Carbon-coated layer composition for debonding carbon-coated aluminum foil, preparation method of carbon-coated layer composition, debonding carbon-coated aluminum foil and debonding method of debonding carbon-coated aluminum foil

Abstract

The invention discloses a carbon-coated layer composition for a debonding carbon-coated aluminum foil, a preparation method of the carbon-coated layer composition, the debonding carbon-coated aluminum foil and a debonding method of the debonding carbon-coated aluminum foil, and relates to the field of carbon-coated aluminum foils. The carbon-coated layer composition for the debonding carbon-coated aluminum foil comprises a basic carbon-coated raw material, a low-temperature thermal curing agent and a debonding aid, the debonding aid comprises a high-temperature thermal curing agent, the curing reaction temperature of the low-temperature thermal curing agent is less than 130 DEG C, and the curing initial reaction temperature of the high-temperature thermal curing agent is greater than the curing reaction temperature of the low-temperature thermal curing agent. The low-temperature thermal curing agent is used for initiating primary curing, the high-temperature thermal curing agent is used for initiating secondary curing, but the initiation of the primary curing is just after the carbon coating layer composition is coated, so that the carbon coating layer is firmly attached to the surface of the aluminum foil base material; the initiation of secondary curing is used for embrittling the carbon coating layer between the aluminum foil base material and the positive electrode active material when the positive electrode active material needs to be recycled when the performance of the battery is reduced after multiple times of use, so that the whole piece of the positive electrode active material is stripped.

Description

Technical Field

[0001] The present application relates to the technical field of carbon-coated aluminum foil for lithium-ion batteries, and in particular to a carbon-coated layer composition for debonding carbon-coated aluminum foil and a preparation method thereof, and a debonding carbon-coated aluminum foil and a debonding method thereof. Background Art

[0002] Carbon-coated aluminum foil is now widely used in power, energy storage batteries and some consumer batteries. However, no matter how to increase performance and extend battery life, there will be a time when it needs to be recycled and reused. The current mainstream recycling method is to discharge, crush, and then chemically reduce the elements to compounds such as lithium carbonate, nitrates, sulfates, and then polymerize again. This process requires multiple chemical extraction and purification processes, which also imposes an invisible burden on the environment. Therefore, how to provide a simple process and low-cost way to recycle positive electrode active materials is of great research significance. Summary of the invention

[0003] The present application utilizes the decomposition and degradation of the carbon coating layer of the battery to achieve debonding, thereby separating the positive electrode active material from the aluminum foil substrate. The positive electrode active material can be removed from the entire surface, reducing the recycling processing steps and saving labor costs and time costs.

[0004] First, the carbon-coated layer composition for debonding carbon-coated aluminum foil provided in the present application adopts the following technical solution: A carbon coating layer composition for debonding carbon-coated aluminum foil comprises a basic carbon coating raw material, a low-temperature thermal curing agent and a debonding aid, wherein the debonding aid comprises a high-temperature thermal curing agent, the curing reaction temperature of the low-temperature thermal curing agent is less than 130°C, and the curing reaction temperature of the high-temperature thermal curing agent is greater than the curing reaction temperature of the low-temperature curing agent.

[0005] The carbon-coated layer composition for debonding carbon-coated aluminum foil of the present application uses a low-temperature thermal curing agent and a high-temperature thermal curing agent on the basis of the basic carbon-coated raw material. The curing reaction temperature of the high-temperature thermal curing agent is greater than the curing reaction temperature of the low-temperature curing agent, and different functions are achieved by utilizing the difference in the curing reaction temperature of the two. Among them, the role of the low-temperature thermal curing agent is to promote the carbon-coated layer composition coated on the surface of the aluminum foil substrate to undergo a primary curing, so as to achieve a firm adhesion of the carbon-coated layer on the surface of the aluminum foil substrate. In this process, it should be noted that the reaction temperature of the primary curing should be lower than the curing reaction temperature of the high-temperature thermal curing agent to avoid direct embrittlement of the carbon-coated layer, which affects the normal use of the battery. The role of the high-temperature thermal curing agent is to promote the secondary curing of the carbon-coated layer when the battery performance decreases and the positive active material needs to be recovered. The temperature of the secondary curing needs to be greater than or equal to the curing reaction temperature of the high-temperature thermal curing agent. At this time, the high-temperature thermal curing agent plays a role in initiating secondary curing, so that the carbon-coated layer between the aluminum foil substrate and the positive active material becomes embrittled, thereby facilitating the peeling between the aluminum foil substrate and the positive active material, which is conducive to obtaining a whole piece of positive active material, without the need for reduction and polymerization steps, greatly simplifying the recycling process and saving recycling costs.

[0006] Preferably, the curing starting reaction temperature of the high-temperature thermal curing agent is greater than 150°C.

[0007] In the present application, the curing starting reaction temperature of the high-temperature thermal curing agent is preferably greater than 150°C. By increasing the difference between the curing reaction temperatures of the high-temperature thermal curing agent and the low-temperature thermal curing agent, it is helpful to prevent the problem of partial reaction of the high-temperature thermal curing agent during a single curing reaction, and can further enhance the bonding strength between the carbon coating layer and the aluminum foil substrate, which is beneficial to extending the service life of the battery.

[0008] Further preferably, the debonding aid further comprises a lithium compound, and the lithium compound is a strong alkaline compound of lithium or a strong base weak acid salt of lithium.

[0009] In the present application, the debonding aid also includes a lithium compound. The lithium compound uses a strong alkaline compound of lithium or a strong base weak acid salt of lithium, which can catalyze the high-temperature thermal curing agent to carry out a secondary curing reaction, which is beneficial to improving the reaction efficiency of the secondary curing and shortening the reaction time of the secondary curing.

[0010] In some specific embodiments, the basic carbon-coated raw material includes a conductive agent, a binder, a dispersant and an adhesion promoter; in the carbon-coated layer composition for the debonding carbon-coated aluminum foil, the weight proportion of the conductive agent is 40~80%, the weight proportion of the binder is 15~50%, the weight proportion of the dispersant is 2~5%, the weight proportion of the adhesion promoter is 0.1~2%, the weight proportion of the low-temperature thermal curing agent is 2~5%, and the weight proportion of the debonding aid is 0.1~2%.

[0011] In some preferred embodiments, the conductive agent is a combination of any two or three of graphite, conductive carbon, and carbon nanotubes, wherein the D50 particle size range of the graphite is 2-20 μm, the particle size range of the conductive carbon is 20-50 nm, and the carbon nanotubes are multi-walled carbon nanotubes.

[0012] In the present application, the particle size range of graphite and conductive carbon is limited, which is beneficial to the uniform dispersion of the two in the carbon coating composition and to the improvement of the surface smoothness of the carbon coating. The carbon nanotubes preferably use multi-walled carbon nanotubes with higher conductivity. Among them, the conductive agent is preferably a combination of any two or three of graphite, conductive carbon and carbon nanotubes, which can better construct a conductive network and improve the rate performance of lithium batteries.

[0013] In some preferred embodiments, the binder is any one of polyacrylic acid and polyethylene acrylic acid, wherein the glass transition temperature of the polyacrylic acid is 100-150°C, and the glass transition temperature of the polyethylene acrylic acid is 120-180°C.

[0014] In the present application, the binder uses polyacrylic acid or polyethylene acrylic acid with a specific glass transition temperature, which is conducive to forming a carbon coating layer with a denser cross-linked network, improving the bonding strength between the carbon coating layer and the aluminum foil substrate, and at the same time, can improve the heat resistance of the carbon coating layer.

[0015] In some specific embodiments, the adhesion promoter is at least one of a silane coupling agent, a tetrafunctional adhesion promoter, and a polyether-modified acrylate.

[0016] In some specific embodiments, the dispersant is polyacrylic acid or carboxymethyl cellulose.

[0017] The present application provides a method for preparing a carbon-coated layer composition for debonding carbon-coated aluminum foil using the following technical scheme: A method for preparing a carbon-coated layer composition for debonding carbon-coated aluminum foil comprises the following steps: S1. After uniformly mixing the conductive agent and the diluted dispersant by high-speed shearing, the pH value is adjusted to 6.5-7.5 to obtain a carbon source; wherein the dispersant is diluted with water; S2. Adjust the pH of the binder to 6.5-7.5, then add the carbon source, stir evenly, and obtain a masterbatch; S3, adding the diluted adhesion promoter to the masterbatch, stirring evenly, to obtain a premix; in this step, the adhesion promoter is diluted with an ether alcohol diluent; S4, controlling the temperature of the premix at 10-35° C., then adding a debonding aid, and stirring evenly to obtain a debonding carbon-coated aluminum foil carbon-coated layer composition; Regarding the addition of a low-temperature thermal curing agent, when the curing reaction temperature of the low-temperature thermal curing agent is lower than 60°C, it can be added to the carbon coating composition before coating and stirred evenly; when the curing reaction temperature of the low-temperature thermal curing agent is above 60°C, it can be diluted with an alcohol ether diluent and directly mixed in step S3 or S4.

[0018] The preparation process of the carbon-coated layer composition for debonding carbon-coated aluminum foil requires attention: when the low-temperature thermal curing agent is not added before use, the adhesion promoter and the low-temperature thermal curing agent are diluted before adding to prevent the problem of premature reaction due to excessive local concentration and affecting storage stability; alternatively, the pH value of the binder with reactive functional groups is adjusted to 6.5~7.5 to prevent the problem of premature reaction during storage.

[0019] The present application provides a debonding carbon-coated aluminum foil, which comprises an aluminum foil substrate layer and a carbon coating layer coated on the surface of the aluminum foil substrate layer, wherein the carbon coating layer is obtained by coating and once curing a carbon coating layer composition for debonding carbon-coated aluminum foil as described in any one of the above items, and the temperature of the once curing is less than 130°C.

[0020] The temperature of the primary curing is controlled below 130°C, which can not only ensure the stable adhesion between the carbon coating layer and the aluminum foil substrate, but also prevent the high-temperature thermal curing agent in the carbon coating layer from being activated to produce secondary curing, which is beneficial to the normal use of the battery.

[0021] The present application provides a debonding method for a debonding carbon-coated aluminum foil, which specifically comprises the following steps: heating the debonding carbon-coated aluminum foil to a debonding temperature for secondary curing, wherein the debonding temperature is equal to or greater than the curing reaction temperature of the high-temperature thermal curing agent, so that the structure of the carbon-coated layer becomes brittle.

[0022] When the battery performance deteriorates and the positive electrode active material needs to be recovered, the debonded carbon-coated aluminum foil is directly heated to the debonding temperature. The debonding temperature is equal to or greater than the curing reaction temperature of the high-temperature thermal curing agent, which can activate the high-temperature thermal curing agent and promote the secondary curing of the carbon coating layer. The structure of the carbon coating layer becomes hard and brittle due to the secondary curing, which facilitates the peeling between the aluminum foil substrate and the positive electrode active material, and is conducive to obtaining a whole piece of positive electrode active material. There is no need for reduction and polymerization steps, which greatly simplifies the recycling process and saves recycling costs.

[0023] The present application provides an application of a debonding carbon-coated aluminum foil, which is specifically applied to the production of lithium-ion batteries.

[0024] In summary, this application at least includes the following beneficial technical effects: (1) The carbon coating composition of the present application uses both a low-temperature thermal curing agent and a high-temperature thermal curing agent. The low-temperature thermal curing agent is used to initiate primary curing, and the high-temperature thermal curing agent is used to initiate secondary curing. However, the initiation of primary curing is immediately after the application of the carbon coating composition, so as to promote the firm adhesion of the carbon coating layer to the surface of the aluminum foil substrate. The initiation of secondary curing is when the performance of the battery deteriorates after repeated use and the positive electrode active material needs to be recovered. The function of the secondary curing is to embrittle the carbon coating layer between the aluminum foil substrate and the positive electrode active material, thereby facilitating the peeling between the aluminum foil substrate and the positive electrode active material, which is beneficial to obtaining a whole piece of positive electrode active material without the need for reduction and polymerization steps, greatly simplifying the recycling process and saving recycling costs.

[0025] (2) In the present application, the debonding aid also includes a lithium compound. The lithium compound adopts a strong alkaline compound of lithium or a strong base weak acid salt of lithium, which can catalyze the high-temperature thermal curing agent to carry out a secondary curing reaction, which is beneficial to improve the reaction efficiency of the secondary curing and shorten the reaction time of the secondary curing. DETAILED DESCRIPTION

[0026] The present application is further described below in conjunction with specific experiments.

[0027] First, the present application discloses a debonding carbon-coated aluminum foil, comprising an aluminum foil substrate layer and a carbon-coated layer coated on the surface of the aluminum foil substrate layer, wherein the carbon-coated layer is obtained by coating and once-curing a carbon-coated layer composition for debonding carbon-coated aluminum foil.

[0028] Specifically, the carbon coating composition includes a conductive agent, a binder, a dispersant, an adhesion promoter, a low-temperature thermal curing agent and a debonding agent. The weight proportion of the conductive agent is 40~80%, the weight proportion of the binder is 15~50%, the weight proportion of the dispersant is 2~5%, the weight proportion of the adhesion promoter is 0.1~2%, the weight proportion of the low-temperature thermal curing agent is 2~5%, and the weight proportion of the debonding agent is 0.1~2%.

[0029] The conductive agent is a combination of any two or three of graphite, conductive carbon, and carbon nanotubes. The D50 particle size of the graphite is in the range of 2 to 20 μm, the particle size of the conductive carbon is in the range of 20 to 50 nm, and the carbon nanotubes are multi-walled carbon nanotubes. Preferably, a pretreatment step is added to the graphite, and the pretreatment step of the graphite is as follows: use a sand mill to peel the graphite, and the sand mill speed is 400 to 800 rpm until the viscosity stabilizes at 800 to 2500 cps, which is conducive to the uniform dispersion of the graphite. Further preferably, the conductive agent is a combination of graphite, conductive carbon, and multi-walled carbon nanotubes, and the weight ratio of graphite, conductive carbon, and multi-walled carbon nanotubes is (1-3): (1-2): 1.

[0030] The binder is any one of polyacrylic acid and polyethylene acrylic acid. Preferably, the glass transition temperature of polyacrylic acid is 100-150°C, and preferably, the glass transition temperature of polyethylene acrylic acid is 120-180°C.

[0031] The dispersant is used to improve the dispersing effect of the conductive agent in the binder, and the dispersant can be a polyacrylic acid dispersant or carboxymethyl cellulose.

[0032] The adhesion promoter is used to further improve the adhesion strength between the carbon coating layer and the aluminum foil substrate, wherein the adhesion promoter is at least one of a silane coupling agent, a tetrafunctional adhesion promoter, and a polyether-modified acrylate.

[0033] The low temperature heat curing agent is used for the primary curing of the carbon coating composition to achieve the firm adhesion of the carbon coating layer on the surface of the aluminum foil substrate. In the present application, the low temperature heat curing agent adopts amino resin or dicyandiamide or hydrazide, as long as the curing reaction temperature is lower than 130°C.

[0034] The debonding aid includes a high-temperature thermal curing agent, and the curing reaction temperature of the high-temperature thermal curing agent is greater than the curing reaction temperature of the low-temperature thermal curing agent. In the present application, the high-temperature thermal curing agent preferably uses a dicyandiamide-type high-temperature thermal curing agent with a curing reaction temperature greater than 150°C. By increasing the difference between the curing reaction temperatures of the high-temperature thermal curing agent and the low-temperature thermal curing agent, it is helpful to prevent the problem of partial reaction of the high-temperature thermal curing agent during the primary curing reaction process, and can further improve the bonding force between the carbon coating layer and the aluminum foil substrate.

[0035] Preferably, the debonding aid may also include a lithium compound, which is used to catalyze the secondary curing of the binder under the action of a high-temperature thermal curing agent. The lithium compound is a strong alkaline compound of lithium or a strong base weak acid salt of lithium.

[0036] That is, the carbon-coated layer composition of the present application uses both a low-temperature thermal curing agent and a high-temperature thermal curing agent. The low-temperature thermal curing agent is used to initiate primary curing, and the high-temperature thermal curing agent is used to initiate secondary curing. However, the primary curing is initiated immediately after the carbon-coated layer composition is applied, and the secondary curing is initiated when the battery performance deteriorates after repeated use and the positive electrode active material needs to be recovered.

[0037] The present application discloses a method for preparing a debonding carbon-coated aluminum foil, comprising the following steps: (1) Preparation of carbon-coated layer composition for debonding carbon-coated aluminum foil: S1. After uniformly mixing the conductive agent and the diluted dispersant by high-speed shearing, the pH value is adjusted to 6.5-7.5 to obtain a carbon source; wherein the dispersant is diluted with water, and the weight ratio of the dispersant to water is 1: (4-9); S2. Adjust the pH of the binder to 6.5-7.5, then add the carbon source and stir evenly to obtain a masterbatch; S3, adding the diluted adhesion promoter to the masterbatch, stirring evenly, to obtain a premix; in this step, the adhesion promoter is diluted with an ether alcohol diluent; S4, controlling the temperature of the premix at 10-35° C., then adding a debonding aid, and stirring evenly to obtain a debonding carbon-coated aluminum foil carbon-coated layer composition; Regarding the addition of low-temperature thermal curing agent, when the curing reaction temperature of the low-temperature thermal curing agent is lower than 60°C, it can be added to the carbon coating composition before coating and stirred evenly; when the curing reaction temperature of the low-temperature thermal curing agent is above 60°C, it can be diluted with an alcohol ether diluent and directly mixed in step S3 or S4.

[0038] Coating and primary curing: The carbon coating layer composition for the debonding carbon-coated aluminum foil is coated on the aluminum foil substrate by gravure coating, and the oven temperature is controlled not to exceed 130° C. for primary curing to obtain the debonding carbon-coated aluminum foil.

[0039] Preferably, in S1, a sand mill is used to exfoliate graphite, the sand mill speed is 400rpm, and the graphite is sanded to D50 = 2~20μm and the viscosity is 800~2500cps to obtain A slurry; the conductive carbon and carbon nanotubes are added to the dispersant diluted with water, the weight ratio of the dispersant to water is 1: (4-9), the pH is adjusted to 6.5~7.5, and then stirred to obtain B slurry, and then the A slurry and the B slurry are added to the sand mill for high shear mixing until the viscosity is 20~200cps to obtain a carbon source. According to this step, the carbon source is configured to facilitate the uniform dispersion of the conductive agent.

[0040] Preferably, the weight ratio of the adhesion promoter to the alcohol ether diluent is 1:(4-10), and the weight ratio of the low-temperature thermal curing agent to propylene glycol methyl ether is 1:(8-15).

[0041] The present application discloses a debonding method for a debonding carbon-coated aluminum foil, comprising the following steps: heating the debonding carbon-coated aluminum foil to a debonding temperature for secondary curing, wherein the debonding temperature is equal to or greater than a curing starting reaction temperature of a high-temperature thermal curing agent, so that the structure of the carbon-coated layer becomes brittle.

[0042] The present application is further described below in conjunction with specific experiments. Example

[0043] [Example 1] A debonding carbon-coated aluminum foil comprises an aluminum foil substrate layer and a carbon-coated layer coated on the surface of the aluminum foil substrate layer, wherein the carbon-coated layer is obtained by coating and curing a carbon-coated layer composition for debonding carbon-coated aluminum foil. In this embodiment, the carbon-coated layer composition for debonding carbon-coated aluminum foil is prepared from 40wt% of a conductive agent, 50% of a binder, 2wt% of a dispersant, 1.1wt% of an adhesion promoter, 5wt% of a low-temperature thermal curing agent, and 1.9wt% of a debonding aid. The conductive agent comprises graphite, acetylene black, and multi-walled carbon nanotubes, and the weight ratio of graphite, acetylene black, and multi-walled carbon nanotubes is 2:1:1; the binder is polyacrylic acid with a glass transition temperature of 120-125°C, the dispersant is a polyacrylic acid dispersant, the adhesion promoter is aminosilane coupling agent KH550, the low-temperature thermal curing agent is benzoyl hydrazide, and the debonding aid is a dicyandiamide high-temperature thermal curing agent DICY.

[0044] The present embodiment provides a method for preparing a debonding carbon-coated aluminum foil, comprising the following steps: (1) Preparation of carbon-coated layer composition for debonding carbon-coated aluminum foil: S1. Use a sand mill to exfoliate graphite at a speed of 400 rpm, sand mill to D50 = 8 μm, viscosity of 1700 ~ 2500 cps, to obtain A slurry; add acetylene black and multi-walled carbon nanotubes to a polyacrylic acid dispersant diluted with water (the ratio of dispersant to water is 1:6), adjust the pH to 6.5 ~ 7.5, and then stir to obtain B slurry, then add A slurry and B slurry into a sand mill for high shear mixing until the viscosity is 100 ~ 120 cps, to obtain a carbon source; S2, adjusting the pH of the binder polyacrylic acid to 6.5-7.5, then adding a carbon source and stirring evenly to obtain a masterbatch; S3, add the diluted aminosilane coupling agent KH550 and benzohydrazide to the masterbatch, stir evenly, and obtain a premix; in this step, the aminosilane coupling agent KH550 and benzohydrazide are both diluted with propylene glycol methyl ether, the weight ratio of the aminosilane coupling agent KH550 to propylene glycol methyl ether is 1:8, and the weight ratio of benzohydrazide to propylene glycol methyl ether is 1:10; S4, controlling the temperature of the premix at 25° C., then adding a dicyandiamide-based high-temperature heat curing agent DICY, and stirring evenly to obtain a carbon-coated layer composition for a debonding carbon-coated aluminum foil; (2) Coating and primary curing: The carbon coating layer composition for the debonding carbon-coated aluminum foil is coated on the aluminum foil substrate by gravure coating, and the oven temperature is controlled to be 125° C. for primary curing, and the curing time is 60 seconds to obtain the debonding carbon-coated aluminum foil.

[0045] [Example 2] A debonding carbon-coated aluminum foil, which differs from [Example 1] in that the weight proportions of the components of the carbon-coated layer composition used for the debonding carbon-coated aluminum foil are different.

[0046] In this embodiment, the carbon coating layer composition for debonding carbon-coated aluminum foil is prepared from 75wt% of a conductive agent, 15% of a binder, 5wt% of a dispersant, 0.1wt% of an adhesion promoter, 3wt% of a low-temperature thermal curing agent, and 1.9wt% of a debonding aid.

[0047] Performance testing The peel strength test was performed on the debonding carbon-coated aluminum foil prepared in the above-mentioned Examples 1 and 2. Then, the debonding carbon-coated aluminum foil prepared in the above-mentioned Examples 1 and 2 was heated to 200° C. for secondary curing. The secondary curing time was 60 seconds. After cooling, the peel strength between the carbon-coated layer in the debonding carbon-coated aluminum foil and the aluminum foil substrate was tested again.

[0048] Table 1

[0049] Combining the contents of the above-mentioned Example 1 and Example 2, it can be known that before debonding, the peeling strength between the carbon-coated layer and the aluminum foil substrate in the debonded carbon-coated aluminum foil is greater than 3N / cm, and after debonding, the peeling strength between the carbon-coated layer and the aluminum foil substrate in the debonded carbon-coated aluminum foil is less than 1N / cm. Among them, after debonding, the structure of the debonded carbon-coated aluminum foil becomes brittle, which greatly reduces the peeling strength between the carbon-coated layer and the aluminum foil substrate, which is conducive to the peeling of the carbon-coated layer and the aluminum foil substrate, and at the same time, it is also conducive to the peeling between the carbon-coated layer and the positive electrode active material, so that the positive electrode active material can be recovered in one piece.

[0050] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A carbon-coated layer composition for debonding carbon-coated aluminum foil, characterized in that: It includes a basic carbon-coated raw material, a low-temperature thermal curing agent and a debonding aid, wherein the debonding aid includes a high-temperature thermal curing agent, the curing reaction temperature of the low-temperature thermal curing agent is less than 130°C, and the curing starting reaction temperature of the high-temperature thermal curing agent is greater than the curing reaction temperature of the low-temperature curing agent.

2. The carbon-coated layer composition for debonding carbon-coated aluminum foil according to claim 1, characterized in that: The debonding aid further comprises a lithium compound, and the lithium compound is a strong alkaline compound of lithium or a strong base weak acid salt of lithium.

3. A carbon-coated layer composition for debonding carbon-coated aluminum foil according to claim 1 or 2, characterized in that: The basic carbon-coated raw material includes a conductive agent, a binder, a dispersant and an adhesion promoter; in the carbon-coated layer composition for the debonding carbon-coated aluminum foil, the weight proportion of the conductive agent is 40-80%, the weight proportion of the binder is 15-50%, the weight proportion of the dispersant is 2-5%, the weight proportion of the adhesion promoter is 0.1-2%, the weight proportion of the low-temperature thermal curing agent is 2-5%, and the weight proportion of the debonding aid is 0.1-2%.

4. The carbon-coated layer composition for debonding carbon-coated aluminum foil according to claim 3, characterized in that: The conductive agent is a combination of any two or three of graphite, conductive carbon and carbon nanotubes, wherein the D50 particle size of the graphite is in the range of 2-20 μm, the particle size of the conductive carbon is in the range of 20-50 nm, and the carbon nanotubes are multi-walled carbon nanotubes.

5. The carbon-coated layer composition for debonding carbon-coated aluminum foil according to claim 3, characterized in that: The adhesive is any one of polyacrylic acid and polyethylene acrylic acid, wherein the glass transition temperature of the polyacrylic acid is 100-150°C, and the glass transition temperature of the polyethylene acrylic acid is 120-180°C.

6. The carbon-coated layer composition for debonding carbon-coated aluminum foil according to claim 3, characterized in that: The adhesion promoter is at least one of a silane coupling agent, a tetrafunctional adhesion promoter, and a polyether-modified acrylate.

7. A method for preparing a carbon-coated layer composition for debonding carbon-coated aluminum foil according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. After uniformly mixing the conductive agent and the diluted dispersant by high-speed shearing, the pH value is adjusted to 6.5-7.5 to obtain a carbon source; wherein the dispersant is diluted with water; S2. Adjust the pH of the binder to 6.5-7.5, then add the carbon source, stir evenly, and obtain a masterbatch; S3, adding the diluted adhesion promoter to the masterbatch, stirring evenly, to obtain a premix; in this step, the adhesion promoter is diluted with an ether alcohol diluent; S4, controlling the temperature of the premix at 10-35° C., then adding a debonding aid, and stirring evenly to obtain a debonding carbon-coated aluminum foil carbon-coated layer composition; Regarding the addition of a low-temperature thermal curing agent, when the curing reaction temperature of the low-temperature thermal curing agent is lower than 60°C, it can be added to the carbon coating composition before coating and stirred evenly; when the curing reaction temperature of the low-temperature thermal curing agent is above 60°C, it can be diluted with an alcohol ether diluent and directly mixed in step S3 or S4.

8. A debonding carbon-coated aluminum foil, characterized in that: The invention comprises an aluminum foil substrate layer and a carbon coating layer coated on the surface of the aluminum foil substrate layer, wherein the carbon coating layer is obtained by coating and once curing a carbon coating layer composition for debonding carbon-coated aluminum foil according to any one of claims 1 to 6, and the temperature of the once curing is less than 130°C.

9. A debonding method for debonding carbon-coated aluminum foil as claimed in claim 8, characterized in that: The following steps are involved: The debonding carbon-coated aluminum foil is heated to a debonding temperature for secondary curing, wherein the debonding temperature is equal to or greater than the curing reaction temperature of the high-temperature thermal curing agent, so that the structure of the carbon-coated layer becomes brittle.

10. An application of the debonding carbon-coated aluminum foil as claimed in claim 8, characterized in that: Used in the production of lithium-ion batteries.

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