Highly conductive nanocoated current collector, electrode, battery, and method for manufacturing the current collector.

Abstract

This application relates to the field of electrode materials, specifically to a highly conductive nanocoated current collector, an electrode, a battery, and a method for manufacturing the current collector. The highly conductive nanocoated current collector comprises a current collector and nanoconductive coating layers applied to both sides thereof, wherein the nanoconductive coating layers contain a graphene oxide graft adhesive. The method for manufacturing the highly conductive nanocoated current collector includes step 1 of preparing a graphene oxide graft adhesive, step 2 of preparing a coating paste containing the graphene oxide graft adhesive, and step 3 of applying the coating paste to at least one side of the current collector, drying it, and then manufacturing the coated current collector. This application provides a certain conductivity to the adhesive itself by adding a graphene oxide graft adhesive to the coating layer, thereby bonding the conductive material and the current collector without affecting the overall conductive effect of the electrode.

Description

Technical Field

[0001] This application relates to the field of electrode materials, and particularly to a highly conductive nano-coated current collector, an electrode, a battery, and a method for manufacturing this current collector.

Background Art

[0002] Lithium-ion batteries have already been widely used in fields such as consumer electronics and electric vehicles. In the market, higher requirements have also been put forward for aspects such as the energy density, cycle life, and usage safety of lithium-ion batteries. The current collector conductive undercoating technology can effectively reduce the contact resistance between the electrode material and the current collector, increase the adhesion force between the electrode material and the current collector, reduce the internal resistance of the battery, and extend the life of the battery.

[0003] However, for a nano-conductive coating current collector, a certain amount of adhesive needs to be used in the manufacturing process. The adhesive itself does not have conductivity. If the addition amount is too much, the conductive performance of the nano-conductive coating layer will decrease. If the addition amount is too little, the conductive material cannot be adhered well. At the same time, a too thick nano-conductive coating layer also affects the conductive effect of the entire electrode and suppresses the ability of the nano-conductive coating layer to further improve the conductive performance of an electrode with a poor conductive electrode material.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The following is a summary of the subject matter to be described in detail in this specification. This summary is not intended to limit the scope of the claims.

[0005] In order to overcome the problems existing in the prior art, this application provides a highly conductive nano-coated current collector, an electrode, a battery, and a method for manufacturing this current collector.

Means for Solving the Problems

[0006] The present invention relates to a highly conductive nanocoated current collector, electrode, battery, and a method for manufacturing the current collector, and incorporates the following technical considerations.

[0007] A highly conductive nanocoated current collector comprising a current collector and nanoconductive coating layers applied to both sides thereof, wherein the nanoconductive coating layers contain a graphene oxide graft adhesive.

[0008] By adopting the above technical proposal, graphene oxide graft adhesive is added to the coating layer, giving the adhesive itself a certain degree of conductivity, thereby bonding the conductive material and the current collector without affecting the overall conductive effect of the electrode.

[0009] Graphene oxide adhesive is synthesized by reacting polyisocyanate with graphene oxide, and then polymerizing the modified intermediate, which is obtained by reacting the synthesized material with hydroxyacrylic acid, with the adhesive monomer. Graphene oxide is an oxide of graphene, has a yellowish-brown color, and is commonly found in the market as a powder, sheet, and solution. After oxidation, its oxygen-containing functional groups increase, making it more active than graphene, and its properties can be improved through various reactions with oxygen-containing functional groups.

[0010] The nanoconductive coating layer comprises a solution and a conductive material dispersed in the solution, along with a graphene oxide graft adhesive.

[0011] A method for manufacturing a highly conductive nanocoated current collector, comprising: step 1 preparing a graphene oxide graft adhesive; step 2 preparing a coating paste containing the graphene oxide graft adhesive; and step 3 applying the coating paste to at least one surface of a current collector, drying it, and then manufacturing a coated current collector.

[0012] Preferably, the method for preparing the graphene oxide graft adhesive in step 1 includes first uniformly mixing polyisocyanate and graphene oxide in ethyl acetate, which is a solvent, filtering the mixture after the reaction is complete, and reacting the synthesized product with hydroxyacrylate to prepare a modified intermediate, and then polymerizing the modified intermediate with an adhesive monomer and adding a graft initiator to synthesize the graphene oxide graft adhesive.

[0013] The reaction equation for mixing polyisocyanate with graphene oxide and reacting it with ethyl hydroxyacrylate to produce a modified intermediate is as follows: [ka]

[0014] By adopting the above technical proposal, one isocyanate group of polyisocyanate reacts with a hydroxyl or carboxyl group of graphene oxide, and the other isocyanate group reacts with a hydroxyl group of hydroxyacrylic acid, retaining the double bond in hydroxyacrylic acid, thereby linking graphene oxide and hydroxyacrylate to form a modified intermediate. The graphene oxide graft adhesive formed by polymerizing the modified intermediate with an adhesive monomer has adhesive properties and a certain degree of conductivity. Conventional adhesive layers have poor conductivity and high resistance during the battery's operation. By polymerizing the prepared modified intermediate with an acrylic acid monomer adhesive to graft-synthesize a graphene oxide adhesive, and adding the graphene oxide adhesive on a conductive material in the same ratio as the adhesive, a nano-conductive coating layer can be made to have better conductivity and lower resistance.

[0015] Preferably, the polyisocyanate is one or more of aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates.

[0016] By adopting the above technical proposal, polyisocyanates are one of the main raw materials for polyurethane adhesives and include aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates. Aliphatic isocyanates have a chain structure, and the acrylates that react with them also have a chain structure, allowing them to react more easily. Furthermore, compared to the rigid cyclic structures of aromatic and alicyclic isocyanates, the chain structure of aliphatic isocyanates has better flexibility, is less prone to yellowing, and exhibits good anti-aging properties.

[0017] Preferably, the mass ratio of the modified intermediate to the adhesive monomer is 1:10 to 100.

[0018] Preferably, the adhesive monomer is an acrylic acid monomer and includes one or more of acrylic acid, methyl methacrylate, butyl acrylate, isobutyl acrylate, methacrylic acid, and its derivatives.

[0019] Conventionally, mixing and contacting graphene oxide with acrylic acid-based adhesives only allows for synergistic action, but it cannot perform the role of chemical bonding. By adopting the above technical proposal, the modified intermediate formed by linking graphene oxide and hydroxyacrylate has a double bond, enabling chemical bonding between graphene oxide and acrylic acid-based monomers, and completing the polymerization of the modified intermediate and adhesive monomers.

[0020] Preferably, a persulfate compound is used as the graft initiator, the graft reaction temperature is 50-80°C, the reaction time is 5-10 hours, and the solid content of the graphene oxide graft adhesive is 20-30%.

[0021] Preferably, the method for preparing the highly conductive nanocoating paste in step 2 is to mix a conductive material, a graphene oxide graft adhesive, and a solvent in a certain ratio, stir and disperse for 2 to 10 hours to prepare the highly conductive nanocoating paste. The mass ratio of the conductive material to the graphene oxide graft adhesive is 1:0.5 to 1.5, and the solid content of the highly conductive nanocoating material is 5 to 10%. The conductive material is one or more of conductive carbon black, conductive graphite, carbon nanotubes, and graphene, and the solvent is water.

[0022] An electrode including the above-described highly conductive nanocoating current collector.

[0023] A battery including the above-described electrode.

Advantages of the Invention

[0024] In short, the present application includes at least one of the following technical effects.

[0025] 1. In the present application, by grafting graphene oxide onto an adhesive molecule through a polymerization reaction to endow the adhesive itself with certain conductivity, the conductive material and the current collector are adhered by a nano-conductive coating layer without affecting the conductive effect of the entire electrode.

[0026] After reading and understanding the detailed description, other points can be understood.

Brief Description of the Drawings

[0027] The drawings are used to provide a further understanding of the technical solutions of this specification, constitute a part of the specification, and are used together with the embodiments of the present application to interpret the technical solutions of the specification, and do not limit the technical solutions of the specification.

[0028] [Figure 1] It is a schematic structural diagram of a highly conductive nanocoating current collector layer.

Modes for Carrying out the Invention

[0029] The present application will be explained in more detail below, in conjunction with Figure 1.

[0030] The embodiments of this application disclose a highly conductive nanocoated current collector, an electrode, a battery, and a method for manufacturing the current collector.

[0031] (Example 1) A highly conductive nanocoated current collector comprises a current collector 1 and nanoconductive coating layers 2 applied to both sides thereof, wherein the nanoconductive coating layers 2 contain a graphene oxide graft adhesive. By adding the graphene oxide graft adhesive to the coating layer, the adhesive itself is given a certain degree of conductivity, thereby bonding the conductive material and the current collector without affecting the overall conductive effect of the electrode.

[0032] The graphene oxide adhesive is synthesized by reacting polyisocyanate with graphene oxide, and then polymerizing the modified intermediate, which is obtained by reacting the synthesized product with hydroxyacrylic acid, with the adhesive monomer.

[0033] The nanoconductive coating layer comprises a solution and a conductive material dispersed in the solution, along with a graphene oxide graft adhesive.

[0034] A method for manufacturing a highly conductive nanocoated current collector includes the following steps.

[0035] Step 1: 1 kg of isophorone diisocyanate and 0.5 kg of graphene oxide were homogeneously mixed in butyl acetate, which was used as the solvent. After the reaction was complete, the mixture was filtered and further reacted with 0.5 kg of hydroxyethyl acrylate to prepare a modified intermediate. Then, 1 kg of the modified intermediate was dissolved in 10 kg of acrylic acid and slowly added dropwise to the reaction vessel to carry out emulsion polymerization. The reaction temperature was 70°C and the reaction time was 8 hours. Persulfate compounds were added to obtain a graphene oxide graft adhesive emulsion, and the solids content was adjusted to 25%.

[0036] Step 2: 10 kg of conductive carbon black, 20 kg of prepared graphene oxide graft adhesive emulsion, and 157.5 kg of water were mixed and dispersed for 4 hours to prepare a highly conductive nanocoating paste with a solid content of 8%.

[0037] Step 3: Using a coating machine, a highly conductive nanocoating paste was applied to both sides of a 13 μm aluminum current collector to a thickness of 1 μm, and then dried to obtain a highly conductive nanocoated current collector.

[0038] An electrode containing the highly conductive nanocoated current collector described above.

[0039] A battery containing the electrodes described above.

[0040] (Example 2) The highly conductive nanocoated current collector, electrodes, and battery are the same as in Example 1, except that the only difference is the method for manufacturing the highly conductive nanocoated current collector, which includes the following steps.

[0041] Step 1: 1 kg of isophorone diisocyanate and 0.5 kg of graphene oxide were homogeneously mixed in butyl acetate, which was used as the solvent. After the reaction was complete, the mixture was filtered and further reacted with 0.5 kg of hydroxyethyl acrylate to prepare a modified intermediate. Then, 1 kg of the modified intermediate was dissolved in 50 kg of acrylic acid and slowly added dropwise to a reaction vessel to carry out emulsion polymerization. The reaction temperature was 50°C and the reaction time was 8 hours. A persulfate compound was added to obtain a graphene oxide graft adhesive emulsion, and the solids content was adjusted to 25%.

[0042] Step 2: 10 kg of conductive carbon black, 40 kg of prepared graphene oxide graft adhesive emulsion, and 200 kg of water were mixed and dispersed for 6 hours to prepare a highly conductive nanocoating paste with a solids content of 8%.

[0043] Step 3: Using a coating machine, a highly conductive nanocoating paste was applied to both sides of a 13 μm aluminum current collector to a thickness of 1 μm, and then dried to obtain a highly conductive nanocoated current collector.

[0044] (Example 3) The highly conductive nanocoated current collector, electrodes, and battery are the same as in Example 1, except that the only difference is the method for manufacturing the highly conductive nanocoated current collector, which includes the following steps.

[0045] Step 1: 1 kg of isophorone diisocyanate and 0.5 kg of graphene oxide were homogeneously mixed in butyl acetate, which was used as the solvent. After the reaction was complete, the mixture was filtered and further reacted with 0.5 kg of hydroxyethyl acrylate to prepare a modified intermediate. Then, 1 kg of the modified intermediate was dissolved in 80 kg of acrylic acid and slowly added dropwise to a reaction vessel to carry out emulsion polymerization. The reaction temperature was 80°C and the reaction time was 5 hours. A persulfate compound was added to obtain a graphene oxide graft adhesive emulsion, and the solids content was adjusted to 25%.

[0046] Step 2: 10 kg of conductive carbon black, 40 kg of prepared graphene oxide graft adhesive emulsion, and 200 kg of water were mixed and dispersed for 6 hours to prepare a highly conductive nanocoating paste with a solids content of 8%.

[0047] Step 3: Using a coating machine, a highly conductive nanocoating paste was applied to both sides of a 13 μm aluminum current collector to a thickness of 1 μm, and then dried to obtain a highly conductive nanocoated current collector.

[0048] (Example 4) The highly conductive nanocoated current collector, electrodes, and battery are the same as in Example 1, except that the only difference is the method for manufacturing the highly conductive nanocoated current collector, which includes the following steps.

[0049] Step 1: 1 kg of isophorone diisocyanate and 0.5 kg of graphene oxide were homogeneously mixed in butyl acetate, which was used as the solvent. After the reaction was complete, the mixture was filtered and further reacted with 0.5 kg of hydroxyethyl acrylate to prepare a modified intermediate. Then, 1 kg of the modified intermediate was dissolved in 80 kg of acrylic acid and slowly added dropwise to a reaction vessel to carry out emulsion polymerization. The reaction temperature was 70°C and the reaction time was 6 hours. Persulfate compounds were added to obtain a graphene oxide graft adhesive emulsion, and the solids content was adjusted to 25%.

[0050] Step 2: 10 kg of conductive carbon black, 60 kg of prepared graphene oxide graft adhesive emulsion, and 242.5 kg of water were mixed and dispersed for 8 hours to prepare a highly conductive nanocoating paste with a solid content of 8%.

[0051] Step 3: Using a coating machine, a highly conductive nanocoating paste was applied to both sides of a 13 μm aluminum current collector to a thickness of 1 μm, and then dried to obtain a highly conductive nanocoated current collector.

[0052] (Example 5) The highly conductive nanocoated current collector, electrodes, and battery are the same as in Example 1, except that the only difference is the method for manufacturing the highly conductive nanocoated current collector, which includes the following steps.

[0053] Step 1: 1 kg of isophorone diisocyanate and 0.5 kg of graphene oxide were homogeneously mixed in butyl acetate, which was used as the solvent. After the reaction was complete, the mixture was filtered and further reacted with 0.5 kg of hydroxyethyl acrylate to prepare a modified intermediate. Then, 1 kg of the modified intermediate was dissolved in 100 kg of acrylic acid and slowly added dropwise to a reaction vessel to carry out emulsion polymerization. The reaction temperature was 60°C and the reaction time was 5 hours. A graft initiator was added to obtain a graphene oxide graft adhesive emulsion, and the solids content was adjusted to 25%.

[0054] Step 2: 10 kg of conductive carbon black, 40 kg of prepared graphene oxide graft adhesive emulsion, and 200 kg of water were mixed and dispersed for 8 hours to prepare a highly conductive nanocoating paste with a solid content of 8%.

[0055] Step 3: Using a coating machine, a highly conductive nanocoating paste was applied to both sides of a 13 μm aluminum current collector to a thickness of 1 μm, and then dried to obtain a highly conductive nanocoated current collector.

[0056] The above are all preferred embodiments of the present application and do not limit the scope of protection. Therefore, equivalent modifications based on the structure, shape, and principle of the present application should all be included within the scope of protection.

[0057] (Comparative Example 1) The highly conductive nanocoated current collector, electrodes, and battery are the same as in Example 1, but the only difference in the manufacturing method of the highly conductive nanocoated current collector from Example 1 is that a conductive polymer graft is not used in step 1, and in step 2, a highly conductive nanocoating paste is prepared by mixing a polyacrylic acid (PAA) aqueous solution with a solid content of 25% with conductive carbon black.

[0058] (Comparative Example 2) The highly conductive nanocoated current collector, electrodes, and battery are the same as in Example 2, but the only difference in the manufacturing method of the highly conductive nanocoated current collector from Example 2 is that in step 2, 10 kg of conductive carbon black is replaced with a mixture of 9.5 kg of conductive carbon black and 0.5 kg of carbon nanotubes.

[0059] (Comparative Example 3) The highly conductive nanocoated current collector, electrodes, and battery are the same as in Example 3, but the only difference in the manufacturing method of the highly conductive nanocoated current collector from Example 3 is that the stirring and dispersion time in step 2 is set to 10 hours.

[0060] Performance testing of highly conductive nanocoated current collectors. The highly conductive nanocoated current collectors manufactured in Examples 1-5 and Comparative Examples 1-3 were tested for sheet resistance and through-wall resistance according to the following method. The test results are shown in the table below.

[0061] (1) Sheet resistance: Measured using a 4-probe resistor (probe type, total pressure stroke).

[0062] (2) Through-pass resistance: Measured with a pole-piece resistor. The highly conductive nano-coated current collectors manufactured in each example and comparative example were cut into approximately 5cm x 5cm squares, placed under the measuring head, and held at a measuring pressure of 0.3t for 5s. [Table 1]

[0063] As shown in the test results, Example 1 is the optimal example, and the sheet resistance and through-sheet resistance of the manufactured highly conductive nanocoated current collector were the lowest. This verifies that grafting graphene oxide onto adhesive molecules and applying it to the nanoconductive coating layer can provide a good conductive effect. [Explanation of symbols]

[0064] 1...Current collector; 2...Nano conductive coating layer.

Claims

1. A highly conductive nanocoated current collector comprising a current collector (1) and a nanoconductive coating layer (2) applied to both sides thereof, The nano-conductive coating layer (2) contains a graphene oxide graft adhesive. Highly conductive nano-coated current collector.

2. The aforementioned graphene oxide adhesive is synthesized by reacting polyisocyanate with graphene oxide, and then polymerizing the modified intermediate obtained by reacting the synthesized product with hydroxyacrylic acid with the adhesive monomer. The highly conductive nanocoated current collector according to claim 1.

3. The nanoconductive coating layer comprises a solution, and a conductive material dispersed in the solution and a graphene oxide graft adhesive. A highly conductive nanocoated current collector according to claim 1 or 2.

4. Step 1 involves preparing a graphene oxide graft adhesive, Step 2 involves preparing a coating paste containing the graphene oxide graft adhesive, The process includes step 3, which involves applying a coating paste to at least one surface of a current collector, allowing it to dry, and then manufacturing a coated current collector. A method for manufacturing a highly conductive nanocoated current collector.

5. The method for preparing the graphene oxide graft adhesive in step 1 includes: first, uniformly mixing polyisocyanate and graphene oxide in ethyl acetate, which is a solvent; filtering the mixture after the reaction is complete; reacting the synthesized product with hydroxyacrylate to prepare a modified intermediate; and polymerizing the modified intermediate with an adhesive monomer, adding a graft initiator, and synthesizing the graphene oxide graft adhesive. A method for manufacturing a highly conductive nanocoated current collector according to claim 4.

6. The isocyanate is one or more of aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates. A method for manufacturing a highly conductive nanocoated current collector according to claim 5.

7. The mass ratio of the modified intermediate to the adhesive monomer is 1:10 to 100. A method for manufacturing a highly conductive nanocoated current collector according to claim 5 or 6.

8. The adhesive monomer is an acrylic acid monomer and includes one or more of acrylic acid, methyl methacrylate, butyl acrylate, isobutyl acrylate, methacrylic acid, and its derivatives. A method for manufacturing a highly conductive nanocoated current collector according to any one of claims 5 to 7.

9. The graft initiator is a persulfate compound, the graft reaction temperature is 50 to 80°C, the reaction time is 5 to 10 hours, and the solid content of the graphene oxide graft adhesive is 20 to 30%. A method for manufacturing a highly conductive nanocoated current collector according to any one of claims 5 to 8.

10. The method for preparing the coating paste in step 2 involves mixing a conductive material, a graphene oxide graft adhesive, and a solvent in a fixed ratio, stirring and dispersing them for 2 to 10 hours, and preparing a highly conductive nanocoating paste. The mass ratio of the conductive material to the graphene oxide graft adhesive is 1:0.5 to 1.5, the solid content of the material of the highly conductive nanocoating is 5 to 10%, the conductive material is one or more of conductive carbon black, conductive graphite, carbon nanotubes, and graphene, and the solvent is water. A method for manufacturing a highly conductive nanocoated current collector according to claim 4.

11. An electrode comprising a highly conductive nanocoated current collector according to any one of claims 1 to 3.

12. A battery comprising the electrode according to claim 11.

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