the mission of collecting the current generated by the active material of the battery and outputting it outward. Therefore, the current collector should be in full contact with the active material, and the internal resistance should be as small as possible. [0003] The active material slurry is directly coated...

AI Technical Summary

Problems solved by technology

[0003] The active material slurry is directly coated on the current collector. Due to insufficient contact between the active particles and the current collector or the conductive layer, the internal resistance of the battery will increase, which will seriously affect the rate and cycle performance of the battery.

At present, the main methods to solve the above technical problems in the industry are: (1) Coating and modifying aluminum foil by using a conductive agent. In order to increase the coating effect, a large amount of binders, dispersants, surfactants, etc. will be used. The method will isolate the conductive contact between the positive electrode active material and the aluminum foil and the conductive layer, which will be unfavorable for improving the performance of the battery; at the same time, it also increases the preparation cost; (2) directly vapor-depositing conductive carbon on the aluminum foil, this method requires high temperature Vacuum equipment can be completed, which greatly increases equipment investment and energy consumption; (3) using high temperature, the mixed carbon powder is coated on the aluminum foil, and then the temperature is raised for heat treatment to prepare carbon-coated aluminum foil. This method requires the use of high-temperature equipment It can be completed, which not only increases the equipment cost, but also consumes a large amount of energy; meanwhile, the aluminum foil prepared by this method is not effective, and the coating is easy to fall off; (4) the organic carbon source is directly coated on the surface of the aluminum foil, Then carry out high-temperature carbonization treatment, which requires the use of high-temperature equipment and consumes a lot of energy

[0004] Based on the deficiencies in the above-mentioned existing technologies, there is an urgent need for a method that does not affect the conductive contact between the positive electrode active material and the aluminum foil and the conductive layer, and can solve the problem of poor coating effect and easy peeling off of the coating, and has low cost without high cost. Method of making the device

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