High-performance current collector and processing technology thereof

Abstract

The invention relates to the technical field of current collectors, and particularly discloses a high-performance current collector and a processing technology thereof.According to the high-performance current collector and the processing technology thereof, various materials with higher hardness are adopted to replace aluminum oxide to serve as a bottom layer of the current collector, so that the structure of the bottom layer is kept stable in the pole piece rolling process, and defects of the bottom layer are avoided; and the base membrane and the metal layer are separated under the soaking of the electrolyte, so that the performance of the battery is degraded. Meanwhile, maleic anhydride is grafted on the surface of the base film, so that the binding power of the polymer film is enhanced, the thermal stability and mechanical property of the polymer film are improved, and further processing of the polymer film is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of current collectors, and particularly to a high-performance current collector and its processing technology. Background Art

[0002] Currently, high-performance current collectors based on polymer films have received extensive attention and applications in the new energy industry. The preparation of such current collectors usually involves depositing a layer of metal on a polymer film (such as polyester, polyolefin, etc.) by physical vapor deposition (PVD) to produce a high-performance current collector with good conductivity. Compared with traditional current collectors, high-performance current collectors based on polymer films have the characteristics of low cost, light weight, and good internal insulation. These characteristics enable high-performance current collectors to reduce the cost of batteries, and improve the energy density and safety of batteries when applied in batteries.

[0003] Generally, in order to improve the adhesion between the base film and the metal layer in a high-performance current collector, an alumina primer layer is provided between the base film and the metal layer, or an additive - rigid particle silica is added to the base film. However, the strength of the alumina primer layer is low, and it is easy for silica to squeeze the primer layer during the pole piece rolling process, resulting in defects in it. Furthermore, it is prone to corrosion under the condition of being soaked in battery electrolyte, leading to the separation of the base film and the metal layer, and causing the attenuation of battery performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-performance current collector and its processing technology, which uses a primer layer material with high strength to replace the alumina primer layer, thereby avoiding the problems of defects in the primer layer during the pole piece rolling process and the delamination of the base film and the metal layer caused by this during electrolyte soaking, keeping the structure of the primer layer stable during the pole piece rolling process, and further realizing the structural stability of the metal layer and the base film during the battery cycle, and improving the performance of the battery.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A high-performance current collector includes a base film layer, primer layers provided on both side surfaces of the base film layer, a metal layer provided on the side of the primer layer away from the base film layer, and the material of the primer layer is one or a combination of silicon aluminum, silica-alumina mixture, aluminum nitride, aluminum nitride-alumina mixture, silicon carbide, silicon carbide-alumina mixture, zirconia-alumina mixture, nickel aluminum, nickel silicon, nickel chromium, nickel chromium aluminum.

[0007] As a limitation of the present invention, the molar ratio of silicon to aluminum in the silicon-aluminum is 1:(11-15), the molar ratio of silicon dioxide to aluminum oxide in the silicon dioxide-aluminum oxide mixture is 1:1, the molar ratio of aluminum nitride to aluminum oxide in the aluminum nitride-aluminum oxide mixture is 1:(0.5-2), the molar ratio of silicon carbide to aluminum oxide in the silicon carbide-aluminum oxide mixture is 1:(0.5-2), the molar ratio of zirconium oxide to aluminum oxide in the zirconium oxide-aluminum oxide mixture is 1:(0.4-0.8), the molar ratio of nickel to aluminum in the nickel-aluminum is 1:(0.5-1), the molar ratio of nickel to silicon in the nickel-silicon is 1:(0.2-0.5), the molar ratio of nickel to chromium in the nickel-chromium is 1:(0.2-0.5), and the molar ratio of nickel, chromium, and aluminum in the nickel-chromium-aluminum is 1:(0.5-1):(0.2-0.5).

[0008] As a limitation of the present invention, the material of the metal layer is one or more combinations of copper, aluminum, copper alloy, and aluminum alloy.

[0009] As a limitation of the present invention, the material of the protective layer is one or more combinations of nickel, chromium, nickel-based alloy, copper-based alloy, copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, graphite, carbon black, copper chromium oxide, carbon nano quantum dot, carbon nanotube, carbon nanofiber, and graphene.

[0010] As a limitation of the present invention, the thickness of the primer layer provided on either side of the base film is 1 nm to 50 nm, preferably 2 nm to 20 nm.

[0011] As a limitation of the present invention, the material of the base film layer is one or more combinations of polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyimide, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene ether, polystyrene, and polyamide.

[0012] As a limitation of the present invention, the high-performance current collector satisfies any one of the following conditions:

[0013] (1) The thickness of the base film layer of the current collector is 1 μm to 10 μm;

[0014] (2) The thickness of the metal layer of the current collector is 500 nm to 2000 nm;

[0015] (3) The thickness of the protective layer of the current collector is 2 nm to 100 nm, preferably 10 nm to 80 nm.

[0016] As a limitation of the present invention, the base film layer is a maleic anhydride-modified base film, and the preparation method is:

[0017] Dissolve maleic anhydride in deionized water and stir evenly to obtain a maleic anhydride solution. Dissolve styrene and benzoyl peroxide in xylene and stir evenly to obtain a styrene mixed solution. At 75-85 °C, immerse the base film in the mixed solution of the styrene mixed solution and the maleic anhydride solution, and then perform microwave irradiation treatment. Keep the temperature of the mixed solution at 75-85 °C, set the microwave power at 600-750 W, and the reaction time at 5-30 min. After the reaction is completed, take out the base film, rinse it with acetone, and dry it to obtain a maleic anhydride-modified base film.

[0018] A preparation method of a high-performance current collector, specifically:

[0019] Step 1: Magnetron sputter a bottom layer on the surface of the base film layer. The target used during magnetron sputtering is the bottom layer material. The argon flow rate during magnetron sputtering is 90-100 mL / min, the coating vacuum degree is 0.06-0.08 Pa, and the temperature of the main roller during the coating process is -10-0 °C;

[0020] Step 2: Vacuum deposit on the outer surface of the bottom layer. Melt and evaporate the metal layer material at a high temperature of 1200-1300 °C. The evaporated metal atoms are cooled and deposited on the outer surface of the bottom layer to form a metal layer.

[0021] An application of a high-performance current collector in a battery.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] The present invention uses a variety of materials with higher hardness to replace alumina as the bottom layer of the current collector, avoiding defects during the rolling process of the electrode sheet. The bottom layer maintains a stable structure during the rolling process of the electrode sheet, and thus realizes the structural stability of the metal layer and the base film during the battery cycling process, improving the performance of the battery.

[0024] The present invention modifies the polymer film with maleic anhydride, and prepares maleic anhydride grafted-polymer on the surface of the polymer film by microwave induction. At the same time, styrene is added as a second monomer to improve the grafting rate of maleic anhydride. After grafting maleic anhydride, the polarity of the polymer is enhanced, the adhesion of the polymer film is enhanced, molecular chain entanglement occurs between the polymer and maleic anhydride, improving the thermal stability and mechanical properties of the polymer film, which is beneficial to the further processing of the polymer film. Specific embodiments

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] PET film (thickness: 6 μm, tensile strength: >200 MPa, elongation at break: >40%).

[0027] Example 1: A processing technology for a high-performance current collector, specifically:

[0028] Step 1: Magnetron sputter nickel-aluminum on the surface of the PET film to prepare a PET film with an underlayer. The target used for magnetron sputtering is nickel-aluminum, with a purity >99.9%, a nickel-aluminum molar ratio of 2:1. The magnetron sputtering process parameters are an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process is -10°C, obtaining an underlayer thickness of 20 nm.

[0029] Step 2: Place the prepared PET film with an underlayer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with an underlayer, forming an aluminum metal layer with a thickness of 1 μm.

[0030] Step 3: After the evaporation is completed, take out the PET film with an aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, obtaining a high-performance current collector.

[0031] Example 2: A processing technology for a high-performance current collector, specifically:

[0032] Step 1: Magnetron sputter nickel-chromium on the surface of the PET film to prepare a PET film with an underlayer. The target used for magnetron sputtering is nickel-chromium, with a purity >99.9%, a nickel-chromium molar ratio of 2:1. The magnetron sputtering process parameters are an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process is -10°C, obtaining an underlayer thickness of 20 nm.

[0033] Step 2: Place the prepared PET film with an underlayer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with an underlayer, forming an aluminum metal layer with a thickness of 1 μm.

[0034] Step 3: After the evaporation is completed, take out the PET film with an aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, obtaining a high-performance current collector.

[0035] Example 3: A processing technology for a high-performance current collector, specifically:

[0036] Step 1: Magnetron sputter nickel-chromium-aluminum on the surface of a PET film to prepare a PET film with an underlayer. The target used during magnetron sputtering is nickel-chromium-aluminum, with a purity > 99.9%, a nickel-chromium-aluminum molar ratio of 2:1:1. The magnetron sputtering process parameters are an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process is -10°C. The thickness of the underlayer is 20 nm.

[0037] Step 2: Place the prepared PET film with an underlayer in the chamber of vacuum evaporation. Melt and evaporate high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with an underlayer, forming an aluminum metal layer with a thickness of 1 μm.

[0038] Step 3: After the evaporation is completed, take out the PET film with an aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so as to form an aluminum oxide protective layer with a thickness of 3 nm on the surface of the metal layer, and obtain a high-performance current collector.

[0039] Example 4: A processing technology for a high-performance current collector, specifically:

[0040] Step 1: Magnetron sputter a silica-alumina mixture on the surface of a PET film to prepare a PET film with an underlayer. The target used during magnetron sputtering is a silica-alumina mixture, with a silica-to-alumina molar ratio of 1:1. The magnetron sputtering process parameters are an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process is -10°C. The thickness of the underlayer is 20 nm.

[0041] Step 2: Place the prepared PET film with an underlayer in the chamber of vacuum evaporation. Melt and evaporate high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with an underlayer, forming an aluminum metal layer with a thickness of 1 μm.

[0042] Step 3: After the evaporation is completed, take out the PET film with an aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so as to form an aluminum oxide protective layer with a thickness of 3 nm on the surface of the metal layer, and obtain a high-performance current collector.

[0043] Example 5: A processing technology for a high-performance current collector, specifically:

[0044] Step 1: Magnetron sputter a silicon carbide-aluminum oxide mixture on the surface of the PET film to prepare a PET film with an underlayer. The target used during magnetron sputtering is the silicon carbide-aluminum oxide mixture, and the molar ratio of silicon carbide to aluminum oxide is 3:2. The magnetron sputtering process parameters are as follows: the argon gas flow rate is 100 mL / min, the coating vacuum degree is 0.08 Pa, the temperature of the main roller during the coating process is -10 °C, and the thickness of the prepared underlayer is 20 nm.

[0045] Step 2: Place the PET film with the underlayer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the underlayer, forming an aluminum metal layer with a thickness of 1 μm.

[0046] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on its surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0047] Example 6: A processing technology for a high-performance current collector, specifically as follows:

[0048] Step 1: Magnetron sputter a zirconium oxide-aluminum oxide mixture on the surface of the PET film to prepare a PET film with an underlayer. The target used during magnetron sputtering is the zirconium oxide-aluminum oxide mixture, and the molar ratio of zirconium oxide to aluminum oxide is 2:1. The magnetron sputtering process parameters are as follows: the argon gas flow rate is 100 mL / min, the coating vacuum degree is 0.08 Pa, the temperature of the main roller during the coating process is -10 °C, and the thickness of the prepared underlayer is 20 nm.

[0049] Step 2: Place the PET film with the underlayer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the underlayer, forming an aluminum metal layer with a thickness of 1 μm.

[0050] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on its surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0051] Example 7: A processing technology for a high-performance current collector, specifically as follows:

[0052] Step 1: Magnetron sputter silicon-aluminum on the surface of the PET film to prepare a PET film with an underlayer. The target used for magnetron sputtering is silicon-aluminum, with a purity > 99.9%, a silicon-aluminum molar ratio of 1:12, and magnetron sputtering process parameters including an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process being -10°C. The thickness of the prepared underlayer is 20 nm;

[0053] Step 2: Place the PET film with the underlayer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the underlayer to form an aluminum metal layer with a thickness of 1 μm.

[0054] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on its surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so as to form an aluminum oxide protective layer with a thickness of 3 nm on the surface of the metal layer, and obtain a high-performance current collector.

[0055] Example 8: A processing technology for a high-performance current collector, specifically as follows:

[0056] Step 1: Magnetron sputter a mixture of aluminum nitride - aluminum oxide on the surface of the PET film to prepare a PET film with an underlayer. The target used for magnetron sputtering is a mixture of aluminum nitride - aluminum oxide, with a molar ratio of aluminum nitride to aluminum oxide of 1:1, and magnetron sputtering process parameters including an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process being -10°C. The thickness of the prepared underlayer is 20 nm;

[0057] Step 2: Place the PET film with the underlayer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the underlayer to form an aluminum metal layer with a thickness of 1 μm.

[0058] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on its surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so as to form an aluminum oxide protective layer with a thickness of 3 nm on the surface of the metal layer, and obtain a high-performance current collector.

[0059] Example 9: A processing technology for a high-performance current collector, specifically as follows:

[0060] Step 1: Magnetron sputter silicon carbide on the surface of the PET film to prepare a PET film with a primer layer. The target used for magnetron sputtering is silicon carbide with a purity > 99.9%. The magnetron sputtering process parameters are as follows: the argon flow rate is 100 mL / min, the coating vacuum degree is 0.08 Pa, the temperature of the main roller during the coating process is -10 °C, and the thickness of the primer layer obtained is 20 nm;

[0061] Step 2: Place the prepared PET film with a primer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with a primer layer to form an aluminum metal layer with a thickness of 1 μm.

[0062] Step 3: After the evaporation is completed, take out the PET film with an aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0063] Example 10: A processing technology for a high-performance current collector, specifically:

[0064] Step 1: Magnetron sputter nickel silicide on the surface of the PET film to prepare a PET film with a primer layer. The target used for magnetron sputtering is nickel silicide with a purity > 99.9%, the molar ratio of nickel to silicon is 10:3, the magnetron sputtering process parameters are as follows: the argon flow rate is 100 mL / min, the coating vacuum degree is 0.08 Pa, the temperature of the main roller during the coating process is -10 °C, and the thickness of the primer layer obtained is 20 nm;

[0065] Step 2: Place the prepared PET film with a primer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with a primer layer to form an aluminum metal layer with a thickness of 1 μm.

[0066] Step 3: After the evaporation is completed, take out the PET film with an aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0067] Example 11: A processing technology for a high-performance current collector, specifically:

[0068] Step 1: Dissolve 60 g of maleic anhydride in 2000 g of deionized water, stir evenly to obtain a maleic anhydride solution. Dissolve 2 g of styrene and 0.2 g of benzoyl peroxide in 45 g of xylene, stir evenly to obtain a styrene mixed solution. At 80 °C, add the styrene mixed solution to the maleic anhydride solution, stir, and after thorough mixing, immerse the PET film in the mixed solution. Subsequently, transfer the mixed solution together with the PET film to a microwave reactor, keep the temperature of the mixed solution at 80 °C, set the microwave power to 700 W, and the reaction time to 30 min. During the reaction, maintain the concentrations of maleic anhydride, styrene, and benzoyl peroxide in the mixed solution. After the reaction is completed, take out the PET film, rinse it with acetone, and dry it to obtain a maleic anhydride-modified PET film;

[0069] Step 2: Magnetron sputter nickel-aluminum on the surface of the maleic anhydride-modified PET film to prepare a maleic anhydride-modified PET film with an underlayer. The target material used for magnetron sputtering is nickel-aluminum, with a purity > 99.9%, a nickel-aluminum molar ratio of 2:1. The magnetron sputtering process parameters are as follows: the argon flow rate is 100 mL / min, the coating vacuum degree is 0.08 Pa, and the temperature of the main roller during the coating process is -10 °C. The thickness of the prepared underlayer is 20 nm;

[0070] Step 3: Place the maleic anhydride-modified PET film with the underlayer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the maleic anhydride-modified PET film with the underlayer to form an aluminum metal layer with a thickness of 1 μm.

[0071] Step 4: After the evaporation is completed, take out the PET film with an aluminum metal layer on the surface and place it in the air to allow the aluminum metal layer on the surface to naturally oxidize, so as to form an aluminum oxide protective layer with a thickness of 3 nm on the surface of the metal layer, and obtain a high-performance current collector.

[0072] Next, control experiments are carried out, specifically Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, as described below:

[0073] Comparative Example 1: This comparative example relates to a processing technology of a high-performance current collector. The difference from Example 1 is that the underlayer material selected is nickel-chromium-aluminum, and the nickel-chromium-aluminum molar ratio is 1:2:1. Specifically:

[0074] Step 1: Magnetron sputter nickel-chromium-aluminum on the surface of the PET film to prepare a PET film with a bonding layer. The target used for magnetron sputtering is nickel-chromium-aluminum with a purity > 99.9%, a nickel-chromium-aluminum molar ratio of 1:2:1. The magnetron sputtering process parameters are an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process is -10°C. The thickness of the bonding layer obtained is 20 nm;

[0075] Step 2: Place the PET film with the bonding layer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the bonding layer to form an aluminum metal layer with a thickness of 1 μm.

[0076] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0077] Comparative Example 2: This comparative example relates to a processing technology of a high-performance current collector. The difference from Example 1 is that the bonding layer material selected is silicon dioxide, specifically:

[0078] Step 1: Magnetron sputter silicon dioxide on the surface of the PET film to prepare a PET film with a bonding layer. The target used for magnetron sputtering is silicon dioxide with a purity > 99.9%. The magnetron sputtering process parameters are an argon flow rate of 100 mL / min, a coating vacuum of 0.08 Pa, and the temperature of the main roller during the coating process is -10°C. The thickness of the bonding layer obtained is 20 nm;

[0079] Step 2: Place the PET film with the bonding layer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the bonding layer to form an aluminum metal layer with a thickness of 1 μm.

[0080] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an aluminum oxide protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0081] Comparative Example 3: This comparative example relates to a processing technology of a high-performance current collector. The difference from Example 1 is that the bonding layer material selected is aluminum oxide, specifically:

[0082] Step 1: Magnetron sputter alumina on the surface of the PET film to prepare a PET film with a primer layer. The target used for magnetron sputtering is alumina with a purity > 99.9%. The magnetron sputtering process parameters are as follows: the argon gas flow rate is 100 mL / min, the coating vacuum degree is 0.08 Pa, the temperature of the main roller during the coating process is -10 °C, and the thickness of the primer layer obtained is 20 nm;

[0083] Step 2: Place the PET film with the primer layer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the primer layer to form an aluminum metal layer with a thickness of 1 μm.

[0084] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an alumina protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0085] Comparative Example 4: This comparative example relates to a processing technology of a high-performance current collector. The difference from Example 1 is that the primer layer material selected is zirconia, specifically:

[0086] Step 1: Magnetron sputter zirconia on the surface of the PET film to prepare a PET film with a primer layer. The target used for magnetron sputtering is zirconia with a purity > 99.9%. The magnetron sputtering process parameters are as follows: the argon gas flow rate is 100 mL / min, the coating vacuum degree is 0.08 Pa, the temperature of the main roller during the coating process is -10 °C, and the thickness of the primer layer obtained is 20 nm;

[0087] Step 2: Place the PET film with the primer layer prepared above in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber at a high temperature of 1300 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both surfaces of the PET film with the primer layer to form an aluminum metal layer with a thickness of 1 μm.

[0088] Step 3: After the evaporation is completed, take out the PET film with the aluminum metal layer on the surface and place it in the air to naturally oxidize the aluminum metal layer on the surface, so that an alumina protective layer with a thickness of 3 nm can be formed on the surface of the metal layer, and a high-performance current collector is obtained.

[0089] Detection experiment:

[0090] Adhesion test: Process high-performance current collectors as the positive current collector according to the processing technologies in Examples 1-11 and Comparative Examples 1, 2, 3, and 4 respectively. Prepare LiNi on the surface of the positive current collector 0.6Mn 0.2 Co 0.2 The positive electrode active material layer using O2 (NCM622) as the positive electrode active material is roll-pressed (roll-pressed density ≤ 4.3 g / cm 3 ) to compact it, obtaining a positive electrode plate. The positive electrode plate is immersed in an electrolyte (a 1 mol / L lithium hexafluorophosphate solution, and the solvent is a mixed solution of propylene carbonate, ethylene carbonate, and ethyl methyl carbonate in a mass ratio of 1:1:1) for 7 days, and its adhesion is tested.

[0091] Battery capacity retention test: High-performance current collectors are processed according to the processing techniques in Examples 1-11 and Comparative Examples 1, 2, 3, and 4 respectively as the positive electrode current collectors. On the surface of the positive electrode current collector, a positive electrode active material layer using LiNi 0.6 Mn 0.2 Co 0.2 O2 (NCM622) as the positive electrode active material is roll-pressed (roll-pressed density ≤ 4.3 g / cm 3 ) to compact it, obtaining a positive electrode plate. A copper foil with a thickness of 6 μm is used as the negative electrode current collector, and a negative electrode active material layer using artificial graphite as the negative electrode active material is prepared on the surface of the negative electrode current collector as a conventional negative electrode plate. An alumina ceramic-coated polyethylene separator (with a thickness of 25 μm) is used as the separator. The electrolyte of the lithium-ion battery is a 1 mol / L lithium hexafluorophosphate solution (the solvent is a mixed solution of propylene carbonate, ethylene carbonate, and ethyl methyl carbonate in a mass ratio of 1:1:1). The above composite positive electrode plate, separator, and conventional negative electrode plate are stacked in sequence to prepare a bare battery cell. The bare battery cell is placed in a lithium battery outer packaging case, dried and then injected with electrolyte, and after processes such as vacuum packaging, standing, formation, and shaping, a lithium-ion battery is obtained. At 45 °C, with a charge-discharge rate of 1C, the battery is cyclically charged and discharged 800 times within a voltage range of 3.0 V to 4.2 V, and the battery capacity retention rate after the cyclic charge and discharge is recorded.

[0092]

[0093] Conclusion: It can be seen from the test data that the high-performance current collector processed by the processing technique of the high-performance current collector provided by the present invention has excellent adhesion. After being assembled into a lithium-ion battery and undergoing 800 charge-discharge cycle tests, it can still maintain a good capacity cycle retention rate. The high-performance current collector processed according to the processing technique of the high-performance current collector in the present invention has a high strength of the underlayer, can maintain a stable structure during the roll-pressing process of the electrode plate, and further realizes the structural stability of the metal layer and the base film during the battery cycle process, avoiding the problem of defects generated by the extrusion of the underlayer by silicon dioxide during the roll-pressing process of the electrode plate and the delamination of the base film and the metal layer caused by the subsequent electrolyte immersion, thereby improving the performance of the battery.

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics thereof. Therefore, in all respects, the embodiments should be considered exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description. Accordingly, all changes that fall within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

Claims

1. A high-performance current collector, characterized in that: It includes a base film layer, and primer layers disposed on both surface sides of the base film layer. A metal layer is disposed on the side of the primer layer away from the base film layer. The material of the primer layer is one or more combinations of silicon aluminum, silicon dioxide - aluminum oxide mixture, aluminum nitride, aluminum nitride - aluminum oxide mixture, silicon carbide, silicon carbide - aluminum oxide mixture, zirconium oxide - aluminum oxide mixture, nickel aluminum, nickel silicon, nickel chromium, and nickel chromium aluminum.

2. The high-performance current collector according to claim 1, wherein: In silicon aluminum, the molar ratio of silicon to aluminum is 1:(11 - 15); in the silicon dioxide - aluminum oxide mixture, the molar ratio of silicon dioxide to aluminum oxide is 1:1; in the aluminum nitride - aluminum oxide mixture, the molar ratio of aluminum nitride to aluminum oxide is 1:(0.5 - 2); in the silicon carbide - aluminum oxide mixture, the molar ratio of silicon carbide to aluminum oxide is 1:(0.5 - 2); in the zirconium oxide - aluminum oxide mixture, the molar ratio of zirconium oxide to aluminum oxide is 1:(0.4 - 0.8); in nickel aluminum, the molar ratio of nickel to aluminum is 1:(0.5 - 1); in nickel silicon, the molar ratio of nickel to silicon is 1:(0.2 - 0.5); in nickel chromium, the molar ratio of nickel to chromium is 1:(0.2 - 0.5); in nickel chromium aluminum, the molar ratio of nickel, chromium, and aluminum is 1:(0.5 - 1):(0.2 - 0.5).

3. A high-performance current collector according to claim 1, characterized in that: The material of the metal layer is one or more combinations of copper, aluminum, copper alloy, and aluminum alloy.

4. The high-performance current collector according to claim 1, wherein: A protective layer is provided outside the metal layer. The material of the protective layer is one or more combinations of nickel, chromium, nickel - based alloy, copper - based alloy, copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, graphite, carbon black, copper chromium oxide, carbon nano quantum dot, carbon nanotube, carbon nanofiber, and graphene.

5. A high-performance current collector according to claim 1, characterized in that: The thickness of the primer layer disposed on any side of the base film is 1 nm - 50 nm, preferably 2 nm - 20 nm.

6. The high-performance current collector according to claim 1, characterized in that: The material of the base film layer is one or more combinations of polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyimide, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene ether, polystyrene, and polyamide.

7. The high-performance current collector according to claim 1, characterized in that: The high - performance current collector meets any one of the following conditions: (1) The thickness of the base film layer of the current collector is 1 μm - 10 μm; (2) The thickness of the metal layer of the current collector is 500 nm - 2000 nm; (3) The thickness of the protective layer of the current collector is 2 nm - 100 nm, preferably 10 nm - 80 nm.

8. A high-performance current collector according to claim 1, characterized in that: The base film layer is a maleic anhydride - modified base film, and the preparation method is as follows: Dissolve maleic anhydride in deionized water and stir evenly to obtain a maleic anhydride solution. Dissolve styrene and benzoyl peroxide in xylene and stir evenly to obtain a styrene mixed solution. At 75 - 85 °C, immerse the base film in the mixed solution of the styrene mixed solution and the maleic anhydride solution, and then perform microwave irradiation treatment, maintaining the temperature of the mixed solution at 75 - 85 °C, setting the microwave power to 600 - 750 W, and the reaction time to 5 - 30 min. After the reaction is completed, take out the base film, rinse it with acetone, and dry it to obtain the maleic anhydride - modified base film.

9. A method for preparing a high-performance current collector, characterized in that: Specifically: Step 1: Magnetron sputter a bottom layer on the surface of the base film layer. The target used during magnetron sputtering is the bottom layer material. During magnetron sputtering, the argon gas flow rate is 90 - 100 mL / min, the coating vacuum degree is 0.06 - 0.08 Pa, and the temperature of the main roller during the coating process is -10 - 0 °C; Step 2: Vacuum deposit on the outer surface of the bottom layer. Melt and evaporate the metal layer material at a high temperature of 1200 - 1300 °C. After evaporation, the metal atoms are cooled and deposited on the outer surface of the bottom layer to form a metal layer.

10. Application of a high-performance current collector according to any one of claims 1 - 8 in a battery.

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